NCV494: PWM Controller (Automotive)

The TL494 PWM Controller 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 PWM Controller 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. This PWM Controller 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 PWM Controller is characterized for operation from 0C to 70C. The TL494I is characterized for operation from -40C to 85C. The TL494B is characterized for operation from -40C to 125C. The NCV494B is characterized for -40C to 125C and certified for automotive applications.