Sharp Kabushiki Kaisha Corporation

Kenji Hachimura

Tomohiro Suzuki

Zempei Tani

Hiromu Itoh

Tsuneo Matsumura

Noboru Kawai

Tatsuya Kato

Junichiro Kikunaga

A chopper-type regulator circuit includes an output transistor composed of a PNP-type transistor, and a control section for controlling switching of the output transistor based upon a voltage difference between a reference voltage and an output voltage. The control section is provided with a base current output terminal for supplying a base current of the output transistor to a load connected to the chopper-type regulator circuit.

IC wherein a chopper-type buck regulator PNP switch supplies base

A chopper-type regulator circuit includes an output transistor composed of a PNP-type transistor, and a control section for controlling switching of the output transistor based upon a voltage difference between a reference voltage and an output voltage. The control section is provided with a base current output terminal for supplying a base current of the output transistor to a load connected to the chopper-type regulator circuit. This makes it possible to reduce a loss of the circuit, thereby improving efficiency of the circuit.

Chopper-type regulator circuit and chopper-type regulator IC

A direct-current stabilizer includes an n-p-n transistor as a control transistor, and a control terminal to which a control voltage for driving the control transistor is applied. The value of the control voltage is determined so that a voltage applied to the base of the control transistor is not lower than the sum of the emitter voltage and the base-emitter voltage. With this structure, since the control transistor is driven by the control voltage of a value different from that of the input voltage, it is possible to limit the input voltage to a low value, allowing the difference between the input voltage and the output voltage to be minimized. Moreover, it is possible to switch the output of the direct-current stabilizer by connecting to the control terminal a transistor for switching the application of the control voltage to the control terminal between on and off. Furthermore, when the control terminal is connected to the input terminal, the control transistor is driven by the input voltage. Therefore, the direct-current stabilizer is used in the same manner as a conventional direct-current stabilizer is used.

Direct-current stabilizer

A light sensitive switching circuit for automatically controlling the supply of electric power from a power source to a load, such as a lantern, is disclosed. When it becomes darker than a predetermined brightness the power supply starts and when it becomes bright again, the power supply is cut. The light sensitive switching circuit comprises first and second lines for connecting the power source and the load in series between the first and second lines. A first thyristor is connected between the first and second lines, and a second thyristor connected is to the first thyristor such that the anode of the second thyristor is connected to the gate of the first thyristor and the cathode of the second thyristor is connected to the cathode of the first thyristor. A photocell is connected between the gate and the cathode of the second thyristor.

Light sensitive switching circuit

A position control system for positioning a D.C. motor at a desired position operates in a speed detection mode in which the D.C. motor is driven to rotate at a predetermined high speed, and in a position detection mode wherein the position of the D.C. motor is precisely controlled. In the speed detection mode, the control circuit forms a phase-locked-loop (PLL) control circuit which compares the phases of the speed instructing pulse signal and the rectangular signal derived from the actual rotation of the D.C. motor. The motor speed is controlled in accordance with the phase difference between the speed instructing pulse signal and the rectangular signal derived from the actual rotation of the D.C. motor.

Position control in a D.C. motor

A D.C. motor position control system operates either in the motor speed detection mode or in the motor position detection mode. A rotary encoder develops an approximate sinusoidal position indicating analog signal in response to the rotation of the D.C. motor. A waveform shaping circuit receives the approximate sinusoidal position indicating analog signal and develops a rectangular position indicating digital signal to a phase comparator which compares the phase of the rectangular position indicating digital signal with the phase of a speed instructing pulse signal so as to control the motor speed in a phase-locked-loop (PLL) manner in the motor speed detection mode. A slice level determination circuit divides the voltage level of the approximate sinusoidal position indicating analog signal into 16 (sixteen) degrees to obtain a sliced position indicating digital signal which is used to control the motor position in the motor position detection mode.

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Nara, Japan

Kenji Hachimura