Patent ID: 9554072
Date: 2017-01-24
CPC Classifications: H03M,H04N

Claim:
1. An analog to digital converter for converting an analog signal from an image sensor to a digital value, the converter comprising: a first stage including a first analog to digital converter for obtaining a first number of bits of the digital value, the first analog to digital converter comprising an integrator with a first gain and a comparator for comparing the integrated signal with a first reference signal; an intermediate amplifier for multiplying the output of the integrator after conversion of the first number of bits in the first stage by a predetermined gain based on the first gain; and a second stage including a second analog to digital converter for obtaining a second number of bits of the digital value based on the signal input from the intermediate amplifier, wherein the second analog to digital converter is a ramp analog to digital converter and comprises a comparator for comparing the signal input to the second analog to digital converter with a reference analog ramp signal, and a digital register for storing the digital value corresponding to the time period in which the analog ramp signal crosses the input signal.