udn2962 Allegro MicroSystems, Inc., udn2962 Datasheet - Page 4

• Manufacturer Part Number: udn2962
• Description: Dual Solenoid/motor Driver .pulse-width Modulated Current Control
• Manufacturer: Allegro MicroSystems, Inc.

free-running, pulse-width modulated solenoid driver.
both turned on by a low level at the input. The load current rises with
time as a function of the load inductance, total circuit resistance, and
supply voltage and is sensed by the external sense resistor (R
When the load current reaches the trip point (I
output goes high and turns off the source driver. The actual load
current will peak slightly higher than I
and switching delays.
circulate through the sink driver and an internal ground clamp diode.
The rate of current decay is a function of the load inductance and total
circuit resistance.
until the decaying load current reaches the lower threshold, when the
comparator output goes low and the source driver is again turned on.
Load current is again allowed to rise to the trip point and the cycle
repeats.
current (I
threshold voltage, V
independent of the load current:
system and circuit parameters, including load inductance, supply
voltage, hysteresis setting, and switching speed of the driver.
2962
DUAL PWM
SOLENOID/MOTOR DRIVER
Circuit Description. In operation, the source and sink drivers are
After the source driver is turned off, the load current continues to
Maximum load current and hysteresis is determined by the user.
Determining Maximum Load Current and Hysteresis. Trip
where V
Hysteresis percentage (H) is determined by resistance R
The chopping frequency is asynchronous and a function of the
Resistance R
Note that if V
An internal constant current sink reduces the trip point (hysteresis)
The UDN2962W high-current driver is intended for use as a
TRIP
THS
) is determined as a function of resistance R
= 10 x V
THS
T
is determined as:
THS
= V
R
:
I
TRIP
H =
T
REF,
SENSE
=
V
50 x V
then R
=
REF
R
= 0.6 V to 5.0 V.
H
10 R
R
V
V
– V
THS
H
THS
REF
T
S
=
THS
TRIP
∞.
because of the internal logic
TRIP
), the comparator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
S
and the
H
S
and is
).
V IN
V SOURCE
I
V
V THS
LOAD
SINK
between channels, each of the two high-level
power ground returns (the low side of the
sense resistors) must be returned independ-
ently to the low-level signal ground (pin 1).
The circuit common (pin 1) can then be
routed to the system ground.
heavy ground plane. For optimum perform-
ance, the driver should be soldered directly
into the board.
decoupled with an electrolytic capacitor
(≥10 µF) as close as possible to pin 7.
Circuit Layout. To prevent interaction
The printed wiring board should utilize a
The power supply (V
1
3
R
S
R
S
CC
SUPPLY
7
) should be
+
GND
V CC
GND
I TRIP
V
CC
10
Dwg. WP-006
•
Dwg. OP-001
R
S
=
V
THS
10