AP2002 Synchronous PWM Controller Features General Description - Single or Dual Supply Application - 0.8V + 1.0% Voltage Reference. - Fast transient response. - Synchronous operation for high efficiency (95%) - On-chip power good, OVP protect. - Small size with minimum external components - Soft Start and enable functions - Industrial temperature range - Under Voltage Lockout function - SOP-14L package The AP2002 is a low-cost, full featured, and synchronous voltage-mode controller designed for use in single ended power supply applications where efficiency is of primary concern. This synchronous operation allows the elimination of heat sinks in many applications. The AP2002 is ideal for implementing DC/DC converters that is needed for the power advanced microprocessors in low cost systems, or in distributed power applications where efficiency is important. Internal level-shift, high-side drive circuitry, and preset shoot-thru control, allows the use of inexpensive N-channel power switches. AP2002 features include temperature compensated voltage reference, an internal 200Khz virtual frequency oscillator, under voltage lockout protection, soft-start function and current sense comparator circuitry. Power good signaling, shutdown, and over voltage protection are also provided by AP2002. Applications - Microprocessor core supply - Low cost synchronous applications - Voltage Regulator Modules (VRM) - DDR termination supplies - Networking power supplies - Sequenced power supplies Pin Assignment Pin Descriptions (Top View) VCC PWRGD OVP OCSET PHASE DRVH PGND 1 14 2 13 3 12 4 AP2002 11 5 10 6 9 7 8 GND SS/SHDN COMP SENSE BSTH BSTL DRVL VCC Chip supply voltage Logic high indicates correct output voltage (open drain output) Over voltage protection Sets the converter over-current trip point Input from the phase node between the MOSFETs High side driver output Power ground Low side driver output Bootstrap, low side driver Bootstrap, high side driver Voltage sense input Compensation pin Soft start, a capacitor to ground sets the slow start time Signal ground OVP OCSET PHASE DRVH PGND DRVL BSTL BSTH SENSE COMP Ordering Information Package S: SOP-14L Description PWRGD SOP-14L AP2002 X Name X X Lead Free Packing Blank : Tube Blank : Normal L : Lead Free Package A : Taping SS/ SHDN GND This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev. 0.2 Apr 14, 2004 1/7 AP2002 Synchronous PWM Controller Block Diagram VCC 200uA Vbg + - Vcc OCSET + Under Voltage +10% - 10% 0.8V +20% + - PWRGD Over Current - + Oscillator One-Shot + - OVP COMP SENSE PWM Error Amp + - Vbg BSTH DRVH DRVH Vcc 10uA 0.5V Cross Current Control S R Ob + - PHASE VCC BSTL SS/SHDN Foult 2uA 0.6V GND DRVL DRVL + - PGND Absolute Maximum Ratings Symbol VIN VPHASE ΘJC Parameter Max. Unit -1 to 14 V PGND to GND + 0.5 V PHASE to GND -1 to 18 V BSTH to PHASE 14 VCC, BSTL to GND Thermal Resistance Junction to Case ΘJA Thermal Resistance Junction to Ambient TOP Operating Temperature Range TST TLEAD Storage Temperature Range Lead Temperature (Soldering) 10 Sec. Anachip Corp. www.anachip.com.tw V 45 o C/W 115 o C/W -40 to +85 o C -65 to +150 o C 300 o C Rev. 0.2 Apr 14, 2004 2/7 AP2002 Synchronous PWM Controller Electrical Characteristics Unless specified: VCC = 4.75V to 12.6V; GND = PGND = 0V; FB = VO; VBSTL = 12V; VBSTH-PHASE = 12V; TJ = 25oC Symbol Parameter Conditions Min. VCC 4.2 Typ. Max. Unit 12.6 V 10 mA Power Supply VCC Supply Voltage ICC Supply Current ∆VLINE Line Regulation 6 VO = 2.5V 0.5 % Error Amplifier AOL Gain (AOL) 50 IB Input Bias 5 8 uA dB 220 KHz Oscillator FOSC DCMAX Oscillator Frequency 180 200 Oscillator Max Duty Cycle 90 95 % MOSFET Drivers IDRVH DRVH Source/Sink IDRVL DRVL Source/Sink VBSTH – VDRVH =4.5V VDRVH – VPHASE = 2V VBSTH – VDRVL = 4.5V VDRVL – VPGND = 2V 1 A 1 A Protection DTH OVP Threshold 20 IOVP OVP Source Current DPG Power Good Threshold 88 112 % TDEAD Dead Time 45 100 nS IOCSET Over Current Set Isink VOVP = 3V 2.0V < VOCSET < 12V % 10 mA 180 200 220 uA 0.792 0.8 0.808 V +1 % Reference VREF Reference Voltage Accuracy 0oC to 70oC -1 Soft Start ISSC Charge Current ISSD Discharge Current Under voltage lockout (UVLO) Upper threshold voltage VUT (VCC) Lower threshold voltage VLWT (VCC) VHT Hysteresis (VCC) VSS = 1.5V 8.0 10 12 uA VSS = 1.5V 1.3 2 2.7 uA 4.2 4.4 V IO(REF) = 0.1mA TA = 25ºC 4.0 V 200 mV Note 1. Specification refers to Typical Application Circuit. Note 2. This device is ESD sensitive. Use of standard ESD handling precautions is required. Anachip Corp. www.anachip.com.tw Rev. 0.2 Apr 14, 2004 3/7 AP2002 Synchronous PWM Controller Typical Application Circuit (1) +12V +5V R1 1k R2 10k PWRGD C1 0.1 C2 0.1 1 VCC GND 14 C3 0.1 2 PWRGD SS/SHDN 13 R3 1k C8 680/ 16V + - VIN 5V/12V SHDN R7 3 OVP OVP C6 C7 680/ 680/ 16V 16V C5 0.1 R4 10 4 OCSET C9 COMP 12 47k 18nF SENSE 11 5 PHASE BSTH 10 6 DRVH BSTL 9 7 PGND DRVL 8 R9 270* 0.1u C4 R8 120 R5 1.2O R6 1.2O L1 Q1 PFD3000 3.3uH Q2 PFD3000 D1 Option Vout=2.5V + C10 0.1 R10 4.7O C12 680/ 16V C11 680/ 16V C13 C14 680/ 680/ 16V 16V - Note: *Vout =Vref x (1+R9/R8) 5V & 12V dual input circuit (2) +5V R1 1k R2 10k PWRGD OVP C1 0.1 C2 0.1 R3 1k R4 10 C5 0.1 D2 1 VCC GND 14 2 PWRGD SS/SHDN 13 3 OVP COMP 12 C3 0.1 R7 C6 C7 680/ 680/ 16V 16V SENSE 11 5 PHASE BSTH 10 6 DRVH BSTL 9 7 PGND DRVL 8 + - VIN 5V or 12V SHDN C9 R9 270* 47k 18nF 4 OCSET C8 680/ 16V C4 0.1u R5 1.2 Ω R6 1.2 Ω C9 Q1 L1 0.1 PFD3000 3.3uH Q2 PFD3000 R8 120 + D1 Option C10 0.1 R10 4.7 Ω C11 C12 680/ 680/ 16V 16V C13 680/ 16V C14 Vout=2.5V* 680/ 16V - Note: * Vout=Vref x (1+R9/R8) 5V or 12V input with Bootstrapped BSTH Anachip Corp. www.anachip.com.tw Rev. 0.2 Apr 14, 2004 4/7 AP2002 Synchronous PWM Controller Function Description Synchronous Buck Converter Primary VCORE power is provided by a synchronous, voltage-mode pulse width modulated (PWM) controller. This section has all the features required to build a high efficiency synchronous buck converter, including “Power Good” flag, shutdown, and cycle-by-cycle current limit. Power Good The power good function is to confirm that the regulator outputs are within +/- 10% of the programmed level. PWRGD remains high as long as this condition is met. PWRGD is connected to an internal open collector NPN transistor. Soft Start The output voltage of the synchronous converter is set and controlled by the output of the error amplifier. The external resistive divider reference voltage is derived from an internal trimmed band-gap voltage reference. The inverting input of the error amplifier receives its voltage from the SENSE pin. Initially, SS/ SHDN sources 10uA of current to charge an external capacitor. The outputs of the error amplifiers are clamped to a voltage proportional to the voltage on SS/ SHDN . This limits the on-time of the high-side MOSFET, thus leading to a controlled ramp-up of the output voltages. The internal oscillator uses an on-chip capacitor and trimmed precision current sources to set the oscillation frequency to 200KHz. The triangular output of the oscillator sets the reference voltage at the inverting input of the comparator. When the oscillator output voltage drops below the error amplifier output voltage, the comparator output goes high. This pulls DRVL low, turning off the low-side FET, and DRVH is pulled high, turning on the high-side FET (once the cross-current control allows it). When the oscillator voltage rises back above the error amplifier output voltage, the comparator output goes low. This pulls DRVH low, turning off the high-side FET, and DRVL is pulled high, turning on the low-side FET (once the cross-current control allows it). RDS(ON) Current Limiting The current limit threshold is setting by connecting an external resistor from VCC supply to OCSET. The voltage drop across this resistor is due to the 200uA internal sink sets the voltage at the pin. This voltage is compared to the voltage at the PHASE node. This comparison is made only when the high-side drive is high to avoid false current limit triggering due to un-contributing measurements from the MOSFETs off-voltage. When the voltage at PHASE is less than the voltage at OCSET, an over-current condition occurs and the soft start cycle is initiated. The synchronous switch turns off and SS/ SHDN starts to sink 2uA. When SS/ SHDN reaches 0.8V, it then starts to source 10uA and a new cycle begins. As SENSE increases, the output voltage of the error amplifier decreases. This causes a reduction in the on-time of the high-side MOSFET connected to DRVH, hence lowering the output voltage. Under Voltage Lockout The under voltage lockout circuit of the AP2002 assures that the high-side MOSFET driver outputs remain in the off state whenever the supply voltage drops below set parameters. Lockout occurs if VCC falls below 4.1V. Normal operation resumes once VCC rises above 4.2V. Over-Voltage Protection The over-voltage protection pin (OVP) is high only when the voltage at SENSE is 20% higher than the target value programmed by the external resistor divider. The OVP pin is internally connected to a PNP’s collector. Anachip Corp. www.anachip.com.tw Rev. 0.2 Apr 14, 2004 5/7 AP2002 Synchronous PWM Controller Function Description (Continued) Hiccup Mode voltage will begin to decrease as the 2uA of current discharge the external capacitor. When the During power up, the SS/ SHDN pin is internally pulled low until VCC reaches the under-voltage lockout level of 4.2V. Once VCC has reached 4.2V, soft-start voltage reaches 0.8V, the SS/ SHDN pin will begin to source 10uA and begin to charge the external capacitor causing the soft-start voltage to rise again. Again, when the soft-start voltage reaches the level of the internal oscillator, switching will occur. the SS/ SHDN pin is released and begins to source 10uA of current to the external soft-start capacitor. As the soft-start voltage rises, the output of the internal error amplifier is clamped to this voltage. When the error signal reaches the level of the internal triangular oscillator, which swings from 1V to 2V at a fixed frequency of 200KHz, switching occurs. As the error signal crosses over the oscillator signal, the duty cycle of the PWM signal continues to increase until the output comes into regulation. If an over-current condition has not occurred the soft-start voltage will continue to rise and level off at about 2.2V. If the over-current condition is no longer present, normal operation will continue. If the over-current condition is still present, the SS/ SHDN pin will again begin to sink 2uA. This cycle will continue indefinitely until the over-current condition is removed. In conclusion, above is shown a typical “12V Application Circuit” which has a BSTH voltage derived by bootstrapping input voltage to the PHASE node through diode D1. This circuit is very useful in cases where only input power of 5V(or 12V) is available. An over-current condition occurs when the high-side drive is turned on, but the PHASE node does not reach the voltage level set at the OCSET pin. The PHASE node is sampled only once per cycle during the vally of the triangular oscillator. Once an over-current occurs, the high-side drive is turned off and the low-side drive turns on and the In order to prevent substrate glitching, a small-signal diode should be placed in close proximity to the chip with cathode connected to PHASE and anode connected to PGND. SS/ SHDN pin begins to sink 2uA. The soft-start Marking Information ( Top View ) 8 14 AC AP2002 YY WW X X Logo Part No. 1 ID code: internal Blank: normal L: Lead Free Package 7 Xth week: 01~52 Year: "01" = 2001 "02" = 2002 ~ SOP-14L Anachip Corp. www.anachip.com.tw Rev. 0.2 Apr 14, 2004 6/7 AP2002 Synchronous PWM Controller Package Information 0.010 (1) Package Type: SOP-14L E1 E Gage Plane Pin 1 indent L Θ Detail A 7o(4x) 0.015x45 o D A A2 7o (4x) C e b A1 y Detail A A Dimensions In Millimeters Min. Nom. Max. 1.47 1.60 1.730 A1 0.10 - 0.250 0.0040 - 0.0100 A2 - 1.45 - - 0.057 - b 0.33 0.41 0.510 0.0130 0.016 0.0200 C 0.19 0.20 0.250 0.0075 0.008 0.0098 Symbol Dimensions In Inches Min. Nom. Max. 0.0580 0.063 0.0680 D 8.53 8.64 8.740 0.3360 0.340 0.3440 E 5.80 6.00 6.200 0.2283 0.236 0.2441 E1 3.80 3.90 3.990 0.1496 0.153 0.1571 e - 1.27 - - 0.050 - L Y 0.38 0.71 1.270 0.0150 0.028 0.0500 - - 0.076 - - 0.0030 θ O 0 O 8 Anachip Corp. www.anachip.com.tw O 0 8O Rev. 0.2 Apr 14, 2004 7/7