Automatic power supply switching system and method based on gas furnace

Abstract

The present invention discloses an automatic power supply switching system and method based on a gas furnace, belonging to the field of household appliance safety technology. The system comprises: a J1 battery interface, wherein the J1 battery interface is used to connect a backup power supply; a J2 DC power supply interface, wherein the J2 DC power supply interface is used to connect a main power supply; a J3 output port, wherein the J3 output port is used to provide a power supply voltage to the gas furnace; and a voltage switching module, wherein the voltage switching module is used to automatically switch according to the power supply states of the J1 battery interface and the J2 DC power supply interface, so as to selectively supply power from the J1 battery interface or the J2 DC power supply interface to the J3 output port. The present invention effectively avoids the problem of port floating voltage during the power supply switching process, reduces the risk of gas fire, and improves safety.

Description

Technical Field

[0001] The invention relates to an automatic power supply switching system and method based on a gas furnace, belonging to the technical field of household appliance safety. Background Art

[0002] Gas explosion problems occur frequently, and how to reduce the risk has been a problem for many home appliance manufacturers. In order to solve this problem, many engineering and technical personnel have designed various solutions and made many attempts, which have achieved certain results, but are still not perfect. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide an automatic power supply switching system and method based on a gas furnace, which effectively avoids the problem of port floating voltage during power supply switching, reduces the risk of gas fire, and improves safety.

[0004] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0005] In a first aspect, the present invention provides an automatic power supply switching system based on a gas furnace, comprising:

[0006] J1 battery interface, the J1 battery interface is used to connect a backup power supply;

[0007] J2 DC power supply interface, the J2 DC power supply interface is used to connect the main power supply;

[0008] J3 output port, the J3 output port is used to provide power supply voltage to the gas furnace;

[0009] A voltage switching module, the voltage switching module is used to automatically switch according to the power status of the J1 battery interface and the J2 DC power supply interface to selectively supply power from the J1 battery interface or the J2 DC power supply interface to the J3 output port.

[0010] Further, the voltage switching module includes: Q2, Q3 PMOS tubes, R5 resistor, DF1 voltage regulator diode, R8, R4 resistors, Q4, Q1 NPN transistors, D4, D2 voltage regulator diodes, D1, D6 diodes, R2, R1 resistors;

[0011] One end of the D6 diode is connected to the J2 DC power supply interface, and the other end is connected to the 5, 6, 7, and 8 interfaces of the Q3PMOS tube. The 1, 2, and 3 interfaces of the Q3PMOS tube are connected to the DF1 voltage regulator diode. The 4 interface of the Q3PMOS tube is connected to the R8 resistor. The other end of the R8 resistor is connected to the 3 interface of the Q4NPN transistor. The 1 interface of the Q4NPN transistor is connected to the R4 resistor, and the 2 interface is connected to the D4 voltage regulator diode. The other end of the D4 voltage regulator diode is connected to the R4 resistor. One end of the R4 resistor is respectively connected to the R2 resistor and the 3 interface of the Q1NPN transistor. The 1 interface of the Q1NPN transistor is connected to the R1 resistor, and the 2 interface is connected to the D2 voltage regulator diode. The other end of the D2 voltage regulator diode is connected to the R1 resistor. The other end of the R1 resistor is connected to the DC-12V voltage. The other end of the R2 resistor is connected to the D1 diode, and the other end of the D1 diode is connected to the VBAT-12V voltage.

[0012] The 5, 6, 7, and 8 interfaces of the Q2PMOS tube are connected to the J1 battery interface, the 1, 2, and 3 interfaces of the Q2PMOS tube are connected to the R5 resistor, and the 4 interface of the Q2PMOS tube is respectively connected to the R5 resistor, the DF1 voltage regulator diode, and the common end of the Q3PMOS tube and the R8 resistor;

[0013] The interfaces 5, 6, 7, and 8 of the Q3 PMOS tube are also connected to the J3 output port.

[0014] Furthermore, the system also includes: a resistor R7 and a power indicator LED1. After the resistor R7 and the power indicator LED1 are connected in series, one end of the resistor R7 and the power indicator LED1 is grounded, and the other end is connected to the common end of the J3 output port and the Q3 PMOS tube.

[0015] Furthermore, when the J1 battery interface is connected to a 12V battery as a backup power supply, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode, the Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode, and the voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface, and the voltage passes through the R7 resistor and enters the power indicator LED1, the power indicator LED1 lights up, and at this time the floating voltage of the J2 DC power supply interface is lower than 1V.

[0016] Furthermore, when the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a suspended state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J3 output port is powered by the J2 DC power supply interface voltage through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

[0017] Furthermore, when the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, thereby maintaining the stable operation of the gas furnace.

[0018] In a second aspect, the present invention provides a gas furnace-based automatic power supply switching method, which is applicable to any of the aforementioned gas furnace-based automatic power supply switching systems, and the method comprises:

[0019] When the J1 battery interface is connected to a 12V battery as a backup power source, the J3 output port is powered by the J1 battery interface through the voltage division of the D1 diode, the R2 and R4 resistors, and the conduction of the Q4 NPN transistor;

[0020] When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the J3 output port is switched to be powered by the J2 DC power supply interface through the voltage division of the R1 resistor and the D2 voltage regulator diode and the conduction of the Q1 NPN transistor;

[0021] When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q4 NPN transistor is turned on again and the voltage of the Q3 PMOS tube is restored, so that the J3 output port is restored to be powered by the J1 interface, maintaining the stable operation of the gas furnace.

[0022] Furthermore, when the J1 battery interface is connected to a 12V battery as a backup power supply, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode, the Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode, and the voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface, and the voltage passes through the R7 resistor and enters the power indicator LED1, the power indicator LED1 lights up, and at this time the floating voltage of the J2 DC power supply interface is lower than 1V.

[0023] Furthermore, when the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a suspended state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J3 output port is powered by the J2 DC power supply interface voltage through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

[0024] Furthermore, when the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, thereby maintaining the stable operation of the gas furnace.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention provides an automatic power supply switching system and method based on a gas furnace. The J1 battery interface is used for battery power supply and the J2 DC power supply interface is used for DC12V power supply, which can realize seamless switching, effectively avoiding the problem of port floating voltage during power supply switching, reducing the risk of gas fire and improving safety;

[0027] 2. The present invention provides an automatic power supply switching system and method based on a gas furnace, which can ensure that the floating voltage of the port is lower than 1V during the switching process, avoid the generation of sparks, reduce the risk of gas fire, and improve safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1The invention discloses a circuit diagram of an automatic power supply switching system based on a gas furnace. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0030] Embodiment 1, as Figure 1 As shown, this embodiment introduces an automatic power supply switching system based on a gas furnace, including: a J1 battery interface, the J1 battery interface is used to connect a backup power supply; a J2 DC power supply interface, the J2 DC power supply interface is used to connect a main power supply; a J3 output port, the J3 output port is used to provide a power supply voltage to the gas furnace; a voltage switching module, the voltage switching module is used to automatically switch according to the power status of the J1 battery interface and the J2 DC power supply interface, so as to selectively supply power from the J1 battery interface or the J2 DC power supply interface to the J3 output port. The voltage switching module includes: Q2, Q3 PMOS tubes, R5 resistor, DF1 voltage regulator diode, R8, R4 resistors, Q4, Q1 NPN transistors, D4, D2 voltage regulator diodes, D1, D6 diodes, R2, R1 resistors; one end of the D6 diode is connected to J2 A DC power supply interface, one end of which is connected to interfaces 5, 6, 7, and 8 of the Q3PMOS tube, interfaces 1, 2, and 3 of the Q3PMOS tube are connected to the DF1 voltage regulator diode, interface 4 of the Q3PMOS tube is connected to the R8 resistor, the other end of the R8 resistor is connected to interface 3 of the Q4NPN transistor, interface 1 of the Q4NPN transistor is connected to the R4 resistor, interface 2 is connected to the D4 voltage regulator diode, the other end of the D4 voltage regulator diode is connected to the R4 resistor, a section of the R4 resistor is respectively connected to interfaces 3 of the R2 resistor and the Q1NPN transistor, interface 1 of the Q1NPN transistor is connected to the R1 resistor, interface 2 is connected to the D2 voltage regulator diode, the other end of the D2 voltage regulator diode is connected to the R1 resistor, and the other end of the R1 resistor is connected DC-12V voltage, the other end of the R2 resistor is connected to the D1 diode, and the other end of the D1 diode is connected to the VBAT-12V voltage; the 5, 6, 7, and 8 interfaces of the Q2PMOS tube are connected to the J1 battery interface, the 1, 2, and 3 interfaces of the Q2PMOS tube are connected to the R5 resistor, and the 4 interface of the Q2PMOS tube is respectively connected to the R5 resistor, the DF1 voltage regulator diode, and the common end of the Q3PMOS tube and the R8 resistor; the 5, 6, 7, and 8 interfaces of the Q3PMOS tube are also connected to the J3 output port; the system also includes: a resistor R7 and a power indicator LED1, after the resistor R7 and the power indicator LED1 are connected in series, one end is grounded, and the other end is connected to the J3 output port and the common end of the Q3PMOS tube.

[0031] The switching method of the automatic power supply switching system based on the gas furnace provided in this embodiment is as follows:

[0032] Step 1: When the J1 battery interface is connected to a 12V battery as a backup power source, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode. The Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode. The voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface. The voltage passes through the R7 resistor and enters the power indicator LED1. The power indicator LED1 lights up, and at this time, the floating voltage of the J2 DC power supply interface is lower than 1V.

[0033] Step 2: When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a suspended state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J2 DC power supply interface voltage supplies power to the J3 output port through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

[0034] Step 3: When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, and the power indicator LED1 lights up, keeping the gas furnace running stably.

[0035] The above three steps show that the battery power supply of J1 battery interface and the DC12V power supply of J2 DC power interface can achieve seamless switching, and can ensure that the floating voltage of the port is lower than 1V during the switching process, avoiding the generation of sparks, reducing the risk of gas fire, and improving safety.

[0036] Embodiment 2: This embodiment provides an automatic power supply switching method based on a gas furnace, which is applicable to the automatic power supply switching system based on a gas furnace described in any one of Embodiment 1. The method comprises:

[0037] When the J1 battery interface is connected to a 12V battery as a backup power source, the J3 output port is powered by the J1 battery interface through the voltage division of the D1 diode, the R2 and R4 resistors, and the conduction of the Q4 NPN transistor;

[0038] When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the J3 output port is switched to be powered by the J2 DC power supply interface through the voltage division of the R1 resistor and the D2 voltage regulator diode and the conduction of the Q1 NPN transistor;

[0039] When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q4 NPN transistor is turned on again and the voltage of the Q3 PMOS tube is restored, so that the J3 output port is restored to be powered by the J1 interface, maintaining the stable operation of the gas furnace.

[0040] Specifically, when the J1 battery interface is connected to a 12V battery as a backup power supply, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode, the Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode, and the voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface, and the voltage passes through the R7 resistor and enters the power indicator LED1, the power indicator LED1 lights up, and at this time the floating voltage of the J2 DC power supply interface is lower than 1V.

[0041] Specifically, when the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a suspended state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J3 output port is powered by the J2 DC power supply interface voltage through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

[0042] Specifically, when the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, thereby maintaining the stable operation of the gas furnace.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An automatic power supply switching system based on a gas furnace, characterized in that: include: J1 battery interface, the J1 battery interface is used to connect a backup power supply; J2 DC power supply interface, the J2 DC power supply interface is used to connect the main power supply; J3 output port, the J3 output port is used to provide power supply voltage to the gas furnace; A voltage switching module, the voltage switching module is used to automatically switch according to the power status of the J1 battery interface and the J2 DC power supply interface to selectively supply power from the J1 battery interface or the J2 DC power supply interface to the J3 output port.

2. The automatic power supply switching system based on a gas furnace according to claim 1 is characterized in that: The voltage switching module includes: Q2, Q3 PMOS tubes, R5 resistor, DF1 voltage regulator diode, R8, R4 resistors, Q4, Q1 NPN transistors, D4, D2 voltage regulator diodes, D1, D6 diodes, R2, R1 resistors; One end of the D6 diode is connected to the J2 DC power supply interface, and the other end is connected to the 5, 6, 7, and 8 interfaces of the Q3PMOS tube. The 1, 2, and 3 interfaces of the Q3PMOS tube are connected to the DF1 voltage regulator diode. The 4 interface of the Q3PMOS tube is connected to the R8 resistor. The other end of the R8 resistor is connected to the 3 interface of the Q4NPN transistor. The 1 interface of the Q4NPN transistor is connected to the R4 resistor, and the 2 interface is connected to the D4 voltage regulator diode. The other end of the D4 voltage regulator diode is connected to the R4 resistor. One end of the R4 resistor is respectively connected to the R2 resistor and the 3 interface of the Q1NPN transistor. The 1 interface of the Q1NPN transistor is connected to the R1 resistor, and the 2 interface is connected to the D2 voltage regulator diode. The other end of the D2 voltage regulator diode is connected to the R1 resistor. The other end of the R1 resistor is connected to the DC-12V voltage. The other end of the R2 resistor is connected to the D1 diode, and the other end of the D1 diode is connected to the VBAT-12V voltage. The 5, 6, 7, and 8 interfaces of the Q2PMOS tube are connected to the J1 battery interface, the 1, 2, and 3 interfaces of the Q2PMOS tube are connected to the R5 resistor, and the 4 interface of the Q2PMOS tube is respectively connected to the R5 resistor, the DF1 voltage regulator diode, and the common end of the Q3PMOS tube and the R8 resistor; The interfaces 5, 6, 7, and 8 of the Q3 PMOS tube are also connected to the J3 output port.

3. The automatic power supply switching system based on a gas furnace according to claim 2 is characterized in that: The system further comprises: a resistor R7 and a power indicator LED1. After the resistor R7 and the power indicator LED1 are connected in series, one end of the resistor R7 and the power indicator LED1 are grounded, and the other end is connected to the common end of the J3 output port and the Q3 PMOS tube.

4. The automatic power supply switching system based on a gas furnace according to claim 3 is characterized in that: When the J1 battery interface is connected to a 12V battery as a backup power source, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode, the Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode. The voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface, and the voltage enters the power indicator LED1 after passing through the R7 resistor. The power indicator LED1 lights up, and at this time, the floating voltage of the J2 DC power supply interface is lower than 1V.

5. The automatic power supply switching system based on a gas furnace according to claim 3 is characterized in that: When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a floating state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J2 DC power supply interface voltage supplies power to the J3 output port through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

6. The automatic power supply switching system based on a gas furnace according to claim 3, characterized in that: When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, maintaining the stable operation of the gas furnace.

7. A gas furnace-based automatic power supply switching method, applicable to the gas furnace-based automatic power supply switching system according to claim 3, characterized in that: The method comprises: When the J1 battery interface is connected to a 12V battery as a backup power source, the J3 output port is powered by the J1 battery interface through the voltage division of the D1 diode, the R2 and R4 resistors, and the conduction of the Q4NPN transistor; When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the J3 output port is switched to be powered by the J2 DC power supply interface through the voltage division of the R1 resistor and the D2 voltage regulator diode and the conduction of the Q1 NPN transistor; When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q4 NPN transistor is turned on again and the voltage of the Q3 PMOS tube is restored, so that the J3 output port is restored to be powered by the J1 interface, maintaining the stable operation of the gas furnace.

8. The automatic power supply switching method based on a gas furnace according to claim 7, characterized in that: When the J1 battery interface is connected to a 12V battery as a backup power source, the voltage of the Q4 NPN transistor passes through the D1 diode, R2 and R4 resistors, and reaches the conduction condition under the action of the D4 voltage regulator diode, the Q4 NPN transistor is turned on, and the R8 resistor is connected to the ground; the J1 battery interface is turned on through the Q2 PMOS tube, and the voltage passes through the R5 resistor and the DF1 voltage regulator diode. The voltage across the DF1 voltage regulator diode is clamped to 10V. At this time, the voltage of the Q3 PMOS tube is 12V, and the Q3 PMOS tube is turned on, so that the J3 output port is powered by the 1 battery interface, and the voltage enters the power indicator LED1 after passing through the R7 resistor. The power indicator LED1 lights up, and at this time, the floating voltage of the J2 DC power supply interface is lower than 1V.

9. The automatic power supply switching method based on a gas furnace according to claim 7, characterized in that: When the J2 DC power supply interface is connected to a DC12V power supply as the main power supply, the voltage of the Q1 NPN transistor reaches the conduction condition through the R1 resistor and the D2 Zener diode, the Q1 NPN transistor is turned on, the R4 resistor and the D4 Zener diode are short-circuited, at this time the Q4 NPN transistor is not turned on, and the R8 resistor is in a floating state; the voltage across the Zener diode DF1 and the resistor R5 is 0V, and the Q3 PMOS tube is not turned on; at this time the J1 battery interface power supply circuit is cut off, and the J2 DC power supply interface voltage supplies power to the J3 output port through the D6 diode, the power indicator LED1 is on, and at this time the floating voltage of the J1 battery interface is lower than 1V.

10. The automatic power supply switching method based on a gas furnace according to claim 7, characterized in that: When the DC12V power supply of the J2 DC power supply interface is unplugged, the Q1 NPN transistor is not turned on, and the voltage of the Q4 NPN transistor is input through VBAT-12V. Through the re-conduction of the Q4NPN transistor and the recovery of the voltage of the Q3PMOS tube, the J3 output port is restored to be powered by the J1 interface, maintaining the stable operation of the gas furnace.

Images