A current measurement and control circuit may comprise a shunt resistor coupled between supply and output nodes; a first resistor coupled to the supply node; a second resistor coupled to ground; and a transconductance amplifier having an input coupled to the first resistor to define a compensation node and another input coupled to the output node. The circuit may also include a first transistor having a first current terminal coupled to the compensation node and a second current terminal coupled to the second resistor to define a measurement node; and a second transistor having a first current terminal coupled to ground and a second current terminal coupled to the output node. The circuit may also include an ADC having an analog input coupled to the measurement node; an IDAC having an analog output coupled to the compensation node; and switches to set the circuit in a measurement or a compensation mode.

A current measurement and control circuit may comprise a shunt resistor coupled between supply and output nodes; a first resistor coupled to the supply node; a second resistor coupled to ground; and a transconductance amplifier having an input coupled to the first resistor to define a compensation node and another input coupled to the output node. The circuit may also include a first transistor having a first current terminal coupled to the compensation node and a second current terminal coupled to the second resistor to define a measurement node; and a second transistor having a first current terminal coupled to ground and a second current terminal coupled to the output node. The circuit may also include an ADC having an analog input coupled to the measurement node; an IDAC having an analog output coupled to the compensation node; and switches to set the circuit in a measurement or a compensation mode.

The disclosure relates to a measuring device for measuring a physical variable. The measuring device has a converter, which is designed to convert an input variable present at a measurement input, into a measurement signal and to provide the same as an output variable. The measuring device comprises a processing unit, which is configured to process the output variable of the converter, and a signal generator, which is designed to generate a test signal on the basis of a specification which test signal corresponds to an output variable of the converter to an input variable of the converter corresponding to the specification. The processing unit can be connected via a switching element either to an output of the converter or to an output of the signal generator. The disclosure further relates to a method for testing a measuring device.

The disclosure relates to a measuring device for measuring a physical variable. The measuring device has a converter, which is designed to convert an input variable present at a measurement input, into a measurement signal and to provide the same as an output variable. The measuring device comprises a processing unit, which is configured to process the output variable of the converter, and a signal generator, which is designed to generate a test signal on the basis of a specification which test signal corresponds to an output variable of the converter to an input variable of the converter corresponding to the specification. The processing unit can be connected via a switching element either to an output of the converter or to an output of the signal generator. The disclosure further relates to a method for testing a measuring device.

A terminal block for current measurement in a power grid. The terminal block includes a shunt and a temperature sensor, and is configured to be connected to an Intelligent Electronic Device IED and a primary device. Furthermore, a respective IED and a system for current measurement including the IED and the terminal block are disclosed as well as a method for calibration of the system and a method for current measurement in power grids. A voltage measurement unit in the IED is adapted to measure a voltage drop at the shunt; a current flowing through the shunt can be calculated from the temperature and from calibration data. The terminal block enables a particularly efficient calibration method.

A terminal block for current measurement in a power grid. The terminal block includes a shunt and a temperature sensor, and is configured to be connected to an Intelligent Electronic Device IED and a primary device. Furthermore, a respective IED and a system for current measurement including the IED and the terminal block are disclosed as well as a method for calibration of the system and a method for current measurement in power grids. A voltage measurement unit in the IED is adapted to measure a voltage drop at the shunt; a current flowing through the shunt can be calculated from the temperature and from calibration data. The terminal block enables a particularly efficient calibration method.

The present invention provides a voltage acquisition circuit. The voltage acquisition circuit includes a voltage division and sampling module, a voltage to frequency conversion module, and an isolation module. The voltage to frequency conversion module is electrically coupled to the voltage division and sampling module and the isolation module. The voltage division and sampling module is configured to divide and sample a total voltage of a battery pack, and output a voltage signal to the voltage to frequency conversion module. The voltage to frequency conversion module is configured to convert the voltage signal into a first frequency signal, and output the first frequency signal to the isolation module. The isolation module is configured to electrically isolate the first frequency signal, to generate a second frequency signal. The present invention further provides an electric vehicle with the voltage acquisition circuit.

The present invention provides a voltage acquisition circuit. The voltage acquisition circuit includes a voltage division and sampling module, a voltage to frequency conversion module, and an isolation module. The voltage to frequency conversion module is electrically coupled to the voltage division and sampling module and the isolation module. The voltage division and sampling module is configured to divide and sample a total voltage of a battery pack, and output a voltage signal to the voltage to frequency conversion module. The voltage to frequency conversion module is configured to convert the voltage signal into a first frequency signal, and output the first frequency signal to the isolation module. The isolation module is configured to electrically isolate the first frequency signal, to generate a second frequency signal. The present invention further provides an electric vehicle with the voltage acquisition circuit.

Aspects of the disclosure are directed to voltage-based current sensing. In accordance with one aspect, voltage-based current sensing may include performing a coarse calibration of a voltage based current sensor to determine a coarse offset; performing a fine calibration of the voltage based current sensor to determine a fine offset; performing a frequency calibration of the voltage based current sensor to determine a frequency offset; and performing a transfer function calibration of the voltage based current sensor to determine a sensor transfer function using one or more of the coarse offset, the fine offset and the frequency offset; and measuring a load current using the sensor transfer function.

A system and method are provided for compensating for thermal drift of a probe device. The method includes monitoring a first temperature of a laser source in a sensor head that receives output electrical signals from a DUT and outputs corresponding optical signals; monitoring a second temperature of a photoreceiver in a probe interface that converts the optical signals to electrical test signals to input to the test instrument; calculating a first value of a first bias voltage using the first temperature; applying the first value of the first bias voltage to the laser source to compensate for thermal drift when the first temperature is within a first predefined temperature range; calculating a second value of a second bias voltage for the photoreceiver using the second temperature; and applying the second value of the second bias voltage to the photoreceiver to compensate for thermal drift when the second temperature is within a second predefined temperature range.