CN210273479U - Power supply safety protection circuit of card reader - Google Patents
Power supply safety protection circuit of card reader Download PDFInfo
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- CN210273479U CN210273479U CN201921600319.2U CN201921600319U CN210273479U CN 210273479 U CN210273479 U CN 210273479U CN 201921600319 U CN201921600319 U CN 201921600319U CN 210273479 U CN210273479 U CN 210273479U
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Abstract
The utility model discloses a power safety protection circuit of ware of punching card. The overvoltage and undervoltage protection circuit comprises an overcurrent reverse connection protection circuit and an overvoltage and undervoltage protection circuit, wherein the overcurrent reverse connection protection circuit comprises a power interface, a Schottky diode and a common-mode inductor, and the overvoltage and undervoltage protection circuit comprises a high-side protection control chip and an MOS (metal oxide semiconductor) tube. The utility model carries out double division protection by the overcurrent reverse connection protection circuit and the overvoltage and undervoltage protection circuit, can absorb surge pulse caused by unstable external power supply through the overcurrent reverse connection protection circuit, can inhibit common mode electromagnetic interference of a card reader product, can achieve reverse interception aiming at overload and short circuit of a load, and achieves a reverse connection protection state; the overvoltage and undervoltage protection circuit can effectively realize undervoltage protection and overvoltage protection by calculating the resistance value of the resistor in the circuit.
Description
Technical Field
The utility model belongs to the technical field of the ware of punching the card technique and specifically relates to a power safety protection circuit of ware of punching the card.
Background
It is well known that card swipes are highly integrated electronic devices. The card reader reads the magnetic stripe information of the card holder on the bank card through the card reader, the cashier inputs the transaction amount, after the card holder inputs the password, the information is uploaded to the card sending bank system through the UnionPay center, the online transaction is completed, the information of success or failure is given, and the corresponding bill is printed.
The complex function and the use environment determine that the card reader needs a safer and more complete power supply circuit in the aspect of power supply, and the power supply circuit needs a safety protection circuit for protection in the actual application process so as to improve the safety and the reliability of power supply.
Disclosure of Invention
To the not enough of existence among the above-mentioned prior art, the utility model aims to provide a power safety protection circuit of ware of punching the card.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a power supply safety protection circuit of a card reader comprises an overcurrent reverse connection protection circuit and an overvoltage and undervoltage protection circuit, wherein the overcurrent reverse connection protection circuit comprises a power interface and a Schottky diode, the power interface is connected with the anode of the Schottky diode, the power interface and the Schottky diode are grounded through a first capacitor, a second capacitor and a first diode respectively, the cathode of the Schottky diode is connected with a common mode inductor, the other end of the common mode inductor is connected with a fuse and outputs power through the fuse, one end of the fuse is grounded through a fourth capacitor and a third capacitor, and the other end of the fuse is grounded through a fifth capacitor and a sixth capacitor;
overvoltage and undervoltage protection circuit includes high side protection control chip and MOS pipe, high side protection control chip is the LM5060 model, 4 end feet of high side protection control chip insert the power of overcurrent reversal connection protection circuit output through first resistance, 3 end feet of high side protection control chip pass through second resistance and first resistance connection and through third resistance ground connection, 1 end foot of high side protection control chip passes through the fourth resistance and is connected with the drain electrode of MOS pipe, the drain electrode of MOS pipe inserts the power of overcurrent reversal connection protection circuit output, 9 end feet of high side protection control chip pass through the fifth resistance and are connected with the source electrode of MOS pipe, 10 end feet of high side protection control chip are connected with the grid of MOS pipe, 7 end feet of high side protection control chip pass through the ninth electric capacity ground connection, the source electrode output power of MOS pipe passes through seventh electric capacity, And the eighth capacitor and the second diode are grounded.
Preferably, the first diode is a TVS tube.
Preferably, the fuse is a self-restoring fuse.
Preferably, the MOS transistor is an NMOS transistor, and the second diode is a TVS transistor.
Due to the adoption of the scheme, the utility model carries out double division protection by the overcurrent reverse connection protection circuit and the overvoltage and undervoltage protection circuit, can absorb surge pulse caused by unstable external power supply through the overcurrent reverse connection protection circuit, can inhibit common-mode electromagnetic interference of a card reader product, can achieve reverse interception aiming at overload and short circuit of a load, and achieves a reverse connection protection state; the overvoltage and undervoltage protection circuit can effectively realize undervoltage protection and overvoltage protection by calculating the resistance value of the resistor in the circuit.
Drawings
Fig. 1 is a schematic diagram of the structural principle of the embodiment of the present invention.
Fig. 2 is a schematic structural diagram of an overcurrent reverse connection protection circuit according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of an overvoltage/undervoltage protection circuit according to an embodiment of the present invention.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
As shown in fig. 1 to fig. 3, the power supply safety protection circuit of a card reader provided in this embodiment includes an overcurrent reverse connection protection circuit and an overvoltage/undervoltage protection circuit, the overcurrent reverse connection protection circuit includes a power interface P1 and a schottky diode D1, the power interface P1 is connected to the positive electrode of the schottky diode D1, the power interface P1 and the schottky diode D1 are grounded through a first capacitor C1, a second capacitor C2, and a first diode D2, respectively, the negative electrode of the schottky diode D1 is connected to a common mode inductor L1, the other end of the common mode inductor L1 is connected to a fuse F1 and outputs power through a fuse F1, one end of the fuse F1 is grounded through a fourth capacitor C4 and a third capacitor C3, and the other end is grounded through a fifth capacitor C5 and a sixth capacitor C6;
the overvoltage and undervoltage protection circuit comprises a high-side protection control chip U1 and a MOS tube Q1, the high-side protection control chip U1 is of an LM5060 model, a 4 terminal pin of the high-side protection control chip U1 is connected with a power supply output by an overcurrent reverse-connection protection circuit through a first resistor R1, a 3 terminal pin of the high-side protection control chip U1 is connected with a first resistor R1 through a second resistor R2 and is grounded through a third resistor R3, a 1 terminal pin of the high-side protection control chip U1 is connected with a drain electrode of the MOS tube Q1 through a fourth resistor R4, a drain electrode of the MOS tube Q1 is connected with the power supply output by the overcurrent reverse-connection protection circuit, a 9 terminal pin of the high-side protection control chip U1 is connected with a source electrode of the MOS tube Q1 through a fifth resistor R5, a 10 terminal pin of the high-side protection control chip U1 is connected with a gate of the MOS tube Q1, a terminal pin of the high-side protection control chip U1 is grounded through a ninth capacitor C375, and a source electrode of the MOS tube Q5857323 is, The eighth capacitor C8 and the second diode D3 are grounded.
Further, the first diode D2 is a TVS tube.
Further, the fuse F1 is a self-recovery fuse.
Furthermore, the MOS transistor is an NMOS transistor, and the second diode is a TVS transistor.
The power interface of the embodiment is connected to a power supply (DC 12V), a first capacitor C1 and a second capacitor C2 of the power interface are filter capacitors, a schottky diode D1 is an MBRD620, a first diode D2 is a transient voltage suppression diode (TVS) which is a TVS tube, surge pulses caused by instability of an external power supply can be absorbed, a common-mode inductor L1 can suppress common-mode electromagnetic interference of a product, a fuse F1 is a self-recovery fuse, and a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6 act on filtering. If the rear-stage load is overloaded or short-circuited, the current is rapidly increased, the self-recovery fuse F1 is blown out, and the overcurrent protection state is entered. If the polarity of the power supply is reversely connected (the positive pole is connected to pins 3 and 4 of the power interface P1, and the negative pole is connected to pin 5), the power-on moment D1 is reversely cut off, the circuit has no output, and the circuit is in a reverse connection protection state.
The overvoltage and undervoltage protection circuit is shown in fig. 3, and is composed of a high-side protection control chip U1 and peripheral components thereof. Two voltage comparators are arranged in a high-side protection control chip U1 in the circuit, a 3-terminal pin (OVP) of the high-side protection control chip U1 is an input end of an internal overvoltage protection comparator, the input voltage is compared with 2.0V voltage, when the input voltage is more than 2.0V, the comparator outputs high level, and a power supply is turned off through an internal logic circuit, so that overvoltage protection is started; the 4 terminal pin (UVLO) is the input end of the internal undervoltage protection comparator, compares the voltage input therein with 1.6V, and when the voltage is lower than 1.6V, the comparator outputs high level, thereby starting undervoltage protection; the 7-end pin is connected with a ninth capacitor C9 which is also an input end of an external timing capacitor, so that delay time can be set, and the protection circuit is prevented from being started by mistake. The MOS transistor Q1 is an NMOS transistor and is used as a switch of a power supply; the first resistor R1, the second resistor R2 and the third resistor R3 form an input voltage sampling resistor; the fourth resistor R4 and the fifth resistor R5 are used for detecting VDS voltage faults of the MOS transistor Q1; the second diode D3 is a TVS tube and is used for absorbing surge pulse of an external power supply; the ninth capacitor C9 is a timing capacitor that sets the VDS fault detection delay time. In the circuit shown in fig. 3, the sampling resistor includes a first resistor R1, a second resistor R2, and a third resistor R3, which are used for dividing voltage and then sending the voltage to a 4 terminal pin and a 2 terminal pin of a high-side protection control chip U1, and according to the calculation of resistance values of the resistors, when the input voltage is less than 9.45V, the under-voltage protection is started; when the input voltage is greater than 17V, overvoltage protection is enabled.
The above is only the preferred embodiment of the present invention, and not the scope of the present invention, all the equivalent structures or equivalent flow changes made by the contents of the specification and the drawings or the direct or indirect application in other related technical fields are included in the patent protection scope of the present invention.
Claims (4)
1. The utility model provides a power safety protection circuit of ware of punching card which characterized in that: the overvoltage and undervoltage protection circuit comprises an overcurrent reverse connection protection circuit and an overvoltage and undervoltage protection circuit, wherein the overcurrent reverse connection protection circuit comprises a power interface and a Schottky diode, the power interface is connected with the anode of the Schottky diode, the power interface and the Schottky diode are grounded through a first capacitor, a second capacitor and the first diode respectively, the cathode of the Schottky diode is connected with a common mode inductor, the other end of the common mode inductor is connected with a fuse and outputs power through the fuse, one end of the fuse is grounded through a fourth capacitor and a third capacitor, and the other end of the fuse is grounded through a fifth capacitor and a sixth capacitor;
overvoltage and undervoltage protection circuit includes high side protection control chip and MOS pipe, high side protection control chip is the LM5060 model, 4 end feet of high side protection control chip insert the power of overcurrent reversal connection protection circuit output through first resistance, 3 end feet of high side protection control chip pass through second resistance and first resistance connection and through third resistance ground connection, 1 end foot of high side protection control chip passes through the fourth resistance and is connected with the drain electrode of MOS pipe, the drain electrode of MOS pipe inserts the power of overcurrent reversal connection protection circuit output, 9 end feet of high side protection control chip pass through the fifth resistance and are connected with the source electrode of MOS pipe, 10 end feet of high side protection control chip are connected with the grid of MOS pipe, 7 end feet of high side protection control chip pass through the ninth electric capacity ground connection, the source electrode output power of MOS pipe passes through seventh electric capacity, And the eighth capacitor and the second diode are grounded.
2. The power supply safety protection circuit of the card reader as claimed in claim 1, wherein: the first diode is a TVS tube.
3. The power supply safety protection circuit of the card reader as claimed in claim 1, wherein: the fuse is a self-restoring fuse.
4. The power supply safety protection circuit of the card reader as claimed in claim 1, wherein: the MOS tube is an NMOS tube, and the second diode is a TVS tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921600319.2U CN210273479U (en) | 2019-09-25 | 2019-09-25 | Power supply safety protection circuit of card reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921600319.2U CN210273479U (en) | 2019-09-25 | 2019-09-25 | Power supply safety protection circuit of card reader |
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| Publication Number | Publication Date |
|---|---|
| CN210273479U true CN210273479U (en) | 2020-04-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921600319.2U Active CN210273479U (en) | 2019-09-25 | 2019-09-25 | Power supply safety protection circuit of card reader |
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| CN (1) | CN210273479U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111525516A (en) * | 2020-05-21 | 2020-08-11 | 上海华铭智能终端设备股份有限公司 | Power supply device and vehicle-mounted POS machine |
-
2019
- 2019-09-25 CN CN201921600319.2U patent/CN210273479U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111525516A (en) * | 2020-05-21 | 2020-08-11 | 上海华铭智能终端设备股份有限公司 | Power supply device and vehicle-mounted POS machine |
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