Intentionally non-monotonic digital-to-analog converter
AssigneeSemtech Corporation
InventorVictor Marten
Life of this patent
Estimating the term…
Abstract
A digital-to-analog converter comprises capacitor stack (61, 62), the common point of which is the output of the converter. Digitally controlled switches (66-70), which may be discrete outputs from a microcontroller, selectively apply first or second potentials to points in the capacitor stack, either directly (66, 70) or through resistors (63-65).
Claims6
Apparatus having an output line comprising:
- first, second, and third nodes, said second node defining the output line;
- a first capacitor between the first and second nodes;
- a second capacitor between the second and third nodes;
- a first switch selectably connecting said first node to either a first potential or a second potential;
- a second switch selectably connecting said second node via a first resistor to the first potential, to the second potential, or to an open connection;
- a third switch selectably connecting said second node via a second resistor to the first potential, to the second potential, or to an open connection, said second resistor smaller in value than the first resistor;
- a fourth switch selectably connecting said second node to the second potential or to an open connection;
- said first switch, second switch, third switch, and fourth switch each controlled by digital circuitry.
A method for use with apparatus comprising a first capacitor between first and second nodes and a second capacitor between the second node and a third node, said second capacitor defining an output, said method defined with respect to first and second potentials, said method defined with respect to first and second resistors, the second resistor smaller in value than the first resistor, said third node connected to said second potential, said method comprising the steps of:
- connecting said first and second nodes to the second potential;
- disconnecting the second node from the second potential;
- disconnecting the first node from the second potential and connecting it to the first potential;
- connecting the second node to a first one of the first and second potentials through the first resistance for a first time interval;
- connecting the second node to the second one of the first and second potentials through the second resistance for a second time interval;
- and
- connecting the second node to the first one of the first and second potentials through the second resistance for a third time interval.
Dependencies are inferred from the claim text.