A3986
Dual Full-Bridge MOSFET Driver
with Microstepping Translator
Functional Block Diagram
+5 V
VDD
VBB
V
MOTOR
VREG
Bandgap
Regulator
CREG
V
REG
Phase 1A
Bridge1
CBOOT1A
REF
V
REF
High-Side
Drive
V
REG
DAC
STEP
PWM Latch
Blanking
Mixed Decay
Low-Side
Drive
GL1A
LSS1
SENSE1
Phase 1B
Low-Side
Drive
Phase 1
MS2
Phase 1
Control Logic
High-Side
Drive
GH1B
CBOOT1B
C1B
GL1B
S1B
RSENSE1
P
P
C1A
GH1A
S1A
RGH1A
RGH1B
RGL1A
RGL1B
DIR
MS1
Translator
PFD1
Phase 2A
V
MOTOR
Bridge2
C2A
CBOOT2A
PFD2
Phase 2
Control Logic
ENABLE
Phase 2
High-Side
Drive
V
REG
Low-Side
Drive
GH2A
S2A
RGH2A
RGH2B
GL2A
LSS2
SENSE2
RGL2A
RGL2B
RESET
PWM Latch
Blanking
Mixed Decay
Phase 2B
Low-Side
Drive
GL2B
S2B
GH2B
CBOOT2B
C2B
RSENSE2
P
SR
DAC
OSC
ROSC
Protection
UVLO
TSD
V
REF
High-Side
Drive
GND
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
3
ALLEGRO [ ALLEGRO MICROSYSTEMS ]
