PIN FUNCTIONS
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°
1
Name
Function
CROWBAR INPUT
Voltage Sense Input for Crowbar Overvoltage Protection. Normally connected to the
feedback input thus triggering the SCR when V
exceeds nominal by 20 %. May
also monitor the input and a voltage divider can be added to increase the threshold.
Connected to ground when SCR not used.
Regulator Output
Unrergulated Voltage Input. An internal Regulator Powers the L296s Internal Logic.
A resistor connected between this terminal and ground sets the current limiter
threshold. If this terminal is left unconnected the threshold is internally set (see
electrical characteristics).
Soft Start Time Constant. A capacitor is connected between this terminal and ground
to define the soft start time constant. This capacitor also determines the average
short circuit output current.
TTL – Level Remote Inhibit. A logic high level on this input disables the device.
Multiple L296s are synchronized by connecting the pin 7 inputs together and omitting
the oscillator RC network on all but one device.
Common Ground Terminal
A series RC network connected between this terminal and ground determines the
regulation loop gain characteristics.
The Feedback Terminal on the Regulation Loop. The output is connected directly to
this terminal for 5.1V operation ; it is connected via a divider for higher voltages.
A parallel RC networki connected to this terminal determines the switching frequency.
This pin must be connected to pin 7 input when the internal oscillator is used.
Input of the Reset Circuit. The threshold is roughly 5 V. It may be connected to the
feedback point or via a divider to the input.
A capacitor connected between this terminal and ground determines the reset signal
delay time.
Open collector reset signal output. This output is high when the supply is safe.
SCR gate drive output of the crowbar circuit.
2
3
4
OUTPUT
SUPPLY VOLTAGE
CURRENT LIMIT
5
SOFT START
6
7
INHIBIT INPUT
SYNC INPUT
8
9
GROUND
FREQUENCY
COMPENSATION
FEEDBACK INPUT
10
11
OSCILLATOR
12
RESET INPUT
13
RESET DELAY
14
15
RESET OUTPUT
CROWBAR OUTPUT
BLOCK DIAGRAM
L296 - L296P
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