Datasheet

R1
30 k:
15.4 k:
2 k:
1 k:
NDP606A
Set
Clear
R2
82 k:
Supply > 7.0V
1 PF
0.1 PF
1234
8765
N.O.
N.O.
8A
Load
LM9061
SNOS738F –APRIL 1995–REVISED APRIL 1995 www.ti.com
REVERSE BATTERY
The LM9061 is not protected against reverse polarity supply connections. If the V
CC
supply should be taken
negative with respect to ground, the current from the V
CC
pin should be limited to 20 mA. The addition of a diode
in series with the V
CC
input is recommended. This diode drop does not subtract significantly from the charge
pump gate overdrive output voltage.
LOW BATTERY
An additional feature the LM9061 is an Under-Voltage Shut-OFF function (UVSO). The typical UVSO threshold is
6.2V, and does not have hysteresis. When V
CC
is between the ensured minimum operating voltage of 7.0V, and
the UVSO threshold, the operation of the MOSFET gate drive, the delay timer, and the protection circuitry is not
ensured. Operation in this region should be avoided. When V
CC
falls below the UVSO threshold the charge pump
will be disabled and the gate will be discharged at the Normal-OFF current sink rate, typically 110 μA.
Figure 20 shows the LM9061 used as an electronic circuit breaker. This circuit provides low voltage shutdown,
over-voltage latch-OFF, and over-current latch-OFF.
The low voltage shutdown uses the 'On' and 'Off' voltage thresholds, and the typical 1.2V of hysteresis, to
disable the LM9061 if V
CC
falls near, or below, the 7.0V minimum operating voltage. The low voltage shutdown is
accomplished with a voltage divider biased off V
CC
. The voltage divider is formed by R1 (30 kΩ), R2 (82 kΩ), and
the internal pull-down resistor of the ON/OFF pin (30 kΩ typical). In normal operation, V
CC
will be above the
minimum operating voltage of 7.0V, and the On/Off pin will be biased above the 'Off' threshold of 1.5V maximum
(1.8V typical). When V
CC
falls to 7.0V the On/Off pin voltage will fall below the 'Off' threshold voltage and the
LM9061 will be turned off.
In the event of a latch-OFF shutdown, the circuit can be reset by shutting the main supply off, then back on. An
optional, normally open, switch (Clear) from the ON/OFF pin to ground, will allow a “push button clear” of the
circuit after latching OFF.
Figure 20. Electronic Circuit Breaker
16 Submit Documentation Feedback Copyright © 1995, Texas Instruments Incorporated
Product Folder Links: LM9061