Patent ID: 7535398
Filing Date: 2009-05-19
Classification: H03M,H04N

Abstract:
1. An analog-to-digital converter (ADC) comprising: a first circuit configured to sample a reset voltage, amplify the sampled reset voltage, and subtract a first reference voltage from the amplified reset voltage to produce a first difference; a second circuit configured to sample a signal voltage, amplify the sampled signal voltage, and subtract a second reference voltage from the amplified signal voltage to produce a second difference; a differential amplifier coupled to the first circuit and the second circuit, the differential amplifier configured to produce a third difference based on a comparison of the first difference and the second difference; a comparator coupled to the differential amplifier, the comparator configured to compare an output of the differential amplifier with at least one predetermined comparison voltage and output a result of the comparison as a digital value; and a digital-to-analog converter (DAC) coupled to the first circuit, the second circuit, and the comparator, the DAC configured to control the first and second reference voltages in response to the digital value.