Hot plug circuit and electronic device

Abstract

The application discloses a hot plug circuit and electronic equipment, and relates to the technical field of electronics, and comprises a switching unit, a capacitor unit and a charge-discharge circuit; the first end of the switching unit is connected with a power input end, the second end is connected with a power output end, and the switching unit is a first MOS tube; the first end of the capacitor unit is connected with the second end of the switching unit, and the second end is connected with the third end of the switching unit; the first end of the charge-discharge circuit is connected with the power input end, the second end is connected with the second end of the capacitor unit, and the third end is grounded; when the hot plug circuit is powered on, the charge-discharge circuit is used for nonlinear control of the discharge current of the capacitor unit, so that the current of the switching unit gradually increases and is maintained within a preset current value. Through the nonlinear control of the charge-discharge circuit on the capacitor unit, the effect of the first MOS tube is approximately achieved, that is, the effect of 'constant power protection + constant current protection', the use cost is low, there is no risk of insufficient supply, and the production cost and efficiency of the equipment are not affected.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a hot-swappable circuit and electronic device. Background Technology

[0002] Currently, hot-swapping, also known as live plugging and unplugging, refers to inserting and removing electronic devices, such as high-power single disks, without disconnecting the power supply to the device.

[0003] Existing hot-swap circuits mainly use hot-swap controllers, such as TPS24771, TPS24711, TPS5064, and LTC4211. Their advantages are: maturity, reliability, complete functions, and various protection mechanisms, which can provide transient overpower protection and overcurrent protection for MOSFETs.

[0004] However, the pins of various hot-swappable controllers are incompatible and cannot be replaced. Furthermore, hot-swappable controllers are expensive to use and there is a risk of insufficient supply, which in turn affects the production cost and efficiency of the equipment. Summary of the Invention

[0005] This invention provides a hot-swappable circuit and electronic device to solve the technical problem in the related art that using a hot-swappable controller to protect the MOSFET of electronic devices is costly and carries the risk of insufficient supply, thereby affecting the production cost and efficiency of electronic devices.

[0006] In a first aspect, a hot-swappable circuit is provided, comprising: a switching unit, a capacitor unit, and a charging / discharging circuit;

[0007] The first end of the switching unit is connected to the power input terminal and the second end is connected to the power output terminal. The switching unit is a first MOSFET.

[0008] The first end of the capacitor unit is connected to the second end of the switch unit, and the second end is connected to the third end of the switch unit.

[0009] The first terminal of the charging / discharging circuit is connected to the power input terminal, the second terminal is connected to the second terminal of the capacitor unit, and the third terminal is grounded; and

[0010] When the hot-swap circuit is powered on, the charging and discharging circuit is used to perform nonlinear control on the discharge current of the capacitor unit, so that the current conducted by the switching unit gradually increases and is maintained within a preset current value.

[0011] In some embodiments, the charging and discharging circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a second capacitor, a fifth capacitor, and a transistor;

[0012] The first end of the first resistor is connected to the power input terminal, and the second end is connected to the first end of the second resistor;

[0013] The second end of the second resistor is connected to the second end of the capacitor unit;

[0014] The first end of the third resistor is connected to the second end of the first resistor, and the second end of the third resistor is connected to the collector of the transistor.

[0015] The first end of the fourth resistor is connected to the second end of the first resistor, and the second end is connected to the base of the transistor.

[0016] The first terminal of the second capacitor is connected to the base of the transistor, and the second terminal is connected to the emitter of the transistor and grounded.

[0017] The first terminal of the fifth capacitor is connected to the source of the first MOS transistor, and the second terminal is connected to the gate of the first MOS transistor.

[0018] When the hot-swappable circuit is powered on, the fourth resistor, the first capacitor, and the transistor are used to perform nonlinear control on the discharge current of the capacitor unit.

[0019] In some embodiments, the hot-swap circuit further includes:

[0020] The first delay circuit has a first terminal connected to the power input terminal, a second terminal connected to the third terminal of the charging and discharging circuit, and the third terminal grounded.

[0021] When the hot-swappable circuit is powered on, the first delay circuit is used to control the start time of discharge of the capacitor unit.

[0022] In some embodiments, the first delay circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a third capacitor, and a first MOSFET;

[0023] The first end of the fifth resistor is connected to the power input terminal, and the second end is connected to the gate of the first MOS transistor.

[0024] The first end of the sixth resistor is connected to the power input terminal, and the second end is connected to the drain of the first MOS transistor.

[0025] The first end of the seventh resistor is connected to the second end of the fifth resistor, and the second end is connected to the source of the first MOS transistor.

[0026] The first terminal of the third capacitor is connected to the gate of the first MOS transistor, and the second terminal is connected to the source of the first MOS transistor and grounded.

[0027] In some embodiments, the transistor is an NPN transistor.

[0028] In some embodiments, the hot-swap circuit further includes:

[0029] The second delay circuit has a first terminal connected to the power input terminal, a second terminal connected to the third terminal of the switching unit, and a third terminal grounded.

[0030] When the hot-swappable circuit is powered on, the second delay circuit is used to control the disconnection time between the first and third terminals of the switching unit.

[0031] In some embodiments, the second delay circuit includes an eighth resistor, a ninth resistor, a tenth resistor, a fourth capacitor, a second MOS transistor, and a relay;

[0032] The first end of the eighth resistor is connected to the power input terminal, and the second end is connected to the gate of the second MOS transistor.

[0033] The first end of the ninth resistor is connected to the second end of the eighth resistor, and the second end is connected to the source of the second MOS transistor.

[0034] The first terminal of the fourth capacitor is connected to the gate of the second MOS transistor, and the second terminal is connected to the source of the second MOS transistor and grounded.

[0035] The first end of the tenth resistor is connected to the power input terminal, and the second end is connected to the first end of the control coil of the relay.

[0036] The second end of the control coil of the relay is connected to the drain of the second MOS transistor, the stationary contact of the relay is connected to the power input terminal, and the moving contact is connected to the third end of the switching unit.

[0037] In some embodiments, the relay is a normally closed relay.

[0038] In some embodiments, the capacitor unit is a first capacitor, with a first terminal connected to the drain of the first MOS transistor and a second terminal connected to the gate of the first MOS transistor.

[0039] Secondly, an electronic device is provided, including the aforementioned hot-swappable circuit.

[0040] The beneficial effects of the technical solution provided by this invention include:

[0041] This invention provides a hot-swappable circuit and electronic device. The hot-swappable circuit includes a capacitor unit and a charging / discharging circuit. The charging / discharging circuit performs nonlinear control on the discharge current of the capacitor unit, gradually increasing the current of the switching unit and maintaining it within a preset current value. This reduces the peak power of the first MOSFET and limits its maximum on-state current, improving the safety of the first MOSFET. In other words, this invention achieves an effect similar to "constant power protection + constant current protection" for the first MOSFET through nonlinear control of the capacitor unit via the charging / discharging circuit. Both the charging / discharging circuit and the capacitor unit can be built using discrete components, resulting in low cost and eliminating the risk of supply shortages. It does not affect equipment production costs or efficiency and can replace existing solutions using hot-swappable controllers. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A schematic block diagram of a hot-swappable circuit provided in an embodiment of the present invention;

[0044] Figure 2 This is a circuit diagram of a hot-swappable circuit provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] This invention provides a hot-swap circuit that solves the technical problem that the existing technology uses a hot-swap controller to protect the MOSFETs of electronic devices, which has high cost and the risk of insufficient supply, thus affecting the production cost and efficiency of electronic devices.

[0047] See Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a hot-swappable circuit, including: a switching unit, a capacitor unit, and a charging and discharging circuit;

[0048] The first terminal of the switching unit is connected to the power input terminal, and the second terminal is connected to the power output terminal. The first terminal of the capacitor unit is connected to the second terminal of the switching unit, and the second terminal is connected to the third terminal of the switching unit. The first terminal of the charging / discharging circuit is connected to the power input terminal, the second terminal is connected to the second terminal of the capacitor unit, and the third terminal is grounded. Optionally, the switching unit is a first MOSFET T1, and the source of the first MOSFET T1 is connected to the power input terminal V. IN Connection, drain and power output terminal V OUT The capacitor unit is a first capacitor C1, with its first end connected to the drain of the first MOS transistor T1 and its second end connected to the gate of the first MOS transistor T1.

[0049] When the hot-swap circuit is powered on, the charging and discharging circuit performs non-linear control on the discharge current of the capacitor unit, so that the current turned on by the switching unit gradually increases and is maintained within a preset current value. That is, the charging and discharging circuit performs non-linear control on the discharge current of the first capacitor C1, so that the current turned on by the first MOSFET T1 gradually increases and is maintained within a preset current value.

[0050] The hot-swap circuit in this embodiment of the invention includes a capacitor unit and a charging / discharging circuit. The charging / discharging circuit performs nonlinear control on the discharge current of the capacitor unit, gradually increasing the current turned on by the switching unit and maintaining it within a preset current value. This reduces the peak power of the first MOSFET and limits its maximum on-state current, thus improving the safety of the first MOSFET. In other words, this invention achieves an effect similar to "constant power protection + constant current protection" for the first MOSFET through the nonlinear control of the capacitor unit by the charging / discharging circuit. Both the charging / discharging circuit and the capacitor unit can be built using discrete components, resulting in low cost and eliminating the risk of supply shortages. It does not affect equipment production costs or efficiency and can replace existing solutions using hot-swap controllers.

[0051] Furthermore, based on achieving near-constant power protection + constant current protection for the first MOSFET, under the same specifications, the first MOSFET has a larger safe operating area margin. It is also possible to use a smaller and cheaper MOSFET while ensuring the same safe operating area margin, thereby reducing the PCB board area and device cost of the hot-swappable circuit.

[0052] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 2 As shown, the charging and discharging circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a second capacitor C2, a fifth capacitor C5, and a transistor Q1.

[0053] The first terminal of the first resistor R1 is connected to the power input terminal V. IN The first terminal of the first resistor R1 is connected to the second terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the second terminal of the capacitor unit. The first terminal of the third resistor R3 is connected to the second terminal of the first resistor R1, and the second terminal of the third resistor R3 is connected to the collector of the transistor Q1. The first terminal of the fourth resistor R4 is connected to the second terminal of the first resistor R1, and the second terminal is connected to the base of the transistor Q1. The first terminal of the second capacitor C2 is connected to the base of the transistor Q1, and the second terminal is connected to the emitter of the transistor Q1 and grounded. The first terminal of the fifth capacitor C5 is connected to the source of the first MOSFET T1, and the second terminal is connected to the gate of the first MOSFET T1. When the hot-swap circuit is powered on, the fourth resistor R4, the second capacitor C2, and the transistor Q1 are used to perform nonlinear control on the discharge current of the capacitor unit (first capacitor C1).

[0054] As an optional implementation, in one embodiment of the invention, the hot-swap circuit further includes: a first delay circuit, wherein a first terminal of the first delay circuit is connected to the power input terminal VIN, a second terminal is connected to the third terminal of the charging and discharging circuit, and the third terminal is grounded.

[0055] When the hot-swappable circuit is powered on, the first delay circuit is used to control the start time of discharge of the capacitor unit.

[0056] Further, see Figure 2 As shown, the first delay circuit includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a third capacitor C3, and a second MOS transistor T2.

[0057] The first terminal of the fifth resistor R5 is connected to the power input terminal V. IN The first terminal of the resistor R6 is connected to the gate of the first MOS transistor T2. The second terminal of the resistor R6 is connected to the power input terminal V. IN The first terminal of the seventh resistor R7 is connected to the second terminal of the fifth resistor R5, and the second terminal is connected to the source of the first MOS transistor T2. The first terminal of the third capacitor C3 is connected to the gate of the first MOS transistor T2, and the second terminal is connected to the source of the first MOS transistor T2 and grounded.

[0058] Specifically, when the fourth resistor R4 charges the third capacitor C3 to the turn-on threshold of the second MOSFET T2, the second MOSFET T2 turns on, thus controlling the turn-on time of the second MOSFET T2. This converts the hot-swap circuit into a "load switch" circuit, avoiding the ringing phase at the moment of insertion and improving circuit reliability. Furthermore, this circuit can be controlled by an external enable signal to control the turn-on time of the hot-swap circuit, and can also be turned off using an external enable signal, thereby powering down the device.

[0059] As an optional implementation, in one embodiment of the invention, the hot-swap circuit further includes: a second delay circuit, wherein a first terminal of the second delay circuit is connected to the power input terminal V. IN The second terminal is connected to the third terminal of the switch unit, and the third terminal is grounded.

[0060] When the hot-swappable circuit is powered on, the second delay circuit is used to control the disconnection time between the first and third terminals of the switching unit.

[0061] Further, see Figure 2 As shown, the second delay circuit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a fourth capacitor C4, a third MOS transistor T3, and a relay RL1.

[0062] The first end of the eighth resistor R8 is connected to the power input terminal, and the second end is connected to the gate of the third MOSFET T3. The first end of the ninth resistor R9 is connected to the second end of the eighth resistor R8, and the second end is connected to the source of the third MOSFET T3. The first end of the fourth capacitor C4 is connected to the gate of the third MOSFET T3, and the second end is connected to the source of the third MOSFET T3 and grounded. The first end of the tenth resistor R10 is connected to the power input terminal, and the second end is connected to the first end of the control coil of the relay RL1. The second end of the control coil of the relay RL1 is connected to the drain of the third MOSFET T3. The stationary contact of the relay RL1 is connected to the power input terminal, and the moving contact is connected to the third terminal of the switching unit (the gate of the first MOSFET T1).

[0063] Without the second delay circuit, at the moment the electronic device is powered on, due to the presence of the first capacitor, the gate voltage of the first MOSFET T1 cannot fully keep up with the source voltage, generating a VGS voltage. If the VGS voltage exceeds the turn-on threshold of the first MOSFET T1, the first MOSFET T1 will be in a conducting state, i.e., the first MOSFET T1 exhibits a "pre-turn-on" phenomenon. This will lead to a very high inrush current. Excessive inrush current will become a strong source of interference, causing EMC problems, and the hot-swap circuit will become meaningless. Therefore, the relay RL1 can be a normally closed relay. When the device is powered on, the relay RL1 is in a "closed" state, ensuring that the gate and source of the first MOSFET T1 are at the same potential. Specifically, when the eighth resistor R8 charges the fourth capacitor C4 to the turn-on threshold of the third MOSFET T3, the third MOSFET T3 turns on, and the power input terminal V... IN A circuit is formed by the tenth resistor R10, relay RL1, and the third MOSFET T3, driving the electromagnetic coil of relay RL1. Relay RL1 will open its normally closed contact. At this time, the voltage difference between the gate and source of the first MOSFET T1 will be determined by the charging status of the Miller capacitor. That is, before the eighth resistor R8 charges the fourth capacitor C4 to the point where the third MOSFET T3 turns on, the voltage between the gate and source of the first MOSFET T1 will remain at the same potential, and the first MOSFET T1 will remain in the off state, thus eliminating the "pre-turn-on" phenomenon.

[0064] See Figure 2 As shown, the method for estimating the maximum on-state current or inrush current of the first MOSFET T1 during the entire conduction process in this embodiment of the invention is as follows:

[0065] The gate charging current i of the first MOSFET T1 g for:

[0066] Where τ1=C5*(R2+R3);

[0067] The time t for the hot-swap circuit to start up and stabilize gs satisfy:

[0068] Among them, Q gs This refers to the gate charge of the first MOSFET T1, which can be found in the datasheet of the first MOSFET.

[0069] The Miller plateau voltage V of the first MOSFET T1 can be obtained. miller for:

[0070]

[0071] Among them, V xThe voltage at the common point of R2 and R3;

[0072] The charging current i of the first capacitor C1 C1 for:

[0073]

[0074] The hold time of the Miller plateau of the first MOSFET T1 can be obtained:

[0075] C gs The gate junction charge of the first MOSFET T1 can be found in the datasheet for the first MOSFET T1.

[0076] The maximum on-state current or inrush current of the first MOSFET T1 can be obtained as follows:

[0077]

[0078] The peak power of the first MOSFET T1 in this embodiment of the invention is estimated as follows throughout the entire conduction process:

[0079] After the first delay circuit is activated, the source of the second MOSFET T2 is at the same potential as ground. Therefore:

[0080] Where τ2=C2*R4;

[0081] The base current of transistor Q1 I s V is the reverse saturation current between the base and emitter, which can be found in the datasheet of the first MOSFET T1; n is the emitter coefficient, typically taken as 1.5; V T This is the voltage equivalent to temperature, typically taken as 0.026V at room temperature (300K).

[0082] i C1 =β*i B β is the common-emitter DC amplification factor. From this formula, it can be seen that the charging current of the first capacitor C1 is nonlinearized. Let... The time t2 when the current in the first capacitor C1 reaches the Miller plateau can be calculated.

[0083] calculate

[0084] The voltage difference V between the source and drain of the first MOSFET T1 SD = (1-α)*V IN Among them, the proportionality coefficient

[0085] Peak power P max =V SD *i inrush= (1-α)*V IN *i inrush .

[0086] If the first capacitor C1 is not nonlinearly adjusted, the peak power is approximately equal to V. IN *i inrush It can be seen that after adding nonlinear adjustment to the first capacitor C1, the peak power of the first MOSFET T1 is reduced to 1-α times. By adjusting the value of α, the peak power of the first MOSFET T1 can be adjusted.

[0087] This invention provides an electronic device including the aforementioned hot-swappable circuit.

[0088] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0089] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A hot-swappable circuit, characterized in that, include: Switching unit, capacitor unit, charging / discharging circuit, and second delay circuit; The first end of the switching unit is connected to the power input terminal and the second end is connected to the power output terminal. The switching unit is a first MOSFET. The first end of the capacitor unit is connected to the second end of the switch unit, and the second end is connected to the third end of the switch unit. The first terminal of the charging / discharging circuit is connected to the power input terminal, the second terminal is connected to the second terminal of the capacitor unit, and the third terminal is grounded; and When the hot-swappable circuit is powered on, the charging and discharging circuit is used to perform nonlinear control on the discharge current of the capacitor unit, so that the current of the switching unit gradually increases and is maintained within a preset current value. When the hot-swappable circuit is powered on, the second delay circuit is used to control the disconnection time between the first and third terminals of the switching unit. The second delay circuit includes an eighth resistor, a ninth resistor, a tenth resistor, a fourth capacitor, a second MOS transistor, and a relay. The first end of the eighth resistor is connected to the power input terminal, and the second end is connected to the gate of the second MOS transistor. The first end of the ninth resistor is connected to the second end of the eighth resistor, and the second end is connected to the source of the second MOS transistor. The first terminal of the fourth capacitor is connected to the gate of the second MOS transistor, and the second terminal is connected to the source of the second MOS transistor and grounded. The first end of the tenth resistor is connected to the power input terminal, and the second end is connected to the first end of the control coil of the relay. The second end of the control coil of the relay is connected to the drain of the second MOS transistor, the stationary contact of the relay is connected to the power input terminal, and the moving contact is connected to the third end of the switching unit.

2. The hot-swappable circuit according to claim 1, characterized in that: The charging and discharging circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a second capacitor, a fifth capacitor, and a transistor; The first end of the first resistor is connected to the power input terminal, and the second end is connected to the first end of the second resistor; The second end of the second resistor is connected to the second end of the capacitor unit; The first end of the third resistor is connected to the second end of the first resistor, and the second end of the third resistor is connected to the collector of the transistor. The first end of the fourth resistor is connected to the second end of the first resistor, and the second end is connected to the base of the transistor. The first terminal of the second capacitor is connected to the base of the transistor, and the second terminal is connected to the emitter of the transistor and grounded. The first terminal of the fifth capacitor is connected to the source of the first MOS transistor, and the second terminal is connected to the gate of the first MOS transistor. When the hot-swappable circuit is powered on, the fourth resistor, the first capacitor, and the transistor are used to perform nonlinear control on the discharge current of the capacitor unit.

3. The hot-swappable circuit according to claim 2, characterized in that, Also includes: The first delay circuit has a first terminal connected to the power input terminal, a second terminal connected to the third terminal of the charging and discharging circuit, and the third terminal grounded. When the hot-swappable circuit is powered on, the first delay circuit is used to control the start time of discharge of the capacitor unit.

4. The hot-swappable circuit according to claim 3, characterized in that: The first delay circuit includes a fifth resistor, a sixth resistor, a seventh resistor, a third capacitor, and a first MOSFET; The first end of the fifth resistor is connected to the power input terminal, and the second end is connected to the gate of the first MOS transistor. The first end of the sixth resistor is connected to the power input terminal, and the second end is connected to the drain of the first MOS transistor. The first end of the seventh resistor is connected to the second end of the fifth resistor, and the second end is connected to the source of the first MOS transistor. The first terminal of the third capacitor is connected to the gate of the first MOS transistor, and the second terminal is connected to the source of the first MOS transistor and grounded.

5. The hot-swappable circuit according to claim 2, characterized in that: The transistor is an NPN type transistor.

6. The hot-swappable circuit according to claim 1, characterized in that: The relay is a normally closed relay.

7. The hot-swappable circuit according to claim 1, characterized in that: The capacitor unit is a first capacitor, with its first end connected to the drain of the first MOS transistor and its second end connected to the gate of the first MOS transistor.

8. An electronic device, characterized in that, Includes the hot-swap circuit as described in any one of claims 1 to 7.

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