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0-70 to 4-20mA circuit with startup problems
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lmagalhaes:
Hey there,
I saw a circuit online to convert a 0-10V signal to 4-20mA current signal and I adapted it to 0-70V. The problem is that sometimes, when the circuit is connected to the 24V power rail, the output of the ampops is completly wrong. Either it locks to a certain value (like 7mA, 20mA or 0mA) or it starts on an arbitrary value and then goes from there. Here's the schematic:
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I feel that the problem is with the TLV2186. It says that the maximum supply voltage is 24V with an absolute maximum of 26V. Maybe on the startup there's some spikes that go over that and it doesn't work that well ? I have placed caps on C2 and C3, 500pF. They helped with the consistency and turned the signals between the opamps DC, but the startup problem remained. I also tried to add a 100nF decoupling cap on the supply pin of the TLV2186 but still nothing. Have I missed something obvious ?
Thanks
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