IP Library Granted Patent US 10,840,927
Granted Patent B1
US 10,840,927 · App. 16/414,600 · Granted Nov 17, 2020

Low power current steering digital-to-analog converter

Inventors: Dan Shen (Irvine, CA); Balakishan Challa (Irvine, CA); Lorenzo Crespi (Costa Mesa, CA)
Assignee: SYNAPTICS INCORPORATED
H03M1/002H03M1/0604H03M1/66H03M1/00H03M1/10H03M1/664
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Quick Facts
Patent No.
US 10,840,927
App. No.
16/414,600
Granted
Nov 17, 2020
Kind
B1
Abstract

Systems and methods according to one or more embodiments provide a low power current steering digital-to-analog converter. In one example, a device includes a current cell including a plurality of switches. The device further includes a current cell controller configured to selectively operate the plurality of switches. The plurality of switches is selectively operated to cause the current cell to generate a current signal in response to a first data signal. The plurality of switches is selectively operated to disable the current cell in an absence of the first data signal. The plurality of switches is selectively operated to transition the current cell to a common mode state before the current cell receives the first data signal. Related systems and methods are also provided.

Claims (37)

1. A device comprising:

a current cell comprising a plurality of switches; and

a current cell controller configured to selectively operate the plurality of switches to:

cause the current cell to generate a current signal in response to a first data signal comprising a first input data pulse signal and a second input data pulse signal;

enable the current cell responsive to a first edge transition of the first input data pulse signal and transition to a common mode state before the first edge of the second input data pulse signal;

output a differential signal in the presence of a first edge transition of the second input data pulse signal; and

disable the current cell responsive to a second edge transition of the first input data pulse signal.

2. The device of claim 1 , wherein the current cell further comprises a current source and/or a current sink coupled to the plurality of switches.

3. The device of claim 1 , further comprising a delay element coupled to the current cell controller, wherein the delay element is configured to delay the first transition edge of the first data signal to obtain the first transitional edge of a second data signal.

4. The device of claim 1 , further comprising a delay element coupled to the current cell controller, wherein the delay element is configured to delay a second transition edge of a second data signal for a period of time to obtain the second transitional edge of the first data signal.

5. The device of claim 4 , wherein the delay element is configurable and includes a delay equal to zero.

6. The device of claim 1 , further comprising a conversion circuit coupled to the current cell, wherein the conversion circuit is configured to receive the current signal from the current cell and convert the current signal to a corresponding voltage signal.

7. The device of claim 6 , wherein, in the common mode state:

the current cell is configured to allow current flow from a voltage supply node to a ground node, and

a common mode voltage associated with the current cell is approximately equal to a common mode voltage associated with the conversion circuit.

8. The device of claim 1 , wherein the device comprises an N-bit digital-to-analog converter comprising a plurality of corresponding current cells, current cell controllers, and delay elements.

9. The device of claim 8 , wherein the N-bit digital-to-analog converter comprises a plurality of digital-to-analog converters, and wherein each digital-to-analog converter comprises at least one of each of the current cells, the current cell controllers, and the delay elements.

10. The device of claim 1 , wherein the device is a current steering digital-to-analog converter.

11. The device of claim 1 , wherein each of the plurality of switches comprises a metal-oxide semiconductor transistor.

12. A method of operating a current steering digital-to-analog converter, the method comprising:

receiving, by a current cell controller, a first data signal comprising a first input data pulse signal and a second input data pulse signal;

enabling the current cell responsive to a first edge transition of the first input data pulse signal;

transitioning a current cell to a common mode state before the first edge of the second input data pulse signal is received;

generating a differential signal in the presence of a first edge transition of the second input data pulse signal; and

disabling the current cell responsive to a second edge transition of the first input data pulse signal.

13. The method of claim 12 , wherein the transitioning comprises selectively operating, by the current cell controller, a plurality of switches of the current cell.

14. The method of claim 12 , wherein the current cell further comprises a current source and/or a current sink coupled to the plurality of switches.

15. The method of claim 12 , further comprising delaying, by a delay element, the first transition edge of the first data signal to obtain the first transition edge of a second data signal.

16. The method of claim 12 , further comprising delaying, by a delay element, a second transition edge of a second data signal for a period of time to obtain the second transition edge of the first data signal.

17. The method of claim 16 , further comprising receiving, by the current cell controller, the second data signal and, if the current cell is in a disabled state, causing, by the current cell controller, the current cell to transition to the common mode state before the current cell receives the first data signal.

18. The method of claim 12 , further comprising:

receiving, by a conversion circuit, the current signal; and

converting, by the conversion circuit, the current signal to a corresponding voltage signal.

19. The method of claim 18 , wherein, in the common mode state,

the current cell allows current flow from a voltage supply node to a ground node, and

a common mode voltage associated with the current cell is approximately equal to a common mode voltage associated with the conversion circuit.

20. The method of claim 12 , wherein the current steering digital-to-analog converter comprises an N-bit digital-to-analog converter comprising a plurality of corresponding current cells, current cell controllers, and delay elements.

Assignments (2)
SECURITY INTEREST Recorded Feb 14, 2020
From: SYNAPTICS INCORPORATED
To: WELLS FARGO BANK, NATIONAL ASSOCIATION
Reel/Frame 051936/0103 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 22, 2019
From: SHEN, DAN; CHALLA, BALAKISHAN; CRESPI, LORENZO
To: SYNAPTICS INCORPORATED
Reel/Frame 049259/0110 →