USB power supply apparatus
First Claim
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1. A USB power supply apparatus that conforms to the USB (Universal Serial Bus) specification, and that supplies electric power to a USB power reception apparatus, the USB power supply apparatus comprising:
- a power supply circuit;
a bus line structured to connect an output of the power supply circuit and the USB power reception apparatus;
a switch provided on a path of the bus line;
a feedback circuit structured to feedback control the power supply circuit such that the output voltage of the power supply circuit approaches a reference voltage; and
a controller structured to adaptively control the reference voltage based on an electrical state of the USB power supply apparatus;
wherein the controller controls the reference voltage so as to reduce an amount of a drop in voltage from a predetermined setting voltage that occurs in a bus voltage at a position that is closer to the USB power reception apparatus side than the switch;
wherein the controller comprises a bus voltage detection unit structured to detect the bus voltage,wherein the controller controls the reference voltage based on a detection result obtained by the bus voltage detection unit;
wherein the bus voltage detection unit compares the bus voltage with a first threshold voltage determined to be lower than the setting voltage, and generates a low voltage detection signal which is asserted when the bus voltage becomes lower than the first threshold voltage;
wherein, when the low voltage detection signal is asserted, the controller raises the reference voltage by a predetermined voltage increment;
wherein the bus voltage detection unit compares the bus voltage with a second threshold voltage that is set to the setting voltage or otherwise a value in the vicinity of the setting voltage;
wherein the bus voltage detection unit generates a voltage return signal that is asserted when the bus voltage exceeds the second threshold voltage;
and wherein, when the voltage return signal is asserted, the controller lowers the reference voltage by a predetermined voltage decrement.
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Abstract
A USB power supply apparatus supplies electric power to a USB power reception apparatus. A bus line connects the output of the power supply circuit and the USB power reception apparatus. A switch is provided on a path of the bus line. A feedback circuit feedback controls the power supply circuit such that the output voltage VOUT of the power supply circuit approaches a reference voltage VREF. A controller adaptively controls the reference voltage VREF based on an electrical state of the USB power supply apparatus.
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Citations
13 Claims
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1. A USB power supply apparatus that conforms to the USB (Universal Serial Bus) specification, and that supplies electric power to a USB power reception apparatus, the USB power supply apparatus comprising:
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a power supply circuit; a bus line structured to connect an output of the power supply circuit and the USB power reception apparatus; a switch provided on a path of the bus line; a feedback circuit structured to feedback control the power supply circuit such that the output voltage of the power supply circuit approaches a reference voltage; and a controller structured to adaptively control the reference voltage based on an electrical state of the USB power supply apparatus; wherein the controller controls the reference voltage so as to reduce an amount of a drop in voltage from a predetermined setting voltage that occurs in a bus voltage at a position that is closer to the USB power reception apparatus side than the switch; wherein the controller comprises a bus voltage detection unit structured to detect the bus voltage, wherein the controller controls the reference voltage based on a detection result obtained by the bus voltage detection unit; wherein the bus voltage detection unit compares the bus voltage with a first threshold voltage determined to be lower than the setting voltage, and generates a low voltage detection signal which is asserted when the bus voltage becomes lower than the first threshold voltage; wherein, when the low voltage detection signal is asserted, the controller raises the reference voltage by a predetermined voltage increment; wherein the bus voltage detection unit compares the bus voltage with a second threshold voltage that is set to the setting voltage or otherwise a value in the vicinity of the setting voltage; wherein the bus voltage detection unit generates a voltage return signal that is asserted when the bus voltage exceeds the second threshold voltage; and wherein, when the voltage return signal is asserted, the controller lowers the reference voltage by a predetermined voltage decrement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification