Sharp Kabushiki Kaisha Corporation

Al-aid Corporation

Toshiya Fujiyama

Masanori Inamori

Hiroki Doi

Hideyuki Imanaka

Syouji Sakurai

Ryohta Takahashi

Satoru Ito

Shigeyoshi Kitamura

Yasuo Kudara

Seijun Nishimura

The amount of power generated by a solar cell is used for charging more efficiently. An activation determination meansactivates a charging control circuitby allowing a maximum output current from a solar cellto a GND potential to flow and detecting that the output current is equal to or greater than current consumption of the charging control circuitinstead of monitoring an unstable output voltage from the solar cell. Thus, the charging control circuitcan be activated more precisely in comparison to a case where an output voltage is monitored under the condition that the charging control circuitis operated only by the amount of power generated by the solar cell. Thereby, a power instrumentis charged more efficiently with the amount of power generated by the solar cell.

Charging control unit

A flyback-type switching power supply circuit provided with a transformer including a primary coil and a secondary coil, and a switching element connected to the primary coil, comprising: a multiplying circuit for multiplying a first value obtained by multiplying the on-duty ratio of a secondary current flowing to the secondary coil by a predetermined first constant, and a second value obtained by multiplying the peak value of a primary current flowing to the primary coil by a predetermined second constant; and a switching control circuit for controlling switching of the switching element so that the result of multiplication by the multiplying circuit and a third value obtained by multiplying a reference voltage by a predetermined third constant match; and the flyback-type switching power supply circuit is configured so that at least one of the first constant, the second constant, and the third constant is variable by an external signal.

Switching power supply circuit and LED illumination device

There is provided a power-supply platform IC for realizing a parameter-deciding power-supply circuit, which, in order to decide a parameter of a power-supply circuit that supplies power to an electronic circuit IC (load), is connected to the electronic circuit IC (load) in place of the power-supply circuit. The power-supply platform IC includes: one or more transistor arrays that include a plurality of transistors operable as switching transistors; and a selecting circuit for selecting a transistor to be operated as a switching transistor from among the plurality of transistors, so as to control a size of the transistor that operates as a switching transistor, wherein the selecting circuit varies the size of the transistor as a parameter of the power-supply circuit, according to an external command.

Power-supply semiconductor integrated circuit, power-supply semiconductor integrated circuit system, development assisting system for power-supply circuit, and program and storage medium therefor

An LED terminal monitoring circuit detects an LED at the lowest potential among a plurality of parallel-connected LEDs. An analog signal selecting circuit gives a signal indicating the voltage of the detected LED to a boosting circuit. The boosting circuit performs a boosting operation on the basis of the condition of the detected LED at the lowest voltage and, consequently, a voltage sufficient for driving the LEDs in a current-control mode can be applied to all the LEDs. Signal lines not connected to LEDs are excluded from objects of a LED-switching control operation.

LED-switching controller and LED-switching control method

In a negative voltage output charge pump circuit, first a capacitor C is charged with a positive voltage Vin relative to a reference voltage, and then the high-potential terminal A of the capacitor C is made to conduct to the reference voltage and simultaneously the low-potential terminal B of the capacitor C is made to conduct to an output terminal OUT so that the voltage with which the capacitor C is charged is output as a negative voltage &minus;Vin. Here, at least one of the switching device DP that is kept on while the capacitor C is being charged so as to apply the reference voltage to the point B and the switching device DP that is kept on while the negative voltage is being output so as to make the point B conduct to the output terminal OUT is a depletion-type transistor. This configuration makes it possible to realize a negative voltage output charge pump circuit that is free from malfunctioning caused by a parasitic device, that operates with low loss, and that can be produced at low costs.

Negative voltage output charge pump circuit

A phase control circuit which can stabilize voltage control when used in a switching regulator, and a switching regulator using such a phase control circuit are provided. A switching circuit for generating a first and a second output signals having opposite polarities based on a clock signal, is provided. A PWM latch circuit, reset by a reset signal, for generating a third and a fourth output signals which have phases controlled with respect to the first and the second output signals respectively by a set signal produced based on a control signal and come to have opposite polarities, is provided. A delay circuit for delaying the rising of each of the first through the fourth output signals before outputting each of the first through the fourth output signals is provided for each output signal. A delay clock pulse width setting circuit for generating a delay pulse based on low level periods of the delayed first and second output signals is provided so as to reset the PWM latch circuit using the delay pulse as the reset signal.

Phase control circuit and switching regulator

A delay circuit in accordance with the present invention includes: a first I L inverter and a second I L inverter connected in cascade with each other; and a capacitor interposed between a ground and a connecting point of the first and second inverters, wherein: the delay circuit further includes a current adjusting circuit having at least one third I L inverter with a plurality of output terminals at least one of which is connected to an input terminal of the third I L inverter; and the current adjusting circuit is connected to adjust a charge current of the capacitor. The configuration provides a delay circuit of simple circuit structure that accounts for a small area in an integrated circuit and that is capable of introducing any given delay and also provides a ring oscillator incorporating the delay circuit.

Growing community of inventors

Tenri, Japan

Toshiya Fujiyama