Voltage supervisor with low quiescent current

A voltage supervisor, comprising:

• a reference current generator having a current mirror, the current mirror configured to provide a first current that is proportional to a difference in gate-to-source voltages of a first transistor and a second transistor;
• a third transistor having a gate coupled to the current mirror, a source adapted to be coupled to a power supply, and a drain coupled to a first terminal of a resistor, the third transistor is configured to provide a second current proportional to a difference in a supply voltage and the difference in gate-to-source voltages of the first transistor and the second transistor;
• and
• a fourth transistor having a gate coupled to the gate of the third transistor, a source adapted to be coupled to the power supply, and a drain having a drain voltage indicative of the supply voltage above a threshold;
• wherein:
• the resistor includes a second terminal coupled to a source of a fifth transistor, wherein a gate of the fifth transistor is coupled to a gate of the first transistor and a gate of the second transistor.