| CPC H03K 17/002 (2013.01) [G05F 1/46 (2013.01); H03K 5/24 (2013.01)] | 26 Claims |
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1. A system, comprising:
a comparator having a first input, a second input, and an output;
a first voltage divider having an input and an output, wherein the input of the first voltage divider is coupled to a first power rail, and the output of the first voltage divider is coupled to the first input of the comparator;
a second voltage divider having an input and an output, wherein the input of the second voltage divider is coupled to a second power rail, and the output of the second voltage divider is coupled to the second input of the comparator;
a power multiplexer coupled to the first power rail, the second power rail, and a first circuit; and
a control circuit coupled to the output of the comparator and the power multiplexer, wherein
the first voltage divider is configured to divide a first supply voltage from the first power rail by a first divider to generate a first divided voltage, and output the first divided voltage at the output of the first voltage divider;
the second voltage divider is configured to divide a second supply voltage from the second power rail by a second divider to generate a second divided voltage, and output the second divided voltage at the output of the second voltage divider;
the first divider is different from the second divider; and
the control circuit is configured to
compare a voltage level of the second supply voltage with a threshold voltage level,
set the first divider greater than the second divider if the voltage level of the second supply voltage is less than the threshold voltage level, and
set the first divider less than the second divider if the voltage level of the second supply voltage is greater than the threshold voltage level.
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