A current sensor is for determining the level of the current of a conductor of a low-voltage circuit. In an embodiment, it includes a current transformer including a magnetic core. The magnetic core is an annular core having a core inner diameter, a middle diameter and a core outer diameter. The annular core is wound with a secondary winding, including an inner opening with an inner diameter and an outer circumference with an outer diameter. The secondary winding supplies the circuit with electrical energy. The wound annular core is configured such that the difference between the middle diameter as the minuend and the inner diameter as the subtrahend is 0.5 to 0.6 times smaller than the difference between the outer diameter as the minuend and the inner diameter as the subtrahend, to achieve an optimum for supplying energy and determining the level of the current in connection with the circuit.

A resistance measuring device includes an amplifying unit including an amplifier, a first and a second current supply unit, a voltage detection unit, and a controller. The controller controls the voltage detection unit to detect a first output voltage of an output terminal of the amplifier in a state where the current of the first current source flows in a forward direction to a measurement target resistor by controlling the first current supply unit, controls the voltage detection unit to detect a second output voltage of the output terminal of the amplifier in a state where the current of the second current source flows in a reverse direction to the measurement target resistor by controlling the second current supply unit, and calculates a resistance value of the measurement target resistor based on the detected first output voltage and the detected second output voltage.

Methods and apparatus for measuring current are provided. In one arrangement, a first charge amplifier integrates a current to be measured. A processing circuit filters an output from the first charge amplifier using a first low pass filter module and a second low pass filter module. A second charge amplifier integrates a current derived from the filtered output from the first charge amplifier. The apparatus is configured to reset the first charge amplifier at the start of each of a plurality of sensing frames. The processing circuit obtains at least a first sample of the output from the first charge amplifier in each sensing frame. The sampling of the first sample alternates from one sensing frame to the next sensing frame between sampling via the first low pass filter module and sampling via the second low pass filter module.

A shunt resistor 10, 110 includes a flat resistive element 11; a first electrode block 12 that is made of a conductive metal material and is laminated on a lower surface 11a of the resistive element 11; and a second electrode block 13, 113 that is made of a conductive metal material and is laminated on an upper surface 11b of the resistive element 11, in which the second electrode block 13, 113 is a block body including an electrode portion 14 connected to the resistive element 11 and an extension portion 15, 115 extending downward from a side surface of the electrode portion 14.

A current sensor circuit comprises multiple resistive circuit elements of different values of electrical resistance arranged between at least one input terminal of the current sensor circuit and an output terminal; a first plurality of switching circuits coupled between the input terminal and the resistive circuit elements, wherein each switching circuit of the first plurality of switching circuits includes a pair of transistors connected in series; at least one drive amplifier including an output and an input connected to the output terminal; and a second plurality of switching circuits, each switching circuit including a first switch terminal coupled to the at least one drive amplifier output and a second switch terminal coupled to a common connection of a pair of transistors of the first plurality of switching circuits.

Embodiments of the disclosure provide a method for calibrating a current measurement device, a current measurement method and device, and a display device. The method for calibrating a current measurement device includes: inputting a plurality of given currents to the current measurement device; detecting a plurality of time parameters corresponding to the plurality of given currents; establishing the functional relationship between the current and the time parameter based on the plurality of given currents and the corresponding plurality of time parameters. According to the embodiments of the disclosure, the precision of the current measurement is improved.

A voltage divider circuit arrangement includes a resistive divider circuit portion constructed from first and second resistors (R1, R2) The first and second resistors are connected in series and are arranged to provide a refresh voltage (Vrefresh) at a refresh node between them. A capacitive divider circuit portion is constructed from first and second capacitors (C1, C2). The first and second capacitors are connected in series and are arranged to provide an output voltage (Vout) at an output node. A switching circuit portion is arranged intermittently to switch the voltage divider circuit arrangement between a first mode wherein the resistive divider is enabled and the output node is connected to the refresh node, and a second mode wherein the resistive divider is disabled and the output node is not connected to the refresh node.

A current detection circuit includes an operational amplifier, a current sense amplifier including a first resistor and a second resistor, and a level shifter. The first resistor is provided between one end of a shunt resistor and a first input node of the operational amplifier. The second resistor is provided between the other end of the shunt resistor and a second input node of the operational amplifier. The level shifter controls voltages of the first input node and the second input node by controlling, according to a voltage at the one end of the shunt resistor, currents supplied to the first input node and the second input node.

Load current consumption measured using a first resistor having a high resistive value and a second resistor having a low resistive value. Differential amplifiers, the outputs of which are coupled to analog-to-digital converters and to a processing circuit unit, are connected to each of the nodes of the resistors. Depending on the current level, the processing circuit unit advantageously selects one of the analog-to-digital converters to estimate the present consumption of current in the load. Each input terminal of a resistor is advantageously power supplied from a power amplifier and each power amplifier is advantageously driven by a control loop. For low load currents, the first amplifier associated with the first resistor power supplies the load through the resistors while, for high load currents, when this first amplifier saturates, the second amplifier associated with the second resistor, takes over from the first amplifier to continue to power supply the load.

An insulation monitoring device, according to various embodiment of the present application, comprising an impedance formed between a power line and a ground of a system comprises, a signal generation circuit for applying a triangular wave signal to the power line through a signal measurement circuit, the signal measurement circuit for measuring a voltage difference across the detection resistor of the signal measurement circuit or a current flowing through the detection resistor when the triangular wave signal is applied to the impedance, a control circuit for obtaining an impedance value of the impedance based on at least one of the voltage difference and the current, and monitoring the impedance value.