Current sense circuit
AssigneeGentex Corporation
InventorsG. Bruce Poe, Robert R. Turnbull
Life of this patent
Estimating the term…
Abstract
A current sense circuit includes a current sense device and a voltage sense device. The current sense device is positioned to sense a drive current provided to a load by a drive circuit. The voltage sense device is coupled across the current sense device and receives a variable threshold signal at a first input and provides an output signal on an output whose value is dependent upon whether a sense signal at a second input is above or below the variable threshold signal. A level of the variable threshold signal changes in response to a voltage level of a power supply that supplies the drive current to the drive circuit.
Claims20
A current sense circuit, the circuit comprising:
- a current sense device positioned to sense a drive current provided by a drive circuit to a load;
- and
- a voltage sense device coupled across the current sense device, the voltage sense device receiving a variable threshold signal at a first input and providing an output signal on an output whose value is dependent on whether a sense signal representing the sensed drive current and applied to a second input is above or below the variable threshold signal, wherein a level of the variable threshold signal changes in response to a voltage level of a power supply that supplies the drive current to the drive circuit.
A current sense circuit, the circuit comprising:
- a sense resistor positioned to sense a drive current provided by a drive circuit to a load;
- and
- a differential amplifier having a positive input and a negative input coupled across the sense resistor, the differential amplifier receiving a variable threshold signal at the negative input and providing an output whose value is dependent on whether a sense signal representing the sensed drive current and applied to the positive input is above or below the variable threshold signal, wherein a level of the variable threshold signal changes in response to a voltage level of a power supply that supplies the drive current to the drive circuit.
A mirror assembly, comprising:
- an electrochromic element;
- a drive circuit for providing a drive current to the electrochromic element;
- a current sense device positioned to sense the drive current provided by the drive circuit;
- and
- a voltage sense device coupled across the current sense device, the voltage sense device receiving a variable threshold signal at a first input and providing an output signal on an output whose value is dependent on whether a sense signal representing the sensed drive current and applied to a second input is above or below the variable threshold signal.
Dependencies are inferred from the claim text.