Cashbox driving circuit and cashbox

Abstract

The invention provides a cashbox driving circuit and a cashbox, and the circuit comprises a voltage regulation circuit which is used for converting a host input voltage into an electromagnetic valve driving voltage of the cashbox; the load switch is connected with the voltage regulating circuit and is used for outputting the electromagnetic valve driving voltage to an electromagnetic valve of the cashbox; the enabling circuit is connected with the load switch and is used for generating an enabling signal for controlling the load switch according to the cashbox control signal output by the host; when the host starts the cashbox, the enable signal enables the load switch; otherwise, turning off the load switch. According to the invention, the requirement of the cashbox driving current is reduced, and the adaptation degree of the host and the cashbox is improved; and cashbox control signal abnormity protection and electromagnetic valve over-temperature protection are also provided, so that the automatic protection function of the cashbox is better realized.

Description

Technical Field

[0001] The present invention relates to the field of circuits, and particularly to a cash box drive circuit and a cash box. Background Art

[0002] There are cash boxes with different drive voltages on the market. In order to adapt to different cash boxes, a voltage regulating circuit for converting the host input voltage into the cash box drive voltage needs to be included inside the cash box. In an existing technology, as Figure 7 shown, the cash box includes a voltage regulating circuit, an enabling circuit, and a solenoid valve. The solenoid valve is used to pull the lock body to open the cash box when powered on. The enabling circuit directly controls the voltage regulating circuit. When the host does not open the cash box, the enabling circuit turns off the voltage regulating circuit; when the host opens the cash box, the voltage regulating circuit and the output drive voltage are simultaneously started to be supplied to the solenoid valve, and the solenoid valve then drives the cash box to open.

[0003] Since when opening the cash box, it is necessary to simultaneously start the voltage regulating circuit and output the drive voltage to the solenoid valve, a relatively large instantaneous current is required, and some hosts with limited output peak current cannot open the cash box. For this reason, this application improves the existing cash box drive circuit. Summary of the Invention

[0004] One of the purposes of the present invention is to overcome the deficiencies existing in the prior art, and provide a cash box drive circuit and a cash box.

[0005] The technical solution provided by the present invention is as follows:

[0006] A cash box drive circuit includes: a voltage regulating circuit for converting the host input voltage into the solenoid valve drive voltage of the cash box;

[0007] A load switch, connected to the voltage regulating circuit, for outputting the solenoid valve drive voltage to the solenoid valve of the cash box;

[0008] An enabling circuit, connected to the load switch, for generating an enabling signal for controlling the load switch according to the cash box control signal output by the host; when the host opens the cash box, the enabling signal enables the load switch; otherwise, the load switch is turned off.

[0009] In some embodiments, the cash box control signal is a low-level effective pulse signal;

[0010] The enabling circuit is further configured to, when the cash box control signal is low, the enabling signal is high to enable the load switch; when the cash box control signal is high, the enabling signal is low to turn off the load switch.

[0011] In some embodiments, the enabling circuit includes a timeout protection enabling circuit, which is configured to flip the enabling signal from high level to low level when the duration of the cash box control signal being at low level exceeds a preset time.

[0012] In some embodiments, the timeout protection enabling circuit includes:

[0013] A first PMOS transistor Q1, a second NMOS transistor Q2, a fifth capacitor C5, a seventh resistor R7, a tenth resistor R10, an eleventh resistor R11, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17;

[0014] A first power supply voltage is respectively connected to one ends of the fourteenth resistor R14 and the fifteenth resistor R15. The other end of the fifteenth resistor R15 is respectively connected to one end of the fifth capacitor C5 and one end of the sixteenth resistor R16. The other end of the sixteenth resistor R16 is connected to the cash box control signal. The other end of the fifth capacitor C5 is respectively connected to the gate of the second NMOS transistor Q2 and one end of the seventeenth resistor R17. The other end of the seventeenth resistor R17 is connected to the other end of the sixteenth resistor R16. The other end of the fourteenth resistor R14 is connected to the drain of the second NMOS transistor Q2. The source of the second NMOS transistor Q2 is connected to the other end of the seventeenth resistor R17;

[0015] A second power supply voltage is respectively connected to one end of the tenth resistor R10 and the source of the first PMOS transistor Q1. The drain D of the first PMOS transistor Q1 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to the ground through the eleventh resistor R11. The other end of the tenth resistor R10 is connected to the gate of the first PMOS transistor Q1. The gate of the first PMOS transistor Q1 is connected to the drain of the second NMOS transistor Q2 through the thirteenth resistor R13; The connection point of the seventh resistor R7 and the eleventh resistor R11 is connected to the enabling signal.

[0016] In some embodiments, the enabling circuit further includes an over-temperature protection enabling circuit, which is configured to detect the temperature of the solenoid valve. When the temperature of the solenoid valve is too high, it pulls down the enabling signal to make the enabling signal lower than the minimum enabling voltage of the load switch.

[0017] In some embodiments, the over-temperature protection enabling circuit includes a thermistor, whose resistance value changes following the temperature of the solenoid valve, and one end of the thermistor is connected to the enabling signal.

[0018] In some embodiments, the thermistor is a negative temperature coefficient thermistor, and the other end of the thermistor is grounded.

[0019] The present invention also provides a cash box, comprising:

[0020] A cash box driving circuit according to any one of the foregoing embodiments, configured to output a solenoid valve driving voltage when the host enables the cash box;

[0021] A solenoid valve, configured to control the opening and closing of the cash box according to the solenoid valve driving voltage.

[0022] The cash box driving circuit and the cash box provided by the present invention can at least bring the following beneficial effects:

[0023] 1. By always starting the voltage regulating circuit and only controlling the output of the driving voltage to the solenoid valve, the present invention reduces the instantaneous current requirement when opening the cash box, thereby reducing the output current requirement for the host and improving the compatibility between the host and the cash box.

[0024] 2. When the cash box control signal is abnormal, the present invention can timely switch the enable signal from the valid level to the invalid level, forcibly close the load switch, and cut off the power supply to the solenoid valve, improving the safety of the cash box.

[0025] 3. The present invention provides over-temperature protection for the solenoid valve, improving the safety of the cash box. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above characteristics, technical features, advantages and implementation manners of a cash box driving circuit and a cash box will be further described below in a clear and understandable manner in conjunction with the drawings in the preferred embodiments.

[0027] Figure 1 is a schematic structural diagram of an embodiment of a cash box driving circuit of the present invention;

[0028] Figure 2 is Figure 1 a schematic structural diagram of an embodiment of the enable circuit in

[0029] Figure 3 is a circuit diagram of an embodiment of the timeout protection enable circuit;

[0030] Figure 4 is a circuit diagram of an embodiment of the over-temperature protection enable circuit;

[0031] Figure 5 is a schematic structural diagram of an embodiment of a cash box of the present invention;

[0032] Figure 6 is a schematic structural diagram of another embodiment of a cash box of the present invention;

[0033] Figure 7 It is a schematic structural diagram of an existing cash box. Specific Embodiments

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts, and other embodiments can also be obtained.

[0035] To make the drawings concise, only the parts related to the present invention are schematically shown in each drawing, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, components with the same structure or function are only schematically drawn one of them, or only one of them is marked. In this article, "one" not only means "only this one", but also means "more than one" situation.

[0036] An embodiment of the present invention, as Figures 1 to 4 shown, a cash box drive circuit 100 includes:

[0037] A voltage regulating circuit 110 for converting the host input voltage into the solenoid valve drive voltage of the cash box;

[0038] A load switch 120 connected to the voltage regulating circuit 110 for outputting the solenoid valve drive voltage to the solenoid valve 200 of the cash box;

[0039] An enabling circuit 130 connected to the load switch 120 for generating an enabling signal for controlling the load switch 120 according to the cash box control signal output by the host; when the host opens the cash box, the enabling signal enables the load switch; otherwise, the load switch is closed.

[0040] Specifically, in order to meet the requirements of the drive voltage of the cash box (such as 9V, 12V, 24V, etc.), the input voltage from the host is converted into the drive voltage of the solenoid valve of the cash box through the voltage regulating circuit. The voltage regulating circuit can be a boost circuit or a buck circuit, depending on the magnitude relationship between the host input voltage and the solenoid valve drive voltage. If the host input voltage is greater than the solenoid valve drive voltage, a buck circuit is used. If the host input voltage is less than the solenoid valve drive voltage, a boost circuit is used. The voltage regulating circuit is always on, so there is always an effective solenoid valve drive voltage.

[0041] Whether the effective solenoid valve drive voltage is output to the solenoid valve is controlled by a load switch. The load switch controls the output of the solenoid valve drive voltage according to the enable signal. When the enable signal is valid, the load switch is enabled, and the solenoid valve drive voltage from the voltage regulating circuit is output to the solenoid valve; otherwise, the load switch is turned off and no drive voltage is output to the solenoid valve. When the drive voltage is output to the solenoid valve, the solenoid valve is energized, and the electromagnetic coil generates an electromagnetic suction force to suck the metal bolt into the coil interior, pulling the lock body to open the cash box; when the power supply of the solenoid valve is disconnected, the magnetic field disappears, and the metal bolt and the lock body return to their original positions under the action of the reset device, and the cash box is closed.

[0042] The validity of the enable signal is controlled by an enable circuit. When the cash box control signal from the host is valid, the enable signal is valid; when the cash box control signal is invalid, the enable signal is invalid. For example, assuming that the valid level of the cash box control signal is a low level and the valid level of the enable signal is a high level, when the cash box control signal changes from a high level (invalid level) to a low level (valid level), the enable signal also changes to the valid level (high level); when the cash box control signal changes from a low level (valid level) to a high level (invalid level), the enable signal also changes to the invalid level (low level).

[0043] In this embodiment, when opening the cash box, it is not necessary to start the voltage regulating circuit and output the drive voltage to the solenoid valve at the same time; by always starting the voltage regulating circuit, a stable and effective solenoid valve drive voltage can be obtained; and only the output drive voltage to the solenoid valve is controlled, reducing the instantaneous current requirement when opening the cash box, thereby reducing the output current requirement for the host and improving the matching degree between the host and the cash box.

[0044] In one embodiment, the cash box control signal is a low-level effective pulse signal, and the enable signal is high-level effective; the enable circuit is further configured to enable the load switch when the cash box control signal is at a low level and the enable signal is at a high level; when the cash box control signal is at a high level, the enable signal is at a low level, and the load switch is turned off.

[0045] In one embodiment, the cash box control signal is a low-level effective pulse signal, and the enable signal is high-level effective; the enable circuit 130 includes a timeout protection enable circuit 131, as Figure 2 shown, the timeout protection enable circuit 131 is configured to flip the enable signal from a high level to a low level when the duration of the cash box control signal being continuously at a low level exceeds a preset time.

[0046] Specifically, when the cash box control signal is at a low level, the enable signal is at a high level, enabling the load switch, and the load switch outputs the solenoid valve drive voltage from the voltage regulating circuit to the solenoid valve in the enabled state.

[0047] However, in some abnormal situations, such as when the host crashes or the host abnormality causes the cash box control signal to be abnormal, the cash box control signal remains in the low-level effective state all the time, and the enable signal is also in the effective state. If the enable signal is not timely flipped from the effective level to the invalid level, the load switch will always be on, making the solenoid valve always in the energized state. After a long time, the solenoid valve will heat up and smoke, posing a safety hazard. Therefore, in order to improve the safety of the solenoid valve, a timeout protection enable circuit is designed. When the duration of the cash box control signal at the effective level exceeds the preset time, the enable signal is timely switched from the effective level to the invalid level, closing the load switch and cutting off the power supply to the solenoid valve.

[0048] This embodiment improves the automatic protection function of the cash box.

[0049] In one embodiment, as Figure 3 shown, the timeout protection enable circuit 131 specifically includes:

[0050] The first PMOS transistor Q1, the second NMOS transistor Q2, the fifth capacitor C5, the seventh resistor R7, the tenth resistor R10, the eleventh resistor R11, the thirteenth resistor R13, the fourteenth resistor R14, the fifteenth resistor R15, the sixteenth resistor R16, and the seventeenth resistor R17.

[0051] The first power supply voltage VCC1 is respectively connected to one end of the fourteenth resistor R14 and the fifteenth resistor R15. The other end of the fifteenth resistor R15 is respectively connected to one end of the fifth capacitor C5 and the sixteenth resistor R16. The other end of the sixteenth resistor R16 is connected to the cash box control signal CashCtrl. The other end of the fifth capacitor C5 is respectively connected to the gate G of the second NMOS transistor Q2 and one end of the seventeenth resistor R17. The other end of the seventeenth resistor R17 is connected to the other end of the sixteenth resistor R16. The other end of the fourteenth resistor R14 is connected to the drain D of the second NMOS transistor Q2. The source S of the second NMOS transistor Q2 is connected to the other end of the seventeenth resistor R17.

[0052] The second power supply voltage VCC2 is respectively connected to one end of the tenth resistor R10 and the source S of the first PMOS transistor Q1. The drain D of the first PMOS transistor Q1 is connected to one end of the seventh resistor R7. The other end of the seventh resistor R7 is connected to the ground through the eleventh resistor R11. The other end of the tenth resistor R10 is connected to the gate G of the first PMOS transistor Q1. The gate G of the first PMOS transistor Q1 is connected to the drain D of the second NMOS transistor Q2 through the thirteenth resistor R13. The connection point of the seventh resistor R7 and the eleventh resistor R11 is connected to the enable signal.

[0053] The first power supply voltage VCC1 and the second power supply voltage VCC2 can be the same, for example, both are the solenoid valve drive voltage, or they can be different. This application does not limit it and can be other power supply voltages that meet the requirements.

[0054] Specifically, C5 and R17 form an RC differentiating circuit.

[0055] Assume that the effective level of the cash box control signal CashCtrl is low level, and the effective level of the enable signal is high level.

[0056] When the host wants to open the cash box, under normal circumstances, it will pull down the cash box control signal CashCtrl to make it at a low level (the same level as the ground GND) for a certain period of time, such as 100 ms. The first power supply voltage VCC1 is divided by R15 and R16, and the capacitor C5 is charged through the charge and discharge circuit. The voltage of the resistor R17 quickly reaches the peak value, which is greater than the conduction threshold of Q2. Q2 conducts, and the drain of Q2 becomes low level, making the gate voltage of Q1 lower than the source voltage. Q1 conducts, and the drain of Q1 is pulled up, making the enable signal Enable become high level, enabling the load switch, outputting the solenoid valve drive voltage, driving the solenoid valve to be energized, and opening the cash box.

[0057] When the cash box control signal CashCtrl becomes high level, the source voltage of Q2 becomes high level, and the voltage value between the gate and the source is less than the conduction threshold of Q2. Q2 turns off, the drain level of Q2 is pulled up, raising the gate voltage of Q1. Q1 turns off, and the drain of Q1 becomes low level, and the enable signal Enable becomes low, closing the output of the load switch.

[0058] When the host side crashes or the control is abnormal and keeps pulling down the CashCtrl signal, due to the small time constant of the RC differentiating circuit (less than the low-level pulse width of the CashCtrl signal), the voltage of the resistor R17 will drop within the preset time constant. When it drops below the conduction threshold of Q2, Q2 turns off, the drain level of Q2 is pulled up, raising the gate voltage of Q1. Q1 turns off, and the drain of Q1 becomes low level, and the enable signal Enable becomes low, closing the output of the load switch, thereby closing the solenoid valve and closing the cash box.

[0059] This embodiment provides a specific timeout protection enable circuit, which can, when detecting an abnormality in the cash box control signal (the duration of the continuous effective level exceeds the preset time), timely control the enable signal to flip from the effective level to the invalid level, thereby controlling the load switch to close, cutting off the power supply of the solenoid valve, and preventing the solenoid valve from overheating.

[0060] In one embodiment, the enable circuit further includes an over-temperature protection enable circuit 132 (such as Figure 2) The over-temperature protection enabling circuit 132 is used to detect the temperature of the solenoid valve. When the temperature of the solenoid valve is too high, for example, higher than the preset threshold, it pulls down the enabling signal to make the enabling signal lower than the minimum enabling voltage of the load switch.

[0061] Since it is easy to be dangerous when the temperature of the solenoid valve is too high, therefore, it is necessary to detect the temperature of the solenoid valve. When the temperature of the solenoid valve is too high, it pulls down the enabling signal to forcibly turn off the load switch, thereby cutting off the power supply of the solenoid valve to cool it down.

[0062] In one embodiment, the over-temperature protection enabling circuit includes a heat-conducting medium and a thermistor R1. A heat-conducting medium is pasted on one side of the solenoid valve F1, and the thermistor R1 is pasted on the side of the heat-conducting medium away from the solenoid valve F1.

[0063] The heat-conducting medium is used to conduct the temperature of the solenoid valve to the thermistor so that the thermistor can timely sense the temperature change of the solenoid valve. The heat-conducting medium can be a material with good heat-conducting performance and electrical insulation performance such as heat-conducting silicone grease and heat-conducting silica gel.

[0064] One end of the thermistor is connected to the enabling signal Enable, and its resistance value changes with the temperature of the solenoid valve. When the temperature of the solenoid valve is too high, as the resistance value of the thermistor changes, the level of the enabling signal is continuously pulled down. When the enabling signal is lower than the minimum enabling voltage of the load switch, the load switch is forcibly turned off and the power supply of the solenoid valve will be cut off.

[0065] The thermistor can be a negative temperature coefficient thermistor, that is, as the temperature increases, the resistance value becomes smaller. One end of it is connected to the enabling signal, and the other end is grounded. Assuming that the enabling signal is active high, when the temperature of the solenoid valve is too high, the resistance value of the thermistor in series between the enabling signal and the ground becomes smaller, reducing the impedance between the enabling signal and the ground, thereby pulling down the level of the enabling signal. When the level of the enabling signal is lower than the minimum enabling voltage required by the load switch, the load switch is forcibly turned off.

[0066] Such as Figure 4 , the heat-conducting medium uses heat-conducting silica gel, the thermistor R1 is a negative temperature coefficient thermistor, one end of it is grounded, and the other end is connected to the enabling signal Enable; one end of the solenoid valve F1 is connected to the load switch, and the other end is grounded.

[0067] This embodiment provides an over-temperature protection circuit. By making the enabling signal at an invalid level when the temperature of the solenoid valve is too high, the load switch is forcibly turned off, cutting off the power supply of the solenoid valve to cool it down.

[0068] One embodiment of the present invention, such as Figure 5 shown, a cash box includes:

[0069] A cash box driving circuit 100 described in any of the foregoing embodiments, which is configured to output a solenoid valve driving voltage to a solenoid valve when the host turns on the cash box;

[0070] The solenoid valve 200 is configured to control the opening and closing of the cash box according to the solenoid valve driving voltage. When the solenoid valve driving voltage is input, the solenoid valve controls the cash box to open; otherwise, it controls the cash box to close.

[0071] The present invention also provides another embodiment, as Figure 6 shown, a cash box, which internally includes a solenoid valve F1 and a step-down board. The step-down board includes a step-down circuit U1, a load switch U2, an over-time protection enabling circuit, and an over-temperature protection enabling circuit.

[0072] The working principle of the cash box driving is as follows:

[0073] The cash box interface cable is inserted into the host. The power input VCC_9V_12V_24V of the step-down circuit U1 is constantly powered by the host, and it can support power inputs of 9V, 12V, and 24V. The ground of the step-down board uses the pin1 host ground (GND_MB) in the cash box interface, so that the step-down circuit U1 is in a constant working state and outputs a DCDC_9V voltage (solenoid valve driving voltage). At this time, the solenoid valve F1 at the back end has not been started, and the instantaneous current output by the host power supply is not large, so it will not trigger the instantaneous large current protection mechanism of the host, enabling the host power supply to output stably and enabling the step-down circuit to operate stably.

[0074] When the host wants to open the cash box, it will pull down the cash box control signal CashCtrl for a preset time, such as 100 ms. After passing through the over-time protection enabling circuit (such as Figure 3 ), the enabling signal Enable is at a high level within the start time t1, enabling the U2 load switch chip, outputting a driving voltage of 9V to the solenoid valve, driving the solenoid valve F1 to be powered on, and opening the cash box.

[0075] If the host side freezes or the control is abnormal and keeps pulling down the cash box control signal, but because there is an over-time protection enabling circuit (such as Figure 3 ), the enabling signal Enable will become low after a certain time, closing the output of the U2 load switch, thereby closing the solenoid valve and stopping the solenoid valve from heating up.

[0076] If due to other faults or abnormal situations, the enabling signal Enable is always in an effective level state, the load switch is always open, and the solenoid valve is always passively powered on, the temperature of the solenoid valve will increase. Due to the over-temperature protection enabling circuit (such as Figure 4), A thermal resistor and heat-conducting silicone and other heat-conducting materials are closely attached to the solenoid valve coil inside the cash box. Once the solenoid valve heats up due to long-term power-on, the resistance of the thermal resistor R1 rapidly decreases from its normal value, pulling down the enable signal Enable. When the enable signal Enable is lower than the minimum enable voltage of the load switch U2, U2 will be forced to turn off, cutting off the power supply of the solenoid valve and causing it to cool down. After the temperature of the solenoid valve drops, the resistance value of R1 becomes larger, and the enable signal Enable can be greater than the minimum enable voltage of the load switch U2 again, without affecting the function of the host to open the cash box under normal circumstances.

[0077] The cash box provided in this embodiment has a two-stage power supply circuit, where the buck circuit is always on, and the load switch only controls the output of the solenoid valve drive voltage, improving the problem that some hosts that limit the output of instantaneous large currents cannot drive the cash box; it also has an over-temperature protection enable circuit and an overtime protection enable circuit to prevent abnormalities, protecting the cash box and avoiding potential safety hazards.

[0078] It should be noted that the above embodiments can be freely combined as needed. The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A cash box drive circuit, characterized in that, Comprising: A voltage regulating circuit for converting the host input voltage into the solenoid valve drive voltage of the cash box; A load switch connected to the voltage regulating circuit for outputting the solenoid valve drive voltage to the solenoid valve of the cash box; An enabling circuit connected to the load switch for generating an enabling signal for controlling the load switch according to the cash box control signal output by the host; when the host opens the cash box, the enabling signal enables the load switch; otherwise, the load switch is turned off.

2. The cash box drive circuit according to claim 1, wherein The cash box control signal is a low-level effective pulse signal; The enabling circuit is further configured to make the enabling signal be at a high level and enable the load switch when the cash box control signal is at a low level; and make the enabling signal be at a low level and turn off the load switch when the cash box control signal is at a high level.

3. The cash box drive circuit according to claim 2, wherein The enabling circuit includes a timeout protection enabling circuit, and the timeout protection enabling circuit is configured to make the enabling signal flip from a high level to a low level when the duration of the cash box control signal being at a low level exceeds a preset time.

4. The coin box drive circuit according to claim 3, wherein, The timeout protection enabling circuit includes: A first PMOS transistor Q1, a second NMOS transistor Q2, a fifth capacitor C5, a seventh resistor R7, a tenth resistor R10, an eleventh resistor R11, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17; A first power supply voltage is respectively connected to one ends of the fourteenth resistor R14 and the fifteenth resistor R15, the other end of the fifteenth resistor R15 is respectively connected to one ends of the fifth capacitor C5 and the sixteenth resistor R16, the other end of the sixteenth resistor R16 is connected to the cash box control signal, the other end of the fifth capacitor C5 is respectively connected to the gate of the second NMOS transistor Q2 and one end of the seventeenth resistor R17, the other end of the seventeenth resistor R17 is connected to the other end of the sixteenth resistor R16, the other end of the fourteenth resistor R14 is connected to the drain of the second NMOS transistor Q2, and the source of the second NMOS transistor Q2 is connected to the other end of the seventeenth resistor R17; A second power supply voltage is respectively connected to one end of the tenth resistor R10 and the source of the first PMOS transistor Q1, the drain D of the first PMOS transistor Q1 is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to the ground through the eleventh resistor R11, the other end of the tenth resistor R10 is connected to the gate of the first PMOS transistor Q1, and the gate of the first PMOS transistor Q1 is connected to the drain of the second NMOS transistor Q2 through the thirteenth resistor R13; the connection point of the seventh resistor R7 and the eleventh resistor R11 is connected to the enabling signal.

5. The cash box drive circuit according to any one of claims 1-4, wherein The enabling circuit further includes an over-temperature protection enabling circuit, which is used to detect the temperature of the solenoid valve. When the temperature of the solenoid valve is too high, it pulls down the enabling signal to make the enabling signal lower than the minimum enabling voltage of the load switch.

6. A cash box driving circuit according to claim 5, wherein the over-temperature protection enabling circuit includes a heat-conducting medium and a thermistor; one side of the heat-conducting medium is attached to the solenoid valve, and the other side is attached to the thermistor; the resistance value of the thermistor changes following the temperature of the solenoid valve, and one end of it is connected to the enabling signal.

7. A cash box driving circuit according to claim 6, wherein the thermistor is a negative temperature coefficient thermistor, and the other end of the thermistor is grounded.

8. A cash box, characterized in that, Comprising: A cash box driving circuit according to any one of claims 1-7, which is used to output a solenoid valve driving voltage when the host opens the cash box; A solenoid valve, which is used to control the opening and closing of the cash box according to the solenoid valve driving voltage.

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