TL494 Variable Switch Mode Power Supply 0-35V 0-20Amps Complete Circuit Explained

Circuit

TL494 Complete SMPS Circuit 750Watts 0-35V 0-20A Circuit

Hi. In today's video I'll show you how to make a variable and regulated Switch Mode Power Supply based on the TL494 PWM IC. The output can be smoothly adjusted from about 2 to 35Volts while the current can be set from 3 to 20 Amperes with ease. Its built on a Half-Bridge Topology, and the feasible power is 750Watt. Watch me on YouTube at ElectroBUFF.

Video Tutorial

TL494 Current-Mode PWM Controller IC Explained: Pinout, Equivalent, Sample Circuits, Applications, Features 

TL494 PWM IC Pinout DIP Package electrobuff.blogspot.com

 

TL494 Current-Mode PWM Controller
TL494 Pinout

The TL494 IC is a fixed frequency current-mode PWM controller IC with all the functions that are required in the construction of the pulse-width modulation (PWM) control circuit on a single chip.

 

TL3843 Pinout Configuration

Pin Number	Pin Name	Description
1	1IN+	Noninverting input to error amplifier 1
2	1IN-	Inverting input to error amplifier 1
3	FEEDBACK	Input pin for feedback
4	DTC	Dead-time control comparator input
5	CT	Capacitor terminal used to set the oscillator frequency
6	RT	Resistor terminal used to set the oscillator frequency
7	GND	Ground Pin
8	C1	The collector terminal of BJT output 1
9	E1	The emitter terminal of BJT output 1
10	E2	The emitter terminal of BJT output 2
11	C2	The collector terminal of BJT output 2
12	VCC	Positive Supply
13	OUTPUT CTRL	Selects single-ended/parallel output or push-pull operation
14	REF	The 5-V reference regulator output
15	2IN-	Inverting input to error amplifier 2
16	2IN+	Noninverting input to error amplifier 2

TL494 Specifications & Features

• Supply Voltage: 7V to 40V
• Number of Outputs: 2 Output
• Switching Frequency: 300 kHz
• Duty Cycle - Max: 45 %
• Output Voltage: 40 V
• Output Current: 200 mA
• Fall Time: 40 ns
• Rise Time: 100 ns
• Available in 16-pin PDIP, TSSOP, SOIC and SOP Packages

 

Equivalent/Substitute for TL494: UC3843, TL3842

Alternatives PWM controller IC:  UC2842, SG2524

 

Where to use the TL494 PWM Controller IC

The TL494 fixed frequency PWM Controller can be used for DC to DC conversion regardless of buck or boost topology. TL494 can be used to provide a constant current by varying the output voltage to the load. This IC feature an output control circuit, a flip flop, a dead time comparator, two different error amplifiers, a 5V reference voltage, an oscillator, and a PWM comparator.

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 TL494 IC

A test circuit from the TL494 datasheet is shown below.

TL494 PWM IC Circuit Application and Pinout electrobuff.blogspot.com

Non inverting pins are connected to the Ref pin while inverting pins are connected to the ground. Test inputs are given to DTC and FEEDBACK pins. External capacitor and resistor are connected to pin 5 & 6 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

 

Applications of TL494

• 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 TL494

Dimensions for TL3494 IC is given below. These dimensions are for the PDSO package. If you are using a different package IC, please refer to the TL494 datasheet.

TL494-Dimensions 2D PCB Footprint  electrobuff.blogspot.com

youtube.com/@ELECTROBUFF