Murata Manufacturing Co., Ltd.

Takahiro Nagai

Tatsuya Hosotani

Koyo Kaiwa

An in vivo-implantable medical device includes a housing that includes a body part and a protruding part, and that forms a sealed inner space; a power-receiving coil in a part of the inner space and that receives power by interlinking with external magnetic flux generated by an AC current flowing in an externally located power-transmitting coil; and a circuit substrate including a power reception circuit electrically connected to the power-receiving coil. The body part includes a metallic biocompatible material and the protruding part includes a non-metallic biocompatible material. The protruding part is structured so that, for a magnetic path along which the external magnetic flux passes, a magnetic path in which the magnetic flux interlinks with the power-receiving coil while avoiding the body part is formed, and the protruding part reduces eddy current loss caused by eddy currents generated by the external magnetic flux interlinking with the body part.

Vivo-implantable medical device

A magnetic coupling coefficient between a power reception coil and a communication antenna is 0.3 or less. A power management circuit suppresses electromagnetic interference between the power reception coil and the communication antenna in a predetermined time period by causing a rectification stopping circuit to operate to keep the rectification stopping circuit in an operation state in the predetermined time period with a received power voltage exceeding a first threshold value and by changing a resonant frequency of a power reception resonant circuit to a frequency different from a frequency being used in a wireless communication circuit to keep the resonant frequency in a changed state.

Wireless power reception device

An IC card communicates with a reader/writer, which is induction-type read/write communication equipment, in a contactless manner. A power supply control circuit detects presence or absence of power reception in accordance with an output voltage of a power receiving circuit, detects presence or absence of predetermined communication by using an electronic functional circuit, starts to charge an electrical energy storage device by using a charging circuit when there is not the predetermined communication immediately after power reception is detected, and supplies power from a voltage conversion circuit to the electronic functional circuit without starting to charge the electrical energy storage device by using the charging circuit when there is the predetermined communication immediately after power reception is detected.

IC card and IC card system

A near-field communication device includes a communication antenna for near-field communication formed along a plane, an interface circuit connected to the communication antenna for making a signal of the near-field communication pass through the interface circuit, a wireless communication IC connected to the interface circuit for processing the signal of the near-field communication, a power reception coil arranged along the plane to surround the communication antenna, a resonant capacitor constituting, together with the power reception coil, a power reception resonant circuit, and a rectifying and smoothing circuit connected to the power reception resonant circuit. The power reception resonant circuit resonates at a frequency of the near-field communication, and magnetic flux generated in the vicinity of the power reception coil by a resonant current flowing through the power reception resonant circuit interlinks with the communication antenna.

Near-field communication device

A wireless power-receiving device with near field communication function includes a communication antenna on a flat surface for near field communication, an interface circuit connected to the antenna and allowing a signal in the near field communication to pass, a wireless communication IC that is connected to the interface circuit and processes the signal, a receiving coil on the flat surface, a resonant capacitor included, with the receiving coil, in a receiving resonant circuit, and a rectifying/smoothing circuit connected to the receiving resonant circuit. The receiving resonant circuit resonates at a frequency for the near field communication, a resonance current flowing through the receiving resonant circuit causes a current to flow through the coil, a main flux is generated near the coil, and a magnetic path of the main flux is isolated from a magnetic path of a magnetic flux for the near field communication interlinking with the antenna.

Wireless power-receiving device with near field communication function

An IC card communicates with a reader/writer, which is inductive read/write communication equipment, in a non-contact manner. The IC card includes a proximity detection circuit that detects a proximity state to the reader/writer, a near-field communication circuit, an electronic function circuit, an electricity storage device, and a power supply control circuit. The power supply control circuit controls, based on a detection result of the proximity detection circuit, power supply from the electricity storage device to the electronic function circuit. The IC card manages and controls presence/absence and timing of power supply from the electricity storage device to the electronic function circuit and effectively controls discharging of the electricity storage device and charging of the electricity storage device.

High-frequency power is supplied from a power transmitter to a power receiver using an electromagnetic resonance phenomenon between the power transmitter and the power receiver. The power receiver converts the high-frequency power into a power reception direct-current power to charge a battery. A power reception control unit in the power receiver detects a state of charge of the battery and generates a power transmission stop signal on the basis of the state of charge of the battery. A resonance modulation circuit in the power receiver changes resonance conditions in response to the power transmission stop signal. An MPU in the power transmitter demodulates the power transmission stop signal based on an electric variable from a power transmission direct-current power supply due to a change in the resonance conditions and stops an operation of supplying the high-frequency power in a transmission power conversion circuit for a predetermined period.

Wireless power supply system

A wireless power transfer system includes a power transmitter including a high frequency power converter circuit that converts a direct current power into a high frequency power using a switching circuit, a power transmitter coil, and an electric field shield member close to the power transmitter coil and having a structure that uses a conductive member to form an equivalent capacitance between the electric field shield member and the power transmitter coil by electric coupling therebetween during a power transmitting operation such that the value of the equivalent capacitance becomes greater than the value of an equivalent capacitance formed between the power transmitter coil and ground. The power transmitter causes electric potentials in the electric field shield member to be identical using the conductive member, suppresses changes in an electric field in a vicinity of the power transmitter coil, and suppresses radiation of the electric field noise.

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Nagaokakyo, Japan

Takahiro Nagai