Hot plug circuit

Abstract

The utility model provides a hot plug circuit. The hot plug circuit comprises an input unit, a switch unit, a switch control unit, a discharge unit and an output unit, the switch unit comprises an MOS tube, a first capacitor and a first resistor, the first capacitor and the first resistor are connected with a grid electrode and a source electrode of the MOS tube in parallel, the switch control unit comprises a first triode, a first control circuit and a second control circuit, and the discharge unit comprises a second triode and a discharge circuit connected with the second triode; the input unit is connected with the first resistor, the first capacitor, the source electrode and the input end of the control circuit through the discharge unit. The grid is connected with the collector of the first triode, and the drain is connected with the output unit; after power-on for a first preset time, the first control circuit controls the first triode to be switched on, under the action of the second control circuit and the first resistor, the grid voltage is reduced to a first voltage threshold, the MOS tube is switched on, and an electric signal is provided for the output unit; and during power failure, the second triode is conducted, and residual electric signals are discharged through the discharge circuit. According to the scheme, the stability of the hot plug circuit is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of circuit design, and in particular to a hot-swap circuit. Background Art

[0002] A hot-swap circuit is an operation that allows a unit or load in a circuit system to be plugged in or out while the circuit system is operating normally, without affecting the components in the circuit system. Therefore, how to set up a safe and stable hot-swap circuit is an urgent problem to be solved. Utility Model Content

[0003] An embodiment of the present application provides a hot-swap circuit to improve the safety and stability of the hot-swap circuit.

[0004] In a first aspect, an embodiment of the present application provides a hot-swap circuit, comprising an input unit, a switch unit, a switch control unit, a discharge unit, and an output unit; the switch unit comprises a MOS tube, and a first capacitor and a first resistor connected in parallel with a gate and a source of the MOS tube; the switch control unit comprises a first triode, a first control circuit connected to a base of the first triode, and a second control circuit connected to an emitter of the first triode; the discharge unit comprises a second triode, and a discharge circuit connected to the second triode;

[0005] The input unit is connected to the first resistor, the first capacitor, the source of the MOS tube, the input end of the first control circuit and the input end of the second control circuit respectively through the discharge unit; the gate of the MOS tube is connected to the collector of the first transistor, and the drain of the MOS tube is connected to the output unit;

[0006] When the input unit is powered on, under the action of the first control circuit, the first transistor is turned off, under the action of the first capacitor, the gate voltage of the MOS transistor is at a first voltage value, the first voltage value is greater than a first voltage threshold, and after a first preset time, the first control circuit controls the first transistor to be turned on, under the action of the second control circuit and the first resistor, the gate voltage of the MOS transistor is reduced from the first voltage value to the first voltage threshold, the MOS transistor is turned on, and the drain of the MOS transistor provides an electrical signal to the output unit;

[0007] When the input unit is powered off, the second transistor is turned on, and the remaining electrical signal in the circuit is discharged through the discharge circuit.

[0008] Optionally, the first control circuit includes a second capacitor, a diode, a second resistor and a third resistor.

[0009] A first end of the second resistor is connected to the input unit via the discharge unit, a second end is connected to a first end of the third resistor, and a second end of the third resistor is grounded;

[0010] The second capacitor is connected in parallel with the third resistor;

[0011] The diode is connected in parallel with the second resistor, wherein the cathode of the diode is connected to the first end of the second resistor, and the anode of the diode is connected to the second end of the second resistor;

[0012] The second end of the second resistor is connected to the base of the first transistor;

[0013] Wherein, when the input unit is powered on, under the action of the second capacitor, the base voltage of the first transistor is at a second voltage value, the second voltage value is less than a second voltage threshold, and after a first preset time, the base voltage of the first transistor increases from the second voltage to the second voltage threshold, and the first transistor is turned on;

[0014] Furthermore, when the input unit is powered off, the remaining electrical signal in the second capacitor is transmitted to the discharge unit through the diode for discharge.

[0015] Optionally, the second control circuit includes a fourth resistor and a fifth resistor;

[0016] A first end of the fourth resistor is connected to the input unit via the discharge unit, a second end is connected to a first end of the fifth resistor, and a second end of the fifth resistor is grounded;

[0017] The second end of the fourth resistor is connected to the emitter of the first transistor;

[0018] Wherein, when the input unit is powered on, the emitter voltage of the first transistor is at a third voltage value, the third voltage value is greater than the second voltage value, and after a first preset time, the first transistor is turned on, under the action of the first resistor and the fourth resistor, the emitter voltage of the first transistor increases from the third voltage value to greater than the base voltage of the first transistor, and the first transistor is controlled to be turned off, under the action of the first capacitor, the gate voltage of the MOS tube decreases, and under the action of the second capacitor, the base voltage of the first transistor increases to greater than the emitter voltage of the first transistor, and the first transistor is controlled to be turned on, and the step of "the emitter voltage of the first transistor increases from the third voltage value to greater than the base voltage of the first transistor" is returned to continue to be executed until the base voltage of the first transistor is at a fourth voltage value, the fourth voltage value is determined based on the resistance values ​​of the second resistor and the third resistor, the resistance ratio of the second resistor to the third resistor is less than the resistance ratio of the fourth resistor to the fifth resistor, the first transistor is turned on, the gate voltage of the MOS tube decreases to the first voltage threshold, and the MOS tube is turned on.

[0019] Optionally, the discharge circuit includes a Schottky diode, a sixth resistor and a seventh resistor;

[0020] The anode of the Schottky diode is connected to the input unit, and the cathode is respectively connected to the first resistor, the first capacitor, the source of the MOS tube, the input end of the first control circuit, and the input end of the second control circuit;

[0021] A first end of the sixth resistor is respectively connected to the input unit, the anode of the Schottky diode and the base of the second transistor, and a second end is grounded;

[0022] The first end of the seventh resistor is connected to the cathode of the Schottky diode, and the second end is connected to the emitter of the second transistor;

[0023] The collector of the second transistor is grounded;

[0024] When the input unit is powered off, the base voltage of the second transistor is less than a third threshold, the second transistor is turned on, and the remaining electrical signal in the circuit is discharged through the seventh resistor and the second transistor.

[0025] Optionally, the input unit includes a power supply, a switch, and a transient voltage suppression diode;

[0026] The cathode of the transient voltage suppression diode is connected to the power supply, and the anode is grounded;

[0027] The switch is connected to the power supply, and when the switch is closed, the power supply is powered on, and when the switch is opened, the input unit is powered off.

[0028] Optionally, the output unit includes a polarity capacitor, a third capacitor and an output terminal;

[0029] The anode of the polar capacitor is connected to the drain of the MOS tube and the output end, and the cathode is grounded;

[0030] The third capacitor is connected in parallel with the polarity capacitor;

[0031] The output end is used to connect to a load to be connected.

[0032] Optionally, the output unit further includes a fuse device;

[0033] The drain of the MOS tube and the anode of the polarity capacitor are connected to the output end via the fuse device.

[0034] The hot-swap circuit provided in the embodiment of the present application is provided with a switch unit and a switch control unit, wherein the switch unit includes a MOS tube and a first resistor and a first capacitor connected in parallel with the gate and source of the MOS tube, and the switch control unit includes a first triode and a first control circuit connected to the base of the first triode and a second control circuit connected to the emitter of the first triode, so that at the moment of power-on, under the action of the first control circuit, the first triode is turned off, and under the action of the first capacitor, the gate voltage of the MOS tube is greater than the voltage threshold when it is turned on, that is, the first voltage threshold, the MOS tube is not turned on, and the electrical signal cannot be transmitted to the output unit, so as to avoid damage to the connected load or unit at the moment of power-on, and at the moment of charging the first capacitor, the first triode is turned off, and the first capacitor is charged. Under the action of electricity, the gate voltage of the MOS tube decreases; and after a first preset time, the first control circuit controls the first triode to be turned on, and the second control circuit and the first resistor control the first triode to be turned off, the first capacitor continues to charge, and the gate voltage of the MOS tube continues to decrease until it decreases to the first voltage threshold. The MOS tube is turned on and can provide an electrical signal to the output unit, thereby delaying the power-on time of the output unit and further avoiding damage to the connected load or unit; when the power is off, the second triode is turned on, and the discharge circuit discharges the remaining electrical signal in the circuit to avoid damage to the circuit components by the remaining electrical signal in the circuit after the power is off, thereby realizing the setting of the hot-swap circuit and improving the safety and stability of the hot-swap circuit access system.

[0035] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic diagram of an embodiment of a hot swap circuit provided by the present application is shown. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0039] In some structures described in the specification and claims of this application and the above drawings, multiple structural parts appearing in a specific order are included, and the serial numbers of these structural parts, such as 101, 102, etc., are only used to distinguish different structural parts. It should be noted that the descriptions of "first", "second", etc. in this article are used to distinguish different structural parts, etc., and do not represent the order of precedence, nor do they limit the "first" and "second" to be different types.

[0040] The embodiments of the present application can be applied to the field of circuit design, and in particular to hot-swap circuit design. A hot-swap circuit is an operation in which a unit or load of a circuit system is plugged in or out while the circuit system is operating normally, without affecting the components in the circuit system. Therefore, how to set up a safe and stable hot-swap circuit is an urgent problem to be solved.

[0041] Based on this, the inventors proposed the technical solution of the present application, including an input unit, a switch unit, a switch control unit, a discharge unit, and an output unit; the switch unit includes a MOS tube, and a first capacitor and a first resistor connected in parallel with the gate and source of the MOS tube; the switch control unit includes a first triode, a first control circuit connected to the base of the first triode, and a second control circuit connected to the emitter of the first triode; the discharge unit includes a second triode, and a discharge circuit connected to the second triode; the input unit is respectively connected to the first resistor, the first capacitor, the source of the MOS tube, the input end of the first control circuit, and the input end of the second control circuit through the discharge unit; The gate of the MOS tube is connected to the collector of the first triode, and the drain of the MOS tube is connected to the output unit; when the input unit is powered on, under the action of the first capacitor, the gate voltage of the MOS tube is at a first voltage value, the first voltage value is greater than a first voltage threshold, and after a first preset time, the first control circuit controls the first triode to be turned on, and under the action of the second control circuit and the first resistor, the gate voltage of the MOS tube is reduced from the first voltage value to the first voltage threshold, the MOS tube is turned on, and the drain of the MOS tube provides an electrical signal to the output unit; when the input unit is powered off, the second triode is turned on, and the remaining electrical signal in the circuit is discharged through the discharge circuit.

[0042] The technical solution of the present application is to set a switch unit and a switch control unit, wherein the switch unit includes a MOS tube and a first resistor and a first capacitor connected in parallel with the gate and source of the MOS tube, and the switch control unit includes a first triode and a first control circuit connected to the base of the first triode and a second control circuit connected to the emitter of the first triode. It can be achieved that at the moment of power-on, under the action of the first control circuit, the first triode is turned off, and under the action of the first capacitor, the gate voltage of the MOS tube is greater than the voltage threshold when it is turned on, that is, the first voltage threshold, the MOS tube is not turned on, and the electrical signal cannot be transmitted to the output unit, thereby avoiding damage to the connected load or unit at the moment of power-on, and under the action of the charging of the first capacitor, the first triode is turned off. Under the condition that the gate voltage of the MOS tube decreases; and after a first preset time, the first control circuit controls the first triode to be turned on, and the second control circuit and the first resistor control the first triode to be turned off, the first capacitor continues to charge, and the gate voltage of the MOS tube continues to decrease until it decreases to the first voltage threshold, the MOS tube is turned on, and an electrical signal can be provided to the output unit, thereby delaying the power-on time of the output unit, and further avoiding damage to the connected load or unit; when the power is off, the second triode is turned on, and the discharge circuit discharges the remaining electrical signal in the circuit, avoiding damage to the circuit components by the remaining electrical signal in the circuit after the power is off, thereby realizing the setting of the hot-swap circuit and improving the safety and stability of the hot-swap circuit access system.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0044] like Figure 1 As shown, it is a structural schematic diagram of an embodiment of a hot-swap circuit provided by the present application, which may include an input unit, a switch unit, a switch control unit, a discharge unit, and an output unit.

[0045] The switch unit may include a MOS transistor Q1 , and a first capacitor C1 and a first resistor R1 connected in parallel with a gate and a source of the MOS transistor Q1 .

[0046] The switch control unit may include a first transistor Q2, a first control circuit connected to the base of the first transistor Q2, and a second control circuit connected to the emitter of the first transistor Q2.

[0047] The discharge unit may include a second transistor Q3 and a discharge circuit connected to the second transistor Q3.

[0048] Specifically, the input unit can be connected to the first resistor R1, the first capacitor C1, the source of the MOS tube Q1, the input end of the first control circuit and the input end of the second control circuit respectively through the discharge unit; the gate of the MOS tube Q1 can be connected to the collector of the first transistor Q2, and the drain of the MOS tube Q1 is connected to the output unit.

[0049] When the input unit is powered on, under the action of the first control circuit, the first transistor Q2 is turned off, under the action of the first capacitor C1, the gate voltage of the MOS transistor Q1 is at a first voltage value, the first voltage value is greater than the first voltage threshold, and after a first preset time, the first control circuit controls the first transistor Q2 to be turned on, under the action of the second control circuit and the first resistor R1, the gate voltage of the MOS transistor Q1 is reduced from the first voltage value to the first voltage threshold, the MOS transistor Q1 is turned on, and the drain of the MOS transistor Q1 provides an electrical signal to the output unit.

[0050] Furthermore, when the input unit is powered off, the second transistor Q3 is turned on, and the remaining electrical signal in the circuit can be discharged through the discharge circuit.

[0051] In the solution of the present application, the MOS tube Q1 adopts a P-channel MOS tube, the first transistor Q2 adopts an NPN transistor, and the second transistor Q3 adopts a PNP transistor. Of course, an N-channel MOS tube can also be used, which can be set according to actual needs and circuit connections.

[0052] In this embodiment, at the moment when the input unit is powered on, under the action of the first control circuit, the first triode Q2 is turned off, and under the action of the first capacitor C1, the gate voltage of the MOS tube Q1 is at a first voltage value, which is higher than the threshold voltage when the MOS tube Q1 is turned on, that is, the first voltage threshold. At this time, the MOS tube Q1 is not turned on, and the electrical signal cannot be transmitted to the output unit through the drain of the MOS tube Q1. At the same time, the first capacitor C1 is charged.

[0053] After the first preset time, the first control circuit controls the first transistor Q2 to be turned on, the charging of the first capacitor C1 is interrupted, and when the gate voltage of the MOS tube Q1 has not yet decreased to the first voltage threshold, the MOS tube Q1 is still not turned on, and the electrical signal cannot be transmitted to the output unit through the drain of the MOS tube Q1.

[0054] Under the action of the first control circuit and the first resistor R1, the first transistor Q2 is controlled to be turned off, the first capacitor C1 continues to be charged, and the gate voltage of the MOS tube Q1 continues to decrease until it decreases to the first voltage threshold. The MOS tube Q1 is turned on, and the electrical signal can be transmitted to the output unit through the drain of the MOS tube Q1, thereby delaying the power-on time of the output unit to avoid damage to the connected load or unit.

[0055] When the input unit is powered off, the second transistor Q3 is turned on, and the remaining electrical signal in the circuit can be discharged through the discharge unit.

[0056] It is understandable that, by setting the first capacitor, it is possible to avoid the input unit triggering overcurrent protection due to the large capacitor charging current at the moment the MOS tube is turned on due to the large capacitance at the load end. At the same time, the stability of the MOS tube operating environment can be improved.

[0057] By setting a switch unit and a switch control unit, wherein the switch unit includes a MOS tube and a first resistor and a first capacitor connected in parallel with the gate and source of the MOS tube, and the switch control unit includes a first triode and a first control circuit connected to the base of the first triode and a second control circuit connected to the emitter of the first triode, it can be achieved that at the moment of power-on, under the action of the first control circuit, the first triode is turned off, and under the action of the first capacitor, the gate voltage of the MOS tube is greater than the voltage threshold when it is turned on, that is, the first voltage threshold, the MOS tube is not turned on, and the electrical signal cannot be transmitted to the output unit, thereby avoiding damage to the connected load or unit at the moment of power-on, and under the charging action of the first capacitor, the MOS The gate voltage of the MOS tube decreases; and after a first preset time, the first control circuit controls the first triode to be turned on, and the second control circuit and the first resistor control the first triode to be turned off, the first capacitor continues to charge, and the gate voltage of the MOS tube continues to decrease until it decreases to a first voltage threshold, the MOS tube is turned on, and an electrical signal can be provided to the output unit, thereby delaying the power-on time of the output unit, and further avoiding damage to the connected load or unit; when the power is off, the second triode is turned on, and the discharge circuit discharges the remaining electrical signal in the circuit, avoiding damage to the circuit components by the remaining electrical signal in the circuit after the power is off, thereby realizing the setting of the hot-swap circuit and improving the safety and stability of the hot-swap circuit access system.

[0058] The implementation of the control circuit is described below.

[0059] In some embodiments, the first control circuit may include a second capacitor C2, a diode Q4, a second resistor R2, and a third resistor R3.

[0060] The first end of the second resistor R2 is connected to the input unit via the discharge unit, the second end is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is grounded.

[0061] The second capacitor C2 is connected in parallel with the third resistor R3.

[0062] The diode Q4 is connected in parallel with the second resistor R2 , wherein the cathode of the diode Q4 is connected to the first end of the second resistor R2 , and the anode of the diode Q4 is connected to the second end of the second resistor R2 .

[0063] The second end of the second resistor R2 is connected to the base of the first transistor Q2.

[0064] Among them, when the input unit is powered on, under the action of the second capacitor C2, the base voltage of the first transistor Q2 is at a second voltage value, the second voltage value is less than the second voltage threshold, and after the first preset time, the base voltage of the first transistor Q2 increases from the second voltage to the second voltage threshold, and the first transistor Q2 is turned on.

[0065] Furthermore, when the input unit is powered off, the remaining electrical signal in the second capacitor C2 is transmitted to the discharge unit via the diode Q4 for discharge.

[0066] In this embodiment, at the moment when the input unit is powered on, combined with the characteristic that the voltage across the capacitor will not suddenly change, under the action of the second capacitor C2, the base voltage of the first diode Q2 is less than the voltage threshold when it is turned on, that is, the second voltage threshold, and the first transistor Q2 is not turned on. At the same time, the second capacitor C2 is charged.

[0067] It can be understood that the base voltage rising time of the first transistor Q2 can be controlled by adjusting the parameters of the second resistor R2 and the second capacitor C2. That is to say, the conduction time of the first transistor Q2 is determined by the second resistor R2 and the second capacitor C2 and can be set according to actual needs.

[0068] After the first preset time, the base voltage of the first transistor Q2 increases until it increases to a second voltage threshold, and the first transistor Q2 is turned on.

[0069] By setting the second capacitor, the conduction time of the first transistor is delayed to avoid damage to the first transistor at the moment of power-on, and the conduction time of the MOS tube is further delayed, thereby enhancing the delay effect of the power-on time of the output unit and enhancing the safety and stability of the hot-swap circuit.

[0070] It is understandable that the first control circuit may also have other implementations, such as using other devices with resistance values, other devices that delay the start-up of the first transistor, etc., which can be set according to actual needs.

[0071] In some embodiments, the second control circuit may include a fourth resistor R4 and a fifth resistor R5.

[0072] The first end of the fourth resistor R4 is connected to the input unit via the discharge unit, the second end is connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is grounded.

[0073] The second end of the fourth resistor R4 is connected to the emitter of the first transistor Q2.

[0074] When the input unit is powered on, the emitter voltage of the first triode Q2 is at a third voltage value, the third voltage value is greater than the second voltage value, and after the first preset time, the first triode Q2 is turned on, and under the action of the first resistor R1 and the fourth resistor R4, the emitter voltage of the first triode Q2 increases from the third voltage value to a value greater than the base voltage of the first triode Q2, and the first triode Q2 is controlled to be turned off, and under the action of the first capacitor C1, the gate voltage of the MOS tube Q1 is reduced, and under the action of the second capacitor C2, the base voltage of the first triode Q2 is increased to a value greater than the first triode. The emitter voltage of the MOS tube Q2 is increased to control the first triode Q2 to be turned on, and the step of "the emitter voltage of the first triode Q2 is increased from the third voltage value to be greater than the base voltage of the first triode Q2" is returned to continue to be executed until the base voltage of the first triode Q2 is at a fourth voltage value, the fourth voltage value is determined based on the resistance values ​​of the second resistor R2 and the third resistor R3, the resistance ratio of the second resistor R2 to the third resistor R3 is less than the resistance ratio of the fourth resistor R4 to the fifth resistor R5, the first triode Q2 is turned on, the gate voltage of the MOS tube Q1 is reduced to the first voltage threshold, and the MOS tube is turned on.

[0075] In this embodiment, since the resistance values ​​of the fourth resistor R4 and the fifth resistor R5 are fixed, at the moment of power-on, the voltage division of the two is fixed, and the emitter voltage of the first triode Q2 is at a fixed third voltage value. After the first preset time, the first triode Q2 is turned on, and ignoring the resistance value of the first triode Q2, the first resistor R1 is connected in parallel with the fourth resistor R4, and the emitter voltage of the first triode Q2 increases. When it increases to a value greater than the base voltage of the first triode Q2, the first triode Q2 is controlled to be turned off. At this time, under the action of the first capacitor C1, the gate voltage of the MOS tube Q1 continues to decrease, and under the action of the second capacitor C2, the base voltage of the first triode Q2 continues to increase until it increases to a value greater than the emitter voltage, and the first triode Q2 is controlled to continue to be turned on. This cycle is repeated until the base voltage of the first transistor Q2 is at a fixed fourth voltage value, which is determined by the voltage division of the second resistor R2 and the third resistor R3, wherein the resistance ratio of the second resistor R2 to the third resistor R3 can be set to be smaller than the resistance ratio of the fourth resistor R4 to the fifth resistor R5. Therefore, when the base voltage of the first transistor Q2 reaches the fourth voltage value, it is greater than the emitter voltage, and the MOS maintains the on state.

[0076] In the above process, under the action of the first capacitor C1, the gate voltage of the MOS tube Q1 decreases when the first transistor Q2 is turned off until it decreases to the first voltage threshold, and the MOS tube is turned on to provide an electrical signal to the output unit to achieve power-on time delay.

[0077] By setting the second control circuit, the first control circuit and the first resistor are combined to control the first transistor to be turned on and off, so as to reduce the gate voltage of the MOS tube to the first voltage threshold, thereby realizing power-on delay.

[0078] It is understandable that the second control circuit may also have other implementations, such as using other devices with resistance values, or sliding resistors, etc. for voltage division, which can be set according to actual needs.

[0079] In some embodiments, the discharge circuit may include a Schottky diode Q4 , a sixth resistor R6 , and a seventh resistor R7 .

[0080] The anode of the Schottky diode Q4 is connected to the input unit, and the cathode is respectively connected to the first resistor R1, the first capacitor C1, the source of the MOS transistor Q1, the input end of the first control circuit and the input end of the second control circuit.

[0081] A first end of the sixth resistor R6 is respectively connected to the input unit, the anode of the Schottky diode Q4 and the base of the second transistor Q3 , and a second end thereof is grounded.

[0082] A first end of the seventh resistor R7 is connected to the cathode of the Schottky diode Q4 , and a second end of the seventh resistor R7 is connected to the emitter of the second transistor Q3 .

[0083] The collector of the second transistor Q3 is grounded.

[0084] When the input unit is powered off, the base voltage of the second transistor Q3 is less than the third voltage threshold, the second transistor Q3 is turned on, and the remaining electrical signal in the circuit is discharged through the seventh resistor R7 and the second transistor Q3.

[0085] To reduce power loss, a Schottky diode with a smaller forward voltage drop can be selected.

[0086] By setting a Schottky diode, the reverse transmission of the electrical signal of the capacitive load after power failure can be avoided, thereby preventing damage to the input unit, etc., thereby improving the safety and stability of the hot-swap circuit.

[0087] In some embodiments, the input unit may include a power supply VCC_IN, a switch (not shown), and a transient voltage suppressor diode Q5.

[0088] The cathode of the transient voltage suppression diode Q5 is connected to the power supply VCC_IN, and the anode is grounded.

[0089] The switch is connected to the power supply VCC_IN. When the switch is closed, the input unit is powered on, and when the switch is opened, the input unit is powered off.

[0090] By setting up a transient voltage suppression diode, large surge current in the circuit can be avoided to damage the circuit, further improving the safety and stability of the hot-swap circuit.

[0091] In some embodiments, the output unit may include a polarity capacitor C3, a third capacitor C4, and an output terminal VCC_OUT.

[0092] The anode of the polarity capacitor C3 is connected to the drain and the output end of the MOS tube Q1 , and the cathode is grounded.

[0093] The third capacitor C4 is connected in parallel with the polarity capacitor C3.

[0094] The output terminal VCC_OUT is used to connect to the load to be connected.

[0095] In some embodiments, the output unit may further include a fuse device FU.

[0096] The drain of the MOS tube Q1 and the anode of the polarity capacitor C3 are connected to the output end via the fuse device FU.

[0097] By providing a polarity capacitor and a third capacitor in parallel, as well as a fuse, the safety and stability of the hot-swap circuit connected to a load or unit are further improved.

[0098] The present application also provides a circuit, which may include Figure 1 The hot-swap circuit and the load to be connected are shown, wherein the load to be connected can be connected to the output end of the output unit of the hot-swap circuit, which will not be described in detail.

[0099] It is clear to those skilled in the art that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative labor.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A hot-swap circuit, characterized in that: The invention comprises an input unit, a switch unit, a switch control unit, a discharge unit, and an output unit; the switch unit comprises a MOS tube, and a first capacitor and a first resistor connected in parallel with the gate and source of the MOS tube; the switch control unit comprises a first triode, a first control circuit connected to the base of the first triode, and a second control circuit connected to the emitter of the first triode; the discharge unit comprises a second triode, and a discharge circuit connected to the second triode; The input unit is connected to the first resistor, the first capacitor, the source of the MOS tube, the input end of the first control circuit and the input end of the second control circuit respectively through the discharge unit; the gate of the MOS tube is connected to the collector of the first transistor, and the drain of the MOS tube is connected to the output unit; When the input unit is powered on, under the action of the first control circuit, the first transistor is turned off, under the action of the first capacitor, the gate voltage of the MOS transistor is at a first voltage value, the first voltage value is greater than a first voltage threshold, and after a first preset time, the first control circuit controls the first transistor to be turned on, under the action of the second control circuit and the first resistor, the gate voltage of the MOS transistor is reduced from the first voltage value to the first voltage threshold, the MOS transistor is turned on, and the drain of the MOS transistor provides an electrical signal to the output unit; When the input unit is powered off, the second transistor is turned on, and the remaining electrical signal in the circuit is discharged through the discharge circuit.

2. The circuit according to claim 1, characterized in that The first control circuit includes a second capacitor, a diode, a second resistor and a third resistor. A first end of the second resistor is connected to the input unit via the discharge unit, a second end is connected to a first end of the third resistor, and a second end of the third resistor is grounded; The second capacitor is connected in parallel with the third resistor; The diode is connected in parallel with the second resistor, wherein the cathode of the diode is connected to the first end of the second resistor, and the anode of the diode is connected to the second end of the second resistor; The second end of the second resistor is connected to the base of the first transistor; Wherein, when the input unit is powered on, under the action of the second capacitor, the base voltage of the first transistor is at a second voltage value, the second voltage value is less than a second voltage threshold, and after a first preset time, the base voltage of the first transistor increases from the second voltage to the second voltage threshold, and the first transistor is turned on; Furthermore, when the input unit is powered off, the remaining electrical signal in the second capacitor is transmitted to the discharge unit through the diode for discharge.

3. The circuit according to claim 2, characterized in that The second control circuit includes a fourth resistor and a fifth resistor; A first end of the fourth resistor is connected to the input unit via the discharge unit, a second end is connected to a first end of the fifth resistor, and a second end of the fifth resistor is grounded; The second end of the fourth resistor is connected to the emitter of the first transistor; Wherein, when the input unit is powered on, the emitter voltage of the first transistor is at a third voltage value, the third voltage value is greater than the second voltage value, and after a first preset time, the first transistor is turned on, under the action of the first resistor and the fourth resistor, the emitter voltage of the first transistor increases from the third voltage value to greater than the base voltage of the first transistor, and the first transistor is controlled to be turned off, under the action of the first capacitor, the gate voltage of the MOS tube decreases, and under the action of the second capacitor, the base voltage of the first transistor increases to greater than the emitter voltage of the first transistor, and the first transistor is controlled to be turned on, and the step of "the emitter voltage of the first transistor increases from the third voltage value to greater than the base voltage of the first transistor" is returned to continue to be executed until the base voltage of the first transistor is at a fourth voltage value, the fourth voltage value is determined based on the resistance values ​​of the second resistor and the third resistor, the resistance ratio of the second resistor to the third resistor is less than the resistance ratio of the fourth resistor to the fifth resistor, the first transistor is turned on, the gate voltage of the MOS tube decreases to the first voltage threshold, and the MOS tube is turned on.

4. The circuit according to claim 3, characterized in that The discharge circuit includes a Schottky diode, a sixth resistor and a seventh resistor; The anode of the Schottky diode is connected to the input unit, and the cathode is respectively connected to the first resistor, the first capacitor, the source of the MOS tube, the input end of the first control circuit, and the input end of the second control circuit; A first end of the sixth resistor is respectively connected to the input unit, the anode of the Schottky diode and the base of the second transistor, and a second end is grounded; The first end of the seventh resistor is connected to the cathode of the Schottky diode, and the second end is connected to the emitter of the second transistor; The collector of the second transistor is grounded; When the input unit is powered off, the base voltage of the second transistor is less than a third threshold, the second transistor is turned on, and the remaining electrical signal in the circuit is discharged through the seventh resistor and the second transistor.

5. The circuit according to claim 1, characterized in that The input unit includes a power supply, a switch, and a transient voltage suppression diode; The cathode of the transient voltage suppression diode is connected to the power supply, and the anode is grounded; The switch is connected to the power supply, and when the switch is closed, the power supply is powered on, and when the switch is opened, the input unit is powered off.

6. The circuit according to claim 1, characterized in that The output unit includes a polarity capacitor, a third capacitor and an output terminal; The anode of the polar capacitor is connected to the drain of the MOS tube and the output end, and the cathode is grounded; The third capacitor is connected in parallel with the polarity capacitor; The output end is used to connect to a load to be connected.

7. The circuit according to claim 6, characterized in that The output unit also includes a fuse; The drain of the MOS tube and the anode of the polarity capacitor are connected to the output end via the fuse device.

Images