TRANSITIONING A POWER SUPPLY FROM A MODE TO ANOTHER MODE IN RESPONSE TO A LENGTH OF A PORTION OF A CURRENT PULSE

摘要

An embodiment of a power-supply controller includes a switching circuit and a transition circuit. The switching circuit is configured to generate a regulated output voltage by generating first current pulses at an approximately fixed frequency during a first mode, and generating second current pulses at a variable frequency during a second mode. And the transition circuit is configured to transition the switching circuitry from the first mode to the second mode in response to a length of one of the first current pulses. For example, a power supply may include such a power-supply controller to transition the supply from a PWM mode to a PFM mode under light-load conditions. To cause this transition at a predictable load point, the controller may monitor the lengths of the current pulses during the PWM mode, and may transition the supply to a PFM mode in response to the lengths being below a threshold.

主权项

1. A power-supply controller, comprising:
a switching circuit configured to generate a regulated output voltage by generating first current pulses at an approximately fixed frequency during a first mode, and second current pulses at a variable frequency during a second mode; and a transition circuit configured to transition the switching circuitry from the first mode to the second mode in response to a length of one of the first current pulses.