PWM controller for isolated and non-isolated supplies
The Texas Instruments TL494IDG4 is a fixed-frequency PWM controller that supports step-up, step-down, and step-up/step-down topologies including buck, boost, flyback, forward converter, full-bridge, half-bridge, and push-pull configurations. It delivers two transistor-driver outputs with a maximum duty cycle of 45% per output, suitable for push-pull and half-bridge designs where transformer reset timing matters. The switching frequency spans 1kHz to 300kHz, letting the designer trade off transformer size against core losses.
Operating from a 7V to 40V supply, the controller can run directly off an unregulated bulk rail without a separate pre-regulator, simplifying the front-end bill of materials.
Control features and package
On-chip dead-time control and frequency control allow the designer to set the overlap blanking and oscillator timing with external resistors and capacitors.