Patent ID: 9197233
Filing Date: 2015-11-24
Classification: H03M,H04N

Abstract:
1. A circuit for converting an input analog current signal into an output digital signal, comprising: an input current from a detector; a detector buffer circuit having its input coupled to a detector and its output coupled to a charge integration node; an integration capacitor coupled to the integration node; a step charge subtractor coupled to the integration node; a dual function comparator coupled to the integration node; a step charge node coupled to the step charge subtractor; a step charge capacitor having a first plate coupled to the step charge node and an opposed second plate coupled to a push-pull voltage swing; a residual signal buffer coupled to the dual function comparator output; a state latch input coupled to the dual function comparator output; a n-bit counter input coupled to the state latch output; and a m-bit time-to-digital converter couple to the residual signal buffer output.