A3974 Datasheet, PDF (4/12 Pages) Allegro MicroSystems – DMOS Dual Full-Bridge PWM Motor Driver

A3974
DMOS Dual Full-Bridge PWM Motor Driver
FUNCTIONAL BLOCK DIAGRAM
VDD
LOGIC
SUPPLY
CHARGE PUMP
BANDGAP
VDD
CREG
TSD
UNDER-
VOLTAGE &
FAULT DETECT
CONTROL LOGIC
ENABLE1
OSC
CLOCK
DATA
STROBE
FIXED OFF
PROGRAMMABLE ^BLANK
PWM TIMER
DECAY
SERIAL
PORT
FIXED OFF
PROGRAMMABLE ^BLANK
PWM TIMER
DECAY
CHARGE
PUMP
VBB1
+
LOAD
SUPPLY1
BANDGAP
REGULATOR
VREG
OUT1A
ZERO CURRENT DETECT
CURRENT SENSE
REFERENCE
BUFFER &
DIVIDER
CHARGE
PUMP
OUT1B
SENSE1
CS1
RS1
REF1
LOAD
SUPPLY2
+
VREF
VBB2
SLEEP
MODE
ENABLE2
CONTROL LOGIC
TO PWM TIMER
OUT2A
ZERO CURRENT DETECT
CURRENT SENSE
REFERENCE
BUFFER &
DIVIDER
OUT2B
SENSE2
CS2
RS2
REF2
VREF2
Dwg. FP-048-1
Allegro MicroSystems, Inc.
3
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
Copyright © 2001 Allegro MicroSystems, Inc.
1.508.853.5000; www.allegromicro.com