A CMOS Monolithic Light to Sigma-Delta Modulator for Environmental Monitoring Applications

In this paper, a CMOS monolithic light to sigma-delta modulator for environmental monitoring applications is newly proposed. The proposed chip is attractive due to the fact that analog processing circuits and light sensor are integrated robustly and compactly. The output signal of the proposed chip is a pulse stream, it could be easily sent over a wide range of transmission media, such as PSN, radio, optical, IR, ultrasonic, and etc. Another innovation is that the light noise at low frequency band can be easily removed into high frequency band by following the characteristics of the proposed chip. Based upon the device parameters of 0.35 mu m 2P4M CMOS technology with 3.0 V power supply, all the functions and performance of the proposed monolithic light to sigma-delta modulator for environmental monitoring applications are successfully tested and proven through SPICE simulations. The chip area is 1.998 x 1.616 mm(2). The proposed chip is suitable for environmental monitoring applications.