Abstract: A power transmission device includes: a power reception unit that receives electric power from outside; a power transmission line that transmits the electric power received with the power reception unit to a battery; a transmission cut-off switch that cuts off the power transmission line, a transmission control circuit that uses the electric power received in the power reception unit as operation power, receives a battery state signal indicating a state of the battery, and switches conduction and non-conduction of the transmission cut-off switch on the basis of the battery state signal; and a cut-off control circuit that monitors the received electric power from the power reception unit by receiving electric power from the battery, and forcibly puts the transmission cut-off switch in a non-conductive state when the received electric power is less than a specified value.

Abstract: The present disclosure provides a wireless power receiver including: a power receiver configured to receive electrical power that is wirelessly transmitted from a wireless power transmitter; a power reception-side communication section configured to wirelessly communicate with the wireless power transmitter; a storage section to which data received by the power reception-side communication section is written by using the electrical power received by the power transmitter; and a monitoring section configured to monitor the electrical power or a voltage that corresponds to the electrical power supplied to the storage section in a case in which the data is being written to the storage section, the monitoring section transmits write information, which indicates whether or not the data was correctly written to the storage section based on a monitoring result, from the power reception-side communication section to the wireless power transmitter information.

Abstract: A filter circuit for generating a filtered signal includes a first filter unit, a second filter unit, and a negative feedback resistor. The first filter unit includes a signal input unit that receives signals, a signal output unit that outputs the filtered signals, and a non-ideal integrator and a first ideal integrator that are connected in series between the signal input unit and the signal output unit. The second filter unit includes an ideal integrator that is negative feedback-connected to the non-ideal integrator or the first ideal integrator. The negative feedback resistor is connected between the signal output unit and the signal input unit of the first filter unit.

Abstract: A wireless transmission device includes a reception circuit that receives a ASK or PSK designation signal designating amplitude-shift keying (ASK) or phase-shift keying (PSK), respectively, an amplitude control signal generation circuit that generates an amplitude control signal having an amplitude corresponding to a change in a signal level of the data signal, a polarity reversal circuit that generates a polarity reversal signal by reversing a polarity of a carrier wave signal according to the signal level of the data signal upon receiving a ASK designation signal, an amplifier circuit that generates a PSK signal by amplifying the polarity reversal signal at an amplification rate based on the amplitude control signal upon receiving a PSK designation signal, and generates an ASK signal by modulating an amplitude of the carrier wave signal at an amplification rate based on the amplitude control signal upon receiving the ASK designation signal.

Abstract: A filter circuit for generating a filtered signal includes a first filter unit, a second filter unit, and a negative feedback resistor. The first filter unit includes a signal input unit that receives signals, a signal output unit that outputs the filtered signals, and a non-ideal integrator and a first ideal integrator that are connected in series between the signal input unit and the signal output unit. The second filter unit includes an ideal integrator that is negative feedback-connected to the non-ideal integrator or the first ideal integrator. The negative feedback resistor is connected between the signal output unit and the signal input unit of the first filter unit.

Abstract: A power source circuit includes a power source terminal for inputting a power source voltage; a switching regulator including a switching circuit connected to the power source terminal and a smoothing circuit connected to the switching circuit; a series regulator connected to the switching regulator in series; a switching portion; and a control portion. The smoothing circuit includes a capacitor and an inductor to output a first voltage. The series regulator is connected to the switching circuit and the smoothing circuit in series to output a second voltage. The switching portion supplies the power source voltage to the series regulator. The control portion outputs a switching signal for controlling the switching portion to turn on or off according to the power source voltage.

Abstract: Upon sending out a first power-supply voltage having a first value to first and second power supply lines in a first mode and sending out a second power-supply voltage having a second value lower than the first value to the second power supply line in a second mode, when switching a power-supply device from the first mode to the second mode, the value of the first power-supply voltage generated in a first power-supply circuit is changed to the second value first, the first and second power supply lines are temporarily connected together and then cut off from each other, and then the generating operation of the first power-supply voltage is stopped.

Abstract: A power source circuit includes a power source terminal for inputting a power source voltage; a switching regulator including a switching circuit connected to the power source terminal and a smoothing circuit connected to the switching circuit; a series regulator connected to the switching regulator in series; a switching portion; and a control portion. The smoothing circuit includes a capacitor and an inductor to output a first voltage. The series regulator is connected to the switching circuit and the smoothing circuit in series to output a second voltage. The switching portion supplies the power source voltage to the series regulator. The control portion outputs a switching signal for controlling the switching portion to turn on or off according to the power source voltage.

Abstract: A receiving apparatus that includes a first and second filter circuit. The first filter performs filtering on a frequency signal with a band-pass characteristic such that a frequency band of a desired channel is included in a passband, thereby obtaining a pass frequency signal. The second filter performs filtering on the pass frequency signal with a filter characteristic such that a frequency band of a channel adjoining the desired channel is included in an attenuation band.

Abstract: Upon sending out a first power-supply voltage having a first value to first and second power supply lines in a first mode and sending out a second power-supply voltage having a second value lower than the first value to the second power supply line in a second mode, when switching a power-supply device from the first mode to the second mode, the value of the first power-supply voltage generated in a first power-supply circuit is changed to the second value first, the first and second power supply lines are temporarily connected together and then cut off from each other, and then the generating operation of the first power-supply voltage is stopped.

Abstract: A receiving apparatus that includes a first and second filter circuit. The first filter performs filtering on a frequency signal with a band-pass characteristic such that a frequency band of a desired channel is included in a passband, thereby obtaining a pass frequency signal. The second filter performs filtering on the pass frequency signal with a filter characteristic such that a frequency band of a channel adjoining the desired channel is included in an attenuation band.

Abstract: A wireless key system and location detection method determine whether a wireless key is located inside or outside a main body. A communication device in the main body transmits a wireless signal using an inner antenna and an outer antenna outside the main body having a different directivity. A wireless key measures direction of movement of the wireless key when the wireless signal is received by one of antennas having different directivities, detects one of the antennas receiving the highest signal level of the wireless signal as a first antenna, selects one of the antennas having the same directivity as the inner antenna as a second antenna according to the measured direction of movement and detected directivity of the antenna, and decides that the wireless key is inside the main body based on the signal levels of the wireless signals received by the first and second antennas.

Abstract: A semiconductor chip having a functional block that performs a communication function includes an input circuit that supplies an oscillating test signal to the functional block, and a test circuit that detects the strength of an oscillating signal which the functional block outputs in response. A strength signal indicating the detected strength is output from the test circuit through an external terminal of the semiconductor chip to a test device. The test device evaluates the strength signal to decide whether an operating characteristic of the functional block is within a specified range. The strength information indicated by the strength signal is not affected by impedance on the signal transmission line between the semiconductor chip and the test device, so the test is not affected by impedance loss.

Abstract: An oscillation circuit includes a resonance circuit and an amplifier circuit. The resonance circuit includes an inner capacitor to be disposed inside a semiconductor integrated circuit, and an outer capacitor and an outer inductor to be disposed outside the semiconductor integrated circuit. The amplifier circuit includes an input terminal and an output terminal both connected to the resonance circuit. Further, the resonance circuit includes a first closed circuit portion including the inner capacitor, the outer inductor, and a first wiring portion for connecting the inner capacitor and the outer inductor. The resonance circuit further includes a second closed circuit portion including the outer capacitor, the outer inductor, and a second wiring portion for connecting the outer capacitor and the outer inductor. The second closed circuit portion has a wiring resistance smaller than that of the first closed circuit portion.

Abstract: An electronic device includes a wireless receiving circuit for receiving signals transmitted from a remote control unit, a core circuit having a digital signal processing circuit for processing input signals and configured to perform at least one of display processing and record processing based on signals processed in the digital signal processing circuit in accordance with a control signal transmitted from the remote control unit and received by the wireless receiving circuit, and a preliminary activation circuit for starting electric power supply to the digital signal processing circuit to thereby activate the digital signal processing circuit when a pre-operation state where the remote control unit is expected to be operated during stoppage of electric power supply to the core circuit has occurred.

Abstract: A semiconductor chip having a functional block that performs a communication function includes an input circuit that supplies an oscillating test signal to the functional block, and a test circuit that detects the strength of an oscillating signal which the functional block outputs in response. A strength signal indicating the detected strength is output from the test circuit through an external terminal of the semiconductor chip to a test device. The test device evaluates the strength signal to decide whether an operating characteristic of the functional block is within a specified range. The strength information indicated by the strength signal is not affected by impedance on the signal transmission line between the semiconductor chip and the test device, so the test is not affected by impedance loss.

Abstract: A wireless key system and location detection method determine whether a wireless key is located inside or outside a main body. A communication device in the main body transmits a wireless signal using an inner antenna and an outer antenna outside the main body having a different directivity. A wireless key measures direction of movement of the wireless key when the wireless signal is received by one of antennas having different directivities, detects one of the antennas receiving the highest signal level of the wireless signal as a first antenna, selects one of the antennas having the same directivity as the inner antenna as a second antenna according to the measured direction of movement and detected directivity of the antenna, and decides that the wireless key is inside the main body based on the signal levels of the wireless signals received by the first and second antennas.

Abstract: The present invention aims to provide a reception frequency control circuit that is small in mounting area and unaffected by disturbance where an FSK-modulated signal is demodulated. In the reception frequency control circuit, a reception signal processing unit converts an FSK-modulated digital signal to an intermediate frequency when the FSK-modulated digital signal is received. Thereafter, a frequency voltage converting unit converts the intermediate signal to a voltage signal and outputs an output signal. At the same time, an analog frequency controlling unit detects a frequency deviation from the output signal by analog processing. A digital frequency controlling unit generates a reception frequency control signal for correcting the frequency and feeds back the same to the reception signal processing unit. Stable frequency control can be realized by performing reception frequency control by a combination of an analog circuit-digital circuit in this way.

Abstract: A wireless communication apparatus using a frequency signal produced by a frequency synthesizer operates at a reduced power consumption and includes a reception portion comprising a first mixer mixing a signal based on the received wireless signal and the frequency signal, a second mixer mixing the first mixer output signal and a local signal, and a demodulation stage demodulating the second mixer output signal. The frequency synthesizer comprises a Voltage Controlled Oscillator (VCO) generating a frequency signal responsive to a variation of a control input voltage, and a feed back circuit receiving as a control input voltage a voltage corresponding to a phase difference between a signal obtained by frequency dividing the output frequency signal of the VCO and a reference clock signal. The VCO is operable at a high frequency that increases with an increase of a bias current.

Abstract: An oscillation circuit includes a resonance circuit and an amplifier circuit. The resonance circuit includes an inner capacitor to be disposed inside a semiconductor integrated circuit, and an outer capacitor and an outer inductor to be disposed outside the semiconductor integrated circuit. The amplifier circuit includes an input terminal and an output terminal both connected to the resonance circuit. Further, the resonance circuit includes a first closed circuit portion including the inner capacitor, the outer inductor, and a first wiring portion for connecting the inner capacitor and the outer inductor. The resonance circuit further includes a second closed circuit portion including the outer capacitor, the outer inductor, and a second wiring portion for connecting the outer capacitor and the outer inductor. The second closed circuit portion has a wiring resistance smaller than that of the first closed circuit portion.