CN213151651U - Reverse connection prevention protection device and vehicle-mounted power supply - Google Patents

Abstract

The embodiment of the utility model discloses prevent reverse-connection protection device and vehicle mounted power. Wherein, should prevent reverse-connection protection device includes: the first input end and the second input end of the first-stage reverse connection prevention protection circuit are respectively and electrically connected with the positive input end and the negative input end of the reverse connection prevention protection device; the first output end and the second output end of the previous stage of reverse connection prevention protection circuit are respectively and electrically connected with the first input end and the second input end of the next stage of reverse connection prevention protection circuit; and the second output end of the first output end of the last stage of reverse connection prevention protection circuit is electrically connected with the positive output end and the negative output end of the reverse connection prevention protection device respectively. The embodiment of the utility model provides a condition emergence that the system was destroyed when technical scheme can avoid input voltage polarity reversal to connect.

Description

Reverse connection prevention protection device and vehicle-mounted power supply

Technical Field

The utility model relates to the technical field of circuits, especially, relate to a prevent reverse connection protection device and vehicle mounted power.

Background

The electronic system has many independent power modules, and the input end of the power module mainly distinguishes the polarity by a mechanical or pattern identification mode, thereby providing an instructive scheme. However, this cannot prevent the input terminal from being reversely connected, and once the input terminal is reversely connected, the input voltage port will be damaged, the power module will be burned out, and even the power supply or the battery will be out of service, which further causes economic loss.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a prevent reverse-connection protection device and vehicle mounted power can prevent that input voltage polarity from reversing the time and destroying the system, prevents reverse-connection protection circuit through setting up more than the two-stage, can further improve the reliability and the security of system, even the preceding stage prevents that reverse-connection circuit became invalid, and the back stage is prevented reverse-connection circuit and can be played.

In a first aspect, an embodiment of the present invention provides an anti-reverse-connection protection device, including:

the first input end of the first-stage reverse connection prevention protection circuit is electrically connected with the positive input end of the reverse connection prevention protection device; the second input end of the first-stage reverse connection prevention protection circuit is electrically connected with the negative input end of the reverse connection prevention protection device; the first output end of the previous stage reverse connection prevention protection circuit is electrically connected with the first input end of the next stage reverse connection prevention protection circuit; the second output end of the previous stage reverse connection prevention protection circuit is electrically connected with the second input end of the next stage reverse connection prevention protection circuit; the first output end of the last stage of reverse connection prevention protection circuit is electrically connected with the positive output end of the reverse connection prevention protection device; and the second output end of the last stage of reverse connection prevention protection circuit is electrically connected with the negative output end of the reverse connection prevention protection device.

Further, the at least two cascaded reverse-connection prevention protection circuits comprise: at least one first reverse-connection prevention protection circuit,

the first reverse connection prevention protection circuit comprises a PMOS (P-channel metal oxide semiconductor) tube, a first diode, a first voltage stabilizing diode, a first resistor and a second resistor, wherein a drain electrode of the PMOS tube and an anode of the first diode are electrically connected with a first input end of the first reverse connection prevention protection circuit; the source electrode of the PMOS tube, the cathode of the first diode, the cathode of the first voltage stabilizing diode and the first end of the first resistor are electrically connected with the first output end of the first reverse connection prevention protection circuit; the grid electrode of the PMOS tube, the anode of the first voltage stabilizing diode and the second end of the first resistor are electrically connected with the first end of the second resistor; the second end of the second resistor and the second input end of the first reverse-connection prevention protection circuit are electrically connected with the second output end of the first reverse-connection prevention protection circuit.

Further, the at least two cascaded reverse-connection prevention protection circuits comprise: at least one second reverse-connection prevention protection circuit,

the second reverse connection prevention protection circuit comprises an NMOS (N-channel metal oxide semiconductor) tube, a second diode, a second voltage stabilizing diode, a third resistor and a fourth resistor, wherein the drain electrode of the NMOS tube and the cathode of the second diode are electrically connected with the second input end of the second reverse connection prevention protection circuit; the source electrode of the NMOS tube, the anode of the second diode, the anode of the second voltage stabilizing diode and the first end of the third resistor are electrically connected with the second output end of the second reverse connection prevention protection circuit; the grid electrode of the NMOS tube, the cathode of the second voltage stabilizing diode and the second end of the third resistor are electrically connected with the first end of the fourth resistor; the second end of the fourth resistor and the first input end of the second reverse-connection prevention protection circuit are electrically connected with the first output end of the second reverse-connection prevention protection circuit.

Further, the at least two cascaded reverse-connection prevention protection circuits comprise: at least one third protection circuit is connected in reverse,

the third protection circuit comprises a third diode, a fourth diode, a direct current-to-direct current voltage reduction circuit, a first relay and a fifth diode, wherein the cathode of the third diode and the first end of the normally closed contact switch of the first relay are electrically connected with the first input end of the third protection circuit; the second end of the normally closed contact switch of the first relay is electrically connected with the first output end of the third protection reverse connection protection circuit; the anode of the third diode is electrically connected with the negative input end of the direct current-to-direct current voltage reduction circuit; the anode of the fourth diode and the second input end of the third anti-reverse-connection protection circuit are electrically connected with the second output end of the third anti-reverse-connection protection circuit; the cathode of the fourth diode is electrically connected with the anode input end of the direct current-to-direct current voltage reduction circuit; the first end of the coil of the first relay and the cathode of the fifth diode are electrically connected with the anode output end of the direct current-to-direct current voltage reduction circuit; and the second end of the coil of the first relay and the anode of the fifth diode are electrically connected with the negative output end of the direct current-to-direct current voltage reduction circuit.

Furthermore, the reverse connection prevention protection device also comprises a first reverse connection alarm circuit, wherein the first end and the second end of the first reverse connection alarm circuit are respectively and electrically connected with the positive input end and the negative input end of the reverse connection prevention protection device, and the first reverse connection alarm circuit is used for alarming when in reverse connection.

Further, the first reverse connection alarm circuit comprises a first light emitting diode, a sixth diode and a fifth resistor, wherein the first light emitting diode, the sixth diode and the fifth resistor are connected in series, and two ends of the first reverse connection alarm circuit after the series connection are respectively and electrically connected with the first end and the second end of the first reverse connection alarm circuit.

Furthermore, the reverse connection prevention protection device also comprises a second reverse connection alarm circuit, wherein the first end and the second end of the second reverse connection alarm circuit are respectively and electrically connected with the first output end and the second output end of the first-stage reverse connection prevention protection circuit, and the second reverse connection alarm circuit is used for alarming when the first-stage reverse connection prevention protection circuit fails and is reversely connected.

Further, the second reverse connection alarm circuit comprises a seventh diode, an eighth diode, a low dropout regulator and a buzzer, wherein the cathode of the seventh diode is electrically connected with the first end of the second reverse connection alarm circuit; the anode of the seventh diode is electrically connected with the negative input end of the low dropout regulator; the anode of the eighth diode is electrically connected with the second end of the second reverse connection alarm circuit; the cathode of the eighth diode is electrically connected with the positive input end of the low dropout regulator; the first end and the second end of the buzzer are respectively and electrically connected with the positive output end and the negative output end of the low dropout linear regulator.

In a second aspect, the embodiment of the present invention further provides an onboard power supply, including: an energy storage module, a DC-to-AC conversion circuit, a second relay and an anti-reverse connection protection device provided by any embodiment of the utility model,

the energy storage module is electrically connected with a positive input end and a negative input end of the reverse connection prevention protection device, and a positive output end of the reverse connection prevention protection device is electrically connected with a first input end of the direct current-to-alternating current conversion circuit; the negative output end of the reverse connection prevention protection device is electrically connected with the second input end of the direct current-to-alternating current conversion circuit; the output end of the direct current-to-alternating current conversion circuit is electrically connected with the output end of the vehicle-mounted power supply through a normally closed contact switch of the second relay; and the first end and the second end of the coil of the second relay are respectively electrically connected with the first alternating current power supply end and the second alternating current power supply end, and the first alternating current power supply end and the second alternating current power supply end are electrically connected with the output end of the vehicle-mounted power supply through the normally open contact switch of the second relay.

Further, the vehicle-mounted power supply further includes: the wireless energy transmitting device is used for transmitting energy to a mobile terminal provided with a wireless energy receiving device so as to wirelessly charge the mobile terminal;

the mobile terminal comprises at least one of the following: mobile phones, notebook computers, tablet computers and portable digital X-ray photography equipment.

The utility model discloses prevent reverse connection protection device includes among the technical scheme: the first input end of the first-stage reverse connection prevention protection circuit is electrically connected with the positive input end of the reverse connection prevention protection device; the second input end of the first-stage reverse connection prevention protection circuit is electrically connected with the negative input end of the reverse connection prevention protection device; the first output end of the previous stage reverse connection prevention protection circuit is electrically connected with the first input end of the next stage reverse connection prevention protection circuit; the second output end of the previous stage reverse connection prevention protection circuit is electrically connected with the second input end of the next stage reverse connection prevention protection circuit; the first output end of the last stage of reverse connection prevention protection circuit is electrically connected with the positive output end of the reverse connection prevention protection device; and the second output end of the last stage of reverse connection prevention protection circuit is electrically connected with the negative output end of the reverse connection prevention protection device. The rear-stage reverse connection prevention protection circuit is used for enabling the first input end and the second input end of the reverse connection prevention protection circuit to be in a disconnection state when the preceding-stage reverse connection prevention protection circuit fails and reverse connection occurs, or enabling the first output end and the second output end of the reverse connection prevention protection circuit to be in a disconnection state, and further enabling the positive input end and the positive output end of the reverse connection prevention protection device to be in a disconnection state, or enabling the negative input end and the negative output end of the reverse connection prevention protection device to be in a disconnection state, so that the situation that a system is damaged when the polarity of input voltage is reverse connected is avoided.

Drawings

Fig. 1 is a schematic structural diagram of an anti-reverse connection protection device provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another reverse connection prevention protection device provided by the embodiment of the present invention;

fig. 3 is a schematic structural diagram of another reverse connection prevention protection device provided by the embodiment of the present invention;

fig. 4 is a schematic structural diagram of a vehicle-mounted power supply according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of another vehicle-mounted power supply according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a voltage boosting circuit according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of an inverter according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

The embodiment of the utility model provides a prevent reverse connection protection device. Fig. 1 is a schematic structural diagram of an anti-reverse connection protection device provided by an embodiment of the present invention. The reverse connection prevention protection device 1 includes: at least two cascaded anti-reverse-connect protection circuits 10.

The first input end Vi1 of the first-stage reverse connection prevention protection circuit 10-1 is electrically connected with the positive input end BAT + of the reverse connection prevention protection device 1; the second input end Vi2 of the first-stage reverse connection prevention protection circuit 10-1 is electrically connected with the negative input end BAT-of the reverse connection prevention protection device 1; the first output end Vo1 of the previous stage reverse connection prevention protection circuit 10-k is electrically connected with the first input end Vi1 of the next stage reverse connection prevention protection circuit 10- (k + 1); the second output end Vo2 of the previous stage reverse connection prevention protection circuit 10-k is electrically connected with the second input end Vi2 of the next stage reverse connection prevention protection circuit 10- (k + 1); the first output Vo1 of the last stage reverse connection prevention protection circuit 10-N is electrically connected with the positive output terminal BOUT + of the reverse connection prevention protection device 1; the second output Vo2 of the last stage reverse connection prevention protection circuit 10-N is electrically connected with the negative output terminal BOUT-of the reverse connection prevention protection device 1.

Wherein k is an integer greater than or equal to 1 and less than N. N is the number of the reverse connection preventing protection circuits 10, and is an integer greater than or equal to 2. Fig. 1 exemplarily shows the case that the number of the reverse connection prevention protection circuits 10 is 4, which are reverse connection prevention protection circuits 10-1, 10-2, 10-3 and 10-4, respectively. The number of the reverse connection preventing protection circuits can be set according to the requirement, and the embodiment of the utility model provides a do not limit this. The reverse-connection prevention protection circuit 10 may include a diode, a MOS transistor, a relay, and the like.

The reverse connection prevention protection device can be used for enabling the positive input terminal BAT + and the positive output terminal BOUT + to be in a disconnection state and/or enabling the negative input terminal BAT-and the negative output terminal BOUT-to be in a disconnection state when in reverse connection; when the input voltage is not reversely connected, the positive input terminal BAT + and the positive output terminal BOUT + are in a conducting state, and the negative input terminal BAT-and the negative output terminal BOUT-are in a conducting state. The reverse connection prevention protection circuit 10 is used for enabling the first input end Vi1 and the second input end Vi2 of the first-stage reverse connection prevention protection circuit to be in a disconnection state when the voltage of the first input end Vi1 is lower than the voltage of the second input end Vi2, or enabling the first output end Vo1 and the second output end Vo2 of the first-stage reverse connection prevention protection circuit to be in a disconnection state; when the voltage of the first input terminal Vi1 is higher than the voltage of the second input terminal Vi2, the first input terminal Vi1 and the second input terminal Vi2 of the first stage reverse connection prevention protection circuit are in a conducting state, and the first output terminal Vo1 and the second output terminal Vo2 of the first stage reverse connection prevention protection circuit are in a conducting state.

The first-stage reverse connection prevention protection circuit can be used for enabling the first input end Vi1 of the first-stage reverse connection prevention protection circuit 10-1 to be lower than the voltage of the second input end Vi2 when the first-stage reverse connection prevention protection circuit is effective and reverse connection occurs, so that the first input end Vi1 and the second input end Vi2 of the first-stage reverse connection prevention protection circuit are in a disconnected state, or the first output end Vo1 and the second output end Vo2 of the first-stage reverse connection prevention protection circuit are in a disconnected state, so that the positive input end BAT + and the positive output end BOUT + of the reverse connection prevention protection device are in a disconnected state, or the negative input end BAT-and the negative output end BOUT-of the reverse connection prevention protection device are in a disconnected state; when the first input end Vi1 of the first-stage reverse connection prevention protection circuit 10-1 is not reversely connected, the voltage of the first input end Vi1 is higher than the voltage of the second input end Vi2, so that the first input end Vi1 and the second input end Vi2 of the first-stage reverse connection prevention protection circuit are in a conducting state, the first output end Vo1 and the second output end Vo2 of the first-stage reverse connection prevention protection circuit are in a conducting state, the positive input end BAT + and the positive output end BOUT + are in a conducting state, and the negative input end BAT-and the negative output end BOUT-are in a conducting state.

Any one of the back-stage reverse-connection prevention protection circuits 10 can be used for enabling a first input terminal Vi1 and a second input terminal Vi2 of the reverse-connection prevention protection circuit to be in a disconnection state when the preceding stage reverse-connection prevention protection circuit fails and reverse connection occurs, or enabling a first output terminal Vo1 and a second output terminal Vo2 of the reverse-connection prevention protection circuit to be in a disconnection state, and further enabling a positive input terminal BAT + and a positive output terminal BOUT + of the reverse-connection prevention protection device to be in a disconnection state, or enabling a negative input terminal BAT-and a negative output terminal BOUT-of the reverse-connection prevention protection device to be in a disconnection state. The rear stage reverse connection prevention protection circuit 10 may include a reverse connection prevention protection circuit behind the first stage reverse connection prevention protection circuit, that is, a second stage reverse connection prevention protection circuit and a reverse connection prevention protection circuit behind the second stage reverse connection prevention protection circuit.

It should be noted that a battery and the like can be connected between the positive input terminal BAT + and the negative input terminal BAT-; and a load and the like can be connected between the positive output end BOUT + and the negative output end BOUT-.

If the positive input terminal BAT + and the negative input terminal BAT-are correctly connected, illustratively, the positive electrode of the battery is connected with the positive input terminal BAT + of the reverse connection prevention protection device 1; the negative pole of the battery is connected with the negative pole input terminal BAT-of the reverse-connection prevention protection device 1, and all the reverse-connection prevention protection circuits are not damaged, so that each reverse-connection prevention protection circuit 10 does not work, the positive pole input terminal BAT + and the positive pole output terminal BOUT + are in a conduction state, the negative pole input terminal BAT-and the negative pole output terminal BOUT-are in a conduction state, and therefore the accessed high potential of the positive pole input terminal BAT + is transmitted to the positive pole output terminal BOUT +, and the accessed low potential of the negative pole input terminal BAT-is transmitted to the negative pole output terminal BOUT-.

If the positive input terminal BAT + and the negative input terminal BAT-are connected incorrectly to cause reverse connection, illustratively, the negative electrode of the battery is connected with the positive input terminal BAT + of the reverse connection prevention protection device 1; the positive pole of the battery is connected with the negative pole input terminal BAT-of the reverse connection prevention protection device 1, and all reverse connection prevention protection circuits are not damaged, at least the first-stage reverse connection prevention protection circuit 10-1 acts to enable the positive pole input terminal BAT + and the positive pole output terminal BOUT + to be in a disconnected state, and/or enable the negative pole input terminal BAT-and the negative pole output terminal BOUT-to be in a disconnected state, so that the situation that the system is damaged when the polarity of input voltage is reversely connected is avoided. If reverse connection occurs and the preceding stage reverse connection prevention protection circuit fails, the subsequent stage reverse connection prevention protection circuit acts, illustratively, if the first stage reverse connection prevention protection circuit 10-1 fails, at least the second stage reverse connection prevention protection circuit 10-2 acts to enable the positive input terminal BAT + and the positive output terminal BOUT + to be in a disconnected state, or enable the negative input terminal BAT-and the negative output terminal BOUT-to be in a disconnected state, so that the situation that the system is damaged when the polarity of the input voltage is reversely connected is avoided.

In the technical scheme of the embodiment, the reverse connection prevention protection device comprises: the first input end of the first-stage reverse connection prevention protection circuit is electrically connected with the positive input end of the reverse connection prevention protection device; the second input end of the first-stage reverse connection prevention protection circuit is electrically connected with the negative input end of the reverse connection prevention protection device; the first output end of the previous stage reverse connection prevention protection circuit is electrically connected with the first input end of the next stage reverse connection prevention protection circuit; the second output end of the previous stage reverse connection prevention protection circuit is electrically connected with the second input end of the next stage reverse connection prevention protection circuit; the first output end of the last stage of reverse connection prevention protection circuit is electrically connected with the positive output end of the reverse connection prevention protection device; and the second output end of the last stage of reverse connection prevention protection circuit is electrically connected with the negative output end of the reverse connection prevention protection device. The rear-stage reverse connection prevention protection circuit is used for enabling the first input end and the second input end of the reverse connection prevention protection circuit to be in a disconnection state when the preceding-stage reverse connection prevention protection circuit fails and reverse connection occurs, or enabling the first output end and the second output end of the reverse connection prevention protection circuit to be in a disconnection state, and further enabling the positive input end and the positive output end of the reverse connection prevention protection device to be in a disconnection state, or enabling the negative input end and the negative output end of the reverse connection prevention protection device to be in a disconnection state, so that the situation that a system is damaged when the polarity of input voltage is reverse connected is avoided.

Optionally, on the basis of the foregoing embodiment, fig. 2 is a schematic structural diagram of another reverse connection prevention protection device provided in an embodiment of the present invention, where at least two cascaded reverse connection prevention protection circuits include: at least one first reverse-connection prevention protection circuit 11.

The first reverse connection prevention protection circuit comprises a PMOS (P-channel metal oxide semiconductor) tube Q1, a first diode D1, a first voltage stabilizing diode Z1, a first resistor R1 and a second resistor R2, wherein the drain electrode of the PMOS tube Q1 and the anode electrode of the first diode D1 are electrically connected with a first input end Vi1 of the first reverse connection prevention protection circuit 11; the source of the PMOS transistor Q1, the cathode of the first diode D1, the cathode of the first zener diode Z1, and the first end of the first resistor R1 are all electrically connected to the first output Vo1 of the first reverse-connection-prevention protection circuit 11; the grid electrode of the PMOS pipe Q1, the anode electrode of the first voltage-stabilizing diode Z1 and the second end of the first resistor R1 are electrically connected with the first end of the second resistor R2; the second terminal of the second resistor R2 and the second input terminal Vi2 of the first reverse-connection prevention protection circuit 11 are electrically connected to the second output terminal Vo2 of the first reverse-connection prevention protection circuit 11.

Any stage of reverse connection prevention protection circuit can be the first reverse connection prevention protection circuit 11, and the number and the position of the first reverse connection prevention protection circuit 11 can be set according to requirements. The first stage reverse-connection prevention protection circuit 10-1 may be a first reverse-connection prevention protection circuit 11. The first diode D1 may be the body diode of PMOS transistor Q1.

Illustratively, the first stage reverse-connection prevention protection circuit 10-1 may be the first reverse-connection prevention protection circuit 11 and is not disabled (i.e., not damaged). If no reverse connection occurs, the first diode D1 is turned on, and the voltage between the gate and the source of the PMOS transistor Q1 is low, so the PMOS transistor Q1 is turned on, and since the on-state impedance of the PMOS transistor Q1 is smaller than the on-state impedance of the first diode D1, the power consumption can be reduced. If the reverse connection occurs, the first diode D1 is turned off, and the absolute value of the voltage between the gate and the source of the PMOS transistor Q1 is smaller than the absolute value of the turn-on threshold voltage, so that the PMOS transistor Q1 is turned off, and the positive input terminal BAT + and the positive output terminal BOUT + are in a disconnected state, thereby avoiding the occurrence of the condition that the system is damaged when the polarity of the input voltage is reversed.

Optionally, on the basis of the foregoing embodiment, with continuing reference to fig. 2, the at least two cascaded reverse connection prevention protection circuits include: at least one second reverse-connection protection circuit 12.

The second reverse-connection prevention protection circuit 12 comprises an NMOS transistor Q2, a second diode D2, a second zener diode Z2, a third resistor R3 and a fourth resistor R4, wherein a drain of the NMOS transistor Q2 and a cathode of the second diode D2 are electrically connected with a second input terminal Vi2 of the second reverse-connection prevention protection circuit 12; the source of the NMOS transistor Q2, the anode of the second diode D2, the anode of the second zener diode Z2, and the first end of the third resistor R3 are all electrically connected to the second output Vo2 of the second anti-reverse protection circuit 12; the grid electrode of the NMOS tube Q2, the cathode electrode of the second voltage stabilizing diode Z2 and the second end of the third resistor R3 are electrically connected with the first end of the fourth resistor R4; the second end of the fourth resistor R4 and the first input Vi1 of the second anti-reverse-connection protection circuit 12 are electrically connected to the first output Vo1 of the second anti-reverse-connection protection circuit 12.

Any stage of the reverse connection prevention protection circuit can be the second reverse connection prevention protection circuit 12, and the number and the position of the second reverse connection prevention protection circuit 12 can be set according to requirements. The second stage reverse-connection protection circuit 10-2 may be a second reverse-connection protection circuit 12. The second diode D2 may be a body diode of the NMOS transistor Q2.

Illustratively, the first stage reverse-connection prevention protection circuit 10-1 can be the first reverse-connection prevention protection circuit 11 and is not disabled. The second stage reverse connection prevention protection circuit 10-2 may be the second reverse connection prevention protection circuit 12 and is not disabled. If no reverse connection occurs, the first diode D1 is turned on, the PMOS transistor Q1 is turned on, the second diode D2 is turned on, and the voltage between the gate and the source of the NMOS transistor Q2 is high, so the NMOS transistor Q2 is turned on, and since the on-state impedance of the NMOS transistor Q2 is smaller than the on-state impedance of the second diode D2, power consumption can be reduced. If the reverse connection occurs, the first diode D1 is turned off, the PMOS tube Q1 is turned off, the anode input terminal BAT + and the anode output terminal BOUT + are in a disconnected state, the second diode D2 is turned off, the NMOS tube Q2 is turned off, and the cathode input terminal BAT-and the cathode output terminal BOUT-are in a disconnected state, so that the situation that the system is damaged when the polarity of the input voltage is reversely connected is avoided.

Illustratively, the first stage reverse-connection prevention protection circuit 10-1 may be the first reverse-connection prevention protection circuit 11 and fails, illustratively, the first diode D1 or the PMOS transistor Q1 breaks down. It should be noted that, if the reverse connection prevention protection circuit fails, whether the reverse connection is performed or not, the first input Vi1 and the first output Vo1 of the stage reverse connection prevention protection circuit 10 are in a conducting state, and the second input Vi2 and the second output Vo2 of the stage reverse connection prevention protection circuit 10 are in a conducting state. The second stage reverse connection prevention protection circuit 10-2 may be the second reverse connection prevention protection circuit 12 and is not disabled. If reverse connection occurs, the first-stage reverse connection prevention protection circuit 10-1 does not work, the second diode D2 is turned off, and the NMOS tube Q2 is turned off, so that the negative input terminal BAT-and the negative output terminal BOUT-are in a disconnected state, and the situation that the system is damaged when the polarity of the input voltage is reversely connected is avoided.

Optionally, on the basis of the foregoing embodiment, with continuing reference to fig. 2, the at least two cascaded reverse connection prevention protection circuits include: at least one third protection circuit 13 is connected in reverse.

The third protection circuit 13 comprises a third diode D3, a fourth diode D4, a dc-to-dc voltage reduction circuit 131, a first relay 132 and a fifth diode D5, wherein the cathode of the third diode D3 and the first end of the normally closed contact switch of the first relay 132 are electrically connected with the first input end Vi1 of the third protection circuit 13; the second end of the normally closed contact switch of the first relay 132 is electrically connected with the first output end Vo1 of the third protection reverse connection protection circuit 13; the anode of the third diode D3 is electrically connected with the negative input Vi-of the dc-to-dc voltage reduction circuit 131; the anode of the fourth diode D4 and the second input Vi2 of the third anti-reverse-connection protection circuit 13 are electrically connected to the second output Vo2 of the third anti-reverse-connection protection circuit 13; the cathode of the fourth diode D4 is electrically connected to the positive input Vi + of the dc-to-dc voltage reduction circuit 131; a first end of the coil of the first relay 132 and a cathode of the fifth diode D5 are electrically connected to the positive output Vo + of the dc-to-dc voltage step-down circuit 131; the second end of the coil of the first relay 132 and the anode of the fifth diode D5 are electrically connected to the negative output Vo-of the dc-to-dc voltage step-down circuit 131.

Any stage of reverse connection prevention protection circuit can be a third reverse connection prevention protection circuit 13, and the number and the positions of the third reverse connection prevention protection circuit 13 can be set according to needs. The third stage reverse connection prevention protection circuit 10-3 may be a third reverse connection prevention protection circuit 13. The dc-dc voltage reduction circuit 131 may include a buck circuit and the like.

Illustratively, the first stage reverse-connection prevention protection circuit 10-1 can be the first reverse-connection prevention protection circuit 11 and is not disabled. The second stage reverse connection prevention protection circuit 10-2 may be the second reverse connection prevention protection circuit 12 and is not disabled. The third stage reverse connection prevention protection circuit 10-3 can be a third reverse connection prevention protection circuit 13 and is not invalid. If the reverse connection does not occur, the first diode D1 is turned on, the PMOS transistor Q1 is turned on, the second diode D2 is turned on, the NMOS transistor Q2 is turned on, the third diode D3 is turned off, the fourth diode D4 is turned off, and the coil of the second relay 132 is not energized, so that the normally closed contact switch of the second relay 132 is closed, so that the accessed high potential of the positive input terminal BAT + is transmitted to the positive output terminal BOUT +, and the accessed low potential of the negative input terminal BAT-is transmitted to the negative output terminal BOUT-. If the reverse connection occurs, the first diode D1 is turned off, the PMOS transistor Q1 is turned off, so that the positive input terminal BAT + and the positive output terminal BOUT + are in an off state, the second diode D2 is turned off, the NMOS transistor Q2 is turned off, so that the negative input terminal BAT-and the negative output terminal BOUT-are in an off state, thereby avoiding the occurrence of the condition that the system is damaged when the polarity of the input voltage is reversely connected, at this time, the third diode D3 is turned off, the fourth diode D4 is turned off, the coil of the second relay 132 is not electrified, and therefore, the normally closed contact switch of the second relay 132 is closed.

Illustratively, the first stage reverse-connection prevention protection circuit 10-1 may be the first reverse-connection prevention protection circuit 11 and fails. The second stage reverse connection prevention protection circuit 10-2 may be the second reverse connection prevention protection circuit 12 and is disabled. The third stage reverse connection prevention protection circuit 10-3 can be a third reverse connection prevention protection circuit 13 and is not invalid. If reverse connection occurs, the first-stage reverse connection prevention protection circuit 10-1 does not work, the second-stage reverse connection prevention protection circuit 10-2 does not work, the third diode D3 is conducted, the fourth diode D4 is conducted, and the coil of the second relay 132 is electrified, so that the normally closed contact switch of the second relay 132 is disconnected, the anode input terminal BAT + and the anode output terminal BOUT + are in a disconnected state, and the condition that the system is damaged when the polarity of input voltage is reversely connected is avoided.

Optionally, on the basis of the above embodiment, fig. 3 is a schematic structural diagram of another reverse connection prevention protection device provided in the embodiment of the present invention, the reverse connection prevention protection device 1 further includes a first reverse connection alarm circuit 20, and a first end N1 and a second end N2 of the first reverse connection alarm circuit 20 are electrically connected to a positive input terminal BAT + and a negative input terminal BAT-of the reverse connection prevention protection device 1, respectively; the first reverse connection alarm circuit 20 is used for alarming when reverse connection is performed.

Wherein the first reverse connection alarm circuit 20 may comprise at least one of: light emitting diode and buzzer to realize acousto-optic alarm. If no reverse connection occurs, the first reverse connection alarm circuit 20 does not alarm.

Optionally, on the basis of the foregoing embodiment, with reference to fig. 3, the first reverse connection alarm circuit 20 includes a first light emitting diode LED1, a sixth diode D6, and a fifth resistor R5, wherein the first light emitting diode LED1, the sixth diode D6, and the fifth resistor R5 are connected in series, and two ends of the series are electrically connected to the first end N1 and the second end N2 of the first reverse connection alarm circuit 20, respectively.

The fifth resistor R5 has a current limiting function. If the reverse connection occurs, the sixth diode D6 is turned on, and the first light emitting diode LED1 emits light to realize an alarm. If no reverse connection occurs, the sixth diode D6 is turned off, and the first light emitting diode LED1 does not emit light. The first light emitting diode LED1 and the sixth diode D6 are turned on from the second end N2 to the first end N1 of the first reverse alarm circuit 20.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 3, the reverse connection prevention protection device 1 further includes a second reverse connection alarm circuit 30, a first end N3 and a second end N4 of the second reverse connection alarm circuit 30 are electrically connected to the first output Vo1 and the second output Vo2 of the first-stage reverse connection prevention protection circuit 11-1, respectively, and the second reverse connection alarm circuit 30 is configured to alarm when the first-stage reverse connection prevention protection circuit 10-1 fails and is in reverse connection, so as to prompt that the first-stage reverse connection prevention protection circuit 10-1 fails and reverse connection occurs.

Wherein the second reverse connection alarm circuit 30 may comprise at least one of: light emitting diode and buzzer to realize acousto-optic alarm. The first reverse connection alarm circuit 20 and the second reverse connection alarm circuit 30 are identical or similar in structure. If reverse connection occurs and the first-stage reverse connection prevention protection circuit 10-1 does not fail, the second reverse connection alarm circuit 30 does not alarm. If no reverse connection occurs, the second reverse connection alarm circuit 30 does not alarm.

Optionally, on the basis of the above embodiment, with continued reference to fig. 3, the second reverse connection alarm circuit 30 includes a seventh diode D7, an eighth diode D8, a low dropout linear regulator 31 and a buzzer 32, wherein a cathode of the seventh diode D7 is electrically connected to the first terminal N3 of the second reverse connection alarm circuit 30; the anode of the seventh diode D7 is electrically connected to the negative input Vi-of the low dropout linear regulator 31; the anode of the eighth diode D8 is electrically connected to the second terminal N4 of the second reverse alarm circuit 30; the cathode of the eighth diode D8 is electrically connected to the positive input Vi + of the low dropout linear regulator 31; the first end and the second end of the buzzer 32 are electrically connected with the positive output end Vo + and the negative output end Vo-of the low dropout regulator 31, respectively.

When the first-stage reverse connection prevention protection circuit 10-1 fails and is reversely connected, the seventh diode D7 is conducted, the eighth diode D8 is conducted, the low dropout linear regulator 31 works, and the buzzer 32 makes a sound to realize alarming. When the first-stage reverse connection prevention protection circuit 10-1 is not in failure and is in reverse connection, the first diode D1 is turned off, the second diode D2 is turned off, the voltages of the first end N3 and the second end N4 of the second reverse connection alarm circuit 30 are zero, the seventh diode D7 is turned off, the eighth diode D8 is turned off, the low dropout linear regulator 31 does not work, and the buzzer 32 does not make a sound.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 3, the first reverse connection protection circuit 11 further includes a sixth resistor R6, and the gate of the PMOS transistor Q1 is electrically connected to the first end of the sixth resistor R6; the second terminal of the sixth resistor R6, the anode of the first zener diode Z1, and the second terminal of the first resistor R1 are electrically connected to the first terminal of the second resistor R1. The sixth resistor R6 has a current limiting function.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 3, the second reverse connection prevention protection circuit 12 further includes a seventh resistor R7, and the gate of the NMOS transistor Q2 is electrically connected to the first end of the seventh resistor R7; a second terminal of the seventh resistor R7, a cathode of the second zener diode Z2, and a second terminal of the third resistor R3 are electrically connected to the first terminal of the fourth resistor R4. The seventh resistor R7 has a current limiting function.

The embodiment of the utility model provides a vehicle mounted power. Fig. 4 is a schematic structural diagram of an onboard power supply provided by an embodiment of the present invention. This vehicle mounted power includes: energy storage module 2, direct current are transferred to current conversion circuit 3, second relay 4 and the utility model discloses arbitrary embodiment provides prevents reverse connection protection device 1.

The energy storage module 2 is electrically connected with a positive input terminal BAT + and a negative input terminal BAT-of the reverse connection prevention protection device 1, and a positive output terminal BOUT + of the reverse connection prevention protection device 1 is electrically connected with a first input terminal of the direct current-to-alternating current conversion circuit 3; the negative output terminal BOUT + of the reverse connection prevention protection device 1 is electrically connected with the second input terminal of the direct current to alternating current conversion circuit 3; the output end of the direct current-to-alternating current conversion circuit 3 is electrically connected with the output end of the vehicle-mounted power supply through a normally closed contact switch of the second relay 4; the first end and the second end of the coil of the second relay 4 are electrically connected with the first alternating current power supply end L and the second alternating current power supply end N respectively, and the first alternating current power supply end L and the second alternating current power supply end N are electrically connected with the output end (such as Out1 and Out2 in fig. 4) of the vehicle-mounted power supply through the normally open contact switch of the second relay 4.

The energy storage module 2 may include at least one of the following: batteries and supercapacitors, etc. The second relay 4 may be a double pole double throw ac relay. The first ac power supply terminal L may be connected to a live line of the utility power. The second ac power supply terminal N may be connected to the neutral line of the mains supply. The dc-ac conversion circuit 3 may include a boost circuit and an inverter, wherein an input end of the boost circuit is electrically connected to an input end of the dc-ac conversion circuit; the output end of the booster circuit is electrically connected with the input end of the inverter; the output end of the inverter is electrically connected with the output end of the DC-to-AC conversion circuit.

The embodiment of the utility model provides a vehicle mounted power source includes the protection device that prevents joining conversely in above-mentioned embodiment, consequently the embodiment of the utility model provides a vehicle mounted power source also possesses the beneficial effect that the above-mentioned embodiment described, and here is no longer repeated.

Optionally, on the basis of the foregoing embodiment, fig. 5 is a schematic structural diagram of another vehicle-mounted power supply provided by the embodiment of the present invention, where the vehicle-mounted power supply further includes: and a wireless energy transmitting device 5, wherein an input end of the wireless energy transmitting device 5 is electrically connected with the energy storage module 2, and the wireless energy transmitting device 5 is used for transmitting energy to the mobile terminal 100 provided with the wireless energy receiving device 101 so as to wirelessly charge the mobile terminal 100.

The wireless energy transmitting device 5 may be an electromagnetic induction type wireless energy transmitting device, a magnetic resonance type wireless energy transmitting device, or a radio wave type wireless energy transmitting device. The wireless energy receiving device 101 may be an electromagnetic induction type wireless energy receiving device, a magnetic resonance type wireless energy receiving device, or a radio wave type wireless energy receiving device. The mobile terminal 100 may include at least one of: mobile phones, notebook computers, tablet computers, and portable Digital Radiography (DR) devices. A battery is also provided in the portable digital X-ray photographing apparatus for storing energy received by the wireless energy receiving device 101 in the portable digital X-ray photographing apparatus from the wireless energy transmitting device 5 of the in-vehicle power supply. The portable digital X-ray photography equipment is also provided with a flat panel detector. In the portable digital X-ray photographing apparatus, the wireless energy receiving device 101 is electrically connected to a battery through an ac-to-dc converter, and the battery can be used to supply power to the flat panel detector.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 5, the vehicle-mounted power supply further includes: and the first circuit breaker 7 is arranged between the energy storage module 2 and the positive input terminal BAT + and the negative input terminal BAT-of the reverse connection prevention protection device 1. Whether the energy storage module 2 is connected with the reverse connection prevention protection device 1 or not is achieved by controlling the connection and the disconnection of the first circuit breaker 7.

Optionally, on the basis of the foregoing embodiment, with continued reference to fig. 5, the vehicle-mounted power supply further includes: the first alternating current power supply end L and the second alternating current power supply end N are electrically connected with a normally open contact switch of the second relay 4 through the second circuit breaker 6; the first ac power supply terminal L and the second ac power supply terminal N are electrically connected to both ends of the coil of the second relay 4 via the second circuit breaker 6. And the on and off of the second circuit breaker 6 are controlled to realize the connection of the commercial power.

Optionally, on the basis of the above-mentioned embodiment, fig. 6 is a structural schematic diagram of a boost circuit provided by the embodiment of the present invention, the boost circuit may be a push-pull boost circuit, and the boost circuit may include: the circuit comprises a first capacitor, a first inductor L1, a first switch tube M1, a second switch tube M2, a first transformer T1, a single-phase bridge type uncontrollable rectifying circuit 311 and a second capacitor C2.

The first transformer T1 may include a first primary winding, a second primary winding, and a secondary winding, where a first end of the first primary winding and a first end of the second primary winding are electrically connected to the first inductor L1; the second end of the first inductor L1 and the first end of the first capacitor C1 are both connected to the positive output terminal BOUT + of the reverse-connection protection device 1; the second end of the first capacitor C1, the first pole of the first switch tube M1 and the first pole of the second switch tube M2 are electrically connected with the negative output terminal BOUT-of the reverse-connection prevention protection device 1; the second end of the first primary winding is electrically connected with the second pole of the first switching tube M1; the second end of the second primary winding is electrically connected with the second pole of the second switching tube M2; the first end and the second end of the secondary winding are respectively and electrically connected with the first input end and the second input end of the single-phase bridge type uncontrollable rectifying circuit 311; a first output terminal and a second output terminal of the single-phase bridge uncontrollable rectifying circuit 311 are electrically connected to a first terminal and a second terminal of the second capacitor C2, respectively. The first end of the first primary winding and the second end of the second primary winding are homonymous ends.

Optionally, on the basis of the foregoing embodiment, fig. 7 is a schematic structural diagram of an inverter provided by an embodiment of the present invention, where the inverter may be a single-phase inverter, and the inverter may include: and each two switching tubes are connected into a bridge arm, and the middle points of the two bridge arms are electrically connected with the output end of the inverter through a filter circuit. The filter circuit comprises a second inductor L and a third capacitor C3. The switch tube VT1 and the switch tube VT4 are closed, the switch tube VT2 and the switch tube VT3 are disconnected, the output voltage of the bridge circuit is U, the U is a positive value, and the U is the input voltage of the bridge circuit; the switch tube VT1 and the switch tube VT4 are disconnected, the switch tube VT2 and the switch tube VT3 are closed, and the output voltage of the bridge circuit is-U; when the switching tubes VT1, VT4 and VT2, VT3 are alternately switched at the frequency fs, an alternating voltage waveform (i.e., a square wave with alternating positive and negative) is obtained, and the period Ts thereof is 1/fs, so that the direct-current voltage is changed into the alternating-current voltage. The alternating voltage contains higher harmonics and is filtered by a filter circuit to obtain sine wave voltage. There is a loss in the switching device: conduction losses (conduction losses) and commutation losses (commutation losses) and gate losses (gate losses). In which gate losses are negligible, while conduction losses and commutation losses increase with increasing switching frequency. To reduce losses, the upper tubes VT1 and VT3 are placed in the power frequency cycle. The lower tubes VT2 and VT4 are arranged in a high-frequency period, so that the switching loss is greatly reduced, and the working efficiency of the whole machine is improved.

Optionally, the inverter may further include: and the control circuit is electrically connected with the gates of the four switching tubes VT1, VT2, VT3 and VT4 and is used for outputting driving signals so as to control the on and off of the four switching tubes VT1, VT2, VT3 and VT 4. The inverter can also comprise an overcurrent protection circuit, an overload protection circuit, an overtemperature protection circuit, a direct current overvoltage and undervoltage protection circuit, an output short-circuit protection circuit and the like.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (10)

1. An anti-reverse-connection protection device is characterized by comprising:

the protection circuit comprises at least two cascaded reverse connection prevention protection circuits, wherein a first input end of a first-stage reverse connection prevention protection circuit is electrically connected with a positive input end of the reverse connection prevention protection device; the second input end of the first-stage reverse connection prevention protection circuit is electrically connected with the negative input end of the reverse connection prevention protection device; the first output end of the previous stage reverse connection prevention protection circuit is electrically connected with the first input end of the next stage reverse connection prevention protection circuit; the second output end of the previous stage reverse connection prevention protection circuit is electrically connected with the second input end of the next stage reverse connection prevention protection circuit; the first output end of the last stage reverse connection prevention protection circuit is electrically connected with the positive output end of the reverse connection prevention protection device; and the second output end of the last stage of reverse connection prevention protection circuit is electrically connected with the negative output end of the reverse connection prevention protection device.

2. The reverse-connection prevention protection device according to claim 1, wherein the at least two cascaded reverse-connection prevention protection circuits comprise: at least one first reverse-connection prevention protection circuit,

the first reverse connection prevention protection circuit comprises a PMOS (P-channel metal oxide semiconductor) tube, a first diode, a first voltage stabilizing diode, a first resistor and a second resistor, wherein a drain electrode of the PMOS tube and an anode of the first diode are electrically connected with a first input end of the first reverse connection prevention protection circuit; the source electrode of the PMOS tube, the cathode of the first diode, the cathode of the first voltage stabilizing diode and the first end of the first resistor are electrically connected with the first output end of the first reverse connection prevention protection circuit; the grid electrode of the PMOS tube, the anode of the first voltage stabilizing diode and the second end of the first resistor are electrically connected with the first end of the second resistor; the second end of the second resistor and the second input end of the first reverse-connection prevention protection circuit are electrically connected with the second output end of the first reverse-connection prevention protection circuit.

3. The reverse-connection prevention protection device according to claim 1, wherein the at least two cascaded reverse-connection prevention protection circuits comprise: at least one second reverse-connection prevention protection circuit,

the second reverse connection prevention protection circuit comprises an NMOS (N-channel metal oxide semiconductor) tube, a second diode, a second voltage stabilizing diode, a third resistor and a fourth resistor, wherein the drain electrode of the NMOS tube and the cathode of the second diode are electrically connected with the second input end of the second reverse connection prevention protection circuit; the source electrode of the NMOS tube, the anode of the second diode, the anode of the second voltage stabilizing diode and the first end of the third resistor are electrically connected with the second output end of the second reverse connection prevention protection circuit; the grid electrode of the NMOS tube, the cathode of the second voltage stabilizing diode and the second end of the third resistor are electrically connected with the first end of the fourth resistor; the second end of the fourth resistor and the first input end of the second reverse-connection prevention protection circuit are electrically connected with the first output end of the second reverse-connection prevention protection circuit.

4. The reverse-connection prevention protection device according to claim 1, wherein the at least two cascaded reverse-connection prevention protection circuits comprise: at least one third protection circuit is connected in reverse,

the third protection circuit comprises a third diode, a fourth diode, a direct current-to-direct current voltage reduction circuit, a first relay and a fifth diode, wherein the cathode of the third diode and the first end of the normally closed contact switch of the first relay are electrically connected with the first input end of the third protection circuit; the second end of the normally closed contact switch of the first relay is electrically connected with the first output end of the third protection reverse connection protection circuit; the anode of the third diode is electrically connected with the negative input end of the direct current-to-direct current voltage reduction circuit; the anode of the fourth diode and the second input end of the third protection reverse-connection protection circuit are electrically connected with the second output end of the third protection reverse-connection protection circuit; the cathode of the fourth diode is electrically connected with the anode input end of the direct current-to-direct current voltage reduction circuit; the first end of the coil of the first relay and the cathode of the fifth diode are electrically connected with the anode output end of the direct current-to-direct current voltage reduction circuit; and the second end of the coil of the first relay and the anode of the fifth diode are electrically connected with the negative output end of the direct current-to-direct current voltage reduction circuit.

5. The reverse connection prevention protection device according to claim 1, further comprising a first reverse connection alarm circuit, wherein a first end and a second end of the first reverse connection alarm circuit are electrically connected with a positive input end and a negative input end of the reverse connection prevention protection device respectively, and the first reverse connection alarm circuit is used for giving an alarm when in reverse connection.

6. The reverse connection prevention protection device according to claim 5, wherein the first reverse connection alarm circuit comprises a first light emitting diode, a sixth diode and a fifth resistor, wherein the first light emitting diode, the sixth diode and the fifth resistor are connected in series, and two ends of the series connection are respectively and electrically connected with a first end and a second end of the first reverse connection alarm circuit.

7. The reverse connection prevention protection device according to claim 1, further comprising a second reverse connection alarm circuit, wherein a first end and a second end of the second reverse connection alarm circuit are electrically connected with a first output end and a second output end of the first stage reverse connection prevention protection circuit respectively, and the second reverse connection alarm circuit is used for alarming when the first stage reverse connection prevention protection circuit fails and is reversely connected.

8. The reverse connection prevention protection device according to claim 7, wherein the second reverse connection alarm circuit comprises a seventh diode, an eighth diode, a low dropout linear regulator and a buzzer, wherein a cathode of the seventh diode is electrically connected with a first end of the second reverse connection alarm circuit; the anode of the seventh diode is electrically connected with the negative input end of the low dropout regulator; the anode of the eighth diode is electrically connected with the second end of the second reverse connection alarm circuit; the cathode of the eighth diode is electrically connected with the positive input end of the low dropout regulator; and the first end and the second end of the buzzer are respectively and electrically connected with the positive output end and the negative output end of the low-dropout linear regulator.

9. An onboard power supply, comprising: an energy storage module, a DC-to-AC conversion circuit, a second relay and the reverse connection prevention protection device of any one of claims 1-8,

the energy storage module is electrically connected with a positive input end and a negative input end of the reverse connection prevention protection device, and a positive output end of the reverse connection prevention protection device is electrically connected with a first input end of the direct current-to-alternating current conversion circuit; the negative electrode output end of the reverse connection prevention protection device is electrically connected with the second input end of the direct current-to-alternating current conversion circuit; the output end of the direct current-to-alternating current conversion circuit is electrically connected with the output end of the vehicle-mounted power supply through a normally closed contact switch of the second relay; and a first end and a second end of a coil of the second relay are respectively and electrically connected with a first alternating current power supply end and a second alternating current power supply end, and the first alternating current power supply end and the second alternating current power supply end are electrically connected with the output end of the vehicle-mounted power supply through a normally open contact switch of the second relay.

10. The vehicular power supply according to claim 9, further comprising: the energy storage module is electrically connected with the input end of the wireless energy transmitting device, and the wireless energy transmitting device is used for transmitting energy to a mobile terminal provided with a wireless energy receiving device so as to wirelessly charge the mobile terminal;

the mobile terminal comprises at least one of the following: mobile phones, notebook computers, tablet computers and portable digital X-ray photography equipment.

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