PWM controller for multi-topology power supplies
The Texas Instruments TL494CNSRG4 is a fixed-frequency PWM controller supporting buck, boost, flyback, forward converter, full-bridge, half-bridge, and push-pull topologies. It operates from a 7V to 40V supply rail and switches from 1kHz up to 300kHz, giving the designer flexibility to balance transformer size against switching losses. Two transistor-driver outputs deliver a maximum duty cycle of 45% per output, which is the standard limit for push-pull and half-bridge stages where dead time between phases prevents shoot-through.
With a 45% duty cycle ceiling per output, the TL494CNSRG4 is inherently suited for push-pull and half-bridge converters where each output drives one primary winding half. The dead time control pin lets the designer insert programmable gaps between the two output pulses, which is essential for transformer reset in forward converters and for avoiding cross-conduction in bridge stages. The 1kHz to 300kHz switching range covers both line-frequency transformer-coupled designs and higher-density planar magnetics. At 300kHz the transformer shrinks, but the gate-drive losses and core losses rise — the trade-off is design-specific.
Commercial temperature grade and package
The 16-SOIC package (0.209-inch body width, 5.30mm height) is a standard surface-mount footprint that reflows on a standard profile. The supply voltage range from 7V to 40V covers most unregulated DC buses from 12V to 36V nominal, including the 24V industrial rail and the 36V telecom bus. The undervoltage lockout threshold is internal; below 7V the outputs are disabled.
The TL494CNSRG4 is the tape-and-reel variant of the industry-standard TL494CN, sharing the same die and pinout.