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US 8,942,016 B2Granted
Power supply apparatus
AssigneeRohm Co., Ltd.
InventorsSatoru Nate, Hiroshi Hayashi
Life of this patent
Estimating the term…
Abstract
A second control circuit is configured to switch a pulse signal to a level which turns off a second switching transistor when a coil current that flows through a primary winding reaches a predetermined threshold current. The second control circuit is configured to start a switching operation when a power supply for an electronic device is turned on, to set the threshold current to a first value when an intermediate voltage is higher than a predetermined level, and to set the threshold current to a second value that is lower than the first value when the intermediate voltage is lower than a predetermined level. A first control circuit is configured to start a switching operation upon receiving an instruction from a microcontroller to start operating.
Claims7
A power supply apparatus comprising:
- a rectifier circuit configured to full-wave rectify AC voltage;
- a power factor correction circuit including a non-insulation type DC/DC converter configured to receive an output voltage of the rectifier circuit, and to generate a DC intermediate voltage, and configured to operate such that the phase of the input current matches the phase of the AC voltage thus rectified;
- an insulation type DC/DC converter configured to receive the intermediate voltage, and to convert the level of the intermediate voltage thus received;
- and
- a microcontroller configured to operate receiving the output voltage of the insulation type DC/DC converter,
- wherein the power factor correction circuit comprises:
- an inductor arranged such that the output voltage of the rectifier circuit is applied to its first terminal;
- a first switching transistor arranged between a second terminal of the inductor and a ground terminal;
- and
- a first control circuit configured to generate a first pulse signal having a duty ratio such that the intermediate voltage matches its target voltage, and to drive the first switching transistor according to the first pulse signal,
- and wherein the insulation type DC/DC converter comprises:
- a transformer;
- a second switching transistor arranged between a primary winding of the transformer and the ground terminal;
- and
- a second control circuit configured to generate a second pulse signal having a duty ratio such that the output voltage of the insulation type DC/DC converter matches its target voltage, to drive the second switching transistor according to the second pulse signal, and to switch the pulse signal to a level which turns off the second switching transistor when a coil current that flows through the primary winding reaches a predetermined threshold current,
- and wherein the second control circuit is configured to start a switching operation when a power supply for an electronic device is turned on, to set the threshold current to a first value when the intermediate voltage is higher than a predetermined level, and to set the threshold current to a second value that is lower than the first value when the intermediate voltage is lower than a predetermined level,
- and wherein the first control circuit is configured to start a switching operation upon receiving an instruction from the microcontroller to start operating.
14 more elements
A power supply apparatus comprising:
- a rectifier circuit configured to full-wave rectify AC voltage;
- a power factor correction circuit including a non-insulation type DC/DC converter configured to receive an output voltage of the rectifier circuit, and to generate a DC intermediate voltage, and configured to operate such that the phase of the input current matches the phase of the AC voltage thus rectified;
- an insulation type DC/DC converter configured to receive the intermediate voltage, and to convert the level of the intermediate voltage thus received;
- and
- a microcontroller configured to operate receiving the output voltage of the insulation type DC/DC converter,
- wherein the power factor correction circuit comprises:
- an inductor arranged such that the output voltage of the rectifier circuit is applied to its first terminal;
- a first switching transistor arranged between a second terminal of the inductor and a ground terminal;
- and
- a first control circuit configured to generate a first pulse signal having a duty ratio such that the intermediate voltage matches its target voltage, and to drive the first switching transistor according to the first pulse signal,
- and wherein the insulation type DC/DC converter comprises:
- a transformer;
- a second switching transistor arranged between a primary winding of the transformer and the ground terminal;
- and
- a second control circuit configured to generate a second pulse signal having a duty ratio such that the output voltage of the insulation type DC/DC converter matches its target voltage, to drive the second switching transistor according to the second pulse signal, and to switch the pulse signal to a level which turns off the second switching transistor when a coil current that flows through the primary winding reaches a predetermined threshold current,
- and wherein the second control circuit is configured to start a switching operation when a power supply for an electronic device is turned on, to set the threshold current to a first value after a predetermined period of time elapses after the power supply is turned on, and to set the threshold current to a second value that is lower than the first value until the predetermined period of time elapses,
- and wherein the first control circuit is configured to start a switching operation upon receiving an instruction from the microcontroller to start operating.
14 more elements
Dependencies are inferred from the claim text.