A voltage-controlled oscillator gain measurement system includes a voltage-controlled oscillator, a voltage detector, and a processor. The voltage-controlled oscillator, which is configured in a phase-locked loop circuit, generates an output signal with an output frequency according to a control signal. The control signal is generated according to the output signal divided by a scaling number. The voltage detector is configured to measure a voltage difference of the control signal. The processor adjusts the scaling number to generate an output frequency difference of the output signal, and obtains a reciprocal gain of the voltage-controlled oscillator by dividing the voltage difference by the output frequency difference.

A current measurement device comprising: a shunt resistor; a pair of first and second voltage signal lines connected to the shunt resistor; and a current measurement circuit for measuring a current using a signal by the pair of first and second voltage signal lines. The pair of first and second voltage signal lines are connected to an amplifier circuit with which the current measurement circuit is provided to amplify a voltage signal. A third signal line which is a signal line different from the pair of first and second voltage signal lines and drawn from the shunt resistor is connected to a common line of the current measurement circuit.

Provided is an electrostatic capacitance sensor which can remove an influence of a noise occurring from a static eliminator or a driving source and accurately perform measurement even on electrostatic capacitance detected by a thin-type detection unit which can be passed to a finger surface of a wafer transfer robot. The present invention is provided with an AC supply source which supplies an AC voltage to a detection unit, a parasitic capacitance compensation circuit, an operational amplifier, a differential amplifier, a phase detection means, and a low pass filter. An operational amplification output terminal is connected to an inversion input terminal of the differential amplifier through a first band pass filter, the AC supply source is connected to a non-inversion input terminal of the differential amplifier through a second band pass filter, an output terminal of the differential amplifier is connected to an input terminal of the phase detection means, and the phase detection means takes, as a reference signal, an AC signal output from the AC supply source.

In one implementation, a circuit can include a reference pin and an operational amplifier that can include an output pin, an inverting input pin and a non-inverting input pin. The inverting input pin can be electrically coupled to the output pin via a first impedance and to the reference pin via a second impedance. The non-inverting input pin can be electrically coupled to the reference pin via a third impedance and can be configured to receive a detection signal. The reference pin can be configured to receive a detection reference signal associated with the detection signal.

To provide a current detection circuit capable of suppressing the occurrence of a large potential difference between input terminals of a differential amplifier circuit, and preventing degradation of input transistors. A differential amplifier circuit is equipped with a clamp circuit which limits gate-source voltages of a pair of PMOS transistors each having a bulk and a source connected to each other with the sources of the pair of PMOS transistors as input terminals.

An apparatus for measuring a device current of a device under test (DUT) includes a first circuit including a first terminal for coupling to a first connection terminal of the DUT. The first circuit is configured to supply a first test voltage for the first terminal and to output a first output voltage sensed at the first terminal. The apparatus further includes a second circuit having a second terminal for coupling to a second connection terminal of the DUT. The second circuit is configured to supply a second test voltage for the second terminal and to output a second output voltage sensed at the second terminal. The apparatus further includes a third circuit configured to determine the device current of the DUT based on the first output voltage, the second output voltage, the first test voltage and the second test voltage. The first circuit and the second circuit are identical.

An apparatus, method and integrated circuit for broad-range current measurement using variable resistance are disclosed. Embodiments of an apparatus for sensing current through a transistor device may include an interface configured to receive a current from the transistor device for sensing. In an embodiment, the apparatus may also include a sensor component coupled to the interface and configured to receive the current from the transistor device and to generate a responsive sensor voltage, the sensor component comprising an adjustable resistance component, a resistance value of the adjustable resistance component being selectable in response to a level of the current received at the interface.

An autoranging ammeter with fast dynamic response allows improved dynamic measurement of rapidly changing direct electrical currents. The ammeter utilizes a low-cost dual threshold comparator mechanism coupled with an analog-to-digital converter and digital processing to rapidly select the appropriate current shunt resistor.

A current sensing circuit includes a current detection unit having a first resistance element; a first MOS-transistor and a first constant current source connected between a first output end of the current detection unit and a ground terminal; a second MOS-transistor and a second constant current source connected between a second output end of the current detection unit and the ground terminal; a third MOS-transistor having a source connected to the first output end and a gate connected to a drain of the second MOS-transistor; a second resistance element connected between an output terminal and the ground terminal; and a high withstand-voltage MOS-transistor connected between the third MOS-transistor and the output terminal to receive a predetermined control voltage, wherein the gates of the first and second MOS-transistors are commonly connected, and the gate of the first MOS-transistor is connected to the drain thereof.

An input circuitry for receiving electrode signals comprises: a plurality of channels for providing a multiplexed electrode signal input, each channel comprising a multiplexing switch for selecting one channel at a time, and an input transistor configured to be connected to an electrode, wherein the input transistor is configured to receive an electrode signal at a gate; and a reference input transistor, which is configured to be connected to a reference voltage at a gate; wherein an electrode signal received at a selected channel together with the reference voltage form input signals to an instrumentation amplifier; wherein the input circuitry is configured such that the input transistor of the selected channel forms part of a first flipped voltage follower and the reference input transistor forms part of a second flipped voltage follower.