CN117707317A - Mainboard and computing equipment - Google Patents

Abstract

The application discloses a motherboard and a computing device; the main board comprises: the device comprises a controller, a slow start switch, a charging circuit and a slow start capacitor; the charging circuit comprises a switch module and a charging resistor; the first end of the slow start switch is electrically connected with the power supply unit and the first end of the switch module; the second end of the switch module is electrically connected with the first end of the charging resistor; the second end of the slow start switch is electrically connected with the second end of the charging resistor; the slow start control signal output end of the controller is electrically connected with the control end of the slow start switch; the charging control signal output end of the controller is electrically connected with the control end of the switch module; the controller is used for controlling the switch module to be conducted according to a preset duty ratio, so that the power supply unit charges the slow start capacitor according to the preset duty ratio through the charging resistor; the preset duty ratio is determined according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor. The requirement of slow start circuit component selection can be reduced, the cost is reduced, and the power supply efficiency is improved.

Description

Mainboard and computing equipment

Technical Field

The embodiment of the application relates to the technical field of servers, in particular to a mainboard and computing equipment.

Background

The computing device includes a motherboard and a power supply unit that supplies power to a load on the motherboard. When the load is hot plugged, larger current is generated, and impact is caused to the power supply unit; therefore, a slow start circuit is usually designed between the power supply unit and the load.

The slow start circuit generally comprises a hot plug controller, a current detection resistor and a Metal-Oxide-Semiconductor (MOS) field effect transistor, wherein the hot plug controller is used for detecting voltages at two ends of the current detection resistor and voltages at two ends of the MOS, controlling the source voltage of the MOS gate, realizing constant-current start or MOS constant-power start, and preventing larger current impact during power-on.

However, in consideration of the voltage detection accuracy, the resistance heat dissipation, and the power supply efficiency, a current detection resistor having a small resistance value is generally selected. When the insertion load is large, the MOS is required to have large starting dissipation power (power dissipation, PD), and the limitation of the type of the MOS exists; and PD is bigger, and has higher requirements on the safe operation area (safe operate aera, SOA) of MOS.

Disclosure of Invention

In view of this, the embodiments of the present application provide a motherboard, a computing device, and a control method, which reduce the high requirements of a slow start circuit on the PD and the SOA of the MOS, reduce the cost, and improve the power supply efficiency.

In order to solve the above problems, the technical solution provided in the embodiments of the present application is as follows:

a first aspect of the present embodiment provides a motherboard, including: the device comprises a controller, a slow start switch, a charging circuit and a slow start capacitor;

the charging circuit comprises a switch module and a charging resistor;

the first end of the slow start switch is electrically connected with the power supply unit and the first end of the switch module; the second end of the switch module is electrically connected with the first end of the charging resistor; the second end of the slow start switch is electrically connected with the second end of the charging resistor; the second end of the slow start capacitor is grounded;

the slow start control signal output end of the controller is electrically connected with the control end of the slow start switch; the charging control signal output end of the controller is electrically connected with the control end of the switch module; the slow start control signal is used for controlling the working state of the slow start switch; the charging control signal is used for controlling the working state of the switch module;

the controller is used for controlling the switch module to be conducted according to a preset duty ratio before the slow-start switch is closed, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor;

the preset duty ratio is determined according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor.

Preferably, the controller is further configured to control the switch module to be opened and control the slow start switch to be closed when voltages at two ends of the slow start switch are consistent, so that the power supply unit supplies power to the load.

Preferably, the switch module comprises a first switch;

the first end of the first switch is electrically connected with the first end of the slow start switch; the second end of the first switch is electrically connected with the first end of the charging resistor; the charging control signal output end of the controller comprises a first charging control signal output end; the first charging control signal output end is electrically connected with the control end of the first switch; the first charging control signal is used for controlling the working state of the first switch;

and the controller is used for controlling the first switch to be conducted according to a preset duty ratio before the slow-start switch is closed, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor.

Preferably, the switch module comprises a first switch and a second switch; the charging circuit further includes: the first voltage dividing resistor and the second voltage dividing resistor;

the first end of the first switch is electrically connected with the first end of the slow start switch; the second end of the first switch is electrically connected with the first end of the charging resistor; the first end of the first voltage dividing resistor is electrically connected with the first end of the slow start switch; the second end of the first voltage dividing resistor is electrically connected with the first end of the second voltage dividing voltage and the control end of the first switch; the second end of the second voltage dividing resistor is electrically connected with the first end of the second switch; the second end of the second switch is grounded;

the charging control signal output end of the controller comprises a second charging control signal output end; the control end of the second switch is electrically connected with the second charging control signal output end; the second charging control signal is used for controlling the working state of the second switch;

and the controller is used for controlling the second switch to be conducted according to a preset duty ratio before the slow-start switch is closed, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor.

Preferably, the main board further comprises: isolating the inductor;

the first end of the isolation inductor is electrically connected with the second end of the slow start switch; the second end of the isolation inductor is electrically connected with a load.

Preferably, the method further comprises: a third voltage dividing resistor and a fourth voltage dividing resistor;

the first end of the third voltage dividing resistor is electrically connected with the second end of the isolation inductor; the second end of the third voltage dividing resistor is electrically connected with the first end of the fourth voltage dividing voltage and the sampling voltage input end of the controller; the first end of the fourth divided voltage is grounded;

and the controller is used for controlling the slow-start switch to be turned off when the sampling voltage is determined to be smaller than the second preset voltage after the slow-start switch is turned on and off.

Preferably, the switch module further comprises: a diode;

the anode of the diode is electrically connected with the control end of the first switch; the cathode of the diode is electrically connected to the first end of the first switch.

Preferably, the main board further comprises a first capacitor;

the first end of the first capacitor is electrically connected with the second end of the isolation inductor, and the first end of the first capacitor is grounded.

Preferably, the second switch is a metal-oxide-semiconductor field effect transistor, MOS, or triode.

A second aspect of embodiments of the present application provides a computing device comprising: a power supply unit and the above-described main board; the power supply unit is electrically connected with the main board; the power supply unit supplies power to the main board.

From this, the embodiment of the application has the following beneficial effects:

the mainboard that this embodiment provided, the operating condition of controller control switch module and the operating condition who slowly opens the switch, make the power supply unit charge gradually for slowly opening the electric capacity through charging resistor, can not produce great impact when opening the switch slowly in the closure to realize the slow opening of mainboard. The slow start process controls the conduction of the switch module according to a preset duty ratio, and the preset duty ratio is obtained according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor; even if the dissipation power of the charging resistor is smaller, the smaller preset duty ratio is selected to intermittently charge the slow start capacitor, slow start can be completed as well, and the safety problem caused by exceeding the dissipation power can be avoided. The embodiment of the application has no high requirements on the dissipation power and the safe operation area of the slow-start switch, is less limited by the dissipation power of the charging resistor, is more flexible in shape selection, and reduces the cost; the slow start switch with small conduction loss can be adopted, and the power supply efficiency is improved.

Drawings

FIG. 1 is a schematic diagram of a computing device;

fig. 2 is a schematic diagram of a motherboard according to an embodiment of the present application;

fig. 3 is a schematic diagram of another motherboard according to an embodiment of the present application;

fig. 4 is a schematic diagram of another motherboard according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a computing device provided in an embodiment of the present application;

fig. 6 is a flowchart of a control method of a motherboard according to an embodiment of the present application.

Detailed Description

The computing device provided in the embodiments of the present application is not specifically limited to the application scenario, for example, the computing device is described by taking a server as an example, and is not specifically limited to the type of the server, for example, the computing device may be a rack server, a high-density service, or a GPU (graphics processing unit) server, etc. The server may be located in a data center or other areas, and the embodiment of the present application is not specifically limited.

Servers, which are one type of computing device, run faster and are more highly loaded than ordinary computers. The server provides computing or application services to other clients (e.g., PCs, smartphones, etc.) in the network. The server has high-speed CPU operation capability, long-time reliable operation, strong external data throughput capability and better expansibility. Servers are classified from the external form into rack-type, blade-type, tower-type and cabinet-type.

The single board is a common component in the server, and can be in various forms such as a main board, a power management board, a network data exchange board and the like. The single board is provided with an electric connector, and the single board can be plugged on other electrical components (such as another single board) through the electric connector.

The server generally includes a main board and a power supply for supplying power to respective loads of the main board. The voltage level of the power supply provided to the motherboard is not particularly limited, and is described by taking direct current 12V as an example.

The motherboard may include a central processing unit (central processing unit, CPU), memory, controller, electrical connectors, and the like. The central processing unit can be electrically connected with peripheral equipment through an electric connector, for example, the CPU is electrically connected with equipment such as a network card, a display card and the like through the electric connector. The controller may be one or more of a micro control unit (microcontroller unit, MCU), a complex programmable logic device (complex programming logic device, CPLD), a field programmable gate array (field programmable gate array, FPGA).

The loads on the motherboard include CPU, fan, baseboard management controller (baseboard manager controller, BMC), and memory, etc., and the embodiments of the present application do not specifically limit the specific type of memory, for example, the memory includes but is not limited to the following types: dual-inline memory modules (DIMMs), and the like. In addition, the motherboard may include one CPU or a plurality of CPUs.

Hot plug refers to electrically connecting or disconnecting a load without shutting down the power supply.

The power loss (PD) is the difference between the total power input and the total power output of the circuit element at a certain moment. The dissipation power of the transistor is also called collector maximum allowable dissipation power, and refers to the maximum collector dissipation power when the parameter of the transistor is not changed beyond a specified allowable value.

The safe operating area (safe operating area, SOA) is an area formed by a series of voltage and current coordinate points, and the voltage and current of the switching device during normal operation do not exceed the area. Typically, if the device is safe to operate in the SOA region, there is a risk beyond this region.

The application scenario of the embodiments of the present application is described below with reference to the accompanying drawings.

Referring to FIG. 1, a schematic diagram of a computing device is shown.

The computing device comprises a power supply unit (power supply unit, PSU) and a motherboard; the main board comprises a slow start circuit, a direct current/direct current (DC/DC) circuit and a load, wherein the load is a CPU (central processing unit) by way of example; wherein, slowly start the circuit and include: the current detection resistor Rsense, a slow start switching tube Q1 (for example, the switching tube Q1 may be a metal oxide semiconductor field effect transistor (metal oxide semiconductor field effect transistor, MOSFET, abbreviated as MOS tube)), a slow start capacitor C0, a resistor R0, and a hot plug controller 100.

A first end of the current detection resistor Rsense is electrically connected with the power supply unit PSU and a first input end of the hot plug controller 100; the second end of the current detection resistor Rsense is electrically connected with the first end of the slow start switch tube Q1 and the second input end of the hot plug controller 100; the second end of the slow-start switching tube Q1 is electrically connected with the third input end of the hot plug controller 100 and the first end of the DC/DC circuit; the third end of the slow-start switching tube Q1 is electrically connected with the first output end of the hot plug controller 100; the second terminal of the DC/DC circuit is electrically connected to a load, here described as a CPU. It should be appreciated that the load may also be a graphics processor (graphics processing unit, GPU) or the like; the embodiments of the present application are not limited to the type of load. The first end of the DC/DC circuit is also electrically connected with the first end of the slow start capacitor C0 and the first end of the resistor R0; the second end of the slow start capacitor C0 and the second end of the resistor R0 are electrically connected with the ground.

The output voltage of the power supply unit PSU is supplied to the CPU via a voltage change-over of the DC/DC circuit.

In order to prevent the voltage of the bus from being lowered by the impact current during the hot plug of the CPU, in the stage of the CPU plug, the hot plug controller 100 detects the voltages at both ends of the current detection resistor Rsense and the voltages at both ends of the slow start switch tube Q1, controls the gate source voltage of the slow start switch tube Q1, and realizes constant current start or MOS constant power start.

However, the conventional hot plug controller 100 has poor voltage detection accuracy, and the error is 3mV to 5mV; in order to normally start supplying power to the CPU, the voltage generated by the start-up current on the current detection resistor Rsense is required to be greater than 5mV, and accordingly, a large start-up current needs to be set.

When the load is large, in order to ensure the heat dissipation and power supply efficiency of the current detection resistor Rsense, the current detection resistor Rsense is usually selected to have a smaller resistance value. Taking the power supply unit 54V input to supply power to the 3000W load as an example, the resistance value of the current detection resistor Rsense is generally selected to be 1/3mΩ. At this time, in order to satisfy that the voltage generated by the starting current on the current detection resistor Rsense is greater than 5mV, the starting current needs to be set to be greater than 15A; the MOS start-up dissipated power PD is at least 54v×15a=810W.

In addition, the load consumes current from the first terminal of the slow start capacitor C0 before the slow start is completed. If the starting is completed within a prescribed time, the starting current is necessarily required to be larger than the load current, the PD of the slow-start switching tube Q1 is further increased, and the slow-start switching tube Q1 is easily beyond the SOA.

In order to make the PD and SOA of the slow-start switching tube Q1 meet the conditions, there are two schemes as follows:

first kind: MOS with larger SOA and larger PD, such as planar structure MOS or special adapting slow start MOS, is selected.

Obviously, the first scheme has the limitation of type selection, reduces the range of the matched MOS and has high cost; and MOS with larger SOA has larger on-resistance, large on-loss and low efficiency in normal operation.

Second kind: the number of parallel MOS is increased, and the PD required by a single MOS is reduced.

In the second scheme, the number of MOS is increased, resulting in an increase in the area of the motherboard, a decrease in power density, and an increase in cost.

Therefore, the embodiment of the application provides a main board, a computing device and a control method, which realize slow start by charging a slow start capacitor through a charging resistor, eliminate high requirements of a slow start circuit on the PD and the SOA of MOS, reduce cost and improve power supply efficiency.

The examples of the present application are described in further detail below with reference to the drawings and detailed description.

Referring to fig. 2, a schematic diagram of a motherboard according to an embodiment of the present application is shown.

The motherboard 1000 provided in this embodiment of the present application includes: the charging circuit 200 comprises a controller MCU, a charging circuit 200, a slow start capacitor C1, a slow start switching tube Q1 and a load.

The micro control unit MCU adopted by the controller is only one possible implementation manner, and the embodiment of the present application does not specifically limit the type of the controller.

The slow-start switch tube Q1 can be a triode or other types of controllable switch devices such as MOS and the like; fig. 2 illustrates a slow-start switching tube Q1 as an NMOS.

The charging circuit 200 includes a switch module 210 and a charging resistor R1; the switch module 210 is connected in series with the charging resistor R1. The embodiment of the present application is not particularly limited to a specific implementation form of the switch module 210, and may include, for example, one controllable switch device, or may include a plurality of controllable switch devices, where the switch module 210 is used to control on and off of the charging circuit 200. For example, when the switch module 210 is turned on, the power supply unit charges the slow start capacitor C1 through the charging circuit 200, and when the switch module 210 is turned off, the power supply unit stops charging the slow start capacitor C1.

The first end of the slow start switch tube Q1 is used for being electrically connected with the power supply unit PSU, the second end of the slow start switch tube Q1 is electrically connected with the first end of the slow start capacitor C1, and the second end of the slow start capacitor C1 is grounded; the second end of the slow-start switching tube Q1 is also used for electrically connecting a load.

In fig. 2, vin represents the voltage output by the power supply unit PSU; vo represents the voltage at the first end of the slow start capacitor C1, and the second end of the slow start capacitor C1 is grounded, so Vo represents the voltage of the slow start capacitor C1.

The slow start control signal output end of the controller MCU is electrically connected with the control end of the slow start switch tube Q1; the charging control signal output end of the controller MCU is electrically connected with the control end of the switch module 210; the slow start control signal is used for controlling the working state of the slow start switching tube Q1; the charging control signal is used for controlling the working state of the switch module 210.

The controller MCU is configured to control the switch module 210 to be turned on according to a preset duty cycle before the slow start switch tube Q1 is turned on, so that the power supply unit PSU charges the slow start capacitor C1 according to the preset duty cycle through the charging resistor R1.

Further, the controller MCU may further control the switch module 210 to be turned off when the voltages at the two ends of the slow-start switch tube Q1 are consistent, and control the slow-start switch tube Q1 to be turned on, so that the power supply unit PSU supplies power to the load.

The preset duty ratio is obtained according to the dissipation power PD of the charging resistor R1, the voltage Vin of the power supply unit PSU, and the voltage Vo of the slow start capacitor C1. One possible implementation may obtain the preset duty cycle according to the following formula:

in the formula (1), D represents a preset duty ratio.

It should be appreciated that the preset duty cycle d=on time/on period; the maximum value of the preset duty cycle is 1, i.e. the switch module 210 is always turned on.

Therefore, the preset duty ratio D is obtained according to the dissipation power PD of the charging resistor R1, the voltage Vin of the power supply unit PSU, and the voltage Vo of the slow start capacitor C1, and specifically two cases are:

first case: the dissipation power PD of the charging resistor R1 is large enough, and the preset duty ratio D is 1, so that the control switch module 210 is always turned on, and the charging resistor R1 continuously charges the slow start capacitor C1 until the voltages at two ends of the slow start switch tube Q1 are consistent.

Second case: the dissipation power PD of the charging resistor R1 is not large enough, and the preset duty ratio D is smaller than 1, so that the switch module 210 is controlled to be intermittently turned on according to the preset duty ratio D, and the charging resistor R1 intermittently charges the slow start capacitor C1 until the voltages at two ends of the slow start switch tube Q1 are consistent.

When the voltages at the two ends of the slow start switch tube Q1 are consistent, the voltage of the slow start capacitor C1 is charged to be consistent with the voltage of the power supply unit PSU, at the moment, the two ends of the slow start switch tube Q1 have no voltage difference, and the slow start switch tube Q1 is closed, so that larger impact cannot be generated. Therefore, when the voltages at the two ends of the slow start switch tube Q1 are consistent, the control switch module 210 is turned off, and the slow start switch tube Q1 is controlled to be turned on, so that the power supply unit PSU supplies power to the load, and slow start of the main board load is completed.

The voltages at the two ends of the slow start switch tube Q1 are consistent and are not strictly equal, and the voltage difference at the two ends of the slow start switch tube Q1 is within a preset range.

As a possible implementation manner, the voltage consistency at the two ends of the slow-start switching tube Q1 may be specifically realized by setting a voltage sampling circuit at the two ends of the slow-start switching tube Q1 to sample and judge.

In the above process, the slow start switch tube Q1 only plays a role of switching, and communicates the power supply unit PSU with the load; therefore, the slow start switch tube Q1 realizes 0PD start, and the type selection limit of the slow start switch tube Q1 is not provided.

The mainboard that this embodiment provided makes charge resistance for slowly opening the electric capacity and charges gradually through the switch module of control switch, and when slowly opening the electric capacity and charging to slowly opening the switch both ends voltage unanimity, can not produce great impact when opening the switch slowly in the closure to realize the slow opening of mainboard. The slow start process controls the conduction of the switch module according to a preset duty ratio, and the preset duty ratio is obtained according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor; even if the dissipation power of the charging resistor is smaller, the smaller preset duty ratio is selected to intermittently charge the slow start capacitor, slow start can be completed as well, and the safety problem caused by exceeding the dissipation power can be avoided. The embodiment of the application has no high requirements on the dissipation power and the safe operation area of the slow-start switch, is less limited by the dissipation power of the charging resistor, is more flexible in shape selection, and reduces the cost; the slow start switch with small conduction loss can be adopted, and the power supply efficiency is improved.

In one possible implementation, the switch module includes a first switch; the first end of the first switch is electrically connected with the first end of the slow start switch; the second end of the first switch is electrically connected with the first end of the charging resistor; the second end of the charging resistor is electrically connected with the first end of the slow start capacitor.

The charging control signal output end of the controller comprises a first charging control signal output end; the first charging control signal output end is electrically connected with the control end of the first switch; the first charging control signal is used for controlling the working state of the first switch; the controller is specifically used for controlling the first switch to be conducted according to a preset duty ratio before the slow-start switch is closed, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor.

Considering that the first end of the first switch is connected with the first end of the slow start switch, namely, the first end of the slow start switch is connected with the power supply unit, and the voltages of the power supply units are different in different scenes, the first charging control signal output end of the controller needs to provide driving signals with different magnitudes to control the on and off of the first switch in different scenes. In order to provide the driving signal to control the switch module to be turned on more conveniently, in another possible implementation manner, the switch module further comprises a second switch; the on and off of the first switch is controlled through the second switch; the charging circuit further includes: a first voltage dividing resistor and a second voltage dividing resistor.

An implementation of a switch module comprising two switches, namely the first switch and the second switch above, is described below in connection with fig. 3.

Referring to fig. 3, a schematic diagram of another motherboard according to an embodiment of the present application is shown.

The mainboard that this application embodiment provided includes: the power supply comprises a controller MCU, a hot plug controller 300, a charging circuit 200, a slow start capacitor C1, a slow start switching tube Q1, a first resistor R2, an isolation inductor L1, a first capacitor C2, a third voltage dividing resistor R5, a fourth voltage dividing resistor R6 and a DC/DC circuit.

The first end of the slow start switch tube Q1 is used for being electrically connected with the power supply unit PSU, the second end of the slow start switch tube Q1 is electrically connected with the first end of the slow start capacitor C1, and the second end of the slow start capacitor C1 is grounded; the first resistor R2 is connected in parallel to two ends of the slow start capacitor C1.

The charging circuit 200 specifically includes: the charging circuit comprises a switch module, a charging resistor R1, a first voltage dividing resistor R3 and a second voltage dividing resistor R4. Wherein, the switch module includes: a first switch Q2, a second switch Q3, and a diode D1.

On the basis of the slow start circuit shown in fig. 2, as shown in fig. 3, a first end of a first switch Q2 is electrically connected with a first end of a slow start switch tube Q1 and a second end (cathode) of a diode D1; the second end of the first switch Q2 is electrically connected with the first end of the charging resistor R1; the second end of the charging resistor R1 is electrically connected with the first end of the slow start capacitor C1 and the first end of the first resistor R2; the second end of the slow start capacitor C1 is electrically connected with the second end of the first resistor R2.

The first end of the first voltage dividing resistor R3 is electrically connected with the first end of the slow-starting switching tube Q1; the second end of the first voltage dividing resistor R3 is electrically connected with the control end of the first switch Q2, the first end of the second voltage dividing resistor R4 and the first end (anode) of the diode D1; the second end of the second voltage dividing resistor R4 is electrically connected with the first end of the second switch Q3; the second end of the second switch Q3 is electrically connected with the ground; the third terminal of the second switch Q3 is electrically connected to the second output terminal of the MCU.

Fig. 3 illustrates an example in which the first switch Q2 is a PMOS, and the second switch Q3 is a triode.

It should be understood that the first terminal of the first switch Q2 is a source, the second terminal of the first switch Q2 is a drain, and the control terminal of the first switch Q2 is a gate.

The charging control signal output end of the controller MCU comprises a second charging control signal output end; the control end of the second switch Q3 is electrically connected with the second charging control signal output end; the second charging control signal is used for controlling the working state of the second switch Q3.

The controller MCU is used for controlling the second switch Q3 to be conducted according to a preset duty ratio before the slow start switch tube Q1 is closed, enabling the second end of the first voltage dividing resistor R3 to generate voltage division according to the preset duty ratio, driving the first switch Q2 to be conducted according to the preset duty ratio, and enabling the power supply unit PSU to charge the slow start capacitor C1 according to the preset duty ratio through the charging resistor R1.

As in the above embodiment, the preset duty ratio is obtained from the dissipated power of the charging resistor R1, the voltage of the power supply unit PSU, and the voltage of the slow start capacitor C1.

When the second switch Q3 is turned off, the second voltage dividing resistor R4 is not grounded and does not divide voltage, so the voltage at the second end of the first voltage dividing resistor R3 is still the voltage Vin of the power supply unit PSU. At this time, the gate voltage and the source voltage of the first switch Q2 are both the voltage Vin of the power supply unit PSU, and there is no voltage difference between the gate and the source, and the first switch Q2 is turned off.

When the second switch Q3 is turned on, the second voltage dividing resistor R4 is grounded to perform the voltage dividing function, and the voltage Vg at the second end of the first voltage dividing resistor R3 is:

at this time, the source voltage of the first switch Q2 is the voltage Vin of the power supply unit PSU, and the gate voltage of the first switch Q2 is Vg; when the voltage difference between the gate and the source is greater than the turn-on threshold voltage of the first switch Q2, the first switch Q2 is turned on.

The first voltage dividing resistor R3 and the second voltage dividing resistor R4 provide the gate-source voltage for the first switch Q2, and the turn-on threshold voltage V of the first switch Q2 is set to meet the turn-on condition _GS The following conditions need to be satisfied between the two voltage dividing resistors:

in the formula (3), V _GSmax The gate-source withstand voltage of the first switch Q2 is shown.

The switch module 210 charges the slow start capacitor C1 through the charging resistor R1 according to a preset duty cycle.

When the voltages at the two ends of the slow-start switch tube Q1 are consistent, the control switch module 210 is opened, and the slow-start switch tube Q1 is controlled to be closed, so that the power supply unit PSU supplies power to the load. As a possible implementation manner, the embodiment shown in fig. 3 adopts a multi-stage control manner, and the controller MCU controls the hot plug controller 300, so that the hot plug controller 300 can complete voltage detection at two ends of the slow-start switching tube Q1 and complete control of the slow-start switching tube Q1. Wherein, the first input end and the second input end of the hot plug controller 300 are both electrically connected to the first end of the slow start switch tube Q1, and the output end of the hot plug controller 300 is electrically connected to the second end of the slow start switch tube Q1.

In one possible implementation manner, during the slow start process, if the controller MCU determines that the voltage to the power supply unit PSU is abnormal or the voltage of the slow start capacitor C1 is abnormal, the second switch Q3 is immediately controlled to be turned off, so as to prevent the charging resistor R1 from being burned.

The following describes some possible selection manners of component parameters of the motherboard:

the resistance of the charging resistor R1 can be selected with reference to the following formula:

3τ＝3*R1*C1<T0 (4)

in the formula (4), τ is the time constant of the motherboard circuit, i.e. R1×c1; t0 represents the slow start time required for motherboard loading. It will be appreciated that the time from the insertion of the load into the motherboard until the power supply unit is supplying the load normally should not be too long, otherwise the start-up is too slow which can adversely affect the function of the load itself.

The dissipation power PD of the charging resistor R1 needs to be able to withstand the power surge of a slow start charging, and can be selected with reference to the following formula:

in the formula (5), the amino acid sequence of the compound,

since the power surge of a one-time soft start charge gradually decreases with time, equation (5) equates it to a square wave, tp representing the duration of the square wave, to obtain the required dissipated power PD.

One possible selection criterion for the first switch Q2 is:

V _DSmax >vin and

in the formula (6), V _DSmax Representing the firstDrain-source withstand voltage of the switch Q2; i _D The current capacity of the first switch Q2 is shown.

One possible selection criterion for the second switch Q3 is: the collector and base withstand voltages of the second switch Q3 are both greater than the voltage Vin of the power supply unit PSU.

In fig. 3, the diode D1 functions to prevent the gate-source of the first switch Q2 from being broken down. One possible selection criterion for diode D1 is:

Vgs<V _D1 <Vmax (7)

in the formula (7), V _D1 The breakdown voltage of the diode D1 is shown.

As a possible implementation, the diode D1 may be implemented as a zener diode; the embodiment of the present application does not particularly limit the type of the diode D1.

According to the possible component parameter selection modes, the main board provided by the embodiment of the application has smaller component selection limitation, only the requirements of limit situations basically need to be considered, and other parameter limitations are smaller. Therefore, the mainboard provided by the embodiment of the application is easier to select and reduces the cost.

The motherboard provided in this embodiment of the present application further includes fault detection and actions after the completion of the slow start, and a possible implementation is described below.

With continued reference to fig. 3, a first end of the isolation inductor L1 is electrically connected to a second end of the slow-start switching tube Q1; the first end of the isolation inductor L1 is electrically connected with the first end of the third divider resistor R5, the first end of the first capacitor C2 and the first end of the DC/DC circuit; the first end of the third voltage dividing resistor R5, the first end of the fourth voltage dividing resistor R6 and the first input end of the MCU are electrically connected; the second end of the fourth voltage dividing resistor R6 is electrically connected with the ground; the second terminal of the DC/DC circuit is electrically connected to a load.

The controller MCU is further used for controlling the slow-start switching tube Q1 to be disconnected when the voltage of the second end of the isolation inductor L1 is detected to be smaller than a first preset voltage after the slow-start switch is closed.

When the DC/DC circuit is short-circuited, energy is discharged through the grounded first capacitor C2, so that the voltage of the second end of the isolation inductor L1 is gradually reduced and is smaller than a first preset voltage; therefore, after the main board completes the slow start, if the voltage at the second end of the isolation inductor L1 is smaller than the first preset voltage, this indicates that the DC/DC circuit is shorted, so that the slow start switch tube Q1 needs to be controlled in time to be turned off.

It should be understood that, when the second end of the isolation inductor L1 is not electrically connected to the load in other forms without adopting a DC/DC circuit, the voltage of the second end of the isolation inductor L1 is smaller than the first preset voltage, which also indicates that the subsequent stage of the isolation inductor L1 has a high probability of failure, and the slow-start switching tube Q1 needs to be controlled to be turned off.

When the DC/DC circuit is short-circuited, even if larger current exists to enable energy to be grounded through the first capacitor C2, the current flowing through the isolation inductor L1 is still smaller due to the effect of blocking current change of the inductor, the current flowing through the slow start switching tube Q1 is smaller, at this time, the slow start switching tube Q1 is controlled to be disconnected, and the slow start switching tube Q1 can be turned off near 0 current, so that the loss is almost 0.

Meanwhile, due to the isolation effect of the isolation inductor L1, the voltage of the power supply unit PSU does not drop, and other loads which are also powered by the power supply unit PSU are not affected.

The third voltage dividing resistor R5 and the fourth voltage dividing resistor R6 divide the voltage of the second end of the isolation inductor L1 and then provide the divided voltage to the controller MCU, and when the controller MCU detects that the voltage of the second end of the third voltage dividing resistor is smaller than a second preset voltage, the controller MCU judges that the power conversion circuit is short-circuited and controls the slow-start switch-off switch. The implementation mode can ensure that the voltage required to be detected by the controller MCU further accords with the voltage detection range of the controller MCU by controlling the sizes of the third voltage dividing resistor R5 and the fourth voltage dividing resistor R6, and improves the detection precision.

In one possible implementation manner, the resistance values of the third voltage dividing resistor R5 and the fourth voltage dividing resistor R6 may be selected according to the following formula:

in the formula (8), V _MCUmin Representing the minimum voltage that the controller MCU can detect.

PreferablyThe ground is used to determine the position of the ground,the value of (2) can be selected to be 50% of the maximum detection voltage of the controller MCU, and the safety and detection accuracy of the controller MCU can be further ensured.

In order to more intuitively embody the effect of the main board provided by the embodiment of the application, the following takes a load power supply with a power supply of 54V of 3000W as an example, and the actual type selection and scheme comparison of the slow-start switch tube Q1 are performed.

The conventional technology is faced with a power supply of 54V and is used for 3000W load power supply, 5 slow-start MOS parallel circuits with the model of D2PARK are required to be selected as slow-start switches, and the total occupied area is about 10cm ² The on-resistance of the slow start MOS of the model is 10.5mΩ.

The motherboard provided by the embodiment of the application can select 4 common power MOS parallel connection as the slow-start switch, and the total occupied area is about 120mm ² The on-resistance of each normal power MOS is 1.5mΩ. It should be appreciated that the on-resistance is small and the on-loss is small. In contrast, the slow-opening switching efficiency of the main board of the embodiment of the application is improved by 0.2%, and the area is reduced by 80%.

In order to more conveniently implement the driving of the switch module, as a possible implementation manner, based on the embodiment shown in fig. 3, the embodiment of the present application may replace the second switch Q3 with a MOS, which is described below in connection with fig. 4.

Referring to fig. 4, a schematic diagram of another motherboard according to an embodiment of the present application is shown.

The motherboard provided in this embodiment, similar to the embodiment shown in fig. 3, includes: the power supply comprises a controller MCU, a hot plug controller 300, a charging circuit 200, a slow start capacitor C1, a slow start switching tube Q1, a first resistor R2, an isolation inductor L1, a first capacitor C2, a third voltage dividing resistor R5, a fourth voltage dividing resistor R6 and a DC/DC circuit.

The components and electrical connection relationships of each part can be referred to the embodiment shown in fig. 3, and will not be described herein.

Wherein, the second switch Q3 in the embodiment shown in fig. 3 specifically adopts a triode; the transistor needs to be driven by current, which has certain requirements on the current driving capability of the controller MCU.

In this embodiment, the second switch Q3 specifically adopts an NMOS, and the NMOS is used as a voltage-type driving device, and the source thereof is grounded, and only the controller MCU is required to provide the driving voltage to the gate of the second switch Q3. In practical engineering implementations, voltage driving is easier to implement than current driving. Therefore, the embodiment shown in fig. 4 replaces the second switch Q3 with a MOS, and can operate without driving the current second switch Q3, reducing the current driving capability requirement of the controller MCU.

For parameter selection of the second switch Q3 using NMOS, as a possible implementation manner, it is required that the drain-source withstand voltage of the second switch Q3 is greater than the voltage Vin of the power supply unit; and the gate-source turn-on threshold voltage of the second switch Q3 is smaller than the driving voltage provided by the controller MCU.

Based on the motherboard provided in the foregoing embodiment, the embodiment of the present application further provides a computing device, which is described in detail below with reference to the accompanying drawings.

Referring to fig. 5, a schematic diagram of a computing device is provided in an embodiment of the present application.

The computing device provided in the embodiment of the present application includes the power supply unit PSU501 and the motherboard 502 described in the above embodiment.

The power supply unit PSU501 supplies power to the main board 502.

Since the main board 502 described in the above embodiment controls the switch module to be turned on according to the preset duty ratio, the power supply unit charges the slow start capacitor according to the preset duty ratio through the charging resistor, so that the voltage consistency at two ends of the slow start switch is realized, and the slow start switch is closed to finish slow start; the model selection is more flexible, and the cost of the main board 502 is reduced; accordingly, the computing device provided by the embodiment of the application can safely finish slow start, and meanwhile, the overall cost of the computing device is reduced; because the components of the main board 502 are more flexible in type selection, a slow start switch with small conduction loss can be selected, and the power supply efficiency of the computing device provided by the embodiment of the application is improved.

Based on the motherboard and the computing device provided in the foregoing embodiments, the embodiments of the present application further provide a method for controlling the motherboard, which is described in detail below with reference to the accompanying drawings.

Referring to fig. 6, the flowchart of a control method of a motherboard is provided in an embodiment of the present application.

The control method of the mainboard provided by the embodiment of the application is applied to the mainboard described in the embodiment.

The main board comprises: the charging circuit, the slow start capacitor and the slow start switch; the charging circuit at least comprises a switch module and a charging resistor; the switch module is connected in series with the charging resistor.

The first end of the slow start switch is used for being directly and electrically connected with the power supply unit, the second end of the slow start switch is electrically connected with the first end of the slow start capacitor, and the second end of the slow start capacitor is grounded; the second end of the slow start switch is also used for electrically connecting with a load.

The control method of the main board provided by the embodiment of the application comprises the following steps:

s601: before the slow-start switch is closed, the control switch module is conducted according to a preset duty ratio, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor.

The preset duty ratio is obtained according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor.

S602: judging whether the voltages at the two ends of the slow start switch are consistent, if so, executing step S603; if not, returning to step S601 to continue charging the slow start capacitor.

In some implementations, step S602 may implement detection of whether the voltages across the slow start switch are consistent by setting a voltage sampling circuit and a comparison circuit.

S603: the control switch module is opened, and the slow start switch is controlled to be closed, so that the power supply unit supplies power to the load.

According to the control method for the main board, the switch module is controlled to be conducted according to the preset duty ratio, so that the power supply unit charges the slow start capacitor according to the preset duty ratio through the charging resistor, the voltage consistency at two ends of the slow start switch is achieved, and the slow start switch is closed to finish slow start; the preset duty ratio is obtained according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the buffer start capacitor, so that the safety problem caused by exceeding the dissipation power is avoided; the high requirements on the dissipation power and the safe operation area of the slow start switch are not met, the limitation of the dissipation power of the charging resistor is small, the shape selection is more flexible, and the cost is reduced; the slow start switch with small conduction loss can be adopted, and the power supply efficiency is improved.

It should be noted that, in the present description, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the embodiments of the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the embodiments. Thus, the present embodiments are not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A motherboard, comprising: the device comprises a controller, a slow start switch, a charging circuit and a slow start capacitor;

the charging circuit comprises a switch module and a charging resistor;

the first end of the slow start switch is electrically connected with the power supply unit and the first end of the switch module; the second end of the switch module is electrically connected with the first end of the charging resistor; the second end of the slow start switch is electrically connected with the second end of the charging resistor; the second end of the slow start capacitor is grounded;

the slow start control signal output end of the controller is electrically connected with the control end of the slow start switch; the charging control signal output end of the controller is electrically connected with the control end of the switch module; the slow start control signal is used for controlling the working state of the slow start switch; the charging control signal is used for controlling the working state of the switch module;

the controller is used for controlling the switch module to be conducted according to a preset duty ratio before the slow-start switch is closed, so that the power supply unit charges the slow-start capacitor according to the preset duty ratio through the charging resistor;

the preset duty ratio is determined according to the dissipation power of the charging resistor, the voltage of the power supply unit and the voltage of the slow start capacitor.

2. The motherboard of claim 1, wherein the controller is further configured to control the switch module to be opened and the slow start switch to be closed when voltages across the slow start switch are consistent, so that the power supply unit supplies power to the load.

3. The motherboard of claim 1 or 2, wherein the switch module comprises a first switch;

the first end of the first switch is electrically connected with the first end of the slow start switch; the second end of the first switch is electrically connected with the first end of the charging resistor; the charging control signal output end of the controller comprises a first charging control signal output end; the first charging control signal output end is electrically connected with the control end of the first switch; the first charging control signal is used for controlling the working state of the first switch;

and the controller is used for controlling the first switch to be conducted according to the preset duty ratio before the slow start switch is closed, so that the power supply unit charges the slow start capacitor according to the preset duty ratio through the charging resistor.

4. The motherboard of claim 1 or 2, wherein the switch module comprises a first switch and a second switch; the charging circuit further includes: the first voltage dividing resistor and the second voltage dividing resistor;

the first end of the first switch is electrically connected with the first end of the slow start switch; the second end of the first switch is electrically connected with the first end of the charging resistor; the first end of the first voltage dividing resistor is electrically connected with the first end of the slow start switch; the second end of the first voltage dividing resistor is electrically connected with the first end of the second voltage dividing voltage and the control end of the first switch; the second end of the second voltage dividing resistor is electrically connected with the first end of the second switch; the second end of the second switch is grounded;

the charging control signal output end of the controller comprises a second charging control signal output end; the control end of the second switch is electrically connected with the second charging control signal output end; the second charging control signal is used for controlling the working state of the second switch;

and the controller is used for controlling the second switch to be conducted according to the preset duty ratio before the slow start switch is closed, so that the power supply unit charges the slow start capacitor according to the preset duty ratio through the charging resistor.

5. The motherboard of any of claims 1-4, further comprising: isolating the inductor;

the first end of the isolation inductor is electrically connected with the second end of the slow start switch; the second end of the isolation inductor is electrically connected with a load.

6. The motherboard of claim 5, further comprising: a third voltage dividing resistor and a fourth voltage dividing resistor;

the first end of the third voltage dividing resistor is electrically connected with the second end of the isolation inductor; the second end of the third voltage dividing resistor is electrically connected with the first end of the fourth divided voltage and the sampling voltage input end of the controller; the first end of the fourth divided voltage is grounded;

and the controller is used for controlling the slow start switch to be opened when the sampling voltage is determined to be smaller than a second preset voltage after the slow start switch is closed.

7. The motherboard of claim 5 or 6, wherein the switch module further comprises: a diode;

the anode of the diode is electrically connected with the control end of the first switch; the cathode of the diode is electrically connected to the first end of the first switch.

8. The motherboard of any of claims 5-7, further comprising a first capacitor;

the first end of the first capacitor is electrically connected with the second end of the isolation inductor, and the first end of the first capacitor is grounded.

9. The motherboard according to any of claims 4-8, wherein the second switch is a metal-oxide-semiconductor field effect transistor, MOS, or transistor.

10. A computing device, comprising: a power supply unit and the motherboard of any of claims 1-9; the power supply unit is electrically connected with the main board; the power supply unit supplies power to the main board.