Title :
A new feedback circuit based charge-pump for wide-range and low-jitter DLL suitable for PET imaging applications
Author :
Mondal, Sabir Ali ; Pal, Shovon ; Sahoo, Manodipan ; Mondal, Prasenjit ; Rahaman, Hafizur
Abstract :
Charge-pump adds/removes charges to/from a loop-filter via constant current source/sink. Channel length modulation effect in the locking range of DLL (Delay Locked Loop) worsens the matching between this current source and sink. A new feedback circuit based charge-pump is proposed here to reduce this mismatch for PET (Positron Emission Tomography) imaging applications. Simulations are performed in UMC 180nm process to validate the effectiveness of the technique. Here current mismatch reduction of 28.08% and 86.25% is achieved for bias current of 10 uA and 40 uA respectively at 3.3V supply. Locking range of DLL is enhanced by (Vtn + Vtp + 2Von) compared to the existing feedback circuit in literature. The advantage of the feedback circuit is also observed at lower supply voltages viz. 2.5V and 1.8V at 180 nm technology node.
Keywords :
charge pump circuits; circuit feedback; constant current sources; delay lock loops; jitter; positron emission tomography; PET imaging application; bias current; channel length modulation effect; charge-pump circuit; constant current sink; constant current source; current mismatch reduction; delay locked loop; feedback circuit; loop-filter; low-jitter DLL; positron emission tomography; size 180 nm; wide-range DLL; Charge pumps; Detectors; Feedback circuits; Modulation; Positron emission tomography; ADLL (Array of DLL); APD (Avalanche photodiode); Charge pump; DLL; PET; PMT (Photomultiplier tube); TDC (Time to digital converter);
Conference_Titel :
Devices, Circuits and Systems (ICDCS), 2014 2nd International Conference on
Conference_Location :
Combiatore
DOI :
10.1109/ICDCSyst.2014.6926125
