TL494 Pulse Width Modulation Controller IC

TL494 designed as a PWM controller IC used for power electronics circuits. This controller IC consists of on-chip two error amplifiers an oscillator with adjustable frequency feature, an output flip-flop having pulse steering control, and an output control circuit with feedback.  The error amplifiers in the IC used to compensate voltage from –0.3 to VCC – 2 volts in common voltage configuration. Whereas the comparator controls the dead-time with a fixed offset almost at a range of 5%.

The external oscillator also provides a reference frequency signal to this PWM IC. By connecting RT to the reference output pin, users can bypass an on-chip oscillator. Moreover, this controller IC used in single-end operations as well as in push-pull configuration. It also has configurable dead time, allowing for a wide range of PWM. The TL494 Pulse Width Modulation Controller IC has all of the capabilities necessary for designing a power supply circuit. It is characterised as a variable PWM IC with a fixed frequency.

This controller IC operates without the use of any external components. Only a few resistors and capacitors are required for an oscillator. According to the timing capacitor CT, this oscillator in the IC is responsible for creating a sawtooth waveform. The output signals of the TL494 IC are generated by comparing a sawtooth waveform with two error amplifier control signals. When the sawtooth voltage is larger than the voltage at the error amplifier outputs, the output signal will be turned on.

• Output signal low: if sawtooth voltage less than the control signal voltage
• Output signal High: if sawtooth voltage greater than the control signal voltage