Device housing a battery and charging pad

Abstract

A device housing a battery (50) includes a receiving coil (51), and a charging pad (10) includes a transmitting coil (11) that magnetically couples with, and supplies charging power to the receiving coil. The device further includes a modulator circuit (61) that changes the impedance of the receiving coil according to internal battery data. The charging pad further includes a detection circuit (17) that detects receiving coil impedance changes to detect the battery data. The modulator circuit has a load circuit (62) connected in parallel with the receiving coil and has a series-connected switching device (64) and impedance modulating capacitor (63), and a control circuit (65) that switches the load circuit switching device ON and OFF according to the battery data. The modulator circuit switches the switching device (64) ON and OFF to transmit battery data to the charging pad.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a device housing a battery (or batteries) such as a battery pack or mobile telephone, and to a charging pad that transmits power by magnetic induction to the device housing a battery to charge the battery inside.[0003]2. Description of the Related Art[0004]A charging pad (charging stand, charging cradle) has been developed to charge a battery housed in a device by transmitting power from a transmitting coil (power supply coil, primary coil) to a receiving coil (induction coil, secondary coil) by magnetic induction. (Refer to Japanese Laid-Open Patent Publication H09-63655 (1997).)[0005]JP H09-63655A cites a configuration with a charging pad housing a transmitting coil driven by an alternating current (AC) power source, and a battery pack containing a receiving coil that magnetically couples with the transmitting coil.[0006]The battery pack houses circuitry to rectify AC power induced in ...

AI Technical Summary

Benefits of technology

The present invention aims to provide a device housing a battery and charging pad that can rapidly transmit battery information to the power supply-side charging pad in real-time while maintaining a simple circuit structure. The device has a detection circuit that can detect changes in the impedance of the receiving coil to accurately detect connection or disconnection of the impedance modulating capacitor to the receiving coil. The device also has a series capacitor connected in series with the receiving coil to efficiently transmit battery information while efficiently transmitting power. A synchronous rectifying circuit or a diode-bridge circuit can be used for efficient battery data transmission and battery short-circuit current flow reduction, respectively. A load circuit with a pair of series-connected switching devices and impedance modulating capacitors connected in series with each switching device can be used to transmit battery information accurately detecting the receiving coil position without a common ground line connection between the receiving coil and the rectifying circuit. This system allows for efficient battery charging.

Problems solved by technology

However, this configuration has the drawbacks that the circuit structure to transmit battery information from the battery-side to the power supply-side is complex, and it is difficult to accurately transmit rapidly varying battery data in real-time.

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