Rohm Co., Ltd.

Daisuke Uchimoto

Manabu Oyama

Naoki Inoue

Tatsuya Iwasaki

Hiroki Kikuchi

Takeshi Nozawa

Kazuyoshi Yasuoka

Xun He

Masatoshi Watanabe

Hiroaki Ando

Yoju Imamura

A wireless power receiver receives a power signal from a wireless power transmitter, the wireless power receiver including a reception antenna including a reception coil, a rectifier circuit that rectifies a current of the reception antenna, a plurality of position detection coils provided near the reception coil or provided to overlap the reception coil, and a position detection unit that detects a positional relation between the position detection coils and a transmission coil of the wireless power transmitter based on a detection signal indicating an electrical state of the position detection coils. An electronic device includes the wireless power receiver. Another electronic device includes a wireless power receiver that receives a power signal from a wireless power transmitter and that can detect a position of a transmission coil of the wireless power transmitter, and a notification unit that notifies a user of information based on the position of the transmission coil.

Wireless power receiver and electronic device

A transmission coil used in a wireless power transmitter includes a first coil, a second coil electrically connected in series with the first coil, and a tap provided at a connection node of the first coil and the second coil, the first coil and the second coil being stacked to at least partially overlap with each other. A transmission antenna includes the transmission coil, a first capacitor and a second capacitor connected in series with the transmission coil, and a switch provided in parallel to a series connection circuit of the second coil of the transmission coil and the second capacitor. A wireless power transmitter includes the transmission antenna and a bridge circuit that drives the transmission antenna. A charger includes the wireless power transmitter.

Transmission coil for wireless power supply, transmission antenna, wireless power transmitter, and charger

A rectifier circuit rectifies the current that flows through a reception coil. A smoothing capacitor is coupled to the output of the rectifier circuit. A power supply circuit stabilizes the rectified voltage Vthat occurs across the smoothing capacitor, and supplies the rectified voltage thus stabilized to a load. A dump circuit sinks the first dump current Ifrom the output of the power supply circuit. A current detection circuit detects the current Ithat flows through the power supply circuit, and generates a current detection signal Sthat indicates the amount of the current.

Wireless power receiver apparatus

A reception antenna includes a reception coil which receives a power signal. A rectification circuit rectifies an alternating current flowing to the reception antenna. A smoothing capacitor smoothes an output of the rectification circuit. A waveform stabilizer is enabled when a power receiver satisfies a predetermined condition and shifts a parallel resonance frequency of the reception antenna.

Wireless power receiver

A wireless power receiver that receives a power signal from a wireless power transmitter includes: a receiving antenna including a receiving coil for receiving the power signal; a rectifying circuit configured to rectify an alternating current flowing through the receiving antenna; a smoothing capacitor configured to smooth an output of the rectifying circuit; an overvoltage detecting circuit configured to compare a rectified voltage generated in the smoothing capacitor with an overvoltage threshold; a modulator configured to change a parallel resonance frequency of the receiving antenna; and a discharging circuit configured to be switched between an enable state and a disable state and configured to enter the enable state during a communication period by the modulator to discharge the smoothing capacitor.

Wireless power receiver, control method thereof, power receiving control circuit, and electronic apparatus

A power receiving apparatus is configured including a control circuit together with a reception coil, a rectifier circuit, a smoothing capacitor, and a modulator. A received power calculation unit calculates an electric power consumption Pof the wireless power receiving apparatus based on a predetermined calculation expression. A parameter acquisition unit acquires a first parameter &#x3b1; and a second parameter &#x3b2; via an external component. A correction unit calculates a received electric power Pof the wireless power receiving apparatus according to a correction expression P=&#x3b1;&#xd7;P+&#x3b2;.

Wireless power receiving apparatus

A rectifier circuit is coupled to a reception coil, and generates a rectified voltage. A charger circuit receives the rectified voltage, and charges a secondary battery. A modulator coupled to the reception coil modulates a voltage or a current applied to the reception coil based on a control value, and transmits a control packet including the control value to a wireless power transmitter. A charging control unit controls a charging current supplied from the charger circuit to the secondary battery. A power control unit generates a control error value indicating a power transmission rate for the wireless power transmitter, based on the difference between the present rectified voltage and its target value, and outputs the control error value as the control value to the modulator. When the absolute value of the difference is smaller than a predetermined threshold value, the charging control unit changes the charging current.

Control circuit for wireless power receiver and control method

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.

Power receiver control circuit, control method of wireless power receiver, and electronic apparatus

A power receiving control circuit is provided that receives AC coil current Ifrom a reception coil and that supplies DC output voltage V. A rectifier circuit rectifies the coil current I. A linear regulator receives a rectified voltage Vacross a smoothing capacitor, and generates the output voltage Vstabilized to a predetermined target level. A controller has predetermined control characteristics configured as a relation between the value of a charging current Iand the target value of the rectified voltage V. The controller detects the value of the charging current I, and transmits information which indicates electric power to be transmitted from a wireless power supply apparatus, with reference to the control characteristics. The controller is configured to be capable of changing the control characteristics.

Power receiving circuit, control method for wireless power receiving apparatus, and electronic device

A rectifier circuit rectifies a current that flows through a reception coil. A smoothing capacitor is connected to the output of the rectifier circuit. A judgment unit generates a notification signal that corresponds to a comparison result obtained by comparing the voltage Vacross the smoothing capacitor with a predetermined threshold voltage at a judgment timing. The judgment timing is positioned after the start of reception of a signal from a power supply apparatus.

A wireless power receiver circuit forms a wireless power receiving apparatus together with a reception coil. An internal power supply line is connected to a capacitor C. An output line is connected to a secondary battery. An H-bridge circuit includes N-channel MOSFETs MHMHMLand ML. A first switch is arranged between a rectification line and the internal power supply line. A second switch is arranged between the rectification line and the output line. A voltage Vof the internal power supply line is supplied to a power supply terminal of a controller.

Wireless power receiver circuit

A control IC controls a switching power supply configured to supply a driving voltage Vout to one terminal of an LED string to be intermittently driven. In the on period of the LED string, a pulse modulator generates a pulse signal having a duty ratio adjusted such that a detection voltage Vthat corresponds to the output voltage Vout of the switching power supply matches a predetermined reference voltage Vref. A driver drives a switching transistor included in the switching power supply according to the pulse signal. After transition from the on period to the off period, the pulse modulator reduces the duty ratio of the pulse signal over time.

Control circuit for switching power supply

A soft-start circuit generates a soft-start voltage Vss having a voltage level that rises over time. A pulse width modulator generates a PWM signal having a duty ratio adjusted such that a feedback voltage Vout' that corresponds to the output voltage Vout of the switching power supply matches the soft-start voltage Vss. A driver circuit controls a switching element according to the PWM signal. A capacitor is arranged such that one terminal thereof is set to a fixed electric potential. A current source generates a charge current that flows intermittently in synchronization with the PWM signal so as to charge the capacitor. The soft-start circuit outputs, as the soft-start voltage Vss, a voltage that occurs at the capacitor.

A control IC controls a switching power supply configured to supply a driving voltage Vout to one terminal of an LED string which is driven in an intermittent manner. A sample-and-hold circuit performs sampling of a detection voltage Vs that corresponds to a driving voltage Vout in the on period, and holds the sampled detection voltage Vs in the off period. In the off period, a pulse modulator generates a pulse signal having a duty ratio adjusted such that a hold detection voltage VsH output from the sample-and-hold circuit matches the detection voltage Vs. A driver drives a switching transistor according to the pulse signal.

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Kyoto, Japan

Daisuke Uchimoto