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US 9,178,431 B2Granted
Switching power supply including threshold based permissions
AssigneeFuji Electric Co., Ltd.
InventorJian Chen
Life of this patent
Estimating the term…
Abstract
Aspects of the invention provide a switching power supply that exhibits an improved conversion efficiency. In aspects of the invention, a load condition detecting circuit sets a threshold voltage for determining the magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended period of the power factor correction converter. An operation permission signal is delivered when a feedback voltage that indicates the magnitude of the load of the DC-DC converter exceeds the threshold voltage. When the feedback voltage exceeds a threshold voltage that is set at a value higher than the threshold voltage, the operation permission signal is delivered.
Claims7
A switching power supply comprising:
- a power factor correction converter that conducts switching of an input AC voltage to obtain a DC voltage;
- a DC-DC converter that conducts switching of an output voltage of the power factor correction converter to obtain a specified DC output voltage;
- and
- a load condition detecting circuit that delivers an operation permission signal to the power factor correction converter corresponding to a load condition of the DC-DC converter and permits or stops operation of the power factor correction converter;
- wherein the load condition detecting circuit
- sets a second threshold voltage and a third threshold voltage for determining a magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended state of operation of the power factor correction converter;
- delivers the operation permission signal when a signal indicating the magnitude of the load on the DC-DC converter changes from being below the second threshold voltage to exceeding the second threshold voltage for a specified period of time in a suspended state of operation of the power factor correction converter;
- and
- delivers the operation permission signal when the signal indicating the magnitude of the load on the DC-DC converter changes from being below the third threshold voltage to exceeding the third threshold voltage in a suspended state of operation of the power factor correction converter.
6 more elements
A switching power supply comprising:
- a power factor correction converter that conducts switching of an input AC voltage to obtain a DC voltage;
- a DC-DC converter that conducts switching of an output voltage of the power factor correction converter to obtain a specified DC output voltage;
- and
- a load condition detecting circuit that delivers an operation permission signal to the power factor correction converter corresponding to a load condition of the DC-DC converter and permits or stops operation of the power factor correction converter;
- wherein the load condition detecting circuit
- sets a second threshold voltage and a third threshold voltage for determining a magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended state of operation of the power factor correction converter;
- delivers the operation permission signal when a signal indicating the magnitude of the load on the DC-DC converter exceeds the second threshold voltage for a specified period of time in a suspended state of operation of the power factor correction converter;
- and
- delivers the operation permission signal when the signal indicating the magnitude of the load on the DC-DC converter exceeds the third threshold voltage in a suspended state of operation of the power factor correction converter wherein
- the load condition detecting circuit comprises, in a suspended state of operation of the power factor correction converter,
- a voltage detecting means that detects the maximum value of the output voltage of the power factor correction converter,
- the load condition detecting circuit sets the second threshold voltage and the third threshold voltage for determining the magnitude of the load on the DC-DC converter corresponding to the maximum value of the output voltage that is detected by the voltage detecting means.
9 more elements
A switching power supply comprising:
- a power factor correction converter that conducts switching of an input AC voltage to obtain a DC voltage;
- a DC-DC converter that conducts switching of an output voltage of the power factor correction converter to obtain a specified DC output voltage;
- and
- a load condition detecting circuit that delivers an operation permission signal to the power factor correction converter corresponding to a load condition of the DC-DC converter and permits or stops operation of the power factor correction converter;
- wherein the load condition detecting circuit
- sets a second threshold voltage and a third threshold voltage for determining a magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended state of operation of the power factor correction converter;
- delivers the operation permission signal when a signal indicating the magnitude of the load on the DC-DC converter exceeds the second threshold voltage for a specified period of time in a suspended state of operation of the power factor correction converter;
- and
- delivers the operation permission signal when the signal indicating the magnitude of the load on the DC-DC converter exceeds the third threshold voltage in a suspended state of operation of the power factor correction converter wherein
- the second threshold voltage and the third threshold voltage are set as threshold voltages for a feedback voltage that is used for controlling a DC output voltage in the DC-DC converter, and
- the load condition detecting circuit comprises:
- a flip-flop that delivers the operation permission signal when the flip-flop is reset;
- a light load detecting circuit that sets the flip-flop when the feedback voltage falls below a predetermined first threshold voltage;
- a middle load detecting circuit that resets the flip-flop when the feedback voltage exceeds, for a specified period of time, the second threshold voltage that is higher than the first threshold voltage and determined based on the maximum value of an input voltage to the DC-DC converter;
- and
- a heavy load detecting circuit that resets the flip-flop forcedly when the feedback voltage exceeds the third threshold voltage that is set at a value higher than the second threshold voltage.
13 more elements
A switching power supply comprising:
- a power factor correction converter that conducts switching of an input AC voltage to obtain a DC voltage;
- a DC-DC converter that conducts switching of an output voltage of the power factor correction converter to obtain a specified DC output voltage;
- and
- a load condition detecting circuit that delivers an operation permission signal to the power factor correction converter corresponding to a load condition of the DC-DC converter and permits or stops operation of the power factor correction converter;
- wherein the load condition detecting circuit
- sets a second threshold voltage and a third threshold voltage for determining a magnitude of the load on the DC-DC converter based on the maximum value of the output voltage of the power factor correction converter in a suspended state of operation of the power factor correction converter;
- delivers the operation permission signal when a signal indicating the magnitude of the load on the DC-DC converter exceeds the second threshold voltage for a specified period of time in a suspended state of operation of the power factor correction converter;
- and
- delivers the operation permission signal when the signal indicating the magnitude of the load on the DC-DC converter exceeds the third threshold voltage in a suspended state of operation of the power factor correction converter wherein
- the second threshold voltage and the third threshold voltage are set as threshold voltages for a periodic voltage that is proportional to a period of time of an ON/OFF driving period of an switching element in the DC-DC converter, and
- the load condition detecting circuit comprises:
- a flip-flop that delivers the operation permission signal when the flip-flop is reset;
- a light load detecting circuit that sets the flip-flop when the periodic voltage falls below a predetermined first threshold voltage;
- a middle load detecting circuit that resets the flip-flop when the periodic voltage exceeds, for a specified period of time, the second threshold voltage that is higher than the first threshold voltage and determined based on the maximum value of an input voltage to the DC-DC converter;
- and
- a heavy load detecting circuit that resets the flip-flop forcedly when the periodic voltage exceeds the third threshold voltage that is set at a value higher than the second threshold voltage.
13 more elements
Dependencies are inferred from the claim text.