Primary side regulated isolation volatge converter
AssigneeChengdu Monolithic Power Systems Co., Ltd.
InventorYike Li
Life of this patent
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Abstract
A primary side regulated isolation voltage converter. The primary side regulated isolation voltage converter comprises a control module and a ripple control circuit. The control module receives the voltage feedback signal and determines whether the isolation voltage converter operates in a light load state. When the isolation voltage converter operates in a light load state, the ripple control circuit senses the ripple of an output voltage signal to generate a ripple signal, and compare the ripple signal with a ripple threshold. When the ripple signal is larger than the ripple threshold, the isolation voltage converter jumps out the light load state.
Claims18
A primary side regulated isolation voltage converter, comprising:
- a storage element having a primary winding, a secondary winding and a tertiary winding, wherein the tertiary winding is configured to induct an output voltage signal of the isolation voltage converter to generate a voltage feedback signal;
- a controllable switch, coupled to the primary winding, wherein an input voltage signal is converted to the output voltage signal by switching the controllable switch on and off;
- a control module, configured to determine whether the isolation voltage converter is in a light load state, and further configured to receive the voltage feedback signal and to provide a first control signal based on the voltage feedback signal, wherein the first control signal is active when the voltage feedback signal is smaller than a voltage reference signal;
- a ripple control circuit, configured to sense ripples of the output voltage signal to generate a ripple signal when the isolation voltage converter is in the light load state, and further configured to compare the ripple signal with a ripple threshold to generate a second control signal, wherein when the ripple signal is larger than the ripple threshold, the second control signal is active;
- and
- a logic circuit, configured to receive the first control signal and the second control signal, and further configured to conduct a logic operation of the first control signal and the second control signal to generate a third control signal, wherein the third control signal is configured to turn the controllable switch on when either the first control signal or the second control signal is active.
A control circuit for a primary side regulated isolation voltage converter, comprising:
- a control module, configured to determine whether the isolation voltage converter is in a light load state, and further configured to receive a voltage feedback signal generated by a tertiary winding of a transformer of the primary side regulated isolation voltage converter, and further configured to provide a first control signal based on the voltage feedback signal, wherein the first control signal is active when the voltage feedback signal is smaller than a desired reference signal;
- and
- a ripple control circuit, configured to sense ripples of the output voltage signal to generate a ripple signal when the isolation voltage converter is in the light load state, and further configured to compare the ripple signal with a ripple threshold to generate a second control signal, wherein the second control signal is active when the ripple signal is larger than the ripple threshold;
- and
- wherein the control circuit is configured to turn a controllable switch of the primary side regulated isolation voltage converter on when either the first control signal or the second control signal is active.
A control method used for a primary side regulated isolation voltage converter, comprising:
- generating a voltage feedback signal by a tertiary winding of a transformer of the primary side regulated isolation voltage converter;
- determining whether the isolation voltage converter is in a light load state based on the voltage feedback signal;
- sensing ripples of an output voltage signal to generate a ripple signal once the isolation voltage converter is in a light load state;
- determining whether the ripple signal is larger than a ripple threshold;
- and
- jumping out the light load state once the ripple signal is larger than the ripple threshold.
Dependencies are inferred from the claim text.