Continuous-wave time-of-flight CMOS detector with commonmode feedback for strong background light applications

A novel CMOS demodulation detector for time-offlight
applications is presented. It can handle large amounts of
background light by removing the resulting common-mode signal
at the detector level. A common-mode feedback circuit is used on
top of a current-assisted photonic demodulator (CAPD) to
remove the incoming light that is not correlated to the
modulation signal. A dynamic element matching (DEM) scheme
is implemented to remove mismatches in the compensating
current sources that operate at nanoampere currents. The
detector is fabricated in a 0.35 μm process and is used to measure
the phase of a 1 MHz square-wave modulated laser signal on top
of a background light, more than 100 times more powerful,
without the use of optical filters. Measurements are performed
with and without DEM, demonstrating its need. The detector is a
candidate for long range outdoor time-of-flight applications
where background light can become multiple orders of
magnitude larger than the modulated light.

ISBN:978-1-4799-8202-8

Publication year:2015

Keywords:Current-Assisted Photonic Demodulator, Photonic demodulation, Optical detectors, Time-of-flight imaging, CMOS demodulation detector, Strong background light, 3D camera

Accessibility:Open