Current sense amplifier with common mode rejection
AssigneeCirrus Logic, Inc.
InventorsVamsikrishna Parupalli, Itisha Tyagi
Life of this patent
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Abstract
The overall performance of a current sense amplifier system may be improved by increasing the common mode rejection of the system. In particular, improved current sense amplifier systems of this disclosure may be configured to use a first ADC path to measure a current flowing through a device, a second ADC path to measure a common mode value, a memory element to store a calibration value, and a summer block to output a voltage proportional to the measured current through the device by correcting a voltage value output by the first ADC path based on the measured common mode value of the second ADC path and the stored calibration value.
Claims26
An apparatus for measuring a current through a device, comprising:
- a first analog-to-digital conversion (ADC) path coupled to the device and configured to measure a current value;
- a second ADC path coupled to the device and configured to measure a common mode value;
- a memory element comprising a stored calibration value;
- and
- a summer block coupled to the first ADC path, the second ADC path, and the memory element, wherein the summer block is configured to output a voltage proportional to the measured current through the device by correcting a voltage value output by the first ADC path based, at least in part, on the measured common mode value of the second ADC path and the stored calibration value.
A method for measuring a current through a device, comprising:
- measuring, with a first analog-to-digital conversion (ADC) path, a current value for the current through the device;
- measuring, with a second ADC path, a common mode value for the device;
- receiving, from a memory element, a stored calibration value;
- and
- determining the current through the device by correcting a voltage proportional to the measured current value based, at least in part, on the measured common mode value and the stored calibration value.
A mobile device, comprising:
- a transducer;
- a controller integrated circuit (IC) coupled to the transducer, wherein the controller IC is configured to measure a current through the transducer, the controller IC comprising:
- a first analog-to-digital conversion (ADC) path coupled to the device and configured to measure a current value;
- a second ADC path coupled to the device and configured to measure a common mode value;
- a memory element comprising a stored calibration value;
- and
- a summer block coupled to the first ADC path, the second ADC path, and the memory element, wherein the summer block is configured to output a voltage proportional to the measured current through the device by correcting a voltage value output by the first ADC path based, at least in part, on the measured common mode value and the stored calibration value.
Dependencies are inferred from the claim text.