US Patent No. 10,462,869

LIGHT CONTROL CIRCUIT AND OPTICAL ENCODER SYSTEM


Patent No. 10,462,869
Issue Date October 29, 2019
Title Light Control Circuit And Optical Encoder System
Inventorship Kuan-Choong Shim, Penang (MY)
Gim-Eng Chew, Penang (MY)
Assignee PIXART IMAGING INC., Hsin-Chu County (TW)

Claim of US Patent No. 10,462,869

1. A light control circuit, comprising:a first squaring circuit configured to receive a first detected signal, a second detected signal and a common mode voltage signal, and output a first current squaring signal, wherein the second detected signal is out of phase from the first detected signal;
a second squaring circuit configured to receive a third detected signal, a fourth detected signal and the common mode voltage signal, and output a second current squaring signal, wherein the third detected signal is perpendicular to the first detected signal, the fourth detected signal is perpendicular to the second detected signal, and the common mode voltage signal is obtained according to the first, second, third and fourth detected signals;
a square sum circuit configured to calculate a sum of current squaring of the first current squaring signal and the second current squaring signal;
a converting circuit configured to convert the sum of current squaring to a detected voltage signal; and
a constant voltage source configured to output a reference voltage signal.