A Multi-channel Time-division Multiplexing Low-dropout Regulator For Thermo-optic Phase Tuning In Electronic-photonic Heterogeneously-converging ICs

Electronic-photonic-converged ICs are getting more and more attention in the post-Moore era for its low power consumption,high bandwidth,and the benefits of combining both the electrons and photons.It plays an important role in multiple applications,including Li DAR,quantum communication,artificial intelligence,etc.Thermo-optic phase tuning is one of the most important techniques to manipulate optical signals in those electronic-photonic heterogeneously-converging ICs.However,most state-of-the-art designs still apply the bench-top or board-level circuits,significantly limiting the scalability and making it difficult for real-world application.This paper presents a multi-channel low-dropout regulator(LDO)to realize on-chip power supply for the electronic-photonic heterogeneously-converging ICs.It is a promising solution to replace the conventional bench-top or board-level power supply,consequently,improve the efficiency,reduce the cost,and extend the scalability of the whole systems.The paper starts with the importance of the electronic-photonic heterogeneously-converging ICs,it also points out the current limit on scalability.Then,it reviews and summarizes the structures and materials of the state-of-the-art thermo-optic phase shifter designs.After that,we discuss the evolution of the LDO structures and the operating principles of the time-division multiplexing mechanism.After that,we present the design details and the realizations of out design.Then,we analyze the output error,stability and scalability of it.After that,we present the layout.Finally,we verify the effectiveness with UMC 130nm CMOS process in Cadence Virtuoso.Compared with conventional solutions,our design significantly reduces the total chip area.We present a split-output controller architecture.It can share the compensation capacitor without influencing the stability.To reduce the output error,we also present a Grey-code addressing technique that avoids the clock feed-through created by the timing error.Based on the above consideration,this paper realizes four-channel sinusoidal tracking at 1.2V power supply.The total chip area is 0.056mm~2,saving more than 67.5%chip area compared with the conventional solutions.