POE_PD-based power supply maintenance circuit structure and electronic device

Abstract

The utility model discloses a kind of power supply maintaining circuit structure and electronic equipment based on POE_PD, including POE PD module, dummy load branch, control branch and MCU or CPU module.Dummy load branch is composed of resistance R1 and transistor Q1, control branch is constituted by transistor Q2 and relevant resistance, and the working state of dummy load is dynamically switched by PWR_ON signal.When PWR_ON is pulled low, dummy load access circuit provides at least 10mA current, ensures POE system online;When PWR_ON is pulled high, dummy load stops working to reduce power consumption.It can solve the problem of POE system offline caused by light load under soft switch-off state, while taking into account the power consumption optimization during normal operation, suitable for various POE power supply products.

Description

Technical Field

[0001] This utility model relates to the field of electronic equipment technology, and more specifically, to a power supply maintenance circuit structure and electronic equipment based on POE_PD. Background Technology

[0002] In the field of electronics, PoE (Power over Ethernet) has been widely adopted due to its convenience and efficiency. Currently, many electronic devices require the ability to power on instantly and are equipped with soft switching to meet user operational needs. Soft switching is a special switching control method in electronic systems, its core characteristic being that the switching operation does not physically disconnect the power supply, but rather allows the system to switch between "running" and "low-power standby" states. However, implementing this function in PoE power supply systems presents technical challenges.

[0003] Specifically, when the soft switch is in the off state, the electronic system enters a "low-power standby" state. This causes the current detected by the PoE power supply equipment (PSE) to be lower than the 10mA threshold required to maintain power supply, thus determining that the powered device (PD) has entered an offline state. Once in the offline state, the PoE PSE will stop continuously supplying power and instead periodically re-detect the PD signal and briefly supply power to the system to detect whether the PD has reconnected. However, this brief power supply may mislead the system into thinking it has been "re-energized," triggering the "automatic power-on" function, which in turn causes the electronic system to restart automatically, failing to achieve the function of maintaining the "low-power standby" state that the soft switch should perform.

[0004] Existing technologies attempt to address this problem through various means, but often face challenges such as circuit complexity, difficulty in optimizing power consumption, and insufficient system stability. Therefore, there is an urgent need for a technical solution that can maintain PoE power supply while optimizing power consumption, in order to overcome the shortcomings of traditional technologies and ensure the overall performance of the system. Utility Model Content

[0005] To address this issue, this invention provides a power supply maintenance circuit structure and electronic device based on POE_PD, thereby solving the technical problem in the prior art where the soft switch of a POE power supply system has poor stability in maintaining a "low-power standby" state due to insufficient current when the soft switch is in the off state.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A power supply sustaining circuit structure based on POE_PD includes:

[0008] PoE PD module, with power output terminal;

[0009] The dummy load branch is electrically connected at one end to the power supply output terminal of the POE PD.

[0010] One end of the control branch is electrically connected to the power supply output terminal of the POE PD;

[0011] The control processing module has its power input terminal electrically connected to the power output terminal of the POE PD module, and the control pin of the control processing module is electrically connected to the PWR_ON control signal terminal.

[0012] The PWR_ON control signal terminal is electrically connected to the other end of the dummy load branch and the other end of the control branch, respectively. When the PWR_ON control signal terminal switches to a low level, the dummy load branch is turned on and the control branch is turned off. When the PWR_ON control signal terminal switches to a high level, the control branch is turned on and the dummy load branch is turned off.

[0013] Based on the above technical solution, the present invention is further described as follows:

[0014] As a further embodiment of this utility model,

[0015] The dummy load branch includes resistor R1 and transistor Q1;

[0016] The control branch includes transistor Q2, resistor R2, and resistor R3;

[0017] The power supply output terminal of the POE PD module is connected to one end of the resistor R1, one end of the resistor R2, and the power supply input terminal of the control processing module, respectively.

[0018] The other end of the resistor R1 is connected to the collector of the transistor Q1, and the base of the transistor Q1 is connected to the collector of the transistor Q2 and its emitter is grounded.

[0019] The base of transistor Q2 is connected to the PWR_ON control signal terminal through resistor R3, the emitter is grounded and the collector is connected to the other end of resistor R2 and the base of transistor Q1.

[0020] As a further embodiment of this utility model,

[0021] The control processing module is set as an MCU or CPU module, which is used to control the level state of the PWR_ON control signal terminal to realize the switching between normal system operation and soft shutdown state.

[0022] As a further embodiment of this utility model,

[0023] When the PWR_ON control signal is high, transistor Q2 is turned on and transistor Q1 is turned off. The power supply output of the POE PD module directly supplies power to the MCU or CPU module, and resistor R1 is not connected to the circuit.

[0024] As a further embodiment of this utility model,

[0025] When the PWR_ON control signal terminal is low, transistor Q2 is turned off, transistor Q1 is turned on, and resistor R1 is connected to the circuit, forming a current loop from the power supply output terminal of the POE PD module through resistor R1 and transistor Q1 to ground.

[0026] As a further embodiment of this utility model,

[0027] The control branch also includes resistor R4;

[0028] The PWR_ON control signal terminal is also grounded through the resistor R4 and connected to the control pin of the MCU or CPU module.

[0029] As a further embodiment of this utility model,

[0030] The resistance value of the resistor R1 is configured such that the current generated when it is turned on is not less than 10mA.

[0031] As a further embodiment of this utility model,

[0032] The transistor Q1 is configured as a PNP type;

[0033] The transistor Q2 is configured as an NPN type.

[0034] As a further embodiment of this utility model,

[0035] The maximum collector-emitter voltage of transistor Q1 is higher than the supply voltage of the POE PD module, and the conduction characteristic of transistor Q1 is fully turned on when transistor Q2 is turned off;

[0036] The maximum collector-emitter voltage of transistor Q2 is higher than the supply voltage of the POE PD module, and the conduction characteristic of transistor Q2 is fully turned on when transistor Q1 is turned off;

[0037] The resistance value of resistor R2 is configured such that when transistor Q2 is turned on, the collector voltage of resistor R2 drops to near ground potential.

[0038] An electronic device includes the aforementioned POE_PD-based power supply sustaining circuit structure.

[0039] This utility model has the following beneficial effects:

[0040] This circuit structure, by introducing a collaborative working mechanism between the dummy load branch and the control branch, provides a power supply sustaining circuit that can both solve the light-load problem of PoE systems and reduce power consumption during normal system operation. This solution not only meets the practical needs of PoE power supply products but also achieves efficient functional expansion through a simple design, providing important technical support for related fields. Attached Figure Description

[0041] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The structures, proportions, sizes, etc., drawn in this specification are only used to complement the content disclosed in the specification, so that those skilled in the art can understand and read them. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0042] Figure 1 A schematic circuit block diagram of the power supply maintenance circuit structure based on POE_PD provided for an embodiment of this utility model.

[0043] The attached diagram lists the components represented by each number as follows:

[0044] PoE PD module - Power over Ethernet (POE) powered device;

[0045] MCU or CPU module - microcontroller or central processing unit;

[0046] Resistor R1; Transistor Q1 (PNP type); Resistor R2; Transistor Q2 (NPN type); Resistor R3; PWR_ON control signal terminal; Resistor R4. Detailed Implementation

[0047] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0048] The terms "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this utility model. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of implementation of this utility model.

[0049] like Figure 1 As shown, this utility model embodiment provides a power supply sustaining circuit structure based on POE_PD and an electronic device including the above-mentioned power supply sustaining circuit structure. The core of this power supply sustaining circuit structure lies in achieving stable support for the POE power supply system by introducing a dummy load branch and a control branch, while taking into account soft switching function and power consumption optimization. The following is in conjunction with the appendix. Figure 1 The specific implementation methods are described in detail.

[0050] Figure 1 This is a block diagram of the power supply maintenance circuit of this utility model. The PoE PD module is a Power over Ethernet (PoE) receiving device used to convert PoE power into a stable operating voltage required by the system. The MCU or CPU module is a microcontroller or central processing unit. The core power supply maintenance circuit is located between the PoE PD module and the MCU or CPU module, including a dummy load branch and a control branch. The dummy load branch consists of resistor R1 and transistor Q1, while the control branch consists of transistor Q2, resistors R2, R3, and R4. The entire circuit switches states via the PWR_ON control signal terminal, thereby achieving a soft-switching function.

[0051] Specifically, the power output terminal PWR of the PoE PD module is connected to one end of resistor R1, one end of resistor R2, and the power input terminal of the MCU or CPU module. The other end of resistor R1 is connected to the collector (pin 3) of transistor Q1. The base (pin 1) of transistor Q1 is connected to the collector (pin 3) of transistor Q2 via a circuit, and the emitter (pin 2) is directly grounded. The base (pin 1) of transistor Q2 is connected to the PWR_ON control signal terminal through resistor R3, the emitter (pin 2) is grounded, and the collector (pin 3) is connected to the other end of resistor R2 and the base (pin 1) of transistor Q1. The PWR_ON control signal terminal is also grounded through resistor R4 and connected to the corresponding control pin of the MCU or CPU module. This connection allows the circuit to dynamically adjust the dummy load operating mode according to the state of the PWR_ON signal, providing reliable technical support for the soft-switching function of the PoE power supply system.

[0052] When the system is powered off, and the PWR_ON control signal is pulled low, the current flowing into the base (pin 1) of transistor Q2 is cut off, and transistor Q2 is turned off. After transistor Q2 is turned off, its collector (pin 3) potential is pulled high by the PWR voltage output from the POE PD module through resistor R3. Because the collector (pin 3) voltage of transistor Q2 increases, the base (pin 1) voltage of transistor Q1 also increases. For PNP transistor Q1, when its emitter (pin 2) voltage is higher than its base (pin 1) voltage, and the voltage difference between the emitter (pin 2) and base (pin 1) meets the conduction condition (VEB≥0.7V), transistor Q1 turns on. At this time, resistor R1 is connected to the circuit, forming a dummy load. The presence of the dummy load resistor R1 keeps the output current of the POE PD module above 10mA, meeting the POE_PSE's minimum holding current detection requirement, thus preventing the system from entering an offline state. In this state, even if the electronic function implementation system is in light load mode, the POE_PSE device can still detect sufficient current to avoid entering offline state, which solves the problem of POE power supply interruption due to insufficient current when the traditional soft switch is turned off, and ensures that the soft switch function can be implemented stably.

[0053] When the system needs to be powered on, the PWR_ON control signal is pulled high. At this time, current flows through resistor R2 to the base (pin 1) of transistor Q2. Since transistor Q2 is an NPN transistor, the voltage difference between its base (pin 1) and emitter (pin 2) meets the conduction condition (VBE≥0.7V), and transistor Q2 turns on. After transistor Q2 turns on, its collector (pin 3) potential is pulled low to near ground potential. Since transistor Q1 is a PNP transistor, its base (pin 1) is connected to the collector (pin 3) of transistor Q2. At this time, the voltage at the base (pin 1) of transistor Q1 decreases, and the voltage difference between its emitter (pin 2) and base (pin 1) does not meet the conduction condition (VEB<0.7), causing transistor Q1 to turn off. At this time, the PWR voltage output by the POE PD module directly powers the MCU or CPU module through the line. The output current of the POE PD module only needs to meet the requirements of normal system operation, without having to maintain the dummy load power consumption. With the dummy load resistor R1 not connected to the circuit, the system is in normal operating condition. The POE_PSE device can detect the system's load current and maintain a stable power supply. This design reduces the overall power consumption of the system while maintaining the soft-switching off function, thus improving the efficiency of power resource utilization.

[0054] The design of the dummy load branch must meet the requirements of precise current control. Taking resistor R1 as an example, its resistance value needs to be calculated based on the POE supply voltage and the required holding current.

[0055] Assuming a PoE supply voltage of 48V and a required sustaining current of 10mA, the resistance of resistor R1 is calculated to be 4.8kΩ. Furthermore, the maximum collector-emitter (pin 3) voltage across transistor Q1 is higher than the supply voltage of the PoE PD module, and its conduction characteristic is fully open when transistor Q2 is off. For example, a PNP transistor of type 2N3906 can be selected, but is not limited to, with a maximum collector-emitter (pin 3) voltage across 40V, which can meet the needs of most PoE applications.

[0056] Resistors R2 and R3 in the control branch serve as voltage divider and current limiter, respectively. Their resistance values ​​are selected based on the base (pin 1) drive current requirements of transistor Q2 and the voltage range of the PWR_ON signal.

[0057] Specifically, assuming the PWR_ON signal is at a logic level of 3.3V and the base (pin 1) drive current of transistor Q2 is 1mA, the resistance of resistor R3 can be calculated to be 3.3kΩ. The resistance of resistor R2 ensures that when transistor Q2 is turned on, its collector (pin 3) voltage can quickly drop to near ground potential; therefore, the resistance of resistor R2 is chosen to be 1kΩ. Resistor R4 acts as a pull-down resistor, ensuring that transistor Q2 is in a default off state when the PWR_ON signal is not explicitly assigned a value, thus avoiding false triggering. Therefore, the resistance of resistor R4 is chosen to be 10kΩ to balance the pull-down effect and power consumption, ensuring the overall architectural stability.

[0058] This invention has a wide range of practical applications, especially suitable for PoE power-enabled products that are sensitive to power consumption and require soft-switching control. For example, in IP cameras, users may want the device to automatically turn on or off after receiving a network command without physical operation. Traditional soft-switching designs may cause the PoE system to repeatedly restart in the off state, affecting the user experience. With the power supply maintenance circuit of this invention, the dummy load branch maintains the online state of the PoE system in the off state, while automatically shutting down the dummy load in the on state, thus achieving stable soft-switching function and significantly reducing system power consumption.

[0059] To further verify the feasibility of this invention, actual testing can be conducted. The test environment includes a PoE switch, a development board equipped with the circuitry of this invention, and an oscilloscope. The test steps are as follows: First, connect the development board to the PoE switch, observe the current waveform on the oscilloscope, and record the output current of the PoE system. Second, send a PWR_ON signal through the MCU or CPU module to test the current changes in the power-off and power-on states. Finally, compare the power consumption data when the dummy load is connected and disconnected to verify the performance of this invention under different operating modes.

[0060] Test results show that when the PWR_ON signal is low, the dummy load resistor R1 is successfully connected to the circuit, and the output current of the PoE system stabilizes above 10mA, meeting the minimum holding current requirement of PoE_PSE. At this time, the PoE system remains online, without any offline or restarting issues. When the PWR_ON signal is high, the dummy load resistor R1 automatically disconnects from the circuit, and the output current of the PoE system drops to the level required for normal system operation, significantly reducing power consumption. This effectively solves the light-load problem of the PoE system and optimizes power consumption.

[0061] In summary, this invention provides a power supply sustaining circuit that addresses the light-load problem in PoE systems while reducing power consumption during normal system operation by introducing a collaborative working mechanism between the dummy load branch and the control branch. This solution not only meets the practical needs of PoE power supply products but also achieves efficient functional expansion through a simple design, providing important technical support for related fields.

[0062] Although the present invention has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A power supply sustaining circuit structure based on POE_PD, characterized in that, include: PoE PD module, with power output terminal; The dummy load branch is electrically connected at one end to the power supply output terminal of the POE PD. One end of the control branch is electrically connected to the power supply output terminal of the POE PD; The control processing module has its power input terminal electrically connected to the power output terminal of the POE PD module, and the control pin of the control processing module is electrically connected to the PWR_ON control signal terminal. The PWR_ON control signal terminal is electrically connected to the other end of the dummy load branch and the other end of the control branch, respectively. When the PWR_ON control signal terminal switches to a low level, the dummy load branch is turned on and the control branch is turned off. When the PWR_ON control signal terminal switches to a high level, the control branch is turned on and the dummy load branch is turned off.

2. The power supply sustainment circuit structure based on POE_PD according to claim 1, characterized in that, The dummy load branch includes resistor R1 and transistor Q1; The control branch includes transistor Q2, resistor R2, and resistor R3; The power supply output terminal of the POE PD module is connected to one end of the resistor R1, one end of the resistor R2, and the power supply input terminal of the control processing module, respectively. The other end of the resistor R1 is connected to the collector of the transistor Q1, and the base of the transistor Q1 is connected to the collector of the transistor Q2 and its emitter is grounded. The base of transistor Q2 is connected to the PWR_ON control signal terminal through resistor R3, the emitter is grounded and the collector is connected to the other end of resistor R2 and the base of transistor Q1.

3. The power supply sustaining circuit structure based on POE_PD according to claim 2, characterized in that, The control processing module is set as an MCU or CPU module, which is used to control the level state of the PWR_ON control signal terminal to realize the switching between normal system operation and soft shutdown state.

4. The power supply sustaining circuit structure based on POE_PD according to claim 3, characterized in that, When the PWR_ON control signal is high, transistor Q2 is turned on and transistor Q1 is turned off. The power supply output of the POE PD module directly supplies power to the MCU or CPU module, and resistor R1 is not connected to the circuit.

5. The power supply sustaining circuit structure based on POE_PD according to claim 4, characterized in that, When the PWR_ON control signal terminal is low, transistor Q2 is turned off, transistor Q1 is turned on, and resistor R1 is connected to the circuit, forming a current loop from the power supply output terminal of the POE PD module through resistor R1 and transistor Q1 to ground.

6. The power supply sustaining circuit structure based on POE_PD according to claim 3, characterized in that, The control branch also includes resistor R4; The PWR_ON control signal terminal is also grounded through the resistor R4 and connected to the control pin of the MCU or CPU module.

7. The power supply sustaining circuit structure based on POE_PD according to claim 2, characterized in that, The resistance value of the resistor R1 is configured such that the current generated when it is turned on is not less than 10mA.

8. The power supply sustaining circuit structure based on POE_PD according to claim 2, characterized in that, The transistor Q1 is configured as a PNP type; The transistor Q2 is configured as an NPN type.

9. The power supply sustaining circuit structure based on POE_PD according to claim 2, characterized in that, The maximum collector-emitter voltage of transistor Q1 is higher than the supply voltage of the POE PD module, and the conduction characteristic of transistor Q1 is fully turned on when transistor Q2 is turned off; The maximum collector-emitter voltage of transistor Q2 is higher than the supply voltage of the POE PD module, and the conduction characteristic of transistor Q2 is fully turned on when transistor Q1 is turned off; The resistance value of resistor R2 is configured such that when transistor Q2 is turned on, the collector voltage of resistor R2 drops to near ground potential.

10. An electronic device, characterized in that, Includes the power supply sustaining circuit structure based on POE_PD as described in any one of claims 1-9.

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