Patent ID: 6420909
Filing Date: 2002-07-16
Classification: H03F,H03K

Abstract:
A circuit for comparing a first voltage and a second voltage, the circuit comprising:a first comparator comprising a first current divider dividing a bias current in accordance with the first and second voltages and providing two currents, and a first current differentiation circuit receiving the two currents and providing an output signal dependent upon a difference between the two currents, wherein at least one of said first current divider and said first current differentiation circuit weights one of the two currents with respect to the other current so that the output signal is only provided when a difference between the first and second voltages exceeds an offset value; and a bias generator connected to said first comparator providing a bias voltage thereto, said bias generator comprising a second comparator comprising a second current divider dividing a bias current in accordance with values of a third and fourth voltage and providing two currents, and a second current differentiation circuit receiving the two currents and providing a second output signal dependent upon a difference between the two currents; said first and second comparators comprising substantially identical components arranged in a substantially identical configuration.