![]() ![]() If V L1is 600 V and R2 is 10 kW, then the value of R1 is 2990 kW.Ĭhoosing resistors is flexible. Given that the ACPL-C87X’s nominal input voltage for V INis 2 V, a user needs to choose resistor R1 according to Equation 1: High voltage measurement with conversion to an isolated ground referenced output.Ī detailed voltage sensing circuit with the ACPL-C87X is shown in Fig. With an integrated isolation and sensing circuit, the application circuit is significantly simplified compared to alternative solutions that employ separate devices to perform sensing and isolation functions. You can select resistors to form a voltage divider to scale down the voltage signal to be measured to a level within the sensor input range. Using the ACPL-C87X as an isolated voltage sensor is straightforward. The ACPL-C79A family shares the same package and insulation capability as that of the ACPL-C87X family. The ACPL-C87A has unity gain, while the ACPL-C79A is configured with 8.2 times gain. The different input ranges are optimized for voltage sensing and current sensing respectively. The ACPL-C87A accurately measures a 0-2 V input signal, while the ACPL-C79A measures ☒00 mV linear input range. The other differences between the voltage sensor and current senor are input range and gain settings. 1, except that the former is configured as differential inputs (V IN+, and V IN -) instead of a single-ended input (V IN) and shutdown (SHDN). The current sensor ACPL-C79A shares all the key functional blocks of the ACPL-C87A as shown in Fig. ![]() The 1414 V PEAKmaximum working voltage specification per IEC/EN/DIN EN 6 ensures circuits on the low voltage side are not damaged by hazardous high voltages. These iso-amps have a double protection rating of 5000 V RMS/1 min per the UL 1577 safety standard. The ACPL-C87X family features a stretched SO-8 package that is 30% smaller than a DIP-8 package. Other options include ☐.5% (ACPL-C87B) and ☓% (ACPL-C870). The voltage sensor ACPL-C87A provides ☑% measurement accuracy. The output voltage, provided in differential mode for better common mode noise rejection, is proportional to input voltage with unity gain. The photodetector recovers the optical signal and converts it back to an electrical signal, which is decoded and filtered to reproduce an analog output signal. Because the transmitted signal is optical rather than electrical, it is immune to magnetic fields and electrical noise. This optical signal path provides the electrical insulation barrier. The bit stream is then transmitted across the optical coupling pair consisting of an LED and a photodetector. Internal block diagram of the ACPL-C87A.įirst the isolation amplifier senses the input voltage (single-ended analog signal) and converts it to a digital bit stream. Optical Isolation AmplifiersĪs an example, functional blocks of the ACPL-C87A are shown in Fig. These voltage, current and temperature information from the iso-amps are collected by the microcontroller, which uses the data to calculate the feedback values and output signals needed to provide effective control and fault management in the power converters. In this application, the voltage sensor must linearly and accurately measure temperature and send it across the isolation barrier thus providing safety insulation. The isolated voltage sensor ACPL-C87A can also be used in isolated temperature sensing designs. This voltage and current sensing is performed even in the presence of high switching noise. The ACPL-C79A works with a shunt resistor to provide accurate current measurement. 1 (iso-amp) ACPL-C87A works as a precision voltage sensor together with a resistive divider consists of R1 and R2, monitoring the DC bus voltage. With the use of appropriate power switching devices, signal isolators, and control circuits an inverter’s ac output can be set to any required voltage and frequency. Block diagram of power converter in a motor drive. IGBTs form the heart of the inverter they must operate at a high frequency and must be able to withstand high voltages. The inverter converts the dc bus voltage to ac power at a variable frequency to drive the motor. 1 shows a typical inverter in an ac motor drive. Test Saturation Voltage to Achieve High Efficiency #2įig.Test Saturation Voltage to Achieve High Efficiency #1.AC Power Testing Presents Many Challenges and Concerns.EMC Poses Challenge for Automotive Electronics. ![]()
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