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SG3524 Regulating Pulse Width Modulator IC

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The SG3524 IC incorporates all the functions required in the construction of a regulating power supply, inverter, or switching regulator on a single chip. SG3524 also can be used as the control element for high-power-output applications.

 

SG3524 Pinout Configuration

Pin Number

Pin Name

Description

1

1IN-

Inverting input to error amplifier 1

2

1IN+

Non-Inverting input to error amplifier 1

3

OSC OUT

Oscillator Output

4

CURR LIM+

Positive current limiting amplifier input

5

CURR LIM-

Negative current limiting amplifier input

6

RT

Resistor terminal used to set the oscillator frequency

7

CT

Capacitor terminal used to set the oscillator frequency

8

GND

Ground Pin

9

COMP

Error amplifier compensation pin

10

SHUTDOWN

Device shutdown

11

EMIT 1

Emitter terminal of BJT output 1

12

COL 1

Collector terminal of BJT output 1

13

COL 2

Collector terminal of BJT output 2

14

EMIT 2

Emitter terminal of BJT output 2

15

VCC

Positive supply

16

REF OUT

Reference regulator output

 

SG3524 Specifications & Features

  • Supply Voltage: 8V to 40V
  • Output Voltage: 4.6 V to 5.4 V
  • Output Current: 50 mA
  • Number of Outputs: 2 Output
  • Topology: Boost, Buck, Fly-back, Forward, Push-Pull
  • Switching Frequency: 722 kHz
  • Duty Cycle - Max: 45 %
  • Fall Time: 100 ns
  • Rise Time: 200 ns
  • Available in 16-pin PDIP, PDSO, and SOIC Packages

 

Note: Complete Technical Details can be found at the SG3524 datasheet given at the end of this page.

 

Equivalent/Substitute for SG3524: UC3843, TL3842, TL494

Alternatives PWM controller IC:  UC2842, SG2524

 

Where to use the SG3524 PWM Controller IC

The SG3524 Regulating Pulse Width Modulator can be used for DC to DC conversion regardless of buck or boost topology. The SG3524 were designed for switching regulators of either polarity, transformer-coupled dc-to-dc converters, transformerless voltage doublers, and polarity-converter applications employing fixed-frequency, pulse-width modulation (PWM) techniques.

 

So if you are looking for an IC to produce PWM signals for controlling a power switch based on the current flowing through the circuit, then this IC might be the right choice for you.

 

How to use SG3524

Although the IC performs a sophisticated job, using it in a circuit is fairly simple and can be done with a minimum number of external components. A test circuit from the SG3524 datasheet is shown below.

SG3524 Application Circuit 

This IC has a wide operating voltage between 8V to 40V. The regulator operates at a fixed frequency that is programmed by a one-timing resistor, RT, and one timing capacitor, CT. As you can see Noninverting pin is connected to the Ref pin while inverting pins are connected to the COMP pin. External capacitor and resistor are connected to pin RT & CT to control the oscillator frequency. The error amplifier compares a sample of the 5-V output to the reference and adjusts the PWM to maintain a constant output current. The internal reference voltage is divided externally by a resistor ladder network and the output is sensed by a second resistor divider network.

 

Applications of SG3524

  • Desktop PCs
  • Microwave Ovens
  • Server PSUs
  • Solar Micro-Inverters
  • Washing Machines: Low-End and High-End
  • E-Bikes
  • Power: Telecom/Server AC/DC Supplies:
  • Smoke Detectors
  • Solar Power Inverters

 

2D-Model of SG3524

Dimensions for the SG3524 IC is given below. These dimensions are for the PDSO package. If you are using a different package IC, please refer to the SG3524 datasheet.

SG3524 Dimensions

Component Datasheet

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