Three-limit time-base circuit

Abstract

The invention provide a three-limit time-base circuit composed of analogue integrated circuit operational amplifier A (or voltage comparator B), few separate electronic elements by using new principleand ingenious connection mode. The three-limit time-base circuit has top and bottom limit main control functions completely compatible to all functions of classic 555 time-base circuit can be used asultra-top and bottom limit control circuit and astable, monostable and bistable circuit. The invention increases exceed bottom limit protection and control function, when inputted sensing circuit hasfault, fault display and protection control can be executed in time to prevent the main control circuit from being out of control. The invention, used in control circuits for temperature, pressure, water level etc., may improve security, and prevent severe accidents (such as fire hazard). So, the invention has wide use in electronic application field such as household electrical appliances, simple controllers, and high cost performance of products are provided.

Description

1. Technical Field: [0001] The invention belongs to a three-limit time-base circuit that is simply formed by using an analog integrated circuit operational amplifier A (or a voltage comparator B), adding a small amount of discrete electronic components, using new principles and cleverly connecting. Its upper and lower limit master control function is fully compatible with all the functions of the classic 555 time base circuit, and can be used as a super upper and lower limit control circuit and astable, monostable and bistable circuit. The invention adds a monitoring function beyond the bottom limit, and when the input sensing circuit fails, the fault display and protection control can be performed in time to prevent the main control circuit from losing control. It can be used in temperature, pressure, water level and other control circuits to improve its safety performance. Avoid serious accidents (such as fire). Therefore, the present invention is more widely used in electro...

AI Technical Summary

Problems solved by technology

The principle is: the voltage divider sets the upper limit and the lower limit, and the comparator compares the input potential with the upper limit and the lower limit. If the input potential exceeds the upper limit or the lower limit potential, the two comparators trigger the R terminal or the S terminal of the R-S flip-flop with pulses respectively. The Q terminal outputs the corresponding level to control the load through the driver output. This control process and principle can only complete the upper and lower limit control function, and there is no fault protection control function at all. It is a blank item.

In addition, there are disadvantages in performance. The reset potential of the reset terminal MR (pin 4) is not set properly, and the dispersion is too large, and it cannot be compared with the input potential.

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