DRV103UG4 Datasheet, PDF (7/24 Pages) Burr-Brown (TI) – PWM LOW-SIDE DRIVER (1.5A and 3A) for Solenoids, Coils, Valves, Heaters, and Lamps

BASIC OPERATION
The DRV103 is a low-side, DMOS 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 low 0.5Ω “ON”
resistance, small size, 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
DRV103. A 1µF (22µF when driving high current loads) or
larger tantalum bypass capacitor is recommended on the
power-supply pin.
Input (pin 8) is level-triggered and compatible with standard
TTL levels. An input voltage between +2.2V and +5.5V
turns the device’s output ON, while a voltage of 0V to
+1.2V shuts the DRV103’s output OFF. Input bias current is
typically 1pA. Delay Adjust (pin 2) and Duty Cycle Adjust
(pin 1) allow external adjustment of the PWM output signal.
The Delay Adjust pin can be left floating for minimum delay
to PWM mode (typically 18µs) or a capacitor can be used to
set a longer delay time. A resistor, analog voltage, or a
voltage from a D/A converter can be used to control the duty
cycle of the PWM output. The D/A converter must be able
to sink a current 2.75 • I_REF (I_REF = 1.3V/R_FREQ).
Figure 2 illustrates a typical timing diagram with the Delay
Adjust pin connected to a 3.9nF capacitor, the duty cycle set
to 75%, and oscillator frequency set to 1kHz. See the “Delay
Adjust” and “Duty Cycle Adjust” text for equations and
further explanation. Ground (pin 4) must be connected to
system ground for the DRV103 to function. This serves as
the load current path to ground, as well as the DRV103
signal ground. The load (relay, solenoid, valve, etc.) should
be connected between the supply (pin 5) and output (pin 6).
For an inductive load, an external “flyback” diode is re-
quired, as shown in Figure 1. The diode serves to maintain
continuous current flow in the inductive load during OFF
periods of PWM operation. For remotely located loads, the
external diode is ideally located next to the DRV103. The
internal ESD clamp diode between the output and supply is
not intended to be used as a “flyback diode.” The Status OK
Flag (pin 7) provides fault status for over-current and
thermal shutdown conditions. This pin is active LOW with
output voltage of typically +0.3V during a fault condition.
2mA
R_LED
+V_S
+8V to +32V
LED
OK = LED “on”
7
1µF
+
6
3A
Flyback
Diode⁽¹⁾
Relay
TTL IN
Status
+V_S
OK
5
8
DRV103
OUT
NOTE: (1) Motorola MSRS1100T3 (1A, 100V)
Delay
Adj
2
Osc Freq
Adj
3
Duty Cycle
Adj
1
GND
4
Motorola MBRS360T3 (3A, 60V)
or
Microsemi SK34MS (3A, 40V)
C_D
R_FREQ
R_PWM
FIGURE 1. DRV103 Basic Circuit Connections.
ON
TTL HIGH
Input (V)
TTL LOW ^OFF
+V_S
V_O (V)
0
Delay Time
Period =
1
FREQ
= T_ON + T_OFF
OFF
+V_S/R_L
I_O (A)
0
Duty Cycle =
T_ON
T_ON + T_OFF
T_OFF
T_ON
0
1
2
3
4
5
6
7
8
Time (ms)
FIGURE 2. Typical DRV103 Timing Diagram, with C_D = 3.9nF, OscFreq = 1kHz, and 75% Duty Cycle.
DRV103
SBVS029A
9
7