CN218603389U - Intrinsic safety power supply circuit for gas meter - Google Patents
Intrinsic safety power supply circuit for gas meter Download PDFInfo
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- CN218603389U CN218603389U CN202223221101.0U CN202223221101U CN218603389U CN 218603389 U CN218603389 U CN 218603389U CN 202223221101 U CN202223221101 U CN 202223221101U CN 218603389 U CN218603389 U CN 218603389U
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Abstract
The utility model discloses an intrinsically safe power supply circuit for a gas meter, which comprises an input protection unit, a lightning protection unit, an EMI filtering unit, an AC-DC unit, an output filtering unit and an output protection unit; the input end of the input protection unit is used as the input end of the power circuit and is used for connecting with commercial power; the output end of the input protection unit is sequentially connected with the lightning protection unit, the EMI filtering unit, the AC-DC unit, the output filtering unit and the overcurrent protection unit, and the output end of the overcurrent protection unit is used for supplying power to a load. Has the advantages that: the explosion-proof, flame-proof and lightning-proof effects are good, and the power supply signal is stable.
Description
Technical Field
The utility model belongs to the technical field of gas table power supply, concretely relates to essence safety power supply circuit for gas table.
Background
The basic principle of the intrinsic safety circuit is that electric explosion prevention is realized by limiting spark discharge energy and heat energy of the circuit, so that electric sparks and heat effects generated under normal working and specified fault states cannot ignite explosive mixtures in the surrounding environment.
For a gas meter, when a power supply circuit is designed, circuit designs such as fusing protection, alternating current-direct current conversion, filtering and the like need to be performed, but after a large number of electrical components are stacked and connected, weak sparks or sparks, smoke and the like are inevitably generated inside the gas meter. However, the gas meter has the function of metering combustible gas, the installation and working environment of the gas meter just belongs to flammable and explosive environments, and the dangerous technology is high.
In the design of a gas meter power supply applied to the intrinsic safety technology, the number of the existing technologies is small, and the special requirements and the use environment of the gas meter on the power supply need to be considered during the design, so that the intrinsic safety technology is necessarily combined to design the gas meter power supply in an adaptive manner.
SUMMERY OF THE UTILITY MODEL
To the not enough of above-mentioned prior art, the utility model aims to solve the technical problem that: how to provide an essence safety power supply circuit for gas table combines essence safety technology and gas table power supply circuit, improves the fire prevention blast resistant performance of gas table power supply circuit.
In order to solve the technical problem, the utility model adopts the following technical scheme:
an essential safety power supply circuit for a gas meter is characterized in that: the device comprises an input protection unit, a lightning protection unit, an EMI filtering unit, an AC-DC unit, an output filtering unit and an output protection unit;
the input end of the input protection unit is used as the input end of the power circuit and is used for being connected with commercial power; the output end of the input protection unit is sequentially connected with the lightning protection unit, the EMI filtering unit, the AC-DC unit, the output filtering unit and the overcurrent protection unit, and the output end of the overcurrent protection unit is used for supplying power to a load.
Through the design, the input protection circuit realizes the input end overvoltage and overcurrent protection. Because most gas meters are located outdoors, the power supply circuit design lightning protection unit effectively reduces the probability of damage to the gas meters after lightning stroke. Designing an EMI filtering unit to realize filtering; alternating current-direct current conversion is realized through an AC-DC unit; and the DC signal output by the AC-DC unit is subjected to filtering processing by combining with an output filtering unit. And an output protection unit is also arranged to perform overcurrent and overvoltage protection on the power load, so that the reliability of the power circuit is improved. The power supply circuit can be fundamentally prevented from accidents such as explosion, fire and the like through the special design of the units.
According to a further technical scheme, the input protection unit comprises a TRXF type fused rheostat RF, one end of the fused rheostat RF is used as a live wire L connecting end of the input end of the power circuit, and the other end of the fused rheostat RF is used for being connected with the lightning protection unit.
In the prior art, a self-recovery fuse is mostly adopted for overvoltage and overcurrent protection, so that fusing explosion can occur, smoke and sparks are not generated in the RF fusing process of the TRXF type fusing rheostat through the scheme, the probability of generating spark smoke in the gas meter is reduced, and the use safety performance of the gas meter is improved.
The further technical scheme is as follows: the lightning protection unit comprises three piezoresistors: the voltage-sensitive resistor comprises a first voltage-sensitive resistor RZ1, a second voltage-sensitive resistor RZ2 and a third voltage-sensitive resistor RZ3; one end of the first piezoresistor RZ1 is connected with the other end of the fuse rheostat RF, and the other end of the first piezoresistor RZ1 is connected with a zero line of a power input line; one end of the second piezoresistor RZ2 is connected with the other end of the fuse rheostat RF, the other end of the second piezoresistor RZ2 is connected with the cathode of a Schottky diode D5, and the anode of the Schottky diode D5 is grounded; and the common end of the second piezoresistor RZ2 and the Schottky diode D5 is connected with one end of the third piezoresistor RZ3, and the other end of the third piezoresistor RZ3 is used for connecting a zero line of a power input line.
By adopting the scheme, the lightning protection effect of the circuit is effectively improved.
The further technical scheme is as follows: the EMI filtering unit comprises a common-mode inductor L1, a first safety regulation X capacitor C10, a second safety regulation X capacitor C11, a first safety regulation Y capacitor C09 and a second safety regulation Y capacitor C12; the first safety gage X capacitor C10 is connected with the first piezoresistor RZ1 in parallel, the fourth pin end of the common mode inductor L1 is connected with the other end of the fuse rheostat RF, the second pin end of the common mode inductor L1 is connected with a zero line of a power input line, a second safety gage X capacitor C11 is connected between the first pin end of the common mode inductor L1 and the third pin end of the common mode inductor L1, the third pin end of the common mode inductor L1 is grounded through a first safety gage Y capacitor C9, and the first pin end of the common mode inductor L1 is grounded through a second safety gage Y capacitor C12.
By adopting the design, the inductor and the capacitor are combined to realize the filtering effect, and the subsequent signal quality is improved. Secondly, for high-power load equipment or some circuits with poor quality, after the power is pulled out, the plug is always electrified, namely residual voltage, differential mode interference and common mode interference can be removed by designing a safety capacitor, safety faults cannot occur after failure, and the residual voltage can be removed after the power is pulled out. In the scheme, an X capacitor is generally used in combination with a Y capacitor.
The further technical scheme is as follows: the AC-DC unit comprises a first chip U1, and the model of the first chip U1 is LS10-13BXXR3; the first pin of the first chip U1 is connected with the first pin end of the common-mode inductor L1, the second pin end of the first chip U1 is connected with the third pin end of the common-mode inductor L1, a starting capacitor C1 is connected between the third pin end and the fourth pin end of the first chip U1, the fourth pin end of the first chip U1 is grounded through a third safety Y capacitor C2, the fifth pin end of the first chip U1 is grounded and serves as the direct-current negative output end of the AC-DC unit, and the sixth pin end of the first chip U1 serves as the direct-current positive output end of the AC-DC unit.
By adopting the scheme, the LS10-13BXXR3 series is a high-efficiency green module power supply of a miniaturized bare board, and the power supply has the advantages of AC/DC dual-purpose, wide input voltage range, high reliability, low power consumption, safety isolation and the like. Based on the AC-DC conversion module, an isolation capacitor is arranged on the periphery of the AC-DC conversion module, and solid high-voltage isolation is realized. And the module has the function of output overvoltage and overcurrent protection, and the protection parameter point of the module is 6V,2A.
The further technical scheme is as follows: the output filtering unit comprises a differential mode inductor L1, one end of the differential mode inductor L1 is used for being connected with a direct current positive electrode output end of the AC-DC unit, one end of the differential mode inductor L1 is grounded through a third filtering capacitor C3 and a fifth filtering capacitor C5 respectively, and the other end of the differential mode inductor L1 is grounded through a fourth filtering capacitor C4 and a sixth capacitor C6 respectively; the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit, and the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit.
By adopting the scheme, the inductor and the capacitor are combined to filter the direct current output signal.
The further technical scheme is as follows: the output protection unit comprises a second chip U2, the model of the second chip U2 is PW1515, a fifth pin of the second chip U2 is connected with the filtering output end of the output filtering unit, a fifth pin of the second chip U2 is grounded through a capacitor C17, the fifth pin of the second chip U2 is grounded through a resistor R2 and a resistor R1 in sequence, the common end of the resistor R2 and the resistor R1 is connected with a fourth pin of the second chip U2, a third pin of the second chip U2 is grounded through a resistor R3, and a second pin of the second chip U2 is grounded.
The first pin end of the second chip U2 is grounded through a capacitor C15 and a capacitor C20 respectively, the first pin end of the second chip U2 is grounded through a rheostat D1, the first pin end of the second chip U2 is connected with the other end of a resistor R8 through a resistor R4, a fuse F1, a diode D2, a diode D3, a fuse F2 and a fuse F2 in sequence, and the other end of the resistor R8 is used as a load anode connecting end; the load circuit also comprises a load negative electrode connecting end which is grounded through a resistor R6.
By adopting the scheme, the edge circuits with the second chip U2 as the center are combined to form the secondary overvoltage and overcurrent protection circuit, and the overvoltage and overcurrent protection chip is adopted to carry out overvoltage and overcurrent protection design on the power supply of the electric load. And the protection parameter points can be programmatically adjusted. And a subsequent fuse is combined, and an overvoltage and overcurrent protection circuit is additionally arranged. And a current-limiting protection circuit is formed by combining R4, R8, R6, D2, D3, F1 and F2, and the current-limiting protection circuit can not cause overcurrent due to short circuit of load equipment.
The utility model discloses a theory of operation and beneficial effect are:
through the scheme, the intrinsic safety design is carried out based on the power supply requirement of the gas meter, smoke and spark are not generated in the process of RF fusing of the TRXF type fusing rheostat adopted by the input protection unit, the probability of generating the smoke of the spark in the gas meter is reduced, and the use safety performance of the gas meter is improved. The lightning protection unit adopts the piezoresistor to effectively improve the lightning protection effect of the circuit. Common mode inductance and safety capacitor in EMI filtering unit combine to realize the filtering action, promote follow-up signal quality. Differential mode interference and common mode interference can be removed by designing the safety capacitor, and residual voltage can be removed after power is removed without safety failure after failure. The AC-DC unit adopts LS10-13BXXR3 series as a module chip, and has wide input voltage range, high reliability, low power consumption and safe isolation. The output filtering unit filters the direct current output signal, so that the power supply is more stable. The output protection unit adopts an overvoltage and overcurrent protection chip to carry out overvoltage and overcurrent protection design on a power supply of an electric load. The gas meter is designed and prevented from the root problems by combining the use environment of the gas meter, so that the explosion or fire caused by a power circuit is effectively reduced or even avoided.
Drawings
FIG. 1 is a block diagram of the circuit of the present invention;
FIG. 2 is a first circuit diagram of a portion of the unit cell shown in FIG. 1;
FIG. 3 is a circuit diagram II of a portion of the unit shown in FIG. 1;
fig. 4 is a circuit diagram of the interface.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
In specific implementation, as shown in fig. 1 to 4:
an intrinsically safe power supply circuit for a gas meter is disclosed, and referring to fig. 1, the intrinsically safe power supply circuit comprises an input protection unit, a lightning protection unit, an EMI filtering unit, an AC-DC unit, an output filtering unit and an output protection unit which are connected in sequence; the input end of the input protection unit is used as the input end of the power circuit and is used for connecting with commercial power; the output end of the input protection unit is sequentially connected with the lightning protection unit, the EMI filtering unit, the AC-DC unit, the output filtering unit and the overcurrent protection unit, and the output end of the overcurrent protection unit is used for supplying power to a load.
As can be seen from fig. 2 in detail, the input protection unit includes a TRXF type fused varistor RF, one end of the fused varistor RF serves as a terminal of a live line L at the input end of the power circuit, and the other end of the fused varistor RF is connected to one end of a first varistor RZ1, one end of a second varistor RZ2, and a second pin end of a common mode inductor L1 of the EMI filter unit in the lightning protection unit.
In this embodiment, in the circuit debugging process, debugging resistors R9 are further connected in parallel at two RF ends of the TRXF type fused varistor, so as to implement the over-voltage and over-current fusing protection debugging design.
In this embodiment, referring to fig. 2, the lightning protection unit includes three piezoresistors, namely a first piezoresistor RZ1, a second piezoresistor RZ2, and a third piezoresistor RZ3; one end of the first piezoresistor RZ1 is connected with the other end of the fuse rheostat RF, and the other end of the first piezoresistor RZ1 is connected with a zero line of a power input line; one end of the second piezoresistor RZ2 is connected with the other end of the fuse rheostat RF, the other end of the second piezoresistor RZ2 is connected with the cathode of a Schottky diode D5, and the anode of the Schottky diode D5 is grounded; and the common end of the second piezoresistor RZ2 and the Schottky diode D5 is connected with one end of the third piezoresistor RZ3, and the other end of the third piezoresistor RZ3 is connected with a zero line of a power input circuit.
The EMI filtering unit comprises a common-mode inductor L1, a first safety X capacitor C10, a second safety X capacitor C11, a first safety Y capacitor C09 and a second safety Y capacitor C12;
as can be seen in fig. 2, the specific connection lines are: first ann rule X electric capacity C10 with first piezo-resistor RZ1 is parallelly connected, common mode inductance L1 fourth pin end with fusing rheostat RF's the other end is connected, common mode inductance L1 second pin end connects power input line's zero line, common mode inductance L1 first pin end with be connected with second ann rule X electric capacity C11 between the common mode inductance L1 third pin end, common mode inductance L1 third pin end is through first ann rule Y electric capacity C9 ground connection, common mode inductance L1 first pin end is through second ann rule Y electric capacity C12 ground connection.
The X capacitor and the Y capacitor are combined for use when the functions of filtering and residual voltage discharging are designed, the X capacitor is a large capacitor, and the Y capacitor is a small capacitor.
In this embodiment, the parameter of the first safety X capacitor C10 is 275V/0.1uF; the parameter of the second safety X capacitor C11 is 275V/0.1uF; the parameter of the first safety Y capacitor C9 is 2KV/1nF; the parameter of the second safety Y capacitor C12 is 2KV/1nF.
In the present embodiment, the AC-DC unit includes a first chip U1, and in the present embodiment, referring to fig. 2, the first chip U1 has a model number LS10-13B05R3, and its output signal is a 5V/2A direct current signal.
The first pin of the first chip U1 is connected with the first pin end of the common-mode inductor L1, the second pin end of the first chip U1 is connected with the third pin end of the common-mode inductor L1, a starting capacitor C1 is connected between the third pin end and the fourth pin end of the first chip U1, the fourth pin end of the first chip U1 is grounded through a third safety Y capacitor C2, the fifth pin end of the first chip U1 is grounded and serves as the direct-current negative output end of the AC-DC unit, and the sixth pin end of the first chip U1 serves as the direct-current positive output end of the AC-DC unit.
In the embodiment, the AC-DC unit has primary output overvoltage and overcurrent protection, and the protection point is 6V,2A.
Referring to fig. 2, the output filter unit includes a differential mode inductor L1, one end of the differential mode inductor L1 is used for connecting a direct current positive output end of the AC-DC unit, one end of the differential mode inductor L1 is further grounded through a third filter capacitor C3 and a fifth filter capacitor C5, respectively, and the other end of the differential mode inductor L1 is grounded through a fourth filter capacitor C4 and a sixth capacitor C6, respectively; the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit, and the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit.
Referring to fig. 3, the output protection unit includes a second chip U2, the model of the second chip U2 is PW1515, a fifth pin of the second chip U2 is connected to the filter output end of the output filter unit, a fifth pin of the second chip U2 is further grounded via a capacitor C17, the fifth pin of the second chip U2 is further grounded via a resistor R2 and a resistor R1 in sequence, a common end of the resistor R2 and the resistor R1 is connected to the fourth pin of the second chip U2, a third pin of the second chip U2 is grounded via a resistor R3, a second pin of the second chip U2 is grounded, a first pin of the second chip U2 is grounded via a capacitor C15 and a capacitor C20, respectively, a first pin of the second chip U2 is grounded via a varistor D1, and a first pin of the second chip U2 is further connected to the load connection end of the resistor R2-R8 as a load connection end after being connected to the fuse R4, a fuse F1, a diode D2, a fuse F2, a F2, and a fuse F2, and a resistor R8 in sequence; referring to fig. 3, it can also be seen that a load negative connection terminal P2-2 is further included, and the load negative connection terminal P2-2 is grounded via a resistor R6.
In this embodiment, the fuse protection current is 1A.
As can be seen in fig. 4 and 3, the first pin terminal Vout of the second chip U2 is connected to a load interface through an optical coupler U3, which is an optical coupler type EL816. This part is used for authentication.
The utility model discloses a theory of operation is:
when the power is on, the input end of the input protection unit is connected with the mains supply and is an electric signal of 220V/50 Hz. The electric signal L1 passes through an input protection unit and a lightning protection unit, and then is filtered by an EMI filtering unit to obtain an input filtering signal L2, the input filtering signal L2 passes through an AC-DC unit to convert an alternating current signal into a direct current output signal L3 of 5V/2A, the direct current output signal L3 is filtered by an output filtering unit to obtain an output filtering signal L4, and the output filtering signal L4 is subjected to overvoltage and overcurrent protection by an output protection unit and then is supplied to an electric load.
In the embodiment, the overcurrent protection unit has three places, the first place is that the AC-DC unit has primary output overvoltage and overcurrent protection, and the threshold value of a protection point is 6V and 2A. The second point is an overvoltage and overcurrent protection circuit externally arranged on the PW1515 chip, and the protection point is programmable. The third point is an output fuse at the rear end, and the protection current threshold is 1A.
The above are only preferred embodiments of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the technical scope of the present invention, and the technical scope of the present invention should be considered to fall within the scope of the claims.
Claims (7)
1. An intrinsically safe power supply circuit for a gas meter, characterized in that: the device comprises an input protection unit, a lightning protection unit, an EMI filtering unit, an AC-DC unit, an output filtering unit and an output protection unit;
the input end of the input protection unit is used as the input end of the power circuit and is used for being connected with commercial power; the output end of the input protection unit is sequentially connected with the lightning protection unit, the EMI filtering unit, the AC-DC unit, the output filtering unit and the overcurrent protection unit, and the output end of the overcurrent protection unit is used for supplying power to a load.
2. The intrinsically safe power supply circuit for a gas meter of claim 1, wherein: the input protection unit comprises a TRXF type fusing rheostat RF, one end of the fusing rheostat RF is used as a live wire L connecting end of the input end of the power circuit, and the other end of the fusing rheostat RF is used for being connected with the lightning protection unit.
3. An intrinsically safe power supply circuit for a gas meter as claimed in claim 2, wherein: the lightning protection unit comprises three piezoresistors: the voltage-sensitive resistor comprises a first voltage-sensitive resistor RZ1, a second voltage-sensitive resistor RZ2 and a third voltage-sensitive resistor RZ3;
one end of the first piezoresistor RZ1 is connected with the other end of the fuse rheostat RF, and the other end of the first piezoresistor RZ1 is connected with a zero line of a power input line;
one end of the second piezoresistor RZ2 is connected with the other end of the fuse rheostat RF, the other end of the second piezoresistor RZ2 is connected with the cathode of a Schottky diode D5, and the anode of the Schottky diode D5 is grounded;
and the common end of the second piezoresistor RZ2 and the Schottky diode D5 is connected with one end of the third piezoresistor RZ3, and the other end of the third piezoresistor RZ3 is used for connecting a zero line of a power input line.
4. An intrinsically safe power supply circuit for a gas meter as claimed in claim 3, wherein: the EMI filtering unit comprises a common-mode inductor L1, a first safety X capacitor C10, a second safety X capacitor C11, a first safety Y capacitor C09 and a second safety Y capacitor C12;
the first safety gage X capacitor C10 is connected with the first piezoresistor RZ1 in parallel, the fourth pin end of the common mode inductor L1 is connected with the other end of the fuse rheostat RF, the second pin end of the common mode inductor L1 is connected with a zero line of a power input line, a second safety gage X capacitor C11 is connected between the first pin end of the common mode inductor L1 and the third pin end of the common mode inductor L1, the third pin end of the common mode inductor L1 is grounded through a first safety gage Y capacitor C9, and the first pin end of the common mode inductor L1 is grounded through a second safety gage Y capacitor C12.
5. The intrinsically safe power supply circuit for a gas meter of claim 4, wherein: the AC-DC unit comprises a first chip U1, and the model of the first chip U1 is LS10-13BXXR3;
the first pin of the first chip U1 is connected with the first pin end of the common mode inductor L1, the second pin end of the first chip U1 is connected with the third pin end of the common mode inductor L1, a starting capacitor C1 is connected between the third pin end and the fourth pin end of the first chip U1, the fourth pin end of the first chip U1 is grounded through a third safety gauge Y capacitor C2, the fifth pin end of the first chip U1 is grounded and serves as the direct current negative output end of the AC-DC unit, and the sixth pin end of the first chip U1 serves as the direct current positive output end of the AC-DC unit.
6. The intrinsically safe power supply circuit for a gas meter of claim 5, wherein:
the output filtering unit comprises a differential mode inductor L1, one end of the differential mode inductor L1 is used for being connected with a direct current positive electrode output end of the AC-DC unit, one end of the differential mode inductor L1 is grounded through a third filtering capacitor C3 and a fifth filtering capacitor C5 respectively, and the other end of the differential mode inductor L1 is grounded through a fourth filtering capacitor C4 and a sixth capacitor C6 respectively; the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit, and the other end of the differential mode inductor L1 is used as a filtering output end of the output filtering unit.
7. An intrinsically safe power supply circuit for a gas meter as claimed in claim 6, wherein: the output protection unit comprises a second chip U2, the model of the second chip U2 is PW1515, a fifth pin of the second chip U2 is connected with the filter output end of the output filter unit, a fifth pin of the second chip U2 is grounded through a capacitor C17, a fifth pin of the second chip U2 is grounded through a resistor R2 and a resistor R1 in sequence, a common end of the resistor R2 and the resistor R1 is connected with a fourth pin of the second chip U2, a third pin of the second chip U2 is grounded through a resistor R3, a second pin of the second chip U2 is grounded, a first pin of the second chip U2 is grounded through a capacitor C15 and a capacitor C20 respectively, a first pin of the second chip U2 is grounded through a rheostat D1, and a first pin of the second chip U2 is connected with the other end of a resistor R8 as a load connection end after being connected with a resistor R4, a fuse F1, a diode D2, a fuse D3, a fuse F2 and a resistor R2 through a resistor R8 in sequence;
the load circuit also comprises a load negative electrode connecting end which is grounded through a resistor R6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223221101.0U CN218603389U (en) | 2022-12-02 | 2022-12-02 | Intrinsic safety power supply circuit for gas meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223221101.0U CN218603389U (en) | 2022-12-02 | 2022-12-02 | Intrinsic safety power supply circuit for gas meter |
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| CN218603389U true CN218603389U (en) | 2023-03-10 |
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| CN202223221101.0U Active CN218603389U (en) | 2022-12-02 | 2022-12-02 | Intrinsic safety power supply circuit for gas meter |
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- 2022-12-02 CN CN202223221101.0U patent/CN218603389U/en active Active
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