Every example I have seen for N channel MOSFETS assumes current flows from drain to source when gate voltage is positive relative to the source.
Can current flow from source to drain IF the gate is still positive relative to the source?
Or, would the reverse current simply flow through the devices body diode?
Thanks,
George
Yup.
With the gate positive relative to the source, the fet will look like a real, bidirectional resistor at low s-d voltages. If the drain goes negative more than 0.6 volts or so, the body diode will conduct in parallel with the s-d resistance.
Fets are commonly used in this mode for things like reverse-voltage protection between say a battery and a load. The s-d substrate diode is used like a simple series protection diode, but then cranking in gate voltage shunts current around the diode and reduces voltage drop, getting closer to an ideal diode.
John
Thanks John
That is EXACTLY what I intend on doing.
Ge0rge
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