Voltage regulator current load sensing
View Patent ↗A DC-DC converter including digital circuitry for determining load current supplied to a load. In some embodiments the digital circuitry determines the load current differently based on whether the DC-DC converter is operating in pulse frequency modulation mode or pulse width modulation mode. In some embodiments the DC-DC converter includes circuitry for determining if a short circuit or over current condition exists.
1. A method useful in operation of a DC-DC converter, comprising:
determining if an output voltage of the DC-DC converter is less than a predefined under voltage threshold;
setting a short circuit alarm signal if the output voltage of the DC-DC converter is determined to be less than the predefined under voltage threshold;
generating a comparison signal indicating whether the output voltage of the DC-DC converter is greater than a desired output voltage of the DC-DC converter plus a tolerance voltage;
determining an average over time of the comparison signal;
determining if the average over time of the comparison signal is greater than a predefined overcurrent voltage threshold value;
setting an over current alarm signal if the average over time of the comparison signal is greater than the predefined value; and
ceasing operation of the DC-DC converter in response to the over current alarm signal being set.
2. The method of claim 1 wherein the determining if the output voltage of the DC-DC converter is less than the predefined voltage threshold:
comparing the output voltage to the predefined under voltage threshold to determine whether the output voltage is less the predefined under voltage threshold.
3. The method of claim 1 wherein the predefined under voltage is substantially ground potential.
4. The method of claim 1 wherein the predefined under voltage is a predefined voltage level that is less than any operation voltage level expected to be observed during operation of the DC-DC converter.
5. The method of claim 1 wherein the predefined under voltage is a predefined voltage level indicating a short circuit of one of the DC-DC converter output and the load.
6. The method of claim 1 further comprising:
ceasing operation of the DC-DC converter in response to the short circuit alarm signal being set.