PULSE-WIDTH.MOD CONTROL

Description

The TL494 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 TL494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits.

The error amplifiers exhibit a common-mode voltage range from –0.3 V to V_CC–2 V. 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.

Features

• 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 With 5% Tolerance
• Circuit Architecture Allows Easy Synchronization