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My question is whether I need to regulate the VS input supply (+ and -) prior to feeding it into the Opa548?  My plan was to feed the OPA directly from the rectified A/C (filtered by two 22000uF caps).  In simulations, the output of the rectifier has very low ripple levels even under heavy load, but there is some voltage drop when drawing a lot of current.  My concern is that, since the current limit is referenced to V-, that even slight fluctuations on V- would cause problems.

If pre-regulation is needed, I would put a couple of LM7x15 with power transistors on the input rails to keep VS at a constant regulated state.  This option is just a bit annoying as it would increase board size substantially, due to the space needed for power transistors and the accompanying heat sinks.

Please help.

Thanks!

I didn't find the right solution from the Internet.

References: http://e2e.ti.com/support/amplifiers/etc_amplifiers__other_linear/f/18/p/400424/1417695

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