Wireless power receiving device, wireless power supply device, wireless power transmission system, and method for protecting wireless power receiving device from excessive magnetic field

• US 10,630,073 B2
• Filed: 05/10/2018
• Issued: 04/21/2020
• Est. Priority Date: 05/16/2017
• Status: Active Grant

• Current Assignee: LAPIS Semiconductor Co., Ltd. (ROHM Co., Ltd.)
• Original Assignee: LAPIS Semiconductor Co., Ltd. (ROHM Co., Ltd.)
• Inventors: Taya, Takashi
• Primary Examiner(s): Tran, Pablo N
• Application Number:
  US15/975,777
• Publication Number:
  US 20180337528A1
• Time in Patent Office: 712 Days
• CPC Class Codes: G05F 1/575 characterised by the feedback circuit
• CPC Class Codes: H02H 1/0007 concerning the detecting means in general G01R or other subclasses of G01; reed switches H01H71/2445
• CPC Class Codes: H02H 9/04 responsive to excess voltage lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/0064 Magnetic structures combining different functions, e.g. storage, filtering or transformation
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 7/06 using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

The disclosure provides a wireless power receiving device, a wireless power supply device, and a wireless power transmission system. The wireless power receiving device includes: a conversion unit that converts an alternative magnetic field into a reception voltage that has a voltage value corresponding to an amplitude of the alternative magnetic field; a power receiving circuit that generates a stabilized voltage with a fixed voltage value based on the reception voltage, and outputs an output voltage corresponding to the stabilized voltage via an output line; and a communication circuit that receives the stabilized voltage as a power-supply voltage to perform the data communication; the power receiving circuit includes a protection circuit that restricts an upper limit of the reception voltage to a first voltage value in the communication mode, and restricts the upper limit to a second voltage value higher than the first voltage value in the power supply mode.

Claims

1. A wireless power receiving device, which wirelessly implements, by an alternative magnetic field, a power supply mode in which supply of electric power is received and a communication mode in which data communication is performed in a time division manner, comprising:

a conversion unit that converts the alternative magnetic field into a reception voltage that has a voltage value corresponding to a magnetic field amplitude of the alternative magnetic field;

a power receiving circuit that generates a stabilized voltage with a fixed voltage value based on the reception voltage, and outputs an output voltage corresponding to the stabilized voltage via an output line; and

a communication circuit that receives the stabilized voltage as a power-supply voltage to perform the data communication;

wherein

the power receiving circuit comprises;

a protection circuit that restricts an upper limit of the reception voltage to a first voltage value in the communication mode, and restricts the upper limit of the reception voltage to a second voltage value higher than the first voltage value in the power supply mode.

2. The wireless power receiving device according to claim 1, comprising:

an operation state detection processing unit that detects an operation state of the power receiving circuit, wherein

the protection circuit varies the magnetic field amplitude of the alternative magnetic field by switching the upper limit of the reception voltage from the second voltage value to another voltage value in the power supply mode, and informs of the operation state by the variation of the magnetic field amplitude.

3. The wireless power receiving device according to claim 1, wherein when the alternative magnetic field is above a predetermined magnetic field strength, the protection circuit decreases a voltage value of the upper limit.

4. The wireless power receiving device according to claim 1, which comprises a voltage detection unit that detects a voltage value of the stabilized voltage, wherein

when the voltage value detected by the voltage detection unit is lower than a predetermined lower limit, the protection circuit stops the operation that restricts the upper limit of the reception voltage.

5. The wireless power receiving device according to claim 1, wherein the protection circuit comprises a current detection unit that detects a current amount of a current flowing in the protection circuit, and

in a case where the current amount detected by the current detection unit is less than a predetermined current value and in a case where the current amount is equal to or higher than the predetermined current value, the communication circuit performs the data communication with different communication properties.

6. The wireless power receiving device according to claim 1, wherein the power receiving circuit comprises a stabilization circuit that comprises:

a first line that receives the reception voltage;

a first transistor that generates the stabilized voltage based on the reception voltage of the first line and applies the stabilized voltage to the second line;

a second transistor that is connected to the first transistor in parallel via a first resistor; and

a first current detection circuit that detects a current transmitted to the second line, based on a potential difference between two ends of the first resistor.

7. The wireless power receiving device according to claim 1, wherein the power receiving circuit comprises:

a blocking circuit that blocks a supply of the output voltage to the output line according to an output blocking control signal,

the blocking circuit comprising;

a first MOS transistor that receives the output voltage with a drain and receives the output blocking control signal with a gate, and a source of which is connected to the output line;

a second MOS transistor, in which a current corresponding to the potential difference between the drain and source of the first MOS transistor flows; and

a second current detection circuit that detects a current amount of a current flowing in the second MOS transistor as a current amount of an output current flowing in the output line.

8. The wireless power receiving device according to claim 1, wherein the conversion unit comprises:

a power receiving coil that receives the alternative magnetic field;

a first capacitor and a second capacitor that are connected to one end of the power receiving coil in series; and

a rectifying circuit that converts a voltage of one end of the power receiving coil received via the first capacitor and the second capacitor to a direct-current voltage to obtain the reception voltage; and

the communication circuit is connected to a connecting point of the first capacitor and the second capacitor, and performs the data communication via the connecting point, the first capacitor, and the power receiving coil.

9. The wireless power receiving device according to claim 8, comprising:

a pull-up resistor that applies direct-current potential to the connecting point.

10. The wireless power receiving device according to claim 1, wherein the conversion unit comprises the power receiving coil that receives the alternative magnetic field, and

the communication circuit is connected to the power receiving coil, performs the data communication via the power receiving coil, and blocks a connection with the power receiving coil when the voltage value of the stabilized voltage is lower than a predetermined lower limit.

11. The wireless power receiving device according to claim 1, wherein the power receiving circuit comprises:

an output discharge circuit that comprises a switching element that is turned off in the power supply mode, and is turned on in the communication mode to apply grounding potential to the output line.

12. The wireless power receiving device according to claim 1, wherein the power receiving circuit is formed in a semiconductor chip included in an LSI package that comprises a first external terminal that receives the reception voltage and a second external terminal that externally outputs the output voltage;

in the LSI package;

a first wire that connects a first bonding pad formed in the semiconductor chip to the first external terminal,

a second wire that connects a second the bonding pad formed in the semiconductor chip to the first external terminal, and

a third wire that connects a third bonding pad formed in the semiconductor chip to the second external terminal, are formed; and

in the semiconductor chip;

the communication circuit,

a first stabilization circuit that generates a first stabilized voltage that is obtained by making a voltage value of the reception voltage received via the first bonding pad be constant, and applies the first stabilized voltage to the third bonding pad as the output voltage, and

a second stabilization circuit that generates a second stabilized voltage that is obtained by making a voltage value of the reception voltage received via the second the bonding pad be constant, and supplies the second stabilized voltage to the communication circuit as the power-supply voltage, are formed.

13. A method for protecting a wireless power receiving device from an excessive magnetic field, wherein the wireless power receiving device wirelessly implements, by an alternative magnetic field, a power supply mode in which supply of electric power is received and a communication mode in which data communication is performed in a time division manner, and obtains a reception voltage that has a voltage value corresponding to an amplitude of the alternative magnetic field, and wherein

an upper limit of the reception voltage in the communication mode is restricted to a first voltage value, and the upper limit of the reception voltage in the power supply mode is restricted to a second voltage value higher than the first voltage value.