Complementary voltage interpolation circuit
AssigneeNorth American Philips Corporation, Signetics Division
InventorRudy J. van de Plassche
Life of this patent
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Abstract
The invention centers around a system for interpolating between multiple pairs of main complementary signals to generate further pairs of complementary signals. An input circuit (10) supplies the main signals. The interpolation is done with two strings (12) of a selected number of impedance elements (R.sub.0 -R.sub.N-1 and R.sub.NO -R.sub.NN-1). Each pair of main signals is supplied to a corresponding pair of nodes along the strings. The interpolated signals are taken from other pairs of corresponding nodes along the strings. The interpolation system is particularly suitable for use in an analog-to-digital converter of the folding type.
Claims23
An electronic circuit having input means responsive to an input parameter for providing multiple pairs of substantially complementary main signals of which each varies with the input parameter as it varies;
- characterized by interpolation means comprising two strings of a selected number of impedance elements in which:
- a node is located between each pair of consecutive impedance elements in each string, at one end of one string, and at a corresponding end of the other string;
- the pairs of nodes located at like positions along the strings comprise pairs of corresponding input nodes and pairs of corresponding interpolation nodes, whereby at least one of the input nodes lies between the ends of each string;
- at least one of the interpolation nodes is located between the two most distant input nodes in each string;
- each pair of corresponding input nodes receives a different one of the pairs of main signals;
- and each pair of corresponding interpolation nodes provides a pair of corresponding interpolated signals.
An electronic circuit for converting an analog input voltage which varies across an input voltage range into a digital code consisting of a set of most significant bits and a set of least significant bits, there being:
- means for supplying the most significant bits;
- means for providing a plurality of reference voltages spaced across the input voltage range;
- means responsive to the input and reference voltages for generating pairs of substantially complementary main signals, the voltage waveform for each main signal as a function of the input voltage being of a repetitive rounded triangular shape;
- and means for operating on the main signals to produce the least significant bits;
- characterized in that:
- the means for generating comprises:
- means for producing a like plurality of intermediate voltages respectively corresponding to the reference voltages and cumulatively representative of the input voltage, the waveform for each intermediate voltage as a function of the input voltage being of a rounded triangular shape with an extreme value occurring when the input voltage is slightly different from the corresponding reference voltage;
- and means for combining selected ones of the intermediate voltages to produce the main signals;
- and
- the means for supplying comprises:
- further means for combining selected ones of the intermediate voltages to produce pairs of substantially complementary further signals;
- and a group of coarse comparators, each providing a different one of the most significant bits by comparing the signals of a corresponding pair of the further signals.
An electronic circuit comprising:
- input means responsive to an input parameter for providing multiple pairs of substantially complementary main signals, each of which varies with the input parameter as it varies;
- two strings of a like number of resistors in which (1) a node is located between each pair of consecutive resistors in each string, at one end of one string, and at a corresponding end of the other string, (2) the pairs of nodes located at like positions along the strings comprise pairs of corresponding input nodes and pairs of corresponding interpolation nodes, whereby at least one of the input nodes lies between the ends of each string, (3) at least one of the interpolation nodes lies between each pair of consecutive input nodes along each string, and (4) each resistor in one string has largely the same resistance as the like-positioned resistor in the other string;
- and
- means connecting the input means to the strings to provide each pair of corresponding input nodes with a different one of the pairs of main signals, each pair of corresponding interpolation nodes thereby providing a pair of substantially complementary interpolated signals.
Dependencies are inferred from the claim text.