Abstract: A voltage divider circuit includes: a first voltage divider having first and second capacitors, and an output node configured to output a divider voltage from between the first and second capacitors; a second voltage divider having third and fourth capacitors, and first to third switches, and being connected in parallel to the first voltage divider; and a fourth switch provided between the output node and a connection node of the third and fourth capacitors. In the voltage divider circuit, the switches are controlled based on controlling periods.

Abstract: A voltage divider circuit includes: a first voltage divider having first and second capacitors, and an output node configured to output a divider voltage from between the first and second capacitors; a second voltage divider having third and fourth capacitors, and first to third switches, and being connected in parallel to the first voltage divider; and a fourth switch provided between the output node and a connection node of the third and fourth capacitors. In the voltage divider circuit, the switches are controlled based on controlling periods.

Abstract: A small area oscillator circuit is provided. The oscillator circuit includes first and second constant current sources, a comparator, first and second capacitive elements, and a resistive element. In a first state, the first capacitive element is connected to the first constant current source and the fixed voltage node, the second capacitive element is connected to the second constant current source and the first current source, and resistive element is connected to the second constant current source. In a second state, the first capacitive element is connected to the second constant current source and first constant current source, the second capacitive element is connected to the second constant current source and the fixed voltage node, and the resistive element is connected to the first constant current source.

Abstract: A small area oscillator circuit is provided. The oscillator circuit includes first and second constant current sources, a comparator, first and second capacitive elements, and a resistive element. In a first state, the first capacitive element is connected to the first constant current source and the fixed voltage node, the second capacitive element is connected to the second constant current source and the first current source, and resistive element is connected to the second constant current source. In a second state, the first capacitive element is connected to the second constant current source and first constant current source, the second capacitive element is connected to the second constant current source and the fixed voltage node, and the resistive element is connected to the first constant current source.

Abstract: Increases of circuit scale and power consumption are suppressed while frequency deviation is kept within a predetermined allowable range. A semiconductor device according to an embodiment includes a variable load capacity circuit including a plurality of load capacity elements coupled in parallel to one end of a crystal resonator and a plurality of switches that are respectively serially coupled to the load capacity elements, and a switch control unit that controls ON/OFF of the switches on the basis of information to be an index of frequency deviation due to temperature change of a frequency signal obtained by oscillating the crystal resonator. The switch control unit changes the number of switches that will be turned ON among the plurality of switches so that an absolute value of the frequency deviation becomes small when the information is not included in a predetermined allowable range.

Abstract: A semiconductor device capable of reducing in size thereof and suppressing degradation in the characteristics of circuit components is provided. The semiconductor device includes an LC circuit comprised of a spiral inductor provided over a semiconductor substrate and a capacitive element coupled with the spiral inductor. The spiral inductor includes a central area encircled with a metal wiring and a peripheral area other than the central area. The capacitive element is formed in an upper-layer or a lower-layer position corresponding to the peripheral area other than the central area.

Abstract: To provide a wireless communication module that implements the function to detect a human body in a conserved space and is capable of detecting a proximity to human bodies with high accuracy. A wireless communication module includes an antenna unit and a proximity detector which detects that a human body has approached the module. The antenna unit includes an antenna and a first filter which is comprised of distributed constant elements. The proximity detector for human bodies uses the antenna and the first filter as an electrode to detect capacitance.

Abstract: A differential mixer and a method which can reduce a leak component of a local oscillation differential signal are provided. A differential mixer includes a mixer core unit to which a high frequency signal and a local oscillation differential signal are inputted and which outputs an intermediate frequency differential signal, a common feedback unit which applies a bias voltage to a signal electrically coupled to the high frequency signal and to which a common voltage is fed back from the intermediate frequency differential signal, and a bias unit that applies a reference voltage to the common feedback unit. The common feedback unit generates the bias voltage based on the reference voltage. The bias unit controls the reference voltage so that a leak component of the local oscillation differential signal is a predetermined value or less at an output end of the intermediate frequency differential signal.

Abstract: A semiconductor integrated circuit includes a low-noise amplifier circuit, a transformer, and an ESD protection circuit. The low-noise amplifier circuit amplifies a radio signal that is supplied to an input terminal. The transformer includes a first winding and a second winding and functions as an input impedance matching circuit for the low-noise amplifier circuit, in which at least one end of the second winding is connected to the input terminal of the low-noise amplifier circuit. The ESD protection circuit is connected to a center tap of the first winding.

Abstract: To provide a variable gain amplifier capable of correcting a DC offset voltage through simpler control even when a gain thereof is changed. A differential output type variable gain amplifier is equipped with a first voltage correction unit coupled to a preceding stage of a variable gain amplifier circuit and for outputting a first correction voltage to correct a potential difference generated between a first conductor provided with a first input resistor and a second conductor provided with a second input resistor, and a second voltage correction unit coupled to a subsequent stage of the variable gain amplifier circuit and for correcting a differential output. A control unit is configured to control the first correction voltage and a correction amount of a potential difference by the second voltage correction unit and thereby attenuate a DC offset voltage included in the differential output.

Abstract: A differential mixer and a method which can reduce a leak component of a local oscillation differential signal are provided. A differential mixer includes a mixer core unit to which a high frequency signal and a local oscillation differential signal are inputted and which outputs an intermediate frequency differential signal, a common feedback unit which applies a bias voltage to a signal electrically coupled to the high frequency signal and to which a common voltage is fed back from the intermediate frequency differential signal, and a bias unit that applies a reference voltage to the common feedback unit. The common feedback unit generates the bias voltage based on the reference voltage. The bias unit controls the reference voltage so that a leak component of the local oscillation differential signal is a predetermined value or less at an output end of the intermediate frequency differential signal.

Abstract: A semiconductor device capable of reducing in size thereof and suppressing degradation in the characteristics of circuit components is provided. The semiconductor device includes an LC circuit comprised of a spiral inductor provided over a semiconductor substrate and a capacitive element coupled with the spiral inductor. The spiral inductor includes a central area encircled with a metal wiring and a peripheral area other than the central area. The capacitive element is formed in an upper-layer or a lower-layer position corresponding to the peripheral area other than the central area.

Abstract: A semiconductor integrated circuit includes a transformer that includes a first winding and a second winding, a low-noise amplifier circuit that includes an input terminal in which at least one end of the second winding of the transformer is connected to the input terminal; and a switch that is provided between the one end and another end of the second winding of the transformer. The switch is opened and the transformer functions as an input impedance matching circuit for the low-noise amplifier circuit in a period in which a reception signal is supplied to the first winding of the transformer. On the other hand, the switch is closed and the transformer is caused to become an element including a predetermined capacitance in a period in which another circuit connected to the predetermined node operates.

Abstract: Increases of circuit scale and power consumption are suppressed while frequency deviation is kept within a predetermined allowable range. A semiconductor device according to an embodiment includes a variable load capacity circuit including a plurality of load capacity elements coupled in parallel to one end of a crystal resonator and a plurality of switches that are respectively serially coupled to the load capacity elements, and a switch control unit that controls ON/OFF of the switches on the basis of information to be an index of frequency deviation due to temperature change of a frequency signal obtained by oscillating the crystal resonator. The switch control unit changes the number of switches that will be turned ON among the plurality of switches so that an absolute value of the frequency deviation becomes small when the information is not included in a predetermined allowable range.

Abstract: A semiconductor device (10) includes a transmitting circuit (12) that converts transmission data into a transmission signal with a specified frequency, an amplifier (13) that amplifies a power of the transmission signal, a matching circuit (14) that converts the transmission signal from a balanced signal to an unbalanced signal, and a filter circuit (14) that restricts a frequency band of the transmission signal. The matching circuit includes a primary inductor and a secondary inductor, the filter circuit includes an inductor for a filter, and the primary inductor, the secondary indictor and the inductor for a filter are wound substantially concentrically on one plane.

Abstract: To provide a wireless communication module that implements the function to detect a human body in a conserved space and is capable of detecting a proximity to human bodies with high accuracy. A wireless communication module includes an antenna unit and a proximity detector which detects that a human body has approached the module. The antenna unit includes an antenna and a first filter which is comprised of distributed constant elements. The proximity detector for human bodies uses the antenna and the first filter as an electrode to detect capacitance.

Abstract: A semiconductor integrated circuit includes a low-noise amplifier circuit, a transformer, and an BSD protection circuit. The low-noise amplifier circuit amplifies a radio signal that is supplied to an input terminal. The transformer includes a first winding and a second winding and functions as an input impedance matching circuit for the low-noise amplifier circuit, in which at least one end of the second winding is connected to the input terminal of the low-noise amplifier circuit. The ESP protection circuit is connected to a center tap of the first winding.

Abstract: A semiconductor integrated circuit includes a transformer that includes a first winding and a second winding, a low-noise amplifier circuit that includes an input terminal in which at least one end of the second winding of the transformer is connected to the input terminal; and a switch that is provided between the one end and another end of the second winding of the transformer. The switch is opened and the transformer functions as an input impedance matching circuit for the low-noise amplifier circuit in a period in which a reception signal is supplied to the first winding of the transformer. On the other hand, the switch is closed and the transformer is caused to become an element including a predetermined capacitance in a period in which another circuit connected to the predetermined node operates.

Abstract: To provide a variable gain amplifier capable of correcting a DC offset voltage through simpler control even when a gain thereof is changed. A differential output type variable gain amplifier is equipped with a first voltage correction unit coupled to a preceding stage of a variable gain amplifier circuit and for outputting a first correction voltage to correct a potential difference generated between a first conductor provided with a first input resistor and a second conductor provided with a second input resistor, and a second voltage correction unit coupled to a subsequent stage of the variable gain amplifier circuit and for correcting a differential output. A control unit is configured to control the first correction voltage and a correction amount of a potential difference by the second voltage correction unit and thereby attenuate a DC offset voltage included in the differential output.

Abstract: A semiconductor integrated circuit includes a low-noise amplifier circuit, a transformer, and an ESD protection circuit. The low-noise amplifier circuit amplifies a radio signal that is supplied to an input terminal. The transformer includes a first winding and a second winding and functions as an input impedance matching circuit for the low-noise amplifier circuit, in which at least one end of the second winding is connected to the input terminal of the low-noise amplifier circuit. The ESD protection circuit is connected to a center tap of the first winding.