L6917B Datasheet, PDF (1/33 Pages) STMicroelectronics – 5 BIT PROGRAMMABLE DUAL-PHASE CONTROLLER

L6917B
5 BIT PROGRAMMABLE DUAL-PHASE CONTROLLER
s 2 PHASE OPERATION WITH
SYNCRHONOUS RECTIFIER CONTROL
s ULTRA FAST LOAD TRANSIENT RESPONSE
s INTEGRATED HIGH CURRENT GATE
DRIVERS: UP TO 2A GATE CURRENT
s TTL-COMPATIBLE 5 BIT PROGRAMMABLE
OUTPUT COMPLIANT WITH VRM 9.0
s 0.8% INTERNAL REFERENCE ACCURACY
s 10% ACTIVE CURRENT SHARING
ACCURACY
s DIGITAL 2048 STEP SOFT-START
s OVERVOLTAGE PROTECTION
s OVERCURRENT PROTECTION REALIZED
USING THE LOWER MOSFET'S R_dsON OR A
SENSE RESISTOR
s 300 kHz INTERNAL OSCILLATOR
s OSCILLATOR EXTERNALLY ADJUSTABLE
UP TO 600kHz
s POWER GOOD OUTPUT AND INHIBIT
FUNCTION
s REMOTE SENSE BUFFER
s PACKAGE: SO-28
APPLICATIONS
s POWER SUPPLY FOR SERVERS AND
WORKSTATIONS
s POWER SUPPLY FOR HIGH CURRENT
MICROPROCESSORS
s DISTRIBUTED DC-DC CONVERTERS
SO-28
ORDERING NUMBERS:L6917BD
L6917BDTR (Tape & Reel)
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.
BLOCK DIAGRAM
PGOOD
ROSC / INH
2 PHASE
OSCILLATOR
DIGITAL
SOFT START
VID4
VID3
VID2
VID1
VID0
DAC
FBG
FBR
10k
10k
10k
10k
REMOTE
BUFFER
LOGIC
AND
PROTEC TIONS
VCC
VCC DR
CH1 OVER
CU RR EN T
CH2 OVER
CU RR EN T
IFB
ERR OR
AMPLIFIER
SGND
VCCD R
HS
PWM1
-
+
CH 1 OVER
CU RR EN T
LS
+ TOTAL
CU RR EN T
AVG
CU RR EN T
<>
CURRENT
READ ING
CURRENT
READ ING
CH 2 OVER
CU RR EN T
LS
+
-
PWM2
HS
Vcc
BOOT1
UGATE1
PH AS E1
LGATE1
ISEN1
PGNDS1
PGND
PGNDS2
ISEN2
LGATE2
PH AS E2
UGATE2
BOOT2
September 2002
VSEN
FB
COMP
Vcc
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