TL494

脉冲宽度调制 Pwm 控制电路

The device 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 device 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 VCC – 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.

The uncommitted output transistors provide either common-emitter or emitter-follower output capability. The TL494 device provides for push-pull or single-ended output operation, which can be selected through the output-control function. The architecture of this device prohibits the possibility of either output being pulsed twice during push-pull operation.

The TL494C device is characterized for operation from 0°C to 70°C. The TL494I device is characterized for operation from –40°C to 85°C.

.

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