Rohm Co., Ltd.

Hidetoshi Nishikawa

Masahiko Sonoda

A magnetic sensor circuit of the present invention includes: a Hall device; selection switch circuitswitching a detection state of the Hall deviceto either a first switch state or a second switch state; a comparator unitperforming comparison using a detection voltage of a magnetoelectric conversion deviceaid a predetermined reference voltage to generate a comparison result signal COUT; a logic circuitgenerating, based on an output signal OUT and the comparison result signal COUT, a logic operation signal LOUT for maintaining or inverting the logic of the output signal OUT; a latch circuitlatching the logic operation signal LOUT to output this as the output signal OUT; and a control circuit go determining, based on the output signal OUT, an order of switching the detection state of the Hall device(from the first switch state to the second switch state, or from the second switch state to the first switch state).

Magnetic sensor circuit and electronic apparatus using same

A Hall element outputs a Hall voltage generated at a first terminal pair or a second terminal pair to first and second output terminals by switching the voltage in a first status and a second status. Based on the voltages of the first and the second output terminals and a reference voltage, first and second capacitors are charged. Then, the voltages of the first and the second capacitors are compared, and a detection signal is obtained. Thus, a magnetic sensor circuit which reduces influence of an element offset voltage of the Hall element and also reduces influence of an input offset voltage generated at an amplifier, and a portable terminal provided with such magnetic sensor circuit are provided.

Magnetic sensor circuit and portable terminal provided with such magnetic sensor circuit

A sensor circuit has: a sensor portion that obtains, as an electrical signal, information on an object to be measured or detected; and a control circuit that controls the operation of the sensor portion. The control circuit receives a start input signal inputted thereto from outside for making the sensor portion operate only for a given duration after the start input signal is inputted thereto. With this configuration, it is possible to reduce the current consumption by arbitrarily controlling a period of an intermittent operation of the sensor circuit.

Sensor circuit, semiconductor device, and electronic apparatus

When the operation frequency is high, in order to cause the rate of change of outputs from an output terminal (OUT) to be abrupt, a selection control signal is caused to be in a low state, thereby causing MOS transistors (T, T) to be in ON states, thereby causing the combined resistance of the ON-resistances of the MOS resistors in a NOR gate (NOx) to be small. On the other hand, when the operation frequency is low, in order to cause the rate of change of outputs from the output terminal (OUT) to be gentle, the selection control signal is caused to be in a high state, thereby causing the MOS transistors (T, T) to be in OFF states, thereby causing the combined resistance of the ON-resistances of the MOS transistors in the NOR gate (NOx) to be large.

Semiconductor integrated circuit device

A semiconductor integrated circuit device () includes: a transistor switch (SWA) for electrically connecting and disconnecting output of a flip-flop (FF) of a shift register (SR) and input of a flip-flop (FF) of a shift register (SR); and a transistor switch (SWB) for electrically connecting and disconnecting an input driver (Din) and input of the flip-flop (FF). Here, when the shift registers (SRand SR) are connected, the transistor switch (SWA) is turned ON and the transistor switch (SWB) is turned OFF by a selection signal.

In a conventional N-channel MOSFET for an open-drain circuit, when a positive static electric charge is applied to its drain, there is no route by way of which to discharge the static electric charge, resulting in a rather low static withstand voltage. To overcome this, according to the invention, an open-drain N-channel MOSFET has a drain region formed of an N-type semiconductor layer, a P-type impurity diffusion layer formed within the drain region, two high-concentration N-type impurity diffusion layers formed within the drain region so as to sandwich the P-type impurity diffusion layer, and a drain electrode connected to the P-type impurity diffusion layer and to the two high-concentration N-type impurity diffusion layers. When a positive static electric charge is applied to the drain, a parasitic transistor appears that forms a route by way of which the static electric charge is discharged.

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Kyoto, Japan

Hidetoshi Nishikawa