Control circuit for switching power supply
First Claim
1. A control circuit structured to form a switching power supply together with an output circuit comprising an external circuit component, the control circuit comprising:
- a switching controller structured to control a switching element of the switching power supply; and
a degradation detection circuit structured to monitor a detection signal having a correlation with characteristic degradation of the external circuit component so as to detect a degree of characteristic degradation of the external circuit component;
wherein the switching controller is structured to change its operation according to the degree of characteristic degradation of the external circuit component;
wherein the degradation detection circuit comprises a calculation unit structured to calculate an estimated degradation value to be used as an index of the degree of characteristic degradation of the external circuit component based on the detection signal;
wherein the degradation detection circuit further comprises a judgment unit structure to compare the estimated degradation value with a predetermined first threshold value, and to generate a first control signal which is asserted when the estimated degradation value crosses the first threshold value; and
wherein, the switching controller is structured to raise a switching frequency of the switching power supply when the first control signal is asserted.
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Abstract
A power supply circuit is configured including a control circuit together with an output circuit including an external circuit component. A switching controller controls a switching transistor and a synchronous rectification transistor each configured as a switching element. A degradation detection circuit monitors a detection signal having a correlation with characteristic degradation of the circuit component, and detects the degree of characteristic degradation of the circuit component. The switching controller is capable of changing its operation according to the degree of characteristic degradation of the circuit component.
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Citations
15 Claims
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1. A control circuit structured to form a switching power supply together with an output circuit comprising an external circuit component, the control circuit comprising:
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a switching controller structured to control a switching element of the switching power supply; and a degradation detection circuit structured to monitor a detection signal having a correlation with characteristic degradation of the external circuit component so as to detect a degree of characteristic degradation of the external circuit component; wherein the switching controller is structured to change its operation according to the degree of characteristic degradation of the external circuit component; wherein the degradation detection circuit comprises a calculation unit structured to calculate an estimated degradation value to be used as an index of the degree of characteristic degradation of the external circuit component based on the detection signal; wherein the degradation detection circuit further comprises a judgment unit structure to compare the estimated degradation value with a predetermined first threshold value, and to generate a first control signal which is asserted when the estimated degradation value crosses the first threshold value; and wherein, the switching controller is structured to raise a switching frequency of the switching power supply when the first control signal is asserted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A power supply circuit comprising:
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an output circuit that comprises at least a switching element, an inductor, and an output line at which a DC output voltage develops according to a switching operation of the switching element; and a control circuit structured to control the switching element based on the DC output voltage, wherein the control circuit comprises; a switching controller structured to control the switching element of the switching power supply; and a degradation detection circuit structured to monitor a detection signal having a correlation with characteristic degradation of an external circuit component so as to detect a degree of characteristic degradation of the external circuit component; wherein the switching controller is structured to change its operation according to the degree of characteristic degradation of the external circuit component, wherein the degradation detection circuit comprises a calculation unit structured to calculate an estimated degradation value to be used as an index of the degree of characteristic degradation of the external circuit component based on the detection signal; wherein the degradation detection circuit further comprises a judgment unit structure to compare the estimated degradation value with a predetermined first threshold value, and to generate a first control signal which is asserted when the estimated degradation value crosses the first threshold value; and wherein, the switching controller is structured to raise a switching frequency of the switching power supply when the first control signal is asserted. - View Dependent Claims (14, 15)
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Specification