High side, current sense amplifier using a symmetric amplifier
AssigneeMaxim Integrated Products, Inc.
InventorGregory L. Schaffer
Life of this patent
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Abstract
A self-contained, bi-polar high-side current sense amplifier which detects the magnitude and polarity of current flowing from one device to another, is disclosed. The amplifier has a symmetric architecture having two inputs and two outputs. One output is active for positive input signals corresponding to current flow in one direction, and the other output is active for negative input signals corresponding to current flow in an opposite direction. A symmetric current mirror in the amplifier provides the OR'ing function required to provide only one output at a time. The amplifier also utilizes aluminum sense and gain resistors, which allows cancellation of resistor temperature coefficients.
Claims29
A bidirectional current sense amplifier comprising:
- first and second terminals for connection to a current sense resistor to sense the magnitude and polarity of the potential difference between the first and second terminals;
- a first circuit coupled to the first and second terminals for providing an output on a first output terminal, responsive to the magnitude of the potential difference between the first and second terminals;
- and
- a second circuit for providing a two-state signal on a second output terminal responsive to the polarity of the potential difference between the first and second terminals.
A bidirectional current sensing integrated circuit comprising:
- first and second terminals for connection to a current sense resistor to sense the magnitude and polarity of the potential difference between the first and second terminals;
- an amplifier for providing an output responsive to a potential difference between the first and second terminals of a first polarity;
- an amplifier for providing an output responsive to a potential difference between the first and second terminals of a second polarity;
- OR'ing circuitry for OR'ing the outputs of the amplifiers and providing a first output responsive thereto;
- and,
- comparing circuitry for comparing the outputs of the amplifiers and providing a second output responsive thereto.
A bidirectional current sensing integrated circuit comprising:
- a resistor connected to first and second terminals for connection in a circuit for current to flow therethrough;
- an amplifier for providing an output responsive to a potential difference across the resistor of a first polarity;
- an amplifier for providing an output responsive to a potential difference across the resistor of a second polarity;
- OR'ing circuitry for OR'ing the outputs of the amplifiers and providing a first output responsive thereto;
- and,
- comparing circuitry for comparing the outputs of the amplifiers and providing a second output responsive thereto.
A method for sensing the magnitude and polarity of current flowing through a sense resistor, comprising the steps of:
- sensing a voltage difference across the sense resistor;
- determining the magnitude of the current based on the voltage difference;
- determining the polarity of the current based on the voltage difference;
- providing a first output indicative of the magnitude of the current;
- and
- providing a second output indicative of the polarity of the current.
Dependencies are inferred from the claim text.