A Continuous-Time Ripple Reduction Technique for Spinning-Current Hall sensors

Junfeng Jiang, Wilco J. Kindt, Kofi A.A. Makinwa

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)
27 Downloads (Pure)

Abstract

This paper presents a new ripple-reduction technique for spinning-current Hall sensors, which obviates the need for lowpass filtering to suppress the ripple caused by up-modulated sensor offset. A continuous-time ripple-free output is achieved by the use of three ripple reduction loops (RRLs), which continuously sense the offset ripple and then use this information to drive a feedback
loop that cancels sensor offset before amplification. Since no low-pass filter is involved, the bandwidth of the resulting system can be much higher than the spinning frequency. Moreover, since the front-end no longer has to process sensor offset, the requirements on its dynamic range can be significantly relaxed. A prototype system consisting of a Hall sensor readout system realized in a 0.18 m CMOS process was combined with three off-chip RRLs realized with off-chip electronics.At a spinning frequency of 1 kHz, the RRLs reduce the offset ripple by more than 40 dB to about 10 T, while also achieving low offset (25 T) and wide bandwidth (over 100 kHz).
Original languageEnglish
Pages (from-to)1525-1534
Number of pages10
JournalIEEE Journal of Solid State Circuits
Volume49
Issue number7
DOIs
Publication statusPublished - 2014

Keywords

  • Hall sensor
  • ripple reduction loop (RRL)
  • spinning-current

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