Dual-Channel Pulse-Width-Modulation (PWM) Control Circuit

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.