4 is an illustration of another digital integrator for continuous digital AZ offset compensation, according embodiments of the present disclosure. 3 is an illustration of a digital integrator for continuous digital AZ offset compensation, according embodiments of the present disclosure.įIG. 2 is an illustration of another example system for high precision current sensing, according to embodiments of the present disclosure.įIG. 1 is an illustration of an example system for high precision current sensing, according to embodiments of the present disclosure.įIG. In combination with any of the above embodiments, the current sensing circuit may have a sensing FET transistor topology.Įmbodiments of the present disclosure may include an apparatus including a DC/DC converter, AC/DC converter, motor driver, LED drivers, battery chargers, or USB electronic device including any of the current sensing circuits of the above embodiments.Įmbodiments of the present disclosure may include methods performed by any of the current sensing circuits or apparatuses of the above embodiments. In combination with any of the above embodiments, the current sensing circuit may have a shunt resistor topology. In combination with any of the above embodiments, the correction circuit may be further configured to convert the offset voltage to the correction signal continuously in order to prevent degradation due to a temperature drift of the offset compensation. In combination with any of the above embodiments, the correction circuit may be further configured to use the DAC to close a feedback loop of the digital Auto-Zero compensation of the sense amplifier. In combination with any of the above embodiments, the correction circuit may be further configured to use the comparator and the digital integrator to generate the correction signal as an input of a digital to analog converter (DAC). In combination with any of the above embodiments, the correction circuit may be further configured to use a comparator connected to the inputs of the sense amplifier to control a digital integrator configured to generate the correction signal. In combination with any of the above embodiments, the correction circuit may be further configured to evaluate the offset voltage and issue the correction signal continuously. The current sensing circuit may include a correction circuit configured to evaluate an offset voltage of the sense amplifier, and to issue a correction signal to the sense amplifier based upon the evaluated offset voltage. The current sensing circuit may include a current sense amplifier. SUMMARYĮmbodiments of the present disclosure may include a current sensing circuit. Globally, the error induced by the SA circuit offset is equal to Vos/Vdrop. The voltage drop across the sensing element may be referenced as “Vdrop”.
The offset of the SA circuit may be referenced as “Vos”. The offset of the SA circuit may define the accuracy of measurement. Sensing of the current in a load may be performed by probing the voltage drop on a sensing element (such as a current shunt resistor or sensing FET). SA circuits are used in different sensing schemes, like shunt resistor current sensing topologies, or power switch and sense field-effect transistor (FET) current sensing topologies.
Sensing and measurement of a current in power regulators, USB power switches, and other circuits is commonly performed using a current sense amplifier (SA) circuit.
The USB load switches must provide load protection by measuring current very accurately and limiting power delivery. Another typical example of applications where current sensing and measurement are commonly used is in USB powered electronics. Current sensing through a shunt resistor may be used to control the switching regulator power supply, and current sensing precision may factor into the performance of such regulators. As higher efficiency for low power applications is sought, more and more linear regulator solutions are being replaced by switching regulator solutions. One example use of current sensing and measurement is in power regulation.
BACKGROUNDĬurrent sensing and measurement are commonly performed in all electronics applications related to power delivery for direct current (DC) and alternating current (AC), like DC/DC convertors, AC/DC convertors, motor drivers, light emitting diode (LED) drivers, battery chargers, universal serial bus (USB) powered electronics and many other applications. The present disclosure relates to current sensing and measurement and, more particularly, to a high-precision current sensing using a sense amplifier with digital Auto-Zero (AZ) offset compensation. 30, 2017, the contents of which are hereby incorporated in their entirety.