Turn-off automatic-control PWM (Pulse Width Modulation) wave control power circuit for gas sensor

Abstract

The invention discloses a turn-off automatic-control PWM (Pulse Width Modulation) wave control power circuit for a gas sensor. The turn-off automatic-control PWM wave control power circuit comprises a turn-off control circuit, a PWM wave generation circuit and a stable voltage output circuit, wherein the turn-off control circuit comprises resistors R5 and R6 and an NMOS (N-channel Metal Oxide Semiconductor) tube T2, one end of the resistor R5 is connected with a positive end V1 of an external power supply, the other end of the resistor R5 is connected with the grid of the NMOS tube T2 via the resistor R6, the source of the NMOS tube T2 is grounded, the drain of the NMOS tube T2 is connected a resistor R4 of the PWM wave generation circuit and the grid of an NMOS tube T1 respectively, the output end of an external turn-off signal P1 is connected with the resistors R5 and R6 respectively, and the resistor R5 is a pull-up resistor. In the power circuit, a few discrete components are used, stable power is supplied to the gas sensor, the circuit is simple, stable and reliable, is low in cost and has a few components, the equipment cost using the power circuit is relatively reduced, and the power circuit is convenient to promote and utilize.

Description

technical field [0001] The invention relates to a power supply circuit for a gas sensor, in particular to a shut-off self-controlling PWM wave control power supply circuit for a gas sensor. Background technique [0002] With the development of science and technology and the improvement of human living standards, people's requirements for their surrounding environment are also constantly improving. People pay special attention to gases that affect their own safety, such as methane, sulfur dioxide and other flammable and hazardous gases. For this reason, various Portable gas detection equipment, such equipment is generally relatively cheap, for example, environmental methane testers, various mining portable methane testers, various mine sulfur dioxide testers, etc., the accuracy and sensitivity of such portable gas detection equipment It mainly depends on the characteristics of the gas sensor, and the power supply part of the gas sensor is an important factor for the stable an...

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Problems solved by technology

[0002] With the development of science and technology and the improvement of human living standards, people's requirements for their surrounding environment are also constantly improving. People pay special attention to gases that affect their own safety, such as methane, sulfur dioxide and other flammable and hazardous gases. For this reason, various Portable gas detection equipment, such equipment is generally relatively cheap, for example, environmental methane testers, various mining portable methane testers, various mine sulfur dioxide testers, etc., the accuracy and sensitivity of such portable gas detection equipment It mainly depends on the characteristics of the gas sensor, and the power supply part of the gas sensor is an important factor for the stable and reliable operation of the gas sensor. For this reason, many experts and scholars at home and abroad have proposed different power supply methods for the gas sensor, including the use of high-precision regulated power supply, However, its cost is too high and it is difficult to promote it in the field of environmental testing and coal mines. Especially in some small mines with relatively backward technical conditions and economic conditions, there are also proposals to use high-precision processing chips, but this solution also has the problem of high cost. , making it difficult to promote the equipment applicable to the method in the coal mine market

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