Contactless power transmission circuit
First Claim
1. A contactless power transmission circuit for transmitting a power via a magnetic field from a power transmitting coil to a power receiving coil, comprising:
- a driving circuit for supplying an alternating voltage to the power transmitting coil,a rectifier circuit for rectifying a voltage generated in the power receiving coil with a magnetic field generated by the power transmitting coil,a transmission current detecting circuit for detecting a transmission current flowing through the power transmitting coil,an output voltage detecting circuit for detecting an output voltage of the rectifier circuit, anda control circuit for controlling a period of the alternating voltage output from the driving circuit,wherein the control circuit is set to calculate a first command value and a second command value which are command values for the period of the alternating voltage, and use a smaller one of either of the first command value and the second command value as a command value for the period of the alternating voltage,the first command value is a command value based on a difference between a detected value of the output voltage detected by the output voltage detecting circuit and a target value of the output voltage, and the second command value is a command value calculated based on a difference between a detected value of the transmission current detected by the transmission current detecting circuit and a target value of the transmission current.
1 Assignment
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Accused Products
Abstract
The present invention provides a contactless power transmission circuit which is capable of narrowing a fluctuation extent of an output voltage output by a power receiving coil via a rectifier circuit. The contactless power transmission circuit controls a period of an alternating voltage output from a driving circuit based on a smaller one of either of a first command value and a second command value. Here, the first command value is one based on a difference between a detected value of the output voltage from the rectifier circuit and a target value. The second command value is one calculated based on a difference between a detected value of a transmission current flowing through the power transmitting coil and a target value.
2 Citations
10 Claims
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1. A contactless power transmission circuit for transmitting a power via a magnetic field from a power transmitting coil to a power receiving coil, comprising:
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a driving circuit for supplying an alternating voltage to the power transmitting coil, a rectifier circuit for rectifying a voltage generated in the power receiving coil with a magnetic field generated by the power transmitting coil, a transmission current detecting circuit for detecting a transmission current flowing through the power transmitting coil, an output voltage detecting circuit for detecting an output voltage of the rectifier circuit, and a control circuit for controlling a period of the alternating voltage output from the driving circuit, wherein the control circuit is set to calculate a first command value and a second command value which are command values for the period of the alternating voltage, and use a smaller one of either of the first command value and the second command value as a command value for the period of the alternating voltage, the first command value is a command value based on a difference between a detected value of the output voltage detected by the output voltage detecting circuit and a target value of the output voltage, and the second command value is a command value calculated based on a difference between a detected value of the transmission current detected by the transmission current detecting circuit and a target value of the transmission current. - View Dependent Claims (2, 3, 4, 5)
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6. A contactless power transmission circuit for transmitting a power via a magnetic field from a power transmitting coil to a power receiving coil,
comprising: -
a driving circuit for supplying an alternating voltage to the power transmitting coil, a rectifier circuit for rectifying a voltage generated in the power receiving coil with a magnetic field generated by the power transmitting coil, a transmission current detecting circuit for detecting a transmission current flowing through the power transmitting coil, an output voltage detecting circuit for detecting an output voltage of the rectifier circuit, and a control circuit for controlling a period of the alternating voltage output from the driving circuit, wherein the control circuit comprises a target voltage setter for outputting a target value of the output voltage, a target current setter for outputting a target value of the transmission current, a first subtracter for subtracting an output of the output voltage detecting circuit from an output of the target voltage setter, a second subtracter for subtracting an output of the transmission current detecting circuit from an output of the target current setter, a first PFM controller which is connected to an output of the first subtracter and outputs a first command value which is a command value for the period of the alternating voltage, a second PFM controller which is connected to an output of the second subtracter and outputs a second command value which is a command value for the period of the alternating voltage, a comparator which connects an output of the first PFM controller to an inverted input and connects an output of the second PFM controller to a non-inverted input, a multiplexer which connects the output of the first PFM controller and the output of the second PFM controller to an input and connects an output of the comparator to a selection control input, wherein the multiplexer is set to select the output of the first PFM controller when the output of the comparator is a high level, and to select the output of the second PFM controller when the output of the comparator is a low level. - View Dependent Claims (7, 8, 9, 10)
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Specification