J4 ›› 2013, Vol. 40 ›› Issue (4): 130-136.doi: 10.3969/j.issn.1001-2400.2013.04.022

• Original Articles • Previous Articles     Next Articles

Design of a trimmed current reference with a low temperature drift

TANG Hualian;ZHUANG Yiqi;ZHANG Li;JING Xin;DU Yongqian   

  1. (Ministry of Education Key Lab. of Wide Band-Gap Semiconductor Materials and Devices, Xidian Univ., Xi'an  710071, China)
  • Received:2012-05-09 Online:2013-08-20 Published:2013-10-10
  • Contact: TANG Hualian E-mail:lily_thl@126.com

Abstract:

Component tolerances and mismatches due to process variations severely degrade the performance of bandgap reference circuits. Based on device mismatch models, a current reference Iref with adjustable output current from 15μA to 80μA is designed. A compensated circuit is used to reduce the temperature drift. To achieve more accurate current reference, an 8bit bi-directional trimming array with 127 current levels is proposed. This digitally programmable array is binary weighted for accuracy and flexibility. Simulation shows that the temperature coefficient is 26ppm/℃ over the wide range of -40℃ to 120℃when the output current is 15μA. Based on the CMOS 0.13μm technology, the measurement results show that the trimmed range and precision for current reference are -14.3%·Iref~14.3%·Iref and 0.11%·Iref, respectively. The circuit could be applied to high precision A/D and D/A converters.

Key words: current reference, temperature coefficient, process variations, trimming

CLC Number: 

  • TN45