HTC KOREA TL494 Pulse Width Modulation Control Controller

- Complete PWM Power Control Circuitry

- Uncommitted Outputs for 200 Ma Sink or Source Current

- Output Control Selects Single-Ended or Push-Pull Operation

- Internal Circuitry Prohibits Double Pulse at Either Output

- Variable Dead-Time Provides Control over Total Range

- Internal Regulator Provides a Stable 5-V Reference Supply,5%

- Circuit Architecture Allows Easy Synchronization

- Moisture Sensitivity Level 3

 

DESCRIPTION

The TL494 incorporate on a single monolithic chip all the functions required in the construction of a pulse-width-modulation control, these devices offer the systems engineer the flexibility to tailor the power supply control circuitry to his application.

The TL494 contains an error amplifier, an on-chip adjustable oscillator, a dead-time control comparator, pulse-steering control flip-flop, a 5-volt, 5% precision regulator, and output-control circuit.

The error amplifier exhibits a common-mode voltage range from -0.3 volts to Vcc -2 volts. The dead-time control comparator has a fixed offset that provides approximately 5% dead time when externally altered. The on-chip oscillator may be bypassed by terminating R T (pin 6) to the reference output and providing a sawtooth in put to CT (pin 5), or it may be used to drive the common circuits in synchronous multiple-rail power supplies. The uncommited output transistors provide either common-emitter or emitter-follower output capability. Each Device provides for push-pull or single-ended output operation, which may be selected through the output-control funct -ion. The architecture of these devices prohibits the possibility of either output being pulsed twice during push -pull operation.