Current sensing with rdson correction

A current sensor comprising:

• a processing device;
• an on-chip temperature sensor, coupled to provide a measured temperature signal of a MOS transistor switch to the processing device;
• a memory device coupled to the processing device and configured to store a temperature sensor gain and offset correction function and a voltage correction function;
• and
• wherein the processing device is configured to:
• receive a gate drive voltage for the MOS transistor switch;
• receive the measured temperature signal and calculate a corrected temperature from the measured temperature signal using the stored temperature sensor gain and offset correction function;
• instruct at least one circuit element to multiply a measured RDSON voltage drop by a voltage correction factor to yield a corrected RDSON voltage drop, wherein the voltage correction factor is determined using the stored voltage correction function;
• and
• calculate a current of the MOS transistor switch from the corrected RDSON voltage drop for use by a voltage regulator to regulate a voltage signal.

A system comprising:

• a power source configured to provide a voltage signal;
• a voltage regulator configured to regulate the voltage signal from the power source and produce an output voltage signal, wherein the voltage regulator includes a MOS transistor switch used in producing the output voltage signal, and wherein the voltage regulator includes a calibrated current sensor used to sense current though the MOS transistor switch, wherein the calibrated current sensor comprises:
• a processing device;
• an on-chip temperature sensor, coupled to provide a measured temperature signal of a MOS transistor switch to the processing device;
• a memory device coupled to the processing device and configured to store a temperature sensor gain and offset correction function and a voltage correction function;
• and
• wherein the processing device is configured to:
• receive a gate drive voltage for the MOS transistor switch;
• receive the measured temperature signal and calculate a corrected temperature from the measured temperature signal using the stored temperature sensor gain and offset correction function;
• instruct at least one circuit element to multiply a measured RDSON voltage drop by a voltage correction factor to yield a corrected RDSON voltage drop, wherein the voltage correction factor is determined using the stored voltage correction function;
• and
• calculate a current of the MOS transistor switch from the corrected RDSON voltage drop for use by a voltage regulator to regulate a voltage signal.