A3932
Three-Phase Power MOSFET Controller
Features and Benefits
▪
Drives wide range of N-channel MOSFETs
▪
Synchronous rectification
▪
Power MOSFET protection
▪
Adjustable dead time for cross-conduction protection
▪
100% duty cycle operation
▪
Selectable fast or slow current-decay modes
▪
Internal PWM peak current control
▪
High-current gate drive
▪
Motor lead short-to-ground protection
▪
Internal 5 V regulator
▪
Brake input
▪
PWM torque-control input
▪
Fault-diagnostic output
▪
Tachometer output
▪
Thermal shutdown
▪
Undervoltage protection
Description
The A3932 is a three-phase MOSFET controller for use with
bipolar brushless DC motors. Its high gate-current drive
capability allows driving a wide range of N-channel power
MOSFETs and can support motor supply voltages to 50 V.
Bootstrapped high-side drive blocks provide the floating
positive supplies for the gate drive and minimize the component
count normally required. The high-side circuitry also employs a
unique FET monitoring circuit that ensures the gate voltages are
at the proper levels before turn-on and during the ON cycle.
Internal fixed off-time PWM current-control circuitry can be
used to regulate the maximum load current to a desired value.
The peak load-current limit is set by the user’s selection of
an input reference voltage and external sensing resistor. The
fixed off-time pulse duration is set by a user-selected external
RC timing network. For added flexibility, the PWM input can
be used to provide speed/torque control, allowing the internal
current control circuit to set the maximum current limit.
Optional synchronous rectification is included. This feature will
short out the current path through the power MOSFET reverse
body diodes during the PWM off-cycle current decay. This can
minimize power dissipation in the power MOSFET, eliminate
the need for external power clamp diodes, and potentially allow
more economical choices for the MOSFET application.
Packages
38-pin TSSOP (suffix LD)
The A3932 includes the commutation logic for Hall sensors
configured for 120 degree spacing. Power MOSFET protection
features include bootstrap capacitor charging current monitor,
undervoltage monitor, motor-lead short-to-ground, and thermal
shutdown.
The ‘–S–’ part-number suffix indicates an operating temperature
range of -20°C to +85°C. The ‘–LD–’ suffix indicates a 38-lead
TSSOP package. The initial ‘–TR–’ variant suffix indicates
tape and reel packing. The ‘–T’ final variant suffix indicates
lead (Pb) free composition, with 100% matte tin leadframe
plating.
Not to scale
26301.101H
A3932
Three-Phase Power MOSFET Controller
ELECTRICAL CHARACTERISTICS: unless otherwise noted at T
A
= 25°C; V
BB
= 18 V to 50 V; C
LCAP
,
C
boot
= 0.1
μF;
C
REG
= 10
μF;
C
load
= 3300 pF
;
f
PWM
= 22.5 kHz Square Wave; Two Phases Active.
Limits
Parameter
Supply Current
Quiescent Current
Reference Voltage
Output Voltage
I
BB
V
LCAP
V
REG
RESET high, coast mode, stopped
I
LCAP
= -3 mA
V
BB
= V
REG
≤15
V, I
REG
= -10 mA
18 V
≤
V
BB
≤
50 V, I
REG
= -10 mA
V
BB
= 13.2 V to 18 V, I
REG
= -10 mA
Output Voltage Regulation
Digital Logic Levels
Logic Input Voltage
V
IH
V
IL
Logic Input Current
Gate Drive
Low-Side Output Voltage
High-Side Output Voltage
Pulldown Switch Resistance
Pullup Switch Resistance
Low-Side Output
Switching Time
High-Side Output
Switching Time
Propagation Delay Time
(PWM to gate output)
Maximum Dead Time
Minimum Dead Time
V
GLxH
V
GHxH
r
DS(on)
r
DS(on)
t
rGLx
t
fGLx
t
rGHx
t
fGHx
t
pr
t
pf
t
dead
t
dead
I
GLx
= 0
I
GHx
= 0
I
GLx
= 50 mA
I
GHx
= -50 mA
10% to 90%, with C
load
90% to 10%, with C
load
10% to 90%, with C
load
90% to 10%, with C
load
GHx, GLx rising, C
load
= 0
GHx, GLx falling, C
load
= 0
GHx to GLx, V
DEAD
= 0 V, C
load
= 0
GLx to GHx, I
DEAD
= 780
μA,
C
load
= 0
V
REG
- 0.8 V
REG
- 0.5
10.4
–
–
–
–
–
–
–
–
3.5
50
11.6
4.0
14
120
60
120
60
220
110
5.6
100
–
12.8
–
–
–
–
–
–
–
–
7.6
150
V
V
ns
ns
ns
ns
ns
ns
μs
ns
I
IH
I
IL
All inputs except SR
SR input only
All inputs except SR
SR input only
V
IH
= 2 V
V
IL
= 0.8 V
2.0
3.0
–
–
-30
-50
–
–
–
–
–
–
–
–
0.8
1.8
-90
-130
V
V
V
V
μA
μA
V
REG(IREG)
I
REG
= -1 to -30 mA, coast
VREG(VBB)
I
REG
= -10 mA, coast
–
4.75
10.8
12.4
–
–
–
–
5.0
–
13
V
BB
- 2.5
25
40
8.0
5.25
13.2
13.6
–
–
–
mA
V
V
V
V
mV
mV
Symbol
Conditions
Min
Typ
Max
Units
NOTES: 1. Typical Data is for design information only.
2. Negative current is defined as coming out of (sourcing) the specified device terminal.
Continued —
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
Embedded System
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