The TL1454 is a dual-channel pulse-width-modulation (PWM) control circuit, primarily intended for low-power dc-dc converters. The TL1454 is optimized for systems requiring both boost and buck converters: Channel 1 is configured to drive n-channel MOSFETs in step-up or flyback converters. Channel 2 is configured to drive p-channel MOSFETS in step-down or inverting converters.
Each PWM channel has its own error amplifier, PWM comparator, dead-time control comparator, and MOSFET driver. The TL1454 includes an integrated voltage reference, oscillator, undervoltage lockout, and short-circuit protection common to both channels.
The TL1454's operating frequency is set from 50 kHz to 2 MHz using an external resistor and capacitor. The high-frequency operation allows the use of smaller external components to produce a higher efficiency converter. Dead-time duty cycle is adjustable from 0 to 100% using a resistive divider; soft start can be implemented by adding a capacitor to the dead-time control network.
The error amplifiers' common-mode input voltage range includes ground, which allows the TL1454 to be used in ground-sensing battery chargers as well as voltage converters.
Applications for the TL1454 include LCD displays, backlight inverters, notebook computers, and other products requiring small, high-frequency dc-dc converters.
The TL1454 is offered in 16-pin DIP, SOIC, and TSSOP packages, in commercial (0ºC to 70ºC) and industrial (-40ºC to 85ºC) temperature grades.
Vol 14, December, 1995
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