D/a converter
AssigneeFujitsu Semiconductor Limited
InventorHisao SUZUKI
Life of this patent
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Abstract
A digital-to-analog (D/A) converter includes first resistors coupled in series, second resistors respectively coupled to the first resistors and each having a resistance twice as large as the resistance of the first resistor, and first switch circuits respectively coupled to the second resistors. Third resistors each have a resistance twice as large as the resistance of the first resistor. Second switch circuits each are coupled to the third resistors and a GND wire. A control circuit controls the first and second switch circuit in accordance with the digital input signals to set a state of a connection node to either one of a first voltage, a second voltage, and a high impedance.
Claims13
A digital-to-analog (D/A) converter that generates an analog signal according to digital input signals, the D/A converter comprising:
- a plurality of first resistors coupled in series between a first output terminal and a second output terminal from which the analog signal is outputted, the first resistors having a same resistance;
- a plurality of second resistors including first terminals respectively coupled to the plurality of first resistors and each having a resistance twice as large as the resistance of the first resistor, the first output terminal being coupled to the first terminal of one of the plurality of second resistors;
- a plurality of first switch circuits respectively coupled to second terminals of the plurality of the second resistors;
- a third resistor having a resistance twice as large as the resistance of the first resistor and including a first terminal coupled to one of the first terminals of the second resistors except for one second resistor that is coupled to the first output terminal;
- a second switch circuit including a first terminal coupled to a second terminal of the third resistor and a second terminal coupled to a first wire;
- and
- a control circuit coupled to the first and second switch circuits and configured to generate a first signal to control the first switch circuits and to generate a second signal to control the second switch circuit, in accordance with the digital input signals,
- wherein one or more of the plurality of the first switch circuits, which is coupled to the second resistor that is coupled to a node between the first output terminal and a connection node arranged between two adjacent first resistors and to which the first terminal of the third resistor is coupled, is controlled to set a state of a connection node arranged between the one or more first switch circuit and the corresponding second resistor to either one of a first voltage, a second voltage that is different from the first voltage, and a high impedance.
Dependencies are inferred from the claim text.