Circuit and Method for De-Energizing a Field Coil

A circuit comprising:

• a first switch coupled between a first supply voltage node and a first terminal of an inductance;
• a first diode coupled between the first terminal of the inductance and a reference voltage node;
• a second diode coupled between a second supply voltage node and a second terminal of the inductance, wherein the second supply voltage node is configured to carry a higher voltage than the first supply voltage node;
• and
• a second switch coupled between the second terminal of the inductance and the reference voltage node.

A circuit comprising:

• a load dump detector coupled to a load of a generator;
• and
• a first circuit configured to:
• supply current to a field coil of a generator from a circuit node providing a first substantially constant supply potential via the field coil to a terminal providing a substantially constant reference potential during a normal operation, and
• stop supplying current to the field coil and providing a current path from the terminal providing the constant reference potential via the field coil to a node providing a second constant potential that is higher than the first constant supply potential when a load dump is detected by the load dump detector.

A method of operating a circuit having a first switch coupled between a first supply voltage node and a first terminal of an inductance, a first diode coupled between the first terminal of the inductance and a reference voltage node, a second diode coupled between a second supply voltage node and a second terminal of the inductance, and a second switch coupled between the second terminal of the inductance and the reference voltage node wherein the second supply voltage node is configured to carry a higher voltage than the first supply voltage node;

• and
• providing a first supply voltage to the first supply voltage node;
• and
• providing a second supply voltage to second supply voltage node, wherein the second supply voltage is higher than the first supply voltage.