Integrated optocoupler circuit design in high voltage bipolar-CMOS-DMOS process

Optocouplers comprising an optical sensor and electrical readout circuits are commonly fabricated on a single chip to reduce the size of electrical systems and enlarge circuit board capacity. Nonetheless, the inclusion of two separate components on a single chip still results in high cost and area overhead exceeding those of monolithic chips. In this paper, we propose an optocoupler integrating an optical sensor and readout circuit on a single chip using the TSMC high voltage bipolar-CMOS-DMOS (BCD) process. The combination of high current bipolar junction transistors with this mature CMOS processing technology makes such a monolithic chip achievable and the reduced chip size greatly expands its applicability. This approach to circuit integration also helps to enhance the reliability of the resulting chip, while reducing the overall costs and facilitating mass production.