Power supply monitor

Abstract

In a power supply monitor which outputs a reset signal when the power supply voltage decreases, a first voltage is generated by a first voltage generator in proportion to a power supply voltage, and a comparator supplying a first signal when the first voltage becomes lower than a reference voltage. On the other hand, a slewing rate detector supplies a second signal when a slewing rate of decreasing in power supply voltage is larger than a threshold value. Then, a signal generator supplying a signal set by a trailing edge of the second signal received from the slewing rate detector except a period after the second signal is received and reset by a trailing edge of the first signal received from the comparator. That is, even if the power supply voltage decreases, the monitor does not generate a reset signal when the decrease in the power supply voltage is instantaneous.

Dependencies are inferred from the claim text.