Power supply circuit for anti-explosion oil filling tax control machine
阅读说明：本技术 一种用于防爆加油税控机的电源电路 (Power supply circuit for anti-explosion oil filling tax control machine ) 是由 焦金城 顾晗 于 2019-12-18 设计创作，主要内容包括：本发明公开了一种用于防爆加油税控机的电源电路,过压过流保护单元及DC-DC降压电路单元作为单独的电源模块进行注塑密封,留出焊脚焊接到板卡上；其中,过压过流保护单元包括：与电源输入端依次连接的稳压二极管V203、电阻R206、电阻R207并接地；电阻R206、电阻R207的连接节点连接至三极管V204的基极,三极管V204的集电极连接至三极管V208基极,三极管V208集电极通过电阻R214连接至大功率MOS管V207的源极；电阻R214并联在三极管V709的基极与发射极之间,三极管V709的集电极连接大功率MOS管V207的栅极,大功率MOS管V207的漏极作为保护输出端连接至DC-DC降压电路单元的输入端。本发明一是可以更好的满足本安电路标准的防爆要求,二是做到对防爆加油税控机的电源过压,过流保护。(The invention discloses a power circuit for an explosion-proof refueling tax control machine.A overvoltage and overcurrent protection unit and a DC-DC voltage reduction circuit unit are used as independent power modules for injection molding and sealing, and a welding leg is reserved for welding on a board card; wherein, overvoltage overcurrent protection unit includes: a voltage stabilizing diode V203, a resistor R206 and a resistor R207 which are sequentially connected with the power supply input end are grounded; the connection node of the resistor R206 and the resistor R207 is connected to the base electrode of the triode V204, the collector electrode of the triode V204 is connected to the base electrode of the triode V208, and the collector electrode of the triode V208 is connected to the source electrode of the high-power MOS transistor V207 through the resistor R214; the resistor R214 is connected in parallel between the base electrode and the emitter electrode of the triode V709, the collector electrode of the triode V709 is connected with the grid electrode of the high-power MOS tube V207, and the drain electrode of the high-power MOS tube V207 is used as a protection output end and is connected to the input end of the DC-DC step-down circuit unit. The invention can better meet the explosion-proof requirement of the intrinsic safety circuit standard, and can realize the power supply overvoltage and overcurrent protection of the explosion-proof refueling tax control machine.)
1. A power circuit for an explosion-proof oiling tax control machine is characterized in that an overvoltage and overcurrent protection unit and a DC-DC voltage reduction circuit unit are used as independent power modules for injection molding and sealing, and a welding leg is reserved and welded on a board card; wherein, overvoltage overcurrent protection unit includes:
a voltage stabilizing diode V203, a resistor R206 and a resistor R207 which are sequentially connected with the power supply input end are grounded; the connection node of the resistor R206 and the resistor R207 is connected to the base electrode of the triode V204, the collector electrode of the triode V204 is connected to the base electrode of the triode V208, and the collector electrode of the triode V208 is connected to the source electrode of the high-power MOS transistor V207 through the resistor R214; the resistor R214 is connected in parallel between the base electrode and the emitter electrode of the triode V709, the collector electrode of the triode V709 is connected with the grid electrode of the high-power MOS tube V207, and the drain electrode of the high-power MOS tube V207 is used as a protection output end and is connected to the input end of the DC-DC step-down circuit unit.
2. The power supply circuit for the anti-explosion oil filling tax control machine according to claim 1, characterized in that when the voltage at the power input end is higher than the rated voltage value, the high-power MOS tube V207 through which the power output passes is cut off, and the power supply is turned off; when abnormal short circuit or large current is generated in the oiling tax control machine, the power output is cut off through a high-power MOS (metal oxide semiconductor) tube V207, and the power is turned off.
3. The power supply circuit for the anti-explosion fuel filling tax control machine as claimed in claim 1, wherein the transistors V204 and V208 are NPN transistors, and the transistor V709 is a PNP transistor.
4. The power supply circuit for the anti-explosion fuel filling tax control machine as claimed in claim 1, wherein the collector of each of the triode V204 and the triode V208 is connected to the power input end through a resistor, and the collector of the triode V709 is connected to the power input end through a capacitor; the collector of the triode V208 is connected to the connection node of the triode V709 and the capacitor through a zener diode V205, and the zener diode V205 is connected in parallel with a resistor R211.
5. The power supply circuit for the anti-explosion oil filling tax control machine according to claim 4, wherein the cathode of the zener diode V203 is connected to the power input end; the cathode of the voltage-stabilizing diode V205 is connected to the connection node of the triode V709 and the capacitor.
6. The power supply circuit for the anti-explosion fuel filling tax control machine as claimed in claim 1, wherein the power supply input overvoltage protection process comprises: when the external input power supply is higher than the rated voltage value, the voltage stabilizing diode V203 is conducted, the voltage difference part passing through the voltage stabilizing tube is divided by the resistors R206 and R207 to enable the triode V204 to be conducted, the triode V208 is cut off, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, the MOS tube V207 is cut off, and the rear-end control circuit is protected. When the input voltage is lower than the rated voltage value, the triode V204 is cut off, the base electrode of the triode V208 is divided into high voltage and conducted through the resistors R210 and R208, the base electrode of the high-power MOS tube V207 is lowered, the MOS tube V207 is conducted, and the circuit is electrified and works normally.
7. The power supply circuit for the anti-explosion oil filling tax control machine according to claim 1, wherein the overcurrent and short circuit abnormal protection process comprises: when the current of the internal circuit of the refueling tax control machine is overhigh or abnormally short-circuited, the resistor R214 generates a pressure difference, the voltage generated by the base electrode and the collector electrode meets the conduction condition, the triode V709 is conducted, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, and the MOS tube V207 is turned off, so that the whole circuit is protected. When the current of the internal circuit is normal, the voltage difference generated by the resistor R214 is small, the triode V709 is cut off and turned off, the base electrode of the high-power MOS tube V207 is changed into the original low level, the MOS tube V207 is turned on, and the circuit is electrified and works normally.
8. The power supply circuit for the anti-explosion fuel filling tax control machine according to claim 2, wherein the rated voltage is 16V.
9. An explosion-proof fuel filling tax control machine, characterized in that it comprises a power supply circuit according to any one of claims 1 to 8.
Technical Field
The invention relates to the technical field of an oil filling tax control machine, in particular to a power supply circuit for an explosion-proof oil filling tax control machine.
Background
At present, the oil filling tax control machine adopts 12V power supply, and the power is output to a DC-DC voltage reduction unit through an overvoltage protection unit and converted into 4V power to supply power to a control circuit. The power module units are directly designed on the board card, energy generated by the power module units of the power circuit is easily released to the outside, and when a short circuit or electric spark occurs on a circuit, flammable and explosive gas around the circuit is easily ignited, so that the standard requirement of the intrinsic safety circuit cannot be met. The standard requirement characteristics of the intrinsic safety circuit are as follows: the power supply circuit and the outlet are safe, both in normal operation and in fault conditions, and the spark produced does not ignite explosive mixtures in the surrounding environment.
And the overvoltage and overcurrent protection circuit of the refueling tax control machine in the power electronic industry can often use a thyristor, the thyristor can be damaged sometimes, and most of the thyristors are not perfect because overcurrent and overvoltage protection measures are not perfect, so that the overcurrent and overvoltage problem is not solved fundamentally.
Therefore, how to provide a power circuit for an explosion-proof fuel filling tax control machine, which has good explosion-proof performance and can effectively protect the power from overvoltage and overcurrent, is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
The invention provides a power supply circuit for an explosion-proof oil filling tax control machine aiming at the current research situation and the existing problems, which can better meet the explosion-proof requirement of the intrinsic safety circuit standard and can realize the power supply overvoltage and overcurrent protection of the explosion-proof oil filling tax control machine.
The invention provides a power supply circuit for an explosion-proof oiling tax control machine, wherein an overvoltage and overcurrent protection unit and a DC-DC voltage reduction circuit unit are used as independent power supply modules for injection molding and sealing, and a welding leg is reserved and welded on a board card; wherein, overvoltage overcurrent protection unit includes:
a voltage stabilizing diode V203, a resistor R206 and a resistor R207 which are sequentially connected with the power supply input end are grounded; the connection node of the resistor R206 and the resistor R207 is connected to the base electrode of the triode V204, the collector electrode of the triode V204 is connected to the base electrode of the triode V208, and the collector electrode of the triode V208 is connected to the source electrode of the high-power MOS transistor V207 through the resistor R214; the resistor R214 is connected in parallel between the base electrode and the emitter electrode of the triode V709, the collector electrode of the triode V709 is connected with the grid electrode of the high-power MOS tube V207, and the drain electrode of the high-power MOS tube V207 is used as a protection output end and is connected to the input end of the DC-DC step-down circuit unit.
Preferably, when the voltage at the input end of the power supply is higher than the rated voltage value, the high-power MOS tube V207 through which the power supply output passes is cut off, and the power supply is turned off; when abnormal short circuit or large current is generated in the oiling tax control machine, the power output is cut off through a high-power MOS (metal oxide semiconductor) tube V207, and the power is turned off.
Preferably, the triodes V204 and V208 are NPN triodes, and the triode V709 is a PNP triode.
Preferably, the collector electrodes of the triode V204 and the triode V208 are both connected to the power input end through a resistor, and the collector electrode of the triode V709 is connected to the power input end through a capacitor; the collector of the triode V208 is connected to the connection node of the triode V709 and the capacitor through a zener diode V205, and the zener diode V205 is connected in parallel with a resistor R211.
Preferably, the cathode of the voltage stabilizing diode V203 is connected to a power input terminal; the cathode of the voltage-stabilizing diode V205 is connected to the connection node of the triode V709 and the capacitor.
Preferably, the power input overvoltage protection process comprises: when the external input power supply is higher than the rated voltage value, the voltage stabilizing diode V203 is conducted, the voltage difference part passing through the voltage stabilizing tube is divided by the resistors R206 and R207 to enable the triode V204 to be conducted, the triode V208 is cut off, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, the MOS tube V207 is cut off, and the rear-end control circuit is protected. When the input voltage is lower than the rated voltage value, the triode V204 is cut off, the base electrode of the triode V208 is divided into high voltage and conducted through the resistors R210 and R208, the base electrode of the high-power MOS tube V207 is lowered, the MOS tube V207 is conducted, and the circuit is electrified and works normally.
Preferably, the overcurrent and short-circuit abnormality protection process includes: when the current of the internal circuit of the refueling tax control machine is overhigh or abnormally short-circuited, the resistor R214 generates a pressure difference, the voltage generated by the base electrode and the collector electrode meets the conduction condition, the triode V709 is conducted, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, and the MOS tube V207 is turned off, so that the whole circuit is protected. When the current of the internal circuit is normal, the voltage difference generated by the resistor R214 is small, the triode V709 is cut off and turned off, the base electrode of the high-power MOS tube V207 is changed into the original low level, the MOS tube V207 is turned on, and the circuit is electrified and works normally.
Preferably, the rated voltage is 16V.
The invention also provides an explosion-proof oil filling tax control machine which comprises the power circuit.
Compared with the prior art, the invention has the following beneficial effects:
the power supply circuit for the anti-explosion oil filling tax control machine is characterized in that the DC-DC voltage reduction unit and the overvoltage and overcurrent protection unit are injection-molded and sealed into a power supply module to prevent energy generated by the power supply circuit from being released to the outside, and the power supply circuit is safer than a power supply circuit designed on a board card alone and meets the design of an intrinsic safety circuit. Meanwhile, the invention provides a reliable and stable overvoltage and overcurrent protection circuit which prevents the board card from being burnt due to overhigh external voltage and the abnormity caused by internal short circuit so as to better meet the requirement of the intrinsic safety circuit.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only embodiments of the invention, and that for a person skilled in the art, other drawings can be obtained from the provided drawings without inventive effort.
FIG. 1 is a schematic diagram of a power supply framework of a fuel filling tax control machine according to an embodiment of the present invention;
fig. 2 is a circuit diagram of overvoltage and overcurrent protection of a power supply of the fuel filling tax control machine according to the embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to the attached drawing 1 in the specification, in the power circuit for the anti-explosion refueling tax control machine, the overvoltage and overcurrent protection unit and the DC-DC voltage reduction circuit unit are used as independent power modules for injection molding and sealing, and welding pins are reserved and welded on a board card, so that energy generated by the power circuit can be prevented from being released to the outside, and when a circuit is short-circuited or subjected to electric spark, surrounding flammable and explosive gas is easily ignited, and the anti-explosion effect is enhanced.
Referring to the attached drawing 2 of the specification, the overvoltage and overcurrent protection unit disclosed in this embodiment can perform overvoltage and overcurrent protection on the power supply of the tax-control oiling machine, and the specific circuit structure includes:
a voltage stabilizing diode V203, a resistor R206 and a resistor R207 which are sequentially connected with the power supply input end are grounded; the connection node of the resistor R206 and the resistor R207 is connected to the base electrode of the triode V204, the collector electrode of the triode V204 is connected to the base electrode of the triode V208, and the collector electrode of the triode V208 is connected to the source electrode of the high-power MOS transistor V207 through the resistor R214; the resistor R214 is connected in parallel between the base electrode and the emitter electrode of the triode V709, the collector electrode of the triode V709 is connected with the grid electrode of the high-power MOS tube V207, and the drain electrode of the high-power MOS tube V207 is used as a protection output end and is connected to the input end of the DC-DC step-down circuit unit. The collector electrodes of the triode V204 and the triode V208 are connected with the power input end through resistors, and the collector electrode of the triode V709 is connected with the power input end through a capacitor; the collector of the triode V208 is connected to the connection node of the triode V709 and the capacitor through the voltage stabilizing diode V205, and the voltage stabilizing diode V205 is connected with the resistor R211 in parallel. The negative electrode of the voltage stabilizing diode V203 is connected with the power supply input end; the cathode of the voltage-stabilizing diode V205 is connected to the connection node of the triode V709 and the capacitor. The triode V204 and the triode V208 are NPN triodes, and the triode V709 is a PNP triode.
The principle of realizing overvoltage and overcurrent protection is as follows: when the voltage of the input end of the power supply is higher than 16V, the high-power MOS tube V207 through which the power supply output passes is cut off, and the power supply is turned off; when abnormal short circuit or large current is generated in the oiling tax control machine, the power output is cut off through a high-power MOS (metal oxide semiconductor) tube V207, and the power is turned off.
The overvoltage and overcurrent protection unit is mainly divided into 2 parts: the power input overvoltage protection circuit part, the overcurrent and short circuit abnormity protection circuit part:
the power input overvoltage protection process comprises the following steps: when the external input power supply is higher than the value of 16V, the voltage stabilizing diode V203 is conducted, the voltage difference part passing through the voltage stabilizing tube is divided by the resistors R206 and R207 to enable the triode V204 to be conducted, the triode V208 is cut off, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, the MOS tube V207 is cut off, and the rear-end control circuit is protected. When the input voltage is lower than the value of 16V, the triode V204 is cut off, the base electrode of the triode V208 is divided into high voltage and conducted through the resistors R210 and R208, the base electrode of the high-power MOS tube V207 is lowered, the MOS tube V207 is conducted, and the circuit is electrified and works normally.
The overcurrent and short circuit abnormity protection process comprises the following steps: when the current of the internal circuit of the refueling tax control machine is overhigh or abnormally short-circuited, the resistor R214 generates a pressure difference, the voltage generated by the base electrode and the collector electrode meets the conduction condition, the triode V709 is conducted, the base electrode of the high-power MOS tube V207 is changed to be high and cut off, and the MOS tube V207 is turned off, so that the whole circuit is protected. When the current of the internal circuit is normal, the voltage difference generated by the resistor R214 is small, the triode V709 is cut off and turned off, the base electrode of the high-power MOS tube V207 is changed into the original low level, the MOS tube V207 is turned on, and the circuit is electrified and works normally.
The embodiment also discloses an explosion-proof refuelling tax control machine, including the power supply circuit of any one of the above-mentioned. The protection output end of the overvoltage and overcurrent protection unit is connected with the input end of the DC-DC voltage reduction unit to carry out voltage reduction operation and
The above detailed description is provided for the power circuit for the anti-explosion refueling tax control machine provided by the invention, and the principle and the implementation mode of the invention are explained by applying specific examples, and the description of the above examples is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
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