US 11,843,387 B1
Tx-Rx synchronization for reflective optoelectronic systems in portable electronic devices
Susan A. Thompson, Half Moon Bay, CA (US); Anup K. Sharma, Sunnyvale, CA (US); Christopher G Zeleznik, San Jose, CA (US); and Harish Venkataraman, Half Moon Bay, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Aug. 5, 2021, as Appl. No. 17/395,234.
Claims priority of provisional application 63/072,779, filed on Aug. 31, 2020.
Int. Cl. H03L 7/085 (2006.01); H03L 7/081 (2006.01); H05B 47/10 (2020.01)
CPC H03L 7/085 (2013.01) [H03L 7/081 (2013.01); H05B 47/10 (2020.01)] 20 Claims
OG exemplary drawing
 
1. An optoelectronic system for an electronic device, the optoelectronic system comprising:
a transmit side comprising:
a phase-locked loop configured to:
receive, as input, a system clock signal;
decimate the system clock signal to a decimated input signal;
oversample the decimated input signal to an oversampled clock signal;
decimate the oversampled clock signal to a sampling signal; and
decimate the sampling signal to a frequency of the decimated input signal;
a shift register configured to receive the sampling signal and, in response, output a sequence of digital values;
a converter configured to receive the sequence of digital values and to output a current corresponding to each value of the sequence of digital values;
a delay-locked loop configured to receive current output from the converter and to apply a phase delay thereto; and
a light-emitting element configured to receive as input output from the delay-locked loop.