An improved method of highly accurate supply detection using bandgap reference circuit and its implementation in a pseudo BiCMOS process

This paper presents an improved method of highly accurate supply detection by using a bandgap circuit and its implementation in a comparatively inexpensive BiCMOS process. The process is the vanilla N-well complementary metal oxide semiconductor process technology with added deep N-well and P-well layers. The circuit consisting of a simple bandgap core with a resistance divider produces a supply detection method with high accuracy. In this method the low supply threshold can be set at any voltage according to the system requirement and the process, supply and temperature variation of this threshold voltage is very tight which produce an accurate low supply sense as a result. This circuit is implemented in 0.5 mum technology. The layout of the circuit also presented in this paper and the performance improved in layout are discussed. Simulation results and test data are given to prove the functionality and performance of the presented method.