Sanyo Electric Co., Ltd.

Sanyo Semiconductor Co., Ltd.

Takashige Ogata

Tatsuya Suzuki

Masahiro Ono

Masurao Yoshii

Shuhei Kawai

Toshiharu Oya

An amplifying circuit comprising an output stage circuit composed of a first and a second output transistor and operating as a class AB push-pull circuit reduces electricity consumed by an idle current. A pre-stage circuit outputs a first and a second control signal, and controls a channel current of the first and the second output transistor. In a period in which one control signal causes the corresponding output transistor to operate in class AB mode, the other control signal places the corresponding output transistor in a cutoff state.

Amplifying circuit

A step down DC-DC converter is reduced in the cost by reducing a number of capacitors included. The DC-DC converter is provided with switches that connect (n&#x2212;1) capacitors in parallel with each other and switches that connect the capacitors in series with each other. In phasesome switches are turned on to connect the capacitors in parallel between an output terminal and a ground voltage so that the capacitors are charged. In phaseother switches are turned on to connect the capacitors in series between the output terminal and an input voltage so that the capacitors are discharged. A stepped down output voltage, that is 1/n times of the input voltage, is obtained by alternating the phaseand the phaseuntil a stable state is reached.

DC-DC converter with switchable capacitors

A driver circuit to obtain a current to drive a light emitting device is reduced in a patterning area and improved in efficiency. A positive power supply voltage Vdd is applied to an anode of a white LED, while a voltage &#x2212;0.5 Vdd from a &#x2212;0.5 Vdd generation circuit is applied to a cathode of the white LED through an N-channel type MOS transistor. The &#x2212;0.5 Vdd generation circuit generates the voltage &#x2212;0.5 Vdd according to a clock &#x3a6; from a clock generation circuit. A voltage of 1.5 Vdd is applied between the anode and the cathode of the white LED, as equivalent to a prior art. Since N-channel type MOS transistors are heavily used in the &#x2212;0.5 Vdd generation circuit, the driver circuit requires less patterning area to obtain the same amount of current to drive the LED as in the prior art. In addition, a parasitic capacitance is reduced to improve efficiency of the driver circuit.

Driver circuit

It is an object to increase the number of rewriting timing permitted for a split-gate-type nonvolatile semiconductor memory device. Ends S of floating gate,are disposed in inclined portions of LOCOS oxide films,A and,B so as to sharpen projections of the floating gate to have an angle B.

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Gunma, Japan

Takashige Ogata