Abstract: A successive approximation A/D conversion circuit for simultaneously sampling N channels of analog signals and for A/D converting the sampled analog signals, includes: N capacitive main DACs; a resistive sub DAC; N comparators; and a successive approximation control circuit, wherein the successive approximation control circuit determines high-order bit values of A/D conversion results of the N channels of analog signals by controlling the N capacitive main DACs and the N comparators, and determines low-order bit values of the A/D conversion results of the N channels of analog signals by controlling the resistive sub DAC and the N comparators.

Abstract: The present invention is contrived to adopt a differential pair type amplifier circuit comprising a differential pair constituted by a first transistor receiving an input of a first signal and by a second transistor receiving an input of a third signal generated by outputting a second signal of which the voltage level is a power supply voltage. Elements requiring a matching are two transistors constituting the differential pair for the amplifier circuit. Because of this, the elements requiring a matching can be placed close to each other regardless of a layout between the amplifier circuits.

Abstract: An analog circuit cell array includes a plurality of transistor cell arranged in an array. Each of the transistor cells includes a first source region, a first channel region, a common drain region, a second channel region, and a second source region arranged in sequence one adjacent to another; and a first gate electrode and a second gate electrode formed on the first channel region and the second channel region, respectively, and wherein the first gate electrode and the second gate electrode are connected together for use, and the first source region and the second source region are connected together for use.

Abstract: A successive approximation A/D converter includes a capacitive D/A converter including capacitors, and generates a voltage based on the input voltage and a first digital signal including J bits; a resistive D/A converter that generates a voltage based on a second digital signal; a capacitor that capacity-couples the voltage to an output node; a comparator that generates a result based on the voltage; a control circuit that supplies the first digital signal to the capacitive D/A converter according to the result and outputs a third digital signal indicating a correction and a fourth digital signal including K bits; and a digital calculating circuit that generates the second digital signal including K bits based on the third digital signal and the fourth digital signal, and supplies the second digital signal to the resistive D/A converter, a (J+K) bit digital data is generated based on the input signal.

Abstract: A successive approximation type AD converter circuit for comparing an analog input signal with an output analog signal of a DA converter with a comparator to input a digital signal output in accordance with a comparison result to the DA converter to determine a digital signal obtained if the output analog signal of the DA converter is equal to the analog input signal, as an AD-converted output signal, includes: an AD converter for AD-converting the analog input circuit in accordance with a sampling period for sampling the analog input signal and a comparison period for comparing the sampled analog input signal with the output analog signal of the DA converter with the comparator; and setting means for independently setting a cycle time of a first clock signal for determining the sampling period and a cycle time of a second clock signal for determining the comparison period.

Abstract: The present invention is contrived to adopt a differential pair type amplifier circuit comprising a differential pair constituted by a first transistor receiving an input of a first signal and by a second transistor receiving an input of a third signal generated by outputting a second signal of which the voltage level is a power supply voltage. Elements requiring a matching are two transistors constituting the differential pair for the amplifier circuit. Because of this, the elements requiring a matching can be placed close to each other regardless of a layout between the amplifier circuits.

Abstract: A successive approximation type AD converter circuit for comparing an analog input signal with an output analog signal of a DA converter with a comparator to input a digital signal output in accordance with a comparison result to the DA converter to determine a digital signal obtained if the output analog signal of the DA converter is equal to the analog input signal, as an AD-converted output signal, includes: an AD converter for AD-converting the analog input circuit in accordance with a sampling period for sampling the analog input signal and a comparison period for comparing the sampled analog input signal with the output analog signal of the DA converter with the comparator; and setting means for independently setting a cycle time of a first clock signal for determining the sampling period and a cycle time of a second clock signal for determining the comparison period.

Abstract: A level conversion circuit that prevents the operation speed from decreasing when the power supply voltage decreases while appropriately performing level conversion. The level conversion circuit includes first and second PMOS transistors. A first NMOS transistor is connected to the first PMOS transistor and the second PMOS transistor. A second NMOS transistor is connected to the second PMOS transistor and the first PMOS transistor. A bias circuit, connected to the first and second NMOS transistors, generates a bias potential that is supplied to the first and second NMOS transistors and that is greater than the first voltage by a threshold voltage of the first and second NMOS transistors. The bias circuit further controls current, which determines the bias potential and flows to the bias circuit, in accordance with a control signal having the first voltage.

Abstract: A reference voltage generation circuit has transistors generating a PTAT current that increases in proportion to temperature, a transistor generating a CTAT current that decreases in proportion to temperature, a first variable resistor adjusting an output voltage, a transistor supplying the PTAT current to the first variable resistor via a first switch, a transistor supplying the CTAT current to the first variable resistor via a second switch, and a second variable resistor adjusting the CTAT current. The first switch is on in first and third operation modes and off in a second operation mode. The second switch is on in the first and second operation modes and off in the third operation mode. Switching the operation modes realizes independently outputting a PTAT voltage or a CTAT voltage. Independently adjusting the voltages makes it possible to correct output reference voltage of the reference voltage generation circuit accurately at low cost.

Abstract: The present invention is contrived to adopt a differential pair type amplifier circuit comprising a differential pair constituted by a first transistor receiving an input of a first signal and by a second transistor receiving an input of a third signal generated by outputting a second signal of which the voltage level is a power supply voltage. Elements requiring a matching are two transistors constituting the differential pair for the amplifier circuit. Because of this, the elements requiring a matching can be placed close to each other regardless of a layout between the amplifier circuits.

Abstract: A reference voltage generation circuit has transistors generating a PTAT current that increases in proportion to temperature, a transistor generating a CTAT current that decreases in proportion to temperature, a first variable resistor adjusting an output voltage, a transistor supplying the PTAT current to the first variable resistor via a first switch, a transistor supplying the CTAT current to the first variable resistor via a second switch, and a second variable resistor adjusting the CTAT current. The first switch is on in first and third operation modes and off in a second operation mode. The second switch is on in the first and second operation modes and off in the third operation mode. Switching the operation modes realizes independently outputting a PTAT voltage or a CTAT voltage. Independently adjusting the voltages makes it possible to correct output reference voltage of the reference voltage generation circuit accurately at low cost.

Abstract: A band gap circuit includes a voltage generating circuit, and a first and a second switched capacitor circuits (SCC). Operational amplifier in the first and the second SCC are connected though a coupling capacitor. Capacitance of the coupling capacitor is smaller than that of a feedback capacitor in the first SCC. A PTAT voltage is obtained by multiplying a thermal voltage by a coefficient determined based on capacitances of input capacitors and feedback capacitors in each of the first and the second SCC, and the coupling capacitor. The voltage generating circuit generates a forward bias voltage that has a negative temperature-dependency at a p-n junction. The PTAT voltage is added to the forward bias voltage to generate a reference voltage independent of temperature.

Abstract: Included are a first unit including a DAC which generates a comparison signal serving as an object of comparison with the first analog signal, taking in and retaining the first analog signal, a second unit including a DAC which generates a comparison signal serving as an object of comparison with the first analog signal, taking in and retaining the second analog signal, a first switch connecting the first unit to an output side of the second unit, a comparator comparing a differential value between the first analog signal and the second analog signal with a differential value between the comparison signal of the first DAC and an output signal of the second DAC, and an electric potential control circuit controlling fluctuations in electric potentials of the first analog terminal and the second analog terminal.

Abstract: A level conversion circuit that prevents the operation speed from decreasing when the power supply voltage decreases while appropriately performing level conversion. The level conversion circuit includes first and second PMOS transistors. A first NMOS transistor is connected to the first PMOS transistor and the second PMOS transistor. A second NMOS transistor is connected to the second PMOS transistor and the first PMOS transistor. A bias circuit, connected to the first and second NMOS transistors, generates a bias potential that is supplied to the first and second NMOS transistors and that is greater than the first voltage by a threshold voltage of the first and second NMOS transistors. The bias circuit further controls current, which determines the bias potential and flows to the bias circuit, in accordance with a control signal having the first voltage.

Abstract: Included are a first DAC taking in and retaining sample data of a first analog signal and generating a comparison signal serving as an object of comparison with the first analog signal, a second DAC taking in and retaining sample data of a second analog signal and generating a comparison signal as an object of comparison with the second analog signal, a first switch connecting the first digital-to-analog converter to an output side of a second digital converter in a openable/closable manner, a comparator comparing, when the first switch is opened, a differential value between the first analog signal and the second analog signal with a differential value between an output signal of the first DAC and an output signal of the second DAC, and an electric potential control circuit controlling fluctuations in electric potentials of a first analog terminal and a second analog terminal.

Abstract: A successive approximation A/D converter includes a sample-hold amplifier circuit configured to sample and hold an input analog voltage to produce an internal analog voltage proportional to the input analog voltage with a voltage gain being smaller than 1, a switched capacitor D/A converter coupled to the sample-hold amplifier circuit and including a plurality of capacitors for storing electric charge responsive to the internal analog voltage, the switched capacitor D/A converter configured to switch couplings of the capacitors in response to a control signal to produce a comparison analog voltage responsive to the internal analog voltage and the control signal, a comparator coupled to the switched capacitor D/A converter to produce a comparison result signal responsive to the comparison analog voltage, and a control circuit coupled to the comparator to supply the control signal responsive to the comparison result signal to the switched capacitor D/A converter.

Abstract: A semiconductor device in which a dielectric breakdown of a gate oxide in a MOS capacitor can be prevented and in which a circuit area can be reduced. The semiconductor device comprises an NMOS transistor a gate of which is connected to a terminal VDD on a high potential side and a PMOS transistor a gate of which is connected to a terminal GND on a low potential side, source/drain (S/D) regions of the NMOS transistor and source/drain (S/D) regions of the PMOS transistor being electrically connected.

Abstract: A band gap circuit includes a voltage generating circuit, and a first and a second switched capacitor circuits (SCC). Operational amplifier in the first and the second SCC are connected though a coupling capacitor. Capacitance of the coupling capacitor is smaller than that of a feedback capacitor in the first SCC. A PTAT voltage is obtained by multiplying a thermal voltage by a coefficient determined based on capacitances of input capacitors and feedback capacitors in each of the first and the second SCC, and the coupling capacitor. The voltage generating circuit generates a forward bias voltage that has a negative temperature-dependency at a p-n junction. The PTAT voltage is added to the forward bias voltage to generate a reference voltage independent of temperature.

Abstract: A successive approximation. A/D converter includes a sample-hold amplifier circuit configured to sample and hold an input analog voltage to produce an internal analog voltage proportional to the input analog voltage with a voltage gain being smaller than 1, a switched capacitor D/A converter coupled to the sample-hold amplifier circuit and including a plurality of capacitors for storing electric charge responsive to the internal analog voltage, the switched capacitor D/A converter configured to switch couplings of the capacitors in response to a control signal to produce a comparison analog voltage responsive to the internal analog voltage and the control signal, a comparator coupled to the switched capacitor D/A converter to produce a comparison result signal responsive to the comparison analog voltage, and a control circuit coupled to the comparator to supply the control signal responsive to the comparison result signal to the switched capacitor D/A converter.

Abstract: A level conversion circuit that prevents the operation speed from decreasing when the power supply voltage decreases while appropriately performing level conversion. The level conversion circuit includes first and second PMOS transistors. A first NMOS transistor is connected to the first PMOS transistor and the second PMOS transistor. A second NMOS transistor is connected to the second PMOS transistor and the first PMOS transistor. A bias circuit, connected to the first and second NMOS transistors, generates a bias potential that is supplied to the first and second NMOS transistors and that is greater than the first voltage by a threshold voltage of the first and second NMOS transistors. The bias circuit further controls current, which determines the bias potential and flows to the bias circuit, in accordance with a control signal having the first voltage.