UC3843B

Pin Number

Pin Name

Description

1

COMP (Comparator)

It is an output pin which outputs low impedance 1MHz single based in the difference between he set and current voltage. It is normally connected to the voltage feedback pin of the IC through resistor and capacitor.

2

VFB (Voltage Feedback)

It is an input to the error amplifier that inside the IC. The difference in voltage level is supplied to this pin

3

Current Sense

A shunt resistor is used to monitor the current through the circuit and the voltage across it is provided as a feedback to the current sense pin

4

RT/CT (Timing Resistor/ Timing Capacitor)

The IC has an internal oscillator which can be set using an external Resistor and capacitor connected to this pin.

5

Ground

Connected to the ground of the circuit

6

Output

This pin outputs the PWM signal based on the feedback provided and we can use this to switch the power electronic device.

7

Vcc

Supply voltage for the IC (Nominal 11V)

8

VREF

Reference voltage based on which the PWM signal is produced.