Voltage-mode DAC driver with parallel output resistance tuning
View Patent ↗A voltage-mode digital-to-analog converter (DAC) includes input circuitry and an array of output impedance units disposed in parallel. The input circuitry receives a digital word of N bits. A selectable number of the output impedance units are activated to produce a desired aggregate output impedance. The selectable number is free to be a number different than N.
1. A voltage-mode digital-to-analog converter (DAC), comprising:
input circuitry to receive a digital word of N bits;
an array of output impedance units disposed in parallel;
wherein a configurably selectable number of the output impedance units are activated to produce a desired aggregate output impedance; and
wherein the configurably selectable number is free to be a number different than N.
2. The voltage-mode DAC according to claim 1 , wherein the configurably selectable number is less than N.
3. The voltage-mode DAC according to claim 1 , wherein the configurably selectable number is greater than N.
4. The voltage-mode DAC according to claim 1 , wherein the input circuitry includes a scaler to scale the digital word of N bits.
5. The voltage-mode DAC according to claim 4 , wherein the scaler is operative to convert the digital word of N bits to a number of bits other than N that corresponds to the number of activated output impedance units.
6. The voltage-mode DAC according to claim 1 , wherein each of the output impedance units exhibits a same resistance value.
7. The voltage-mode DAC according to claim 1 , wherein each of the output impedance units exhibits a resistance value that is free to be different from resistance values exhibited by other output impedance units.
8. A method of operation in a voltage-mode DAC, the method comprising:
receiving a digital word of N bits;
providing an array of output impedance units disposed in parallel;
activating a configurably selectable number of the output impedance units to produce a desired aggregate output impedance; and
wherein the configurably selectable number is free to be a number different than N.
9. The method according to claim 8 , wherein the configurably selectable number is greater than N.
10. The method according to claim 8 , wherein the configurably selectable number is less than N.
11. The method according to claim 8 , further comprising:
scaling the digital word of N bits based on the activated selectable number of output impedance units.
12. The method according to claim 11 , wherein the scaling comprises:
converting the digital word of N bits to a number of bits other than N that corresponds to the number of activated output impedance units.
13. The method according to claim 8 , wherein the activating is carried out via a calibration interface.
14. The method according to claim 8 , wherein the activating is carried out adaptively in response to an adaptive module.
15. A voltage-mode driver, comprising:
input circuitry to selectively receive one of N bits of a digital word;
an output impedance unit configured to be disposed in parallel with other output impedance units from other voltage-mode drivers to define an activated number of output impedance units to generate an aggregate output impedance;
an enable input responsive to an enable signal to activate the input circuitry; and
wherein the activated number of output impedance units is free to be a number other than N.
16. The voltage-mode driver of claim 15 , wherein the output impedance units exhibit a same resistance value.
17. The voltage-mode driver of claim 15 , wherein the output impedance units exhibit a resistance value that is free to be different from resistance values exhibited by other output impedance units.