Citation

Toh, Kheng Hin and Lee, Lini and Islam, Md. Shabiul (2023) A Real Time Amplitude Compensation Method Using LED Current Regulation System For Optical Encoders. Journal of Engineering Science and Technology., 18 (2). pp. 1292-1308. ISSN 1823-4690

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Abstract

Encoders are angular and speed position sensors that are mainly use in a motor feedback system. Optical encoders use the photodiodes to generate photocurrent in response to the light source or rather the Light Emitting Diodes (LEDs). The LEDs will degrade over time while the optical strength is sensitive to the temperature. Amplitude of an encoder signals is one of the three critical parameters in determining an encoder performance. This paper will present a method of regulating the LED current to maintain and compensate the amplitude signals using the available LED current. This method has been simulated using MATLAB and implemented in an encodersystem designed using the 0.18 µm CMOS process. The proposed system has been fabricated, measured and the results are compared to the simulated results. The outcome shows that the system is able to regulate the LED current to compensate for the degradation and loss of LED power due to external variation such as temperature that affects the amplitude of the signals. From the measurement, without this method of amplitude compensation, the (Voltage Peak to Peak) Vpp of the signals can varies roughly +/- 200mV across temperature, but with this proposed method, the amplitude is maintained with variation around +/- 10mV by regulating the LED current.

Item Type:	Article
Uncontrolled Keywords:	Amplitude correction, Analog LED regulation for encoders, Encoders, Sinusoidal optical encoders
Subjects:	Q Science > QC Physics > QC221-246 Acoustics. Sound
Divisions:	Faculty of Engineering (FOE)
Depositing User:	Ms Nurul Iqtiani Ahmad
Date Deposited:	02 Jun 2023 00:53
Last Modified:	02 Jun 2023 00:53
URII:	http://shdl.mmu.edu.my/id/eprint/10700

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