L6917B
5 BIT PROGRAMMABLE DUAL-PHASE CONTROLLER
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2 PHASE OPERATION WITH
SYNCRHONOUS RECTIFIER CONTROL
ULTRA FAST LOAD TRANSIENT RESPONSE
INTEGRATED HIGH CURRENT GATE
DRIVERS: UP TO 2A GATE CURRENT
TTL-COMPATIBLE 5 BIT PROGRAMMABLE
OUTPUT COMPLIANT WITH VRM 9.0
0.8% INTERNAL REFERENCE ACCURACY
10% ACTIVE CURRENT SHARING
ACCURACY
DIGITAL 2048 STEP SOFT-START
OVERVOLTAGE PROTECTION
OVERCURRENT PROTECTION REALIZED
USING THE LOWER MOSFET'S R
dsON
OR A
SENSE RESISTOR
300 kHz INTERNAL OSCILLATOR
OSCILLATOR EXTERNALLY ADJUSTABLE
UP TO 600kHz
POWER GOOD OUTPUT AND INHIBIT
FUNCTION
REMOTE SENSE BUFFER
PACKAGE: SO-28
SO-28
ORDERING NUMBERS:L6917BD
L6917BDTR (Tape & Reel)
APPLICATIONS
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POWER SUPPLY FOR SERVERS AND
WORKSTATIONS
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POWER SUPPLY FOR HIGH CURRENT
MICROPROCESSORS
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DISTRIBUTED DC-DC CONVERTERS
BLOCK DIAGRAM
ROSC / INH
DESCRIPTION
The device is a power supply controller specifically
designed to provide a high performance DC/DC con-
version for high current microprocessors.
The device implements a dual-phase step-down con-
troller with a 180° phase-shift between each phase.
A precise 5-bit digital to analog converter (DAC) al-
lows adjusting the output voltage from 1.100V to
1.850V with 25mV binary steps.
The high precision internal reference assures the se-
lected output voltage to be within ±0.8%. The high
peak current gate drive affords to have fast switching
to the external power mos providing low switching
losses.
The device assures a fast protection against load
over current and load over/under voltage. An internal
crowbar is provided turning on the low side mosfet if
an over-voltage is detected. In case of over-current,
the system works in Constant Current mode.
SGND
VCCDR
BOOT1
LOGIC PWM
ADAPTIVE ANTI
CROSS-CONDUCTION
PGOOD
2 PHASE
OSCILLATOR
PWM1
UGATE1
HS
PHASE1
-
CURRENT
CORRECTION
+
DIGITAL
SOFT START
CH 1 OVER
CURRENT
LGATE1
LS
ISEN1
VCC
VCCDR
LOGIC
AND
PROTECTIONS
TOTAL
CURRENT
+
<>
CURRENT
READING
PGNDS1
PGND
VID4
VID3
VID2
VID1
VID0
CH1 OVER
CURRENT
AVG
CURRENT
DAC
CH2 OVER
CURRENT
CURRENT
READING
PGNDS2
ISEN2
LOGIC PWM
ADAPTIVE ANTI
CROSS-CONDUCTION
CH 2 OVER
CURRENT
LGATE2
LS
10k
10k
10k
REMOTE
BUFFER
+
IFB
FBG
FBR
CURRENT
CORRECTION
-
ERROR
AMPLIFIER
PHASE2
PWM2
UGATE2
HS
10k
Vcc
BOOT2
VSEN
FB
COMP
Vcc
September 2002
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STMICROELECTRONICS [ STMICROELECTRONICS ]
