Datasheet

DRV104
7
SBVS036B
www.ti.com
FIGURE 1. DRV104 Basic Circuit Connections.
BASIC OPERATION
The DRV104 is a high-side, DMOS power switch employing
a PWM output for driving electromechanical and thermal
devices. Its design is optimized for two types of applications:
as a 2-state driver (open/close) for loads such as solenoids
and actuators; and a linear driver for valves, positioners,
heaters, and lamps. Its low 0.45Ω 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
DRV104. A 1µF (10µF when driving high current loads) or
larger ceramic bypass capacitor is recommended on the
power-supply pin.
Control input (pin 14) 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 DRV104’s output Off. Input bias current is
typically 1µA. 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 of 2.75 • I
REF
(I
REF
= V
REF
/R
FREQ
).
Figure 2 illustrates a typical timing diagram with the Delay
Adjust pin connected to a 4.7nF capacitor, the duty cycle set
to 75%, and oscillator frequency set to 1kHz. See the
Adjustable and Adjustable Delay Time section for equations
and further explanation. Ground (pin 11) must be connected
to the system ground for the DRV104 to function. The load
(relay, solenoid, valve, etc.) should be connected between
the ground and the output (pins 6, 7). For an inductive load,
an external flyback diode is required, as shown in Figure 1.
The diode maintains 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
DRV104. The internal ESD clamp diode between the output
and ground is not intended to be used as a “flyback diode.”
The Status OK Flag (pin 13) provides fault status for over-
current and thermal shutdown conditions. This pin is active
Low with an output voltage of typically +0.48V during a fault
condition.
Delay
Adj
C
D
R
PWM
TTL IN
Relay
C
BOOT
(2)
+V
S
GND
OUT
+V
S
Status
OK Flag
3A
Flyback
Diode
(1)
+8V to +32V
Osc Freq
Adj
Duty Cycle
Adj
R
FREQ
(3)
DRV104
11 5132
14
6, 7
1013
V
PS
8, 9
R
LED
LED
OK = LED On
2mA
1µF
+
NOTES: (1) Motorola MSRS1100T3 (1A, 100V),
Motorola MBRS360T3 (3A, 60V), or Microsemi SK34MS (3A, 40V).
(2) Performance specified with C
BOOT
= 470pF. (3) When switching a
high-load current, a 100pF capacitor in parallel with R
FREQ
is
recommended to maintain a clean output switching waveform
and duty cycle, see Figure 5.
T
OFF
T
ON
On
Off
Off
Period =
= T
ON
+ T
OFF
1
FREQ
Duty Cycle =
T
ON
T
ON
+ T
OFF
Delay Time
+V
S
V
O
(V)
0
+V
S
/R
L
I
O
(A)
0
TTL High
Input (V)
TTL Low
0 1 2 3 4
Time (ms)
5 6 7 8 9
FIGURE 2. Typical Timing Diagram.