CN118226941A - Quick power-down device and method for sub-board - Google Patents

Abstract

The invention relates to the technical field of quick power-down of a daughter board, in particular to a quick power-down device and a quick power-down method of the daughter board, wherein the power-down device comprises: the main board DCDC converter is used for converting direct-current voltage on the main board into core voltage; the optocoupler is used for isolating the core voltage so as to control an enable signal (EN) of one DCDC converter on the daughter board; a daughter board DCDC converter for converting an input voltage into a secondary voltage; when the power supply of the product is cut off, the output of the main board DCDC converter stops to cause the core voltage to be rapidly reduced to 0, and the optocoupler is turned off, so that the enable signal (EN) of the sub board DCDC converter becomes zero, and the rapid synchronous shutdown of the sub board and the main board is realized; the invention ensures stable and independent operation of the small system and realizes power-off synchronization among different systems by the uniquely designed quick power-off device of the daughter board, thereby ensuring compatibility between the daughter board system and the main board and smoothness of communication.

Description

Quick power-down device and method for sub-board

Technical Field

The invention relates to the technical field of quick power-down of a daughter board, in particular to a quick power-down device and method of the daughter board.

Background

The product dc voltage input to the tape deck is derived from the motherboard or product power supply, and typically is directly supplied from the motherboard to the daughter board through the connector after the voltage is converted using DCDC. However, for products with relatively high motherboard and daughter board independence, voltage inputs of different sources can maintain minimum system stability, such as switch motherboard failure but daughter POE boards continue to power external powered products. If the direct-current high-voltage input of the daughter board is powered down for too long, the daughter board is not restarted and initialized when being powered up again quickly, and communication errors between the daughter board and the main board can possibly occur to cause product faults.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides a device and a method for quickly powering down a sub-board so as to solve the technical problem of long power-down time of direct-current high-voltage input of a product sub-board of the sub-board.

The technical scheme for solving the technical problems is as follows:

Providing a quick power-down device for a seed plate, wherein the power-down device comprises:

the main board DCDC converter is used for converting direct-current voltage on the main board into core voltage;

The optocoupler is used for isolating the core voltage so as to control an enable signal (EN) of one DCDC converter on the daughter board;

a daughter board DCDC converter for converting an input voltage into a secondary voltage;

When the power supply of the product is cut off, the output of the main board DCDC converter is stopped to cause the core voltage to be rapidly reduced to 0, and the optocoupler is turned off, so that the enable signal (EN) of the sub board DCDC converter becomes zero, and the rapid synchronous shutdown of the sub board and the main board is realized.

Still further, the optocoupler has at least one input pin for receiving the core voltage from the motherboard DCDC converter and at least one output pin for outputting an enable signal to the daughter board DCDC converter.

Furthermore, when the direct current input voltage of the daughter board is overlarge, the voltage dividing device is arranged to reduce the direct current input voltage of the daughter board and then input the reduced direct current input voltage to the input pin of the optocoupler device.

Still further, the optocoupler output pin is connected to the start-up pin (PU 4 EN) of the daughter board DCDC converter, so that the daughter board DCDC converter is started up when the voltage on the output pin exceeds a certain threshold.

Further, the daughter board DCDC converter outputs a secondary voltage for normal operation of the product upon receiving an enable signal (EN).

Furthermore, when the main board is powered off, the secondary core voltage of the main board becomes 0, the output of the optocoupler is 0, the starting pin (PU 4 EN) of the daughter board DCDC converter does not receive the starting signal, the output is 0, and the daughter board system stops working.

Further, there is provided a method for rapidly powering down a daughter board, using a daughter board rapid powering down apparatus as described above, the method comprising the steps of:

S100, obtaining core voltage and isolating through an optical coupler device when a product works normally through a DCDC converter on a main board;

S200, using a photo-coupler device, and controlling an enabling signal of the DCDC converter on the sub-board according to the state of the DCDC converter on the main board;

s300, when a power supply of a product is powered off, reducing the core voltage output by a DCDC converter of a main board to zero;

s400, closing the optocoupler device to enable the DCDC converter of the daughter board to lose the enabling signal, and realizing quick shutdown of the daughter board.

Still further, it includes using a voltage divider device to reduce the daughter board dc input voltage to an acceptable level for the optocoupler device when it is too large.

Furthermore, the output end of the enabling signal (EN) is connected with the starting pin (PU 4 EN) of the DCDC converter of the daughter board, and a voltage threshold value is set on the starting pin (PU 4 EN) for determining the starting or stopping working state of the DCDC converter.

The beneficial effects of the invention are as follows:

The invention ensures stable and independent operation of the small system and realizes power-off synchronization among different systems by the uniquely designed quick power-off device of the daughter board, thereby ensuring compatibility between the daughter board system and the main board and smoothness of communication.

In addition, the invention also provides a method for quickly powering down the sub-board, which allows the sub-board system to independently and safely operate under the condition of not being influenced by an external unstable power supply through intelligent interaction of an enabling signal and the DCDC converter, and simultaneously ensures that the sub-board can carry out instant communication and synchronous action with the main board when the product needs to be quickly powered down, thereby effectively avoiding communication faults caused by uninitialization of the factor board system.

In the power-off process, the invention effectively avoids abnormal communication between the daughter board and the main board caused by transient voltage instability, which is realized by providing a stable enabling signal and setting a reasonable voltage threshold value, ensures that the DCDC converter is started and stopped under a proper voltage condition, further controls the power-down and the starting of the daughter board, and in addition, the addition of the voltage dividing equipment further enhances the toughness of the system in the face of voltage fluctuation, protects the optocoupler from being damaged by excessive high voltage, and simultaneously ensures the accurate transmission of a power-down instruction.

The invention has the beneficial effects that the stability of the system is greatly improved, which is particularly important for electronic products requiring high reliability and long-term stable operation, in addition, the invention provides a more flexible solution for power management, so that a product developer can more easily realize the optimal design of the electronic system.

Drawings

FIG. 1 is a block diagram of a fast power down sub-panel device of the present invention;

FIG. 2 is a circuit diagram of a design of the quick power-down device of the sub-board of the present invention;

FIG. 3 is a flow chart of the method for quickly powering down the sub-panel of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. Examples of the embodiments are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements throughout or elements having like or similar functionality. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the present invention.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically connected, electrically connected or can be communicated with each other; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

The following disclosure provides many different embodiments, or examples, for implementing different structures of the invention. In order to simplify the present disclosure, components and arrangements of specific examples are described below. They are, of course, merely examples and are not intended to limit the invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, which are for the purpose of brevity and clarity, and which do not themselves indicate the relationship between the various embodiments and/or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art will recognize applications of other processes and/or usage scenarios for other materials.

In order to facilitate understanding of the technical scheme of the present invention, first, the working principle of the present invention is briefly described:

As shown in fig. 1, when the product works normally, the main board obtains a core voltage through DCDC conversion, the core voltage realizes control of the sub board EN through optocoupler isolation, the secondary voltage of the sub board is converted from the sub board DCDC, when the product is powered off, the direct current input of the main board stops, the secondary core voltage of the main board drops to 0 rapidly, the optocoupler is turned off, the DCDC EN input of the sub board is 0, the secondary core voltage of the sub board is 0, and the sub board and the main board can realize actions such as rapid synchronous shutdown and startup configuration management.

As shown in fig. 2, the specific circuit of the daughter board mainly works as follows: when the input and output of the power supply of the product are normal and the voltage of the secondary core of the main board is normal, the optocoupler is conducted; if the direct current input voltage of the daughter board is overlarge, the voltage is required to be divided and then the voltage is input into 4 pins of the optocoupler; the output voltage of the 3-pin of the optocoupler exceeds the threshold value of the DCDC PU4 EN of the daughter board, the DCDC starts to normally output the secondary voltage of the daughter board, and the product works normally.

When the power supply of the product stops inputting, the direct-current low-voltage input of the main board is 0, the secondary core voltage of the main board is 0, and the optocoupler is turned off, so that the 3-pin output of the optocoupler is 0; the high-voltage input of the daughter board is slow to power down, the input voltage of the DCDC EN of the daughter board is 0, the output is 0, and the system of the daughter board is shut down to stop working.

Referring to fig. 1 to 3, the present invention provides the following preferred embodiments:

Example 1

The embodiment describes in detail a system for realizing rapid power-down of a daughter board in a product for a tape board and independent power input, which is mainly composed of three components: a main board dc-dc converter (main board DCDC converter), an optocoupler device and another dc-dc converter on a daughter board (daughter board DCDC converter), the main board DCDC converter functions to obtain a dc voltage from the main board and convert it into a core voltage, and then the core voltage plays a control role on an enable signal (EN) of the daughter board DCDC converter through the isolation role of the optocoupler device.

Further, when the power supply of the product is normally supplied, the DCDC converter of the daughter board normally operates by means of the enable signal received from the optocoupler device to convert the input voltage thereof into the secondary voltage for the daughter board, and it is to be understood that this secondary voltage is necessary for the normal operation of the daughter board.

It can be understood that the quick power-down device described in this embodiment can ensure that the daughter board can obtain appropriate control signals under different operation conditions by properly selecting the optocoupler device and (if needed) the voltage dividing resistor, and through the system and the method described in this embodiment, the user can realize stable independent operation of the product subsystem and synchronous operation of power supply shutdown between different systems, thereby improving the robustness of the product in the face of sudden power-off situations and effectively avoiding product faults generated in the quick power-off and starting processes.

Example two

According to the foregoing embodiment of the present invention, the application of an optocoupler device is provided for implementing a fast power-down function of a daughter board, where the optocoupler device has at least one input pin and at least one output pin, the input pin is configured to receive a core voltage from a main board DCDC converter, and the output pin is configured to transmit an enable signal converted from the core voltage to the daughter board DCDC converter.

Further, when the system is in a normal working state, the main board DCDC converter provides a stable core voltage to an input pin of the optocoupler, then the optocoupler performs an electrical signal isolation process, and sends an isolated signal to an enable pin of the sub board DCDC converter, so that the isolated signal can be started and provide necessary secondary voltage to the sub board, and it is understood that when the main board DCDC converter stops working due to power failure, the core voltage is rapidly reduced to 0, and the output pin of the optocoupler is correspondingly closed, so that an enable signal of the sub board DCDC converter is set to 0, thereby rapidly realizing the power-down of the sub board.

It can be understood that by reasonably designing and selecting the optocoupler device and the pin configuration thereof, accurate control of the power-down speed of the daughter board can be realized, and the daughter board can be ensured to be rapidly and safely turned off in synchronization with the power-down of the main board or the product power supply. The technology not only improves the stability and reliability of the whole product, but also can effectively avoid the problem of abnormal communication between the daughter board and the main board caused by quick power failure.

Through the technical scheme of the embodiment, for the product systems with the tape boards and needing independent power input, the stability and independence of the system can be realized, the secondary system is synchronously closed after the power supply is cut off, and the dynamic management of the system is optimized, so that the product can be quickly and safely restarted after the power supply is cut off, the product faults caused by abnormal communication are greatly reduced, and the stability of the whole system and the use experience of users are improved.

Example III

According to the rapid power-down device for a daughter board and the configuration of the input/output pins of the optocoupler device of the rapid power-down device described in the foregoing embodiments, the present embodiment further provides a solution in which, in the case of an excessive dc input voltage of the daughter board, voltage dividing equipment is used to reduce the input voltage and then the reduced dc input voltage is transmitted to the input pins of the optocoupler device.

Further, the voltage dividing device in this embodiment is designed between the sub-board and the optocoupler device, so as to ensure that the dc input voltage of the sub-board is within a range meeting the requirements of the optocoupler device, when the dc input voltage of the sub-board is higher than the allowed input voltage threshold of the optocoupler device, the voltage is reduced appropriately by the voltage dividing device, and then the reduced value is input to the input pin of the optocoupler device, so as to ensure that the optocoupler device can operate at a safe voltage level, avoid damage caused by overvoltage, and ensure that the sub-board can operate stably at different working voltages.

It will be appreciated that by designing the voltage divider circuit with appropriate resistance values, the dc inputs for different voltage levels can be effectively controlled. Therefore, the input voltage level of the optocoupler device is guaranteed to meet the requirement, the enabling signal of the output pin is guaranteed to be accurate, and the normal operation of the DCDC converter of the daughter board is further maintained.

It can be understood that by reasonably selecting the voltage dividing equipment and adjusting the voltage dividing proportion, the effective conversion of the input signal under high voltage can be ensured, so that the stability of the starting of the DCDC of the daughter board is ensured, the voltage dividing device and the optocoupler device provided by the embodiment are combined for application, the function of quickly powering down the daughter board is realized, the normal starting and running of the system under different voltage input conditions are ensured, the flexibility and the adaptability of the product are improved, the fault phenomenon caused by voltage fluctuation can be effectively avoided, and the robustness of the whole product is enhanced.

Example IV

According to the use of the daughter board quick power down apparatus and the voltage dividing device described in the foregoing embodiments, the present embodiment describes in detail the application of the optocoupler device in the daughter board quick power down apparatus, in this embodiment, the output pin of the optocoupler device is connected to the start pin (PU 4 EN) of the daughter board DCDC converter, and the purpose of the connection configuration is that the daughter board DCDC converter will be started when the voltage on the output pin of the optocoupler device exceeds a set specific threshold.

Further, the optocoupler plays a key role, and as an isolation component, it ensures electrical signal isolation between the main board and the daughter board, and reduces mutual electrical interference, it is to be understood that the voltage of the output pin of the optocoupler must be precisely controlled, so as to ensure that the DCDC converter of the daughter board can be reliably started when a preset starting threshold is exceeded, and when the product is in a normal power input/output state, the secondary core voltage provided by the main board is conducted to the pin PU4 EN of the DCDC converter of the daughter board through the optocoupler, the DCDC converter of the daughter board is started, and the system of the daughter board can work normally.

It can be understood that under the condition of power failure of the product, the direct current low-voltage input of the main board is stopped, the secondary core voltage is rapidly reduced to 0, the optocoupler device is correspondingly turned off, the output pin voltage of the optocoupler is reduced to 0 at the moment, and the EN pin of the DCDC converter of the sub-board is not activated in the state because the high-voltage input of the sub-board is slowly powered down, so that the DCDC of the sub-board does not generate output, the sub-board system stops working, and the rapid synchronous shutdown with the main board is realized.

By the technical scheme provided by the embodiment, even after the product is rapidly powered off, the sub-board system can be rapidly closed when necessary and is ready for initialization when powered on, so that the problem of product failure caused by abnormal communication with the main board is avoided, the stability and reliability of the product are further enhanced, and the application of the technical scheme ensures that the independent operation of the product subsystem and simultaneously realizes rapid and effective synchronous power-off at the system level.

Example five

The present embodiment provides a scheme for starting up and outputting a secondary voltage of a daughter board DCDC converter under a specific condition, in this embodiment, the daughter board DCDC converter is designed to perform an action of outputting the secondary voltage when receiving an enable signal (EN) thereof, so that a product works normally, thereby optimizing power management of the product and guaranteeing stability of power input and output.

Further, the enable signal (EN) of the daughter board DCDC converter is controlled by an optocoupler device, which isolates the nuclear power voltage obtained by DCDC conversion of the main board and then controls the start of the daughter board DCDC converter, and it is understood that such a design not only optimizes power management and improves the independence between the daughter board and the main board, but also enhances the stability and reliability of the product in the face of a fast power failure or an abnormal voltage state.

When the power input and output of the product are normal and the nuclear power voltage of the main board is stable, the optocoupler is conducted, the voltage dividing equipment ensures that the DC input voltage of the daughter board is input into the pin 4 of the optocoupler after being proper, so that the output voltage of the pin 3 of the optocoupler exceeds a specific threshold value, the DCDC converter of the daughter board is started, and then the DCDC converter of the daughter board outputs stable secondary voltage, so that the normal operation of the product is ensured.

The daughter board DCDC converter is used as a core output component and plays an extremely important role in maintaining the stable power supply output of a product, and provides necessary energy for the electrical components of the daughter board by maintaining proper power supply, so that the daughter board DCDC converter can work stably and efficiently.

Example six

According to the design principle and the working mode of the daughter board quick power-down device described in the foregoing, this embodiment relates to how to realize the quick stop of the daughter board system through the interaction between the optocoupler and the daughter board DCDC converter under the condition of power failure of the motherboard, when the motherboard is powered down, the secondary core voltage of the motherboard becomes 0, at this time, the status of the motherboard is fed back to the daughter board through the optocoupler, the output of the optocoupler is 0, and the start pin (PU 4 EN) of the daughter board DCDC converter does not receive a start signal.

Further, since the start pin does not receive a signal, the DCDC converter of the daughter board does not output a corresponding secondary voltage, so that the circuit of the daughter board loses the electric energy required for operation, thereby causing the system of the daughter board to stop operating rapidly.

Under the normal operating condition of the product, the daughter board DCDC converter can receive an effective starting signal from the optocoupler device and output stable secondary voltage for the daughter board system to use, so that the normal operation of the product is ensured.

Through this embodiment, product designer can make a reliable and effectual solution to manage the power state of subplate, and the guarantee product can realize the quick response of subplate when taking place the outage, avoids latent product trouble, and this kind of design has not only strengthened the mutual independence between the product subsystem, has also ensured the overall stability and the security of product when power state is unusual simultaneously to market competition and the user satisfaction of product have been promoted.

Example seven

According to the rapid power-down device for the daughter board described in the foregoing embodiment, the present embodiment provides a method for achieving rapid power-down of the daughter board by using the device, where the method obtains a core voltage through a DCDC converter on a motherboard when a product works normally, and then uses an optocoupler to implement isolation, so as to ensure safe and independent operation of a daughter board system.

Further, by utilizing the isolation characteristic of the optocoupler, the enable signal (EN) of the daughter board DCDC converter is controlled according to the state output of the motherboard DCDC converter, and it is to be understood that the optocoupler plays a role in signal transmission, and safely transmits the operation state of the motherboard to the daughter board.

When the power supply of the product is powered off, the method turns off the output signal of the optical coupler device by ensuring that the core voltage output by the DCDC converter of the main board is reduced to zero, and it is understood that the turn-off of the output signal of the optical coupler device leads to the start pin of the DCDC converter of the sub board to lose the enabling signal, so that the quick shutdown of the sub board is realized, and the process is rapidly carried out when the power failure occurs, thereby effectively avoiding the possible damage to the sub board system.

According to the technical scheme, through the steps, the power management and protection measures of the neutron board are designed to realize quick and safe power failure, and the transmission and interruption of the enabling signals are accurately controlled, so that the whole power control link is simplified, the response speed and reliability of the system are increased, excellent protection measures and stable operation experience can be provided for users in modern high-requirement electronic products, the technical scheme has very important application value, the technical scheme is not only provided, and a solid foundation is provided for the safety of products and the reliability of the users.

Example eight

According to the method for quickly powering down the daughter board in the foregoing embodiment, in order to cope with the abnormal rise of the dc input voltage of the daughter board, a measure is provided to prevent the optocoupler from being damaged due to the excessive voltage.

Further, it can be understood that the introduction of the voltage dividing device not only effectively protects the optocoupler device from damage caused by overhigh input voltage, but also ensures that the optocoupler device can stably operate at a safe voltage level without being influenced by voltage fluctuation. By accurately controlling the voltage value input to the optocoupler, the voltage dividing device ensures the voltage stability of the whole system and is beneficial to improving the overall reliability and safety of the system.

The method can effectively limit potential negative influence on the rapid power-down system of the daughter board due to unexpected high-voltage events, and can optimize the performance of the whole rapid power-down system by reasonably selecting parameters of the voltage dividing equipment to adapt to different working environments and voltage conditions, so that the application range and reliability of the rapid power-down method of the daughter board are greatly improved and the adaptability of the product to unstable power supply environments is enhanced by carefully designing and implementing the voltage dividing protection scheme.

Example nine

According to the foregoing description of the rapid power-down method for the daughter board, in this embodiment, in order to ensure that the DCDC converter of the daughter board can start or stop working under appropriate conditions, a connection manner between the output end of the enable signal (EN) and the start pin (PU 4 EN) of the DCDC converter of the daughter board is further disclosed, and in addition, a voltage threshold is set on the start pin, where the voltage threshold is used to explicitly determine the working state of the DCDC converter.

Further, it can be understood that the design enables the start and stop of the DCDC converter of the daughter board to be performed according to a stable and accurate voltage threshold, so as to ensure that the power management and protection measures of the daughter board can be more accurate and effective.

The setting of the voltage threshold value not only provides a simple and reliable way to control the working state of the daughter board DCDC converter, but also reduces the potential risk caused by misoperation or abnormal state.

The foregoing description of the preferred embodiments of the invention is not intended to limit the invention, but rather to enable any modification, equivalent replacement, improvement or the like to be made within the spirit and principles of the invention.

Claims (9)

1. The utility model provides a quick power-down device of seed board, its characterized in that, power-down device includes:

the main board DCDC converter is used for converting direct-current voltage on the main board into core voltage;

The optocoupler is used for isolating the core voltage so as to control an enable signal (EN) of one DCDC converter on the daughter board;

a daughter board DCDC converter for converting an input voltage into a secondary voltage;

When the power supply of the product is cut off, the output of the main board DCDC converter is stopped to cause the core voltage to be rapidly reduced to 0, and the optocoupler is turned off, so that the enable signal (EN) of the sub board DCDC converter becomes zero, and the rapid synchronous shutdown of the sub board and the main board is realized.

2. The daughter board rapid power down apparatus of claim 1, wherein the optocoupler has at least one input pin for receiving a core voltage from the motherboard DCDC converter and at least one output pin for outputting an enable signal to the daughter board DCDC converter.

3. The rapid power-down apparatus for a daughter board as claimed in claim 2, wherein a voltage dividing device is provided to reduce the dc input voltage of the daughter board and then input the reduced dc input voltage to the input pin of the optocoupler device when the dc input voltage of the daughter board is excessively high.

4. A daughter board quick power down device as claimed in claim 3, wherein the optocoupler output pin is connected to the start pin (PU 4 EN) of the daughter board DCDC converter to start the daughter board DCDC converter when the voltage on the output pin exceeds a certain threshold.

5. The daughter board rapid power down apparatus of claim 4, wherein the daughter board DCDC converter outputs a secondary voltage for normal product operation upon receiving an enable signal (EN).

6. The rapid power-down apparatus of claim 5, wherein when the main board is powered off, the main board secondary core voltage becomes 0, the optocoupler output is 0, the start pin (PU 4 EN) of the DCDC converter of the sub board does not receive the start signal, the output is 0, and the sub board system is stopped.

7. A method for quickly powering down a daughter board using a device for quickly powering down a daughter board according to any of claims 1 to 6, said method comprising the steps of:

through a DCDC converter on the main board, when the product works normally, core voltage is obtained and isolated through an optocoupler;

using a optocoupler to control an enable signal of the DCDC converter on the daughter board according to a state of the main board DCDC converter;

When the power supply of the product is powered off, reducing the core voltage output by the DCDC converter of the main board to zero;

and the optocoupler device is turned off, so that the DCDC converter of the daughter board loses an enabling signal, and the quick shutdown of the daughter board is realized.

8. The method of claim 7, including using a voltage divider device to reduce the dc input voltage of the daughter board to an acceptable level when it is too high.

9. A method for fast power down of a daughter board according to claim 8, characterized in that the enable signal (EN) output is connected to a start-up pin (PU 4 EN) of the daughter board DCDC converter and a voltage threshold is set on the start-up pin (PU 4 EN) for determining the start-up or stop operating state of the DCDC converter.