The invention relates to lower-than-lower-limit reverse control time base circuit. All functions of a 555 time base circuit are completely compatible, and new functions are expanded. The technical problem that a conventional master
control circuit for higher-than-upper-limit control and lower-than-lower-limit control and a timing circuit are out of control due to failures and cannot timely
cut power supplied to a load off to cause potential safety hazards. The technical scheme is that: a
lower limit reference circuit, a comparison circuit and a triggering protection circuit are arranged; when a sensing circuit abnormally fails, the inversion of a post-stage circuit is preferably triggered, and a lower-than-lower-limit reverse control protection function is realized to forcibly
cut the power supplied to the load off and reliably prevent the failures from causing uncontrollability. When applied to temperature, pressure,
water level and timing control circuits, the lower-than-lower-limit reverse control time base circuit can improve the safety performance and avoid serious accidents such as fire when in use. Therefore, the lower-than-lower-limit reverse control time base circuit has high practical value and higher
cost performance, and is more widely applied in the fields of electronic application such as small
home appliance and simple measurement, timing, control, safety protection and the like.