The TL1454/TL1454Y are dual-channel pulse-width-modulation (PWM) control circuits, 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, therefore this circuit can be used in low-voltage applications.
The TL1454 and TL1454Y are dual-channel pulse-width-modulation (PWM) control circuits primarily intended for low-power DC/DC converters. Each channel includes its own error amplifier, PWM comparator, dead-time control comparator, and MOSFET driver, while sharing a common voltage reference, oscillator, undervoltage lockout, and short-circuit protection.
| Supply Voltage Range | 3.6 V to 20 V |
|---|---|
| Supply Current | 3.5 mA Typ |
| Reference Voltage | 1.25 V |
| Oscillator Frequency Range | 50 kHz to 2 MHz |
| Dead-Time Control Range | 0% to 100% |
| Undervoltage Lockout Threshold | approximately 2.9 V |
| Short-Circuit Protection Latch Reset | 2 V or less |
The frequency is set between 50 kHz and 2 MHz using an external resistor connected between RT and GND and a capacitor between CT and GND.
The SCP function prevents damage to power switches when the converter output is shorted to ground by turning off the output drives and resetting the soft-start circuit.