| 主权项 |
1. A method of converting an analog signal into a digital output code using an analog to digital converter comprising:
a sampling section comprising at least a first array of switched capacitors having one end connected to a first common node; and at least one analog voltage comparator comprising a first input connected to the common node, a second input and an output, said comparator being adapted to provide at said output a signal (OUTCOMP) having two levels based on the comparison of analog voltage values provided at said inputs;the method comprising the steps of:
a) storing at least one offset digital value representing an estimation or a measure of a voltage offset at said first common node; b) providing the analog signal to the sampling section and sampling said analog signal during a sampling interval in order to obtain a sampled voltage value; c) forcing the first input of the comparator to a predetermined voltage value during a first time period which is a portion of said sampling interval ending before the end of said sampling interval; d) after the end of said first time period and before the end of said sampling interval period, injecting a charge amount into or pulling a charge amount from said first common node, said charge amount depending on said at least one stored offset digital value, sampling said output signal and increasing or decreasing a digital value stored in first digital counter based on the level of said sampled output signal; e) at the end of said sampling interval, sampling said output signal and obtaining one or more bits of said digital output code based on the level of said sampled output signal; f) repeatedly performing steps b)-e); and g) correcting or leaving unchanged said at least one stored offset digital value based on the content of said first digital counter. |
