chunyang您好!
多大的稳态共模电压会击穿光耦的初次级呢?是手册中Absolute Maximum Ratings中
Steady-State Input Voltage VIN+,VIN- -2.0 VDD1+0.5 V
这一项吗?如果是这一项那是不是意味着VDD1=5V时,HCPL7840输入信号的单端电压应在-2V~5.5V之间
chunyang您好!
多大的稳态共模电压会击穿光耦的初次级呢?是手册中 Absolute Maximum Ratings 中
Steady-State Input Voltage VIN+,VIN- -2.0 VDD1+0.5 V 这一项吗?
如果是这一项那是不是意味着VDD1=5V时,HCPL7840输入信号的单端电压应在-2V~5.5V之间
谢谢你的点醒!我重新看了下手册里withstand Insulation Test Voltage这个指标是3750Vrms,测试时间是1分钟。里面有如下对CMTI测试的说明
14. CMTI (Common Mode Transient Immunity or CMR, Common Mode Rejection) is tested by applying an exponentially rising/falling voltage step on pin 4 (GND1) with respect to pin 5 (GND2). The rise
time of the test waveform is set to approximately 50 ns. The amplitude of the step is adjusted until the dif erential output (VOUT+ –VOUT-) exhibits more than a 200 mV deviation from the average output
voltage for more than 1μs. The HCPL-7840 will continue to func-tion if more than 10 kV/μs common mode slopes are applied, as long as the breakdown voltage limitations are observed.
那按3750Vrms(1min)这个指标来看,是不是意味着光耦的输入初级如果被加入一个不太大的共模电压,比如500Vrms,光耦还是能够长期稳定正常工作?
谢谢chunyang!我倒是有一个疑问,在电力电子系统中,假如要接收别的机柜传过来的直流模拟量信号,我采用线性光耦隔离的方法接收,线性光耦初级的供电与模拟量并不共地,如果模拟量上叠加有共模干扰,导致VIN+相对于GND1大于了Absolute Maximum Rating中规定的-2V~5.5V的范围,那光耦初级岂不是会击穿?