Reverse connection prevention circuit of gas meter and gas meter

Abstract

The utility model relates to the technical field of intelligent gas meters, in particular to an anti-reverse-connection circuit of a gas meter and the gas meter. According to the circuit, each power supply in a plurality of power supplies is provided with a corresponding switch circuit and a control circuit, and the control circuit of each power supply is connected with the corresponding switch circuit; each power supply is connected with the load through the corresponding switching circuit and supplies power to the load; the control circuit controls the corresponding switching circuit to be switched on according to a first signal of a corresponding current power supply, the control circuit is further used for controlling the corresponding switching circuit to be switched off according to a second signal of the current power supply, the direction of the first signal is from the current power supply to the load, and the direction of the second signal is opposite to the direction of the first signal; the control circuit controls the corresponding switching circuit to be cut off according to a third signal of the other power supply, and the third signal is generated through the voltage difference between the other power supply and the current power supply. According to the circuit, the situation that the circuit board in the intelligent gas meter is damaged due to reverse connection of the battery is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of smart gas meters, and further to a gas meter reverse connection prevention circuit and a gas meter. Background Art

[0002] Smart gas meters are powered by multiple power sources, such as multiple dry cells and lithium batteries. However, during the use of smart gas meters, the batteries may be reversely connected, causing damage to the circuit board in the smart gas meter; and the high-voltage battery may reversely charge the low-voltage battery, causing damage to the low-voltage battery. Utility Model Content

[0003] In order to solve the above technical problems, the present application provides a gas meter anti-reverse connection circuit and a gas meter, which avoids the reverse connection of the battery and causes damage to the circuit board in the smart gas meter.

[0004] In the first aspect, the present application provides a reverse connection protection circuit for a gas meter, comprising: a load; multiple power supplies, each of the multiple power supplies is provided with a corresponding switching circuit and a control circuit, and the control circuit of each power supply is connected to the corresponding switching circuit; each power supply is connected to the load through the corresponding switching circuit to supply power to the load; the control circuit is used to control the corresponding switching circuit to be turned on according to a first signal of the corresponding current power supply, and the control circuit is also used to control the corresponding switching circuit to be turned off according to a second signal of the current power supply, wherein the direction of the first signal is from the current power supply to the load, and the direction of the second signal is opposite to the direction of the first signal; the control circuit is also used to control the corresponding switching circuit to be turned off according to a third signal of other power supplies, and the third signal is generated by the voltage difference between the other power supplies and the current power supply.

[0005] The anti-reverse connection circuit of the above gas meter works in parallel with multiple power supplies. Even if a power supply fails, other power supplies can continue to supply power to the load, thereby improving the power supply reliability of the entire system. Each power supply is equipped with an independent control circuit and switch circuit. The control circuit controls the conduction and cutoff of the switch circuit to avoid the situation where the power supply is reversely connected and the circuit board in the smart gas meter is damaged, or the high-voltage power supply reversely charges the low-voltage power supply, causing damage to the low-voltage power supply.

[0006] In one implementation, the multiple power sources are respectively multiple first batteries and second batteries, the multiple first batteries are provided with corresponding first control circuits and first switch circuits, and the second batteries are provided with corresponding second control circuits and second switch circuits.

[0007] In one implementation, the first switching circuit is a first MOS tube, and the first control circuit includes: a first triode, a second triode, a first resistor and a second resistor; the drain of the first MOS tube is connected to the positive electrodes of the multiple first batteries through the first interface of the gas meter, and the source of the first MOS tube is connected to the emitter of the second triode; the emitter of the first triode is connected to the drain of the first MOS tube, and the base of the first triode is connected to the base of the second triode; one end of the first resistor is respectively connected to the collector of the first triode and the base of the first triode, and the other end is grounded; one end of the second resistor is respectively connected to the collector of the second triode and the gate of the first MOS tube, and the other end is grounded.

[0008] The anti-reverse connection circuit of the above gas meter controls the conduction and cutoff of the first MOS tube through the cooperation between the first transistor and the second transistor, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the first MOS tube is used as a switch for conduction and cutoff, so that when multiple first batteries work normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency.

[0009] In one implementation, the second switch circuit is a second MOS tube, and the second control circuit includes: a third triode, a fourth triode, a third resistor and a fourth resistor; the drain of the second MOS tube is connected to the positive electrode of the second battery through the second interface of the gas meter, and the source of the second MOS tube is connected to the emitter of the fourth triode; the emitter of the third triode is connected to the drain of the second MOS tube, and the base of the third triode is connected to the base of the fourth triode; one end of the third resistor is respectively connected to the collector of the third triode and the base of the third triode, and the other end is grounded; one end of the fourth resistor is respectively connected to the collector of the fourth triode and the gate of the second MOS tube, and the other end is grounded.

[0010] The anti-reverse connection circuit of the above gas meter controls the conduction and cutoff of the second MOS tube through the cooperation of the third transistor and the fourth transistor, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the second MOS tube is used as a switch for conduction and cutoff, so that when the second battery works normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency.

[0011] In one implementation, when the plurality of first batteries are reversely connected or the second battery charges the plurality of first batteries, the first transistor is turned off and the second transistor is turned on, so as to control the first MOS transistor to be turned off.

[0012] In one implementation, when the second battery is reversely connected or the plurality of first batteries charge the second battery, the third transistor is turned off and the fourth transistor is turned on to control the second MOS transistor to be turned off.

[0013] In one implementation, the plurality of first batteries are dry cells, and the second batteries are lithium batteries.

[0014] In one implementation, it further includes: a dry cell power-off detection circuit, wherein the dry cell power-off detection circuit is connected to the positive electrodes of the plurality of first batteries through the first interface.

[0015] In one implementation, the dry cell power-off detection circuit includes: a fifth resistor, a sixth resistor and a voltage detection chip; one end of the fifth resistor is connected to the positive poles of the multiple first batteries through the first interface, and the other end is connected to the voltage detection chip; one end of the sixth resistor is connected to the voltage detection chip, and the other end is grounded.

[0016] In one implementation, the first MOS transistor and the second MOS transistor are both PMOS transistors, and the first transistor, the second transistor, the third transistor and the fourth transistor are all PNP transistors.

[0017] In a second aspect, the present application also provides a gas meter, comprising any one of the above-mentioned anti-reverse connection circuits of the gas meter.

[0018] Compared with the prior art, the utility model has at least one of the following beneficial effects:

[0019] 1. Through multiple power supplies working in parallel, even if one power supply fails, other power supplies can continue to supply power to the load, thereby improving the power supply reliability of the entire system. Each power supply is equipped with an independent control circuit and switch circuit. The control circuit controls the conduction and cutoff of the switch circuit to avoid the situation where the circuit board in the smart gas meter is damaged due to reverse connection of the power supply, or the situation where the high-voltage power supply reversely charges the low-voltage power supply, causing damage to the low-voltage power supply.

[0020] 2. The first triode and the second triode cooperate with each other to control the on and off of the first MOS tube, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the first MOS tube is used as a switch for on and off, so that when multiple first batteries work normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency.

[0021] 3. The third transistor and the fourth transistor cooperate with each other to control the conduction and cutoff of the second MOS tube, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the second MOS tube is used as a switch for conduction and cutoff, so that when the second battery works normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present utility model.

[0023] Figure 1 A schematic structural diagram of a reverse connection protection circuit of a gas meter provided in an embodiment of the present application is shown;

[0024] Figure 2 A schematic structural diagram of a reverse connection protection circuit of a gas meter provided in an embodiment of the present application is shown;

[0025] Figure 3 A schematic structural diagram of a reverse connection protection circuit of a gas meter provided in an embodiment of the present application is shown;

[0026] Figure 4 A schematic structural diagram of an anti-reverse connection circuit for a gas meter provided in an embodiment of the present application is shown.

[0027] Description of Figure Numbers:

[0028] A plurality of first batteries 100 ; a second battery 200 ; a gas meter 300 ; a power supply 400 ; a switch circuit 500 ; a control circuit 600 ; a first switch circuit 310 ; a first control circuit 320 ; a second switch circuit 330 ; a second control circuit 340 ; a load 350 ; a dry cell power-off detection circuit 360 ; and a voltage detection chip 361 . DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0030] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0031] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0032] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0033] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0034] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications should also be regarded as the protection scope of the utility model.

[0035] Smart gas meters are highly integrated intelligent metering devices that use advanced sensor technology, microelectronics technology, and wireless communication technology to accurately measure the amount of gas used by users. Compared with traditional mechanical gas meters, smart gas meters not only improve the accuracy and reliability of measurement, but also have advanced functions such as remote automatic meter reading, real-time monitoring of gas usage, remote control of valve opening and closing, and helping users optimize gas usage through data analysis.

[0036] The reverse connection protection circuit of the smart gas meter is a key part of its design, which ensures the safety and stability of the gas meter when it is powered by batteries. Since smart gas meters are usually powered by a combination of dry batteries and lithium batteries, the correct connection of battery polarity is essential to protect the circuit and extend battery life.

[0037] The reverse connection protection circuit ensures that the current can only flow in the correct direction by using electronic components such as diodes, transistors or MOSFETs. When the battery is connected correctly, the reverse connection protection circuit is turned on, allowing the current to flow smoothly with almost no additional voltage loss; when the battery is connected in reverse, the circuit is turned off, preventing the current from flowing, thereby protecting the gas meter circuit from damage.

[0038] The following is a description with reference to the accompanying drawings:

[0039] Reference Figure 1 , which shows a schematic diagram of the structure of a gas meter anti-reverse connection circuit provided in an embodiment of the present application, such as Figure 1 As shown, it includes: a load 350; multiple power supplies 400, each of the multiple power supplies 400 is provided with a corresponding switching circuit 500 and a control circuit 600, and the control circuit 500 of each power supply is connected to the corresponding switching circuit 600; each power supply 400 is connected to the load 350 through the corresponding switching circuit 500 to supply power to the load 350; the control circuit 600 is used to control the corresponding switching circuit 500 to be turned on according to the first signal of the corresponding current power supply 400, and the control circuit 600 is also used to control the corresponding switching circuit 500 to be turned off according to the second signal of the current power supply 400, wherein the direction of the first signal is from the current power supply 400 to the load 350, and the direction of the second signal is opposite to the direction of the first signal; the control circuit 600 is also used to control the corresponding switching circuit 500 to be turned off according to the third signal of other power supplies 400, and the third signal is generated by the voltage difference between the other power supplies 400 and the current power supply 400.

[0040] In the embodiment of the present application, when any control circuit 600 receives the first signal (the first signal can be current) of the current power supply 400 corresponding to the control circuit 600, it indicates that the current power supply 400 is positively connected and normally supplies power to the load 350. At this time, the control circuit 600 corresponding to the current power supply 400 will control the switch circuit 500 corresponding to the current power supply 400 to be turned on; when any control circuit 600 receives the second signal (the second signal can be current) of the current power supply 400 corresponding to the control circuit 600, it indicates that the current power supply 400 is reversely connected and the current power supply 400 is reversely charged. At this time, the control circuit 600 corresponding to the current power supply 400 will control the switch circuit 500 corresponding to the current power supply 400 to be turned off to prevent the current power supply from being reversely charged and causing damage to the power supply.

[0041] When there is a voltage difference between the current power source 400 corresponding to any control circuit 600 and the other power sources 400, the current power source 400 will be reversely charged by the other power sources 400. At this time, the control circuit 600 will receive the third signal (the third signal can be a current) transmitted by the other power sources 400, and then the control circuit 600 corresponding to the current power source 400 will control the switch circuit 500 corresponding to the current power source 400 to be cut off, so as to prevent the current power source from being reversely charged and causing damage to the power source.

[0042] In the embodiment of the present application, multiple power supplies work in parallel, so even if a power supply fails, other power supplies can continue to supply power to the load, thereby improving the power supply reliability of the entire system. Each power supply is equipped with an independent control circuit and a switch circuit. The control circuit controls the conduction and cutoff of the switch circuit to avoid the situation where the power supply is reversely connected, causing damage to the circuit board in the smart gas meter, or the high-voltage power supply reversely charges the low-voltage power supply, causing damage to the low-voltage power supply.

[0043] Reference Figure 2 , which shows a schematic diagram of the structure of a gas meter anti-reverse connection circuit provided in an embodiment of the present application, such as Figure 2 As shown, it includes: a first diode D1, a second diode D2, a plurality of first batteries 100, a second battery 200, a gas meter 300, and a load 350. The anode of the first diode D1 is connected to the positive electrodes of the plurality of first batteries 100 through the first interface J1 of the gas meter 300, and the cathode of the first triode D1 is connected to the load 350. The anode of the second triode D2 is connected to the positive electrode of the second battery 200 through the second interface J2 of the gas meter 300, and the cathode of the second triode D2 is connected to the load 350.

[0044] When the plurality of first batteries 100 and the second batteries 200 are forward connected, the first diode D1 and the second diode D2 are both turned on, and current flows out from the plurality of first batteries 100 and the second battery 200 respectively, and flows into the load 350 through the first diode D1 and the second diode D2 to supply power.

[0045] When the first batteries 100 and / or the second batteries 200 are reversely connected, the first diode D1 and / or the second diode D2 are cut off to prevent the current from flowing in the first batteries 100 and / or the second batteries 200 in reverse, thereby protecting the circuit and the battery of the gas meter (the gas meter in the embodiment of the present application is a smart gas meter) from being damaged. In addition to using diodes as a way to implement the anti-reverse connection circuit, the embodiment of the present application can also realize the function of the anti-reverse connection circuit through the cooperation of transistors, MOS tubes, MOS tubes and triodes, and the cooperation of multiple circuits.

[0046] The embodiment of the present application provides a reverse connection protection circuit for a gas meter, wherein the multiple power sources are multiple first batteries and second batteries, the multiple first batteries are provided with corresponding first control circuits and first switch circuits, and the second batteries are provided with corresponding second control circuits and second switch circuits.

[0047] Please refer to the following Figure 3 The invention is described in detail, which shows a schematic diagram of the structure of a gas meter reverse connection protection circuit provided in an embodiment of the present application, including: a plurality of first batteries 100, a second battery 200, a gas meter 300, a first switch circuit 310, a first control circuit 320, a second switch circuit 330 and a second control circuit 340. Among them, the first switch circuit 310, the first control circuit 320, the second switch circuit 330 and the second control circuit 340 are all arranged inside the gas meter 300; the first switch circuit 310 is connected to the positive poles of the multiple first batteries 100 through the first interface J1 of the gas meter 300, and the first switch circuit 310 is connected to the second switch circuit 330; the second switch circuit 330 is connected to the positive pole of the second battery 200 through the second interface J2 of the gas meter 300; the first control circuit 320 is connected in parallel with the first switch circuit 310, and when the multiple first batteries 100 are reversely connected or the second battery 200 charges the multiple first batteries 100, the first control circuit 320 controls the first switch circuit 310 to be cut off; the second control circuit 340 is connected in parallel with the second switch circuit 330, and when the second battery 200 is reversely connected or the multiple first batteries 100 are charged to the second battery 200, the second control circuit 340 controls the second switch circuit 330 to be cut off.

[0048] When the plurality of first batteries 100 and the second batteries 200 are operating normally, the first control circuit 320 controls the first switch circuit 310 to be turned on, the second control circuit 340 controls the second switch circuit 330 to be turned on, and no current flows through the first control circuit 320 and the second control circuit 340. The current flows out from the plurality of first batteries 100 and the second battery 200, respectively flows through the first switch circuit 310 and the second switch circuit 330 through the first interface J1 and the second interface J2, and finally flows into the load 350 for power supply.

[0049] When multiple first batteries 100 are reversely connected or the voltage of multiple first batteries 100 is lower than the voltage of the second battery 200, if multiple first batteries 100 are charged by reverse current, the first control circuit 320 controls the first switch circuit 310 to be cut off, and the first control circuit 320 is also in the cut-off state to prevent the current from flowing in the reverse direction through the first switch circuit 310 into the multiple first batteries 100, causing damage to the first batteries 100 and damage to the internal circuit board of the smart gas meter.

[0050] When the second battery 200 is reversely connected or the voltage of the second battery 200 is lower than the voltage of the first batteries 100, if the second battery 200 is reversely charged, the second control circuit 340 controls the second switch circuit 330 to be cut off, and the second control circuit 340 is also in the cut-off state to prevent the current from flowing into the second battery 200 through the second switch circuit 330 in reverse.

[0051] In the embodiment of the present application, the first control circuit and the second control circuit are used to realize the conduction and cutoff of the first switch circuit and the second switch circuit, thereby avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter and the reverse charging of the small voltage battery by the large voltage battery, causing damage to the small voltage battery.

[0052] Reference Figure 4 , which shows a schematic diagram of the structure of a gas meter anti-reverse connection circuit provided in an embodiment of the present application, such as Figure 4 As shown, the first switch circuit 310 is a first MOS transistor Q1, and the first control circuit 320 includes: a first triode Q2, a second triode Q3, a first resistor R1 and a second resistor R2; the drain of the first MOS transistor Q1 is connected to the positive electrodes of the plurality of first batteries 100 through the first interface J1 of the gas meter 300, and the source of the first MOS transistor Q1 is connected to the emitter of the second triode Q3; the emitter of the first triode Q2 is connected to the drain of the first MOS transistor Q1, and the base of the first triode Q2 is connected to the base of the second triode Q3; one end of the first resistor R1 is respectively connected to the collector of the first triode Q2 and the base of the first triode Q3, and the other end is grounded; one end of the second resistor R2 is respectively connected to the collector of the second triode Q3 and the gate of the first MOS transistor Q1, and the other end is grounded.

[0053] In the embodiment of the present application, when the multiple first batteries 100 are working normally (i.e., the first batteries 100 are positively connected and not reversely charged), the multiple first batteries 100 flow into the emitter of the first transistor Q2 through the first interface J1, and the voltage of the emitter of the first transistor Q2 is greater than the base voltage, and the first transistor Q2 is turned on at this time. The first resistor R1 is used to limit the current between the collector and the base of the first transistor Q2, and the current between the collector and the emitter of the first transistor Q2. Because the first transistor Q2 is in the on state, the voltage between the collector and the emitter of the first transistor Q2 is approximately 0V, and the voltage on the first resistor R1 is the input voltage of the multiple first batteries 100. The voltage at the emitter of the second transistor Q3 is approximately the input voltage of the first battery 100, so the second transistor Q3 is turned off. At this time, the source voltage of the first MOS tube Q1 is approximately equal to the input voltage of the plurality of first batteries 100, the gate voltage of the first MOS tube Q1 is pulled down to 0V by the second resistor R2, and the source voltage of the first MOS tube Q1 is greater than the gate voltage, so Q1 is turned on.

[0054] Therefore, when the multiple first batteries 100 work normally, current flows out of the multiple first batteries 100 and is divided into two paths after passing through the first interface J1. One path of current flows into the load 350 through the first MOS transistor Q1 to supply power; the other path of current flows through the first transistor Q2, the first resistor R1, and then is grounded.

[0055] When the plurality of first batteries 100 are reversely connected or reversely charged by the second battery 200, the emitter voltage of the second transistor Q3 is greater than the base voltage, and the second transistor Q3 is turned on. The first resistor R1 is used to limit the current between the collector and the base of the second transistor Q3; the second resistor R2 is used to limit the current between the collector and the emitter of the second transistor Q3. Because the second transistor Q3 is in the on state, the voltage between the emitter and the collector of the second transistor Q3 is approximately 0V, and the voltage on the second resistor R2 is the input voltage of the reverse current. That is, the gate and source voltages of the first MOS tube Q1 are equal, and the first MOS tube Q1 is turned off; the emitter voltage of the first transistor Q2 is less than the base voltage, so Q2 is turned off.

[0056] Therefore, when the multiple first batteries 100 are reversely connected or reversely charged by the second battery 200, the first MOS tube Q1 is turned off, the first transistor Q2 is turned off, and only the second transistor Q3 and the second resistor R2 have current, and the reverse current cannot flow into the multiple first batteries 100.

[0057] The embodiment of the present application controls the conduction and cutoff of the first MOS tube by the cooperation between the first triode and the second triode, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the first MOS tube is used as a switch for conduction and cutoff, so that when multiple first batteries are working normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency.

[0058] In one embodiment of the present application, the second switch circuit 330 and the second control circuit 340 may also use a combination of a MOS tube and a triode to achieve the function of reverse connection prevention. Figure 4The embodiment of the present application also provides a reverse connection protection circuit for a gas meter, wherein the second switch circuit 330 is a second MOS tube Q4, and the second control circuit 340 includes: a third transistor Q5, a fourth transistor Q6, a third resistor R3 and a fourth resistor R4; the drain of the second MOS tube Q4 is connected to the positive electrode of the second battery 200 through the second interface J2 of the gas meter 300, and the source of the second MOS tube Q4 is connected to the emitter of the fourth transistor Q6; the emitter of the third transistor Q5 is connected to the drain of the second MOS tube Q4, and the base of the third transistor Q5 is connected to the base of the fourth transistor Q6; one end of the third resistor R3 is respectively connected to the collector of the third transistor Q5 and the base of the third transistor Q5, and the other end is grounded; one end of the fourth resistor R4 is respectively connected to the collector of the fourth transistor Q6 and the gate of the second MOS tube Q4, and the other end is grounded.

[0059] In the embodiment of the present application, when the second battery 200 is working normally (i.e., the second battery 200 is positively connected and not reversely charged), the second battery 200 flows into the emitter of the third triode Q5 through the second interface J2, and the voltage of the emitter of the third triode Q5 is greater than the base voltage, and the third triode Q5 is turned on at this time. The third resistor R3 is used to limit the current between the collector and the base of the third triode Q5, and the current between the collector and the emitter of the third triode Q5. Because the third triode Q5 is in the on state, the voltage between the collector and the emitter of the third triode Q5 is approximately 0V, and the voltage on the third resistor R3 is the input voltage of the second battery 200. The voltage at the emitter of the fourth triode Q6 is approximately the input voltage of the second battery 200, so the fourth triode Q6 is turned off. At this time, the source voltage of the second MOS tube Q4 is approximately equal to the input voltage of the second battery 200, the gate voltage of the second MOS tube Q4 is pulled down to 0V by the fourth resistor R4, and the source voltage of the second MOS tube Q4 is greater than the gate voltage, so the second MOS tube Q4 is turned on.

[0060] Therefore, when the second battery 200 is working normally, current flows out of the second battery 200 and is divided into two paths after passing through the second interface J2. One path of current flows into the load 350 through the second MOS transistor Q4 to supply power; the other path of current flows through the third transistor Q5, the third resistor R3, and then is grounded.

[0061] When the second battery 200 is reversely connected or reversely charged by multiple first batteries 100, the emitter voltage of the fourth transistor Q6 is greater than the base voltage, and the fourth transistor Q6 is turned on. The third resistor R3 is used to limit the current between the collector and the base of the fourth transistor Q6; the fourth resistor R4 is used to limit the current between the collector and the emitter of the fourth transistor Q6. Because the fourth transistor Q6 is in the on state, the voltage between the emitter and the collector of the fourth transistor Q6 is approximately 0V, and the voltage on the fourth resistor R4 is the input voltage of the reverse current. That is, the gate and source voltages of the second MOS tube Q4 are equal, and the second MOS tube Q4 is turned off; the emitter voltage of the third transistor Q5 is less than the base voltage, so the third transistor Q5 is turned off.

[0062] Therefore, when the second battery 200 is reversely connected or reversely charged by multiple first batteries 100, the second MOS tube Q4 is turned off, the third transistor Q5 is turned off, and only the fourth transistor Q6 and the fourth resistor R4 have current, and the reverse current cannot flow into the second battery 200.

[0063] The embodiment of the present application controls the conduction and cutoff of the second MOS tube by the cooperation between the third transistor and the fourth transistor, further avoiding the reverse connection of the battery, which may cause damage to the circuit board in the smart gas meter. At the same time, the second MOS tube is used as a switch for conduction and cutoff, so that when the second battery is working normally, the input voltage can be input to the load without loss for power supply, thereby improving the power supply efficiency.

[0064] In some embodiments of the present application, the plurality of first batteries are dry batteries, and the second batteries are lithium batteries.

[0065] The first batteries are 4 No. 5 dry batteries with a rated voltage of 6V and a theoretically usable voltage range of 4.5V-6V; the lithium battery is a primary lithium sub-battery with a rated voltage of 3.6V and a theoretically usable voltage range of 3.0V-3.6V. Of course, the first battery in the embodiment of the present application can also be an alkaline dry battery, a zinc-carbon dry battery, a lithium battery dry battery, a silver oxide battery, etc. The second battery can be a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, a lithium cobalt oxide battery, a lithium manganese oxide battery, a lithium nickel manganese cobalt oxide battery, etc. At the same time, the number of the first battery and the second battery can also be adjusted according to the actual situation, and is not limited here.

[0066] In some embodiments of the present application, refer to the attached Figure 4, and further includes: a dry battery power-off detection circuit 360, which is connected to the positive electrodes of the plurality of first batteries 100 through the first interface J1. The dry battery power-off detection circuit 360 includes: a fifth resistor R5, a sixth resistor R6, and a voltage detection chip 361; one end of the fifth resistor R5 is connected to the positive electrodes of the plurality of first batteries 100 through the first interface J1, and the other end is connected to the voltage detection chip 361; one end of the sixth resistor R6 is connected to the voltage detection chip 361, and the other end is grounded.

[0067] The voltage detection chip 361 is used to detect the voltage of the plurality of first batteries 100. When the plurality of first batteries 100 are removed, the voltage detection chip 361 can detect this event and report it to the user through the gas meter for processing. The fifth resistor R5 and the sixth resistor R6 play the role of current limiting and voltage dividing to prevent excessive current from damaging the voltage detection chip 361.

[0068] In some embodiments of the present application, the first MOS transistor Q1 and the second MOS transistor Q4 are both PMOS transistors, and the first transistor Q2, the second transistor Q3, the third transistor Q5 and the fourth transistor Q6 are all PNP transistors. The load 350 can be a controller logic control circuit, a sensor, a display unit, a communication module, a valve control unit, a data storage unit, a power conversion and management system, an auxiliary system, a test and diagnosis circuit, etc.

[0069] An embodiment of the present application also provides a gas meter, comprising the anti-reverse connection circuit of the gas meter described in any of the above embodiments.

[0070] An embodiment of the present application also provides an electronic device, comprising the anti-reverse connection circuit of the gas meter described in any of the above embodiments.

[0071] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred implementations of the utility model. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications should also be regarded as the protection scope of the utility model.

Claims

1. A gas meter anti-reverse connection circuit, characterized in that: include: load; A plurality of power supplies, each of the plurality of power supplies is provided with a corresponding switch circuit and a control circuit, and the control circuit of each power supply is connected to the corresponding switch circuit; Each of the power sources is connected to the load through the corresponding switch circuit to supply power to the load; The control circuit is used to control the corresponding switch circuit to be turned on according to a first signal of the corresponding current power supply, and the control circuit is also used to control the corresponding switch circuit to be turned off according to a second signal of the current power supply, wherein the direction of the first signal is from the current power supply to the load, and the direction of the second signal is opposite to the direction of the first signal; The control circuit is further used to control the corresponding switch circuit to be turned off according to a third signal of the other power source, wherein the third signal is generated by a voltage difference between the other power source and the current power source.

2. The anti-reverse connection circuit of the gas meter according to claim 1, characterized in that: The multiple power sources are respectively multiple first batteries and second batteries. The multiple first batteries are provided with corresponding first control circuits and first switch circuits, and the second batteries are provided with corresponding second control circuits and second switch circuits.

3. The anti-reverse connection circuit of the gas meter according to claim 2, characterized in that: The first switch circuit is a first MOS tube, and the first control circuit includes: A first triode, a second triode, a first resistor and a second resistor; The drain of the first MOS tube is connected to the positive electrodes of the plurality of first batteries through the first interface of the gas meter, and the source of the first MOS tube is connected to the emitter of the second transistor; The emitter of the first transistor is connected to the drain of the first MOS transistor, and the base of the first transistor is connected to the base of the second transistor; One end of the first resistor is respectively connected to the collector of the first transistor and the base of the first transistor, and the other end is grounded; One end of the second resistor is respectively connected to the collector of the second transistor and the gate of the first MOS transistor, and the other end is grounded.

4. The anti-reverse connection circuit of the gas meter according to claim 3, characterized in that: The second switch circuit is a second MOS tube, and the second control circuit includes: a third triode, a fourth triode, a third resistor and a fourth resistor; The drain of the second MOS tube is connected to the positive electrode of the second battery through the second interface of the gas meter, and the source of the second MOS tube is connected to the emitter of the fourth transistor; The emitter of the third transistor is connected to the drain of the second MOS transistor, and the base of the third transistor is connected to the base of the fourth transistor; One end of the third resistor is respectively connected to the collector of the third transistor and the base of the third transistor, and the other end is grounded; One end of the fourth resistor is respectively connected to the collector of the fourth transistor and the gate of the second MOS transistor, and the other end is grounded.

5. The anti-reverse connection circuit of the gas meter according to claim 3 or 4, characterized in that: When the plurality of first batteries are reversely connected or the second battery charges the plurality of first batteries, the first transistor is turned off and the second transistor is turned on, so as to control the first MOS transistor to be turned off.

6. The anti-reverse connection circuit of the gas meter according to claim 4, characterized in that: When the second battery is reversely connected or the plurality of first batteries charge the second battery, the third transistor is turned off and the fourth transistor is turned on, so as to control the second MOS transistor to be turned off.

7. The anti-reverse connection circuit of the gas meter according to claim 6, characterized in that: Also includes: A dry cell power-off detection circuit is connected to the positive electrodes of the plurality of first batteries through the first interface.

8. The anti-reverse connection circuit of the gas meter according to claim 7, characterized in that: The dry cell power failure detection circuit comprises: A fifth resistor, a sixth resistor and a voltage detection chip; One end of the fifth resistor is connected to the positive electrodes of the plurality of first batteries through the first interface, and the other end is connected to the voltage detection chip; One end of the sixth resistor is connected to the voltage detection chip, and the other end is grounded.

9. The anti-reverse connection circuit of the gas meter according to claim 8, characterized in that: The first MOS tube and the second MOS tube are both PMOS tubes, and the first triode, the second triode, the third triode and the fourth triode are all PNP triodes.

10. A gas meter, characterized in that: A gas meter reverse connection prevention circuit comprising the circuit described in any one of claims 1 to 9.

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