DRV102_15 Datasheet, PDF (8/27 Pages) Texas Instruments – PWM SOLENOID/VALVE DRIVER

BASIC OPERATION
The DRV102 is a high-side, bipolar power switch employ-
ing a pulse-width modulated (PWM) output for driving
electromechanical and thermal devices. Its design is opti-
mized 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 DRV102. 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
DRV102 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
DRV102 to function. This serves as the DRV102 reference
ground.
The load (solenoid, valve, etc.) is connected between the
output (pin 6) and ground. For an inductive load, an external
flyback diode (D₁ in Figure 1a) across the output is required.
The diode serves to maintain the hold force during PWM
operation. Depending on the application, the flyback diode
should be placed near the DRV102 or close to the solenoid
(see “Flyback Diode” text). The device’s internal clamp
diode, connected between the output and ground, should not
be used to carry load current. When driving inductive loads,
an additional diode in series with the out pin, D₂, is required
(see “Series Diode” text).
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 +0.2V during a fault
condition. A small value capacitor may be needed between
Flag and ground for noisy applications.
1a). Basic Circuit Connections
Flag
On
Off
1
Input
(TTL-Compatible)
7
Thermal Shutdown
Over/Under Current
24kHz
Oscillator
DRV102
V_S
(+8V to +60V)
0.1µF
5
V_S
Delay
2
C_D
Delay
Adjust
PWM
6
D₂
Out
R_PWM
3
Gnd 4 _{(Gnd electrically}
Duty
connected to tab)
Cycle
Adjust
D₁ ⁽¹⁾
Load
NOTE: (1) External flyback diode required for inductive loads to conduct load current during the off cycle.
Flyback diode shown near DRV102. For some applications with remotely located load, it may be desirable
to place the diode near the solenoid—see “Flyback Diode” text. Motorola MSRS1100T3 (1A, 100V) or
MBRS360T3 (3A, 60V).
1b). Simplified Timing Diagram
C_D = 0.1µF (92ms constant dc output before PWM)
R_PWM = 90.9kΩ
+2.2V to +5.5V
•••
INPUT
0V to +1.2V
OUTPUT
V_S
C_D = 0.1µF
0
92ms
•••
t_ON
R_PWM = 90.9kΩ
t_P
Initial dc Output PWM Mode
t_ON ≈ 10.4µs
t_P ≈ 41.6µs (1/24kHz)
Duty
Cycle
=
t_ON
t_P
= 25%
(set by value (resistor or voltage
of C_D)
controlled)
FIGURE 1. Basic Circuit Connections and Timing Diagram.
8
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DRV102
SBVS009B