TIPD102

This verified design delivers a well-regulated current to a ground-referenced load that could be used for actuators, sensors, motors, and many other applications. The design utilizes a two-stage approach to allow the high-side current source to accept a ground-referenced input. The first stage uses an op amp and n-channel MOSFET to translate the ground-referenced input to a supply-referenced signal. The supply-referenced signal drives the second stage op amp that controls the gate of a p-channel MOSFET to regulate the load current. The OPA2333 is used for both stages of the design because of the low quiescent current, rail-to-rail input/output, and zero-drift chopper technology. The rail-to-rail input stage includes voltages that exceed both supply rails so there is no loss or "dead-zone" when used as a low-side sink for the first stage or as a high-side source for the second stage. The rail-to-rail output ensures that the op amp is able to successfully turn off the active devices ensuring low zero-scale currents. The zero-drift architecture allows for precision DC performance over temperature.

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