Rohm Co., Ltd.

Xun He

Daisuke Uchimoto

Naoki Inoue

Takeshi Nozawa

Sayako Hamaguchi

A controller controls an inverter. A signal level detection circuit generates a detection value Sthat corresponds to a voltage at a connection node that connects a series resonance capacitor and multiple transmission coils. The controller (i) drives the inverterwhile sequentially selecting the multiple transmission coils, and acquires the detection value Sfrom the signal level detection circuit. Furthermore, the controller (ii) determines a single transmission coil to be used for power supply, based on comparison results of the detection values Sacquired for each transmission coil.

Wireless power transmission apparatus and control method for the same

First, a power receiving apparatus RX is detected (S). Subsequently, a pre digital ping is sent according to a first method (S). Upon reception of an unique signal defined for the first method from the power receiving apparatus RX (YES in S), tentative judgment is made that the power receiving apparatus RX supports the first method, and the flow transits to a final judgment operation (S). When such an unique signal has not been received (NO in S), tentative judgment is made that the power receiving apparatus RX supports a second method, and the flow transits to a final judgment operation (S).

A control circuit is provided for a power receiver apparatus. A target voltage range setting unit sets an upper limit voltage Vand a lower limit voltage Vthat define a target voltage range REF to be set for a rectified voltage Vthat develops across a smoothing capacitor. An electric power control unit compares the rectified voltage Vwith each of the upper limit voltage Vand the lower limit voltage V, and generates a power control signal Dbased on the comparison result. A modulator modulates the power control signal D, and transmits the modulated signal to a wireless power transmitter apparatus via a reception coil. Upon detection of an oscillation state in the rectified voltage V, the target voltage range setting unit expands the target voltage range REF.

Power receiver control circuit for wireless power receiver apparatus

A control circuit of a wireless power receiver where the wireless power receiver includes a reception coil, a rectification circuit that rectifies a current of the reception coil, and a smoothing capacitor connected to an output of the rectification circuit. The control circuit includes a frequency detecting part configured to determine a frequency of a signal received by the reception coil in a detection period after a lapse of predetermined first time from a predetermined start timing before a lapse of predetermined second time; a modulation detecting part configured to determine whether the signal received by the reception coil is subjected to FSK (Frequency Shift Keying); and a standard determining part configured to determine a standard that a wireless power transmitter complies with, depending on the frequency detected by the frequency detecting part and the presence or absence of FSK.

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Kyoto, Japan

Xun He