Clamping Circuit and Method for DMOS Drivers
First Claim
1. In an electrical circuit including an inductive load which has a first side driven by an FET pair including a high side transistor connected in series with a low side transistor between a supply voltage and a reference potential, wherein a second side of said inductive load is connected to a circuit capable of carrying current to a reference potential, and wherein said high side transistor has an associated body diode, a circuit comprising:
- circuitry to operate said high side transistor and said circuit capable of carrying current to selectively allow a current to flow from said supply voltage through said high side transistor, said inductor, and said circuit capable of carrying current; and
a transconductance circuit loop connected to control said circuit capable of carrying current to pull current from said inductive load to said reference potential when said inductive load sources current to said body diode sufficient to cause the voltage across said body diode to exceed a predetermined trip voltage.
1 Assignment
0 Petitions
Accused Products
Abstract
A transconductance circuit (16) and method for protecting an H-bridge power circuit (10) that provides power to a load that includes an inductive component (14) connected between one side of the inductive component (14) and a gate (25) of a low side transistor (24) of the H-bridge (10). The transconductance circuit (16) operates to pull current from the inductive component (14) to ground (30) when the inductive load (14) sources current to a body diode of the high side transistor (20). The transconductance circuit (16) creates a regulated voltage to the gate (25) of the low side transistor (24) to cause the low side transistor (24) to conduct the current away in a regulated manner from the inductor (14) and the high side transistor (20) to ground (30).
68 Citations
20 Claims
-
1. In an electrical circuit including an inductive load which has a first side driven by an FET pair including a high side transistor connected in series with a low side transistor between a supply voltage and a reference potential, wherein a second side of said inductive load is connected to a circuit capable of carrying current to a reference potential, and wherein said high side transistor has an associated body diode, a circuit comprising:
-
circuitry to operate said high side transistor and said circuit capable of carrying current to selectively allow a current to flow from said supply voltage through said high side transistor, said inductor, and said circuit capable of carrying current; and
a transconductance circuit loop connected to control said circuit capable of carrying current to pull current from said inductive load to said reference potential when said inductive load sources current to said body diode sufficient to cause the voltage across said body diode to exceed a predetermined trip voltage. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method for operating an H-bridge power circuit that provides power to a load that includes an inductive component, comprising:
-
sensing a voltage between a high side driver and a low side driver of said H-bridge power circuit;
if said voltage exceeds a predetermined level, diverting a current from said high side driver to said low side driver. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A circuit for protecting upper transistors of an H-bridge circuit that provides power to a load that has an inductive component, comprising:
a transconductance circuit loop connected between one side of said inductive component and a gate of a low side transistor of said H-bridge, said transconductance circuit operating to pull current from said inductive component to ground when said inductive load sources current to a body diode of said high side transistor. - View Dependent Claims (12, 13, 14, 15)
-
16. An H-bridge power circuit for providing power to a load that includes an inductive component, comprising:
-
means for sensing a voltage between a high side driver and a low side driver of said H-bridge power circuit;
and means for diverting a current from said high side driver to said low side driver if said voltage exceeds a predetermined level. - View Dependent Claims (17, 18, 19, 20)
-
Specification