Intelligent POS machine base and USB charging automatic switching charging circuit

Abstract

The utility model discloses a charging circuit capable of automatically switching between an intelligent POS machine base and USB charging. The circuit structurally comprises a charging chip U15, a charging chip U16, an MOS parasitic diode Q4, an MOS parasitic diode Q5, a triode Q6A, a triode Q6B, a triode Q7A, a triode Q7B, a bidirectional voltage stabilizing diode D14, a bidirectional voltage stabilizing diode D15, a capacitor C83, a capacitor C84, a capacitor C85, a resistor R84, a resistor R85, a resistor R86, a resistor R87, a resistor R88, a resistor R89, a resistor R90, a resistor R91, a resistor R92, a resistor R93, a resistor R94, a resistor R95, a resistor R161, a resistor R162, a resistor R163 and a resistor R166. Source electrodes of the Q4 and the Q5 are connected together to form a selection node, grid electrodes of the Q4 and the Q5 are controlled by the Q6A and the Q6B respectively, and either USB power supply or base power supply is achieved. The nEN end of the U15 is connected with DOCKVCC through the R92, when the base is inserted, the U15 is automatically closed, the base is preferentially used for power supply, and circulation is prevented; according to the circuit, the MOS parasitic diode characteristic is utilized, a conduction path is automatically switched when only a USB, only a base or double power supplies coexist, and stable charging of the POS machine is ensured.

Description

Technical Field

[0001] This utility model relates to the field of POS machine charging technology, and in particular to an intelligent POS machine base and a charging circuit with automatic USB charging switching. Background Technology

[0002] In today's digital business world, POS machines play a crucial role in the transaction process, and the charging dock is key to their stable operation. Charging the dock has extraordinary significance:

[0003] (1) Convenience: No need to find an extra charging cable and charger. Simply place the POS machine on the base to start charging. It is easy to operate.

[0004] (2) Stability: It can provide more stable charging support for POS machines and reduce charging interruptions caused by cable pulling or improper placement during the charging process.

[0005] (3) Interface protection: It can prevent the POS machine charging interface from being worn down by frequent plugging and unplugging of the charging cable, thus extending the service life of the interface. Long-term use of plug-and-play charging can easily cause the interface to loosen, while charging with a base can effectively reduce the occurrence of this situation.

[0006] (4) Unified Management: Multiple POS machines can use the same charging base for charging, which facilitates centralized management and maintenance. For large shopping malls or supermarkets with multiple cash registers, a unified charging base makes it easier to manage the charging equipment.

[0007] (5) Ensure continuous operation: Ensure that the POS machine always has sufficient power so that it can be put into use at any time and that transactions are not affected by insufficient power.

[0008] (6) Improve work efficiency: It saves time in finding charging equipment and connecting charging cables, allowing staff to focus more on business processing.

[0009] (7) Extend battery life: Proper charging methods help optimize battery performance and extend the overall lifespan of the battery. Correct charging modes can reduce battery wear and tear, and lower the frequency and cost of battery replacements.

[0010] (8) Improve safety: Proper charging docks usually have safety features such as overcharge protection, reducing safety hazards caused by overcharging.

[0011] To further enhance the ease of use of POS machines, they are now compatible with USB charging. However, charging via USB and dock simultaneously can cause power circulation issues due to voltage inconsistencies. Power circulation not only increases system losses but also affects the stable operation of the device, thus impacting the normal operation of the POS machine. Utility Model Content

[0012] The purpose of this invention is to provide an intelligent POS machine base and a charging circuit with automatic USB charging switching, thereby solving the aforementioned problems in the prior art.

[0013] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0014] A smart POS machine base and a charging circuit with automatic USB charging switching, including charging chip U15, charging chip U16, MOS parasitic diode Q4, MOS parasitic diode Q5, transistor Q6A, transistor Q6B, transistor Q7A, transistor Q7B, bidirectional Zener diode D14, bidirectional Zener diode D15, capacitor C83, capacitor C84, capacitor C85, resistor R84, resistor R85, resistor R86, resistor R87, resistor R88, resistor R89, resistor R90, resistor R91, resistor R92, resistor R93, resistor R94, resistor R95, resistor R161, resistor R162, resistor R163, and resistor R166;

[0015] The IN terminal of the charging chip U15 is connected to capacitor C84 and VBUS1, and the other end of capacitor C84 is connected to GND; the nEN terminal of the charging chip U15 is connected to one end of resistor R94, and the other end of resistor R94 is connected to GND; a resistor R92 is connected between the nEN terminal of the charging chip U15 and resistor R94, and resistor R92 is connected to DOCK_VCC.

[0016] The OUT terminal of the charging chip U15 is connected to one end of resistor R163. VBUS is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R163 is connected to the base of transistor Q7A. The collector of transistor Q7A is connected to one end of resistor R85. The other end of resistor R85 is connected to LDO. TYPE-C is connected between the collector of transistor Q7A and resistor R85. The emitter of transistor Q7A is grounded. Resistor R166 is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R166 is connected to one end of capacitor C83 and then to GND. The other end of capacitor C83 is connected to DC IN.

[0017] The gate of the MOS parasitic diode Q4 is connected to the collector of the transistor Q6A, and the source of the MOS parasitic diode Q4 is connected to the source of the MOS parasitic diode Q5. The drain of Q4 is connected to the OUT terminal of the charging chip U15. The gate of the MOS parasitic diode Q5 is connected to resistor R88, the other end of resistor R88 is connected to resistor R90, the other end of resistor R90 is connected to the base of transistor Q6A, and the emitter of transistor Q6A is connected to GND.

[0018] A bidirectional Zener diode D14 and a resistor R86 are connected between the gate of the MOS parasitic diode Q4 and the collector of the transistor Q6A. The other end of the bidirectional Zener diode D14 is connected to GND. The other end of the resistor R86 is connected between the MOS parasitic diodes Q4 and Q5. A bidirectional Zener diode D15 is connected between the MOS parasitic diode Q5 and the resistor R88. The other end of the bidirectional Zener diode D15 is connected to GND.

[0019] The DCI N is connected to the source of MOS parasitic diode Q4 and the source of MOS parasitic diode Q5, and then connected to resistor R87. Resistor R87 is connected to resistors R88 and R90, and then connected to the collector of transistor Q6B. The emitter of transistor Q6B is connected to GND. The base of transistor Q6B is connected to resistor R91. The other end of resistor R91 is connected to DOCK_VCC.

[0020] The DOCK_VCC is connected to resistors R95 and R93. The other end of resistor R95 is connected to GND. The other end of resistor R93 is connected to the base of transistor Q7B. The collector of transistor Q7B is connected to resistor R84. The other end of resistor R84 is connected to LDO. The collector of transistor Q7B and resistor R84 are connected to the base. The emitter of transistor Q7B is connected to GND.

[0021] The IN terminal of the charging chip U16 is connected to DOCK_VCC; the nEN terminal of the charging chip U16 is connected to resistor R89, and the other end of resistor R89 ​​is connected to GND; the OUT terminal of the charging chip is connected to capacitor C85 and pin 3 of Q5; the OVLO terminal of the charging chip is connected to resistors R161 and R162, the other end of resistor R161 is connected to GND, and the other end of resistor R162 is connected to DOCK_VCC.

[0022] The beneficial effects of this utility model are: This utility model, at a very low cost, utilizes the switching characteristics of a MOSFET to allow for either USB or the base to be charged separately. It can charge the USB separately or the base separately. When the base and USB are powered at the same time, the base is used first to cut off the USB charging channel, avoid power circulation problems, and ensure the stable operation of the POS machine. Attached Figure Description

[0023] Figure 1 This is a structural diagram of the charging circuit in an embodiment of this utility model;

[0024] Figure 2 This is a flowchart of the charging circuit in an embodiment of this utility model. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0026] like Figure 1 and Figure 2 As shown, this embodiment provides a smart POS machine base and a charging circuit with automatic USB charging switching, including charging chip U15, charging chip U16, MOS parasitic diode Q4, MOS parasitic diode Q5, transistor Q6A, transistor Q6B, transistor Q7A, transistor Q7B, bidirectional Zener diode D14, bidirectional Zener diode D15, capacitor C83, capacitor C84, capacitor C85, resistor R84, resistor R85, resistor R86, resistor R87, resistor R88, resistor R89, resistor R90, resistor R91, resistor R92, resistor R93, resistor R94, resistor R95, resistor R161, resistor R162, resistor R163, and resistor R166;

[0027] The IN terminal of the charging chip U15 is connected to capacitor C84 and VBUS1, and the other end of capacitor C84 is connected to GND; the nEN terminal of the charging chip U15 is connected to one end of resistor R94, and the other end of resistor R94 is connected to GND; a resistor R92 is connected between the nEN terminal of the charging chip U15 and resistor R94, and resistor R92 is connected to DOCK_VCC.

[0028] The OUT terminal of the charging chip U15 is connected to one end of resistor R163. VBUS is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R163 is connected to the base of transistor Q7A. The collector of transistor Q7A is connected to one end of resistor R85. The other end of resistor R85 is connected to LDO. TYPE-C is connected between the collector of transistor Q7A and resistor R85. The emitter of transistor Q7A is grounded. Resistor R166 is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R166 is connected to one end of capacitor C83 and then to GND. The other end of capacitor C83 is connected to DC IN.

[0029] The gate of the MOS parasitic diode Q4 is connected to the collector of the transistor Q6A, and the source of the MOS parasitic diode Q4 is connected to the source of the MOS parasitic diode Q5. The drain of Q4 is connected to the OUT terminal of the charging chip U15. The gate of the MOS parasitic diode Q5 is connected to resistor R88, the other end of resistor R88 is connected to resistor R90, the other end of resistor R90 is connected to the base of transistor Q6A, and the emitter of transistor Q6A is connected to GND.

[0030] A bidirectional Zener diode D14 and a resistor R86 are connected between the gate of the MOS parasitic diode Q4 and the collector of the transistor Q6A. The other end of the bidirectional Zener diode D14 is connected to GND. The other end of the resistor R86 is connected between the MOS parasitic diodes Q4 and Q5. A bidirectional Zener diode D15 is connected between the MOS parasitic diode Q5 and the resistor R88. The other end of the bidirectional Zener diode D15 is connected to GND.

[0031] The DC IN is connected to the source of MOS parasitic diode Q4 and the source of MOS parasitic diode Q5, and then connected to resistor R87. Resistor R87 is connected to resistors R88 and R90, and then connected to the collector of transistor Q6B. The emitter of transistor Q6B is connected to GND. The base of transistor Q6B is connected to resistor R91. The other end of resistor R91 is connected to DOCK_VCC.

[0032] The DOCK_VCC is connected to resistors R95 and R93. The other end of resistor R95 is connected to GND. The other end of resistor R93 is connected to the base of transistor Q7B. The collector of transistor Q7B is connected to resistor R84. The other end of resistor R84 is connected to LDO (…). Figure 1 In the LDO15A_1V8, the collector of the transistor Q7B is connected to the base between the resistor R84 and the emitter of the transistor is connected to GND.

[0033] The IN terminal of the charging chip U16 is connected to DOCK_VCC; the nEN terminal of the charging chip U16 is connected to resistor R89, and the other end of resistor R89 ​​is connected to GND; the OUT terminal of the charging chip is connected to capacitor C85 and pin 3 of Q5; the OVLO terminal of the charging chip is connected to resistors R161 and R162, the other end of resistor R161 is connected to GND, and the other end of resistor R162 is connected to DOCK_VCC.

[0034] In this embodiment, as Figure 1 As shown, the left end is for charging via the USB adapter (i.e., Type-C), and the right end is for charging via the dock. When charging via the USB adapter is used without charging via the dock, U15 is turned on. Utilizing the parasitic diode characteristics of the MOSFET, in conjunction with R86, Q6A, R90, and R87, Q4 is fully turned on, while Q5 is turned off. DC IN powers the device and charges the battery through the charging chip. When only the dock is charging, the parasitic diode characteristics of the MOSFET are again utilized, in conjunction with R91, Q6B, R87, and R88, to fully turn on Q5 and turn off Q4. DC IN powers the device and charges the battery through the charging chip. When both the USB adapter and the dock are powered, the power supply DOCK_VCC turns off the U15 chip via R92 and R94. This sets the dock charging priority to be higher than the USB adapter charging priority.

[0035] In this embodiment, as Figure 1 As shown, U15 and U16 are high-current overvoltage protectors to protect the motherboard during charging. They also shut down the adapter's USB path when the dock and adapter USB are charging simultaneously, prioritizing dock charging. They are active low; when the dock is charging, DOCK_VCC shuts down U15 via R92.

[0036] Q4, R86, Q6A, R90, and R87 work together to utilize the characteristics of the MOS parasitic diode. When the adapter's USB is charging, it is fully turned on, and DC IN is directed to the charging chip to power the device and battery. At this time, Q6A is turned on and Q6B is turned off. The voltage drop across R87 is very small, and Q5 cannot be turned on.

[0037] Q5, R91, Q6B, R87, and R88 work together to utilize the characteristics of the MOS parasitic diode. When the adapter's USB is charging, it is fully turned on, and DC IN is directed to the charging chip to power the device and battery. At this time, Q6B is turned on and Q6A is turned off. The gate and source voltages of Q4 are the same, so Q4 is turned off.

[0038] When entering OTG mode, the charging chip supplies power to DC IN. At this time, there is no voltage at D0CK_VCC, Q6B is off, Q6A is on, the voltage divider of R87 is small, Q5 is off, Q4 is on, and U15 is active low and on, supplying power to the USB. In this embodiment, when VBUS and VBUS1 are used as inputs, the voltages of the corresponding components are shown in Table 1.

[0039] Table 1 Component Voltage

[0040]

[0041] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0042] This invention provides a charging circuit that automatically switches between a smart POS machine base and USB charging. With minimal cost, this invention utilizes the switching characteristics of a MOSFET to allow for either USB charging or base charging. It can charge via USB alone or base alone. When both the base and USB are powered simultaneously, the base is used first, cutting off the USB charging channel and avoiding power circulation problems, thus ensuring the stable operation of the POS machine.

[0043] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A smart POS machine base and a charging circuit with automatic USB charging switching, characterized in that: This includes charging chip U15, charging chip U16, MOS parasitic diode Q4, MOS parasitic diode Q5, transistor Q6A, transistor Q6B, transistor Q7A, transistor Q7B, bidirectional Zener diode D14, bidirectional Zener diode D15, capacitor C83, capacitor C84, capacitor C85, resistor R84, resistor R85, resistor R86, resistor R87, resistor R88, resistor R89, resistor R90, resistor R91, resistor R92, resistor R93, resistor R94, resistor R95, resistor R161, resistor R162, resistor R163, and resistor R166; The IN terminal of the charging chip U15 is connected to capacitor C84 and VBUS1, and the other end of capacitor C84 is connected to GND; the nEN terminal of the charging chip U15 is connected to one end of resistor R94, and the other end of resistor R94 is connected to GND; a resistor R92 is connected between the nEN terminal of the charging chip U15 and resistor R94, and resistor R92 is connected to DOCK_VCC. The OUT terminal of the charging chip U15 is connected to one end of resistor R163. VBUS is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R163 is connected to the base of transistor Q7A. The collector of transistor Q7A is connected to one end of resistor R85. The other end of resistor R85 is connected to LDO. TYPE-C is connected between the collector of transistor Q7A and resistor R85. The emitter of transistor Q7A is grounded. Resistor R166 is connected between the OUT terminal of the charging chip U15 and resistor R163. The other end of resistor R166 is connected to one end of capacitor C83 and then to GND. The other end of capacitor C83 is connected to DCIN. The gate of the MOS parasitic diode Q4 is connected to the collector of the transistor Q6A, and the source of the MOS parasitic diode Q4 is connected to the source of the MOS parasitic diode Q5. The drain of Q4 is connected to the OUT terminal of the charging chip U15. The gate of the MOS parasitic diode Q5 is connected to resistor R88, the other end of resistor R88 is connected to resistor R90, the other end of resistor R90 is connected to the base of transistor Q6A, and the emitter of transistor Q6A is connected to GND. A bidirectional Zener diode D14 and a resistor R86 are connected between the gate of the MOS parasitic diode Q4 and the collector of the transistor Q6A. The other end of the bidirectional Zener diode D14 is connected to GND. The other end of the resistor R86 is connected between the MOS parasitic diodes Q4 and Q5. A bidirectional Zener diode D15 is connected between the MOS parasitic diode Q5 and the resistor R88. The other end of the bidirectional Zener diode D15 is connected to GND. The DCIN is connected to the source of MOS parasitic diode Q4 and the source of MOS parasitic diode Q5, and then connected to resistor R87. Resistor R87 is connected to resistors R88 and R90, and then connected to the collector of transistor Q6B. The emitter of transistor Q6B is connected to GND. The base of transistor Q6B is connected to resistor R91. The other end of resistor R91 is connected to DOCK_VCC. The DOCK_VCC is connected to resistors R95 and R93. The other end of resistor R95 is connected to GND. The other end of resistor R93 is connected to the base of transistor Q7B. The collector of transistor Q7B is connected to resistor R84. The other end of resistor R84 is connected to LDO. The collector of transistor Q7B and resistor R84 are connected to the base. The emitter of transistor Q7B is connected to GND. The IN terminal of the charging chip U16 is connected to DOCK_VCC; the nEN terminal of the charging chip U16 is connected to resistor R89, and the other end of resistor R89 ​​is connected to GND; the OUT terminal of the charging chip is connected to capacitor C85 and pin 3 of Q5; the OVLO terminal of the charging chip is connected to resistors R161 and R162, the other end of resistor R161 is connected to GND, and the other end of resistor R162 is connected to DOCK_VCC.

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