WIRELESS CHARGING CIRCUIT, WIRELESS CHARGING SYSTEM AND SEMICONDUCTOR DEVICE
First Claim
1. A wireless charging circuit comprising:
- a coil antenna;
a communication controller which can control short distance wireless communication performed via the coil antenna;
a rectifier circuit for rectifying an alternating-current signal obtained via the coil antenna; and
a power supply unit coupled to the rectifier circuit,wherein the power supply unit includes;
a voltage step-down circuit for reducing voltage of output of the rectifier circuit;
a charge control circuit for charging a battery by using the output of the voltage step-down circuit; and
a communication controller power supply circuit for forming an operational power supply voltage of the communication controller on the basis of the output of the voltage step-down circuit,wherein the voltage step-down circuit includes;
a switching regulator which can reduce the voltage output from the rectifier circuit;
a selection circuit which can select an output path of the switching regulator and a bypass path for bypassing the switching regulator; and
a selection control circuit which causes the selection circuit to select the bypass path at the time of activating the communication controller, to thereby supply voltage to the communication controller power supply circuit via the bypass path, and which causes the selection circuit to select an output path of the switching regulator after the output voltage of the switching regulator has reached a predetermined level, to thereby supply the output of the switching regulator to the communication controller power supply circuit.
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Accused Products
Abstract
To satisfy the NFC communication standard in wireless charging with a shared antenna, used for NEC communication.
A power supply unit includes a voltage step-down circuit 331, a charge control circuit 332, and a communication controller power supply circuit 333. The voltage step-down circuit includes a switching regulator 200, and a selection circuit 206 and 208 which can select an output path PT1 of the switching regulator and a bypass path PT2 of the switching regulator. The voltage step-down circuit includes a selection control circuit 207. The selection control circuit supplies voltage to the communication controller power supply circuit via the bypass path at the time of activating the communication controller. Since the output voltage of the series regulator stabilizes in a shorter time than the switching regulator, it becomes possible to keep the time from when RF power rises to when initial communication becomes possible, within standards.
284 Citations
13 Claims
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1. A wireless charging circuit comprising:
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a coil antenna; a communication controller which can control short distance wireless communication performed via the coil antenna; a rectifier circuit for rectifying an alternating-current signal obtained via the coil antenna; and a power supply unit coupled to the rectifier circuit, wherein the power supply unit includes; a voltage step-down circuit for reducing voltage of output of the rectifier circuit; a charge control circuit for charging a battery by using the output of the voltage step-down circuit; and a communication controller power supply circuit for forming an operational power supply voltage of the communication controller on the basis of the output of the voltage step-down circuit, wherein the voltage step-down circuit includes; a switching regulator which can reduce the voltage output from the rectifier circuit; a selection circuit which can select an output path of the switching regulator and a bypass path for bypassing the switching regulator; and a selection control circuit which causes the selection circuit to select the bypass path at the time of activating the communication controller, to thereby supply voltage to the communication controller power supply circuit via the bypass path, and which causes the selection circuit to select an output path of the switching regulator after the output voltage of the switching regulator has reached a predetermined level, to thereby supply the output of the switching regulator to the communication controller power supply circuit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A wireless charging system comprising:
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a power transmitting-side device; and a power receiving-side device which can receive power in a non-contact state from the power transmitting-side device, wherein the power receiving-side device includes; a coil antenna; a communication controller which can control short distance wireless communication performed with the power transmitting-side device, via the coil antenna; a rectifier circuit for rectifying an alternating-current signal obtained via the coil antenna; and a power supply unit coupled to the rectifier circuit, wherein the power supply unit includes; a voltage step-down circuit for reducing voltage of output of the rectifier circuit; a charge control circuit for charging a battery by using the output of the voltage step-down circuit; and a communication controller power supply circuit for forming an operational power supply voltage of the communication controller on the basis of the output of the voltage step-down circuit, wherein the voltage step-down circuit includes; a switching regulator which can reduce the voltage output from the rectifier circuit; a selection circuit which can select an output path of the switching regulator and a bypass path for bypassing the switching regulator; and a selection control circuit which causes the selection circuit to select the bypass path at the time of activating the communication controller, to thereby supply voltage to the communication controller power supply circuit via the bypass path, and which causes the selection circuit to select an output path of the switching regulator after the output voltage of the switching regulator has reached a predetermined level, to thereby supply the output of the switching regulator to the communication controller power supply circuit.
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8. A semiconductor device comprising:
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a rectifier circuit for rectifying an alternating-current signal obtained via an antenna; and a power supply unit coupled to the rectifier circuit, wherein the power supply unit includes; a voltage step-down circuit for reducing an output voltage of the rectifier circuit; and a power supply circuit for forming an operational power supply voltage of a communication controller which can control short distance wireless communication performed via the antenna, on the basis of an output voltage of the voltage step-down circuit, wherein the voltage step-down circuit includes; a switching circuit included in a DC-DC converter for reducing an output voltage of the rectifier circuit; a selection circuit which can select a first path between an output of the DC-DC converter and an input of the power supply unit circuit, and a second path which is different from the first path, between an output of the rectifier circuit and an input of the power supply unit circuit; and a selection control circuit which causes the selection circuit to select the second path at the time of activating the communication controller, and which subsequently, causes the selection circuit to select the first path after the output voltage of the DC-DC converter has reached a predetermined level or has stabilized. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification