An On-Chip Digital Monostable Multivibrator using Inverter-based Delay Chains

Monostable multivibrator or one-shot timer is widely used in signal processing. In this paper, a simple and useful way to realize retriggerable monostable multivibrator by using digital logic gates is presented. The basic circuit is composed of one D flip-flop, one NAND gate, one inverter (INV) and two inverter-based delay chains. The width of the output pulse is adjusted through tuning the delay of the inverter-based delay chain. The retriggerable characteristic is realized by resetting all the delayed signals when new triggering occurs in the current monostable period. The basic circuit is designed and fabricated on-chip using a 180 nm standard CMOS process with effective area less than 1200 mu m(2). The retriggerable version is realized in a FPGA platform. Both simulated and measured results are in agreement with the theoretical analysis.