阅读说明：本技术 一种基于mos的用于服务器风扇的电源保护电路 (Power protection circuit for server fan based on MOS ) 是由 任佳琪 于 2021-07-22 设计创作，主要内容包括：本发明公开了一种基于MOS的用于服务器风扇的电源保护电路,包括控制芯片,该控制芯片包括第一NMOS和第二NMOS,第一NMOS具有引脚1、引脚2、引脚3,第二NMOS具有引脚4、引脚5、引脚6；第一供电端P1,所述引脚3连接于该第一供电端P1；第二供电端P2,所述引脚4连接于该第二供电端P2；第一风扇连接端F1,所述引脚2与该第一风扇连接端F1并联；第二风扇连接端F2,所述引脚6连接于该第二风扇连接端F2；第一接地端CND1,所述引脚1连接于该第一接地端CND1；第二接地端CND2,所述引脚3、引脚5共连于该第二接地端CND2,所述引脚4与该第二接地端CND2并联。本发明通过在端口设备上设置保护电路,实现对风扇和端口设备上电保护和故障隔离。(The invention discloses a power protection circuit for a server fan based on an MOS (metal oxide semiconductor), which comprises a control chip, wherein the control chip comprises a first NMOS (N-channel metal oxide semiconductor) and a second NMOS, the first NMOS is provided with a pin 1, a pin 2 and a pin 3, and the second NMOS is provided with a pin 4, a pin 5 and a pin 6; a first power supply terminal P1, the pin 3 being connected to the first power supply terminal P1; a second power supply terminal P2, the pin 4 being connected to the second power supply terminal P2; a first fan connection terminal F1, pin 2 being connected in parallel with the first fan connection terminal F1; a second fan connection end F2, the pin 6 being connected to the second fan connection end F2; a first ground CND1, the pin 1 being connected to the first ground CND 1; and a second ground terminal CND2, the pins 3 and 5 are connected to the second ground terminal CND2 in common, and the pin 4 is connected in parallel to the second ground terminal CND 2. The invention realizes the power-on protection and fault isolation of the fan and the port equipment by arranging the protection circuit on the port equipment.)

1. A power protection circuit for a server fan based on MOS is characterized in that: comprises that

The control chip comprises a first NMOS and a second NMOS, wherein the first NMOS is provided with a pin 1, a pin 2 and a pin 3, and the second NMOS is provided with a pin 4, a pin 5 and a pin 6; the source electrode of the first NMOS is connected with a pin 1, the grid electrode of the first NMOS is connected with a pin 2, and the drain electrode of the first NMOS is connected with a pin 3; the source electrode of the second NMOS is connected with a pin 4, the grid electrode of the second NMOS is connected with a pin 5, and the drain electrode of the second NMOS is connected with a pin 6;

a first power supply terminal P1, the pin 3 being connected to the first power supply terminal P1;

a second power supply terminal P2, the pin 4 being connected to the second power supply terminal P2;

a first fan connection terminal F1, pin 2 being connected in parallel with the first fan connection terminal F1;

a second fan connection end F2, the pin 6 being connected to the second fan connection end F2;

a first ground CND1, the pin 1 being connected to the first ground CND 1;

and a second ground terminal CND2, the pins 3 and 5 are connected to the second ground terminal CND2 in common, and the pin 4 is connected in parallel to the second ground terminal CND 2.

2. The MOS-based power protection circuit for a server fan of claim 1, wherein: the pin 1 is connected in parallel with the first power supply terminal P1 through a resistor R1, a resistor R2 and a capacitor C1.

3. The MOS-based power protection circuit for a server fan of claim 1, wherein: pin 2 is connected via a resistor R3 to the first fan connection F1, and pin 1 is connected in parallel via a capacitor C2 to the first fan connection F1.

4. The MOS-based power protection circuit for a server fan of claim 1, wherein: the pin 3 is connected to a first power supply terminal P1 through a resistor R4.

5. The MOS-based power protection circuit for a server fan of claim 1, wherein: the pins 3 and 5 are connected to the second ground CND2 through a capacitor C3.

6. The MOS-based power protection circuit for a server fan of claim 1, wherein: the pin 4 is connected to the second power supply terminal P2 through a capacitor C4.

7. The MOS-based power protection circuit for a server fan of claim 1, wherein: the pin 6 is connected to the second fan connection terminal F2 via a resistor R5 and is connected in parallel to the second supply terminal P2 via a resistor R6.

8. The MOS-based power protection circuit for a server fan of claim 1, wherein: the voltage of the first power supply terminal P1 is 12V, and the voltage of the second power supply terminal P2 is 3.3V.

Technical Field

The invention belongs to the technical field of circuit protection, and particularly relates to a power supply protection circuit for a server fan based on an MOS.

Background

With the rapid development of domestic internet, the demand for the server is continuously expanded, the processing capacity is stronger and stronger, the power consumption is larger and larger, the heat dissipation becomes the design key, the fan in the heat dissipation system is the key, and the failure of the fan is inevitable in the long-time operation process, so the server puts forward the hot-pluggable requirement on the fan module. Because the space inside the fan is limited, the current fans on the market do not have voltage protection and current protection functions on the power supply input of the fans, and the fan control circuits of various families are different, so that the following problems can occur in the hot plugging process, namely 1, the fans influence the power supply of a host computer to cause shutdown or restart of a system, and the problems are fatal and do not meet the requirements of hot plugging. 2. The system is not halted, but the control circuit of the fan is easily burnt out, causing the failure of the fan.

The following is likely to occur when the fan is running:

1) when the fan is powered on, a short-time large current of a capacitor charging state or the fan breaks down, for example, a power supply circuit of the fan is partially short-circuited to the ground, so that voltage or current is abnormal, the power supply circuit of the port equipment is damaged or closed, and the normal work of a 12V power supply of the server system is influenced.

2) When the port device is abnormal to the power supply VCC of the fan, for example, overvoltage or undervoltage may cause damage to the internal circuit of the fan, and the power chip inside the fan may be burned down in severe cases.

The current scheme for protecting the power supply of the fan is a current-limiting protection technology, which specifically comprises the following steps: a current limiting device is connected in series between a power supply of a fan port and a fan power supply input pin on port equipment, and comprises a special current limiting chip, a fuse, a self-recovery fuse (such as a thermistor (PTC)), and the like. The current limiting protection technique achieves automatic power shut-off of the fan's power supply when the fan itself fails, causing an overcurrent at the plug-in port.

However, the current limiting protection technique has the disadvantage that only partial failure protection of the fan and port equipment is possible. First, protection of the fan and port equipment cannot be provided in the event of a voltage anomaly on the fan power supply channel. The current-limiting protection scheme has the function of performing voltage abnormity protection on the fan and the port equipment under the condition that the fluctuation of the voltage cannot be monitored.

Secondly, the current-limiting protection scheme is based on a current monitoring mode, and has limitations in terms of reaction speed, self-restorability and voltage protection of the protection device. For example, although the fuse can cut off the power supply after an overcurrent fault occurs, the fuse needs a certain heat energy accumulation time for fusing, and cannot rapidly cut off the fault, thereby protecting the fan and the port equipment; and the fuse can not be recovered after being fused, so that the port equipment can be continuously used by a user after being returned to a factory for maintenance. Although the self-recovery fuse can self-recover after the fault is eliminated, the reaction time is slow, the power supply can be cut off only when the time is generally more than tens of ms, the fan and the port equipment are difficult to be protected in time before the protection action, and the fault is not diffused to other places of the equipment. Although the special current-limiting chip has the characteristics of quick protection response time and self-recovery, the current-limiting chip is an active device, the withstand voltage on a pin is low, and the current-limiting chip is connected in series between a power supply and a fan power supply input pin, so that the safety of the current-limiting chip when voltage abnormity occurs on a power supply channel cannot be ensured, and the cost is high.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the MOS-based power protection circuit for the server fan, which can realize power-on protection and fault isolation of the fan and port equipment.

In order to achieve the purpose, the invention adopts the following technical scheme: a power protection circuit for server fan based on MOS includes

The control chip comprises a first NMOS and a second NMOS, wherein the first NMOS is provided with a pin 1, a pin 2 and a pin 3, and the second NMOS is provided with a pin 4, a pin 5 and a pin 6; the source electrode of the first NMOS is connected with a pin 1, the grid electrode of the first NMOS is connected with a pin 2, and the drain electrode of the first NMOS is connected with a pin 3; the source electrode of the second NMOS is connected with a pin 4, the grid electrode of the second NMOS is connected with a pin 5, and the drain electrode of the second NMOS is connected with a pin 6;

a first power supply terminal P1, the pin 3 being connected to the first power supply terminal P1;

a second power supply terminal P2, the pin 4 being connected to the second power supply terminal P2;

a first fan connection terminal F1, pin 2 being connected in parallel with the first fan connection terminal F1;

a second fan connection end F2, the pin 6 being connected to the second fan connection end F2;

a first ground CND1, the pin 1 being connected to the first ground CND 1;

and a second ground terminal CND2, the pins 3 and 5 are connected to the second ground terminal CND2 in common, and the pin 4 is connected in parallel to the second ground terminal CND 2.

Further, the pin 1 is connected in parallel with the first power supply terminal P1 through a resistor R1, a resistor R2 and a capacitor C1.

Furthermore, pin 2 is connected to the first fan connection terminal F1 through a resistor R3, and pin 1 is connected in parallel to the first fan connection terminal F1 through a capacitor C2.

The pin 3 is connected to a first power supply terminal P1 through a resistor R4.

Further, the pins 3 and 5 are connected to the second ground CND2 through a capacitor C3.

Further, the pin 4 is connected to the second power supply terminal P2 through a capacitor C4.

Further, the pin 6 is connected to the second fan connection terminal F2 through a resistor R5, and is connected in parallel to the second power supply terminal P2 through a resistor R6.

Further, the voltage of the first power supply terminal P1 is 12V, and the voltage of the second power supply terminal P2 is 3.3V.

The invention has the following effects:

1) when the power supply voltage provided by the port equipment to the fan is abnormal (overvoltage or undervoltage), the fan can be protected, the fan is prevented from being damaged, and the problem that the conventional scheme has no voltage abnormal protection is solved;

2) when the fan has a fault which causes voltage and current faults on a power supply channel, the fault isolation of the fan can be realized, port equipment and the fan are protected, and the maintenance cost is reduced;

3) the invention has the characteristics of quick protection, self-recovery and high-voltage resistance of the protection device, and can solve the defects of the current-limiting protection scheme;

4) the circuit is simple to realize, has low cost, can completely protect the fan power supply circuit part, and can effectively protect the fan and the server equipment of a user; isolating the fault and preventing the fault expansion from influencing other services of the user; the server manufacturer also avoids the return maintenance of the damaged port equipment caused by the power failure; after the protection is added at the equipment end, the circuit requirement of the fan can be reduced, more suppliers can be selected, and more advantageous cost is obtained;

5) compared with a mode of adding a protection circuit in a fan control circuit, the fan power supply protection circuit reduces the processing cost and processing difficulty of the fan.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Fig. 2 is a schematic diagram of the circuit of the present invention.

Fig. 3 is a schematic diagram of the circuit of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

In the fan module, the fan on-position detection signals are all low and effective, and the fan power supply is obtained from the mainboard. During the hot plug process of the fan module, the situation that the 12V power supply is firstly contacted and GND is not connected easily occurs. At this time, the fan presence detection signal is directly connected to the 12V voltage. The power domain of the signal of the mainboard is generally 3.3V, so an isolation circuit is required to be made in the application of the hot plug.

As shown in fig. 1 to 3, the present invention provides a MOS-based power protection circuit for a server fan, including a control chip, a first power supply terminal P1, a second power supply terminal P2, a first fan connection terminal F1, a second fan connection terminal F2, a first ground terminal CND1, and a second ground terminal CND 2; the control chip adopts a double-NMOS MOSFET device, the VGS withstand voltage of the control chip is 20V, the threshold voltage VGS (TH) is 1V-2.5V, and the application of high-current through-flow is not involved, so that the selected MOSFET has the Id of 200mA at the maximum and is enough to meet the isolation application of a signal line. The selected MOSFET is small in package, and does not occupy a large amount of PCB space; specifically, the control chip comprises a first NMOS and a second NMOS, wherein the first NMOS is provided with a pin 1, a pin 2 and a pin 3, and the second NMOS is provided with a pin 4, a pin 5 and a pin 6; the source electrode of the first NMOS is connected with a pin 1, the grid electrode of the first NMOS is connected with a pin 2, and the drain electrode of the first NMOS is connected with a pin 3; the source of the second NMOS is connected to pin 4, the gate is connected to pin 5, and the drain is connected to pin 6.

Specifically, the pin 3 is connected to a first power supply end P1 through a resistor R4, and the pin 1 is connected in parallel to the first power supply end P1 through a resistor R1, a resistor R2, and a capacitor C1; the pin 4 is connected with a second power supply end P2 through a capacitor C4, and the pin 6 is connected with a second fan connecting end F2 through a resistor R5 and is connected with a second power supply end P2 in parallel through a resistor R6;

the pin 2 is connected to a first fan connection terminal F1 through a resistor R3, the pin 1 is connected to the first ground terminal CND1, and the pin 1 is connected in parallel to the first fan connection terminal F1 through a capacitor C2; the pins 3 and 5 are connected to the second ground terminal CND2 through a capacitor C3, and the pin 4 is connected in parallel to the second ground terminal CND 2.

Preferably, the voltage of the first power supply terminal P1 is 12V, and the voltage of the second power supply terminal P2 is 3.3V. The resistance values of the resistor R1, the resistor R4 and the resistor R6 are 10K, the resistance value of the resistor R2 is 26.7K, the resistance value of the resistor R3 is 1K, and the resistance value of the resistor R5 is 49.9K; the capacitance of the capacitor C1 and the capacitance C4 is 100NF, and the capacitance of the capacitor C2 and the capacitance C3 is 1 NF.

The specific working principle is as follows: when the fan module is not inserted, the voltage of the pin 2 of the first NMOS is about 3.3V by voltage division through the plurality of resistors, in this state, the first NMOS is in an on state, the pin 5 and the pin 3 are grounded through the GND2, the second NMOS is in an off state, and at this time, the signal sent to the motherboard is 3.3V from the top to the rear stage.

When the fan module is plugged in, the signal will be boosted to 12V, at this time, the voltage of pin 2 of the first NMOS is about 12V, the VGS withstand voltage of the first NMOS transistor is 20V, and the current voltage can be endured, so that the first NMOS is kept in an open state, and the whole circuit can bear high-voltage impact under the state.

When the fan module is fully inserted, the level of the signal sent in becomes low level. At the moment, the first NMOS is closed, the voltage of the pin 3 and the pin 5 is increased to 12V, the second NMOSFET is opened, the voltage of the pin 6 is reduced, signal transmission is completed, and safe starting of the fan is achieved.

The invention has the following effects:

1) when the power supply voltage provided by the port equipment to the fan is abnormal (overvoltage or undervoltage), the fan can be protected, and the problem that the conventional scheme has no voltage abnormal protection is solved;

2) when the fan has faults of voltage and current on the power supply channel caused by the faults of the fan, the fault isolation of the fan can be realized, and port equipment and the fan are protected;

3) the invention has the characteristics of quick protection, self-recovery and high-voltage resistance of the protection device, and can solve the defects of the current-limiting protection scheme;

4) the circuit is simple to realize, has low cost, can completely protect the fan power supply circuit part, and can effectively protect the fan and the server equipment of a user; isolating the fault and preventing the fault expansion from influencing other services of the user; the server manufacturer also avoids the return maintenance of the damaged port equipment caused by the power failure; after the protection is added at the equipment end, the circuit requirement of the fan can be reduced, more suppliers can be selected, and more advantageous cost is obtained;

5) compared with a mode of adding a protection circuit in a fan control circuit, the circuit for protecting the power supply of the fan is arranged on the port equipment, so that the processing cost and the processing difficulty of the fan are reduced

The embodiments described above do not limit the scope of protection of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution. The invention herein may be practiced in the absence of any element or elements, limitation or limitations, which limitation or limitations is not specifically disclosed herein. The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described, but it is recognized that various modifications and changes may be made within the scope of the invention and the claims which follow. It is to be understood that the embodiments described herein are examples and features of some embodiments and that modifications and variations may be made by one of ordinary skill in the art in light of the teachings of this disclosure, and are to be considered within the purview of this disclosure and scope of the appended claims and their equivalents.