Digital-analog converter
First Claim
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1. A digital analog converter, coupled to a reference voltage, for receiving a multi-bit digital signal and producing an analog value, said converter comprising:
- a first resistor array consisting of a plurality of resistors connected in series to divide said reference voltage into M output voltages, where M is a positive integer;
a first switch array for receiving said output voltages of said first resistor array to select two adjacent ones of said output voltages in accordance with a first number of upper bits of said digital signal;
a first select switch for outputting one of said two adjacent output voltages selected by said first switch array;
a second select switch for outputting the other of said two adjacent output voltages selected by said first switch array;
two buffer amplifiers, coupled to said select switches, each receiving a different one of the two selected output voltages from said select switches in accordance with the states of said first and second select switches;
a second resistor array consisting of a plurality of resistors connected in series to receive said output voltages from said buffer amplifiers and divide said output voltages into N voltages, where N is a positive integer;
a second switch array for selecting one of said output voltages from said second resistor array in accordance with the contents of a second number of lower bits of said digital signal;
an averaging circuit including means for receiving the selected output voltage from the second switch array and obtaining an average of said selected output voltage; and
an alternating controller for synchronously controlling said select switches and said averaging circuit.
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Abstract
A digital-analog converter wherein reference voltage is divided by a first string-like resistor array, whose two adjacent outputs are selected by a first switch array depending upon the contents of upper bits of a digital signal and applied to the both ends of a second string-like resistor array, and one of switches in a second switch array is selectively turned on responsive to the contents of lower bits of said digital signal to pick up one of the divided voltages of said second resistor array.
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Citations
8 Claims
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1. A digital analog converter, coupled to a reference voltage, for receiving a multi-bit digital signal and producing an analog value, said converter comprising:
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a first resistor array consisting of a plurality of resistors connected in series to divide said reference voltage into M output voltages, where M is a positive integer; a first switch array for receiving said output voltages of said first resistor array to select two adjacent ones of said output voltages in accordance with a first number of upper bits of said digital signal; a first select switch for outputting one of said two adjacent output voltages selected by said first switch array; a second select switch for outputting the other of said two adjacent output voltages selected by said first switch array; two buffer amplifiers, coupled to said select switches, each receiving a different one of the two selected output voltages from said select switches in accordance with the states of said first and second select switches; a second resistor array consisting of a plurality of resistors connected in series to receive said output voltages from said buffer amplifiers and divide said output voltages into N voltages, where N is a positive integer; a second switch array for selecting one of said output voltages from said second resistor array in accordance with the contents of a second number of lower bits of said digital signal; an averaging circuit including means for receiving the selected output voltage from the second switch array and obtaining an average of said selected output voltage; and an alternating controller for synchronously controlling said select switches and said averaging circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification