CMOS Integrated Optical Isolator for Power Transistor Gate Driver

This paper presents an integrated solution for the galvanic isolation between the control parts on one side and the power transistors and their associated drivers on the other side. This has been carried out with an optical isolator integrated and associated with the integrated driver. A fully integrated optical receiver including photodiode technology associated with the signal processing circuit (SPC) is described in this paper. This circuit is developed using standard 0.35 pm CMOS technology. The main electro optical characteristics of several integrated photodetectors are presented. The detectors demonstrated DC responsivitivies between 0.04A/W and 0.32A/W at 1V reverse bias. These photodetectors exhibit a bandwidth about 10 MHz when exited by an optical square-wave signal modulated by 450nm ZLaser at an optical power level in the range of micro watts. The measured results of on-chip integrated photodiode with the proposed SPC showed a pulse width distortion of 90ns.