Datasheet

V
INH
(1 V/div)
V
O
(2 V/div)
I
I
(2 A/div)
t − Time − 4 ms/div
2
1
3
V
I
Inhibit
GND
PTR08060W
C
I
GND
V
I
UDG-07117
1=Inhibit
PTR08060W
SLTS289G –AUGUST 2007–REVISED MARCH 2013 www.ti.com
Output On/Off Inhibit
For applications requiring output voltage on/off control, the PTR08060W power module incorporates an output
on/off Inhibit control (pin 1). The inhibit feature can be used wherever there is a requirement for the output
voltage from the regulator to be turned off.
The power module functions normally when the Inhibit pin is left open-circuit, providing a regulated output
whenever a valid source voltage is connected to Vin with respect to GND.
Figure 13 shows the typical application of the inhibit function. Note the discrete transistor (Q1). The Inhibit control
has its own internal pullup to V
I
potential. An open-collector or open-drain device is recommended to control this
input.
Turning Q1 on applies a low voltage to the Inhibit control pin and disables the output of the module. If Q1 is then
turned off, the module will execute a soft-start power-up sequence. A regulated output voltage is produced within
20 msec. Figure 14 shows the typical rise in the output voltage, following the turn off of Q1. The turn off of Q1
corresponds to the fall in the waveform, Q1 Vgs. The waveforms were measured with a 4-A constant current
load.
Figure 13. On/Off Inhibit Control Circuit
Figure 14. Power Up Response From Inhibit Control
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