DRV101_15 Datasheet, PDF (8/27 Pages) Texas Instruments – PWM SOLENOID/VALVE DRIVER

BASIC OPERATION
The DRV101 is a low-side, bipolar power switch employing
a pulse-width modulated (PWM) output for driving electro-
mechanical and thermal devices. Its design is optimized for
two types of applications; a two-state driver (open/close) for
loads such as solenoids and actuators, and a linear driver for
valves, positioners, heaters, and lamps. Its wide supply
range, adjustable delay to PWM mode, and adjustable duty
cycle make it suitable for a wide range of applications.
Figure 1 shows the basic circuit connections to operate the
DRV101. A 0.1µF bypass capacitor is shown connected to
the power supply pin.
The Input (pin 1) is compatible with standard TTL levels.
Input voltages between +2.2V and +5.5V turn the device
output on, while pulling the pin low (0V to +1.2V), shuts the
DRV101 output off. Input current is typically 80µA.
Delay Adjust (pin 2) and Duty Cycle Adjust (pin 3) allow
external adjustment of the PWM output signal. The Delay
Adjust pin can be left floating for minimum delay to PWM
mode (typically 15µs) or a capacitor can be used to set the
delay time. Duty cycle of the PWM output can be controlled
by a resistor, analog voltage, or D/A converter. Figure 1b
provides an example timing diagram with the Delay Adjust
pin connected to 0.1µF and duty cycle set for 25%. See the
“Delay Adjust” and “Duty Cycle Adjust” text for equations
and further explanation.
Ground (pin 4) is electrically connected to the package tab.
This pin must be connected to system ground for the
DRV101 to function. This serves as the load current path to
ground, as well as the DRV101 reference ground.
The load (solenoid, valve, etc.) is connected between the
supply (pin 5) and output (pin 6). For an inductive load, an
external diode across the output is required as shown in
Figure 1a. The diode serves to maintain the hold force during
PWM operation. For remotely located loads, the external
diode should be placed close to the DRV101 (Figure 1a). The
internal clamp diode between the output and ground should
not be used to carry load current.
The Flag (pin 7) provides fault status for under-current,
over-current, and thermal shutdown conditions. This pin is
active low with pin voltage typically +0.3V during a fault
condition. A small value capacitor may be needed between
Flag and ground for noisy applications.
Basic Circuit Connections
Flag
V_S
0.1µF
7
5
Thermal Shutdown
Over/Under Current
(a)
Input
1
(TTL-Compatible)
On
Off
Delay
2
24kHz
Oscillator
PWM
3
C_D
Delay
Adjust
R_PWM ^{Duty Cycle Adjust}
(1)
6
Out
Gnd
4
(electrically
connected to
tab)
Load
NOTE: (1) External flyback diode required for inductive loads to conduct load current during the off cycle.
For remotely located loads, diode should be placed close to the DRV101.
Motorola MSRS1100T3 (1A, 100V), MBRS360T3 (3A, 60V)
Simplified Timing Diagram
C_D = 0.1µF (95ms constant dc output before PWM)
R_PWM = 130kΩ
+2.2V to +5.5V
INPUT
0V to +1.2V
(b)
V_S
OUTPUT
0
•••
C_D = 0.1µF
95ms
t_ON
t_P
Initial dc Output
(set by value
of C_D)
PWM Mode
(resistor or voltage
controlled)
•••
R_PWM = 130kΩ
t_ON ≈ 10.4µs
t_P ≈ 41.6µs (1/24kHz)
Duty Cycle = ^tON = 25%
t_P
FIGURE 1. Basic Circuit Connections and Timing Diagram.
8
DRV101
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