DIGITAL PULSE-FREQUENCY MODULATION CONTROLLER FOR SWITCH-MODE POWER SUPPLIES WITH FREQUENCY TARGETING AND ULTRASONIC MODES

摘要

A digital pulse controller uses digital logic to send pulses to a high side and low side switches of a switch-mode power supply converter. The digital logic uses a pulse frequency mode which includes a frequency targeting mode and an ultrasonic mode. The frequency targeting mode dynamically adjusts the size of the pulses in order to achieve a switching frequency within a desired band. The ultrasonic mode is switched into when the frequency of the pulses are at or below a threshold and the time of the pulses reaches a minimum threshold.