Patent ID: 6954390
Filing Date: 2005-10-11
Classification: G11C

Abstract:
1. A sensing circuit, comprising: a first integrator circuit having a first integrator input electrically coupled to a reference level, a second integrator input to which an input is applied, and first and second integrator outputs at which first and second output signals are provided, respectively, the integrator circuit further having an amplifier circuit having pairs of differential input and output nodes, the integrator circuit periodically switching the electrical coupling of each of the differential input nodes to a respective integrator input and the electrical coupling of each of the differential output nodes to a respective integrator output; a second integrator circuit having first and second integrator inputs coupled to a respective integrator output of the first integrator circuit and first and second integrator outputs; a clocked comparator having first and second input nodes electrically coupled to a respective integrator output of the second integrator circuit and further having an output node, the clocked comparator periodically comparing voltage levels of the first and second input nodes and generating an output signal having a logic state based therefrom; and a current source having a first pair of current output nodes coupled to a respective integrator output of the first integrator circuit, and further having a second pair of current output nodes coupled to a respective integrator output of the second integrator circuit, the current source switching the coupling of each current output node of the first pair to a respective integrator output of the first integrator circuit, and each current output node of the second pair to a respective integrator output of the second integrator circuit based on the logic state of the output signal of the comparator.