Current monitoring circuit having controlled sensitivity to temperature and supply voltage
First Claim
1. An apparatus for monitoring current flowing through a shunt in a circuit, comprising:
- a comparator having two output states and being responsive to a voltage developed across a shunt in the circuit as a result of the current flowing through the circuit, the shunt being coupled to the comparator, so that the comparator assumes one of its two output states when the voltage developed across the shunt is greater than a predetermined threshold switching voltage of the comparator and the other of its two output states when the voltage developed across the shunt is less than said threshold switching voltage, said threshold switching voltage changing as a result of changes in a supply voltage of the circuit or changes in temperature; and
a threshold switching voltage sensitivity control circuit coupled to and controlling the threshold switching voltage of the comparator for providing selectable control of sensitivity of the threshold switching voltage to changes in a supply voltage of the circuit and for providing selectable control of a sensitivity of the threshold switching voltage to changes in temperature.
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Accused Products
Abstract
An integrated circuit including a comparator having two output states and being responsive to a voltage developed across a shunt in the circuit so that the comparator assumes one of its two output states when the voltage developed across the shunt is greater than a threshold switching voltage and the other of its two output states when the voltage developed across the shunt is less than the threshold switching voltage. The integrated circuit additionally includes a threshold switching voltage sensitivity control circuit, coupled to and controlling the comparator, for controlling a sensitivity of the threshold switching voltage to changes in a supply voltage of the lamp circuit and for controlling a sensitivity of the threshold switching voltage to changes in temperature of the integrated circuit.
68 Citations
17 Claims
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1. An apparatus for monitoring current flowing through a shunt in a circuit, comprising:
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a comparator having two output states and being responsive to a voltage developed across a shunt in the circuit as a result of the current flowing through the circuit, the shunt being coupled to the comparator, so that the comparator assumes one of its two output states when the voltage developed across the shunt is greater than a predetermined threshold switching voltage of the comparator and the other of its two output states when the voltage developed across the shunt is less than said threshold switching voltage, said threshold switching voltage changing as a result of changes in a supply voltage of the circuit or changes in temperature; and a threshold switching voltage sensitivity control circuit coupled to and controlling the threshold switching voltage of the comparator for providing selectable control of sensitivity of the threshold switching voltage to changes in a supply voltage of the circuit and for providing selectable control of a sensitivity of the threshold switching voltage to changes in temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17)
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15. An integrated circuit for monitoring current flowing through a circuit, comprising:
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comparator means, having at least a test input coupled to one node in the circuit, a reference input coupled to another node in the circuit, and an output, for comparing a voltage at the test input with a voltage at the reference input to control the output in response to a difference between the voltage at the test input and the voltage at the reference input, the difference between the voltage at the test input and the voltage at the reference input changing as a result of changes in a supply voltage of the circuit or changes in temperature; and a sensitivity control means, coupled to and controlling the comparator means, for providing selectable control of (1) a sensitivity of the difference between the voltage at the test input and the voltage at the reference input of the comparator means to changes in a supply voltage of the circuit and (2) a sensitivity of the difference between the voltage at the test input and the voltage at the reference input of the comparator means to changes in temperature.
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Specification