Isolated power converter circuit and control method thereof
AssigneeRichtek Technology Corporation, R.O.C.
InventorsChia-Wei Liao, Jing-Meng Liu
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Abstract
The present invention discloses an isolated power converter circuit and a control method thereof. The isolated power converter circuit includes: a transformer circuit, a power switch circuit, an opto-coupler circuit, and a control circuit. The transformer circuit includes a first winding and a second winding. The power switch circuit is coupled to the transformer circuit to control it according to a driving signal. The opto-coupler circuit generates a feedback signal. The control circuit is coupled to the power switch circuit and the opto-coupler circuit, for generating the driving signal according to the feedback signal. The control circuit includes a distinguishing circuit for distinguishing a status of the feedback signal.
Claims14
An isolated power converter circuit, comprising:
- a transformer circuit, which includes a first winding and a second winding, configured to operably convert an input voltage to an output voltage;
- a power switch circuit, which is coupled to the first winding, configured to operably control the transformer to convert the input voltage to the output voltage according to a driving signal;
- an opto-coupler circuit, which has a first opto-coupler coupled to the second winding, configured to operably generate a feedback signal according to the output voltage;
- and
- a control circuit, which are coupled to the power switch circuit and the opto-coupler circuit, configured to operably generate the driving signal according to the feedback signal, wherein the control circuit includes:
- a distinguishing circuit configured to operably generate a distinguishing signal by directly or indirectly determining a status of the feedback signal;
- and
- a driving signal generation circuit configured to operably determine, by the distinguishing signal, whether or not generating the driving signal according to the feedback signal;
- wherein the isolated power converter circuit has a normal operation mode and a stand-by mode, wherein when the isolated power converter circuit operates in the stand-by mode, an opto-coupler current flowing through the opto-coupler circuit is less than a maximum level of the opto-coupler current flowing through the opto-coupler circuit when the isolated power converter circuit operates in the normal operation mode;
- wherein the opto-coupler circuit further comprises a second opto-coupler, which is coupled to the second winding, and configured to operably generate a stand-by signal according to the output voltage.
A control circuit of an isolated power converter circuit, wherein the isolated power converter circuit includes:
- a transformer circuit, which includes a first winding and a second winding, for converting an input voltage to an output voltage;
- a power switch circuit, which is coupled to the first winding;
- an opto-coupler circuit, having a first opto-coupler coupled to the second winding, for generating a feedback signal according to the output voltage, the control circuit comprising:
- a distinguishing circuit configured to operably generate a distinguishing signal by directly or indirectly determining a status of the feedback signal;
- and
- a driving signal generation circuit configured to operably determine, by the distinguishing signal, whether or not generating the driving signal according to the feedback signal;
- wherein the opto-coupler circuit further comprises a second opto-coupler, which is coupled to the second winding, and configured to operably generate a stand-by signal according to the output voltage, and the distinguishing circuit includes an enable circuit, which is coupled to the second opto-coupler, and configured to operably generate an enable signal functioning as the distinguishing signal according to the stand-by signal or a signal related to the stand-by signal.
A control method of an isolated power converter circuit, comprising:
- driving the isolated power converter circuit by a driving signal to convert an input voltage to an output voltage;
- generating a first opto-coupler current by opto-coupling according to the output voltage, for generating a feedback signal corresponding to the first opto-coupler current;
- generating a distinguishing signal by directly or indirectly determining a status of the feedback signal;
- determining by the distinguishing signal whether or not generating the driving signal according to the feedback signal;
- wherein the isolated power converter circuit has a normal operation mode and a stand-by mode, wherein when the isolated power converter circuit operates in the stand-by mode, the first opto-coupler current is less than a maximum level of the first opto-coupler current when the isolated power converter circuit operates in the normal operation mode;
- and
- generating a second opto-coupler current by opto-coupling according to the output voltage, for generating a stand-by signal.
Dependencies are inferred from the claim text.