Patent ID: 8638127

Claim:
An undervoltage detector, comprising: a voltage divider network comprising: a first circuit coupled to a first terminal of an input bias voltage source, the first circuit including a number M of semiconductor devices, wherein M is at least one, a second circuit coupled in series with the first circuit, the second circuit including a first voltage divider resistor, a second voltage divider resistor, and a circuit node between the first voltage divider resistor and the second voltage divider resistor, and a third circuit in series with the second circuit and coupled to a second terminal of the input bias voltage source, the third circuit including a number P of semiconductor devices, wherein P is at least one, wherein a ratio of the number P to the number M is equal to a ratio of a resistance of the second voltage divider resistor to a resistance of the first voltage divider resistor; a comparator having a first input coupled to the circuit node and a second input coupled to a voltage reference; and a current mirror configured to receive a first current from the first circuit, the current mirror configured to provide a bias current to the comparator.