Sample and hold readout system and method for ramp analog to digital conversion
AssigneeOmniVision Technologies, Inc.
InventorTrung Thanh Nguyen
Life of this patent
Estimating the term…
Abstract
A sample and hold readout system and method for ramp analog to digital conversion is presented in which an optical array is read out using a sample and hold circuit such that each sample is used to charge a sample and hold capacitor and is read out during a hold phase using an amplifier that drives an ramp analog to digital converter. The sample and hold circuit transitions to a tracking phase wherein the optical array input drives an amplifier that drives the sample and hold capacitor then transitions to a sample phase where the sample and hold capacitor is connected to the optical array output directly.
Claims10
A sample and hold circuit comprising:
- an input to the sample and hold circuit from an output of an optical array;
- a Field Effect Transistor (FET) with a source connected to an output of the sample and hold circuit;
- a T-switch between the input and a gate of the FET, the T-switch comprising:
- a first switch electrically coupled to the output of the optical array at one end of the first switch and electrically coupled to a common point of the T-switch on the other end of the first switch;
- a second switch electrically coupled to the common point of the T-switch on one end of the second switch and the other end of the second switch electrically coupled to a sample and hold capacitor and the gate of the FET;
- a third switch electrically coupled to the common point of the T-switch on one end of the third switch and electrically coupled to a ground on the other end of the third switch.
Dependencies are inferred from the claim text.