We design a circuit that AD8479 sense the 400~600V bus for OCP protestion.
when VCC+/- = 0V , The bus = 300V , Does any risk here ?
The part will not provide a proper output, but it should be able to survive that common mode voltage without Vcc at 0V.
I hope this helps!
If bus=300v , At the same time system incharge the VCC e-cap ( 0v to +/- 15V ) . I think should damage ! right ?
As long as the 300V is applied common-mode, it will not damage the part. The AD8479 has large internal resistors so the part actually sees a very small voltage even with a high common-mode voltage applied. It is also built for +/-15V supplies so it should be able to survive.
Could you provide a schematic? Seeing how your circuit is configured will help here.
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