Docking station circuit and device with stable output voltage
By introducing a combination of power modules, voltage conversion modules, energy storage units, and protection units into the expansion dock, the problem of voltage instability during power switching of the expansion dock is solved, stable voltage output is achieved, equipment malfunctions are prevented, and user experience is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN CE LINK LTD
- Filing Date
- 2024-12-31
- Publication Date
- 2026-07-21
AI Technical Summary
During power switching of the expansion dock, when the external power supply is unplugged, the expansion dock and peripherals cannot be powered normally, resulting in a drop in voltage. This causes the Buck-Boost circuit to lock up due to undervoltage, affecting the function of the equipment.
It adopts a combination of power supply module, voltage conversion module, energy storage unit and protection unit. The energy storage unit provides stable voltage output during power switching, and the protection unit prevents the voltage conversion module from undervoltage lockout.
Ensure the docking station maintains a stable voltage output during power switching to prevent device shutdown and improve user experience.
Smart Images
Figure CN224537845U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of docking stations, and more particularly to a docking station circuit and device with a stable output voltage. Background Technology
[0002] A docking station is a hardware device used to connect portable devices (such as laptops) to multiple external devices (such as monitors, keyboards, mice, storage devices, etc.) to expand their functionality. Through interfaces such as USB and Type-C, docking stations can provide higher data transfer rates, video output, and power supply, and support features such as multi-monitor output, network connectivity, and external storage devices.
[0003] Because the Type-C interface supports power delivery, video transmission, and USB 3.2 data transfer simultaneously, an external Type-C docking station is required to achieve this. When using a Type-C docking station, an external power source can charge the laptop through the dock's Type-C port. At this time, other peripherals are also connected to the dock, and the external power source supplies power to these peripherals. If the external power source is unplugged, the laptop starts supplying power to the docking station and peripherals. However, there is a power supply transition time during power switching, typically 150µs. Since the docking station's internal resistors consume power, and its USB ports need to supply power, the voltage output from the USB port may not reach the minimum rated voltage. This can cause peripherals to malfunction for a short period, or even lead to a shutdown and restart. Therefore, a capacitor is usually added to the docking station's circuitry to store energy and supply voltage to the docking station and peripherals during power switching, ensuring the peripherals connected to the dock continue to function properly.
[0004] The problem is that during the power switching period (FRS), the external power supply is unplugged and cannot power the docking station and peripherals, while the laptop's power supply has not yet been sent out. This power supply is typically 5V, but the load on the docking station's 5V main circuit continues to consume power, causing the energy storage capacitor to deplete and the voltage to drop. To maintain the 5V output, the docking station's internal power circuit draws current from the docking station's power interface. However, because the laptop and external power supply do not provide sufficient power, if the load is heavy, the voltage in the power circuit will continue to drop due to the large current drawn. When the voltage drops below the undervoltage protection voltage of the Buck-Boost (inside the docking station) (usually between 2.5 and 4V), the Buck-Boost circuit will lock out the output for several milliseconds. During this undervoltage lockout period, the docking station will be unusable, causing malfunctions and severely impacting the user experience. Utility Model Content
[0005] To address the technical deficiencies mentioned in the background section, this application provides a docking station circuit with a stable output voltage, which effectively solves the problem of devices connected to the docking station failing to function properly when the external power supply is switched.
[0006] The present invention adopts the following technical solution: In a first aspect, this application provides a docking station circuit with a stable output voltage, including a power module, a voltage conversion module, an energy storage unit, and a protection unit. The power module has a first voltage input terminal, a second voltage input terminal, and a first voltage output terminal. The first voltage input terminal is electrically connected to a first external power source, and the second voltage input terminal is electrically connected to a second external power source. The power module is used to receive voltage supplied by the first or second external power source. The voltage conversion module has a third voltage input terminal and a second voltage output terminal. The third voltage input terminal is electrically connected to the first voltage output terminal. The voltage conversion module is used to convert the voltage supplied by the power module into a voltage output terminal. The voltage is regulated and supplied to external devices; the input terminal of the energy storage unit is electrically connected to the voltage conversion module, and the output terminal of the energy storage unit is grounded. The energy storage unit is used to supply the operating voltage required by the external devices during the switching from the first external power supply to the second external power supply; a protection unit is connected in series between the voltage conversion module and the energy storage unit. The protection unit is used to supply the voltage output by the energy storage unit to the voltage conversion module when the voltage at the second voltage input terminal is lower than the voltage at the second voltage output terminal during the switching from the first external power supply to the second external power supply, so as to maintain the rated voltage of the voltage conversion module supplied to the external devices.
[0007] Optionally, the protection unit includes: A first current-limiting resistor, the first end of which is electrically connected to the second voltage output terminal and the second end of which is electrically connected to the energy storage unit, is used to limit the current when the voltage conversion module charges the energy storage unit. A first diode, the anode of which is electrically connected to the output terminal of the energy storage unit and the cathode of which is electrically connected to the third voltage input terminal, is used to conduct and supply the voltage of the energy storage unit to the third voltage input terminal when the first external power supply is switched to the second external power supply and the voltage supplied at the second voltage input port is less than the voltage required by the external device.
[0008] Optionally, the protection unit further includes: The second current-limiting resistor has its first end electrically connected to the third voltage input terminal and its second end electrically connected to the energy storage unit. The second diode has its cathode electrically connected to the second voltage output terminal and its anode electrically connected to the energy storage unit.
[0009] Optionally, both the first diode and the second diode are Schottky diodes.
[0010] Optionally, the energy storage unit includes an electrolytic capacitor, the positive terminal of which is electrically connected to the anode of the first diode, and the negative terminal of which is grounded.
[0011] Optionally, the voltage conversion module includes The first filter unit has one end electrically connected to the first voltage output terminal and the other end grounded. A voltage conversion chip, wherein the voltage conversion chip is electrically connected to the first filter unit; An inductor, wherein a first end of the inductor is electrically connected to the voltage conversion chip, and a second end is electrically connected to an external device; The second filter unit has one end electrically connected to the second end of the inductor and the other end grounded.
[0012] Optionally, the first filtering unit includes at least one first filtering capacitor, one end of which is electrically connected to the first voltage output terminal and the other end is grounded.
[0013] The second filtering unit includes at least one second filtering capacitor, one end of which is electrically connected to the second end of the inductor, and the other end is grounded.
[0014] Optionally, the voltage conversion module further includes: The first NMOS transistor has its drain electrically connected to the output terminal of the first filter unit, its source electrically connected to the first terminal of the inductor, and its gate electrically connected to the voltage conversion chip. The drain of the second NMOS transistor is electrically connected to the input terminal of the second filter unit, the source of the second NMOS transistor is electrically connected to the second terminal of the inductor, and the gate is electrically connected to the voltage conversion chip.
[0015] Optionally, the voltage conversion module further includes at least one USB port, at least two Type-C interfaces, and at least one HDMI interface, wherein the at least two Type-C interfaces are electrically connected to the first voltage input port and the second voltage input port in sequence.
[0016] Secondly, this application also provides a docking station device with a stable output voltage, including the docking station circuit with a stable output voltage as described above; An outer casing having an internal space; The circuit board, on which the expansion dock circuit with a stable output voltage is etched, is disposed within the housing. In summary, the beneficial effects of this utility model are as follows: By setting up a power module, the voltages of the first and second external power supplies can be connected. The voltage conversion module adjusts the voltage supplied by the power module to meet the voltage requirements of the external devices. During the switching between the first and second external power supplies, the energy storage unit can supply the corresponding voltage to the external devices to prevent power outages or malfunctions during the switching process. The protection unit then guides the voltage from the energy storage unit to the voltage conversion module to prevent insufficient voltage from the power module. This allows the voltage conversion module to supply a portion of the electrical energy to the voltage conversion module, enabling the second voltage output terminal of the voltage conversion module to supply the rated voltage to the external devices and preventing the voltage conversion module from entering an undervoltage lockout state due to insufficient voltage. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is an architectural diagram of an embodiment of the present utility model; Figure 2 This is a schematic diagram of an embodiment of the present utility model; Figure 3 This is another schematic diagram of an embodiment of the present utility model; Figure 4 This is a schematic diagram of the power supply module according to an embodiment of the present utility model; Figure 5 This is a schematic diagram of the voltage conversion module according to an embodiment of the present invention. Attached image description: 100. Power supply module; V1, first voltage input terminal; V2, second voltage input terminal; C1, first capacitor; Q1, first PMOS transistor; R1, first resistor; R2, second resistor; Q3, third NMOS transistor; R3, third resistor; C2, second capacitor; Q2, second PMOS transistor; R4, fourth resistor; R5, fifth resistor; Q4, fourth NMOS transistor; R6, sixth resistor; R7, seventh resistor; R8, eighth resistor; 200, Voltage conversion module; V3, Third voltage input terminal; V4, Second voltage output terminal; Q5, First NMOS transistor; Q6, Second NMOS transistor; 210, First filter unit; 220, Second filter unit; L1, Inductor; U1, Voltage conversion chip; 300, Energy storage unit; EC1, Electrolytic capacitor; 400, Protection unit; RD1, First current-limiting resistor; RD2, Second current-limiting resistor; D1, First diode; D2, Second diode. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0021] like Figure 1As shown, this utility model embodiment provides a docking station circuit with a stable output voltage, including a power module 100, a voltage conversion module 200, an energy storage unit 300, and a protection unit 400. The power module 100 has a first voltage input terminal V1, a second voltage input terminal V2, and a first voltage output terminal. The first voltage input terminal V1 is electrically connected to a first external power source, and the second voltage input terminal V2 is electrically connected to a second external power source. The power module 100 is used to receive voltage supplied by the first or second external power source. A third voltage input terminal V3 is electrically connected to the first voltage output terminal. The voltage conversion module 200 is used to adjust the voltage supplied by the power module 100 and supply it to external devices. Energy storage... The input terminal of unit 300 is electrically connected to the voltage conversion module 200, and the output terminal of the energy storage unit 300 is grounded. The energy storage unit 300 is used to supply the operating voltage required by the external device during the switching from the first external power supply to the second external power supply. The protection unit 400 is connected in series between the voltage conversion module 200 and the energy storage unit 300. The protection unit 400 is used to supply the voltage output by the energy storage unit 300 to the voltage conversion module 200 when the voltage of the second voltage input terminal V2 is lower than the voltage of the second voltage output terminal V4 during the switching from the first external power supply to the second external power supply, so as to maintain the rated voltage of the voltage conversion module 200 supplied to the external device.
[0022] In this embodiment, the first voltage input terminal V1 of the power module 100 can be connected to an external power source, such as a charger or a charging power supply. The second voltage input terminal V2 can be connected to a laptop or an electronic device with a Type-C interface. Furthermore, this embodiment can have two or more Type-C interfaces. Therefore, this application can not only charge or communicate with the device connected to it through the voltage supplied by the first voltage input terminal V1, but also charge the electronic device connected to it through the voltage supplied by the second voltage input terminal V2. Furthermore, the power module 100 may include a first capacitor C1, a first PMOS transistor Q1, a first resistor R1, a second resistor R2, a third NMOS transistor Q3, a third resistor R3, a second capacitor C2, a second PMOS transistor Q2, a fourth resistor R4, a fifth resistor R5, a fourth NMOS transistor Q4, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8. The first terminal of the first capacitor C1 is electrically connected to the first voltage input terminal V1, and the second terminal is grounded. The drain of the first PMOS transistor Q1 is electrically connected to the first voltage input terminal V1, the source is electrically connected to the first terminal of the seventh resistor R7, and the gate is electrically connected to the first terminal of the first resistor R1. The first terminal of the second resistor R2 is electrically connected to the second terminal of the first resistor R1. The drain of the third NMOS transistor Q3 is electrically connected to the second terminal of the second resistor R2, and the gate is electrically connected to the control terminal of an external circuit. The source of the third NMOS transistor Q3 is grounded. The first terminal of the third resistor R3 is electrically connected to the first control terminal and the third NMOS transistor of the external circuit. Between the OS transistors Q3 and the third resistor R3, the other end of the third resistor R3 is grounded; the first end of the second capacitor C2 is electrically connected to the second voltage input terminal V2, and the second end is grounded; the drain of the second PMOS transistor Q2 is electrically connected to the second voltage input terminal V2; the source of the second PMOS transistor Q2 is electrically connected to the first end of the eighth resistor R8; the gate of the second PMOS transistor Q2 is electrically connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is electrically connected to the first end of the fifth resistor R5; the second end of the fifth resistor R5 is electrically connected to the drain of the fourth NMOS transistor Q4; the gate of the fourth NMOS transistor Q4 is electrically connected to the second control terminal of the external circuit; the source of the fourth NMOS transistor Q4 is grounded; the first end of the seventh resistor R7 is electrically connected to the source of the first PMOS transistor Q1; the second end of the seventh resistor R7 is electrically connected to the first end of the second resistor R2; the first end of the eighth resistor R8 is electrically connected to the source of the second PMOS transistor Q2; and the second end of the eighth resistor R8 is electrically connected to the first end of the fifth resistor R5. By configuring the power module 100 described above, after the first external power supply is disconnected, a second external power supply can be switched to power this application and the electronic devices connected to this application.
[0023] Furthermore, such as Figure 5As shown, the voltage conversion module 200 can have a third voltage input terminal V3 and a second voltage output terminal V4. The third voltage input terminal V3 is electrically connected to the first voltage output terminal, and the second voltage output terminal V4 is connected to an external device. Specifically, it can be connected to the VBUS pin (power pin) of a USB interface. The voltage conversion module 200 adjusts the voltage provided by the power module 100 to a voltage level suitable for the external device and ensures a stable voltage output. Since the voltage supplied by external power supplies and electronic devices such as laptops cannot meet the power needs of many external devices, the voltage conversion module 200 can be used to adjust the voltage accordingly and then output the corresponding voltage through the second voltage output terminal V4, thereby providing power to the external devices.
[0024] Furthermore, such as Figure 3 As shown, the energy storage unit 300 has a positive terminal and a negative terminal (the positive terminal is the input terminal, and the negative terminal is the output terminal). The positive terminal is electrically connected to the second voltage output terminal V4, and the negative terminal is grounded. By configuring the energy storage unit 300, the external devices connected to this application will not experience a brief power outage during the switch from the first external power supply to the second external power supply, thus ensuring the normal operation of the external devices. However, during the switch from the first external power supply to the second external power supply, if the external load is large, it will absorb current from the energy storage unit 300. At the same time, the components in the voltage conversion module 200 will also consume some electrical energy. Therefore, in order to maintain the 5V output, the voltage conversion module 200 will absorb current from the second external power supply. However, if the second external power supply does not provide sufficient voltage support, the voltage in the voltage conversion module 200 will drop, even below the preset voltage (which can be 5V). This will cause the voltage conversion module 200 to perform undervoltage protection, thereby shutting down the output for several milliseconds. Therefore, the external devices connected to this application will have no voltage supply during these few milliseconds, causing the external devices to shut down, which seriously affects the user experience. Therefore, by setting up the protection unit 400, when the first external power supply switches to the second external power supply and the voltage at the second voltage input terminal V2 is lower than the voltage at the second voltage output terminal V4, the protection unit 400 causes the voltage output by the energy storage unit 300 to be supplied to the voltage conversion module 200, so as to maintain the rated voltage of the voltage conversion module 200 supplied to the external device. In other words, the energy storage unit 300 supplies a portion of the current to the voltage conversion module 200, thereby enabling the voltage conversion module 200 to provide a portion of the voltage when dealing with a large external load, preventing the voltage conversion module 200 from entering the undervoltage protection state, and thus preventing the external device from shutting down due to insufficient voltage, improving the user experience.
[0025] Optional, such as Figure 2 As shown, the protection unit 400 includes a first current-limiting resistor RD1 and a first diode D1. The first end of the first current-limiting resistor RD1 is electrically connected to the second voltage output terminal V4, and the second end is electrically connected to the energy storage unit 300. The first current-limiting resistor RD1 is used to limit the current when the voltage conversion module 200 charges the energy storage unit 300. The anode of the first diode D1 is electrically connected to the output terminal of the energy storage unit 300, and the cathode is electrically connected to the third voltage input terminal V3. The first diode D1 is used to conduct and supply the voltage of the energy storage unit 300 to the third voltage input terminal V3 when the first external power supply is switched to the second external power supply and the voltage supplied by the second voltage input terminal V2 is less than the voltage required by the external device.
[0026] In this embodiment, the first terminal of the first current-limiting resistor RD1 is electrically connected to the second voltage output terminal V4 of the voltage conversion module 200, the second terminal of the first current-limiting resistor RD1 is electrically connected to the positive terminal of the energy storage unit 300, the anode of the first diode D1 is electrically connected to the second terminal of the first current-limiting resistor RD1 and the positive terminal of the energy storage capacitor, and the cathode of the first diode D1 is electrically connected to the third voltage input terminal V3 of the voltage conversion module 200. By setting the first current-limiting resistor RD1, the energy storage unit 300 can be current-limited when the first external power supply or the second external power supply provides voltage input, thereby providing power to the energy storage unit 300. By setting the first diode D1, during the switching between the first external power supply and the second external power supply, the first diode D1 can split the voltage in the energy storage unit 300 to the voltage conversion module 200, preventing the voltage conversion module 200 from over-discharge and entering an undervoltage state, maintaining the second voltage output terminal V4 of the voltage conversion module 200 at a normal 5V output, thereby providing the required power to external devices.
[0027] Optional, such as Figure 2 As shown, the protection unit 400 may further include a second current-limiting resistor RD2 and a second diode D2. The first end of the second current-limiting resistor RD2 is electrically connected to the third voltage input terminal V3, and the second end of the second current-limiting resistor RD2 is electrically connected to the energy storage unit 300. The cathode of the second diode D2 is electrically connected to the second voltage output terminal V4, and the anode of the second diode D2 is electrically connected to the energy storage unit 300.
[0028] In this embodiment, the first terminal of the second current-limiting resistor RD2 is electrically connected to the third voltage input terminal V3, and the second terminal is electrically connected to the input terminal of the energy storage unit 300. The anode of the second diode D2 is electrically connected to the energy storage unit 300, and the cathode is electrically connected to the third voltage output terminal. By setting the second current-limiting resistor RD2 and the second diode D2, it is possible to prevent the external device from being overloaded. Specifically, when the first external power supply or external device is subjected to an excessive load, the first current-limiting resistor RD1 and the second current-limiting resistor RD2 can prevent the external device from being overloaded. The first diode D1 and the second diode D2 can be low-dropout Schottky diodes, and the resistance values of the first current-limiting resistor RD1 and the second current-limiting resistor RD2 can be between 100R and 100KΩ, thereby ensuring that the voltage on the positive terminal of the energy storage unit 300 is maintained between 5.3V and 6V.
[0029] Optionally, the energy storage unit 300 may include an electrolytic capacitor EC1, which has a positive terminal and a negative terminal. The positive terminal of the electrolytic capacitor EC1 is electrically connected to the anode of the first diode D1, and the negative terminal of the electrolytic capacitor EC1 is grounded.
[0030] Optional, such as Figure 5 As shown, the voltage conversion module 200 includes a first filter unit 210, an inductor L1, and a second filter unit 220. One end of the first filter unit 210 is electrically connected to the first voltage output terminal, and the other end is grounded. A voltage conversion chip U1 is electrically connected to the first filter unit 210. The first end of the inductor L1 is electrically connected to the voltage conversion chip U1, and the second end is electrically connected to an external device. One end of the second filter unit 220 is electrically connected to the second end of the inductor L1, and the other end is grounded.
[0031] Optionally, the voltage conversion module 200 further includes a first NMOS transistor Q5 and a second NMOS transistor Q6. The drain of the first NMOS transistor Q5 is electrically connected to the output terminal of the first filter unit 210, the source of the first NMOS transistor Q5 is electrically connected to the first terminal of the inductor L1, and the gate is electrically connected to the voltage conversion chip U1. The drain of the second NMOS transistor Q6 is electrically connected to the input terminal of the second filter unit 220, the source of the second NMOS transistor Q6 is electrically connected to the second terminal of the inductor L1, and the gate is electrically connected to the voltage conversion chip U1.
[0032] In this embodiment, one end of the first filter unit 210 is electrically connected to the first voltage output terminal, and the other end is grounded. Simultaneously, the voltage of the first voltage output terminal is transmitted to pin 20 of the voltage conversion chip U1 through one end of the first filter unit 210. At the same time, the drain of the first NMOS transistor Q5 is also electrically connected to one end of the first filter unit 210, the source of the first NMOS transistor Q5 is electrically connected to the first end of the inductor L1, and the gate of the first NMOS transistor Q5 is electrically connected to pin 18 of the voltage conversion chip U1. The source of the second NMOS transistor Q6 is electrically connected to the second end of the inductor L1, the gate is electrically connected to pin 9 of the voltage conversion chip U1, and the drain of the second NMOS transistor Q6 is electrically connected to pin 7 of the voltage conversion chip U1. One end of the second filter unit 220 is electrically connected to the drain of the second NMOS transistor Q6. By setting the first filter unit 210 to filter the voltage of the third voltage input terminal V3, and the second filter unit 220 to filter the output voltage of the second terminal of the inductor L1, the voltage supplied to the electrolytic capacitor EC1 and the protection unit 400 can be filtered and smoothed.
[0033] Optionally, the voltage conversion module 200 further includes at least one USB port, at least two Type-C interfaces and at least one HDMI interface, wherein the at least two Type-C interfaces are electrically connected in sequence to the first voltage input terminal V1 and the second voltage input terminal V2.
[0034] In this embodiment, the USB port is used to connect external devices, such as a mouse or keyboard. There are two Type-C interfaces: the first is the port electrically connected to the first voltage input terminal V1, and the second is the port connected to the second voltage input terminal V2. The first voltage input terminal V1 is usually connected to an external power supply, and the second voltage input terminal V2 is usually connected to a laptop or other electronic devices with a Type-C interface. The HDMI interface is used to connect an audio display device.
[0035] The second aspect of this application discloses a docking station device (not shown in the figure) with a stable output voltage, comprising the docking station circuit with a stable output voltage as described above, a housing, and a circuit board, the housing having an internal space; the docking station circuit with a stable output voltage is etched onto the circuit board, and the circuit board is disposed within the housing. By configuring the above-described electronic device, it is possible to prevent untimely voltage delivery during the switching between a first external power supply and a second external power supply, thus preventing external devices connected to the docking station from shutting down or causing other functional failures.
[0036] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0037] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A docking station circuit with a stable output voltage, characterized in that, include: A power module has a first voltage input terminal, a second voltage input terminal, and a first voltage output terminal. The first voltage input terminal is electrically connected to a first external power source, and the second voltage input terminal is electrically connected to a second external power source. The power module is used to receive voltage supplied by the first external power source or the second external power source. A voltage conversion module has a third voltage input terminal and a second voltage output terminal. The third voltage input terminal is electrically connected to the first voltage output terminal. The voltage conversion module is used to adjust the voltage supplied by the power module and supply it to external devices. An energy storage unit, the input terminal of which is electrically connected to the voltage conversion module, and the output terminal of which is grounded, is used to supply the operating voltage required by the external device during the switching from the first external power supply to the second external power supply; A protection unit is connected in series between the voltage conversion module and the energy storage unit. The protection unit is used to ensure that when the first external power supply is switched to the second external power supply and the voltage at the second voltage input terminal is lower than the voltage at the second voltage output terminal, the protection unit sends the voltage output by the energy storage unit to the voltage conversion module to maintain the rated voltage of the voltage conversion module when it is sent to the external device.
2. The expansion dock circuit with stable output voltage as described in claim 1, characterized in that... The protection unit includes: A first current-limiting resistor, the first end of which is electrically connected to the second voltage output terminal and the second end of which is electrically connected to the energy storage unit, is used to limit the current when the voltage conversion module charges the energy storage unit. A first diode, the anode of which is electrically connected to the output terminal of the energy storage unit and the cathode of which is electrically connected to the third voltage input terminal, is used to conduct and supply the voltage of the energy storage unit to the third voltage input terminal when the first external power supply is switched to the second external power supply and the voltage supplied at the second voltage input terminal is less than the voltage required by the external device.
3. The expansion dock circuit with stable output voltage as described in claim 2, characterized in that, The protection unit also includes: The second current-limiting resistor has its first end electrically connected to the third voltage input terminal and its second end electrically connected to the energy storage unit. The second diode has its cathode electrically connected to the second voltage output terminal and its anode electrically connected to the energy storage unit.
4. The expansion dock circuit with stable output voltage as described in claim 3, characterized in that... Both the first diode and the second diode are Schottky diodes.
5. The expansion dock circuit with stable output voltage as described in claim 2, characterized in that, The energy storage unit includes an electrolytic capacitor, the positive terminal of which is electrically connected to the anode of the first diode, and the negative terminal of which is grounded.
6. The expansion dock circuit with stable output voltage as described in claim 1, characterized in that, The voltage conversion module includes: The first filter unit has one end electrically connected to the first voltage output terminal and the other end grounded. A voltage conversion chip, wherein the voltage conversion chip is electrically connected to the first filter unit; An inductor, wherein a first end of the inductor is electrically connected to the voltage conversion chip, and a second end is electrically connected to an external device; The second filter unit has one end electrically connected to the second end of the inductor and the other end grounded.
7. The expansion dock circuit with stable output voltage as described in claim 6, characterized in that, The first filtering unit includes at least one first filtering capacitor, one end of which is electrically connected to the first voltage output terminal and the other end is grounded; The second filtering unit includes at least one second filtering capacitor, one end of which is electrically connected to the second end of the inductor, and the other end is grounded.
8. The expansion dock circuit with stable output voltage as described in claim 7, characterized in that, The voltage conversion module also includes: The first NMOS transistor has its drain electrically connected to the output terminal of the first filter unit, its source electrically connected to the first terminal of the inductor, and its gate electrically connected to the voltage conversion chip. The drain of the second NMOS transistor is electrically connected to the input terminal of the second filter unit, the source of the second NMOS transistor is electrically connected to the second terminal of the inductor, and the gate is electrically connected to the voltage conversion chip.
9. The expansion dock circuit with stable output voltage as described in claim 1, characterized in that, The voltage conversion module further includes at least one USB port, at least two Type-C interfaces and at least one HDMI interface, wherein the at least two Type-C interfaces are electrically connected to the first voltage input terminal and the second voltage input terminal in sequence.
10. A docking station device with a stable output voltage, characterized in that, Includes the docking station circuit with a stable output voltage as described in any one of claims 1-9; An outer casing having an internal space; The circuit board, wherein the expansion dock circuit with a stable output voltage is etched on the circuit board, is disposed within the housing.