In a project I am about to do, I need to sense current 1mA-200mA in both positive and negative directions. I searched the forum for a while and didn't find a good lead. I would like to find an IC that simply does that. Can someone give me a suggestion? Thanks.
The Allegro ACS series of current sensors (e.g., ACS712) can sense bidirectional current and are isolated but I'm not sure they're sensitive enough to go down to 200mA. You might want to use two ZXCT1009 (or similar) sensors in parallel, one sensing in one direction the other sensing in the opposite direction. I believe the ZXCT1009 datasheet (or perhaps one of its variants) shows an example circuit of how to do this.
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Yep, the smallest ACS712 is a +-5A so it would not be good for your app.
Rob
Thanks RuggedCircuits and Graynomad. I am not very serious on accuracy so if I use internal 1V reference and 1ohm resistor to sense current via voltage, I should get a 1mA accuracy, maybe good enough if I play with light bulbs with say 50ohm resistance. I'll be off by 2%. I will give it a try first.