Analog/digital converter and voltage comparator capable of fast producing of output offset voltage
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsOsamu Matsumoto, Toshio Kumamoto
Life of this patent
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Abstract
An A/D converter includes a sample-hold circuit, A/D converting stages connected in series to the sample-hold circuit, and an encoder/latch circuit which adds 3-bit digital signals issued from the A/D converting stages to each other for outputting a signal of 9 bits. The sample-hold circuit and the A/D converting stages each include a differential amplifier. Differential outputs of each differential amplifier are short-circuited for a predetermined initial period in each sampling period.
Claims11
An analog/digital converter comprising:
- data holding means for taking in first analog data for a first period and holding the same for a second period;
- a plurality of analog/digital converting stages connected in series to said data holding means;
- and
- latching means for latching digital data issued from each of said analog/digital converting stages, wherein
- one of said analog/digital converting stages connected to said data holding means includes:
- analog/digital converting means for converting second analog data supplied from said data holding means into digital data and outputting the same to said latching means,
- digital/analog converting means connected to said analog/digital converting means for converting said digital data into third analog data,
- subtracting means for subtracting said third analog data from said second analog data and thereby outputting result data of the subtraction,
- first amplifying means connected to said subtracting means for receiving a first bias voltage for said second period and amplifying said result data of the subtraction supplied from said subtracting means for said first period, and
- first voltage supply means for supplying a first auto-zero voltage to an output terminal of said first amplifying means only for a predetermined initial period in said second period.
An analog/digital converter comprising:
- data holding means for differentially receiving first analog data for a first period and holding the same for a second period;
- a plurality of analog/digital converting stages connected in series to said data holding means;
- and
- latching means for latching digital data issued from each of said analog/digital converting stages, wherein
- one of said analog/digital converting stages connected to said data holding means includes:
- analog/digital converting means for converting second analog data differentially supplied from said data holding means into digital data and outputting the same to said latching means,
- digital/analog converting means connected to said analog/digital converting means for converting said digital data into third analog data,
- subtracting means for subtracting said third analog data from said second analog data and thereby outputting result data of the subtraction,
- first amplifying means connected to said subtracting means for receiving a first bias voltage for said second period and amplifying said result data of the subtraction supplied from said subtracting means for said first period, and
- first switching means for short-circuiting differential output terminals of said first amplifying means only for a predetermined initial period in said second period.
A voltage comparator for receiving data for a data receiving period and comparing said data with a reference voltage to output a result of the comparison for a data comparing period, comprising:
- amplifying means for comparing said data with said reference voltage and amplifying the result of the comparison;
- and
- voltage supply means for supplying an auto-zero voltage to an output terminal of said amplifying means only for a predetermined initial period in said data receiving period.
Dependencies are inferred from the claim text.