7.3.1 PWM Operation

The main control loop of the TPS53014 is an adaptive on-time pulse width modulation (PWM) controller that supports a proprietary D-CAP2™ control mode. D-CAP2™ control combines constant on-time control with an internal compensation circuit for pseudo-fixed frequency and low external component count configuration with both low ESR and ceramic output capacitors. It is stable even with virtually no ripple at the output. At the beginning of each cycle, the high-side MOSFET is turned on. this MOSFET is turned off when the internal timer expires. This timer is set by the converter input voltage VIN, and the output voltage VO, to maintain a pseudo-fixed frequency over the input voltage range, hence it is called adaptive on-time control. The timer is reset and the high-side MOSFET is turned on again when the feedback voltage falls below the nominal output voltage. An internal ramp is added to the reference voltage to simulate output ripple, eliminating the need for ESR induced output ripple from D-CAP2™ mode control.