UC3842A Ver la hoja de datos (PDF) - First Components International

Número de pieza

componentes Descripción

Fabricante

UC3842A

Current Mode PWM Controller

First Components International 

UC384XA-BW Current Mode PWM Controller

(UC3842A-BW/ 43A-BW/ 44A-BW/ 45A-BW)

PIN FUNCTION

N FUNCTION

1 COMP

2 VFB

3 ISENSE

4 RT/CT

5 GROUND

6 OUTPUT

7 VCC

8 Vref

DESCRIPTION

This pin is the Error Amplifier output and is made for loop compensation.

This is the inverting input of the Error Amplifier. It is normally connected to the

switching power supply output through a resistor divider.

A voltage proportional to inductor current is connected to this input. The PWM

uses this information to terminate the output switch conduction.

The oscillator frequency and maximum Output duty cycle are programmed by

connecting resistor RT to Vref and capacitor CT to ground.

This pin is the combined control circuitry and power ground.

This output directly drives the gate of a power MOSFET. Peak currents up to 1A

are sourced and sink by this pin.

This pin is the positive supply of the integrated circuit.

This is the reference output. It provides charging current for capacitor CT through

resistor RT .

APPLICATION INFORMATION

Figure 1. Error Amp Configuration

Figure 2. Undervoltage Lockout

3

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