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Preliminary
Features
* * * * *
HT82P604B DC-DC Converter
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Operating voltage: 5V~12V Drives two N-Channel MOSFETs Simple single-loop control design - Voltage-mode PWM control Fast transient response - High-bandwidth error amplifier - Full 0% to 100% duty ratio Excellent output voltage regulation - 1% over line voltage and temperature
* * *
5 bit digital-to-analog output voltage selection - Wide range -1.3V to 3.5V - 0.1V binary steps from 2.1V to 3.5V - 0.05V binary steps from 1.3V to 2.05V Power-good output voltage monitor Over-voltage and over-current sensing element, uses MOSFETs rDS (ON) Small converter size - Constant frequency operation - 200kHz free-running oscillator programmable from 50kHz to over 1MHz
Applications
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Power supply for PentiumTM, PentiumTM Pro, PowerPCTM and AlphaTM Microprocessors
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High-power5Vto3.xVDC-DCregulators Low-voltage distributed power supplies
General Description
The HT82P604B provides complete control and protection for a DC-DC converter optimized for high performance microprocessor applications. It is designed to drive two N-Channel MOSFETs in a synchronous-rectified buck topology. The HT82P604B integrates all of the control, output adjustment, monitoring and protection functions into a single package. The output voltage of the converter is easily adjusted and precisely regulated. The HT82P604B includes a 5-input digital-to-analog converter (DAC) that adjusts the output voltage from 2.1V to 3.5V in 0.1V increments and from 1.3V to 2.05V in 0.05V steps. The precision reference and voltage-mode regulator hold the selected output voltage to within 1% over temperature and line voltage variations. The HT82P604B provides simple, single feedback loop, voltage-mode control with fast transient response. It includes a 200kHz free-running triangle-wave oscillator that is adjustable from below 50kHz to over 1MHz. The error amplifier features a 15MHz gain-bandwidth product and 6V/ms slew rate which enables high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 100%. The HT82P604B monitors the output voltage with a window comparator that tracks the DAC output and issues a Power Good signal when the output is within 10%. The HT82P604B protects against over-current conditions by inhibiting PWM operation. Built-in over-voltage protection triggers an external SCR to crowbar the input supply. The HT82P604B monitors the current by using the rDS (ON) of the upper MOSFET which eliminates the need for a current sensing resistor.
Pentium is a trademark of Intel Corporation
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March 23, 2000
Preliminary
Pin Assignment
VSEN 1 2 3 4 5 6 7 8 9 10 OCSET SS V ID 0 V ID 1 V ID 2 V ID 3 V ID 4 COMP FB 20 19 18 17 16 15 14 13 12 11 RT OVP VCC LG ATE PGND BOOT UGATE PHASE PGOOD GND
HT82P604B
H T82P604B 20 SO P
Pin Description
Pin No. 1 Pin Name VSEN I/O I Description This pin is connected to the converters output voltage. The PGOOD and OVP comparator circuits use this signal to report output voltage status and for overvoltage protection. Connect a resistor (ROCSET) from this pin to the drain of the upper MOSFET. ROCSET, an internal 200mA current source (IOCS), and the upper MOSFET on-resistance (rDS (ON)) set the converter over-current (OC) trip point. I ROCSET IPEAK = OCS rDS(ON) An over-current trip cycles the soft-start function. 3 SS O Connect a capacitor from this pin to ground. This capacitor, along with an internal 10mA current source, sets the soft-start interval of the converter. VID0-4 are the input pins to the 5-bit DAC. The states of these five pins program the internal voltage reference (DACOUT). The level of DACOUT sets the converter output voltage. It also sets the PGOOD and OVP thresholds. Table 1 specifies DACOUT for the 32 combinations of DAC inputs. COMP and FB are the available external pins of the error amplifier. The FB pin is the inverting input of the error amplifier and the COMP pin is the error amplifier output. These pins are used to compensate the voltage-control feedback loop of the converter. Signal ground for the IC. All voltage levels are measured with respect to this pin.
2
OCSET
I
4~8
VID0~4
I
9, 10
COMP, FB
I
11
GND
P
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March 23, 2000
Preliminary
Pin No. Pin Name I/O Description
HT82P604B
12
PGOOD
O
PGOOD is an open collector output used to indicate the status of the converter output voltage. This pin is pulled low when the converter output is not within 10% of the DACOUT reference voltage. Exception to this behavivor is the 11111 VID pin combination which disables the converter; in this case, PGOOD asserts a high level. Connect the PHASE pin to the upper MOSFET source. This pin is used to monitor the voltage drop across the MOSFET for over-current protection. This pin also provides the return path for the upper gate drive. Connect UGATE to the upper MOSFET gate. This pin provides the gate drive for the upper MOSFET. This pin provides bias voltage to the upper MOSFET driver. A bootstrap circuit may be used to create a BOOT voltage suitable to drive a standard N-Channel MOSFET. This is the power ground connection. Tie the lower MOSFET source to this pin. Connect LGATE to the lower MOSFET gate. This pin provides the gate drive for the lower MOSFET. Provide a 12V bias supply for the chip to this pin. The OVP pin can be used to drive an external SCR in the event of an overvoltage condition. This pin provides oscillator switching frequency adjustment. By placing a resistor (RT) from this pin to GND, the nominal 200kHz switching frequency is increased. 5 106 FS 200kHz + (RT to GND) R T (kW) Conversely, connecting a pull-up resistor (RT) from this pin to VCC reduces the switching frequency. 4 107 (RT to 12V) FS 200kHz + R T (kW)
13
PHASE
O
14 15 16 17 18 19
UGATE BOOT PGND LGATE VCC OVP
O I P O P O
20
RT
I
Absolute Maximum Ratings
Supply Voltage ......................................... +15V Input Voltage ............... GND-0.3 to VCC+0.3V Storage Temperature ............... -50C to 125C Operating Temperature ............ -20C to 75C
Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maximum Ratings may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability.
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Preliminary
Electrical Characteristics
Symbol Parameter Test Conditions VCC Conditions
HT82P604B
Min. Typ. Max. Unit
VCC Supply Current ICC Nominal Supply Rising VCC Threshold Falling VCC Threshold Rising VOCSET Threshold Oscillator Free Running Frequency Total Variation DVOSC Ramp Amplitude Reference and DAC DACOUT Voltage Accuracy 12V ERROR Amplifier DC Gain GBW SR Gain-Bandwidth Product Slew Rate 12V 12V 12V COMP=10pF VBOOT-VPHASE=12V, VUGATE=6V 3/4 3/4 3/4 88 15 6 3/4 3/4 3/4 dB MHz V/ms -1.0 3/4 +1.0 % 12V RT=Open 12V 6kWGate Drivers IUGATE RUGATE ILGATE RLGATE Upper Gate Source Upper Gate Sink Lower Gate Source Lower Gate Sink Over-Voltage Trip (VSEN/DACOUT) IOCSET IOVP ISS OCSET Current Source OVP Sourcing Current Soft Start Current Upper Threshold (VSEN/DACOUT) 12V 350 3/4 300 3/4 500 5.5 450 3.5 3/4 10 3/4 6.5 mA W mA W
12V ILGATE=0.3A 12V VCC=12V, VLGATE=6V 12V ILGATE=0.3V
Protection 12V 12V VOCSET=4.5VDC 12V VSEN=5.5, VOVP=0V 12V 3/4 170 60 3/4 115 200 3/4 10 120 230 3/4 3/4 % mA mA mA
Power Good 12V VSEN Rising 106 3/4 111 %
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March 22, 2000
Preliminary
Symbol Parameter Lower Threshold (VSEN/DACOUT) Hysteresis (VSEN/DACOUT) VPGOOD PGOOD Voltage Low Test Conditions VCC Conditions
HT82P604B
Min. Typ. Max. Unit 89 3/4 3/4 3/4 2 0.5 94 3/4 3/4 % % V
12V VSEN Falling 12V Upper and Lower Threshold
12V IPGOOD=-5mA
Functional Description
Output voltage program The output voltage of a HT82P604B converter is programmed to discrete levels between 1.3V and 3.5V. The voltage identification (VID) pins program an internal voltage reference (DACOUT) with a 5-bit digital-to-analog converter (DAC). The level of DACOUT also sets the PGOOD and OVP thresholds. Table 1 specifies the DACOUT voltage for the 32 combinations of open or short connections on the VID pins. The output voltage should not be adjusted while the converter is delivering power. Remove input power before changing the output voltage. Adjusting the output voltage during operation could toggle the PGOOD signal and exercise the overvoltage protection. Nominal Output VID4 VID3 VID2 VID1 VID0 Voltage Dacout 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 Pin Name Nominal Output Voltage VID4 VID3 VID2 VID1 VID0 Dacout 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1.85 1.90 1.95 2.00 2.05 0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 Pin Name
Note: 0=connected to GND or VSS, 1=OPEN Table 1 Output voltage program
5 March 23, 2000
Preliminary
Application Circuits
4mH V
IN
HT82P604B
=+5v or+12V +12V 4x1000mF
1mF 10W 0 .1 m F SS 3 1 20 4 5 6 7 8 V
O
VCC 18 M o n ito r and P r o te c tio n
OVP 19 2
1000pF OCSET PGOOD BOOT UGATE 47W 13 PHASE 4mH 2 .7 k W
0 .1 m F
VSEN RT V ID 0 V ID 1 V ID 2 V ID 3 V ID 4 FB
12 15
OSC 14 H T82P604B D /A
17 10 9 33pF 0 .0 1 m F 20kW COMP 11 GND 16
LG ATE PGND 0W
0 .1 m F
10x1000mF
560kW
20kW 22W 15kW
0 .1 m F
1kW
0 .1 m F
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March 23, 2000
Preliminary
HT82P604B
Holtek Semiconductor Inc. (Headquarters) No.3 Creation Rd. II, Science-based Industrial Park, Hsinchu, Taiwan, R.O.C. Tel: 886-3-563-1999 Fax: 886-3-563-1189 Holtek Semiconductor Inc. (Taipei Office) 5F, No.576, Sec.7 Chung Hsiao E. Rd., Taipei, Taiwan, R.O.C. Tel: 886-2-2782-9635 Fax: 886-2-2782-9636 Fax: 886-2-2782-7128 (International sales hotline) Holtek Semiconductor (Hong Kong) Ltd. RM.711, Tower 2, Cheung Sha Wan Plaza, 833 Cheung Sha Wan Rd., Kowloon, Hong Kong Tel: 852-2-745-8288 Fax: 852-2-742-8657 Copyright a 2000 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw.
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March 23, 2000

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