Updated: Active OR controller powers up to 400V

Diode’s ZXGD3112N7 active ORing mosfet controller supports redundancy power systems with rail voltages up to 400V.

Diodes ZXGD3112 - Active OR controller powers up to 400V

The chip controls an n-channel mosfet so that the mosfet behaves like a low-drop diode “providing a highly efficient power system that is well-suited for target applications in telecoms systems, data centres and servers, where OR’ing two or more power supplies together provides redundancy,” said the firm.

Dropping less than a diode also cuts local power dissipation.

The turn‑off threshold voltage of <5mV is claimed to improve light-load stability, and the controller can implement turn off in <600ns to cut reveres current flow – 5A sink current is available to discharge of the gate, or the gates of paralleled mosfets.

Diodes ZXGD3112The chip will work with mosfets in either the positive or negative rail.

The chip works from voltages up to 20V, and only the mosfet drain connection pin is 400V capable, which means one or more auxilary supplies are needed in applications with rails over 20V – to create +10V relative to the switched rail, in both positive and negative rail switching.

No auxiliary supply is needed with negative rail ORing up to 20V.

The device comes in a SO-7 – an SO-8 with a pin removed to increase voltage isolation for the high-voltage drain pin.


Electronics Weekly had spotted something odd in the data sheet, which has now been corrected. DS37739 rev2-2 is the one you want, rev1-2 had errors in the auxiliary supply for one of the OR-ing application examples.

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