Electronic Devices And Components

The TL494 TL494CN is a PWM Control Circuit that incorporates all the functions required in the construction of a pulse-width-modulation (PWM) control circuit on a single chip. Designed primarily for power-supply control, this device offers the flexibility to tailor the power-supply control circuitry to a specific application. The error amplifiers exhibit a common-mode voltage range. The dead-time control comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed by terminating RT to the reference output and providing a sawtooth input to CT or it can drive the common circuits in synchronous multiple-rail power supplies.

The UC3843 IC is a current Mode PWM Controller, meaning it can be used to provide a constant current by varying the output voltage to the load. While building Switch mode supplies with feedback there are two modes of control that are commonly used, one is voltage mode control where the output voltage will keep constant irrespective of the current (CV mode) and the other is current mode control where the output current will be constant (C mode) irrespective of the voltage. The UC3843 can be used to regulate or limit current in applications like SMPS, RPS, DC-DC Converters, Line voltage regulators, etc.