MIC4607 85V, Three-Phase MOSFET Driver with Adaptive Dead-Time, Anti-Shoot-Through and Overcurrent Protection General Description Features The MIC4607 is an 85V, three-phase MOSFET driver. The MIC4607 features a fast (35ns) propagation delay time and 20ns driver rise/fall times for a 1nF capacitive load. TTL inputs can be separate high- and low-side signals or a single PWM input with high and low drive generated internally. High- and low-side outputs are guaranteed to not overlap in either mode. The MIC4607 includes overcurrent protection as well as a high-voltage internal diode that charges the high-side gate drive bootstrap capacitor. • Gate drive supply voltage up to 16V • Overcurrent protection • Drives high-side and low-side N-Channel MOSFETs with independent inputs or with a single PWM signal • TTL input thresholds • On-chip bootstrap diodes • Fast 35ns propagation times • Shoot-through protection • Drives 1000pF load with 20ns rise and fall times • Low power consumption • Supply undervoltage protection • –40°C to +125°C junction temperature range A robust, high-speed, and low-power level shifter provides clean level transitions to the high-side output. The robust operation of the MIC4607 ensures that the outputs are not affected by supply glitches, HS ringing below ground, or HS slewing with high-speed voltage transitions. Undervoltage protection is provided on both the low-side and high-side drivers. The MIC4607 is available in a both a 28-pin 4mm × 5mm QFN and 28-pin TSSOP package with an operating junction temperature range of –40°C to +125°C. Applications • Three-phase and BLDC motor drives • Three-phase inverters Datasheets and support documentation are available on Micrel’s website at: www.micrel.com. Typical Application Three-Phase Motor Driver Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com September 15, 2015 Revision 1.1 Micrel, Inc. MIC4607 Ordering Information Part Number Input Version Junction Temperature Range Package MIC4607-1YML TTL Dual Inputs –40°C to +125°C 28-Pin 4mm × 5mm QFN MIC4607-2YML TTL Single PWM Input –40°C to +125°C 28-Pin 4mm × 5mm QFN MIC4607-1YTS TTL Dual Inputs –40°C to +125°C 28-Pin TSSOP MIC4607-2YTS TTL Single PWM Input –40°C to +125°C 28-Pin TSSOP Pin Configurations September 15, 2015 MIC4607-1 28-Pin 4mm × 5mm (ML) (Top View) MIC4607-2 28-Pin 4mm × 5mm (ML) (Top View) MIC4607-1 28-Pin TSSOP (TS) (Top View) MIC4607-2 28-Pin TSSOP (TS) (Top View) 2 Revision 1.1 Micrel, Inc. MIC4607 Pin Description Pin Name Pin Number QFN Pin Number TSSOP “-1” “-2” 1 5 BHI BPWM High-side input (-1) or PWM input (-2) for Phase B. 2 6 ALI NC Low-side input (-1) or no connect (-2) for Phase A. 3 7 AHI APWM High-side input (-1) or PWM input (-2) for Phase A. 4 8 EN Active high enable input. High input enables all outputs and initiates normal operation. Low input shuts down device into a low LQ mode. 5 9 FLT/ Open Drain. FLT/ pin goes low when outputs are latched off due to an overcurrent event. Must be pulled-up to an external voltage with a resistor. 6 10 BHB Phase B High-Side Bootstrap Supply. An external bootstrap capacitor is required. Connect the bootstrap capacitor across this pin and BHS. An onboard bootstrap diode is connected from VDD to BHB. 7 11 BHO Phase B High-Side Drive Output. Connect to the gate of the external high-side power MOSFET. 8 12 BHS Phase B High-Side Driver Return. Connect to the bootstrap capacitor and to a resistor that connect to the source of the external MOSFET. See the Applications section for additional information on the resistor. 9 13 BLO Phase B Low-Side Drive Output. Connect to the gate of the low-side power MOSFET gate. 10 --- NC No Connect. 11 14 ILIM- Differential Current-Limit Input. Connect to most negative end of the external current-sense resistor. 12 15 VSS Power Ground for Phase A and Phase B. 13 16 ILIM+ Differential Current-Limit Input. Connect to most positive end of the external current-sense resistor. 14 17 ALO Phase A Low-Side Drive Output. Connect to the gate of the low-side power MOSFET gate. 15 18 AHS Phase C High-Side Driver Return. Connect to the bootstrap capacitor and to a resistor that connect to the source of the external MOSFET. See the Applications section for additional information on the resistor. 16 19 AHO Phase A High Side Drive Output. Connect to the gate of the external high-side power MOSFET. 17 20 AHB Phase A High-Side Bootstrap Supply. An external bootstrap capacitor is required. Connect the bootstrap capacitor across this pin and AHS. An onboard bootstrap diode is connected from VDD to AHB. 18 21 VDD Input Supply for Gate Drivers and Internal Logic/Control Circuitry. Decouple this pin to VSS with a minimum 2.2µF ceramic capacitor. 19 22 DLY Fault Delay. Connect an external capacitor from this pin to ground to increase the current-limit reset delay. Leave open for minimum delay. Do not externally drive this pin. 20 23 VSS Phase C Power and Control Circuitry Ground. 21 24 CLO Phase C Low-Side Drive Output. Connect to the gate of the low-side power MOSFET gate. September 15, 2015 Pin Function 3 Revision 1.1 Micrel, Inc. MIC4607 Pin Description (Continued) Pin Name Pin Number QFN Pin Number TSSOP 22 25 CHS Phase C High-Side Driver Return. Connect to the bootstrap capacitor and to a resistor that connect to the source of the external MOSFET. See the Applications section for additional information on the resistor. 23 26 CHO Phase C High-Side Drive Output. Connect to the gate of the external high-side power MOSFET. 24 27 CHB Phase C High-Side Bootstrap Supply. An external bootstrap capacitor is required. Connect the bootstrap capacitor across this pin and CHS. An onboard bootstrap diode is connected from VDD to CHB. 25 28 NC No Connect. --- 1 NC No Connect. 26 2 CLI NC Low-Side Input (-1) or No Connect (-2) for Phase C. 27 3 CHI CPWM High-Side Input (-1) or PWM Input (-2) for Phase C. 28 4 BLI NC Low-Side Input (-1) or No Connect (-2) for Phase B. EP September 15, 2015 “-1” “-2” ePad Pin Function Exposed Heatsink Pad: Connect to GND for best thermal performance. 4 Revision 1.1 Micrel, Inc. MIC4607 Absolute Maximum Ratings(1, 2) Operating Ratings(2, 3) Supply Voltage (VDD, VxHB – VxHS) ................... −0.3V to 18V Input Voltages (VxLI, VxHI, VxPWM, VEN) .... −0.3V to VDD + 0.3V FLT/ Pin ................................................ −0.3V to VDD + 0.3V DLY Pin ........................................................... −0.3V to 18V Voltage on xLO (VxLO) .......................... −0.3V to VDD + 0.3V Voltage on xHO (VxHO) .................. VHS − 0.3V to VHB + 0.3V Voltage on xHS (Continuous)............................. −1V to 90V Voltage on xHB ............................................................ 108V ILIM+ ............................................................... –0.3V to +5V ILIM– ............................................................... –0.3V to +2V Average Current in VDD to HB Diode ....................... 100mA Lead Temperature (soldering, 10s) ............................ 260°C Storage Temperature (Ts) ......................... −60°C to +150°C (4) ESD Rating HBM ......................................................................... 1kV MM ......................................................................... 200V CDM ....................................................................... 200V Supply Voltage (VDD) [decreasing VDD] ........... 5.25V to 16V Supply Voltage (VDD) [increasing VDD] .............. 5.5V to 16V Voltage on xHS .................................................. −1V to 85V Voltage on xHS (repetitive transient <100ns) .... −5V to 90V HS Slew Rate ............................................................ 50V/ns Voltage on xHB .............................. VHS + 5.5V to VHS + 16V and/or.......................................... VDD – 1V to VDD + 85V Ambient Temperature (TA) ........................ –40°C to +125°C Junction Temperature (TJ) ........................ –40°C to +125°C Junction Thermal Resistance 4mm × 5mm QFN-28L (θJA) ............................... 43°C/W 4mm × 5mm QFN-28L (θJC).............................. 3.4°C/W TSSOP-28L (θJA) ............................................... 70°C/W TSSOP-28L (θJC) ............................................... 20°C/W Electrical Characteristics(2, 5) VDD = VxHB = 12V; VEN = 5V; VSS = VHS = 0V; No load on xLO or xHO; TA = 25°C; unless noted. Bold values indicate –40°C< TJ < +125°C. Symbol Parameter Condition (2) Min. Typ. Max. Units µA Supply Current IDD VDD Quiescent Current xLI = xHI = 0V 390 750 IDDSH VDD Shutdown Current xLI = xHI = 0V; EN = 0V with HS = floating 2.2 10 µA xLI = xHI = 0V ; EN = 0V; HS = 0V 58 150 IDDO VDD Operating Current f = 20kHz 0.6 1.5 mA IHB Per Channel xHB Quiescent Current xLI = xHI = 0V or xLI = 0V and xHI = 5V 20 75 µA IHBO Per Channel xHB Operating Current f = 20kHz 30 400 µA IHBS xHB to VSS Current, Quiescent VxHS = VxHB = 90V 0.05 5 µA 30 300 µA IHBSO xHB to VSS Current, Operating f = 20kHz Notes: 1. Exceeding the absolute maximum ratings may damage the device. 2. “x” in front of a pin name refers to either A, B or C phase. (e.g. xHI can be either AHI, BHI or CHI). 3. The device is not guaranteed to function outside its operating ratings. 4. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF. 5. Specification for packaged product only. September 15, 2015 5 Revision 1.1 Micrel, Inc. MIC4607 Electrical Characteristics(2, 5) (Continued) VDD = VxHB = 12V; VEN = 5V; VSS = VHS = 0V; No load on xLO or xHO; TA = 25°C; unless noted. Bold values indicate –40°C< TJ < +125°C. Symbol Parameter Input (TTL: xLI, xHI, xPWM, EN) Condition (2) Min. Typ. Max. Units 0.8 V (6) VIL Low-Level Input Voltage VIH High-Level Input Voltage VHYS Input Voltage Hysteresis RI Input Pull-Down Resistance 2.2 V 0.1 V xLI and xHI Inputs (-1 Version) 100 300 500 xPWM Input (-2 Version) 50 130 250 3.8 4.4 4.9 kΩ Undervoltage Protection VDDR VDD Falling Threshold VDDH VDD Threshold Hysteresis VHBR xHB Falling Threshold VHBH xHB Threshold Hysteresis 0.25 4.0 4.4 V V 4.9 0.25 V V Overcurrent Protection VILIM+ Rising Overcurrent Threshold (VILIM+ – VILIM–) 175 200 tILIM_PROP ILIM to Gate Propagation Delay VILIM+ = 0.5V peak 70 VOLF FLT/ Output Low Voltage VILIM = 1V; IFLT/ = 1mA 0.2 VDLY+ Rising DLY Threshold IDLY DLY Current Source VDLY = 0V tFCL Fault Clear Time CDLY = 1nF 670 225 mV ns Fault Circuit 0.5 1.5 0.3 0.44 V V 0.6 µA µs Bootstrap Diode VDL Low-Current Forward Voltage IVDD-xHB = 100µA 0.4 0.70 V VDH High-Current Forward Voltage IVDD-xHB = 50mA 0.8 1 V RD Dynamic Resistance IVDD-xHB = 50mA 4 6 Ω xLO Gate Driver VOLL Low-Level Output Voltage IxLO = 50mA 0.3 0.6 V VOHL High-Level Output Voltage IxLO = −50mA, VOHL = VDD - VxLO 0.5 1 V IOHL Peak Sink Current VxLO = 0V 1 A IOLL Peak Source Current VxLO = 12V 1 A Note: 6. VIL(MAX) = maximum positive voltage applied to the input which will be accepted by the device as a logic low. VIH(MIN) = minimum positive voltage applied to the input which will be accepted by the device as a logic high. September 15, 2015 6 Revision 1.1 Micrel, Inc. MIC4607 Electrical Characteristics(2, 5) (Continued) VDD = VxHB = 12V; VEN = 5V; VSS = VHS = 0V; No load on xLO or xHO; TA = 25°C; unless noted. Bold values indicate –40°C< TJ < +125°C. Symbol Parameter Condition (2) Min. Typ. Max. Units xHO Gate Driver VOLH Low-Level Output Voltage IxHO = 50mA 0.3 0.6 V VOHH High-Level Output Voltage IxHO = −50mA, VOHH = VxHB – VxHO 0.5 1 V IOHH Peak Sink Current VxHO = 0V 1 A IOLH Peak Source Current VxHO = 12V 1 A Switching Specifications (LI/HI mode with inputs non-overlapping, assumes HS low before LI goes high and LO low before HI goes high). tLPHL Lower Turn-Off Propagation Delay (LI Falling to LO Falling) 35 75 ns tHPHL Upper Turn-Off Propagation Delay (HI Falling to HO Falling) 35 75 ns tLPLH Lower Turn-On Propagation Delay (LI Rising to LO Rising) 35 75 ns tHPLH Upper Turn-On Propagation Delay (HI Rising to HO Rising) 35 75 ns tR/F Output Rise/Fall Time CL = 1000pF 20 ns tR/F Output Rise/Fall Time (3V to 9V) CL = 0.1µF 0.8 µs tPW Minimum Input Pulse Width that Changes the Output Note 7 50 ns Switching Specifications PWM Mode (MIC4607-2) or LI/HI mode (MIC4607-1) with Overlapping LI/HI Inputs tLOOFF Delay from PWM Going High / LI Low, to LO Going Low 35 VLOOFF LO Output Voltage Threshold for LO FET to be Considered Off 1.9 tHOON Delay from LO Off to HO Going High 35 75 ns tHOOFF Delay from PWM or HI Going Low to HO Going Low 35 75 ns VSWTH Switch Node Voltage Threshold Signaling HO is Off 2.2 4 V tLOON Delay between HO FET Being Considered Off to LO Turning On 35 75 ns tSWTO Forced xLO On if VSWTH is Not Detected 250 500 ns 1 100 75 ns V Note: 7. Guaranteed by design. Not production tested. September 15, 2015 7 Revision 1.1 Micrel, Inc. MIC4607 Timing Diagrams Non-Overlapping LI/HI Input Mode (MIC4607-1) In non-overlapping LI/HI input mode, enough delay is added between the xLI and xHI inputs to allow xHS to be low before xLI is pulled high and similarly xLO is low before xHI goes high. Likewise, xLI going high forces xLO high after typical delay of 35ns (tLPLH) and xLO follows low transition of xLI after typical delay of 35ns (tLPHL). xHO goes high with a high signal on xHI after a typical delay of 35ns (tHPLH). xHI going low drives xHO low also with typical delay of 35ns (tHPHL). . xHO and xLO output rise and fall times (tR/tF) are typically 20ns driving 1000pF capacitive loads xHS 0V tF tR xHO tHPLH tR tHPHL tF xLO tLPLH tLPHL xHI xLI Figure 1. Separate Non-Overlapping LI/HI Input Mode (MIC4607-1) Notes: All propagation delays are measured from the 50% voltage level and rise/fall times are measured 10% to 90%. “x” in front of a pin name refers to either A, B or C phase. (e.g. xHI can be either AHI, BHI or CHI). September 15, 2015 8 Revision 1.1 Micrel, Inc. MIC4607 Timing Diagrams (Continued) Overlapping LI/HI Input Mode (MIC4607-1) When xLI/xHI input high signals overlap, xLO/xHO output states are determined by the first output to be turned on. That is, if xLI goes high (ON), while xHO is high, xHO stays high until xHI goes low at which point, after a delay of tHOOFF and when xHS < 2.2V, xLO goes high with a delay of tLOON. Should xHS never trip the aforementioned internal comparator reference (2.2V), a falling xHI edge delayed by a typical 250ns will set “HS latch” allowing xLO to go high. If xHS falls very fast, xLO will be held low by a 35ns delay gated by HI going low. Conversely, xHI going high (ON) when xLO is high has no effect on outputs until xLI is pulled low (off) and xLO falls to < 1.9V. Delay from xLI going low to xLO falling is tLOOFF and delay from xLO < 1.9V to xHO being on is tHOON. 2.2V (typ) xHS 0V tLOON xHO tHOON tHOOFF 1.9V (typ) xLO tLOOFF xHI xLI Figure 2. Separate Overlapping LI/HI Input Mode (MIC4607-1) September 15, 2015 9 Revision 1.1 Micrel, Inc. MIC4607 Timing Diagrams (Continued) PWM Input Mode (MIC4607-2) A low going xPWM signal applied to the MIC4607-2 causes xHO to go low, typically 35ns (tHOOFF) after the xPWM input goes low, at which point the switch node, xHS, falls (1 − 2). A 35ns delay gated by xPWM going low can determine the time to xLO going high for fast falling HS designs. xPWM going high forces xLO low in typically 35ns (tLOOFF) (5 − 6). When xLO reaches 1.9V (VLOOFF), the low-side MOSFET is deemed off and xHO is allowed to go high. The delay between these two points is typically 35ns (tHOON) (7 − 8). When xHS reaches 2.2V (VSWTH), the external high-side MOSFET is deemed off and xLO goes high, typically within 35ns (tLOON) (3-4). xHS falling below 2.2V sets a latch that can only be reset by xPWM going high. This design prevents ringing on xHS from causing an indeterminate xLO state. Should xHS never trip the aforementioned internal comparator reference (2.2V), a falling xPWM edge delayed by 250ns will set “HS latch” allowing xLO to go high. xHO and xLO output rise and fall times (tR/tF) are typically 20ns driving 1000pF capacitive loads. tR tF 2 xHO tHOON tR 4 6 xLO 7 (VLOOFF) tF tLOOFF tLOON 3 (VSWTH) xHS 0V 1 5 xPWM tHOOFF Figure 3. PWM Mode (MIC4607-2) September 15, 2015 10 Revision 1.1 Micrel, Inc. MIC4607 Overcurrent Timing Diagram The motor current is sensed in an external resistor that is connected between the low-side MOSFET’s source pins and ground. If the sense resistor voltage exceeds the rising overcurrent threshold (typically 0.2V), all LO and HO outputs are latched off and the FLT/ pin is pulled low. Once the outputs are latched off, an internal current source (typically 0.44uA) begins to charge up the external CDELAY capacitor. The outputs remain latched off and all xLI/xHI (or xPWM) input signals are ignored until the voltage on the CDELAY capacitor rises above the VDLY+ threshold (typically 1.5V), which resets the latch on the first rising edge of any LI input of the MIC4607-1 (or falling edge on any PWM input for the MIC4607-2). Once this occurs, the CDLY capacitor is discharged, the FLT/ pin returns to a high impedance state and all outputs will respond to their respective input signals. On startup, the current limit latch is reset during a rising VDD or a rising EN pin voltage to assure normal operation. Figure 4. Overcurrent Timing Diagram September 15, 2015 11 Revision 1.1 Micrel, Inc. MIC4607 Typical Characteristics VDD Quiescent Current vs. VDD Voltage VDD Quiescent Current vs. Temperature VHB Quiescent Current (All Channels) vs. VHB Voltage 125°C VEN = 5V 460 430 400 25°C 370 340 310 -40°C 280 100 480 VEN = 5V 460 440 420 400 380 360 340 320 VDD = 5.5V 300 VDD = 12V 8 9 10 11 12 13 14 15 16 -25 IVDD+VHB SHUTDOWN CURRENT (µA) VxHS = GND VEN = 5V VHB = 16V 80 70 60 VHB = 12V VHB = 5.5V 40 30 20 -50 -25 0 25 50 0 75 100 125 7 xHI = xLI = 0V VxHS = FLOATING VEN = 0V 6 VDD = VHB 4 VDD = VHB -40°C 90 80 25°C 70 60 50 40 125°C 30 20 5 6 7 8 9 10 11 12 13 14 15 16 VDD+HB (V) September 15, 2015 100 60 50 40 25°C 30 125°C 125 5 6 7 8 10 11 12 13 14 15 16 9 VHB (V) -40°C 125°C 3 2 1 25°C VDD+HB Shutdown Current (Floating Switch Node) vs. Temperature 8 xHI = xLI = 0V VxHS = FLOATING VEN = 0V 7 VDD= 16V VDD = VHB 6 5 VDD= 12V 4 3 VDD = 5.5V 2 1 0 0 5 6 7 8 9 -50 10 11 12 13 14 15 16 -25 0 xHI = xLI = 0V VxHS = GND VDD= 16V 100 VEN = 0V VDD = VHB 90 80 70 60 VDD = 5.5V 50 40 VDD= 12V 30 20 -50 -25 0 25 50 75 TEMPERATURE (°C) 12 50 75 100 125 VDD+HB Operating Current vs. Switching Frequency 120 110 25 TEMPERATURE (°C) VDD+HB Shutdown Current (Grounded Switch Node) vs. Temperature IVDD+VHB SHUTDOWN CURRENT (µA) VEN = 0V -40°C 70 VDD+HB (V) 120 100 75 5 VDD+HB Shutdown Current (Grounded Switch Node) vs. Voltage 110 50 8 TEMPERATURE (°C) xHI = xL I= 0V VxHS = GND 25 VDD+HB Shutdown Current (Floating Switch Node) vs. Voltage 100 50 VEN = 5V 80 TEMPERATURE (°C) VHB Quiescent Current (All Channels) vs. Temperature 90 VxHS = GND 90 20 -50 IVDD+VHB SHUTDOWN CURRENT (uA) 7 IDD+VHB OPERATING CURRENT (mA) 6 VDD (V) IVHB QUIESCENT CURRENT (µA) VxHS = GND VDD = 16V 280 5 IVDD+VHB SHUTDOWN CURRENT (µA) IVHB QUIESCENT CURRENT (µA) VxHS = GND IVDD QUIESCENT CURRENT (µA) IVDD QUIESCENT CURRENT (µA) 500 490 100 125 1.5 VDD = 12V VxHS = 0V CLOAD = 0nF 1.4 1.3 1.2 1.1 1 25ºC 0.9 –40ºC 0.8 0.7 0.6 125ºC 0.5 0.4 0.3 0.2 0 10 20 30 40 50 60 70 80 90 100 FREQUENCY (kHz) Revision 1.1 Micrel, Inc. MIC4607 Typical Characteristics (Continued) HO/LO Sink On-Resistance vs. VDD 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 20 25ºC 25ºC –40ºC VEN = VHB = VDD VEN = VHB = VDD 15 RON SINK (Ω) 125ºC VxHS = GND VxHS = GND 125ºC 10 10 –40ºC VDD = 16V 0 0 20 30 40 50 60 70 80 90 100 5 6 7 8 12 13 14 15 -50 16 RON SOURCE (Ω) 15 10 50 75 100 125 70 VEN = VHB = VDD 20 TAMB = 25°C VxHS = 0V CL= 1nF tHPLH 60 VDD = 5.5V VDD = 12V 15 tHPHL 50 tLPLH 40 tLPHL 10 30 –40ºC VDD = 16V 20 5 5 7 8 9 10 11 12 13 14 15 -50 16 -25 0 25 50 75 100 5 125 6 7 8 9 TEMPERATURE (°C) VDD (V) 70 11 12 13 14 15 16 Output Fall Time vs. VDD Voltage 45 50 VDD = 12V VxHS = 0V CL=1nF 10 VDD (V) Output Rise Time vs. VDD Voltage Propagation Delay (HI/LI Input) vs. Temperature 60 25 Propagation Delay (HI/LI Input) vs. VDD Voltage VxHS = GND 25ºC 6 0 IHO/LO = −50mA VEN = VHB = VDD 5 -25 TEMPERATURE (°C) 25 VxHS = GND 20 11 HO/LO Source On-Resistance vs. Temperature IHO/LO = −50mA 125ºC 10 VDD (V) HO/LO Source On-Resistance vs. VDD 25 9 DELAY (ns) 10 VDD = 12V VDD = 5.5V 5 5 FREQUENCY (kHz) RON SOURCE (Ω) IHO/LO = 50mA IHO/LO = 50mA 15 0 VxHS = 0V CL = 1nF 45 VxHS = 0V CL = 1nF 40 40 35 35 30 tLPLH tLPHL tf (ns) 25°C 50 tr (ns) DELAY (ns) HO/LO Sink On-Resistance vs. Temperature 20 VDD = 16V VxHS = 0V CLOAD=0nF RON SINK (Ω) IDD+VHB OPERATING CURRENT (mA) VDD+HB Operating Current vs. Switching Frequency 30 125°C 25 125°C 40 25 20 25°C 15 20 30 tHPHL tHPLH 15 20 -50 -25 0 25 50 75 TEMPERATURE (°C) September 15, 2015 100 125 –40°C 10 –40°C 5 10 5 6 7 8 9 10 11 VDD (V) 13 12 13 14 15 16 5 6 7 8 9 10 11 12 13 14 15 16 VDD (V) Revision 1.1 Micrel, Inc. MIC4607 Typical Characteristics (Continued) Rise/Fall Time vs. Temperature Dead Time vs. VDD Voltage 130 55 RISE TIME VDD = 5.5V 45 110 FALL TIME VDD = 5.5V 35 30 25 20 15 FALL TIME RISE TIME VDD = 12V VDD = 12V 10 5 -50 -25 0 125°C 100 DEAD TIME (ns) 40 130 25 50 75 VxHS = 0V CL=1nF TAMB = 25°C 120 100 110 25°C 90 –40°C 80 70 60 50 90 80 VDD = 16V 70 VDD = 12V 60 50 40 30 30 20 VDD = 5.5V 100 40 20 10 10 5 125 VDD= 12V VxHS = 0V CL=1nF 120 DEAD TIME (ns) VxHS = 0V CL=1nF 50 tr/tf (ns) Dead Time vs. Temperature 6 7 8 TEMPERATURE (°C) 9 10 11 12 13 14 15 16 VDD (V) -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) VDD/VHB UVLO vs. Temperature 4.9 VHB RISING UVLO THRESHOLD (V) 4.8 VxHS = 0V 4.7 4.6 VHB FALLING 4.5 4.4 4.3 VDD RISING 4.2 4.1 VDD FALLING 4 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) Overcurrent Propagation Delay vs. VDD Voltage Overcurrent Propagation Delay vs. Temperature 120 120 VxHS = 0V 100 90 25°C –40°C 80 70 60 50 PROPAGATION DELAY (ns) PROPAGATION DELAY (ns) VHS = 0V 125°C 110 VDD = 16V 110 VDD = 5.5V 100 90 80 70 VDD = 12V 60 50 5 6 7 8 9 10 11 VDD (V) September 15, 2015 12 13 14 15 16 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 14 Revision 1.1 Micrel, Inc. MIC4607 Typical Characteristics (Continued) September 15, 2015 15 Revision 1.1 Micrel, Inc. MIC4607 Functional Diagram Figure 5. MIC4607 xPhase Top-Level Functional Diagram Figure 6. Input Logic Block September 15, 2015 16 Revision 1.1 Micrel, Inc. MIC4607 Functional Description A high level applied to the xLI pin causes VDD to be applied to the gate of the external MOSFET. A low level on the xLI pin grounds the gate of the external MOSFET. The MIC4607 is a non-inverting, 85V three-phase MOSFET driver designed to independently drive all six NChannel MOSFETs in a three-phase bridge. The MIC4607 offers a wide 5.5V to 16V VDD operating supply range with either six independent TTL inputs (MIC46071) or three PWM inputs, one for each phase (MIC46072). Refer to the Functional Diagram section. The drivers contain input buffers with hysteresis, four independent UVLO circuits (three high-side and one lowside), and six output drivers. The high-side output drivers utilize a high-speed level-shifting circuit that is referenced to its HS pin. Each phase has an internal diode that is used by the bootstrap circuits to provide the drive voltages for each of the three high-side outputs. A programmable overcurrent protection circuit turns off all outputs during an overcurrent fault. Startup and UVLO The UVLO circuits force the driver’s outputs low until the supply voltage exceeds the UVLO threshold. The lowside UVLO circuit monitors the voltage between the VDD and VSS pins. The high-side UVLO circuits monitor the voltage between the xHB and xHS pins. Hysteresis in the UVLO circuits prevent system noise and finite circuit impedance from causing chatter during turn-on. Figure 7. Low-Side Driver Block Diagram High-Side Driver and Bootstrap Circuit Figure 8 illustrates a block diagram of the high-side driver and bootstrap circuit. This driver is designed to drive a floating N-channel MOSFET, whose source terminal is referenced to the HS pin. Enable Inputs There is one external enable pin that controls all three phases. A logic high on the enable pin (EN) allows for startup of all phases and normal operation. Conversely, when a logic low is applied on the enable pin, all phases turn-off and the device enters a low current shutdown mode. All outputs (xHO and xLO) are pulled low when EN is low. Do not leave the EN pin floating. Input Stage All input pins (xLI and xHI) are referenced to the VSS pin. The MIC4607 has a TTL-compatible input range and can be used with input signals with amplitude less than the supply voltage. The threshold level is independent of the VDD supply voltage and there is no dependence between IVDD and the input signal amplitude. This feature makes the MIC4607 an excellent level translator that will drive high level gate threshold MOSFETs from a low-voltage PWM IC. Low-Side Driver The low-side driver is designed to drive a ground (VSS pin) referenced N-channel MOSFET. Low driver impedances allow the external MOSFET to be turned on and off quickly. The rail-to-rail drive capability of the output ensures a low RDSON from the external power device. Refer to Figure 7. September 15, 2015 Figure 8. High-Side Driver and Bootstrap-Circuit Block Diagram 17 Revision 1.1 Micrel, Inc. MIC4607 In low-current applications, the losses due to RDSON are minimal, but in high-current motor drive applications such as power tools, the difference in RDSON can lower the efficiency, reducing run time. A low-power, high-speed, level-shifting circuit isolates the low side (VSS pin) referenced circuitry from the high-side (xHS pin) referenced driver. Power to the high-side driver and UVLO circuit is supplied by the bootstrap capacitor (CB) while the voltage level of the xHS pin is shifted high. The bootstrap circuit consists of an internal diode and external capacitor, CB. In a typical application, such as the motor driver shown in Figure 9 (only Phase A illustrated), the AHS pin is at ground potential while the low-side MOSFET is on. The internal diode charges capacitor CB to VDD-VF during this time (where VF is the forward voltage drop of the internal diode). After the lowside MOSFET is turned off and the AHO pin turns on, the voltage across capacitor CB is applied to the gate of the high-side external MOSFET. As the high-side MOSFET turns on, voltage on the AHS pin rises with the source of the high-side MOSFET until it reaches VIN. As the AHS and AHB pins rise, the internal diode is reverse biased, preventing capacitor CB from discharging. During this time, the high-side MOSFET is kept ON by the voltage across capacitor CB. Figure 10. MOSFET RDSON vs. VGS Overcurrent Protection Circuitry The MIC4607 provides overcurrent protection for the motor driver circuitry. It consists of: • A comparator that senses the voltage across a currentsense resistor • A latch and timer that keep all gate drivers off during a fault • An open-drain pin that pulls low during the fault. If an overcurrent condition is detected, the FLT/ pin is pulled low and the gate drive outputs are latched off for a time that is determined by the DLY pin circuitry. After the delay circuitry times out, a high-going edge on any of the LI pins (for the MIC4607-1 version) or a low-going edge on any of the PWM pins (for the MIC4607-2 version) is required to reset the latch, de-assert the FLT/ pin and allow the gate drive outputs to switch. Figure 9. MIC4607 Motor Driver Example Programmable Gate Drive The MIC4607 offers programmable gate drive, meaning the MOSFET gate drive (gate-to-source voltage) equals the VDD voltage. This feature offers designers flexibility in selecting the proper MOSFETs for a given application. Different MOSFETs require different VGS characteristics for optimum RDSON performance. Typically, the higher the gate voltage (up to 16V), the lower the RDSON achieved. For example, as shown in Figure 10, a NTMSF4899NF MOSFET can be driven to the ON state with a gate voltage of 5.5V but RDSON is 5.2mΩ. If driven to 10V, RDSON is 4.1mΩ – a decrease of 20%. September 15, 2015 For additional information, refer to the Timing Diagrams section as well as the Functional Diagram section. ILIM The ILIM+ and ILIM- pins provide a Kelvin-sensed circuit that monitors the voltage across an external current sense resistor. This resistor is typically connected between the source pins of all three low-side MOSFETs and power ground. If the peak voltage across this resistor exceeds the VILIM+ threshold, it will cause all six outputs to latch off. Both pins should be shorted to VSS ground if the overcurrent features is not used. 18 Revision 1.1 Micrel, Inc. MIC4607 DLY A capacitor connected to the DLY pin determines the amount of time the gate drive outputs are latched off before they can be restarted. During normal operation, the DLY pin is held low by an internal MOSFET. After an over-current condition is detected, the MOSFET turns off and the external capacitor is charged up by an internal current source. The outputs remain latched off until the DLY pin voltage reaches the VDLY+ threshold (typically 1.5V). The delay time can be approximately calculated using Equation 1: t DLY = CDLY × VDLY − IDLY Eq. 1 Where: CDLY is the external capacitance on the DLY pin IDLY is the DLY pin current source (typically 0.44µA) VDLY+ is the internal comparator threshold (typically 1.5V) FLT/ This open-drain output is pulled low while the gate drive outputs are latched off after an over-current condition. It will de-assert once the DLY pin has reached the VDLY+ threshold and a rising edge occurs on any LI pin (for the MIC4607-1) or a falling edge on any PWM pin (MIC46072). During normal operation, the internal pull-down MOSFET is of the pin is high impedance. A pull-up resistor must be connected to this pin. September 15, 2015 19 Revision 1.1 Micrel, Inc. MIC4607 Application Information Adaptive Dead Time For each phase, it is important that both MOSFETs of the same phase branch are not conducting at the same time or VIN will be shorted to ground and current will “shoot through” the MOSFETs. Excessive shoot-through causes higher power dissipation in the MOSFETs, voltage spikes and ringing. The high switching current and voltage ringing generate conducted and radiated EMI. The internal gate resistance (RG_FET) and any external damping resistor (RG) and HS pin resistor (RHS), isolate the MOSFET’s gate from the driver output. There is a delay between when the driver output goes low and the MOSFET turns off. This turn-off delay is usually specified in the MOSFET data sheet. This delay increases when an external damping resistor is used. Minimizing shoot-through can be done passively, actively or through a combination of both. Passive shoot-through protection can be achieved by implementing delays between the high and low gate drivers to prevent both MOSFETs from being on at the same time. These delays can be adjusted for different applications. Although simple, the disadvantage of this approach is that it requires long delays to account for process and temperature variations in the MOSFET and MOSFET driver. The MIC4607 uses a combination of active sensing and passive delay to ensure that both MOSFETs are not on at the same time. Figure 12 illustrates how the adaptive dead-time circuitry works. Adaptive Dead Time monitors voltages on the gate drive outputs and switch node to determine when to switch the MOSFETs on and off. This active approach adjusts the delays to account for some of the variations, but it too has its disadvantages. High currents and fast switching voltages in the gate drive and return paths can cause parasitic ringing to turn the MOSFETs back on even while the gate driver output is low. Another disadvantage is that the driver cannot monitor the gate voltage inside the MOSFET. Figure 11 shows an equivalent circuit of the high-side gate drive. Figure 12. Adaptive Dead-Time Logic Diagram For the MIC4607-2, a high level on the xPWM pin causes HI to go low and LI to go high. This causes the xLO pin to go low. The MIC4607 monitors the xLO pin voltage and prevents the xHO pin from turning on until the voltage on the xLO pin reaches the VLOOFF threshold. After a short delay, the MIC4607 drives the xHO pin high. Monitoring the xLO voltage eliminates any excessive delay due to the MOSFET driver’s turn-off time and the short delay accounts for the MOSFET turn-off delay as well as letting the xLO pin voltage settle out. If an external resistor is used between the xLO output and the MOSFET gate, it must be made small enough to prevent excessive voltage drop across the resistor during turn-off. Figure 13 illustrates using a diode (DLS) and resistor (RLS2) in parallel with the gate resistor to prevent a large voltage drop between the xLO pin and MOSFET gate voltages during turn-off. Figure 11. MIC4607 Driving an External MOSFET September 15, 2015 20 Revision 1.1 Micrel, Inc. MIC4607 The maximum duty cycle (ratio of high-side on-time to switching period) is determined by the time required for the CB capacitor to charge during the off-time. Adequate time must be allowed for the CB capacitor to charge up before the high-side driver is turned back on. Although the adaptive dead-time circuit in the MIC4607 prevents the driver from turning both MOSFETs on at the same time, other factors outside of the anti-shoot-through circuit’s control can cause shoot-through. Other factors include ringing on the gate drive node and capacitive coupling of the switching node voltage on the gate of the low-side MOSFET. The scope photo in Figure 14 shows the dead time (<20ns) between the high- and low-side MOSFET transitions as the low-side driver switches off while the high-side driver transitions from off to on. Figure 13. Low-Side Drive Gate Resistor Configuration A low on the xPWM pin causes HI to go high and LI to go low. This causes the xHO pin to go low after a short delay (tHOOFF). Before the xLO pin can go high, the voltage on the switching node (xHS pin) must have dropped to 2.2V. Monitoring the switch voltage instead of the xHO pin voltage eliminates timing variations and excessive delays due to the high side MOSFET turn-off. The xLO driver turns on after a short delay (tLOON). Once the xLO driver is turned on, it is latched on until the xPWM signal goes high. This prevents any ringing or oscillations on the switch node or xHS pin from turning off the xLO driver. If the xPWM pin goes low and the voltage on the xHS pin does not cross the VSWTH threshold, the xLO pin will be forced high after a short delay (tSWTO), insuring proper operation. Figure 14. Adaptive Dead-Time LO (LOW) to HO (HIGH) Table 1 contains truth tables for the MIC4607-1 (independent TTL inputs) and Table 2 is for the MIC46072 (PWM inputs) that details the “first on” priority as well as the failsafe delay (tSWTO). The internal logic circuits also insure a “first on” priority at the inputs. If the xHO output is high, the xLI pin is inhibited. A high signal or noise glitch on the xLI pin has no effect on the xHO or xLO outputs until the xHI pin goes low. Similarly, xLO being high holds xHO low until xLI and xLO are low. Table 1. MIC4607-1 Truth Table Fast propagation delay between the input and output drive waveform is desirable. It improves overcurrent protection by decreasing the response time between the control signal and the MOSFET gate drive. Minimizing propagation delay also minimizes phase shift errors in power supplies with wide bandwidth control loops. Care must be taken to ensure that the input signal pulse width is greater than the minimum specified pulse width. An input signal that is less than the minimum pulse width can result in no output pulse or an output pulse whose width is significantly less than the input. September 15, 2015 21 xLI xHI xLO xHO Comments 0 0 0 0 Both outputs off. 0 1 0 1 xHO will not go HIGH until xLO falls below 1.9V. 1 0 1 0 xLO will be delayed an extra 250ns if xHS never falls below 2.2V. 1 1 X X First ON stays on until input of same goes LOW. Revision 1.1 Micrel, Inc. MIC4607 Table 2. MIC4607-2 Truth Table xPWM xLO xHO 0 1 0 1 0 1 DBST VIN Comments CB VDD xLO will be delayed an extra 250ns if xHS never falls below 2.2V. AHB CVDD AHI Level shift xHO will not go HIGH until xLO falls below 1.9V. AHO RG AHS RHS 3Ω DCLAMP Phase A ALI HS Node Clamp A resistor/diode clamp between the switching node and the HS pin is necessary to clamp large negative glitches or pulses on the HS pin. ALO R G MIC4607 VSS Figure 15 shows the Phase A section high-side and lowside MOSFETs connected to one phase of the three phase motor. There is a brief period of time (dead time) between switching to prevent both MOSFETs from being on at the same time. When the high-side MOSFET is conducting during the on-time state, current flows into the motor. After the high-side MOSFET turns off, but before the low-side MOSFET turns on, current from the motor flows through the body diode in parallel with the low-side MOSFET. Depending upon the turn-on time of the body diode, the motor current, and circuit parasitics, the initial negative voltage on the switch node can be several volts or more. The forward voltage drop of the body diode can be several volts, depending on the body diode characteristics and motor current. M Phases B&C Figure 15. Negative HS Pin Voltage Power Dissipation Considerations Power dissipation in the driver can be separated into three areas: • Internal diode dissipation in the bootstrap circuit • Internal driver dissipation • Quiescent current dissipation used to supply the internal logic and control functions. Bootstrap Circuit Power Dissipation Power dissipation of the internal bootstrap diode primarily comes from the average charging current of the bootstrap capacitor (CB) multiplied by the forward voltage drop of the diode. Secondary sources of diode power dissipation are the reverse leakage current and reverse recovery effects of the diode. Even though the HS pin is rated for negative voltage, it is good practice to clamp the negative voltage on the HS pin with a resistor and possibly a diode to prevent excessive negative voltage from damaging the driver. Depending upon the application and amount of negative voltage on the switch node, a 3Ω resistor is recommended. If the HS pin voltage exceeds 0.7V, a diode between the xHS pin and ground is recommended. The diode reverse voltage rating must be greater than the high-voltage input supply (VIN). Larger values of resistance can be used if necessary. The average current drawn by repeated charging of the high-side MOSFET is calculated by: IF( AVE) = QGATE × fS Adding a series resistor in the switch node limits the peak high-side driver current during turn-off, which affects the switching speed of the high-side driver. The resistor in series with the HO pin may be reduced to help compensate for the extra HS pin resistance. September 15, 2015 VNEG Eq. 1 Where: QGATE = Total gate charge at VHB – VHS. fS = Gate drive switching frequency. 22 Revision 1.1 Micrel, Inc. MIC4607 The average power dissipated by the forward voltage drop of the diode equals: PDIODE FWD = IF( AVE ) × VF Eq. 2 Where: VF = Diode forward voltage drop. There are three phases in the MIC4607. The power dissipation for each of the bootstrap diodes must be calculated and summed to obtain the total bootstrap diode power dissipation for the package. The value of VF should be taken at the peak current through the diode; however, this current is difficult to calculate because of differences in source impedances. The peak current can either be measured or the value of VF at the average current can be used, which will yield a good approximation of diode power dissipation. The reverse leakage current of the internal bootstrap diode is typically 3µA at a reverse voltage of 85V at 125°C. Power dissipation due to reverse leakage is typically much less than 1mW and can be ignored. Figure 16. Optional External Bootstrap Diode Gate Driver Power Dissipation Power dissipation in the output driver stage is mainly caused by charging and discharging the gate to source and gate to drain capacitance of the external MOSFET. Figure 17 shows a simplified equivalent circuit of the MIC4607 driving an external high-side MOSFET. An optional external bootstrap diode may be used instead of the internal diode (Figure 16). An external diode may be useful if high gate charge MOSFETs are being driven and the power dissipation of the internal diode is contributing to excessive die temperatures. The voltage drop of the external diode must be less than the internal diode for this option to work. The reverse voltage across the diode will be equal to the input voltage minus the VDD supply voltage. The above equations can be used to calculate power dissipation in the external diode; however, if the external diode has significant reverse leakage current, the power dissipated in that diode due to reverse leakage can be calculated as: PDIODEREV = IR × VREV × (1 − D) Eq. 3 Where: IR = Reverse current flow at VREV and TJ. VREV = Diode reverse voltage. D = Duty cycle = tON × fS. Figure 17. MIC4607 Driving an External High-Side MOSFET The on-time is the time the high-side switch is conducting. In most topologies, the diode is reverse biased during the switching cycle off-time. September 15, 2015 23 Revision 1.1 Micrel, Inc. MIC4607 The same energy is dissipated by ROFF, RG, and RG_FET when the driver IC turns the MOSFET off. Assuming RON is approximately equal to ROFF, the total energy and power dissipated by the resistive drive elements is: Dissipation during the External MOSFET Turn-On Energy from capacitor CB is used to charge up the input capacitance of the MOSFET (CGD and CGS). The energy delivered to the MOSFET is dissipated in the three resistive components, RON, RG and RG_FET. RON is the on resistance of the upper driver MOSFET in the MIC4607. RG is the series resistor (if any) between the driver and the MOSFET. RG_FET is the gate resistance of the MOSFET and is typically listed in the power MOSFET’s specifications. The ESR of capacitor CB and the resistance of the connecting etch can be ignored since they are much less than RON and RG_FET. EDRIVER = QG × VGS and PDRIVER = QG × VGS × fS Supply Current Power Dissipation Power is dissipated in the input and control sections of the MIC4607, even if there is no external load. Current is still drawn from the VDD and HB pins for the internal circuitry, the level shifting circuitry, and shoot-through current in the output drivers. The VDD and VHB currents are proportional to operating frequency and the VDD and VHB voltages. The typical characteristic graphs show how supply current varies with switching frequency and supply voltage. The effective capacitances of CGD and CGS are difficult to calculate because they vary non-linearly with ID, VGS, and VDS. Fortunately, most power MOSFET specifications include a typical graph of total gate charge versus VGS. Figure 18 shows a typical gate charge curve for an arbitrary power MOSFET. This chart shows that for a gate voltage of 10V, the MOSFET requires about 23.5nC of charge. The energy dissipated by the resistive components of the gate drive circuit during turn-on is calculated as: E= The power dissipated by the MIC4607 due to supply current is: 1 × CISS × VGS 2 2 PDISS SUPPLY = VDD × IDD + VHB × IHB but Q = C× V so, E= Eq. 5 Eq. 6 Eq. 4 Values for IDD and IHB are found in the EC table and the typical characteristics graphs. 1 × QG × VGS 2 Total Power Dissipation and Thermal Considerations Total power dissipation in the MIC4607 is equal to the power dissipation caused by driving the external MOSFETs, the supply currents and the internal bootstrap diodes. Where: CISS = Total gate capacitance of the MOSFET. PDISS TOTAL = PDISS SUPPLY + PDISSDRIVE + PDIODE Eq. 7 Where: EDRIVER = Energy dissipated per switching cycle. PDRIVER = Power dissipated per switching cycle. QG = Total gate charge at VGS. VGS = Gate-to-source voltage on the MOSFET. fS = Switching frequency of the gate drive circuit. Figure 18. Typical Gate Charge vs. VGS September 15, 2015 24 Revision 1.1 Micrel, Inc. MIC4607 Decoupling and Bootstrap Capacitor Selection Decoupling capacitors are required for both the low-side (VDD) and high-side (xHB) supply pins. These capacitors supply the charge necessary to drive the external MOSFETs and also minimize the voltage ripple on these pins. The capacitor from xHB to xHS has two functions: it provides decoupling for the high-side circuitry and also provides current to the high-side circuit while the highside external MOSFET is on. Ceramic capacitors are recommended because of their low impedance and small size. Z5U type ceramic capacitor dielectrics are not recommended because of the large change in capacitance over temperature and voltage. A minimum value of 0.1µF is required for CB (xHB to xHS capacitors) and 1µF for the VDD capacitor, regardless of the MOSFETs being driven. Larger MOSFETs may require larger capacitance values for proper operation. The voltage rating of the capacitors depends on the supply voltage, ambient temperature and the voltage derating used for reliability. 25V rated X5R or X7R ceramic capacitors are recommended for most applications. The minimum capacitance value should be increased if low voltage capacitors are used because even good quality dielectric capacitors, such as X5R, will lose 40% to 70% of their capacitance value at the rated voltage. The power dissipated in the driver equals the ratio of RON and ROFF to the external resistive losses in RG and RG_FET. Letting RON = ROFF, the power dissipated in the driver due to driving the external MOSFET is: PDISSDRIVER = PDRIVER R ON R ON + R G + R G _ FET Eq. 8 There are six MOSFETs driven by the MIC4607. The power dissipation for each of the drivers must be calculated and summed to obtain the total driver diode power dissipation for the package. In some cases, the high-side FET of one phase may be pulsed at a frequency, fS, while the low-side FET of the other phase is kept continuously on. Since the MOSFET gate is capacitive, there is no driver power if the FET is not switched. The operation of all driver outputs must be considered to accurately calculate power dissipation. The die temperature can be calculated after the total power dissipation is known. TJ = TA + PDISS TOTAL × θ JA Placement of the decoupling capacitors is critical. The bypass capacitor for VDD should be placed as close as possible between the VDD and VSS pins. The bypass capacitor (CB) for the xHB supply pin must be located as close as possible between the xHB and xHS pins. The etch connections must be short, wide, and direct. The use of a ground plane to minimize connection impedance is recommended. Refer to the “Grounding, Component Placement and Circuit Layout” sub-section for more information. Eq. 9 Where: TA = Maximum ambient temperature. TJ = Junction temperature (°C). PDISS TOTAL = Total power dissipation of the MIC4607. θJA = Thermal resistance from junction to ambient air. The voltage on the bootstrap capacitor drops each time it delivers charge to turn on the MOSFET. The voltage drop depends on the gate charge required by the MOSFET. Most MOSFET specifications specify gate charge versus VGS voltage. Based on this information and a recommended ΔVHB of less than 0.1V, the minimum value of bootstrap capacitance is calculated as: Other Timing Considerations Make sure the input signal pulse width is greater than the minimum specified pulse width. An input signal that is less than the minimum pulse width may result in no output pulse or an output pulse whose width is significantly less than the input. CB ≥ The maximum duty cycle (ratio of high-side on-time to switching period) is controlled by the minimum pulse width of the low side and by the time required for the CB capacitor to charge during the off-time. Adequate time must be allowed for the CB capacitor to charge up before the high-side driver is turned on. September 15, 2015 QGATE ∆VHB Eq. 10 Where: QGATE = Total gate charge at VHB. ∆VHB = Voltage drop at the HB pin. 25 Revision 1.1 Micrel, Inc. MIC4607 If the high-side MOSFET is not switched but held in an on state, the voltage in the bootstrap capacitor will drop due to leakage current that flows from the HB pin to ground. This current is specified in the EC table. In this case, the value of CB is calculated as: CB ≥ IHBS × t ON ∆VHB It is important to note that capacitor CB must be placed close to the xHB and xHS pins. This capacitor not only provides all the energy for turn-on but it must also keep xHB pin noise and ripple low for proper operation of the high-side drive circuitry. Eq. 11 Where: IHBS = Maximum xHB pin leakage current. tON = maximum high-side FET on-time. The larger value of CB from Equation 10 or Equation 11 should be used. Grounding, Component Placement and Circuit Layout Nanosecond switching speeds and ampere peak currents in and around the MIC4607 driver require proper placement and trace routing of all components. Improper placement may cause degraded noise immunity, false switching, excessive ringing, or circuit latch-up. Figure 19. Turn-On Current Paths Figure 20 shows the critical current paths when the driver outputs go low and turn off the external MOSFETs. Short, low-impedance connections are important during turn-off for the same reasons given in the turn-on explanation. Current flowing through the internal diode replenishes charge in the bootstrap capacitor, CB. Figure 19 shows the critical current paths of the high- and low-side driver when their outputs go high and turn on the external MOSFETs. It also helps demonstrate the need for a low impedance ground plane. Charge needed to turn-on the MOSFET gates comes from the decoupling capacitors CVDD and CB. Current in the low-side gate driver flows from CVDD through the internal driver, into the MOSFET gate, and out the source. The return connection back to the decoupling capacitor is made through the ground plane. Any inductance or resistance in the ground return path causes a voltage spike or ringing to appear on the source of the MOSFET. This voltage works against the gate drive voltage and can either slow down or turn off the MOSFET during the period when it should be turned on. Current in the high-side driver is sourced from capacitor CB and flows into the xHB pin and out the xHO pin, into the gate of the high side MOSFET. The return path for the current is from the source of the MOSFET and back to capacitor CB. The high-side circuit return path usually does not have a low-impedance ground plane so the etch connections in this critical path should be short and wide to minimize parasitic inductance. As with the low-side circuit, impedance between the MOSFET source and the decoupling capacitor causes negative voltage feedback that fights the turn-on of the MOSFET. September 15, 2015 Figure 20. Turn-Off Current Paths 26 Revision 1.1 Micrel, Inc. MIC4607 Motor Applications Figure 21 illustrates an automotive motor application. The 12V battery input voltage can see peaks as high as 60V during a load dump event. The 85V-rated MIC4607drives 6 MOSFETs that provide power to the BLDC motor. Figure 22 illustrates an off-line motor application. Adding an off-line power supply to the front end allow the MIC4607 to be used in applications such as blenders and other small white goods as well as ceiling fan applications. The circuit consists of an MIC38C44 based AC/DC power supply, that is used to generate 24VDC to power a BLDC motor. The MIC4607 drives the six MOSFETs that provide power to the motor. A current-sense resistor senses the peak motor current. The voltage across this resistor is monitored by the OC circuit in the MIC4607, which provides overcurrent protection for the application. The 120V rating of the MIC5281 series of LDOs provide input surge voltage protection, while regulating the battery voltage down to 3.3V and 10V – 12V for the microcontroller and gate driver respectively. This circuit can also be used for power tool applications, where the battery voltage carries high-voltage peaks and surges. The MIC4607 can also be used in low and mid-voltage inverter applications. Figure 24 shows how power generated by a spinning (or breaking) motor can be used to generate DC power to a load or provide power for battery-charging applications. Figure 22 is a block diagram for a 24V motor drive application. The regulated 24V bus allows the use of lower input voltage LDOs, such as the MIC5239-3.3 and MIC5234. This circuit configuration can be used in industrial applications. Figure 21. Automotive or Power Tool Application September 15, 2015 27 Revision 1.1 Micrel, Inc. MIC4607 Figure 22. Industrial Motor Driver Figure 23. Blender Motor Drive Application Diagram September 15, 2015 28 Revision 1.1 Micrel, Inc. MIC4607 Figure 24. Three-Phase Synchronous Rectification September 15, 2015 29 Revision 1.1 Micrel, Inc. MIC4607 Typical Application Schematic (MIC4607-1 Version, HI/LI Inputs) MIC4607–1 Version, HI/LI Inputs September 15, 2015 30 Revision 1.1 Micrel, Inc. MIC4607 Typical Application Schematic (Continued) (MIC4607-2 Version, PWM Inputs) MIC4607-2 Version, PWM Inputs September 15, 2015 31 Revision 1.1 Micrel, Inc. MIC4607 Bill of Materials Item Part Number C1, C8, C9, C11 0805YD106MAT2A C2 06033D105MAT2A Manufacturer (8) AVX AVX (9) Qty. 10µF Ceramic Capacitor, 16V, X5R, Size 0805 4 1µF Ceramic Capacitor, 25V, X5R, Size 0603 1 4.7µF Ceramic Capacitor, 100V, X7S, Size 1210 3 C3, C4, C5 C3225X7S2A475M200AB C6 B41858-C9107-M000 TDK 100µF Aluminum Electrolytic Capacitor, 100V 1 C13 06035C333MAT2A AVX 33nF Ceramic Capacitor, 50V, X7R, Size 0603 1 C17 06035C102MAT2A AVX 1nF Ceramic Capacitor, 50V, X7R, Size 0603 1 Q1, Q2, Q3, Q4, Q5, Q6 AM7414NA N-Channel MOSFET, 100V 6 R1, R4, R5, R6, R7, R8, R18, R19, R20 CRCW06030000FRT1 0Ω, Size 0603 9 R9, R10, R11 CRCW06034R99FRT1 Vishay 4.99Ω, 1%, Size 0603 3 R13 CRCW06034990FRT1 Vishay 499Ω, 1%, Size 0603 1 R2, R3 CRCW06031003FRT1 Vishay 100kΩ, 1%, Size 0603 2 0.05Ω, 1W, Size 1210 2 3.01Ω, 1%, Size 0603 3 Schottky Diode, 30V, 350mA, SOD-323 3 85V, Three-Phase MOSFET Driver with Adaptive Dead-Time, Anti-Shoot-Through and Overcurrent Protection 1 R12, R14 ERJ-L14KF50MU R15, R16, R17 CRCW06033R01FRT1 D1, D2, D3 SD103BWS MIC4607-1YML U1 MIC4607-2YML TDK Description Analog Power (10) (11) Vishay Panasonic (12) Vishay Diodes, Inc. (13) (14) Micrel, Inc. Notes: 8. AVX: www.avx.com. 9. TDK: www.tdk.com. 10. Analog Power: www.analogpowerinc.com. 11. Vishay: www.vishay.com. 12. Panasonic: www.industrial.panasonic.com. 13. Diodes, Inc.: www.diodes.com. 14. Micrel, Inc.: www.micrel.com. September 15, 2015 32 Revision 1.1 Micrel, Inc. MIC4607 PCB Layout Recommendations Top Layer Bottom Layer September 15, 2015 33 Revision 1.1 Micrel, Inc. MIC4607 Package Information and Recommended Land Pattern(15) 28-Pin 4mm × 5mm QFN (ML) Note: 15. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com. September 15, 2015 34 Revision 1.1 Micrel, Inc. MIC4607 Package Information and Recommended Land Pattern(15) (Continued) 28-Pin TSSOP (TS) September 15, 2015 35 Revision 1.1 Micrel, Inc. MIC4607 MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products. Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network of distributors and reps worldwide. Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2015 Micrel, Incorporated. September 15, 2015 36 Revision 1.1