Inductive load driving circuit
AssigneeRohm Co., Ltd.
InventorSeiichi Yamamoto
Life of this patent
Estimating the term…
Abstract
A circuit has first and second switching transistors that are connected between a power supply potential point and ground potential point GND, and controllably turned on and off to drive an inductive load. The circuit is provided with an N-type guardring 27 that prevents effects on other elements formed on the same semiconductor substrate, and the guardring connects to the ground potential point GND. By this structure, a load current in an inverse direction can be flown by a parasitic diode of the switching transistor that is provided on the side of a ground and is in an off state. Also, the operation of a parasitic diode Tr generated in this instance is restrained and the power loss is reduced.
Claims8
An inductive load driving circuit formed in an integrated circuit device, the inductive load driving circuit comprising:
- a first switching transistor connected between a first power supply potential point (Vcc) and a first output terminal;
- a second switching transistor connected between the first power supply potential point (Vcc) and a second output terminal;
- a third switching transistor connected between the first output terminal and a second power supply potential point (GND);
- a fourth switching transistor connected between the second output terminal and the second power supply potential point (GND), wherein
- one of the third switching transistor and the fourth switching transistor is turned on or off depending on a power supply direction in which power is supplied to a load, and the first switching transistor or the second switching transistor is controllably turned on and off, to thereby supply an adjusted power in a forward direction or in an inverse direction to an inductive load that is connected between the first output terminal and the second output terminal;
- and
- a guardring of an N-type semiconductor region provided for the third switching transistor and/or the fourth switching transistor, the guardring being connected to the second power supply potential point (GND).
An inductive load driving circuit formed in an integrated circuit device, the inductive load driving circuit comprising:
- a first switching transistor connected between a first power supply potential point (Vcc) and an output terminal;
- a second switching transistor connected between the output terminal and a second power supply potential point (GND), wherein
- the first switching transistor and the second switching transistor are controllably turned on and off, to thereby supply an adjusted power to an inductive load that is connected between the output terminal and the second power supply potential point (GND);
- and
- a guardring of an N-type semiconductor region is provided for the second switching transistor, the guardring being connected to the second power supply potential point (GND).
Dependencies are inferred from the claim text.