A3941 Allegro MicroSystems, Inc., A3941 Datasheet - Page 9

• Manufacturer Part Number: A3941
• Description: Automotive Full Bridge MOSFET Driver
• Manufacturer: Allegro MicroSystems, Inc.

A3941
Table 1. Phase Control Truth Table
Table 2. PWM Options
a
b
c
X = don’t care (same for input 1 or input 0), HS = high-side FET active, LS = low-side FET active, Z = high impedance, both FETs off
With SR disabled, braking is only effective in one direction when sufficient forward voltage is available to allow the diode to conduct.
PWMH
X indicates don’t care condition. The action is the same for input 1 or input 0.
PWM Effect indicates the effect on the load current direction or the equivalent action.
SR
1
1
0
1
0
0
1
1
0
X
X
0
1
1
0
0
PWML
PWMH
PWM
PWM
PWM
1
1
1
0
1
1
0
0
0
1
1
1
0
Inputs
PHASE
PWML
PWM
PWM
PWM
X
X
X
1
0
1
0
1
0
a
1
1
1
0
Inputs
SR
X
X
1
1
0
0
0
0
X
PHASE
PWM
X
1
0
1
0
1
0
1
0
1
0
HA
H
H
H
L
L
L
L
L
L
LA
A to B
A to B
B to A
A to B
B to A
A to B
B to A
A to B
B to A
A to B
B to A
Coast
100%
H
H
H
L
L
L
L
L
L
PWM Effect
HB
Automotive Full Bridge MOSFET Driver
H
H
H
L
L
L
L
L
L
Brake
Brake
B to A
Coast
Brake
Brake
Coast
0%
LB
b
H
H
H
L
L
L
L
L
L
c
c
Decay
Slow
Slow
Slow
Slow
SA
HS
HS
HS
Fast
Fast
Fast
LS
LS
LS
Ouputs
Z
Z
Z
SB
HS
HS
HS
LS
LS
LS
Z
Z
Z
Full four-quadrant control, zero average load current at 50% PWM
Fast decay, diode recirculation or coast
High-side PWM, low-side MOSFET recirculation
Low-side PWM, high-side MOSFET recirculation
High-side PWM, low-side diode recirculation
Low-side PWM, high-side diode recirculation
Coast, all MOSFETs off
Bridge driven with A high and B low
Bridge driven with B high and A low
Slow decay, both low-side drivers on or low-side brake
Slow decay, both high-side drivers on or high-side brake
Slow decay, current flow A to B, low-side diode rectification
Slow decay, current flow B to A, low-side diode rectification
Slow decay, current flow A to B, high-side diode rectification
Slow decay, current flow B to A, high-side diode rectification
Fast decay, diode rectification or coast
Mode of Operation
Mode of Operation
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
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