Current starved DAC-controlled delay locked loop
Patent Information
- Authority / Receiving Office
- CN · China
- Current Assignee / Owner
- ATMEL CORP
- Publication Date
- 2006-12-20
- Estimated Expiration
- Not applicable · inactive patent
Smart Images
Figure 1 Figure 2 Figure 3
Abstract
Description
technical field
[0001] The present invention relates to semiconductor circuits, and more particularly to an improved delay locked loop (DLL) design for power savings and fast shutdown and restart. Background technique
[0002] The design of current controlled delay cells is relatively well known in the art. A pair of cascaded CMOS inverters, with an additional p-type and n-channel transistor inserted into the current path and reflected from the reference current, will establish a fixed delay through a cell. No matter how a conventional current-controlled DLL is designed, it has many disadvantages. The current value must be accurate and must match the delay circuit. Short delays for input signals require high operating currents. To compensate for other variations, such as voltage supply or temperature variations, high value current mirrors are required. These features increase power requirements. In addition, these systems suffer from noise interference.
[0003] Under ...