® RT8179B Dual-Output PWM Controller with 2 Integrated Drivers for AMD SVI2 Mobile CPU Power Supply General Description Features The RT8179B is a dual-output PWM controller, and is compliant with AMD SVI2 Voltage Regulator Specification to support both CPU core (VDD) and Northbridge portion of the CPU (VDDNB). The RT8179B features CCRCOT (Constant Current Ripple Constant On-Time) with G-NAVP (Green-Native AVP), which is Richtek's proprietary topology. G-NAVP makes it an easy setting controller to meet all AMD AVP (Adaptive Voltage Positioning) VDD/ VDDNB requirements. The droop is easily programmed by setting the DC gain of the error amplifier. With proper compensation, the load transient response can achieve optimized AVP performance. The controller also uses the interface to issue VOTF Complete and to send digitally encoded voltage and current values for the VDD and VDDNB domains. It can operate in diode emulation mode and reach up to 90% efficiency in different modes according to different loading conditions. The RT8179B provides special purpose offset capabilities by pin setting. The RT8179B also provides power good indication, over current indication (OCP_L) and dual OCP mechanism for AMD SVI2 CPU core and NB. It also features complete fault protection functions including over voltage, under voltage and negative voltage. 1-Phase (VDD) + 1-Phase (VDDNB) PWM Controller 2 Embedded MOSFET Drivers G-NAVPTM Topology Support Dynamic Load-Line and Zero Load-Line Diode Emulation Mode at Light Load Condition SVI2 Interface to Comply with AMD Power Management Protocol Build-in ADC for VOUT and IOUT Reporting Immediate OV, UV and NV Protections and UVLO Programmable Dual OCP Mechanisms DVID Turbo Boost Compensation 0.5% DAC Accuracy Fast Transient Response Power Good Indicator Over Current Indicator 40-Lead WQFN Package RoHS Compliant and Halogen Free Applications AMD SVI2 Mobile CPU Laptop Computer Simplified Application Circuit RT8179B OCP_L PHASE MOSFET VVDD PHASEA MOSFET VVDDNB SVC To CPU SVD SVT Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8179B Ordering Information Pin Configurations (TOP VIEW) RT8179B UGATE PHASE LGATE PVCC LGATEA PHASEA UGATEA BOOTA TONSETA PGOOD Package Type QW : WQFN-40L 5x5 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) Richtek products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Marking Information RT8179BGQW : Product Number RT8179B GQW YMDNN YMDNN : Date Code Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 1 30 2 29 3 28 4 27 5 26 GND 25 6 24 7 8 41 23 22 9 21 10 PGOODA EN ISENA1P ISENA1N VSENA FBA COMPA IBIAS VCC OCP_L 11 12 13 14 15 16 17 18 19 20 IMONA VDDIO PWROK SVC SVD SVT OFS OFSA SET1 SET2 Note : 40 39 38 37 36 35 34 33 32 31 BOOT TONSET ISEN1N ISEN1P VSEN FB COMP RGND IMON V064 WQFN-40L 5x5 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Functional Pin Description Pin No. Pin Name Pin Function 1, 33 BOOT, BOOTA Bootstrap Supply for High Side MOSFET. This pin powers high side MOSFET driver. 2 TONSET VDD Controller On-Time Setting. Connect this pin to the converter input voltage, VIN, through a resistor, RTON, to set the on-time of UGATE and also the output voltage ripple of VDD controller. 4 ISEN1P Positive Current Sense Input of Channel 1 for VDD Controller. 3 ISEN1N Negative Current Sense Input of Channel 1 for VDD Controller. 5 VSEN VDD Controller Voltage Sense Input. This pin is connected to the terminal of VDD controller output voltage. 6 FB Output Voltage Feedback Input of VDD Controller. This pin is the negative input of the error amplifier for the VDD controller. 7 COMP 8 RGND 9 IMON 10 V064 Fixed 0.64V Output Reference Voltage Output. This voltage is only used to offset the output voltage of the IMON pin and the IMONA pin. Connect a 0.47F capacitor from this pin to GND. 11 IMONA Current Monitor Output for the VDDNB Controller. This pin outputs a voltage proportional to the output current. 12 VDDIO Processor Memory Interface Power Rail and Serves as the Reference for PWROK, SVD, SVC and SVT. This pin is used by the VR to reference the SVI pins. 13 PWROK System Power Good Input. If PWROK is low, the SVI interface is disabled and VR returns to BOOT-VID state with initial load-line slope and initial offset. If PWROK is high, the SVI interface is running and the DAC decodes the received serial VID codes to determine the output voltage. 14 SVC Serial VID Clock Input from Processor. 15 SVD Serial VID Data Input from Processor. This pin is a serial data line. 16 SVT Serial VID Telemetry Input from VR. This pin is a push-pull output. 17 OFS Over Clocking Offset Setting for the VDD Controller. 18 OFSA Over Clocking Offset Setting for the VDDNB Controller. 19 SET1 1st Platform Setting Pin. Platform can use this pin to set OCP_TDC threshold, DVID compensation bit1 and internal ramp slew rate. 20 SET2 2st Platform Setting Pin. Platform can use this pin to set quick response threshold, OCP_TDC trigger delay time, DVID compensation bit0, VDDNB rail zero load-line enable setting and over clocking offset enable setting. 21 OCP_L Over Current Indicator for Dual OCP Mechanism. This pin is an open drain output. 22 VCC Controller Power Supply Input. Connect this pin to 5V with an 1F or greater ceramic capacitor for decoupling. Error Amplifier Output Pin of the VDD Controller. Return Ground of VDD and VDDNB Controller. This pin is the common negative input of output voltage differential remote sense for VDD and VDDNB controllers. Current Monitor Output for the VDD Controller. This pin outputs a voltage proportional to the output current. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8179B Pin No. Pin Name Pin Function 23 IBIAS Internal Bias Current Setting. Connect only a 100k resistor from this pin to GND to generate bias current for internal circuit. Place this resistor as close to IBIAS pin as possible. 24 COMPA Error Am plifier Output of the VDDNB Controller. 25 FBA Output Voltage Feedback Input of VDDNB Controller. This pin is the negative input of the error amplifier for the VDDNB controller. 26 VSENA VDDNB Controller Voltage Sense Input. This pin is connected to the terminal of VDDNB controller output voltage. 27 ISENA1N Negative Current Sense Input of Channel 1 for VDDNB Controller. 28 ISENA1P Positive Current Sense Input of Channel 1 for VDDNB Controller. 29 EN Controller Enable pin. A logic high signal enables the controller. 30 PGOODA 31 PGOOD 32 TONSETA Power Good Indicator for the VDDNB Controller. This pin is an open drain output. Power Good Indicator for the VDD Controller. This pin is an open drain output. VDDNB Controller On-Time Setting. Connect this pin to the converter input voltage, VIN, through a resistor, RTONNB, to set the on-time of UGATE_VDDNB and also the output voltage ripple of VDDNB controller. 34, 40 UGATEA UGATE, Upper Gate Driver Outputs. Connect this pin to Gate of high side MOSFET. 35, 39 PHASEA PHASE, Switch Nodes of High Side Driver. Connect this pin to high side MOSFET Source together with the low side MOSFET Drain and the inductor. 36, 38 LGATEA LGATE, Lower Gate Driver Outputs. This pin drives the gate of low side MOSFET. 37 PVCC Driver Power. Connect this pin to GND by ceramic capacitor larger than 1F. 41 (Exposed Pad) GND Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B PGOODA OCP_L PGOOD VCC EN PWROK VDDIO SVT SVD SVC VSEN VSENA OFSA IMONI IMONAI OFS SET2 SET1 Function Block Diagram UVLO GND MUX ADC SVI2 Interface Configuration Registers Control Logic IBIAS OFS/OFSA Load Line /Load Line A From Control Logic RGND Loop Control Protection Logic RSET/RSETA TONSETA OCP Threshold DAC Soft-Start & Slew Rate Control ERROR VSETA AMP + + Offset Cancellation - FBA COMPA + - QRA PWM CMPA TON GENA PWMA BOOTA 1-PH Driver TONA Current mirror ISENA1P + x2 - ISENA1N UGATEA PHASEA LGATEA IBA1 V064 + 0.4 - RSETA Average IMONA + OCP_TDCA, OCP_SPIKEA From Control Logic RGND IMONAI OCA - Driver POR TONSET OV/UV/NV VSENA DAC Soft-Start & Slew Rate Control VSET FB ERROR AMP + BOOT Offset Cancellation + Current mirror + x1 - PWM1 + - COMP ISEN1P ISEN1N PVCC To Protection Logic PWM CMP QR TON GEN 1-PH Driver UGATE PHASE LGATE TON IB1 + 0.4 - RSET Average OCP_TDC, OCP_SPIKE IMONI + OC - VSEN To Protection Logic OV/UV/NV IMON V064 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT8179B Operation MUX and ADC Error Amplifier The MUX supports the inputs from SET1, SET2, OFS, OFSA, IMONI, IMONAI, VSEN, or VSENA. The ADC converts these analog signals to digital codes for reporting or performance adjustment. Error amplifier generates COMP/COMPA signal by the difference between VSET/VSETA and FB/FBA. SVI2 Interface The SVI2 interface uses the SVC, SVD, and SVT pins to communicate with CPU. The RT8179B's performance and behavior can be adjusted by commands sent by CPU or platform. Offset Cancellation This block cancels the output offset voltage from voltage ripple and current ripple to achieve accurate output voltage. PWM CMPx The PWM comparator compares COMP signal and current feedback signal to generate a signal for TONGENx. UVLO TONGEN/TONGENA The UVLO detects the VCC pin voltages for under voltage lockout protection and power on reset operation. This block generates an on-time pulse which high interval is based on the on-time setting and current balance. Loop Control Protection Logic OC/OV/UV/NV Loop control protection logic detects EN and UVLO signals to initiate soft-start function and control PGOOD, PGOODA and OCP_L signals after soft-start is finished. When dual OCP event occurs, the OCP_L pin voltage will be pulled low. VSEN/VSENA and output current are sensed for over current, over voltage, under voltage, and negative voltage protection. DAC RSET/RSETA The Ramp generator is designed to improve noise immunity and reduce jitter. The DAC receives VID codes from the SVI2 control logic to generate an internal reference voltage (VSET/VSETA) for controller. Soft-Start and Slew-Rate Control This block controls the slew rate of the internal reference voltage when output voltage changes. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Table 1. Serial VID Codes SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) 0000_0000 1.55000 0010_0111 1.30625 0100_1110 1.06250 0111_0101 0.81875 0000_0001 1.54375 0010_1000 1.30000 0100_1111 1.05625 0111_0110 0.81250 0000_0010 1.53750 0010_1001 1.29375 0101_0000 1.05000 0111_0111 0.80625 0000_0011 1.53125 0010_1010 1.28750 0101_0001 1.04375 0111_1000 0.80000 0000_0100 1.52500 0010_1011 1.28125 0101_0010 1.03750 0111_1001 0.79375 0000_0101 1.51875 0010_1100 1.27500 0101_0011 1.03125 0111_1010 0.78750 0000_0110 1.51250 0010_1101 1.26875 0101_0100 1.02500 0111_1011 0.78125 0000_0111 1.50625 0010_1110 1.26250 0101_0101 1.01875 0111_1100 0.77500 0000_1000 1.50000 0010_1111 1.25625 0101_0110 1.01250 0111_1101 0.76875 0000_1001 1.49375 0011_0000 1.25000 0101_0111 1.00625 0111_1110 0.76250 0000_1010 1.48750 0011_0001 1.24375 0101_1000 1.00000 0111_1111 0.75625 0000_1011 1.48125 0011_0010 1.23750 0101_1001 0.99375 1000_0000 0.75000 0000_1100 1.47500 0011_0011 1.23125 0101_1010 0.98750 1000_0001 0.74375 0000_1101 1.46875 0011_0100 1.22500 0101_1011 0.98125 1000_0010 0.73750 0000_1110 1.46250 0011_0101 1.21875 0101_1100 0.97500 1000_0011 0.73125 0000_1111 1.45625 0011_0110 1.21250 0101_1101 0.96875 1000_0100 0.72500 0001_0000 1.45000 0011_0111 1.20625 0101_1110 0.96250 1000_0101 0.71875 0001_0001 1.44375 0011_1000 1.20000 0101_1111 0.95625 1000_0110 0.71250 0001_0010 1.43750 0011_1001 1.19375 0110_0000 0.95000 1000_0111 0.70625 0001_0011 1.43125 0011_1010 1.18750 0110_0001 0.94375 1000_1000 0.70000 0001_0100 1.42500 0011_1011 1.18125 0110_0010 0.93750 1000_1001 0.69375 0001_0101 1.41875 0011_1100 1.17500 0110_0011 0.93125 1000_1010 0.68750 0001_0110 1.41250 0011_1101 1.16875 0110_0100 0.92500 1000_1011 0.68125 0001_0111 1.40625 0011_1110 1.16250 0110_0101 0.91875 1000_1100 0.67500 0001_1000 1.40000 0011_1111 1.15625 0110_0110 0.91250 1000_1101 0.66875 0001_1001 1.39375 0100_0000 1.15000 0110_0111 0.90625 1000_1110 0.66250 0001_1010 1.38750 0100_0001 1.14375 0110_1000 0.90000 1000_1111 0.65625 0001_1011 1.38125 0100_0010 1.13750 0110_1001 0.89375 1001_0000 0.65000 0001_1100 1.37500 0100_0011 1.13125 0110_1010 0.88750 1001_0001 0.64375 0001_1101 1.36875 0100_0100 1.12500 0110_1011 0.88125 1001_0010 0.63750 0001_1110 1.36250 0100_0101 1.11875 0110_1100 0.87500 1001_0011 0.63125 0001_1111 1.35625 0010_0110 1.11250 0110_1101 0.86875 1001_0100 0.62500 0010_0000 1.35000 0100_0111 1.10625 0110_1110 0.86250 1001_0101 0.61875 0010_0001 1.34375 0100_1000 1.10000 0110_1111 0.85625 1001_0110 0.61250 0010_0010 1.33750 0100_1001 1.09375 0111_0000 0.85000 1001_0111 0.60625 0010_0011 1.33125 0100_1010 1.08750 0111_0001 0.84375 1001_1000 0.60000 0010_0100 1.32500 0100_1011 1.08125 0111_0010 0.83750 1001_1001 0.59375 0010_0101 1.31875 0100_1100 1.07500 0111_0011 0.83125 1001_1010 0.58750 0010_0110 1.31250 0100_1101 1.06875 0111_0100 0.82500 1001_1011 0.58125 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT8179B SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) SVID [7:0] Voltage (V) 1001_1100 0.57500 1011_0101 * 0.41875 1100_1110 * 0.26250 1110_0111* 0.10625 1001_1101 0.56875 1011_0110 * 0.41250 1100_1111 * 0.25625 1110_1000* 0.10000 1001_1110 0.56250 1011_0111 * 0.40625 1101_0000 * 0.25000 1110_1001* 0.09375 1001_1111 0.55625 1011_1000 * 0.40000 1101_0001 * 0.24375 1110_1010* 0.08750 1010_0000 0.55000 1011_1001 * 0.39375 1101_0010 * 0.23750 1110_1011* 0.08125 1010_0001 0.54375 1011_1010 * 0.38750 1101_0011 * 0.23125 1110_1100* 0.07500 1010_0010 0.53750 1011_1011 * 0.38125 1101_0100 * 0.22500 1110_1101* 0.06875 1010_0011 0.53125 1011_1100 * 0.37500 1101_0101 * 0.21875 1110_1110* 0.06250 1010_0100 0.52500 1011_1101 * 0.36875 1101_0110 * 0.21250 1110_1111* 0.05625 1010_0101 0.51875 1011_1110 * 0.36250 1101_0111 * 0.20625 1111_0000* 0.05000 1010_0110 0.51250 1011_1111 * 0.35625 1101_1000 * 0.20000 1111_0001* 0.04375 1010_0111 0.50625 1100_0000 * 0.35000 1101_1001 * 0.19375 1111_0010* 0.03750 1010_1000 * 0.50000 1100_0001 * 0.34375 1101_1010 * 0.18750 1111_0011* 0.03125 1010_1001 * 0.49375 1100_0010 * 0.33750 1101_1011 * 0.18125 1111_0100* 0.02500 1010_1010 * 0.48750 1100_0011 * 0.33125 1101_1100 * 0.17500 1111_0101* 0.01875 1010_1011 * 0.48125 1100_0100 * 0.32500 1101_1101 * 0.16875 1111_0110* 0.01250 1010_1100 * 0.47500 1100_0101 * 0.31875 1101_1110 * 0.16250 1111_0111* 0.00625 1010_1101 * 0.46875 1100_0110 * 0.31250 1101_1111 * 0.15625 1111_1000* 0.00000 1010_1110 * 0.46250 1100_0111 * 0.30625 1110_0000* 0.15000 1111_1001* OFF 1010_1111 * 0.45625 1100_1000 * 0.30000 1110_0001* 0.14375 1111_1010* OFF 1011_0000 * 0.45000 1100_1001 * 0.29375 1110_0010* 0.13750 1111_1011* OFF 1011_0001 * 0.44375 1100_1010 * 0.28750 1110_0011* 0.13125 1111_1100* OFF 1011_0010 * 0.43750 1100_1011 * 0.28125 1110_0100* 0.12500 1111_1101* OFF 1011_0011 * 0.43125 1100_1100 * 0.27500 1110_0101* 0.11875 1111_1110* OFF 1011_0100 * 0.42500 1100_1101 * 0.26875 1110_0110* 0.11250 1111_1111* OFF * Indicates TOB is 80mV for this VID code; unconditional VR controller stability required at all VID codes Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Table 2. SET1 Pin Setting for VDD Controller OCP_TDC Threshold, DVID Compensation and Ramp Ratio (RSET) RSET SET1 Pin Voltage Before Current Injection VSET1 (mV) 34 145% 836 145% 59 130% 861 130% 115% 886 100% 911 135 85% 936 85% 160 70% 961 70% 235 145% 1036 145% 260 130% 1061 130% 115% 1086 100% 1112 335 85% 1137 85% 360 70% 1162 70% 435 145% 1237 145% 460 130% 1262 130% 115% 1287 100% 1312 535 85% 1337 85% 560 70% 1362 70% 636 145% 1437 145% 661 130% 1462 130% 115% 1487 100% 1512 736 85% 1537 85% 761 70% 1562 70% SET1 Pin Voltage Before Current Injection VSET1 (mV) 85 110 285 310 485 510 686 711 OCP_TDC (Respect to OCP_ SPIKE) 60% 70% 75% Disable DVID Compensation [1] 0 0 0 0 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 OCP_TDC (Respect to OCP_ SPIKE) 60% 70% 75% Disable DVID Compensation [1] 1 1 1 1 RSET 115% 100% 115% 100% 115% 100% 115% 100% is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT8179B Table 3. SET1 Pin Setting for VDDNB Controller OCP_TDCA Threshold, DVIDA Compensation and Ramp Ratio (RSETA) SET1 Pin SET1 Pin Voltage Voltage OCP_TDCA OCP_TDCA DVIDA Difference DVIDA Difference (Respect to (Respect to Compensation RSETA VSET1 (Before Compensation RSETA VSET1 (Before OCP_ OCP_ [1] [1] and After and After SPIKEA) SPIKEA) Current Current Injection) (mV) Injection) (mV) 34 145% 836 145% 59 130% 861 130% 115% 886 100% 911 135 85% 936 85% 160 70% 961 70% 235 145% 1036 145% 260 130% 1061 130% 115% 1086 100% 1112 335 85% 1137 85% 360 70% 1162 70% 435 145% 1237 145% 460 130% 1262 130% 115% 1287 100% 1312 535 85% 1337 85% 560 70% 1362 70% 636 145% 1437 145% 661 130% 1462 130% 115% 1487 100% 1512 736 85% 1537 85% 761 70% 1562 70% 85 110 285 310 485 510 686 711 60% 70% 75% Disable 0 0 0 0 Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 60% 70% 75% Disable 1 1 1 1 115% 100% 115% 100% 115% 100% 115% 100% is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Table 4. SET2 Pin Setting for VDD Controller QR Threshold, DVID Compensation, NB 0LL and OCP Trigger Delay NB OLL Setting OCPTRGDELAY (for VDD/VDDNB) 0 10ms 0 40ms 122 1 10ms 172 1 40ms 222 0 10ms 0 40ms 323 1 10ms 373 1 40ms 423 0 10ms 0 40ms 523 1 10ms 573 1 40ms 623 0 10ms 0 40ms 723 1 10ms 773 1 40ms 823 0 10ms 0 40ms 924 1 10ms 974 1 40ms 1024 0 10ms 0 40ms 1124 1 10ms 1174 1 40ms 1224 0 10ms 0 40ms 1324 1 10ms 1375 1 40ms 1425 0 10ms 0 40ms 1525 1 10ms 1575 1 40ms SET2 Pin Voltage Before Current Injection VSET2 (mV) QRTH (for VDD) DVID Compensation [0] 19 72 272 473 673 874 Disable 39mV 47mV 55mV Disable 0 0 0 0 1 1074 39mV 1274 1475 47mV 55mV Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 1 1 1 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT8179B Table 5. SET2 Pin Setting for VDDNB Controller QR Threshold, DVIDA Compensation and External Offset Function SET2 Pin Voltage Difference VSET2 (Before and After Current Injection) (mV) OFSENABLE OFSAENABLE DVIDA Compensation [0] 19 QRTHA (for VDDNB) Disable 72 39mV 0 122 47mV 172 55mV 0 222 Disable 272 1 323 373 39mV 47mV 55mV 0 423 Disable 473 39mV 0 523 47mV 573 55mV 1 623 Disable 673 39mV 1 723 47mV 773 55mV 823 Disable 874 39mV 0 924 47mV 974 55mV 0 1024 Disable 1074 39mV 1 1124 47mV 1174 55mV 1 1224 Disable 1274 39mV 0 1324 47mV 1375 55mV 1 1425 Disable 1475 39mV 1 1525 47mV 1575 55mV Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Table 6. DVID Boost Compensation Setting DVID Compensation [1] DVID Compensation [0] DVID Boost Compensation 0 0 22.5mV 0 1 18mV 1 0 13.5mV 1 1 9mV Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT8179B Absolute Maximum Ratings (Note 1) VCC to GND --------------------------------------------------------------------------------------------------------PVCC to GND ------------------------------------------------------------------------------------------------------RGND to GND ------------------------------------------------------------------------------------------------------TONSET, TONSETA to GND ------------------------------------------------------------------------------------BOOTx to PHASEx -----------------------------------------------------------------------------------------------PHASEx to GND DC ---------------------------------------------------------------------------------------------------------------------< 20ns ---------------------------------------------------------------------------------------------------------------LGATEx to GND DC ---------------------------------------------------------------------------------------------------------------------< 20ns ---------------------------------------------------------------------------------------------------------------UGATEx to PHASEx DC ---------------------------------------------------------------------------------------------------------------------< 20ns ---------------------------------------------------------------------------------------------------------------Other Pins -----------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C WQFN-40L 5x5 ----------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WQFN-40L 5x5, θJA -----------------------------------------------------------------------------------------------WQFN-40L 5x5, θJC ----------------------------------------------------------------------------------------------Junction Temperature ---------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -----------------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Model) --------------------------------------------------------------------------------------- Recommended Operating Conditions −0.3V to 6.5V −0.3V to 6V −0.3V to 0.3V −0.3V to 28V −0.3V to 6V −0.3V to 32V −8V to 38V −0.3V to 6V −2.5V to 7.5V −0.3V to 6V −5V to 7.5V −0.3V to (VCC + 0.3V) 3.63W 27.5°C/W 6°C/W 150°C 260°C −65°C to 150°C 2kV (Note 4) Supply Voltage, VCC, PVCC -----------------------------------------------------------------------------------Input Voltage, VIN -------------------------------------------------------------------------------------------------Junction Temperature Range ------------------------------------------------------------------------------------Ambient Temperature Range ------------------------------------------------------------------------------------- 4.5V to 5.5V 4.5V to 26V −40°C to 125°C −40°C to 85°C Electrical Characteristics (VCC = 5V, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Input Power Supply Supply Current IVCC EN = 3V, Not Switching -- 12 -- mA Shutdown Current ISHDN EN = 0V -- -- 5 A PVCC Supply Voltage VPVCC 4.5 -- 5.5 V PVCC Supply Current IPVCC -- 120 -- A VBOOTx = 5V, Not Switching Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Parameter Symbol Test Conditions Min Typ Max Unit Driver Power On Reset (Driver POR) Driver POR Threshold Driver POR Hysteresis VPOR_r PVCC POR Rising -- 3.85 4.1 VPOR_f PVCC POR Falling 3.4 3.65 -- -- 200 -- mV V FB = 1.0000 1.5500 (No Load, CCM Mode ) 0.5 0 0.5 %SVID V FB = 0.8000 1.0000 5 0 5 V FB = 0.3000 0.8000 8 0 8 V FB = 0.2500 0.3000 80 0 80 IRGND EN = 3V, Not Switching -- 200 -- A SR SetVID Fast 7.5 12 -- mV/s -- -- 2 mV V VPOR_Hys Reference and DAC DC Accuracy VFB mV RGND Current RGND Current Slew Rate Dynamic VID Slew Rate Error Amplifier Input Offset VEAOFS DC Gain ADC R L = 47k 70 80 -- dB Gain-Bandwidth Product GBW C LOAD = 5pF -- 10 -- MHz Output Voltage Range VCOMP 0.3 -- 3.6 V Maximum Source Current IEA, SRC 1 -- -- mA Maximum Sink Current IEA, SNK 1 -- -- mA 0.2 -- 0.2 mV 97 -- 103 % 194 -- 206 % Current Sense Amplifier Input Offset Voltage VOSCS Current Mirror Gain for CORE AMIRROR, VDD Current Mirror Gain for NB AMIRROR, VDDNB Internal Sum Current Ai, VDD Sense DC Gain for CORE VDD Controller -- 0.4 -- V/V Internal Sum Current Sense DC Gain for NB Ai, VDDNB VDDNB Controller -- 0.8 -- V/V Maximum Source Current ICS, SRC 0 < V FB < 2.35 100 -- -- A Maximum Sink Current ICS, SNK 0 < V FB < 2.35 10 -- -- A VZCD_TH V ZCD_TH = GND VPHASEx -- 1 -- mV Zero Current Detection Zero Current Detection Threshold Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 15 RT8179B Parameter Symbol Test Conditions Min Typ Max Unit -- 0.5 -- V Ton Setting TONSETx Pin Minimum Voltage VTON, MIN TONSETx Ton TON IRTON = 80A, VFB = 1.1V 270 305 340 ns TONSETx Input Current Range IRTON VFB = 1.1V 25 -- 280 A Minimum TOFF TOFF -- 250 -- ns 1.97 2 2.03 V 0.61 0.64 0.67 V 800 -- -- A IBIAS IBIAS Pin Voltage VIBIAS RIBIAS = 100k V064 Reference Voltage Output V064 Sink Current Capability IV064, SNK Source Current Capability IV064, SRC -- -- 100 A VFB Limit VFB, LIMIT 0 -- 2.35 V OFS Update Rate FOFS -- 50 -- kHz Board Offset Resolution VOFS -- 6.25 -- mV Logic-High VIH_EN 2 -- -- Logic-Low VIL_EN -- -- 0.8 ILEK_EN 1 -- 1 V064 = 0.64V Board OFSx Logic Inputs EN Input Voltage Leakage Current of EN V A Logic-High VIH_SVI Respect to VDDIO 70 -- 100 Logic-Low VIL_SVI Respect to VDDIO 0 -- 35 VHYS_SVI Respect to VDDIO 10 -- -- % Under Voltage Lockout Threshold VUVLO VCC Falling edge 4 4.2 4.4 V Under Voltage Lockout Hysteresis VUVLO -- 100 -- mV Under Voltage Lockout Delay TUVLO -- 3 -- s Over Voltage Protection Threshold VOVP VID Higher than 0.9V VID + 275 VID + 325 VID + 375 mV VID Lower than 0.9V 1175 1225 1275 -- 1 -- s 575 500 425 mV -- 3 -- s SVC, SVD, SVT, PWROK Voltage SVC, SVD, SVT, PWROK Hysteresis % Protection VCC Rising above UVLO Threshold Over Voltage Protection Delay TOVP VSEN Rising above Threshold Under Voltage Protection Threshold VUVP Respect to VID Voltage Under Voltage Protection Delay TUVP VSEN Falling below Threshold Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 16 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Parameter Symbol Negative Voltage Protection Threshold VNV Per Phase OCP Threshold IOCP_PERPHASE Delay of Per Phase OCP TPHOCP OCP_SPIKE Threshold IOCP_SPIKE OCP_SPIKE Action Delay TOCPSPIKE _ACTION_DLY OCP_TDC Action Delay Test Conditions IISENxN Per-Phase OCP Threshold. DCR = 1.1m, RCS = 680, RIMON = 52.3k TOCPTDC _ACTION_DLY Min Typ Max Unit -- 0 -- mV 8 10 12 A -- 1 -- s 27 30 33 A 6 -- 12 s 12 -- 24 s 0 -- 0.2 V 2 -- -- s OCP_L, PGOOD and PGOODA Output Low Voltage at OCP_L VOCP_L OCP_L Assertion Time TOCP_L Output Low Voltage at PGOOD, PGOODA VPGOOD, VPGOODA , IPGOOD = 4mA, IPGOODA = 4mA 0 -- 0.2 V PGOOD and PGOODA Threshold Voltage VTH_PGOOD VTH_PGOODA Respect to BOOT VID -- 300 -- mV PGOOD and PGOODA Delay Time TPGOOD TPGOODA VSEN = BOOT VID to PGOOD/PGOODA High 70 100 130 s Maximum Reported Current (FFh = OCP) -- 100 -- %IDD_SP IKE_OCP Minimum Reported Current (00h) -- 0 -- %IDD_SP IKE_OCP IDDSpike Current Accuracy -- -- 3 % Maximum Reported Voltage (0_00h) -- 3.15 -- V Minimum Reported Voltage (1_F8h) -- 0 -- V Voltage Accuracy 2 -- 2 LSB IOCP_L = 4mA Current Report Voltage Report Switching Time UGATEx Rise Time tUGATEr 3nF Load -- 8 -- ns UGATEx Fall Time tUGATEf 3nF Load -- 8 -- ns LGATEx Rise Time tLGATEr 3nF Load -- 8 -- ns LGATEx Fall Time tLGATEf 3nF Load -- 4 -- ns Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 17 RT8179B Parameter Symbol Test Conditions Min Typ Max Unit UGATEx Turn-On Propagation Delay tPDHU Outputs Unloaded -- 20 -- ns LGATEx Turn-On Propagation Delay tPDHL Outputs Unloaded -- 20 -- ns UGATEx Driver Source Resistance RUGATEsr 100mA Source Current -- 1 -- UGATEx Driver Source Current IUGATEsr VUGATE VPHASE = 2.5V -- 2 -- A UGATEx Driver Sink Resistance RUGATEsk 100mA Sink Current -- 1 -- UGATEx Driver Sink Current IUGATEsk VUGATE VPHASE = 2.5V -- 2 -- A LGATEx Driver Source Resistance RLGATEsr 100mA Source Current -- 1 -- LGATEx Driver Source Current ILGATEsr VLGATE = 2.5V -- 2 -- A LGATEx Driver Sink Resistance RLGATEsk 100mA Sink Current -- 0.5 -- LGATEx Driver Sink Current ILGATEsk VLGATE = 2.5V -- 4 -- A f SVC (Note 5) 0.1 -- 20 MHz Output SVI2 Bus SVC Frequency Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Min. SVC frequency defined in electrical spec. is related with different application. As min. SVC < 1MHz, VR can't support telemetry reporting function. As min. SVC < 400kHz, VR can't support telemetry reporting function and VOTF complete function. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 18 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 DS8179B-04 January 2015 Copyright © 2015 Richtek Technology Corporation. All rights reserved. MLCC : 22µF x 12 POSCAP : 330µF x 3 LOAD VVDDNB VSS_SENSE 10 1k 4.7 10 0.1µF 360 0.47µF RNTC 100k 1 VIN 10k 270pF RNTC 13.15k 100k 23.2k 6.8k 3.3nF 1.74k 4.7 VCC5 0.1µF 0.1µF 97.6k 0 RCS 1k 0 0 2.2 5.1k 15pF RIMONA 19.31k RIMON 39.51k 150k VCC PVCC 20 IMONA IMON COMPA LGATEA PHASEA UGATEA 27 ISENA1N 28 ISENA1P 36 35 34 33 BOOTA 25 FBA 8 RGND 24 26 VSENA 11 9 29 EN 10 V064 12 23 16 7 5 1 38 39 ISEN1N 3 ISEN1P 4 LGATE PHASE UGATE 40 BOOT FB 6 COMP VSEN 0 0 2.2 RCS 1k 0.1µF 78.7k 1.74k 15pF 0 4.7k 10k 330pF VIN To CPU 4.7k VDDIO RIBIAS 100k 1µF 2.2 GND 41 (Exposed Pad) IBIAS SVT PGOODA 30 14 SVC 15 SVD PGOOD 31 13 OCP_L 21 VDDIO PWROK RT8179B 2 TONSET 32 TONSETA SET2 19 SET1 17 OFS 18 OFSA 22 37 0.1µF 2.2µF RTONNB 6.32k 10 0.1µF 0.1µF 5V 2.2µF 6.32k 29.4k VIN 210 270µF 1µH/7.5m 2.2 14k RTON 154k 110 8.45k 0.47µF 30.1k 3.16k 124k 20k 20k VVDDNB_SENSE Enable VIN VCC5 VCC5 VCC5 VCC5 5V 0.1µF 3.3nF 1 1.74k 360 LOAD VVDD POSCAP : 330µF x 3 10 MLCC : 22µF x 12 10 VSS_SENSE VVDD_SENSE 0.47µF 1µH/7.5m 10k 270µF 10k 3.3V RT8179B Typical Application Circuit is a registered trademark of Richtek Technology Corporation. www.richtek.com 19 RT8179B Typical Operating Characteristics CORE VR Power On from EN CORE VR Power Off from EN VVDD (500mV/Div) VVDD (500mV/Div) EN (4V/Div) EN (4V/Div) PGOOD (2V/Div) PGOOD (2V/Div) UGATE (30V/Div) Boot VID = 0.8V UGATE (30V/Div) Time (200μs/Div) Time (200μs/Div) CORE VR OCP_TDC CORE VR OCP_SPIKE I LOAD (10A/Div) I LOAD (20A/Div) OCP_L (2V/Div) OCP_L (2V/Div) PGOOD (2V/Div) PGOOD (2V/Div) UGATE (50V/Div) ILOAD = 10A to 25A UGATE (50V/Div) ILOAD = 15A to 40A Time (5ms/Div) Time (10μs/Div) CORE VR OVP and NVP CORE VR UVP VVDD (1V/Div) VVDD (1V/Div) PGOOD (2V/Div) PGOOD (2V/Div) UGATE (50V/Div) UGATE (50V/Div) LGATE (10V/Div) VID = 1.1V Time (20μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 20 Boot VID = 0.8V LGATE (10V/Div) VID = 1.1V Time (10μs/Div) is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B CORE VR Dynamic VID Up CORE VR Dynamic VID Up VVDD (1V/Div) I LOAD (3A/Div) VVDD (1V/Div) I LOAD (15A/Div) SVD (2V/Div) SVD (2V/Div) SVT (2V/Div) VID = 0.4V to 1V, ILOAD = 1.5A SVT (2V/Div) VID = 1V to 1.06875V, ILOAD = 7.5A Time (20μs/Div) Time (20μs/Div) CORE VR Dynamic VID Up CORE VR Dynamic VID Up VVDD (1V/Div) I LOAD (15A/Div) VVDD (1V/Div) I LOAD (15A/Div) SVD (2V/Div) SVD (2V/Div) SVT (2V/Div) VID = 1V to 1.1V, ILOAD = 7.5A SVT (2V/Div) VID = 1V to 1.2V, ILOAD = 7.5A Time (20μs/Div) Time (20μs/Div) CORE VR Dynamic VID Up CORE VR Load Transient VVDD (1V/Div) I LOAD (15A/Div) VVDD (30mV/Div) SVD (2V/Div) SVT (2V/Div) VID = 1V to 1.4V, ILOAD = 7.5A Time (20μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 I LOAD (10A/Div) fLOAD = 10kHz, ILOAD = 7A to 21A Time (5μs/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 21 RT8179B NB VR Power On from EN CORE VR Load Transient VVDD (30mV/Div) V VDDNB (500mV/Div) EN (4V/Div) PGOODA (2V/Div) I LOAD (10A/Div) fLOAD = 10kHz, ILOAD = 21A to 7A UGATEA (30V/Div) Time (5μs/Div) Time (200μs/Div) NB VR Power Off from EN NB VR OCP_TDC V VDDNB (500mV/Div) I LOAD (10A/Div) OCP_L (2V/Div) EN (4V/Div) PGOODA (2V/Div) UGATEA (30V/Div) Boot VID = 0.8V PGOODA (2V/Div) UGATEA (50V/Div) Time (5ms/Div) NB VR OCP_SPIKE NB VR OVP and NVP V VDDNB (1V/Div) PGOODA (2V/Div) PGOODA (2V/Div) UGATEA (50V/Div) ILOAD = 15A to 40A Time (10μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 22 ILOAD = 10A to 25A Time (200μs/Div) I LOAD (20A/Div) OCP_L (2V/Div) UGATEA (50V/Div) Boot VID = 0.8V LGATEA (10V/Div) VID = 1.1V Time (20μs/Div) is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B NB VR UVP NB VR Dynamic VID Up V VDDNB (1V/Div) I LOAD (3A/Div) V VDDNB (1V/Div) PGOODA (2V/Div) SVD (2V/Div) UGATEA (50V/Div) LGATEA (10V/Div) VID = 1.1V SVT (2V/Div) Time (10μs/Div) Time (20μs/Div) NB VR Dynamic VID Up NB VR Dynamic VID Up V VDDNB (1V/Div) I LOAD (13A/Div) V VDDNB (1V/Div) I LOAD (13A/Div) SVD (2V/Div) SVD (2V/Div) SVT (2V/Div) VID = 0.4V to 1V, ILOAD = 1.3A VID = 1V to 1.06875V, ILOAD = 6.5A SVT (2V/Div) VID = 1V to 1.1V, ILOAD = 6.5A Time (20μs/Div) Time (20μs/Div) NB VR Dynamic VID Up NB VR Dynamic VID Up V VDDNB (1V/Div) I LOAD (13A/Div) V VDDNB (1V/Div) I LOAD (13A/Div) SVD (2V/Div) SVD (2V/Div) SVT (2V/Div) VID = 1V to 1.2V, ILOAD = 6.5A Time (20μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 SVT (2V/Div) VID = 1V to 1.4V, ILOAD = 6.5A Time (20μs/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 23 RT8179B NB VR Load Transient V VDDNB (30mV/Div) I LOAD (10A/Div) V VDDNB (30mV/Div) fLOAD = 10kHz, ILOAD = 7A to 17A Time (5μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 24 NB VR Load Transient I LOAD (10A/Div) fLOAD = 10kHz, ILOAD = 17A to 7A Time (5μs/Div) is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Application Information Power Ready (POR) Detection During start-up, the RT8179B will detect the voltage at the voltage input pins : VCC, PVCC and EN. When VCC > 4.2V and PVCC > 3.85V, the IC will recognize the power state of system to be ready (POR = high) and wait for enable command at the EN pin. After POR = high and VEN VCC + 4.2V PVCC + 3.85V EN CMP POR + 2V CMP CMP Chip EN - Figure 1. Power Ready (POR) Detection Precise Reference Current Generation The RT8179B includes complicated analog circuits inside the controller. The IC needs very precise reference voltage/ current to drive these analog circuits. The IC will auto generate a 2V voltage source at the IBIAS pin, and a 100kΩ resistor is required to be connected between IBIAS and analog ground, as shown in Figure 2. Through this connection, the IC will generate a 20μA current from the IBIAS pin to analog ground, and this 20μA current will be mirrored for internal using. Note that other type of connection or other values of resistance applied at the IBIAS pin may cause functional failure, such as slew rate control, OFS accuracy, etc. In other words, the IBIAS pin Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 Current Mirror 2V + - > 2V, the IC will enter start-up sequence for both VDD rail and VDDNB rail. If the voltage at the pins of VCC and EN drop below low threshold, the IC will enter power down sequence and all the functions will be disabled. Normally, connecting system power to the EN pin is recommended. The SVID will be ready in 2ms (max) after the chip has been enabled. All the protection latches (OVP, OCP, UVP) will be cleared only after POR = low. The condition of VEN = low will not clear these latches. can only be connected with a 100kΩ resistor to GND. The resistance accuracy of this resistor is recommended to be 1% or higher. + - IBIAS 100k Figure 2. IBIAS Setting Boot VID When EN goes high, both VDD and VDDNB output begin to soft-start to the boot VID in CCM. Table 7 shows the Boot VID setting. The Boot VID is determined by the SVC and SVD input states at EN rising edge and it is stored in the internal register. The digital soft-start circuit ramps up the reference voltage at a controlled slew rate to reduce inrush current during start up. When all the output voltages are above power good threshold (300mV below Boot VID) at the end of soft-start, the controller asserts power good after a time delay. Table 7. 2-Bit Boot VID Code Initial Startup VID (Boot VID) SVC SVD VDD/VDDNB Output Voltage (V) 0 0 1.1 0 1 1.0 1 0 0.9 1 1 0.8 Start-Up Sequence After EN goes high, the RT8179B starts up and operates according to the initial settings. Figure 3 shows the simplified sequence timing diagram. The detailed operation is described in the following. is a registered trademark of Richtek Technology Corporation. www.richtek.com 25 RT8179B T0 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 PVCC, VCC SVID Send Byte SVC SVID Send Byte SVD VOTF Complete VOTF Complete SVT EN PWROK CCM Boot VID CCM VDD/ VDDNB VID CCM Boot VID CCM CCM VID CCM CCM PGOOD/ PGOODA Figure 3. Simplified Sequence Timing Diagram Description of Figure 3 : T0 : The RT8179B waits for VCC and PVCC POR. T1 : The SVC pin and SVD pin set the Boot VID. Boot VID is latched at EN rising edge. SVT is driven high by the RT8179B. T2 : The enable signal goes high and all output voltages ramp up to the Boot VID in CCM. The soft-start slew rate is 3mV/μs. T3 : All output voltages are within the regulation limits and the PGOOD and PGOODA signal goes high. T4 : The PWROK pin goes high and the SVI2 interface starts running. The RT8179B waits for SVID command from processor. T5 : A valid SVID command transaction occurs between the processor and the RT8179B. T7 : The PWROK pin goes low and the SVI2 interface stops running. All output voltages go back to the Boot VID in CCM. T8 : The PWROK pin goes high again and the SVI2 interface starts running. The RT8179B waits for SVID command from processor. T9 : A valid SVID command transaction occurs between the processor and the RT8179B. T10 : The RT8179B starts VID-on-the-fly transition according to the received SVID command and send a VOTF Complete if the VID reaches target VID. T11 : The enable signal goes low and all output voltages enter soft-shutdown mode. T6 : The RT8179B starts VOTF (VID-on-the-fly) transition according to the received SVID command and send a VOTF Complete if the VID reaches target VID. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 26 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Power Down Sequence SVI2 Wire Protocol If the voltage at EN pin falls below the enable falling threshold, the controller is disabled. The voltage at the PGOOD and PGOODA pin will immediately go low at the loss of enable signal at the EN pin and the controller executes soft-shutdown operation. The internal digital circuit ramps down the reference voltage at the same slew rate as that of in soft-start, making VDD and VDDNB output voltages gradually decrease in CCM. Each of the controller channels stops switching when the voltage at the voltage sense pin VSEN/VSENA, cross about 0.2V. The Boot VID information stored in the internal register is cleared at IC POR. This event forces the RT8179B to check the SVC and SVD inputs for a new boot VID when the EN voltage goes high again. The RT8179B complies with AMD's Voltage Regulator Specification, which defines the Serial VID Interface 2 (SVI2) protocol. With SVI2 protocol, the processor directly controls the reference voltage level of each individual controller channel and determines which controller operates in power saving mode. The SVI2 interface is a three-wire bus that connects a single master to one or more slaves. The master initiates and terminates SVI2 transactions and drives the clock, SVC, and the data, SVD, during a transaction. The slave drives the telemetry, SVT during a transaction. The AMD processor is always the master. The voltage regulator controller (RT8179B) is always the slave. The RT8179B receives the SVID code and acts accordingly. The SVI protocol supports 20MHz high speed mode I2C, which is based on SVD data packet. Table 8 shows the SVD data packet. A SVD packet consists of a “Start” signal, three data bytes after each byte, and a “Stop” signal. The 8-bit serial VID codes are listed in Table1. After the RT8179B has received the stop sequence, it decodes the received serial VID code and executes the command. The controller has the ability to sample and report voltage and current for the VDD and VDDNB domains. The controller reports this telemetry serially over the SVT wire which is clocked by the processor driven SVC. A bit TFN at SVD packet along with the VDD and VDDNB domain selector bits are used by the processor to change the telemetry functionality. The telemetry bit definition is listed in Figure 4. The detailed SVI2 specification is outlined in the AMD Voltage Regulator and Voltage Regulator Module (VRM) and Serial VID Interface 2.0 (SVI2) Specification. PGOOD and PGOODA The PGOOD and PGOODA are open-drain logic outputs. The two pins provide the power good signal when VDD and VDDNB output voltage are within the regulation limits and no protection is triggered. These pins are typically tied to 3.3V or 5V power source through a pull-high resistor. During shutdown state (EN = low) and the softstart period, the PGOOD and PGOODA voltages are pulled low. After a successful soft-start and VDD and VDDNB output voltages are within the regulation limits, the PGOOD and PGOODA are released high individually. The voltages at the PGOOD pin and PGOODA pin are pulled low individually during normal operation when any of the following events occurs: over voltage protection, under voltage protection, over current protection, and logic low EN voltage. If one rail triggers protection, another rail's PGOOD will be pull low after 5μs delay. Table 8. SVD Data Packet Bit Time Description 1:5 8 Always 11000b VDD domain selector bit, if set then the following two data bytes contain the VID for VDD, the PSI state for VDD, and the load line slope trim and offset trim state for VDD. VDDNB domain selector bit, if set then the following two data bytes contain the VID for VDDNB, the PSI state for VDDNB, and the load line slope trim and offset trim state for VDDNB. Always 0b 10 PSI0_L 6 7 11 : 17 19 VID Code bits [7:1] VID Code bit [0] Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 27 RT8179B Bit Time Description 20 PSI1_L 21 TFN (Telemetry Functionality) 22 : 24 Load Line Slope Trim [2:0] 25 : 26 Offset Trim [1:0] Voltage and Current Mode Selection Bit Time…… START 1 2 3 VDDNB Voltage Bit in Voltage Only Mode; Current Bit in Voltage and Current Mode VDD Voltage Bits 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 STOP SVC SVT Figure 4. Telemetry Bit Definition PWROK and SVI2 Operation VID on-the-Fly Transition The PWROK pin is an input pin, which is connected to After the RT8179B has received a valid SVID code, it enters CCM mode and executes the VID on-the-fly transition by stepping up/down the reference voltage of the required controller channel(s) in a controlled slew rate, hence, allowing the output voltage(s) to ramp up/down to the target VID. The output voltage slew rate during the VID on-thefly transition is faster than that in a soft-start/soft-shutdown operation. If the new VID level is higher than the current VID level, the controller begins stepping up the reference voltage with a typical slew rate of 12.5mV/μs upward to the target VID level. If the new level is lower than the current VID level, the controller begins stepping down the reference voltage with a typical slew rate of −12.5mV/μs downward to the target VID level. the global power good signal from the platform. Logic high at this pin enables the SVI2 interface, allowing data transaction between processor and the RT8179B. Once the RT8179B receives a valid SVID code, it decodes the information from processor to determine which output plane is going to move to the target VID. The internal DAC then steps the reference voltage in a controlled slew rate, making the output voltage shift to the required new VID. Depending on the SVID code, more than one controller channels can be targeted simultaneously in the VID transition. For example, VDD and VDDNB voltages can ramp up/down at the same time. If the PWROK input goes low during normal operation, the SVI2 protocol stops running. The RT8179B immediately drives SVT high and modifies all output voltages back to the boot VID, which is stored in the internal register right after the controller is enabled. The controller does not read SVD and SVC inputs after the loss of PWROK. If the PWROK input goes high again, the SVI2 protocol resumes running. The RT8179B then waits to decode the SVID command from processor for a new VID and acts as previously described. The SVI2 protocol only runs when the PWROK input goes high after the voltage at the EN pin goes high; otherwise, the RT8179B will not soft-start due to incorrect signal sequence. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 28 During the VID on-the-fly transition, the RT8179B will force the controller channel to operate in CCM mode. If the controller channel operates in the power-saving mode prior to the VID on-the-fly transition, it will be in CCM mode during the transition and then back to the power saving mode at the end of the transition. The voltage at the PGOOD pin and PGOODA pin will keep high during the VID on-the-fly transition. The RT8179B checks the output voltage for voltage-related protections and send a VOTF complete at the end of VID on-the-fly transition. In the event of receiving a VID off code, the RT8179B steps the reference voltage of required controller channel down to zero, hence making the required output voltage decrease to zero. The voltage at the PGOOD pin and PGOODA pin will remain high since the VID code is valid. is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Operation Mode Transition SET1 and SET2 Pin Setting The RT8179B supports operation mode transition function in VDD and VDDNB controller for the PSI[x]_L and command from AMD processor. Referring to Table 8, the PSI[x]_L bit in the SVI2 protocol controls the operating mode of the RT8179B controller channels. The default operation mode of VDD and VDDNB controller is CCM. When the VDD controller receives PSI0_L = 0 and PSI1_L = 1, the VDD controller enters diode emulation mode. When the VDD controller receives PSI0_L = 0 and PSI1_L = 0, the VDD controller remains diode emulation mode. In reverse, the VDD controller goes back to CCM operation upon receiving PSI0_L = 1 and PSI1_L = 0 or 1. When the VDDNB controller receives PSI0_L = 0 and PSI1_L = 1, it enters diode emulation mode, when the VDDNB controller receives PSI0_L = 0 and PSI1_L = 0, it remains diode emulation mode. When the VDDNB controller goes back to CCM operation after receiving PSI0_L = 1 and PSI1_L = 0 or 1. The RT8179B provides the SET1 pin for platform users to set the VDD and VDDNB controller OCP_TDC threshold, DVIDx compensation bit 1 and internal ramp amplitude (RSET & RSETA), and the SET2 pin to set VDD and VDDNB controller OCP trigger delay time (OCPTRGDELAY), DVIDx compensation bit 0, external offset function, VDDNB zero load line and quick response threshold (QRTH & QRTHA). To set these pin, platform designers should use resistive voltage divider on these pins, refer to Figure 6 and Figure 7. The voltage at the SET1 and SET2 pin is RSET1,D (1) VSET1 VCC RSET1,U RSET1,D Table 9. VDD and VDDNB VR Power State PSI0_L : PSI1_L 00 01 10 or 11 Mode DEM DEM CCM Differential Remote Sense Setting The VDD and VDDNB controllers have differential, remotesense inputs to eliminate the effects of voltage drops along the PC board traces, processor internal power routes and socket contacts. The processor contains on-die sense pins, VDD_SENSE, VDDNB_SENSE and VSS_SENSE. Connect RGND to VSS_SENSE. For VDD controller, connect FB to VDD_SENSE with a resistor to build the negative input path of the error amplifier. Connect FBA to VDDNB_SENSE with a resistor using the same way in VDD controller. Connect VSS_SENSE to RGND using separate trace as shown in Figure 5. The precision reference voltages refer to RGND for accurate remote sensing. Processor FB FBA RGND RSET2,D RSET2,U RSET2,D (2) The ADC monitors and decodes the voltage at this pin only once after power up. After ADC decoding (only once), a 40μA current (when VCC = 5V) will be generated at the SET1 and SET2 pin for internal using. That is the voltage at the SET1 and SET2 pin is VSET1 40A RSET1,U RSET1,D RSET1,U RSET1,D (3) VSET2 40A RSET2,U RSET2,D RSET2,U RSET2,D (4) From equation (1) to equation (4) and Table 2 to Table 5, platform users can set the OCP_TDC threshold, OCP trigger delay, internal ramp amplitude, DVIDx compensation parameter, external offset function, VDDNB zero load-line setting and quick response threshold for VDD and VDDNB controller. OCPTDCx DVIDx Compensation 40µA (VCC = 5V) RSETx VCC ADC 2.24V VSET1 VDD_SENSE VDDNB_SENSE VDD Controller VSET2 VCC RGND VDD NB Controller VSS_SENSE SET1 Register VSET1 RSET1,U SET1 RSET1,D RT8179B Figure 6. SET1 Pin Setting Figure 5. Differential Remote Voltage Sense Connection Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 29 RT8179B Droop Setting DVIDx Compensation and VDDNB zero LL OCPTR GDELAY It's very easy to achieve Adaptive Voltage Positioning (AVP) by properly setting the error amplifier gain due to the native droop characteristics as shown in Figure 9. This target is to have 40µA (VCC = 5V) QRTHx OFSx VCC ADC 2.24V VSET2 RSET2,U VVDD = VDAC,VDD − ILOAD x RDROOP RSET2,D Then solving the switching condition VCOMP2 = VCS in Figure 8 yields the desired error amplifier gain as SET2 SET2 Register VSET2 RT8179B GI A V R2 R1 RDROOP Figure 7. SET2 Pin Setting VDD Controller GI Loop Control The VDD controller adopts Richtek's proprietary G-NAVPTM topology. G-NAVPTM is based on the finite gain peak current mode with CCRCOT (Constant Current Ripple Constant On-Time) topology. The output voltage, VVDD will decrease with increasing output load current. The control loop consists of PWM modulators with power stages, current sense amplifiers and an error amplifier as shown in Figure 8. Similar to the peak current mode control with finite compensator gain, the HS_FET on-time is determined by CCRCOT on-time generator. When load current increases, VCS increases, the steady state COMP voltage also increases and induces VVDD to decrease, thus achieving AVP. A near-DC offset canceling is added to the output of EA to eliminate the inherent output offset of finite gain peak current mode controller. COMP2 + CMP - VIN CCRCOT PWM Logic HS_FET VVDD L RSENSE Driver RX CX RC LS_FET 0.4 x1 VCS + - Offset Canceling IMON + EA + C ISEN1P RCS ISEN1N RIMON V064 C2 C1 COMP FB RGND R2 R1 VVDD_SENSE VSS_SENSE VDAC,VDD Figure 8. VDD Controller : Simplified Schematic for Droop and Remote Sense in CCM Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 30 (5) (6) RSENSE RIMON 4 RCS 10 (7) where GI is the internal current sense amplifier gain. RSENSE is the current sense resistor. If no external sense resistor present, it is the equivalent resistance of the inductor. RDROOP is the equivalent load-line resistance as well as the desired static output impedance. VVDD AV2 > AV1 AV2 AV1 0 Load Current Figure 9. VDD Controller : Error Amplifier gain (AV) Influence on VVDD Accuracy Loop Compensation Optimized compensation of the VDD controller allows for best possible load step response of the regulator's output. A type-I compensator with one pole and one zero is adequate for proper compensation. Figure 10 shows the compensation circuit. Previous design procedure shows how to select the resistive feedback components for the error amplifier gain. Next, C1 and C2 must be calculated for compensation. The target is to achieve constant resistive output impedance over the widest possible frequency range. The pole frequency of the compensator must be set to compensate the output capacitor ESR zero : 1 fP (8) 2 C RC is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Where C is the capacitance of output capacitor, and RC is the ESR of output capacitor. C2 can be calculated as follows : C RC (9) C2 R2 The zero of compensator has to be placed at half of the switching frequency to filter the switching related noise. Such that, C1 1 R1 fSW (10) COMP C1 R2 R1 VVDD_SENSE FB + EA + C2 RGND VSS_SENSE VDAC, VDD Figure 10. VDD Controller : Compensation Circuit On-time translates only roughly to switching frequencies. For better efficiency of the given load range, the maximum switching frequency is suggested to be : fSW(MAX) VDAC(MAX) ILOAD(MAX) DCRL RON_LS-FET RDROOP VIN(MAX) ILOAD(MAX) RON_LS-FET RON_HS-FET TON TD TON, VAR ILOAD(MAX) RON_LS-FET TD (13) Where fS(MAX) is the maximum switching frequency, TD is the driver dead time, TON,VAR is the TON variation value. VDAC(MAX) is the Maximum VDAC of application, VIN(MAX) is the Maximum application Input voltage, ILOAD(MAX) is the maximum load of application, R ON_LS-FET is the onresistance of low side FET RDS(ON), RON_HS-FET is the of resistance of high side FET RDS(ON) , DCRL is the equivalent resistance of the inductor, and RDROOP is the load-line setting. CCRCOT On-Time Computer TON Setting High frequency operation optimizes the application for the smaller component size, trading off efficiency due to higher switching losses. This may be acceptable in ultra portable devices where the load currents are lower and the controller is powered from a lower voltage supply. Low frequency operation offers the best overall efficiency at the expense of component size and board space. Figure 11 shows the On-Time setting Circuit. Connect a resistor (RTON) between VIN and TONSET to set the on-time of UGATE : 24.4 1012 RTON (11) tON (0.5V VDAC 1.8V) VIN VDAC,VDD where tON is the UGATE turn-on period, VIN is Input voltage of the VDD controller, and VDAC is the DAC voltage. When VDAC is larger than 1.8V, the equivalent switching frequency may be over 500kHz, and this too fast switching frequency is unacceptable. Therefore, the VDD controller implements a pseudo constant frequency technology to avoid this disadvantage of CCRCOT topology. When VDAC is larger than 1.8V, the on-time equation will be modified to : t ON (VDAC 1.8V) 13.55 10 RTON VDAC,VDD VIN VDAC,VDD (12) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 RTON VDAC R1 VIN C1 On-Time Figure 11. VDD Controller : On-Time Setting with RC Filter Current Sense Setting The current sense topology of the VDD controller is continuous inductor current sensing. Therefore, the controller has less noise sensitive. Low offset amplifiers are used for loop control and over current detection. The ISEN1P and ISEN1N pins denote the positive and negative input of the current sense amplifier. Users can either use a current sense resistor or the inductor's DCRL for current sensing. Using the inductor's DCRL allows higher efficiency as shown in Figure 12. VVDD IL L DCRL RX ISEN1N + - 12 TONSET CX ISEN1P ISEN1N RCS Figure 12. VDD Controller : Lossless Inductor Sensing is a registered trademark of Richtek Technology Corporation. www.richtek.com 31 RT8179B In order to optimize transient performance, RX and CX must be set according to the equation below : L R C (14) X X DCRL Then the proportion between the phase current, IL, and the sensed current, ISEN1N, is driven by the value of the effective sense resistance, RCS, and the DCRL of the inductor. The resistance value of RCS is limited by the internal circuitry. The recommended value is from 500Ω to 1.2kΩ. DCRL (15) ISEN1N IL RCS Considering the inductance tolerance, the resistor RX has to be tuned on board by examining the transient voltage. If the output voltage transient has an initial dip below the minimum load-line requirement and the response time is too fast causing a ring back, the value of resistance should be increased. Vice versa, with a high resistance, the output voltage transient has only a small initial dip with a slow response time. The resistor RCS determines PHOCP threshold. IL,PERPHASE(MAX) RCS DCRL 1 = 10A RCS 8 IL,PERPHASE(MAX) DCRL 8 10A (16) (17) The controller will turn off all high side/low side MOSFETs to protect CPU if the per-phase over current protection is triggered. Initial Offset and External Offset (Over Clocking Offset Function) The VDD controller features over clocking offset function which provides the possibility of wide range offset of output voltage. The offset function can be implemented through the SVI interface. When the OFS pin voltage < 0.3V at EN rising edge, the initial offset is disabled. The external offset function can be implemented by the SET2 pin setting. For example, referring to Table 10, when the both rail external offset functions are enabled, the output voltage is : VVDD VDAC,VDD ILOAD x RDROOP + VExternal _ OFS Using current sense resistor in series with the inductor can have better accuracy, but the efficiency is a trade-off. Considering the equivalent inductance (LESL) of the current sense resistor, an RC filter is recommended. The RC filter calculation method is similar to the above mentioned inductor equivalent resistance sensing method. VInitial_OFS is the initial offset voltage set by SVI interface, and the external offset voltage, VExternal_OFS is set by supplying a voltage into OFS pin. Per-Phase Over Current Protection It can be calculated as below : The VDD controller provides over current protection in each phase. Called Per-Phase Over Current Protection (PHOCP). The VDD controller senses inductor current IL, and PHOCP comparator compares sensed current with PHOCP threshold current, as shown in Figure 13. 1 I 8 SEN1N PHOCP trigger 10µA Current Mirror ISEN1N + VInitial _ OFS VExternal _ OFS = VOFS 1.2V Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 32 (19) If supplying 1.3V at OFS pin , it will achieve 100mV offset at the output. Connecting a filter capacitor between the OFS and GND pins is necessary. Designers can design the offset slew rate by properly setting the filter bandwidth. Table 10. External Offset Function Setting for VDD and VDDNB Controller Core_ NB_ OFFSET_ OFFSET_ EN EN 0 Figure 13. VDD Controller : Per-Phase OCP Setting (18) 1 Description 0 Disable external offset function. 1 Core rail external offset is set by OFS pin voltage, and NB rail external offset is set by OFSA pin voltage. is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Dynamic VID Enhancement Quick Response During a dynamic VID event, the charging (dynamic VID up) or discharging (dynamic VID down) current causes unwanted load line effect which degrades the settling time performance. The RT8179B will hold the inductor current to hold the load line during a dynamic VID event. The VDD controller will always enter CCM operation when VDD controller receives dynamic VID up and VDD controller will hold the operating state when VDD controller receives dynamic VID down. The RT8179B also has DVID compensation which can boost up the Dynamic VID slew rate and adjust the VID on-the-fly complete timing. The DVID compensation parameter can be selected by using the SET1 and SET2 pins to set the DVID compensation bits. The VDD controller utilizes a quick response feature to support heavy load current demand during instantaneous load transient. The VDD controller monitors the current of the VVDD_SENSE, and this current is mirrored to internal quick response circuit. At steady state, this mirrored current will not trigger a quick response. When the VVDD_SENSE voltage drops abruptly due to load apply transient, the mirrored current flowing into quick response circuit will also increase instantaneously. The QR threshold setting for VDD controller refers to Table 4. QRTH + CMP - + QR Pulse Generation Circuit VVDD_SENSE Ramp Amplitude Adjust In case of smooth transition into DEM, the CCM ramp amplitude should be designed properly. The RT8179B provides the SET1 pin for platform users to set the ramp amplitude of the VDD controller in CCM. Current Monitoring and Current Reporting The VDD controller provides current monitoring function via inductor current sensing. In G-NAVPTM technology, the output voltage is dependent on output current, and the current monitoring function is achieved by this characteristic of output voltage. The equivalent output current will be sensed from inductor current sensing and mirrored to the IMON pin. The resistor connected to the IMON pin determines voltage of the IMON output. DCRL VIMON = IL RIMON 0.64 RCS (20) Where IL is the phase current, RCS is the effective sense resistance, and RIMON is the current monitor current setting resistor. Note that the IMON pin cannot be monitored. The ADC circuit of the VDD controller monitors the voltage variation at the IMON pin from 0V to 3.19375V, and this voltage is decoded into digital format and stored into Output_Current register. The ADC divides 3.19375V into 511 levels, so LSB = 3.19375V / 511 = 6.25mV. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 Figure 14. VDD Controller : Quick Response Triggering Circuit When quick response is triggered, the quick response circuit will generate a quick response pulse. The pulse width of quick response is almost the same as tON. After generating a quick response pulse, the pulse is then applied to the on-time generating circuit, and the on-time will be overridden by the quick response pulse. Over Current Protection The RT8179B has dual OCP mechanism. The dual OCP mechanism has two types of thresholds. The first type, referred to as OCP-TDC, is a time and current based threshold. OCP-TDC should trip when the output current exceeds TDC by some percentage and for a period of time. This period of time is referred to as the trigger delay. The second type, referred to as OCP-SPIKE, is a current based threshold. OCP-SPIKE should trip when the cycleby-cycle output current exceeds IDDSPIKE by some percentage. If either mechanism trips, then the VDD controller asserts OCP_L and delays any further action. This delay is called an action delay. Refer to action delay time. After the action delay has expired and the VDD controller has allowed its current sense filter to settle out and the current has not decreased below the threshold, is a registered trademark of Richtek Technology Corporation. www.richtek.com 33 RT8179B then the VDD controller will turn off both high side MOSFETs and low side MOSFETs. Users can set OCP-SPIKE threshold, IL,SUM(SPIKE), by the current monitor resistor RIMON of the following equation : R IL,SUM(SPIKE) = 3.19375 0.64 CS DCRL RIMON (21) And set the OCP-TDC threshold, IL(TDC), refer to some percentage of OCP-SPIKE through Table 2. Under Voltage Lock Out (UVLO) During normal operation, if the voltage at the VCC pin drops below IC POR threshold, the VDD controller will trigger UVLO. The UVLO protection forces all high side MOSFETs and low side MOSFETs off by shutting down internal PWM logic drivers. A 3μs delay is used in UVLO detection circuit to prevent false trigger. VDDNB Controller Over Voltage Protection (OVP) Loop Control The over voltage protection circuit of the VDD controller monitors the output voltage via the VSEN pin after IC POR. When VID is lower than 0.9V, once VVSEN exceeds “0.9V + 325mV”, OVP is triggered and latched. When VID is larger than 0.9V, once V VSEN exceeds the internal reference by 325mV, OVP is triggered and latched. The VDD controller will try to turn on low side MOSFETs and turn off high side MOSFETs of the VDD controller to protect the CPU. When OVP is triggered by one rail, the other rail will also enter soft shut down sequence. A 1μs delay is used in OVP detection circuit to prevent false trigger. The VDDNB controller adopts Richtek's proprietary GNAVPTM topology. G-NAVPTM is based on the finite gain Under Voltage Protection (UVP) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 34 CCRCOT PWM Logic 0.4 VCS VVDDNB HS_FET L RSENSE Driver RX CX RC LS_FET x2 + - C ISENA1P ISENA1N RCS IMONA RIMONA Offset Canceling V064 COMPA FBA EA RGND + VDAC, VDDNB + The VDD controller implements under voltage protection of VVDD. If VVSEN is less than the internal reference by 500mV, the VDD controller will trigger UVP latch. The UVP latch will turn off both high side and low side MOSFETs. When UVP is triggered by one rail, the other rail will also enter soft shut down sequence. A 3μs delay is used in UVP detection circuit to prevent false trigger. VIN + CMP - During OVP latch state, the VDD controller also monitors the VSEN pin for negative voltage protection. Since the OVP latch continuously turns on all low side MOSFETs of the VDD controller, the VDD controller may suffer negative output voltage. As a consequence, when the VSEN voltage drops below 0V after triggering OVP, the VDD controller will trigger NVP to turn off all low side MOSFETs of the VDD controller while the high side MOSFETs remains off. After triggering NVP, if the output voltage rises above 0V, the OVP latch will restart to turn on all low side MOSFETs. The NVP function will be active only after OVP is triggered. Similar to the peak current mode control with finite compensator gain, the HS_FET on-time is determined by CCRCOT on-time generator. When load current increases, VCS increases, the steady state COMPA voltage also increases and induces VVDDNB to decrease, thus achieving AVP. A near-DC offset canceling is added to the output of EA to eliminate the inherent output offset of finite gain peak current mode controller. COMP2 Negative Voltage Protection (NVP) peak current mode with CCRCOT (Constant Current Ripple Constant On-Time) topology. The output voltage, VVDDNB will decrease with increasing output load current. The control loop consists of PWM modulators with power stages, current sense amplifiers and an error amplifier as shown in Figure 15. C2 R2 C1 R1 VVDDNB_SENSE VSS_SENSE Figure 15. VDDNB Controller : Simplified Schematic for Droop and Remote Sense in CCM is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Droop Setting It's very easy to achieve Adaptive Voltage Positioning (AVP) by properly setting the error amplifier gain due to the native droop characteristics as shown in Figure 16. This target is to have VVDDNB = VDAC,VDDNB − ILOAD x RDROOP (22) Then solving the switching condition VCOMP2 = VCS in Figure 15 yields the desired error amplifier gain as GI A V R2 R1 RDROOP where GI (23) RSENSE RIMON 8 RCS 10 C2 C x RC R2 (26) The zero of compensator has to be placed at half of the switching frequency to filter the switching related noise. Such that, 1 C1 (27) R1 fSW COMPA (24) EA + C2 C1 R2 R1 VVDDNB_SENSE FBA + where GI is the internal current sense amplifier gain. RSENSE is the current sense resistor. If no external sense resistor present, it is the equivalent resistance of the inductor. RDROOP is the equivalent load-line resistance as well as the desired static output impedance. RGND VSS_SENSE VDAC,VDDNB Figure 17. VDDNB Controller : Compensation Circuit TON Setting VVDDNB AV2 > AV1 AV2 AV1 0 Where C is the capacitance of output capacitor, and RC is the ESR of output capacitor. C2 can be calculated as follows : Load Current Figure 16. VDDNB Controller : Error Amplifier gain (AV) Influence on VVDDNB Accuracy Loop Compensation Optimized compensation of the VDDNB controller allows for best possible load step response of the regulator’s output. A type-I compensator with one pole and one zero is adequate for proper compensation. Figure 17 shows the compensation circuit. Previous design procedure shows how to select the resistive feedback components for the error amplifier gain. Next, C1 and C2 must be calculated for compensation. The target is to achieve constant resistive output impedance over the widest possible frequency range. The pole frequency of the compensator must be set to compensate the output capacitor ESR zero : 1 fP (25) 2 C RC Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 High frequency operation optimizes the application for the smaller component size, trading off efficiency due to higher switching losses. This may be acceptable in ultra portable devices where the load currents are lower and the controller is powered from a lower voltage supply. Low frequency operation offers the best overall efficiency at the expense of component size and board space. Figure 18 shows the On-Time setting Circuit. Connect a resistor (RTON) between VIN and TONSETA to set the on-time of UGATE : 24.4 1012 RTON (28) tON (0.5V VDAC 1.8V) VIN VDAC,VDDNB where tON is the UGATE turn-on period, VIN is Input voltage of the VDDNB controller, and VDAC,VDDNB is the DAC voltage. When VDAC,VDDNB is larger than 1.8V, the equivalent switching frequency may be over 500kHz, and this too fast switching frequency is unacceptable. Therefore, the VDDNB controller implements a pseudo constant frequency technology to avoid this disadvantage of CCRCOT topology. When VDAC,VDDNB is larger than 1.8V, the on-time equation will be modified to : tON (VDAC 1.8V) 12 13.55 10 RTON VDAC,VDDNB VIN VDAC,VDDNB (29) is a registered trademark of Richtek Technology Corporation. www.richtek.com 35 RT8179B On-time translates only roughly to switching frequencies. For better efficiency of the given load range, the maximum switching frequency is suggested to be : fSW(MAX) VDAC(MAX) ILOAD(MAX) DCRL RON_LS-FET RDROOP VIN(MAX) ILOAD(MAX) RON_LS-FET RON_HS-FET TON TD TON, VAR ILOAD(MAX) RON_LS-FET TD (30) Where fS(MAX) is the maximum switching frequency, TD is the driver dead time, TON,VAR is the TON variation value. VDAC(MAX) is the Maximum VDAC,VDDNB of application, V IN(MAX) is the Maximum application Input voltage, ILOAD(MAX) is the maximum load of application, RON_LS-FET is the on-resistance of low side FET RDS(ON) , RON_HS-FET is the on-resistance of high side FET RDS(ON), DCRL is the inductor equivalent resistance of the inductor, and RDROOP is the load-line setting. CCRCOT On-Time Computer TONSETA RTON R1 VIN C1 VDAC,VDDNB On-Time Figure 18. VDDNB Controller : On-Time Setting with RC Filter Current Sense Setting The current sense topology of the VDDNB controller is continuous inductor current sensing. Therefore, the controller has less sensitive noise. Low offset amplifiers are used for loop control and over current detection. The ISENA1P and ISENA1N pins denote the positive and negative input of the current sense amplifier. Users can either use a current sense resistor or the inductor's DCRL for current sensing. Using the inductor's DCRL allows higher efficiency as shown in Figure 19. IL L ISENA1N + - CX Considering the inductance tolerance, the resistor RX has to be tuned on board by examining the transient voltage. If the output voltage transient has an initial dip below the minimum load-line requirement and the response time is too fast causing a ring back, the value of resistance should be increased. Vice versa, with a high resistance, the output voltage transient has only a small initial dip with a slow response time. Using current sense resistor in series with the inductor can have better accuracy, but the efficiency is a trade-off. Considering the equivalent inductance (LESL) of the current sense resistor, an RC filter is recommended. The RC filter calculation method is similar to the above mentioned inductor equivalent resistance sensing method. Per-Phase Over Current Protection The VDDNB controller provides over current protection in each phase. Called Per-Phase Over Current Protection (PHOCP). The VDDNB controller senses inductor current IL, and PHOCP comparator compares sensed current with PHOCP threshold current, as shown in Figure 20. 1 I 8 SENA1N PHOCP trigger 10µA ISENA1P ISENA1N Then the proportion between the phase current, IL, and the sensed current, ISENA1N, is driven by the value of the effective sense resistance, RCS, and the DCRL of the inductor. The resistance value of RCS is limited by the internal circuitry. The recommended value is from 500Ω to 1.2kΩ. DCRL (32) ISENA1N IL RCS VVDDNB DCRL RX In order to optimize transient performance, RX and CX must be set according to the equation below : L R C (31) X X DCRL Current Mirror ISENA1N RCS Figure 20. VDDNB Controller : Per-Phase OCP Setting Figure 19. VDDNB Controller : Lossless Inductor Sensing Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 36 is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B The resistor RCS determines PHOCP threshold. IL,PERPHASE(MAX) RCS DCRL 1 = 10A RCS 8 IL,PERPHASE(MAX) DCRL 8 10A (33) (34) The controller will turn off all high side/low side MOSFETs to protect CPU if the per-phase over current protection is triggered. Initial Offset and External Offset (Over Clocking Offset Function) The VDDNB controller features over clocking offset function which provides the possibility of wide range offset of output voltage. The offset function can be implemented through the SVI interface. When the OFSA pin voltage < 0.3V at EN rising edge, the initial offset is disabled. The external offset function can be implemented by the SET2 pin setting. For example, referring to Table 10, when the both rail external offset functions are enabled, the output voltage is : VVDDNB VDAC,VDDNB ILOAD RDROOP + VExternal _ OFSA + VInitial _ OFSA (35) VInitial_OFSA is the initial offset voltage set by SVI interface, and the external offset voltage, VExternal_OFSA is set by supplying a voltage into OFSA pin. It can be calculated as below : VExternal _ OFSA = VOFSA 1.2V (36) If supplying 1.3V at OFSA pin, it will achieve 100mV offset at the output. Connecting a filter capacitor between the OFSA and GND pins is necessary. Designers can design the offset slew rate by properly setting the filter bandwidth. Dynamic VID Enhancement During a dynamic VID event, the charging (dynamic VID up) or discharging (dynamic VID down) current causes unwanted load line effect which degrades the settling time performance. The RT8179B will hold the inductor current to hold the load line during a dynamic VID event. The VDDNB controller will always enter CCM operation when VDDNB controller receives dynamic VID up and VDDNB controller will hold the operating state when VDDNB controller receives dynamic VID down. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 The RT8179B also has DVID compensation which can boost up the Dynamic VID slew rate and adjust the VID on-the-fly complete timing. The DVID compensation parameter can be selected by using the SET1 and SET2 pins to set the DVID compensation bits. Ramp Amplitude Adjust In case of smooth transition into DEM, the CCM ramp amplitude should be designed properly. The RT8179B provides the SET1 pin for platform users to set the ramp amplitude of the VDDNB controller in CCM. Current Monitoring and Current Reporting The VDDNB controller provides current monitoring function via inductor current sensing. In G-NAVPTM technology, the output voltage is dependent on output current, and the current monitoring function is achieved by this characteristic of output voltage. The equivalent output current will be sensed from inductor current sensing and mirrored to the IMONA pin. The resistor connected to the IMONA pin determines voltage of the IMONA output. DCRL (37) VIMONA = IL 2 RIMONA 0.64 RCS Where IL is the phase current, RCS is the effective sense resistance, and RIMONA is the current monitor current setting resistor. Note that the IMONA pin cannot be monitored. The ADC circuit of the VDDNB controller monitors the voltage variation at the IMONA pin from 0V to 3.19375V, and this voltage is decoded into digital format and stored into Output_Current register. The ADC divides 3.19375V into 511 levels, so LSB = 3.19375V / 511 = 6.25mV. Quick Response The VDDNB controller utilizes a quick response feature to support heavy load current demand during instantaneous load transient. The VDDNB controller monitors the current of the VVDDNB_SENSE, and this current is mirrored to internal quick response circuit. At steady state, this mirrored current will not trigger a quick response. When the VVDDNB_SENSE voltage drops abruptly due to load apply transient, the mirrored current flowing into quick response circuit will also increase instantaneously. The QR threshold setting for VDDNB controller refers to Table 5. is a registered trademark of Richtek Technology Corporation. www.richtek.com 37 RT8179B Over Voltage Protection (OVP) QRTHA + CMP - + QR Pulse Generation Circuit VVDDNB_SENSE Figure 21. VDDNB Controller : Quick Response Triggering Circuit When quick response is triggered, the quick response circuit will generate a quick response pulse. The pulse width of quick response is almost the same as tON. After generating a quick response pulse, the pulse is then applied to the on-time generation circuit, and the on-times will be overridden by the quick response pulse. The over voltage protection circuit of the VDDNB controller monitors the output voltage via the VSENA pin after IC POR. When VID is lower than 0.9V, once VVSENA exceeds “0.9V + 325mV”, OVP is triggered and latched. When VID is larger than 0.9V, once VVSENA exceeds the internal reference by 325mV, OVP is triggered and latched. The VDDNB controller will try to turn on low side MOSFETs and turn off high side MOSFETs of the VDDNB controller to protect the CPU. When OVP is triggered by one rail, the other rail will also enter soft shut down sequence. A 1μs delay is used in OVP detection circuit to prevent false trigger. Negative Voltage Protection (NVP) Over Current Protection The RT8179B has dual OCP mechanism. The dual OCP mechanism has two types of thresholds. The first type, referred to as OCP-TDCA, is a time and current based threshold. OCP-TDCA should trip when the output current exceeds TDCA by some percentage and for a period of time. This period of time is referred to as the trigger delay. The second type, referred to as OCP-SPIKEA, is a current based threshold. OCP-SPIKEA should trip when the cycleby-cycle output current exceeds IDDSPIKEA by some percentage. If either mechanism trips, then the VDDNB controller asserts OCP_L and delays any further action. This delay is called an action delay. Refer to action delay time. After the action delay has expired and the VDDNB controller has allowed its current sense filter to settle out and the current has not decreased below the threshold, then the VDDNB controller will turn off both high side MOSFETs and low side MOSFETs of all channels. Users can set OCP-SPIKEA threshold, IL,SUM(SPIKEA), by the current monitor resistor R IMONA of the following equation : RCS IL,SUM(SPIKEA) = 3.19375 0.64 2 DCR RIMONA (38) And set the OCP-TDCA threshold, IL(TDCA), refer to some percentage of OCP-SPIKEA through Table 3. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 38 During OVP latch state, the VDDNB controller also monitors the VSENA pin for negative voltage protection. Since the OVP latch continuously turns on all low side MOSFETs of the VDDNB controller, the VDDNB controller may suffer negative output voltage. As a consequence, when the VVSENA voltage drops below 0V after triggering OVP, the VDDNB controller will trigger NVP to turn off all low side MOSFETs of the VDDNB controller while the high side MOSFETs remains off. After triggering NVP, if the output voltage rises above 0V, the OVP latch will restart to turn on all low side MOSFETs. The NVP function will be active only after OVP is triggered. Under Voltage Protection (UVP) The VDDNB controller implements under voltage protection of VVDDNB. If VVSENA is less than the internal reference by 500mV, the VDDNB controller will trigger UVP latch. The UVP latch will turn off both high side and low side MOSFETs. When UVP is triggered by one rail, the other rail will also enter soft shut down sequence. A 3μs delay is used in UVP detection circuit to prevent false trigger. Under Voltage Lock Out (UVLO) During normal operation, if the voltage at the VCC pin drops below IC POR threshold, the VDDNB controller will trigger UVLO. The UVLO protection forces all high side MOSFETs and low side MOSFETs off by shutting down internal PWM logic drivers. A 3μs delay is used in UVLO detection circuit to prevent false trigger. is a registered trademark of Richtek Technology Corporation. DS8179B-04 January 2015 RT8179B Thermal Considerations PD(MAX) = (TJ(MAX) − TA) / θJA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125°C. The junction to ambient thermal resistance, θJA, is layout dependent. For WQFN-40L 5x5 package, the thermal resistance, θJA, is Maximum Power Dissipation (W)1 For continuous operation, do not exceed absolute maximum junction temperature. The maximum power dissipation depends on the thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : 4.0 Four-Layer PCB 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 22. Derating Curve of Maximum Power Dissipation 27.5°C/W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by the following formula : PD(MAX) = (125°C − 25°C) / (27.5°C/W) = 3.63W for WQFN-40L 5x5 package The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. The derating curve in Figure 22 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS8179B-04 January 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 39 RT8179B Outline Dimension D SEE DETAIL A D2 L 1 E2 E e b 1 1 2 2 DETAIL A Pin #1 ID and Tie Bar Mark Options A A3 A1 Symbol Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.150 0.250 0.006 0.010 D 4.950 5.050 0.195 0.199 D2 3.250 3.500 0.128 0.138 E 4.950 5.050 0.195 0.199 E2 3.250 3.500 0.128 0.138 e L 0.400 0.350 0.016 0.450 0.014 0.018 W-Type 40L QFN 5x5 Package Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. www.richtek.com 40 DS8179B-04 January 2015