Patent ID: 8878511

Claim:
A circuit comprising: a first current path comprising a first floating-gate transistor having a programmable threshold voltage, said first floating-gate transistor being diode-connected; a second current path comprising: a second floating-gate transistor having a programmable threshold voltage, said second floating-gate transistor being diode-connected; and a resistor; a differential amplifier including a first input coupled to the first current path, a second input coupled to the second current path, and an output configured to control a reference current path; a power supply terminal; a first transistor including a first terminal coupled to the power supply terminal, a second terminal coupled to the first current path, and a gate terminal coupled to the output of the differential amplifier; and a second transistor including a source terminal coupled to the power supply terminal, a drain terminal coupled to the second current path, and a gate terminal coupled to the output of the differential amplifier, wherein the first and second transistors have approximately equal sizes, and the programmable threshold voltage of the first floating-gate transistor is higher than the programmable threshold voltage of the second floating-gate transistor.