TL494 Dual Rail Power Supply Circuit for Amplifier 500W 12V to +40V-0-40Volts
TL494 Dual Rail Power Supply Circuit for Amplifier 500W 12V to +40V-0-40Volts
TL494 Dual Rail Power Supply Circuit Diagram
TL494 Dual Rail Power Supply Circuit for Amplifier 500W 12V to +40V-0-40Volts electrobuff.blogspot.com
The circuit is fairly straightforward: The TL494 PWM Controller IC generates alternating signals at a frequency of about 45kHz which are used to switch two power MOSFETs configured in a push-pull topology. The Mosfets in turn switch the DC power supply back and forth across the primary windings of the Ferrite power transformer (note the primary winding has a center tap).
high frequency ferrite pulse transformer electrobuff.blogspot.com
The transformer steps up the voltage depending on the windings turns ration between the primary and secondary and the input DC voltage from the power supply. At the secondary you get a high frequency alternating current which is filtered and rectified, then smoothened to obtain low ripple Direct Current with dual output voltage for powering an audio power amplifier.
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TL494 Current-Mode PWM Controller IC Explained: Pinout, Equivalent, Sample Circuits, Applications, Features
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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.
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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.
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| TL494-Dimensions 2D PCB Footprint electrobuff.blogspot.com |
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