Design of PID Coprocessing Module for CPT Atomic Clock Control SoC

Abstract

The CPT (Coherent Population Trapping) atomic clock is very small because there is no microwave cavity. However, the circuit control system is becoming the constraint of further miniaturization of CPT atomic clock. The CPT atomic clock control SoC integrates control related circuit into a single chip. There are many control loops in the CPT atomic clock which require PID (Proportional-Integral-Derivative) algorithm. CPU in this SoC can not afford the computation of PID algorithm. So a PID coprocessing module is integrated into this SoC. The PID algorithm can be decomposed into multiply-add operations. The coprocessing module mainly consists of a multiply-add module. Compared with SoC without PID coprocessing module, SoC with this module can reduce the time of calculating PID algorithm to 24.808%, and the area consumption increases by only 8.89%.