Monostable protective circuit and automatic control circuit for water heater

Abstract

The invention relates to a fuel gas water heater controller, in particular to a monostable protective circuit for the fuel gas water heater controller. The monostable protective circuit comprises a comparer N6B and a first triode V33, wherein the negative input end of the comparer N6B is connected with a power supply and the collector of the first triode V33 respectively; the emitter of the first triode V33 is grounded; the positive input end of the comparer N6B is connected with the power supply through a fourth resistor R49 and grounded through a fifth resistor R50; and the resistance values of the fourth resistor R49 and the fifth resistor R50 are the same. The negative input end of the comparer N6B is at a high level or low level by controlling the collector and the emitter of the first triode V33 to be switched on or off. The monostable protective circuit is relatively independent in the whole control circuit, so that the dry combustion of a water heater without a water flow signal is avoided when a singlechip or an application specific integrated circuit (ASIC) device fails.

Description

technical field [0001] The invention relates to a protection circuit, in particular to a monostable protection circuit for a gas water heater controller. Background technique [0002] The main controllers used in the existing domestic automatic forced exhaust or intelligent constant temperature gas fast water heaters are all composed of single-chip microcomputers (MCU) or customized ASIC devices, plus corresponding peripheral hardware circuits and embedded control programs. Automatic control system, see appendix figure 1 . Under the control of single-chip microcomputer (and embedded program) or ASIC device, the main controller controls the whole system, completes the prescribed actions, and realizes specific functions. The core of this automatic control system is a single-chip microcomputer (MCU) or ASIC device, and its function is like the human brain. A single-chip microcomputer or ASIC device itself includes thousands or tens of thousands of electronic transistors....

AI Technical Summary

Problems solved by technology

[0003] The components of traditional gas water heaters are mainly controlled by single-chip microcomputer. When the hardware or software (embedded control program) or ASIC device of the single-chip microcomputer fails (the cause of the failure cannot be forecast), when some of its functions are damaged or disturbed, the control function of the microcontroller or ASIC device may fail

In this case, when the water flow sensor does not detect that there is water entering the water heater from the water inlet pipe, that is, there is no water flow signal, but due to the failure of the single-chip microcomputer, it is mistakenly thought that there is water entering the water heater, and the single-chip microcomputer controls the main solenoid valve drive circuit to open. Then start the water heater and dry-burn the water heater, which will cause gas leakage and cause danger to users

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