US 9,837,913 B1 · Control method to avoid capacitive mode switching for resonant converters

Abstract

A resonant power converter is provided with capacitive switching mode protection. The converter produces output current and voltage according to an operating frequency, which is desirably maintained above a resonant frequency for the power converter. A controller regulates the operating frequency based on an output current relative to a reference value, which may be provided via a dimming interface. A capacitive switching mode is determinable, based on a positive relationship in a detected direction of change in an output value relative to a detected direction of change in the operating frequency. When the capacitive switching mode is determined, a preceding operating frequency is enacted and the controller disables regulation of the operating frequency therefrom. Inductive mode switching is determinable with a negative relationship between detected direction of change in the output value relative to direction of change in the operating frequency, wherein regulation of operating frequency is renewed.

Claims16

Dependent claims

A method of avoiding capacitive switching in a resonant power converter having an operating frequency, the method comprising:

generating one or more feedback signals representing respective output values of the resonant power converter;
regulating the operating frequency of the resonant power converter based at least on a value of a first feedback signal relative to a reference value;
determining a capacitive switching mode of operation for the resonant power converter based on a detected direction of change in an output value relative to a detected direction of change in the operating frequency;
and
setting the operating frequency to a preceding operating frequency and disabling regulation of the operating frequency therefrom.

2 more elements

A resonant power converter, comprising:

first and second switching elements coupled across a DC source and configured for switching at an operating frequency in accordance with gate drive signals from a controller;
a resonant circuit coupled between an isolation transformer primary winding and an output node between the first and second switching elements;
an output stage coupled to a secondary winding of the isolation transformer and having one or more sensing circuits configured to provide at least a first feedback signal representative of one or more output values for the output stage;
and
the controller configured to
regulate the operating frequency of the first and second switching elements based at least on the output value associated with the first feedback signal relative to a reference value,
determine a capacitive switching mode of operation for the resonant power converter based on a detected direction of change in an output value relative to a detected direction of change in the operating frequency;
and
set the operating frequency to a preceding operating frequency and disable regulation of the operating frequency therefrom.

6 more elements

Dependencies are inferred from the claim text.

Control method to avoid capacitive mode switching for resonant converters

Life of this patent

Control method to avoid capacitive mode switching for resonant converters

Life of this patent

Abstract

Claims16