Electromagnetic Interference (EMI) for Pulse Frequency Modulation (PFM) Mode of a Switching Regulator

摘要

A circuit and method providing switching regulation configured to provide a pulse frequency modulation (PFM) mode of operation with reduced electromagnetic interference (EMI) comprising an output stage configured to provide switching comprising a first and second transistor, a sense circuit configured to provide output current information sensing from an output stage and a current limit reference, a first digital-to-analog converter (DAC) configured to provide signal to the current limit reference, an adder function configured to provide a signal to the first digital-to-analog converter (DAC), and a linear shift feedback register (LSFR) configured to provide a signal to an adder function followed by the first digital-to-analog converter (DAC), and the LSFR receives a clock signal from said output stage.

主权项

1. A power converter running in a pulse frequency modulation (PFM) mode, comprising:
an output stage configured to provide switching comprising a first and second transistor; a controller configured to switch between said first and second transistors based on a current limit; a sense circuit configured to provide output current information sensing from said output stage and a current limit reference; and a current limit jitter block configured to jitter said current limit and spread an emission spectrum.