Gradual start protection circuit, integrated chip and control method

Abstract

The application provides a slow start protection circuit, an integrated chip and a control method, which comprise a charge pump, a soft start module and a power MOS tube; the charge pump is used for generating a bias current and inputting the bias current to the soft start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of a voltage output end; wherein the bias current comprises a first bias current and a second bias current; the soft start module is used for adjusting the gate voltage of the power MOS tube according to a preset reference voltage and the bias current, so that the output voltage changes at the change speed of the preset reference voltage. In this way, the output voltage is stably powered on according to the power-on waveform of the reference voltage by connecting the soft start module in front of the gate of the power MOS tube, and the stability of the circuit loop is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit protection, in particular to a soft-start protection circuit, an integrated chip and a control method. BACKGROUND

[0002] At present, in order to reduce the dropout voltage and reduce the loss, the application range of the large current output power supply type chip using N-type power tube is more and more wide, such as LDO (low dropout regulator), load switch and the like. In the process of starting, in order to reduce the influence of the impact current on the load, a low frequency pole is usually introduced at the gate of the power tube. When the gate parasitic capacitance of the power tube is large, the two poles are close in the frequency spectrum, which makes the loop stability worse and affects the stability of the soft-start circuit loop. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a soft-start protection circuit, an integrated chip and a control method, which can make the output voltage stable during power-on according to the power-on waveform of the reference voltage, and further improve the stability of the circuit loop.

[0004] In a first aspect, the present application provides a soft-start protection circuit, comprising: a charge pump, a soft-start module and a power MOS tube; the first end and the second end of the charge pump are connected with the soft-start module respectively; the second end of the charge pump is also connected with the gate of the power MOS tube; the drain of the power MOS tube is connected with a voltage input end, and the source is connected with a voltage output end; the charge pump is used to generate a bias current and input the bias current to the soft-start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output end; wherein the bias current comprises a first bias current and a second bias current; the soft-start module is used to adjust the gate voltage of the power MOS tube according to the preset reference voltage and the bias current, so that the output voltage changes according to the change speed of the preset reference voltage.

[0005] Further, the soft-start protection circuit further comprises a voltage feedback module, the voltage feedback module comprises a first resistor and a second resistor connected in series, the source of the power MOS tube is connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the second resistor and the soft-start module; the second end of the second resistor is grounded; the first resistor and the second resistor are used to generate a feedback voltage according to the voltage of the voltage output end, so as to send to the soft-start module.

[0006] Further, the soft-start protection circuit further comprises a voltage variation reference module; the soft-start module comprises a first MOS tube and a current mirror circuit; the charge pump is connected with the drain and the gate of the first MOS tube through a first branch of a first end, and is connected with a first end of the current mirror circuit through a second branch of the first end; the charge pump is connected with a second end of the current mirror circuit through a first branch of a second end, and is connected with the power MOS tube through a second branch of the second end; a source of the first MOS tube is connected with the voltage feedback module; the second end of the current mirror circuit is connected with the first branch of the second end of the charge pump, and a third end of the current mirror circuit is connected with one end of the voltage variation reference module; the other end of the voltage variation reference module is grounded; the voltage variation reference module is used for outputting a preset reference voltage to the current mirror circuit; the charge pump is further used for, when a potential of the feedback voltage is greater than a potential of the preset reference voltage, reducing a first MOS current output to the first MOS tube through the first end, increasing a first current mirror current output to the current mirror circuit, so as to enhance a driving capability of the current mirror circuit, increasing a second current mirror current output to the current mirror circuit through the second end, and reducing a second MOS current output to the gate of the power MOS tube, so as to reduce a variation speed of the output voltage; the charge pump is further used for, when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, enhancing the first MOS current output to the first MOS tube through the first end, reducing the first current mirror current output to the current mirror circuit, so as to enhance the driving capability of the current mirror circuit, reducing the second current mirror current output to the current mirror circuit through the second end, and enhancing the second MOS current output to the gate of the power MOS tube, so as to improve an output rate of the output voltage; wherein the first MOS current and the first current mirror current are first bias currents; and the second MOS current and the second current mirror current are second bias currents.

[0007] Further, the current mirror circuit comprises a second MOS tube and a third MOS tube; a gate of the second MOS tube is connected with a gate of the third MOS tube; a source of the second MOS tube and a source of the third MOS tube are connected with the voltage variation reference module; a drain of the second MOS tube is connected with the gate of the second MOS tube and a second branch of the first end of the charge pump; a drain of the third MOS tube is connected with a first branch of the second end of the charge pump; a width-length ratio of the second MOS tube and a width-length ratio of the third MOS tube are set according to a preset ratio; the second MOS tube is configured to increase the received first bias current when a potential of the feedback voltage is greater than a potential of the preset reference voltage, increase the source voltage of the second MOS tube, and make the third MOS tube enter a deep linear region; the second MOS tube is configured to decrease the received first bias current when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, decrease the source voltage of the second MOS tube, and make the third MOS tube enter the deep linear region; the third MOS tube is configured to increase the source voltage of the third MOS tube to increase the obtained second bias current when the potential of the feedback voltage is greater than the potential of the preset reference voltage; the third MOS tube is configured to decrease the source voltage of the third MOS tube to decrease the obtained second bias current when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage.

[0008] Further, the soft start module further comprises a third resistor; one end of the third resistor is connected with the first branch of the first end of the charge pump; the other end of the third resistor is connected with the first MOS tube; the third resistor is configured to generate an input offset current when the reference voltage is 0, so that the first bias current flows into the current mirror circuit.

[0009] Further, the soft start module further comprises a third resistor; one end of the third resistor is connected with the first branch of the first end of the charge pump; the other end of the third resistor is connected with the first MOS tube; the third resistor is configured to generate an input offset current when the reference voltage is 0, so that the first bias current flows into the current mirror circuit.

[0010] Further, the soft start module comprises a diode; the diode is connected with the current mirror circuit and the gate of the power MOS tube respectively; the diode is configured to prevent the current from flowing back to the parasitic capacitor when the current output by the current mirror circuit is too high.

[0011] In a second aspect, an embodiment of the present application provides a soft start protection integrated chip, comprising a body, and further comprising the soft start protection circuit according to any one of the above, and the soft start protection circuit is arranged on the body.

[0012] In a third aspect, the embodiments of the present application provide a control method of the soft-start protection circuit, characterized in being used for controlling any one of the soft-start protection circuits; the method comprises: generating a bias current by the charge pump; inputting the bias current to the soft-start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output terminal; adjusting the gate voltage of the power MOS tube by the soft-start module according to the preset reference voltage and the bias current, so that the output voltage changes at the change speed of the preset reference voltage.

[0013] In a fourth aspect, the embodiments of the present application provide an electronic device, comprising a memory and a processor, wherein the memory stores a computer program capable of running on the processor, and the processor implements the method described above when executing the computer program.

[0014] The embodiments of the present application provide a soft-start protection circuit, an integrated chip and a control method, comprising: a charge pump, a soft-start module and a power MOS tube; the first end and the second end of the charge pump are connected with the soft-start module respectively; the second end of the charge pump is also connected with the gate of the power MOS tube; the drain of the power MOS tube is connected with a voltage input terminal, and the source is connected with a voltage output terminal; the charge pump is used for generating a bias current and inputting the bias current to the soft-start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output terminal; wherein the bias current comprises a first bias current and a second bias current; the soft-start module is used for adjusting the gate voltage of the power MOS tube according to the preset reference voltage and the bias current, so that the output voltage changes at the change speed of the preset reference voltage. In this way, by connecting the soft-start module in front of the gate of the power MOS tube, the output voltage is stably powered according to the power-on waveform of the reference voltage, and the stability of the circuit loop is improved.

[0015] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and attained by the structure particularly pointed out in the description and claims hereof as well as the appended drawings.

[0016] In order to make the above objectives, characteristics and advantages of the present application more apparent, the following will describe a preferred embodiment, and the accompanying drawings will be described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0018] Figure 1 The slow start protection circuit schematic diagram provided for the embodiment one of the present application;

[0019] Figure 2 Another slow start protection circuit schematic diagram provided for the embodiment one of the present application;

[0020] Figure 3 The reference voltage change schematic diagram provided for the embodiment one of the present application;

[0021] Figure 4 The slow start protection integrated chip schematic diagram provided for the embodiment two of the present application;

[0022] Figure 5 The control method flow chart of the slow start protection circuit provided for the embodiment three of the present application.

[0023] Figure legend: 1-charge pump; 2-soft start module; 3-power MOS tube; 4-voltage feedback module; 5-voltage change reference module; 6-parasitic capacitor; 7-slow start protection integrated chip; 8-slow start protection circuit. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0025] The conventional architecture generally adopts common source structure at the gate of the power MOS tube. When the output end of the MOS tube is connected with a large capacitor or inductor load, the input voltage rises too fast to output a large current, which may damage the load connected with the output end. Therefore, the embodiments of the present application provide a circuit structure to stabilize the output voltage of the MOS tube during power-on.

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] Embodiment one:

[0028] Figure 1 The slow start protection circuit schematic diagram provided for the embodiment one of the present application;

[0029] Figure 2 Another slow start protection circuit schematic diagram provided for the embodiment one of the present application;

[0030] Reference Figure 1The soft-start protection circuit comprises: a charge pump 1, a soft-start module 2 and a power MOS tube 3.

[0031] With reference to Figure 2 The first end and the second end of the charge pump are connected to the soft-start module respectively; the second end of the charge pump is also connected to the gate of the power MOS tube; the drain of the power MOS tube is connected to the voltage input end, and the source is connected to the voltage output end.

[0032] Here, the voltage of the charge pump chargepump is V out +VDD, and the VDD voltage is determined by an internal LDO.

[0033] The charge pump is used to generate a bias current and input the bias current to the soft-start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output end; wherein the bias current comprises a first bias current and a second bias current.

[0034] Here, the first end of the charge pump chargepump outputs the first bias current Ibias1, and the second end of the charge pump outputs the second bias current Ibias2, wherein the sizes of Ibias1 and Ibias2 can be the same or different.

[0035] The soft-start module is used to adjust the gate voltage of the power MOS tube according to the preset reference voltage and the bias current, so that the output voltage changes at the change speed of the preset reference voltage.

[0036] Here, the power MOS tube MP adopts an N-type MOS tube, and compared with a P-type MOS tube, the area of the N-type MOS tube is smaller when satisfying the same on-resistance. Wherein, the gate voltage of MP is V gate , the drain of MP is connected to the voltage input end V in , and the source is connected to the voltage output end V out .

[0037] In an embodiment, with reference to Figure 1 The soft-start protection circuit further comprises a voltage feedback module 4.

[0038] With reference to Figure 2 The voltage feedback module comprises a first resistor and a second resistor connected in series, the source of the power MOS tube is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the second resistor and the soft-start module; and the second end of the second resistor is grounded.

[0039] The first resistor and the second resistor are used to generate a feedback voltage according to the output voltage of the voltage output end, so as to send to the soft-start module.

[0040] Here, the feedback coefficient of the first resistor R1 and the second resistor R2 is The feedback voltage generated by the voltage feedback module is VFB.

[0041] In an embodiment, with reference to Figure 1 , the soft start module further comprises a voltage variation reference module 5.

[0042] With reference to Figure 2 , the soft start module comprises a first MOS transistor and a current mirror circuit; the charge pump is connected to the drain and the gate of the first MOS transistor through a first branch of a first end, and is connected to a first end of the current mirror circuit through a second branch of the first end; the charge pump is connected to a second end of the current mirror circuit through a first branch of a second end, and is connected to the power MOS transistor through a second branch of the second end; the source of the first MOS transistor is connected to the voltage feedback module; the second end of the current mirror circuit is connected to the first branch of the second end of the charge pump, and the third end of the current mirror circuit is connected to one end of the voltage variation reference module; the other end of the voltage variation reference module is grounded.

[0043] The voltage variation reference module is configured to output a preset reference voltage to the current mirror circuit.

[0044] Here, the voltage variation reference module dv / dt_vref can be given internally in the circuit or set by the user. The voltage variation module provides a reference voltage for the soft start protection circuit, so that the output voltage V out The change speed of the reference voltage can be changed according to the change speed of the reference voltage output by the voltage variation reference module. With reference to Figure 3 , the horizontal axis is time, and the vertical axis is the reference voltage value output by the voltage variation reference module, Figure 3 The slope of the reference voltage is the change speed of the reference voltage.

[0045] The charge pump is further configured to, when the potential of the feedback voltage is greater than the potential of the preset reference voltage, decrease the current output by the first branch of the first end of the charge pump, i.e., the current flowing through the first MOS transistor is decreased, and since the first bias current Ibias1 is unchanged, the current output by the second branch of the second end of the charge pump is increased, i.e., the current output to the current mirror circuit is increased, so as to enhance the driving capability of the current mirror circuit. Through the current mirror effect, the current flowing through the first branch of the second end of the charge pump is increased, and since the second bias current Ibias2 is unchanged, the current of the second branch of the second end of the charge pump is decreased, so as to decrease the second MOS current output to the gate of the power MOS transistor, so as to decrease the change speed of the output voltage.

[0046] The charge pump is also used to increase the current output by the first branch of the first end of the charge pump, i.e. the current flowing through the first MOS tube, when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, and since the first bias current Ibias1 is unchanged, the current output by the second branch of the second end of the charge pump is reduced, i.e. the current output to the current mirror circuit is reduced, so as to reduce the driving capability of the current mirror circuit, and through the current mirror effect, the current flowing through the first branch of the second end of the charge pump is reduced, so as to increase the second MOS current output to the gate of the power MOS tube, thereby improving the change speed of the output voltage.

[0047] Here, the first bias current and the second bias current are fixed in size.

[0048] In an embodiment, referring to Figure 2 , the current mirror circuit comprises a second MOS tube and a third MOS tube; the gate of the second MOS tube is connected to the gate of the third MOS tube; the source of the second MOS tube and the source of the third MOS tube are connected to the voltage change reference module; the drain of the second MOS tube is connected to the gate of the second MOS tube and the second branch of the first end of the charge pump; the drain of the third MOS tube is connected to the first branch of the second end of the charge pump; and the width-length ratio of the second MOS tube and the width-length ratio of the third MOS tube are set according to a preset ratio.

[0049] Here, the second MOS tube M2 and the third MOS tube M3 are input pair tubes of the current mirror circuit, and the width-length ratio is 1:N, and in the case of setting 1:N as large as possible, M3 can enter the deep linear region, and after entering the deep linear region, the impedance of M3 is very small, and the loop is more stable.

[0050] The size of N depends on how deep M3 needs to be pressed into the deep linear region and when M3 is in the deep linear region, the part of Ibias1 obtained in M2 multiplied by N can make M3 obtain almost all of Ibias2, so that no current flows into MP.

[0051] The second MOS tube is used to increase the proportion of the received first bias current when the potential of the feedback voltage is greater than the potential of the preset reference voltage, and to pull up the source voltage of the second MOS tube; and to reduce the proportion of the received first bias current when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, and to reduce the source voltage of the second MOS tube.

[0052] The third MOS tube is used to increase the source voltage of the third MOS tube to increase the proportion of the obtained second bias current when the potential of the feedback voltage is greater than the potential of the preset reference voltage; and to reduce the source voltage of the third MOS tube to reduce the proportion of the obtained second bias current when the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage.

[0053] Specifically, when dv / dt_vref is lower than VFB, the driving ability of M3 is enhanced, and the MP gate is pulled down; when dv / dt_vref is higher than VFB, the driving ability of M3 is weakened, and the MP gate is charged by the constant Ibias2 above. By adjusting the width-length ratio 1:N of the current mirror M2 and M3, M3 is pressed into the deep linear region, and the deep linear region current is shown in formula (1):

[0054]

[0055] wherein, I D is the M3 drain current, V GS is the M3 gate-source voltage, V DS is the M3 drain-source voltage, V TH is the M3 gate threshold voltage, W is the gate width of M3, L is the gate length of M3, is the width-length ratio of the oxide layer of M3, C ox ox is the gate oxide layer capacitance per unit area of M3, μ n is the electron mobility, V GS -V TH is the overdrive voltage.

[0056] V DS is much smaller than V GS -V TH , the above formula can be converted into formula (2),

[0057]

[0058] Deriving ID and VDS on both sides of the equation respectively, formula (3) is obtained

[0059]

[0060] wherein, R DS is the drain-source resistance of M3.

[0061] Increasing Ibias1 can increase the overdrive voltage value of M2 and M3, and reduce the equivalent resistance R DS of M3 from the MP gate, so as to push the pole of the MP gate out of the band. At the same time, since M3 is in the deep linear region, the loop gain of the structure can be made very small.

[0062] In an embodiment, referring to Figure 2 , the soft start module further includes a third resistor; one end of the third resistor is connected with the first branch of the first end of the charge pump; the other end of the third resistor is connected with the first MOS tube.

[0063] The third resistor is used to generate an input offset current when the preset reference voltage is 0, so that the first bias current flows into the current mirror circuit.

[0064] Here, the third resistor R3 generates an input offset current I offset In the initial stage of soft start, when dv / dt_vref is 0, let Ibias1 flow most of the current into M2, increase the driving capability of M2 and M3, pull down the gate potential of MP, and reduce the power-up step.

[0065] In an embodiment, referring to Figure 1 and Figure 2 The soft start protection circuit further comprises a parasitic capacitor 6; one end of the parasitic capacitor is connected to the connecting line between the gate of the power MOS tube and the soft start module; and the other end of the parasitic capacitor is grounded.

[0066] Here, the parasitic capacitor Cg is a collection of the three capacitors in MP, including the gate-source capacitor Cgs, the gate-drain capacitor Cgd, and the drain-source capacitor Cds.

[0067] In an embodiment, referring to Figure 2 The soft start module further comprises a diode; the diode is connected to the current mirror circuit and the gate of the power MOS tube, respectively.

[0068] The diode is used to prevent the current from flowing back to the parasitic capacitor when the current output by the current mirror circuit is too high.

[0069] Here, the diode D1 prevents the current from flowing back through the body diode of M3 when dv / dt_vref is higher than the gate voltage of MP.

[0070] The embodiment of the present application provides a soft start protection circuit, which comprises a charge pump, a soft start module, and a power MOS tube; the first end and the second end of the charge pump are connected to the soft start module, respectively; the second end of the charge pump is further connected to the gate of the power MOS tube; the drain of the power MOS tube is connected to a voltage input end, and the source of the power MOS tube is connected to a voltage output end; the charge pump is used to generate a bias current and input the bias current to the soft start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output end; wherein the bias current comprises a first bias current and a second bias current; the soft start module is used to adjust the gate voltage of the power MOS tube according to a preset reference voltage and the bias current, so that the output voltage changes at the changing speed of the preset reference voltage. In this way, by connecting the soft start module in front of the gate of the power MOS tube, the output voltage is stably powered up according to the power-up waveform of the reference voltage, and the stability of the circuit loop is improved.

[0071] Embodiment two

[0072] Figure 4 The soft start protection integrated chip provided in the embodiment two of the present application is shown in the figure.

[0073] Reference Figure 4 The soft-start protection integrated chip 7 includes a body and the aforementioned soft-start protection circuit 8, which is disposed on the body.

[0074] This invention provides a soft-start protection integrated chip, including a main body and a soft-start protection circuit. The soft-start protection circuit includes a charge pump, a soft-start module, and a power MOSFET. A first terminal and a second terminal of the charge pump are respectively connected to the soft-start module. The second terminal of the charge pump is also connected to the gate of the power MOSFET. The drain of the power MOSFET is connected to the voltage input terminal, and the source is connected to the voltage output terminal. The charge pump generates a bias current and inputs this bias current to the soft-start module and the power MOSFET, so that the gate voltage of the power MOSFET is higher than the output voltage of the voltage output terminal. The bias current includes a first bias current and a second bias current. The soft-start module adjusts the gate voltage of the power MOSFET according to a preset reference voltage and the bias current, so that the output voltage changes at the rate of change of the preset reference voltage. In this method, the soft-start protection circuit ensures that the load connected to the soft-start protection chip can operate normally, thereby improving the stability of the circuit loop.

[0075] Example 3:

[0076] Figure 5 The flowchart shows the control method of the soft-start protection circuit provided in Embodiment 3 of the present invention.

[0077] Reference Figure 5 The control methods for the soft-start protection circuit include:

[0078] Step S101: A bias current is generated by a charge pump.

[0079] In step S102, a bias current is input to the soft-start module and the power MOSFET so that the gate voltage of the power MOSFET is higher than the output voltage of the voltage output terminal.

[0080] In step S103, the soft-start module adjusts the gate voltage of the power MOSFET gate according to the preset reference voltage and bias current, so that the output voltage changes at the same rate as the preset reference voltage.

[0081] Here, when dv / dt_vref is lower than VFB, most of the Ibias1 in the charge pump flows to the current mirror circuit. M1 is turned on less, the pull-down drive voltage of M2 increases, the current of Ibias2 from the charge pump obtained by M3 increases, the current of Ibias2 obtained by MP decreases, and the gate of MP is pulled down, thereby controlling VFB. out The rate of increase in potential slows down.

[0082] When dv / dt_vref is higher than VFB, Ibias1 in the charge pump mostly flows to M1, Ibias1 obtained by M2 is reduced, the current of Ibias2 obtained by M3 in the charge pump is reduced, Ibias2 obtained by MP is increased, the gate of MP is pulled up, thereby V out The potential rising speed is accelerated.

[0083] The embodiment of the present application also provides an electronic device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the control method of the buffer protection circuit provided by the above embodiment when executing the computer program.

[0084] The computer program product provided by the embodiment of the present application includes a computer readable storage medium storing program codes, and the program codes include instructions executable for the method described in the foregoing method embodiments, and the specific implementation can be referred to the method embodiments, which will not be repeated here.

[0085] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system and device can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0086] In addition, in the description of the embodiment of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0087] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or the part of the present application which essentially contributes to the prior art or the part of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0088] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0089] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, and are not limiting. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can make modifications or easily think of changes to the technical solutions recorded in the foregoing embodiments within the technical range disclosed by the present application, or make equivalent replacements to some technical features; and these modifications, changes or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A soft-start protection circuit, characterized by, The application relates to a soft-start protection circuit. The soft-start protection circuit comprises a charge pump, a soft-start module and a power MOS tube; the first end and the second end of the charge pump are connected with the soft-start module respectively; the second end of the charge pump is also connected with the gate of the power MOS tube; the drain of the power MOS tube is connected with a voltage input end, and the source is connected with a voltage output end. The charge pump is used for generating a bias current and inputting the bias current into the soft-start module and the power MOS tube, so that the gate voltage of the power MOS tube is higher than the output voltage of the voltage output end; wherein the bias current comprises a first bias current and a second bias current. The soft-start module is used for adjusting the gate voltage of the power MOS tube according to a preset reference voltage and the bias current, so that the output voltage changes at a change speed of the preset reference voltage. The soft-start protection circuit further comprises a voltage feedback module; the voltage feedback module is used for generating a feedback voltage according to the voltage of the voltage output end, so as to send the feedback voltage to the soft-start module. The soft-start module comprises a first MOS tube and a current mirror circuit; the charge pump is connected with the drain and the gate of the first MOS tube through a first branch of the first end; the charge pump is connected with the first end of the current mirror circuit through a second branch of the first end; the charge pump is connected with the second end of the current mirror circuit through a first branch of the second end; the charge pump is connected with the power MOS tube through a second branch of the second end; the source of the first MOS tube is connected with the voltage feedback module; the second end of the current mirror circuit is connected with the first branch of the second end of the charge pump. When the potential of the feedback voltage is greater than the potential of the preset reference voltage, the charge pump is used for reducing the first MOS current output to the first MOS tube from the first end, increasing the first current mirror current output to the current mirror circuit, enhancing the driving capacity of the current mirror circuit, increasing the second current mirror current output to the current mirror circuit from the second end, and reducing the second MOS current output to the gate of the power MOS tube, so as to reduce the change speed of the output voltage. When the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, the charge pump is used for enhancing the first MOS current output to the first MOS tube from the first end, reducing the first current mirror current output to the current mirror circuit, reducing the driving capacity of the current mirror circuit, reducing the second current mirror current output to the current mirror circuit from the second end, and enhancing the second MOS current output to the gate of the power MOS tube, so as to enhance the output rate of the output voltage. The voltage feedback module comprises a first resistor and a second resistor connected in series; the source of the power MOS tube is connected with the first end of the first resistor; the second end of the first resistor is connected with the first end of the second resistor and the soft-start module; and the second end of the second resistor is grounded.

2. The soft-start protection circuit of claim 1, wherein, The first resistor and the second resistor are used for generating the feedback voltage according to the voltage of the voltage output end, so as to send the feedback voltage to the soft-start module. ​ 3. The soft-start protection circuit of claim 2, wherein, The soft start protection circuit further comprises a voltage variation reference module; a third end of the current mirror circuit is connected with one end of the voltage variation reference module; the other end of the voltage variation reference module is grounded. The voltage variation reference module is configured to output the preset reference voltage to the current mirror circuit. The first MOS current and the first current mirror current are the first bias current; and the second MOS current and the second current mirror current are the second bias current.

4. The soft-start protection circuit of claim 3, wherein, The current mirror circuit comprises a second MOS tube and a third MOS tube; a gate of the second MOS tube is connected with a gate of the third MOS tube; a source of the second MOS tube and a source of the third MOS tube are connected with the voltage variation reference module; a drain of the second MOS tube is connected with the gate of the second MOS tube and a second branch of a first end of the charge pump; a drain of the third MOS tube is connected with a first branch of a second end of the charge pump; a width-length ratio of the second MOS tube and a width-length ratio of the third MOS tube are set according to a preset ratio, so that the third MOS tube enters a deep linear region. The second MOS tube is configured to, when a potential of the feedback voltage is greater than a potential of the preset reference voltage, increase the received first bias current and increase a source voltage of the second MOS tube. When the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, the received first bias current is decreased and the source voltage of the second MOS tube is decreased. The third MOS tube is configured to, when the potential of the feedback voltage is greater than the potential of the preset reference voltage, increase a source voltage of the third MOS tube to increase the obtained second bias current. When the potential of the feedback voltage is less than or equal to the potential of the preset reference voltage, the source voltage of the third MOS tube is decreased to decrease the obtained second bias current.

5. The soft-start protection circuit of claim 4, wherein, The soft start module further comprises a third resistor; one end of the third resistor is connected with the first branch of the first end of the charge pump; the other end of the third resistor is connected with the first MOS tube. The third resistor is configured to, when the reference voltage is 0, generate an input offset current, so that the first bias current flows into the current mirror circuit.

6. The soft-start protection circuit of claim 5, wherein, The soft start protection circuit further comprises a parasitic capacitor; one end of the parasitic capacitor is connected on a connection line between the gate of the power MOS tube and the soft start module; the other end of the parasitic capacitor is grounded.

7. The soft-start protection circuit of claim 6, wherein, The soft start module further comprises a diode; the diode is connected with the current mirror circuit and the gate of the power MOS tube, respectively. The diode is configured to, when the current output by the current mirror circuit is too high, prevent the current from flowing back to the parasitic capacitor.

8. A soft-start protection integrated chip, characterized in that, The body further comprises the soft start protection circuit according to any one of claims 1-7, and the soft start protection circuit is arranged on the body.

9. A control method of a soft-start protection circuit, characterized by, The method is used for controlling the soft start protection circuit according to any one of claims 1-7; the method comprises: generating a bias current by a charge pump; The bias current is input to a soft start module and a power MOS tube, so that a gate voltage of the power MOS tube is higher than an output voltage of the voltage output terminal; The soft start module adjusts the gate voltage of the gate of the power MOS tube according to a preset reference voltage and the bias current, so that the output voltage changes at a change speed of the preset reference voltage.

10. An electronic device comprising a memory, a processor, said memory having stored thereon a computer program operable to run on said processor, characterized in that, The processor implements the method in claim 9 when executing the computer program.

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