Two Complete PWM Control Circuits

Outputs Drive MOSFETs Directly

Oscillator Frequency . . . 50 kHz to 2 MHz

3.6-V to 20-V Supply-Voltage Range

Low Supply Current . . . 3.5 mA Typ

Adjustable Dead-Time Control, 0% to 100%

1.26-V Reference

description

The TL1454A is a dual-channel pulse-width-modulation

(PWM) control circuit, primarily intended

for low-power, dc/dc converters. Applications

include LCD displays, backlight inverters, notebook

computers, and other products requiring

small, high-frequency, dc/dc converters.

Each PWM channel has its own error amplifier, PWM comparator, dead-time control comparator, and MOSFET

driver. The voltage reference, oscillator, undervoltage lockout, and short-circuit protection are common to both

channels.

Channel 1 is configured to drive n-channel MOSFETs in step-up or flyback converters, and channel 2 is

configured to drive p-channel MOSFETs in step-down or inverting converters. The operating frequency is set

with an external resistor and an external capacitor, and dead time is continuously adjustable from 0 to 100%

duty cycle with a resistive divider network. Soft start can be implemented by adding a capacitor to the dead-time

control (DTC) network. The error-amplifier common-mode input range includes ground, which allows the

TL1454A to be used in ground-sensing battery chargers as well as voltage converters.