Abstract: A DC-DC converter including, an inductor; and a driving switching element for performing switching to a flow path to flow an electric current through the inductor; wherein the DC-DC converter drives the driving switching element by PWM control using a PWM control pulse to convert a direct-current input voltage supplied from a direct-current power source and to output a direct-current voltage having a piece of electric potential different from that of the direct-current input voltage, and wherein the DC-DC converter drives the driving switching element by the PWM control under a first condition, and the DC-DC converter makes the driving switching element be in an on-state continuously while the output direct-current voltage is lower than a desired level under a second condition.

Abstract: Provided is a DC-DC converter comprising: a drive switching element so that a current flows to an inductor, the drive switching element being driven by a PWM control pulse or a PFM control pulse, wherein a direct-current input voltage supplied from a direct-current power source is converted so as to output the converted direct-current voltage having a different potential, and wherein a PWM control is performed when a load is larger than a predetermined value and a PFM control is performed when the load is smaller than the predetermined value, the DC-DC converter further comprising: a pulse width regulation section to regulate the PWM control pulse so as not to have a pulse width smaller than a predetermined pulse width, at least when the PFM control is switched to the PWM control.

Abstract: The invention is directed to a semiconductor device having a diode element which prevents a leakage current due to a vertical parasitic bipolar transistor and enhances current efficiency. An element isolation insulation film is provided on an N well layer, and a first P+ layer and a second P+ layer are formed on the N well layer surrounded by the element isolation insulation film, the second P+ layer being formed at a distance from the first P+ layer. An electrode layer is formed on the N well layer between the first P+ layer and the second P+ layer. An N+ layer for a contact is formed on the N well layer between the element isolation insulation film and other element isolation insulation film. The first P+ layer is connected with an anode wiring, and the electrode layer, the second P+ layer, and the N+ layer are connected with a cathode wiring. A diode element utilizing a lateral PNP bipolar transistor is thus formed on the semiconductor substrate.

Abstract: Disclosed is a direct-current power supply device, including: an inductor; a switching element to intermittently supply a current to the inductor; an output terminal connected to an external unit; a rectifying element connected between the inductor and the output terminal; a PFM comparator to generate a first pulse signal having a pulse width corresponding to a voltage proportional to an output current of the external unit; a duty control circuit to generate a second pulse signal by controlling a pulse width of an oscillation signal having a predetermined frequency in response to an externally-supplied current control signal; a logic circuit configured to output the second pulse signal during a period when the first pulse signal is at a predetermined level; and a drive circuit to generate a drive signal for driving the switching element based on the second pulse signal.

Abstract: An AC adapter includes an AC/DC converter device for transforming an alternating-current power to a direct-current power, a power supply line that supplies the direct-current power converted by the AC/DC converter device to an electronic apparatus, and a memory for storing an AC adapter ID that identifies the AC adapter.

Abstract: The invention is directed to a semiconductor device having a diode element which prevents a leakage current due to a vertical parasitic bipolar transistor and enhances current efficiency. An element isolation insulation film is provided on an N well layer, and a first P+ layer and a second P+ layer are formed on the N well layer surrounded by the element isolation insulation film, the second P+ layer being formed at a distance from the first P+ layer. An electrode layer is formed on the N well layer between the first P+ layer and the second P+ layer. An N+ layer for a contact is formed on the N well layer between the element isolation insulation film and other element isolation insulation film. The first P+ layer is connected with an anode wiring, and the electrode layer, the second P+ layer, and the N+ layer are connected with a cathode wiring. A diode element utilizing a lateral PNP bipolar transistor is thus formed on the semiconductor substrate.

Abstract: A battery protection method is disclosed for protecting a battery from an over-discharge state by switching off a switching element provided between the battery and a load in accordance with the voltage of the battery. The method includes the steps of detecting application of a charging voltage and arranging a chargeable state for the battery by switching on the switching element when the application of the charging voltage is detected.

Abstract: A battery protection method is disclosed for protecting a battery from an over-discharge state by switching off a switching element provided between the battery and a load in accordance with the voltage of the battery. The method includes the steps of detecting application of a charging voltage and arranging a chargeable state for the battery by switching on the switching element when the application of the charging voltage is detected.

Abstract: A voltage-controlled oscillator includes a varactor diode which is a capacitance element coupled to a resonance circuit. A control voltage is applied to one end of the varactor diode and the output voltage of a variable DC voltage source which is capable of changing a voltage value stepwise is applied to the other end of the varactor diode via a voltage divider. Accordingly, the voltage-controlled oscillator can be operated as a local oscillator used for two communication systems. Further, a switching element is not required and thus deterioration in the characteristics caused by a reduction in the Q factor of the resonance circuit can be prevented. In addition, the power consumption does not increase.

Abstract: A voltage-controlled oscillator includes a varactor diode which is a capacitance element coupled to a resonance circuit. A control voltage is applied to one end of the varactor diode and the output voltage of a variable DC voltage source which is capable of changing a voltage value stepwise is applied to the other end of the varactor diode via a voltage divider. Accordingly, the voltage-controlled oscillator can be operated as a local oscillator used for two communication systems. Further, a switching element is not required and thus deterioration in the characteristics caused by a reduction in the Q factor of the resonance circuit can be prevented. In addition, the power consumption does not increase.

Abstract: A semiconductor memory capable of attaining a long life, a low voltage, a high-speed operation, low power consumption and high integration is provided. The semiconductor memory comprises a control gate electrode, a floating gate electrode, a semiconductor region, a first insulator film formed on one surface of the semiconductor region and a second insulator film formed on another surface of the semiconductor region. A prescribed voltage is applied to the control gate electrode or a drain region thereby injecting carriers from the control gate electrode or the drain region into the floating gate electrode through the first insulator film, the semiconductor region and the second insulator film.

Abstract: A selected inductance can be provided by a three-layer structural spiral inductor having an inductor conductive part disposed between two ground electrodes within an electric insulating substrate. This is carried out by eliminating a particular portion of one of those ground electrodes formed on the outer surface of the substrate until a desired inductance is obtained, beginning at a portion of such electrode corresponding to an exposed part of a through hole joint which is electrically connected to an inner peripheral end of a spiral inductor conductive part.

Abstract: A UHF transistor mixer circuit includes a transistor having a base to which an inputted high-frequency signal and a local oscillation signal are inputted. A bias voltage is applied to the base from a direct current voltage source through an inductor constructed with a microstripline. A low-pass filter which prevents signal components in the UHF band from being passed therethrough is provided between the base and the voltage source, and more particularly between the inductor and the direct current voltage source. The local oscillation signal is prevented from flowing toward the direct current voltage source by the low-pass filter, and therefore, the intermodulation distortion of the mixer circuit can be improved.

Abstract: A UHF band transistor mixer circuit includes a frequency converting transistor to a base of which a received high-frequency signal and a local oscillation signal are applied. A collector of the frequency converting transistor is connected to a low-pass filter from which a desired frequency signal, i.e., an intermediate frequency signal is outputted. A series resonance circuit having a series resonance frequency point existing in a frequency region between both the signals is connected between an emitter of the frequency converting transistor and a reference potential.