US Patent 7541954 Touch control apparatus and analog-to-digital converting apparatus and method thereof

Disclosed are an analog-to-digital converting apparatus, an analog-to-digital converting method and a touch control apparatus adapted to convert a divided voltage generated according to a power voltage and a ground voltage. The analog-to-digital converting apparatus includes a first sample-and-hold circuit for sampling and holding the divided voltage, a second sample-and-hold circuit for sampling and holding the power voltage, and an analog-to-digital converter coupled to the first and second sample-and-hold circuits. The analog-to-digital converter converts the divided voltage from the first sample-and-hold circuit to a digital value according to the power voltage held by the second sample-and-hold circuit and the ground voltage. The first and second sample-and-hold circuits sample the divided voltage and the power voltage before the analog-to-digital converter converts the divided voltage, and hold the sampled divided voltage and the sampled power voltage at least during conversion of the divided voltage by the analog-to-digital converter.