CN205104901U - Anti thunderbolt surge protection circuit and have POS equipment of this circuit - Google Patents

Abstract

The utility model provides an anti-lightning surge protection circuit and a POS device with the circuit, including a thermistor, a piezoresistor, a first fuse and a second fuse, and the first fuse is connected in series with the piezoresistor to form a first protection The unit is connected in parallel to both ends of the power supply, and the second fuse is connected in series with the thermistor to form a second protection unit, which is connected in series to one end of the power supply. Strengthen the ability of the circuit to resist lightning surges, reduce the probability of equipment damage caused by lightning surge damage, and avoid equipment failure.

Description

An anti-lightning surge protection circuit and POS equipment with the circuit

technical field

The utility model relates to the technical field of electronic circuits, in particular to an anti-lightning surge protection circuit and a POS device with the circuit.

Background technique

When thunder strikes in summer, lightning generates high-voltage surge voltage at both ends of the power supply or between the zero and live wires of the power grid through space coupling, which is particularly obvious in plateau areas due to lightning strikes; one of the main reasons for electrical equipment damage due to lightning strikes is equipment The power part of the power supply is weak in anti-surge capability, resulting in damage.

Contents of the invention

The technical problem to be solved by the utility model is to provide an anti-lightning surge protection circuit and a POS device equipped with the circuit, so as to solve the problem of equipment damage caused by the circuit's weak anti-surge capability.

The utility model is achieved in the following way: an anti-lightning surge protection circuit, including a thermistor, a piezoresistor, a first fuse and a second fuse, the first fuse and the piezoresistor are connected in series to form a first protection unit connected in parallel to At both ends of the power supply, the second fuse is connected in series with the thermistor to form a second protection unit connected in series to one end of the power supply.

Further, the power supply is a DC power supply or an AC power supply.

Further, the power supply is commercial power, and the second protection unit is connected in series to the live wire end of the power supply.

Further, the first protection unit is connected in parallel with the power input end, one end of the second protection unit is connected with one end of the power input end and one end of the first protection unit, and the other end of the second protection unit is connected with one end of the power output end.

Further, the output end of the power supply is connected to a transformer circuit.

And the utility model also provides a kind of POS equipment with anti-lightning surge protection circuit, including power supply circuit, processing unit, display unit, input unit, communication unit and card swiping unit, described power supply circuit and processing unit, display unit, input The unit, the communication unit and the card swiping unit are connected, the processing unit is connected to the display unit, the input unit, the communication unit and the card swiping unit respectively, and the power circuit is also connected to the above-mentioned anti-lightning surge protection circuit.

The utility model has the following advantages: it strengthens the anti-lightning surge capability of the circuit, reduces the probability of equipment damage caused by lightning surge damage, and avoids equipment failure.

Description of drawings

Fig. 1 is the circuit diagram before the improvement of the utility model;

Fig. 2 is the circuit diagram of an embodiment of the utility model;

Fig. 3 is a circuit diagram of another embodiment of the present invention.

detailed description

In order to describe the technical content, structural features, achieved goals and effects of the present utility model in detail, the following will be described in detail in conjunction with the embodiments and accompanying drawings.

The protection circuit before improvement is shown in Figure 1. The AC power input terminal L (live wire) is connected to the fuse F, and the other terminal of F is connected to one terminal of the varistor MOV and one terminal of the thermistor NTC, and the output terminal is connected to the other terminal of the thermistor NTC. one end. The AC input terminal N (neutral line) is connected to the other end of the varistor; the other output terminal is connected to the AC input terminal N (neutral line).

When a high-voltage surge power supply is generated between the grid L and N, the voltage is added to both ends of the varistor MOV through the fuse F1. When the voltage at both ends of the MOV rises to the clamping voltage, the resistance of the MOV becomes smaller to limit the increase of the voltage at both ends of the MOV; the large current generated by the surge is consumed on the MOV after passing through F1 from the grid input terminal, and the voltage clamping effect of the MOV prevents the subsequent stage input high voltage.

The defect of this circuit is: the high-voltage and high-current energy generated by the surge needs to pass through the fuse F1 and then be absorbed by the varistor MOV. Because the fuse is required to be fused and disconnected in time when the power supply fails, the current specification of the fuse F1 cannot be large. When the surge energy is large, the current flowing through the fuse F1 is also large due to the clamping voltage at both ends of the MOV. At this time, the fuse with normal specifications will fuse and open the circuit due to the large current, resulting in power failure; the surge voltage before L/N of this solution Usually can only withstand 2.5KV.

As shown in Figure 2, the utility model provides an anti-lightning surge protection circuit, including a thermistor NTC, a varistor MOV, a first fuse F1 and a second fuse F2, and the first fuse is connected in series with the varistor to form The first protection unit is connected in parallel to both ends of the power supply, and the second fuse is connected in series with the thermistor to form the second protection unit, which is connected in series to one end of the power supply. Compared with the known solution, the surge energy absorbing circuit is changed and a fuse F1 is added. The AC input terminal L (live wire) is connected to the fuse F2 and the varistor MOV, and the other terminal of F2 is connected to the thermistor NTC; the AC output terminal is connected to the other terminal of the thermistor NTC. The AC input terminal N (neutral line) is connected to one end of the fuse F1, and the other end of the fuse F1 is connected to the other end of the varistor; the other output terminal is connected to the AC input terminal N (zero line).

When the lightning surge high voltage of the power grid is generated, the high voltage energy of the neutral wire N and the live wire L at the input end passes through the fuse F1 and then is absorbed by the varistor MOV. Because the fuse F2 of normal specifications can be blown and failed when the power supply fails, and the fuse F1 does not participate in the protection of the subsequent stage circuit. The fuse F1 can use a high-current fuse to withstand a large lightning surge voltage; according to this scheme, it can resist the L/N surge voltage above 6KV. Strengthen the circuit's ability to resist lightning surges, reduce the probability of equipment damage caused by lightning surge damage, and avoid equipment failure.

Among them, the utility model does not limit the specific connection relationship between the first protection unit and the second protection unit. After the protection unit is connected, it is connected to the first protection unit. In some embodiments, the contact point between the first protection unit and the circuit may be disposed between two components of the second protection unit. A preferred embodiment is that the first protection unit is connected in parallel with the power input end, one end of the second protection unit is connected with one end of the power input end and one end of the first protection unit, and the other end of the second protection unit is connected with one end of the power output end, that is It is the above-mentioned embodiment, and the effect of anti-lightning strike is better like this. The power supply of the present utility model can be a direct current power supply or an alternating current power supply. As in the above embodiment, when the power supply is commercial power, the second protection unit is connected in series to the live wire end of the power supply, which can protect the circuit more effectively.

As shown in FIG. 3 , the output end of the power supply is connected to a transformer circuit, and the transformer circuit is used to transform the voltage and provide it to the subsequent electric equipment.

And the utility model also provides a kind of POS equipment with anti-lightning surge protection circuit, including power supply circuit, processing unit, display unit, input unit, communication unit and card swiping unit, described power supply circuit and processing unit, display unit, input unit, the communication unit and the card swiping unit, the processing unit is connected to the display unit, the input unit, the communication unit and the card swiping unit respectively, and the power circuit is also connected to the anti-lightning surge protection circuit of any of the above-mentioned embodiments. Among them, the power supply circuit is used to provide power to each unit, the processing unit is used to process data, the display unit is used to display messages, the input unit is used to input passwords, the communication unit is used to communicate with the outside world, and the card swiping unit is used to obtain bank card information. The POS device with the above-mentioned anti-lightning surge protection circuit can better resist the lightning strike and prevent the POS device from being damaged by the lightning strike.

The above is only an embodiment of the utility model, and does not limit the scope of patent protection of the utility model. Any equivalent structure or equivalent process transformation made by using the utility model specification and accompanying drawings is directly or indirectly used in Other relevant technical fields are all included in the patent protection scope of the present utility model in the same way.

Claims (6)

1. an anti-lightning surging protection circuit; it is characterized in that: comprise thermistor, piezo-resistance, the first fuse and the second fuse; first fuse forms the first protected location after connecting with piezo-resistance and is parallel to both ends of power, and the second fuse forms one end that the second protected location is connected in series to power supply after connecting with thermistor.

2. a kind of anti-lightning surging protection circuit according to claim 1, is characterized in that: described power supply is DC power supply or AC power.

3. a kind of anti-lightning surging protection circuit according to claim 1, it is characterized in that: described power supply is civil power, the second protected location is connected in series to the live wire end of power supply.

4. a kind of anti-lightning surging protection circuit according to claim 1; it is characterized in that: the first protected location is in parallel with power input; one end of second protected location is connected with one end of one end of power input and the first protected location, and the other end of the second protected location is connected with one end of power output end.

5. a kind of anti-lightning surging protection circuit according to any one of claim 1 to 4, is characterized in that: the output of described power supply is connected with transforming circuit.

6. one kind has the POS terminal of anti-lightning surging protection circuit, it is characterized in that: comprise power circuit, processing unit, display unit, input unit, communication unit and unit of swiping the card, described power circuit is connected with processing unit, display unit, input unit, communication unit and unit of swiping the card, processing unit is connected respectively with display unit, input unit, communication unit and unit of swiping the card, and power circuit is also connected with a kind of anti-lightning surging protection circuit described in any one of claim 1 to 5.