Circuit, power system and server for reducing inrush current when plugging circuit card

Abstract

This invention belongs to the field of power system design technology, specifically providing a circuit, power system, and server for reducing inrush current during circuit card insertion and removal. The circuit includes an input power supply, a stepped circuit module, and a surge handling circuit module. The input power supply is connected to the surge handling circuit module via the stepped circuit module. The surge handling circuit module is used to connect to the circuit card. The input power supply outputs high and low levels to the stepped circuit module at set time intervals. The stepped circuit module outputs stepped voltages to the surge handling circuit module based on the received high and low levels. The surge handling module operates in the ohmic region based on the voltage output by the stepped circuit module to reduce the inrush current of the circuit card. By operating the MOSFET in the ohmic region, when the hot-insertion circuit is activated, the MOSFET can be temporarily controlled to operate in the ohmic region to reduce the inrush current.

Description

Technical Field

[0001] This invention relates to the field of power system design technology, specifically to a circuit, power system, and server that reduces inrush current during circuit card insertion and removal. Background Technology

[0002] Many electronic systems allow users to insert or remove various circuit cards without shutting down the entire system; this is commonly known as hot-swapping. In systems with power distributed across multiple cards on a bus, each circuit card contains numerous filtering capacitors. Therefore, hot-swapping generates inrush current spikes, which, if unlimited, can reach hundreds of amperes and damage the circuit card or the entire electronic system. To control the destructive effects of inrush current, hot-swappable circuit cards or the bus must be configured with inrush current limiting circuitry to prevent system malfunction.

[0003] Currently, the most commonly used methods for input inrush current limitation in the industry include: 1. Series negative temperature coefficient thermistor current-limiting resistor; 2. Series power resistor to limit inrush current; 3. Using MOSFET switching transistors to suppress inrush current. The basic principle of these circuits is as follows: A filter capacitor Cin is connected to the output of the DC power supply. When a circuit card is inserted or a load is added, a large inrush current is generated instantaneously because capacitor Cin needs to be charged. At this time, the drain and source of the N-MOSFET on the bus are not conducting. As the delay circuit composed of C1 and R1 applies power to the gate of the MOSFET, the drain and source of the MOSFET gradually conduct, thus effectively reducing the inrush current generated at the moment of power-on. When the gate voltage stabilizes, its drain and source will be in a conducting state. Although the rate of voltage rise of Vgs can be controlled by resistors and capacitors, it is impossible to keep the MOSFET in the ohmic region for a long time, so the inrush current may be excessive. Summary of the Invention

[0004] When the gate voltage stabilizes, its drain and source terminals are in a conducting state. Although the rate of voltage rise of Vgs can be controlled by resistors and capacitors, it is impossible to keep the MOSFET in the ohmic region for a long time, so there is a possibility of excessive inrush current. This invention provides a circuit, power supply system, and server for reducing inrush current during circuit card insertion and removal.

[0005] In a first aspect, the present invention provides a circuit for reducing surge current during circuit card insertion and removal, including an input power supply, a stepped circuit module, and a surge processing circuit module.

[0006] The input power supply is connected to the surge handling circuit module via the stepped circuit module;

[0007] The surge handling circuit module is used to connect to the circuit card;

[0008] Input power is used to set the time interval for outputting high and low levels to the ladder circuit module;

[0009] The stepped circuit module is used to output a stepped voltage to the surge processing circuit module based on the received high and low levels.

[0010] The surge handling module is used to reduce the surge current of the circuit card by operating in the ohmic region based on the voltage output by the ladder circuit module.

[0011] Furthermore, the ladder circuit module includes a voltage follower. The input power supply is connected to the positive input terminal of the voltage follower through a first capacitor and a second diode connected in series. The positive input terminal of the voltage follower is also grounded through the second capacitor. The negative input terminal of the voltage follower is connected to the output terminal of the voltage follower. The output terminal of the voltage follower is also connected through the connection point of the first diode, the first capacitor, and the second diode. The output terminal of the voltage follower is connected to the surge handling module.

[0012] Furthermore, the first capacitor is connected to the anode of the second diode, and the cathode of the second diode is connected to the positive input terminal of the voltage follower;

[0013] The output of the voltage follower is connected to the anode of the first diode, and the cathode of the first diode is connected to the anode of the second diode.

[0014] Furthermore, the surge handling module includes a DC power supply, a MOSFET, and a fourth capacitor;

[0015] The positive terminal of the DC power supply is connected to the drain of the MOSFET through the fourth capacitor, the negative terminal of the DC power supply is connected to the source of the MOSFET, and the gate of the MOSFET is connected to the output of the voltage follower.

[0016] The two ends of the fourth capacitor are connected to the circuit card as the output terminals of the circuit.

[0017] Furthermore, the power supply terminal of the voltage follower is connected to the positive terminal of the DC power supply, the GND terminal of the voltage follower is grounded, and the output terminal of the voltage follower is also grounded through a third capacitor.

[0018] Furthermore, the circuit also includes a reset module;

[0019] The reset module includes a reset power supply, which is connected to the positive input of the voltage follower via a third diode;

[0020] When the voltage follower is working, the reset power supply outputs a high level and the voltage difference between the reset power supply output and the DC power supply is greater than the forward voltage of the third diode.

[0021] In a second aspect, the present invention provides a power supply system for reducing surge current during circuit card insertion and removal, comprising multiple circuit cards distributed on a bus, each circuit card being connected to the circuit for reducing surge current during circuit card insertion and removal as described in the first aspect.

[0022] The system also includes a control module, which is connected to the input power supply via a switching circuit to control the high and low levels of the input power supply output.

[0023] The output of the voltage follower is connected to the control module through a detection circuit. When the detection circuit detects that the output voltage of the voltage follower reaches the output voltage of the DC power supply, it outputs information to the control module, which then controls the input power supply to stop the high-low level switching output action.

[0024] Furthermore, the input power supply of each circuit is connected to a control module through a switching circuit, or a control module is connected to each input power supply through a switching circuit.

[0025] Thirdly, the present invention also provides a server, including the power system described in the second aspect.

[0026] As can be seen from the above technical solutions, the present invention has the following advantages: It uses a MOSFET hot-insertion circuit and adds an external stepped circuit module, controlling the MOSFET in the ohmic region during circuit startup to reduce inrush current. By allowing the MOSFET to operate at the voltage point in the ohmic region, the hot-insertion circuit can control the MOSFET to temporarily operate in the ohmic region during startup, thus reducing inrush current.

[0027] Furthermore, the design principle of this invention is reliable, the structure is simple, and it has a very wide range of application prospects.

[0028] Therefore, it is evident that the present invention has outstanding substantive features and significant progress compared with the prior art, and the beneficial effects of its implementation are also obvious. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a circuit connection diagram of an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of a traditional circuit that uses a MOSFET switch to suppress surge current.

[0032] Figure 3 This is a voltage action diagram of Vgs in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0034] The present invention provides a circuit for reducing surge current during circuit card insertion and removal, including an input power supply, a stepped circuit module, and a surge processing circuit module;

[0035] The input power supply is connected to the surge handling circuit module via the stepped circuit module;

[0036] The surge handling circuit module is used to connect to the circuit card;

[0037] Input power is used to set the time interval for outputting high and low levels to the ladder circuit module;

[0038] The stepped circuit module is used to output a stepped voltage to the surge processing circuit module based on the received high and low levels.

[0039] The surge handling module is used to reduce the surge current of the circuit card by operating in the ohmic region based on the voltage output by the ladder circuit module.

[0040] like Figure 1 As shown, in some embodiments, the ladder circuit module includes a voltage follower OP. The input power supply Vin is connected to the positive input terminal of the voltage follower OP through a first capacitor C1 and a second diode D2 connected in series. The positive input terminal of the voltage follower OP is also grounded through the second capacitor C2. The negative input terminal of the voltage follower OP is connected to the output terminal of the voltage follower OP. The output terminal of the voltage follower OP is also connected through the connection point of the first diode D1, the first capacitor C1, and the second diode D2. The output terminal of the voltage follower OP is connected to the surge processing module.

[0041] In some embodiments, the first capacitor C1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the positive input terminal of the voltage follower OP.

[0042] The output of the voltage follower OP is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the anode of the second diode D2.

[0043] In some embodiments, the surge handling module includes a DC power supply, a MOSFET Q1, and a fourth capacitor Cin;

[0044] The positive terminal of the DC power supply is connected to the drain of MOSFET Q1 through the fourth capacitor Cin, the negative terminal of the DC power supply is connected to the source of MOSFET Q1, and the gate of MOSFET Q1 is connected to the output of voltage follower OP.

[0045] The two ends of the fourth capacitor Cin are connected to the circuit card as the output terminals of the circuit.

[0046] In some embodiments, the power supply terminal of the voltage follower OP is connected to the positive terminal of the DC power supply, the GND terminal of the voltage follower OP is grounded, and the output terminal of the voltage follower OP is also grounded through a third capacitor C3.

[0047] In some embodiments, the circuit further includes a reset module;

[0048] The reset module includes a reset power supply RST, which is connected to the positive input of the voltage follower via a third diode D3;

[0049] When the voltage follower is operating, the reset power supply outputs a high level, and the voltage difference between the reset power supply output and the DC power supply is greater than the forward voltage of the third diode D3. When the reset power supply outputs a low level, the third diode conducts, and the voltage at the positive input terminal of the voltage follower is lowered through the third diode, thus resetting the voltage follower. The reset power supply can be internally controlled by a timing control signal to regulate its output high and low levels, or its output voltage can be controlled by an external control module. The output power supply can also be configured to use the reset power supply output control mode.

[0050] like Figure 2 As shown, the basic principle of the circuit is as follows: A filter capacitor C6 is connected to the output terminal of power supply DC1. When a circuit card is inserted or a load is added, a large inrush current is generated momentarily because capacitor C6 needs to be charged. At this time, the drain and source of the MOSFET Q2 on the bus are not conducting. As the delay circuit composed of C5 and R1 applies power to the gate of Q2, the drain and source of the MOSFET gradually conduct, effectively reducing the inrush current generated at power-on. When the gate voltage stabilizes, its drain and source will be in a conducting state. Here, the MOSFET is an N-MOSFET.

[0051] Initially, the voltage across C5 is 0V. The input voltage charges C5 through R1. Ultimately, the operating state of Q2 is determined by the voltage at the Vgs terminal.

[0052] When Vgs < Vgs(th):

[0053] Vgs represents the bias difference from the gate to the source, and Vgs(th) is the critical voltage of the material. At this time, the MOSFET is in the cutoff region (cutoff, subthreshold or weak - inversion mode), acting like an open circuit.

[0054] When Vgs > Vgs(th) and Vds > Vgs(th):

[0055] Here, Vds is the voltage from the drain to the source of the NMOS. Then this NMOS is in the conducting state. The Vds characteristic is like a linear resistor and will decrease as the Vgs voltage increases. This region is called the linear region (triode region or ohmic region) (linear region, triode mode or ohmic mode).

[0056] When Vgs > Vgs(th) and Vds < Vgs(th):

[0057] This metal - oxide - semiconductor field - effect transistor is in the conducting state, operating in the saturation region (active region) (saturation or active mode), forming a channel for current to pass through.

[0058] As Figure 1 shown in the circuit, at the initial state of the circuit, the state of Vin is low - level; the level of capacitor C2 is zero, so the output Vo of the operational amplifier is also low - level (voltage follower); diodes D1 and D2 are cutoff. In the first step, Vin changes from low - level to high - level. Capacitors C1 and C2 are in series, and capacitors C1 and C2 are respectively charged. The output Vo of the operational amplifier is equal to the level of capacitor C2. After climbing one step, Vin returns to low - level, D2 changes from conducting to cutoff, D1 changes from cutoff to conducting, and the output Vo of the operational amplifier reversely charges capacitor C1. In one repeated action, Vin changes from low to high. The charge that was reversely charged into C1 before is transferred to C2, the level of C2 is raised by one step, and the output of the operational amplifier also climbs one step. Then, Vin returns to low - level again, and C1 is reversely charged. Repeating this cycle, the output of the operational amplifier climbs in a step - by - step manner. It stops when it climbs to the DC voltage, and the RST terminal has a reset function.

[0059] If the DC voltage is 12V and the Vin voltage is 3.3V, through this circuit, the voltage of Vgs can be made to increase step - by - step, as Figure 3 shown, allowing Vgs to work in the ohmic region for a longer time and reducing the inrush current.

[0060] This invention provides a power supply system for reducing inrush current during circuit card insertion and removal, comprising multiple circuit cards distributed on a bus, each circuit card being connected to a circuit for reducing inrush current during circuit card insertion and removal; the circuit for reducing inrush current during circuit card insertion and removal includes an input power supply, a stepped circuit module, and a surge processing circuit module.

[0061] The input power supply is connected to the surge handling circuit module via the stepped circuit module;

[0062] The surge handling circuit module is used to connect to the circuit card;

[0063] Input power is used to set the time interval for outputting high and low levels to the ladder circuit module;

[0064] The stepped circuit module is used to output a stepped voltage to the surge processing circuit module based on the received high and low levels.

[0065] The surge handling module is used to reduce the surge current of the circuit card by operating in the ohmic region based on the voltage output by the ladder circuit module.

[0066] The system also includes a control module, which is connected to the input power supply via a switching circuit to control the high and low levels of the input power supply output.

[0067] The output of the voltage follower is connected to the control module through a detection circuit. When the detection circuit detects that the output voltage of the voltage follower reaches the output voltage of the DC power supply, it outputs information to the control module, which then controls the input power supply to stop the high-low level switching output action.

[0068] The stepped circuit module includes a voltage follower OP. The input power supply Vin is connected to the positive input terminal of the voltage follower OP through a first capacitor C1 and a second diode D2 connected in series. The positive input terminal of the voltage follower OP is also grounded through the second capacitor C2. The negative input terminal of the voltage follower OP is connected to the output terminal of the voltage follower OP. The output terminal of the voltage follower OP is also connected through the connection point of the first diode D1, the first capacitor C1, and the second diode D2. The output terminal of the voltage follower OP is connected to the surge handling module.

[0069] The first capacitor C1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the positive input terminal of the voltage follower OP.

[0070] The output of the voltage follower OP is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the anode of the second diode D2.

[0071] The surge handling module includes a DC power supply, a MOSFET Q1, and a fourth capacitor Cin;

[0072] The positive terminal of the DC power supply is connected to the drain of MOSFET Q1 through the fourth capacitor Cin, the negative terminal of the DC power supply is connected to the source of MOSFET Q1, and the gate of MOSFET Q1 is connected to the output of voltage follower OP.

[0073] The two ends of the fourth capacitor Cin are connected to the circuit card as the output terminals of the circuit.

[0074] The power supply terminal of the voltage follower OP is connected to the positive terminal of the DC power supply, the GND terminal of the voltage follower OP is grounded, and the output terminal of the voltage follower OP is also grounded through the third capacitor C3.

[0075] The circuit also includes a reset module;

[0076] The reset module includes a reset power supply RST, which is connected to the positive input of the voltage follower via a third diode D3;

[0077] When the voltage follower is working, the reset power supply outputs a high level and the voltage difference between the reset power supply output voltage and the DC power supply voltage is greater than the forward voltage of the third diode D3.

[0078] In some embodiments, the input power supply of each circuit is connected to a control module through a switching circuit, or a control module is connected to each input power supply through a switching circuit.

[0079] The present invention also provides a server, including a power system, wherein the power system includes multiple circuit cards distributed on a bus, each circuit card being connected to a circuit for reducing inrush current when the circuit card is inserted or removed; the circuit for reducing inrush current when the circuit card is inserted or removed includes an input power supply, a stepped circuit module, and a surge processing circuit module.

[0080] The input power supply is connected to the surge handling circuit module via the stepped circuit module;

[0081] The surge handling circuit module is used to connect to the circuit card;

[0082] Input power is used to set the time interval for outputting high and low levels to the ladder circuit module;

[0083] The stepped circuit module is used to output a stepped voltage to the surge processing circuit module based on the received high and low levels.

[0084] The surge handling module is used to reduce the surge current of the circuit card by operating in the ohmic region based on the voltage output by the ladder circuit module.

[0085] The system also includes a control module, which is connected to the input power supply via a switching circuit to control the high and low levels of the input power supply output.

[0086] The output of the voltage follower is connected to the control module through a detection circuit. When the detection circuit detects that the output voltage of the voltage follower reaches the output voltage of the DC power supply, it outputs information to the control module, which then controls the input power supply to stop the high-low level switching output action.

[0087] The stepped circuit module includes a voltage follower OP. The input power supply Vin is connected to the positive input terminal of the voltage follower OP through a first capacitor C1 and a second diode D2 connected in series. The positive input terminal of the voltage follower OP is also grounded through the second capacitor C2. The negative input terminal of the voltage follower OP is connected to the output terminal of the voltage follower OP. The output terminal of the voltage follower OP is also connected through the connection point of the first diode D1, the first capacitor C1, and the second diode D2. The output terminal of the voltage follower OP is connected to the surge handling module.

[0088] The first capacitor C1 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the positive input terminal of the voltage follower OP.

[0089] The output of the voltage follower OP is connected to the anode of the first diode D1, and the cathode of the first diode D1 is connected to the anode of the second diode D2.

[0090] The surge handling module includes a DC power supply, a MOSFET Q1, and a fourth capacitor Cin;

[0091] The positive terminal of the DC power supply is connected to the drain of MOSFET Q1 through the fourth capacitor Cin, the negative terminal of the DC power supply is connected to the source of MOSFET Q1, and the gate of MOSFET Q1 is connected to the output of voltage follower OP.

[0092] The two ends of the fourth capacitor Cin are connected to the circuit card as the output terminals of the circuit.

[0093] The power supply terminal of the voltage follower OP is connected to the positive terminal of the DC power supply, the GND terminal of the voltage follower OP is grounded, and the output terminal of the voltage follower OP is also grounded through the third capacitor C3.

[0094] The circuit also includes a reset module;

[0095] The reset module includes a reset power supply RST, which is connected to the positive input of the voltage follower via a third diode D3;

[0096] When the voltage follower is working, the reset power supply outputs a high level and the voltage difference between the reset power supply output voltage and the DC power supply voltage is greater than the forward voltage of the third diode D3.

[0097] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the invention should also be covered within the protection scope of the invention. Therefore, the protection scope of the invention should be determined by the scope of the claims.

Claims

1. A circuit for reducing inrush current when a circuit card is plugged in, characterized by The circuit comprises an input power supply, a ladder circuit module and a surge processing circuit module; The input power supply is connected with the ladder circuit module and the surge processing circuit module; The surge processing circuit module is used for connecting with a circuit card; The input power supply is used for setting time interval to output high and low levels to the ladder circuit module; The ladder circuit module is used for outputting ladder voltage to the surge processing circuit module according to the received high and low levels; The surge processing module is used for working in ohmic region to reduce the surge current of the circuit card according to the voltage outputted by the ladder circuit module; The ladder circuit module comprises a voltage follower, the input power supply is connected with the positive input terminal of the voltage follower through a series connection of a first capacitor and a second diode, the positive input terminal of the voltage follower is also connected with the ground through a second capacitor, the negative input terminal of the voltage follower is connected with the output terminal of the voltage follower, the output terminal of the voltage follower is also connected with the connection point of the first capacitor and the second diode through a first diode, and the output terminal of the voltage follower is connected with the surge processing module; The first capacitor is connected with the anode of the second diode, and the cathode of the second diode is connected with the positive input terminal of the voltage follower; The output terminal of the voltage follower is connected with the anode of the first diode, and the cathode of the first diode is connected with the anode of the second diode.

2. The circuit for reducing inrush current upon plugging of a circuit card as recited in claim 1, wherein, The surge processing module comprises a DC power supply, a MOS tube and a fourth capacitor; The positive terminal of the DC power supply is connected with the drain of the MOS tube through the fourth capacitor, the negative terminal of the DC power supply is connected with the source of the MOS tube, and the gate of the MOS tube is connected with the output terminal of the voltage follower; The two terminals of the fourth capacitor are connected with the output terminal of the circuit and the circuit card.

3. The circuit for reducing insertion surge current of a circuit card according to claim 2, wherein, The power terminal of the voltage follower is connected with the positive terminal of the DC power supply, the GND terminal of the voltage follower is connected with the ground, and the output terminal of the voltage follower is also connected with the ground through a third capacitor.

4. The circuit for reducing inrush current upon plugging of a circuit card as recited in claim 3, wherein, The circuit further comprises a reset module; The reset module comprises a reset power supply, and the reset power supply is connected with the positive input terminal of the voltage follower through a third diode; When the voltage follower works, the reset power supply outputs high level, and the voltage difference between the voltage outputted by the reset power supply and the voltage of the DC power supply is greater than the conduction voltage of the third diode.

5. A power supply system for reducing inrush current when a circuit card is plugged in, characterized by The system comprises a plurality of circuit cards distributed on a bus, each circuit card is connected with the circuit for reducing the surge current when the circuit card is plugged in or unplugged as claimed in any one of claims 1 to 4; The system further comprises a control module, and the control module is connected with the input power supply through a switch circuit, and is used for controlling the high and low levels outputted by the input power supply.

6. The power system of claim 5, wherein, The input power supply of each circuit is connected with one control module through one switch circuit, or one control module is connected with each input power supply through a switch circuit.

7. A server, characterized by The system comprises the power supply system as claimed in any one of claims 5 to 6.

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