Abstract: Provided is a complementary metal oxide semiconductor (CMOS) input buffer circuit that is capable of lower voltage operation with lower current consumption. The CMOS input buffer circuit includes: a depletion type NMOS transistor including a drain connected to a power supply terminal (VDD), and a gate connected to an output terminal; a PMOS transistor including a source connected to a source of the depletion type NMOS transistor, a drain connected to the output terminal, and a gate connected to an input terminal; and an NMOS transistor including a source connected to a reference terminal (GND), a gate connected to the input terminal, and a drain connected to the output terminal.

Abstract: Provided is a convenient mouse device having low power consumption. The mouse device has a configuration in which an optical sensor for light shielding detection is provided in a region where a hand blocks light when the hand handles the mouse device so that the mouse device may perform a normal operation when the optical sensor for light shielding detection is shielded from light, and may perform a low consumption operation when the optical sensor for light shielding detection is not shielded from light.

Abstract: Provided is a constant current circuit capable of supplying a stable constant current. Even when K values of NMOS transistors vary due to manufacturing fluctuations in semiconductor devices, a voltage generated across a resistor is always a threshold voltage difference between the NMOS transistors, and thus hardly varies. Even when the K values of the NMOS transistors vary due to a change in temperature, the voltage generated across the resistor is always the threshold voltage difference between the NMOS transistors, and thus hardly varies.

Abstract: Provided is a boosting circuit having a small circuit scale. When a node (Vg) is reset by a reset transistor (M3) after a boosting operation has been finished, the reset transistor (M3) is controlled based on a power supply voltage to reset the node (Vg). Therefore, another boosted voltage is not required for the reset, and hence an additional boosting circuit required for the another boosted voltage is unnecessary as well. As a result, the circuit scale of the boosting circuit is reduced correspondingly to the additional boosting circuit.

Abstract: Provided is a power-on reset circuit suitable for a semiconductor device that operates at a low supply voltage. When a supply voltage (VDD) becomes higher than a first output circuit reversal threshold voltage (Vz) after a reset signal is output, a first control circuit (51) operates so that the reset signal is not output. With an appropriate circuit design in which the first output circuit reversal threshold voltage (Vz) is low, the output and stop of the reset signal is enabled at the low supply voltage (VDD).

Abstract: Provided is an input circuit having hysteresis characteristics that is capable of operating in a wide range of power supply voltage conditions while suppressing power supply voltage dependence of a hysteresis voltage and a response speed. The input circuit is provided with: a circuit for obtaining a small hysteresis voltage under the condition of low power supply voltage (formed of PMOS transistors (101 to 103) and an inverter (501)); and a circuit for obtaining a large hysteresis voltage under the condition of low power supply voltage (formed of PMOS transistors (101 and 104) and the inverter (501)).

Abstract: Provided is a nonvolatile semiconductor memory device which reads out a memory cell at high speed. A minute current source (105) is connected to a clamp NMOS transistor (103) for clamping a drain voltage of a memory cell (101), and a minute current is caused to flow through the clamp NMOS transistor (103). When the current does not flow through the memory cell (101), by causing the minute current to flow through the clamp NMOS transistor (103), the drain voltage of the memory cell (101) is prevented from rising. A bias voltage (BIAS) to be input to the clamp NMOS transistor (103) can be set high and the drain voltage of the memory cell (101) can also be high, and hence a current value of the memory cell (101) becomes larger and speed of sensing a current of a sense amplifier circuit (104) is improved.

Abstract: Provided is a semiconductor device equipped with a pull-down circuit capable of reducing its area. The pull-down circuit is formed of a depletion type NMOS transistor in which a gate thereof is connected to a ground potential, and an enhancement type NMOS transistor in which a gate and a drain thereof are connected to a source of the depletion type NMOS transistor and a source thereof is connected to the ground potential. An overdrive voltage of the depletion type NMOS transistor is reduced by a threshold voltage of the enhancement type NMOS transistor, whereby a size of the depletion type NMOS transistor can be reduced. Accordingly, an area of the pull-down circuit can be reduced.

Abstract: Provided is a circuit for detecting power supply voltage drop having a small circuit scale. An NMOS transistor (12) generates a source voltage based on a voltage obtained by subtracting an absolute value of a threshold voltage and an overdrive voltage from a power supply voltage with reference to the power supply voltage. An NMOS transistor (17) is turned on/off based on the source voltage of the NMOS transistor (12). A PMOS transistor (15) generates a source voltage based on a voltage obtained by adding an absolute value of a threshold voltage and an overdrive voltage to a ground voltage with reference to the ground voltage. A PMOS transistor (19) is turned on/off based on the source voltage of the PMOS transistor (15).

Abstract: Provided is a complementary metal oxide semiconductor (CMOS) input buffer circuit that is capable of lower voltage operation with lower current consumption. The CMOS input buffer circuit includes: a depletion type NMOS transistor including a drain connected to a power supply terminal (VDD), and a gate connected to an output terminal; a PMOS transistor including a source connected to a source of the depletion type NMOS transistor, a drain connected to the output terminal, and a gate connected to an input terminal; and an NMOS transistor including a source connected to a reference terminal (GND), a gate connected to the input terminal, and a drain connected to the output terminal.

Abstract: Provided is a semiconductor memory device, which realizes characteristic evaluation even in a case where a threshold voltage is a negative potential by a test method which is similar to a case of a positive potential. The semiconductor memory device includes a plurality of memory cells for storing data. When a test signal is input, the semiconductor memory device changes from a normal mode to a test mode for evaluating characteristics of the plurality of memory cells.

Abstract: In a power supply switching circuit, a transistor that switches to a highest voltage is formed of an enhancement type PMOS transistor, and transistors that switch other voltages are each formed of a depletion type NMOS transistor. A signal for controlling a gate of each of the transistors is input through a level shifter. The depletion type NMOS transistor does not operate in a bipolar manner even if a source voltage thereof reaches a power supply voltage VPP1 or VPP2, and the enhancement type PMOS transistor does not operate in the bipolar manner even if a gate voltage and a source voltage thereof reach the power supply voltage VPP1, and a drain voltage thereof reaches the power supply voltage VPP2. Accordingly, there can be provided the power supply voltage switching circuit that is high in efficiency.

Abstract: Provided is a photodetector circuit having significantly low current consumption. The photodetector circuit includes two opposing P-channel metal oxide semiconductor (MOS) transistors each including a gate connected to a drain of the opposing P-channel MOS transistor. The drain of one of the P-channel MOS transistors is discharged with an ON-state current of an N-channel MOS transistor which is turned ON with a voltage generated in a photoelectric element. The drain of the other of the P-channel MOS transistors is discharged with an ON-state current of a depletion type N-channel MOS transistor including a gate to which a voltage of a reference power supply terminal is input, and a source to which the voltage generated in the photoelectric element is input.

Abstract: Provided is a power supply switching circuit capable of efficiently supplying a desired voltage among a plurality of voltages to a load. In the case of a P-type semiconductor substrate, N-type MOS transistors are provided between a load and an AC adapter and between the load and a battery, and hence no parasitic diode exists between the load and the AC adapter or the battery, resulting in no current path due to the parasitic diode. Thus, when the AC adapter and the battery are connected to the power supply switching circuit, the N-type MOS transistor is turned off, whereby the current path between the battery and the load is cut off completely and the N-type MOS transistor is turned on. Accordingly, the battery cannot supply a voltage to the load while only the AC adapter can supply a voltage to the load.

Abstract: Provided is a magnetic sensor circuit capable of a low-voltage operation, which comprises a Hall element and a magnetic offset cancellation circuit for the Hall element. In the magnetic sensor circuit using the Hall element, at the time of turning on transmission gates for switching connections between input terminals of an amplifier circuit in the magnetic offset cancellation circuit and electrodes of the Hall element in order to cancel a magnetic offset of the Hall element, gates of N-channel transistors in the transmission gates are set at voltages higher than a power supply voltage by a drive circuit.

Abstract: Provided is a boosting circuit having a small circuit scale. When a node (Vg) is reset by a reset transistor (M3) after a boosting operation has been finished, the reset transistor (M3) is controlled based on a power supply voltage to reset the node (Vg). Therefore, another boosted voltage is not required for the reset, and hence an additional boosting circuit required for the another boosted voltage is unnecessary as well. As a result, the circuit scale of the boosting circuit is reduced correspondingly to the additional boosting circuit.

Abstract: Provided is a power-on reset circuit suitable for a semiconductor device that operates at a low supply voltage. When a supply voltage (VDD) becomes higher than a first output circuit reversal threshold voltage (Vz) after a reset signal is output, a first control circuit (51) operates so that the reset signal is not output. With an appropriate circuit design in which the first output circuit reversal threshold voltage (Vz) is low, the output and stop of the reset signal is enabled at the low supply voltage (VDD).

Abstract: Provided is an electronic equipment including: a boost DC-DC converter and an electric power storage device, in which the electric power storage device is charged with a electric power outputted the DC-DC converter with efficiency, and in which stored electric power of the electric power storage device is not wastefully consumed even when supply of the electric power is stopped. The electronic equipment including the power supply, the boost DC-DC converter, a rectifier rectifying a pulse-like boosted electric power outputted the DC-DC converter to a second boosted electric power, and the electric power storage device for charging a first boosted electric power from the boost DC-DC converter, wherein an operation of the boost DC-DC converter is maintained by the second boosted electric power.

Abstract: Provided is a nonvolatile semiconductor memory device which reads out a memory cell at high speed. A minute current source (105) is connected to a clamp NMOS transistor (103) for clamping a drain voltage of a memory cell (101), and a minute current is caused to flow through the clamp NMOS transistor (103). When the current does not flow through the memory cell (101), by causing the minute current to flow through the clamp NMOS transistor (103), the drain voltage of the memory cell (101) is prevented from rising. A bias voltage (BIAS) to be input to the clamp NMOS transistor (103) can be set high and the drain voltage of the memory cell (101) can also be high, and hence a current value of the memory cell (101) becomes larger and speed of sensing a current of a sense amplifier circuit (104) is improved.

Abstract: Provided is a constant current circuit capable of supplying a stable constant current. Even when K values of NMOS transistors vary due to manufacturing fluctuations in semiconductor devices, a voltage generated across a resistor is always a threshold voltage difference between the NMOS transistors, and thus hardly varies. Even when the K values of the NMOS transistors vary due to a change in temperature, the voltage generated across the resistor is always the threshold voltage difference between the NMOS transistors, and thus hardly varies.