US 10,541,618 B2 · Method and apparatus for measuring at least one of output current and output power for isolated power converters

Abstract

A flyback converter includes a primary-side switch connected to a primary-side winding of a magnetic device and a secondary-side switch connected to a secondary-side winding of the magnetic device. The flyback converter is operated by controlling the primary-side switch to store energy in the magnetic device during ON periods of the primary-side switch, switching on the secondary-side switch synchronously with switching off the primary-side switch to transfer energy from the magnetic device to the secondary side, determining an off time of the secondary-side switch based on a reflected input voltage measured at the secondary-side winding when the primary-side switch is on, accounting for a settling time of the reflected input voltage when determining the off time of the secondary-side switch so that the settling time has little or no effect on the off time, and switching off the secondary-side switch based on the off time.

Claims20

Dependent claims

A power converter, comprising:

a power switch device coupled to a magnetic device;
and
a controller configured to:
generate a switching signal for driving the power switch device, based on a feedback signal and a current sense signal which corresponds to a switching current of the magnetic device;
and
calculate at least one of an average output current and a maximum output power for the power converter, based on at least two measurements of the current sense signal taken during a turn-on period of the power switch device, a first one of the at least two measurements being taken at the end of a first time delay from the start of the turn-on period, a second one of the at least two measurements being taken when a magnitude of the current sense signal reaches a predefined threshold voltage assigned to the power switch device and above which the power switch device is designed to turn-off.

3 more elements

A method of operating a power converter having a power switch device coupled to a magnetic device, the method comprising:

generating a switching signal for driving the power switch device, based on a feedback signal and a current sense signal which corresponds to a switching current of the magnetic device;
capturing a first measurement of the current sense signal taken at the end of a first time delay from the start of a turn-on period of the power switch device;
capturing a second measurement of the current sense signal taken when a magnitude of the current sense signal reaches a predefined threshold voltage assigned to the power switch device and above which the power switch device is designed to turn-off;
and
calculating at least one of an average output current and a maximum output power for the power converter, based on at least the first and the second captured measurements of the current sense signal.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for measuring at least one of output current and output power for isolated power converters

Life of this patent

Method and apparatus for measuring at least one of output current and output power for isolated power converters

Life of this patent

Abstract

Claims20