Circuit capable of automatically adapting to alternating current 110V and 220V power supply input

Abstract

The utility model relates to a circuit capable of automatically adapting to alternating current 110V and 220V power supply input. The circuit comprises a soft start control module and a voltage identification module, the input end of the soft start control module is connected with commercial power, and the output end is connected with the input end of the voltage identification module; the output end of the voltage identification module is connected to a primary coil of an external isolation transformer; the soft start control module comprises a piezoresistor and a time delay relay; the voltage identification module comprises a voltage dividing assembly and a determination assembly. According to the circuit capable of automatically adapting to alternating current 110V and 220V power supply input, the problem that equipment is damaged or tripped due to impact current when the equipment is just powered on can be effectively solved, and the safety of the equipment is improved; moreover, the device can automatically adapt to the input of ac.110V and ac.220V power supplies, improves the compatibility of the device with voltage, and can solve the surge problem generated by an isolation transformer.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medical devices, and particularly relates to a circuit automatically adapting to AC 110V and 220V power input. BACKGROUND

[0002] In order to ensure the safe use of the equipment and inhibit the transmission of high-frequency noise into the control loop, many medical equipment designs often use an isolation transformer when designing the power supply circuit. The main function of the isolation transformer is to completely insulate the primary side from the secondary side of the transformer, so that the electrical circuit of the equipment is completely isolated from the main power supply circuit of the power grid. At this time, the isolation transformer makes the secondary side floating, and the ground capacitance current of the system is small enough to cause no harm to the human body, so that the electrical use of the equipment becomes safer. Furthermore, since the core of the isolation transformer has the characteristics of high-frequency loss, it can inhibit the transmission of high-frequency noise into the main control loop of the equipment side.

[0003] The voltage standards of the power grid are different in different countries. The voltage standard in North America is 120V, 60Hz, which is designated by the United States and Canada and widely used in the two countries; the voltage standard in Japan is 100V, 50Hz or 60Hz; the voltage standard in South Korea is 220V, 60Hz; and the voltage standard in India is 230V, 50Hz.

[0004] Based on the above reasons, the following problems need to be solved when designing the equipment:

[0005] 1. Due to the use of the isolation transformer, the starting current is often very high, even 6-10 times the running current, so the starting current of the equipment when it is powered on can easily cause damage to the equipment or affect the load of the power grid, leading to tripping and affecting the normal work of other equipment. Therefore, the problem of soft start of the equipment needs to be solved.

[0006] 2. Due to various reasons such as cost, the electrical components integrated in the designed medical equipment system are not all capable of supporting 100-240V / AC wide voltage input, and many electrical components can only support 220V / AC voltage range power supply, resulting in the need for the equipment to specially solve the problem of 110V / AC voltage range power supply. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the shortcomings of the above-mentioned technology and provide a circuit that automatically adapts to AC 110V and AC 220V power input and has a soft start function.

[0008] In order to solve the above technical problems, the technical scheme provided by the present application is: an automatic adaptive circuit of AC 110V and 220V power input, comprising: a soft start control module and a voltage identification module; the input end of the soft start control module is connected to the mains, and the output end is connected to the input end of the voltage identification module; the output end of the voltage identification module is connected to the primary coil of an external isolation transformer; the soft start control module comprises a voltage-dependent resistor and a delay relay; the voltage-dependent resistor is connected in series between the input end and the output end of the soft start control module; the contact group of the delay relay is also connected in series between the input end and the output end of the soft start control module; the coil of the delay relay is powered by the mains connected to the input end of the soft start control module; the voltage identification module comprises a voltage division component and a judgment component; the voltage division component sends the input voltage to the judgment component after voltage division; the judgment component also inputs a standard voltage; the judgment component controls a switching relay; the common contact of the switching relay is connected to the output end of the soft start control module; the two output contacts of the switching relay are respectively connected to the 110V and 220V connectors in the primary coil of the external isolation transformer.

[0009] The further improvement of the above scheme is that: the normally open contact of the switching relay is connected to the 110V connector in the primary coil of the external isolation transformer, and the normally closed contact is connected to the 220V connector in the primary coil of the external isolation transformer.

[0010] The further improvement of the above scheme is that: the voltage identification module comprises a rectifier component, the input of the rectifier component is connected to the output of the soft start control module, and the rectified voltage is sent to the voltage division component.

[0011] The further improvement of the above scheme is that: the voltage division component is two groups of voltage division resistors, the two groups of voltage division resistors are connected in series, the middle node is used as the output, and the two ends are respectively connected to the two levels of the output end of the rectifier component.

[0012] The automatic adaptive circuit of AC 110V and 220V power input provided by the present application can effectively solve the problem of device damage or tripping due to impact current when the device is powered on, improve the safety of the device, and automatically adapt to the input of ac.110V and ac.220V power supply, improve the compatibility of the device to voltage, and solve the surge problem caused by the isolation transformer. The present application uses a relatively simple and mature circuit scheme, which is easy to apply in various devices. BRIEF DESCRIPTION OF DRAWINGS

[0013] The present application will be further described below with reference to the accompanying drawings.

[0014] Figure 1 is a structure schematic diagram of a preferred embodiment of the present application.

[0015] Figure 2 is Figure 1 a circuit diagram of the soft start control module in the

[0016] Figure 3 is Figure 1 a circuit diagram of the voltage identification module in the

[0017] Figure 4 is a schematic diagram of the isolation transformer structure. DETAILED DESCRIPTION

[0018] The circuit of the automatic adaptation of AC 110V and 220V power input of the embodiment, as shown in Figure 1 , includes: a soft start control module and a voltage identification module; the input end of the soft start control module is connected to the mains, and the output end is connected to the input end of the voltage identification module; the output end of the voltage identification module is connected to the primary coil of the external isolation transformer.

[0019] As shown in Figure 2 , the soft start control module includes a voltage-dependent resistor and a time-delay relay K2; the voltage-dependent resistor is connected in series between the input end and the output end of the soft start control module; the contact group of the time-delay relay K2 is also connected in series between the input end and the output end of the soft start control module; in the embodiment, an array formed by a total of 8 voltage-dependent resistors RT1 to RT8 is used, so that the resistance value of the voltage-dependent resistor array is smaller, and the power provided is higher. After the mains power supply input, it is also connected to the rectifier U1 through the fuse F1 and the resistor R24; the rectifier U1 and the subsequent circuit rectify and stabilize the input AC to DC 24V, which is supplied to the time-delay relay K2 and other parts requiring DC power supply. In the moment of starting power-on of the device, because of the existence of the isolation transformer, a large inrush current is generated, which is limited by the voltage-dependent resistor in the embodiment, and after a period of time, the device works stably, the time-delay relay K2 is attracted, and the device is stably powered through the time-delay relay K2.

[0020] As shown in Figure 3As shown, the voltage identification module includes a voltage division assembly and a determination assembly. After the mains power supply input, through resistance R1 and capacitor CX1, the voltage is divided and input to the voltage division assembly; after rectification to direct current by U3 in the voltage division assembly, the direct current is filtered by capacitor C4, and then divided by resistance R13 to R20, a total of 8 resistances, and sent to the determination assembly; the determination assembly is an operational amplifier U4A, the voltage division point of resistance R20 is input to the inverting input terminal of the operational amplifier U4A, and the non-inverting input terminal of the operational amplifier U4A is connected to a standard voltage. The standard voltage is 24V DC in the soft start control module, which is divided by resistances R21 and R22. The output terminal of the operational amplifier U4A drives a switching relay K1 through a subsequent circuit. In this way, according to the size of the input power supply, the switching relay K1 is allowed to act or not. When the input is ac.220V, the inverting input terminal of the operational amplifier U4A is higher than the non-inverting input terminal, and the switching relay K1 does not act; when the input is ac.110V, the inverting input terminal of the operational amplifier U4A is lower than the non-inverting input terminal, and the switching relay K1 acts.

[0021] The common contact of the switching relay K1 is connected to the output end of the soft start control module. The normally open contact of the switching relay K1 is connected to the 110V terminal in the primary coil of the external isolation transformer, and the normally closed contact is connected to the 220V terminal in the primary coil of the external isolation transformer. Thus, a single fault protection circuit is formed.

[0022] The single fault protection circuit is mainly used to avoid the risk that the switching relay K1 cannot be switched to the correct position due to incorrect identification of the power supply voltage caused by a single fault. Figure 4 As shown, the isolation transformer adopts a center tap, and the ac.110V power supply or the ac.220V power supply is connected to the corresponding output line of the primary input end of the isolation transformer. The secondary output end of the isolation transformer can output a stable ac.220V power supply to provide power to the internal load of the whole machine. Since the ac.110V output line of the primary input end of the isolation transformer, if the ac.220V voltage is supplied by mistake, will cause damage to the rear-end load circuit of the whole machine, therefore, when the single fault protection circuit identifies that the power supply is ac.220V voltage, the switching relay K1 is in an open state, and the ac.110V power supply supply path is cut off, so as to achieve the purpose of single fault state protection.

[0023] The present application is not limited to the above-mentioned embodiments. Any technical solution formed by equivalent replacement falls within the scope of protection required by the present application.

Claims

1. A circuit for automatically adapting to AC 110V and 220V power input, characterized in that, The utility model relates to a soft start control module and voltage identification module, the input of the soft start control module is connected with the commercial power, and the output is connected with the input of the voltage identification module, the output of the voltage identification module is connected with the primary coil of the external isolation transformer, the soft start control module includes the voltage-dependent resistor and the time delay relay, the voltage-dependent resistor is connected in series between the input and the output of the soft start control module, the contact group of the time delay relay is also connected in series between the input and the output of the soft start control module, the coil of the time delay relay is powered by the commercial power connected with the input of the soft start control module, the voltage identification module includes the voltage division component and the determination component, the voltage division component sends the voltage after voltage division to the determination component, the determination component also inputs the standard voltage, the determination component controls the switching relay, the common contact of the switching relay is connected with the output of the soft start control module, and the two output contacts of the switching relay are connected with the 110V connector and the 220V connector in the primary coil of the external isolation transformer respectively. The normally open contact of the switching relay is connected with the 110V connector in the primary coil of the external isolation transformer, and the normally closed contact is connected with the 220V connector in the primary coil of the external isolation transformer.

2. The circuit for automatically adapting to AC 110V and 220V power input according to claim 1, characterized in that: The voltage identification module includes the rectifier component, the input of the rectifier component is connected with the output of the soft start control module, and the rectified voltage is sent to the voltage division component.

3. The circuit for automatically adapting to AC 110V and 220V power input according to claim 2, characterized in that: The voltage division component is two groups of voltage division resistors, the two groups of voltage division resistors are connected in series, the middle node is used as the output, and the two ends are connected with the two stages of the output of the rectifier component respectively.

4. The circuit for automatically adapting to AC 110V and 220V power input according to claim 3, characterized in that: ​

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