NJU7890, High Voltage Monitor with Difference Amplifier from New Japan Radio (NJR)
NJU7890 for analog high voltage signal pre-processing in industrial and automotive applications
The NJU7890 integrates two operational amplifiers (OpAmp).
The main amplifier (*1) is a high voltage attenuating difference amplifier. Depending on the device variant the attenuation rate is typically 1/205 (Version A) or 1/311 (Version B). While these kind of amplifiers do NOT feature galvanic isolation they have a very high impedance voltage divider in front of the actual OpAmp. In case of NJU7890 the resistance in the input lines is in the range of 30 MΩ. With this internal resistor circuit the NJU7890 can scale down input signals of some hundred volts to the supply voltage level of 2.2 V to 5.5 V. The common voltage range is 1000 V and the differential voltage range is +/- 1000 V.
The auxillary amplifier (*2) is for universal usage. The power supply is common to both amplifiers. Its inputs and the output are connected to pins of the IC. For example, when wired as comparator the auxillary OpAmp can be used to detect overvoltage conditions.
NJU7890 is housed in package PMAP11-PM which fulfills requirements for creepage distance according to IEC/EN60664.
Typical applications are measurements of high DC-Link voltages that can be found in
- Traction inverters
- High Power Chargers (HPC)
- Battery management systems (BMS)
- Solar power inverters
- Frequency converters
The NJU7890YPM-A-Z with attenuation rate of 1/205 is qualified to AEC-Q100 Grade 1.
Last change: 20210311