Control circuit, linear voltage stabilizing device and linear voltage stabilizing system

Abstract

The invention discloses a control circuit, a linear voltage stabilizing device and a linear voltage stabilizing system, and relates to the field of integrated circuits, the control circuit comprises a low dropout regulator and a pre-bias module, the low dropout regulator comprises a load module, a negative feedback regulation module, a first current source and a first field effect transistor, the source electrode of the first field effect transistor is connected with the negative feedback adjusting module and the load module, the grid electrode of the first field effect transistor is connected with the first current source, the drain electrode of the first field effect transistor is used for being connected with the input voltage of the low dropout linear regulator, the pre-bias module comprises a second current source and an impedance unit, and the second current source is grounded through the impedance unit. The second current source is connected with the grid electrode of the first field-effect tube, the pre-bias voltage is smaller than the threshold voltage of the first field-effect tube, and the pre-bias module is arranged, so that the first field-effect tube is in a critical conduction state, small current is allowed to pass through the first field-effect tube, the current rises slowly, and then surge current is suppressed.

Description

Technical Field

[0001] The present application relates to the field of integrated circuits, and in particular to a control circuit, a linear voltage regulator device and a system. Background Art

[0002] In the prior art, a low voltage dropout linear regulator will generate a large surge current at the moment of connecting to the power supply, that is, a peak current that is much larger than the steady-state current. These rapidly rising and falling currents will repeatedly impact electronic components, thereby shortening the life of the equipment or even damaging the equipment, increasing production costs. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a control circuit, a linear voltage stabilization device and a system, which can suppress the generated surge current, thereby protecting electronic components and reducing production costs.

[0004] The control circuit of the first embodiment of the present application includes:

[0005] A low-voltage dropout linear regulator, the low-voltage dropout linear regulator comprising a load module, a negative feedback regulation module, a first current source and a first field effect transistor, the source of the first field effect transistor is respectively connected to the negative feedback regulation module and the load module, the gate of the first field effect transistor is connected to the first current source, the drain of the first field effect transistor is used to connect the input voltage of the low-voltage dropout linear regulator, and the negative feedback regulation module is used to control the gate of the first field effect transistor to be grounded based on the feedback voltage of the negative feedback regulation module;

[0006] A pre-bias module, the pre-bias module includes a second current source and an impedance unit, the second current source is grounded through the impedance unit, the second current source is connected to the gate of the first field effect transistor, and the impedance unit is used to provide a pre-bias voltage for the gate of the first field effect transistor, and the pre-bias voltage is less than the threshold voltage of the first field effect transistor.

[0007] According to the control circuit of the embodiment of the present application, at least the following beneficial effects are achieved: by setting a pre-bias module, the second current source continuously provides current to the impedance unit, thereby increasing the voltage of the impedance unit, so that the voltage of the impedance unit reaches its on-voltage, and the gate voltage of the first field effect tube gradually rises to the on-voltage of the impedance unit. The on-voltage is the pre-bias voltage provided by the impedance unit to the first field effect tube, and the value of the pre-bias voltage is only slightly smaller than the threshold voltage of the first field effect tube, so that the first field effect tube is in a critical conduction state, causing a small current to flow slowly through the first field effect tube, thereby driving the gate voltage of the first field effect tube to rise slowly, and at the same time charging the load module, driving the output voltage of the load module to start to rise slowly, causing the output voltage change per unit time to be small, and when the gate voltage of the first field effect tube reaches the threshold voltage, the first field effect tube is fully turned on, and during the process of critical conduction and full conduction of the first field effect tube, the current flowing through the first field effect tube is a slowly rising current. state, and when the first field effect tube is fully turned on, the first field effect tube starts to flow a large current, but because the feedback voltage has risen to a certain level at the critical conduction, and after the first field effect tube is fully turned on, in a short time, the output voltage can reach the voltage value started by the negative feedback regulation module, prompting the negative feedback regulation module to adjust the low voltage difference linear regulator, limiting the feedback voltage rise while driving the current to decrease, so that the current flowing through the first field effect tube turns to a downward trend after a short period of adjustment after the first field effect tube is fully turned on, so that no excessive peak current is generated. In the related art, before the first field effect tube is fully turned on, there is no pre-bias module to provide it with a pre-bias voltage, so that after the first field effect tube is fully turned on, the output voltage needs to rise rapidly in a short time, so that the output voltage changes greatly per unit time, until it reaches the voltage value that the negative feedback regulation module can adjust it. In this process, the output voltage drives the rapid rise of the current, and then a large current peak is formed, which is the surge current.

[0008] Thus, a large peak current will not be generated. The provision of a negative feedback regulation module facilitates the control of the gate grounding of the first field effect tube, thereby achieving voltage division of the gate voltage of the first field effect tube, so as to limit the output voltage of the low voltage difference linear regulator, thereby leading to a reduction in current, thereby achieving the effect of suppressing surge current, so as to protect electronic components and reduce production costs.

[0009] According to some embodiments of the present application, the negative feedback regulation module includes a second field effect transistor and an error amplifier, the positive input terminal of the error amplifier is used to connect to the feedback voltage, the reverse input terminal of the error amplifier is used to connect to a preset reference voltage, the output terminal of the error amplifier is connected to the gate of the second field effect transistor, the source of the second field effect transistor is grounded, the drain of the second field effect transistor is connected to the gate of the first field effect transistor, and the error amplifier is used to control the second field effect transistor to turn on when it is detected that the feedback voltage is equal to the preset reference voltage.

[0010] According to some embodiments of the present application, the impedance unit is a third field effect transistor, the source of the third field effect transistor is grounded, and the second current source is respectively connected to the gate and the drain of the third field effect transistor.

[0011] According to some embodiments of the present application, the pre-bias module also includes a first unidirectional diode and a second unidirectional diode, the second current source is connected to the gate of the first field effect transistor through the first unidirectional diode, and the current source is connected to the impedance unit through the second unidirectional diode.

[0012] According to some embodiments of the present application, the low voltage drop linear regulator also includes a charge pump, a first input end of the charge pump is connected to a power supply, and an output end of the charge pump is connected between the first unidirectional diode and the gate of the first field effect transistor through the first current source.

[0013] According to some embodiments of the present application, the load module includes a first capacitor and a first resistor, the first capacitor is connected in parallel with the first resistor, one end of the first capacitor is connected to the source of the first field effect transistor, and the other end is grounded.

[0014] According to some embodiments of the present application, the negative feedback regulation module also includes a second resistor and a third resistor, the source of the first field effect transistor is connected to the positive input terminal of the error amplifier through the second resistor, one end of the third resistor is connected to the positive input terminal of the error amplifier, and the other end is grounded.

[0015] According to some embodiments of the present application, the first unidirectional diode and the second unidirectional diode have the same conduction voltage drop.

[0016] According to the second aspect of the present application, a linear voltage stabilizing device includes:

[0017] The control circuit of the embodiment of the first aspect of the present application.

[0018] According to the linear voltage stabilization device of the embodiment of the present application, at least the following beneficial effects are achieved: by setting a pre-bias module, the second current source continuously provides current to the impedance unit, thereby increasing the voltage of the impedance unit, so that the voltage of the impedance unit reaches its on-voltage, and the gate voltage of the first field effect tube gradually rises to the on-voltage of the impedance unit. The on-voltage is the pre-bias voltage provided by the impedance unit to the first field effect tube, and the value of the pre-bias voltage is only slightly smaller than the threshold voltage of the first field effect tube, so that the first field effect tube is in a critical conduction state, prompting a small current to flow slowly through the first field effect tube, thereby driving the slow rise of the gate voltage of the first field effect tube, and at the same time charging the load module, driving the output voltage of the load module to start to rise slowly, prompting a small output voltage change per unit time, and when the gate voltage of the first field effect tube reaches the threshold voltage, the first field effect tube is fully turned on, and during the process of critical conduction and full conduction of the first field effect tube, the current flowing through the first field effect tube is in a slowly rising state, and when the first field effect tube is fully turned on Afterwards, the first field effect tube begins to flow a large current, but because the feedback voltage has risen to a certain level at the critical conduction, after the first field effect tube is fully turned on, the output voltage can reach the voltage value at which the negative feedback regulation module starts in a short time, prompting the negative feedback regulation module to adjust the low voltage difference linear regulator, limiting the feedback voltage rise while driving the current down, prompting the current flowing through the first field effect tube to turn to a downward trend after a short period of adjustment after the first field effect tube is fully turned on, so that no excessive peak current is generated. In the related art, before the first field effect tube is fully turned on, there is no pre-bias module to provide it with a pre-bias voltage, causing the output voltage of the first field effect tube to rise rapidly in a short time after it is fully turned on, so that the output voltage per unit time changes greatly until it reaches the voltage value that the negative feedback regulation module can adjust it. In this process, the output voltage drives the current to rise rapidly, and then a large current peak value, that is, the surge current, is formed. By introducing the control circuit of the present application, the surge current can be effectively suppressed to achieve protection of electronic components.

[0019] A system according to an embodiment of the third aspect of the present application includes:

[0020] The linear voltage stabilizing device of the second aspect of the present application.

[0021] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 A schematic diagram of a control circuit according to an embodiment of the present application;

[0024] Figure 2 A schematic diagram of a waveform when a low voltage dropout linear regulator in the related art generates a surge current;

[0025] Figure 3 Schematic diagram of the waveform when the control circuit generates surge current according to the embodiment of the present application. DETAILED DESCRIPTION

[0026] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0027] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying 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 specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0028] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0029] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0030] At present, in the existing technology, there are hidden dangers in the use of low-voltage dropout linear regulators. The input and output ends of the low-voltage dropout linear regulator are connected to large filter capacitors. Therefore, at the moment of power-on, a large surge current will be generated, that is, the peak current is much larger than the regulated current. Figure 2When the field effect tube voltage reaches the threshold voltage and then turns on, the current rises rapidly, driving the feedback voltage to rise until the feedback voltage is equal to the preset reference voltage. The current rising trend turns into a downward trend and the current drops rapidly. In this process, the current produces a large current spike, which is the surge current. At the same time, the rapid rise and fall of the current causes the electronic components in the circuit to be repeatedly impacted, thereby shortening the life of the electronic components and even damaging the electronic components. Among them, the surge current refers to the current peak value that appears instantly and exceeds the stable value.

[0031] Based on this, the present application proposes a control circuit, a linear voltage regulator and a system, which aim to suppress surge current through a pre-bias module, thereby protecting electronic components.

[0032] The following references Figure 1 The control circuit of the embodiment of the present application is described.

[0033] It can be understood that: the control circuit of the embodiment of the present application includes a low-voltage difference linear regulator and a pre-bias module, the low-voltage difference linear regulator includes a load module, a negative feedback regulation module, a first current source and a first field effect transistor, the source of the first field effect transistor is respectively connected to the negative feedback regulation module and the load module, the gate of the first field effect transistor is connected to the first current source, the drain of the first field effect transistor is used to connect the input voltage of the low-voltage difference linear regulator, the negative feedback regulation module is used to control the grounding of the gate of the first field effect transistor based on the feedback voltage of the negative feedback regulation module; the pre-bias module includes a second current source and an impedance unit, the second current source is grounded through the impedance unit, the second current source is connected to the gate of the first field effect transistor, and the impedance unit is used to provide a pre-bias voltage for the gate of the first field effect transistor, and the pre-bias voltage is less than the threshold voltage of the first field effect transistor.

[0034] The beneficial effects of the control circuit of the embodiment of the present application can be manifested as follows: by setting a pre-bias module, the second current source continuously provides current to the impedance unit, thereby increasing the voltage of the impedance unit, so that the voltage of the impedance unit reaches its turn-on voltage, and then the gate voltage of the first field effect tube gradually rises to the turn-on voltage of the impedance unit. The turn-on voltage is the pre-bias voltage provided by the impedance unit to the first field effect tube, and the value of the pre-bias voltage is only slightly smaller than the threshold voltage of the first field effect tube, so that the first field effect tube is in a critical conduction state, causing a small current to flow slowly through the first field effect tube, thereby driving the slow increase of the gate voltage of the first field effect tube, and at the same time charging the load module, driving the output voltage of the load module to start to rise slowly, causing the output voltage change per unit time to be small, and when the gate voltage of the first field effect tube reaches the threshold voltage, the first field effect tube is fully turned on, and during the process of critical conduction and full conduction of the first field effect tube, the current flowing through the first field effect tube is in a state of slowly rising. state, and when the first field effect tube is fully turned on, the first field effect tube starts to flow a large current, but because the feedback voltage has risen to a certain level during critical conduction, after the first field effect tube is fully turned on, the output voltage can reach the voltage value started by the negative feedback regulation module in a short time, prompting the negative feedback regulation module to adjust the low voltage difference linear regulator, limiting the feedback voltage rise while driving the current down, prompting the current flowing through the first field effect tube to turn to a downward trend after a short period of regulation after the first field effect tube is fully turned on, so that no excessive peak current is generated. In the related art, before the first field effect tube is fully turned on, there is no pre-bias module to provide it with a pre-bias voltage, so that after the first field effect tube is fully turned on, the output voltage needs to rise rapidly in a short time, so that the output voltage changes greatly per unit time, until it reaches the voltage value that the negative feedback regulation module can adjust it. In this process, the output voltage drives the rapid rise of the current, and then a large current peak is formed, which is the surge current.

[0035] For example, in some embodiments, reference Figure 1 In this embodiment, I CP1is a first current source, M0 is a first field effect tube, I_prebias is a second current source, the first field effect tube includes a second capacitor, Cgs is a second capacitor, the second capacitor is a parasitic capacitor between the gate and source of the first field effect tube, the first current source and the second current source are both constant current sources, so as to provide a constant current for the control circuit of the present application, the part in the dotted line box on the left is a pre-bias module, the drain of the first field effect tube is connected to the input voltage of the low voltage difference linear regulator, and the waveform of the surge current can be obtained by detecting the current IFET, so as to judge whether the control circuit of the present application has a suppressive effect on the surge current, and the second capacitor is continuously charged by the first current source, thereby driving the gate voltage GATE of the first field effect tube to increase, when the gate voltage of the first field effect tube reaches the threshold voltage, the first field effect tube is turned on, and the current IFET flows to the load module through the first field effect tube, thereby driving the output voltage of the load module to increase, and the load module serves as the output pole of the present control circuit, which is convenient for providing a stable Output voltage; one end of the second current source is connected to the power supply, and the other end is grounded through the impedance unit and connected to the gate of the first field effect tube. The impedance unit is continuously charged by the second current source, so that the voltage of the impedance unit gradually increases, thereby driving the gate voltage of the first field effect tube to rise to the pre-bias voltage, and the pre-bias voltage is slightly smaller than the threshold voltage of the first field effect tube. Therefore, the first field effect tube is in a critical conduction state at this time, prompting a small current to flow to the load module through the first field effect tube, thereby driving the output voltage of the load module to rise slowly, thereby avoiding the situation where the surge current peak is too large and changes too fast. The negative feedback regulation module can divide the voltage of the control circuit of the present application as required, and the increase in the output voltage drives the slow increase in the feedback voltage, so that when the gate voltage of the first field effect tube rises to the threshold voltage, that is, it is fully turned on, the negative feedback regulation module can control the gate of the first field effect tube to be grounded based on the feedback voltage, thereby driving the gate voltage of the first field effect tube to decrease, prompting the current IFET to decrease, and avoiding excessive current and damage to the circuit.

[0036] It can be understood that: the negative feedback regulation module includes a second field effect tube and an error amplifier, the positive input terminal of the error amplifier is used to connect to the feedback voltage, the reverse input terminal of the error amplifier is used to connect to the preset reference voltage, the output terminal of the error amplifier is connected to the gate of the second field effect tube, the source of the second field effect tube is grounded, the drain of the second field effect tube is connected to the gate of the first field effect tube, and the error amplifier is used to control the second field effect tube to turn on when it is detected that the feedback voltage is equal to the preset reference voltage.

[0037] For example, in some embodiments, reference Figure 1 In this embodiment, V REF is the preset reference voltage, V FBis the feedback voltage, M2 is the second field effect tube, LDO_EA is the error amplifier, the output end of the error amplifier is connected to the gate of the second field effect tube, the positive input end of the error amplifier is connected to the feedback voltage, and the reverse input end is connected to the preset reference voltage. The error amplifier is used to detect the difference between the feedback voltage and the preset reference voltage. When the feedback voltage is equal to the preset reference voltage, the signal at the output end of the error amplifier controls the second field effect tube to conduct, causing the gate of the first field effect tube to be grounded, thereby reducing the gate voltage of the first field effect tube, driving the current IFET to decrease, and avoiding excessive current.

[0038] It should be noted that the preset reference voltage is a linearly rising voltage, and the rising speed of the preset reference voltage determines the soft-start rate of the low-dropout linear regulator. The soft-start of the low-dropout linear regulator means that when the low-dropout linear regulator is started, the output voltage is gradually increased by controlling the internal circuit or external resistance.

[0039] It can be understood that: the impedance unit is a third field effect transistor, the source of the third field effect transistor is grounded, and the second current source is respectively connected to the gate and the drain of the third field effect transistor.

[0040] For example, in some embodiments, reference Figure 1 In this embodiment, M1 is the third field effect transistor, and the gate-source voltage of the third field effect transistor is slightly smaller than the threshold voltage of the first field effect transistor, so as to provide a pre-bias voltage for the first field effect transistor, so as to cause the first field effect transistor to be in a critical conduction state, drive the current IFET to rise slowly, and prevent the current from rising too fast and causing impact on electronic components.

[0041] It can be understood that: the pre-bias module further includes a first unidirectional diode and a second unidirectional diode, the second current source is connected to the gate of the first field effect transistor through the first unidirectional diode, and the current source is connected to the impedance unit through the second unidirectional diode.

[0042] For example, in some embodiments, reference Figure 1 In this embodiment, D1 is a first unidirectional diode, D2 is a second unidirectional diode, the positive terminal of the first unidirectional diode is connected to the second current source, the negative terminal of the first unidirectional diode is connected to the gate of the first field effect tube, to prevent the current from the second current source flowing to the first field effect tube from flowing back, the positive terminal of the second unidirectional diode is connected to the second current source, the negative terminal of the first unidirectional diode is connected to the gate and drain of the third field effect tube, to prevent the current from the second current source flowing to the third field effect tube from flowing back, and at the same time, the pre-bias voltage formula provided by the third field effect tube to the first field effect tube is as follows:

[0043] V PB =V GS1 +V F2 -VF1 ;

[0044] Among them, V PB is the pre-bias voltage, V GS1 is the gate-source voltage of the third field effect tube, V F1 is the conduction voltage drop of the first unidirectional diode, V F2 is the conduction voltage drop of the second unidirectional diode, the pre-bias voltage is less than the threshold voltage of the first field effect tube, the pre-bias module provides the pre-bias voltage for the first field effect tube, prompting the gate voltage of the first field effect tube to rise to the pre-bias voltage, but because the pre-bias voltage is slightly less than the threshold voltage of the first field effect tube, the first field effect tube is prompted to be in a critical conduction state, and then a slowly rising small current flows through the first field effect tube to the load module, driving the output voltage to rise slowly.

[0045] It can be understood that the low voltage drop linear regulator also includes a charge pump, a first input end of the charge pump is connected to the power supply, and an output end of the charge pump is connected between the first unidirectional diode and the gate of the first field effect transistor through the first current source.

[0046] For example, in some embodiments, reference Figure 1 In this embodiment, the charge pump is a charge pump, a first input terminal of the charge pump is connected to a power supply, a second input terminal is connected to an input voltage of a low voltage dropout linear regulator, and an output terminal of the charge pump is connected between a negative terminal of a first unidirectional diode and a gate of a first field effect transistor through a first current source, so as to enhance the function and performance of the low voltage dropout linear regulator.

[0047] It can be understood that: the load module includes a first capacitor and a first resistor, the first capacitor is connected in parallel with the first resistor, one end of the first capacitor is connected to the source of the first field effect transistor, and the other end is grounded.

[0048] For example, in some embodiments, reference Figure 1 In this embodiment, Cout is the first capacitor, R LOAD The first resistor, the first capacitor and the first resistor form an output stage of a low voltage difference linear regulator, which is convenient for detecting and stabilizing the output voltage.

[0049] It can be understood that: the negative feedback regulation module also includes a second resistor and a third resistor, the source of the first field effect tube is connected to the positive input terminal of the error amplifier through the second resistor, one end of the third resistor is connected to the positive input terminal of the error amplifier, and the other end is grounded.

[0050] For example, in some embodiments, reference Figure 1In this embodiment, R1 is the second resistor, R2 is the third resistor, and the setting of the second resistor and the third resistor facilitates voltage division of the control circuit of the present application as needed. The feedback voltage connected to the positive input terminal of the error amplifier is the voltage divided by the third resistor.

[0051] It can be understood that: the conduction voltage drop of the first unidirectional diode and the second unidirectional diode is the same.

[0052] For example, in some embodiments, reference Figure 1 In this embodiment, the voltage drop of the first unidirectional diode and the second unidirectional diode is the same, that is, V F1 and V F2 Equal, so through the above pre-bias voltage formula, we can know that when V F1 and V F2 When the third FET provides a pre-bias voltage V for the first FET, PB Equal to the gate-source voltage V of the third field effect tube GS1 At the same time, the gate-source voltage of the third field effect tube is slightly smaller than the threshold voltage of the first field effect tube, so that when the gate voltage of the first field effect tube is increased to the pre-bias voltage, the first field effect tube can be in a critical conduction state, and the setting of the first unidirectional diode and the second unidirectional diode having the same voltage drop makes the value of the pre-bias voltage depend on the gate-source voltage of the third field effect tube, which is more conducive to the control of the pre-bias voltage.

[0053] Reference Figure 1 , the formula obtained by performing small signal analysis on the control circuit of this application is as follows:

[0054]

[0055] Among them, Av 0 is the gain of LDO_EA, g m0 is the current gain of M0, △V OUT is the change of output voltage per unit time. 0 , g m0 is a constant value, which can be expressed by Gm. It can be seen from the formula that if the output voltage changes suddenly, it will cause a surge current in the current IFET. The pre-bias module of this application is to reduce △V at startup. OUT To suppress surge current.

[0056] Reference Figure 1 and Figure 3 , the control circuit of this application is analyzed from a large signal perspective, and the formula for the surge current when the control circuit of this application is started is as follows:

[0057]

[0058] Among them, IP1 is the peak value of surge current, V t2 t 2 Output voltage at time t 1 is the moment when the feedback voltage starts to rise, t 2 is the moment when the feedback voltage is equal to the preset reference voltage. At the same time, due to the second field effect tube at t 2 It starts to conduct at the moment, causing the gate of the first field effect tube to be grounded, which in turn drives the current IFET down, causing IFET to change from an upward trend to a downward trend. Therefore, t 2 This is also the moment when the surge current reaches its peak value, t 0 is the moment when the first current source starts to charge the second capacitor, t 3 It is the moment when the input voltage and output voltage of the low-dropout linear regulator are equal, and VIN is the input voltage of the low-dropout linear regulator.

[0059] And V t2 It can also be expressed as:

[0060]

[0061] Where K is V REF The rising slope, V th is the threshold voltage of M0. t2 Substituting the expression into the surge current formula, we can get:

[0062]

[0063] It can be obtained that the surge current peak value I P1 The size and time difference t 2 -t 1 Inversely proportional, so increase the time difference t 2 -t 1 The surge current at the moment of starting the control circuit of the present application can be suppressed. The control circuit of the present application, by setting a pre-bias module, provides a pre-bias voltage to the first field effect tube before it is turned on, so that the first field effect tube is in a critical conduction state. At this time, a small current begins to pass through the first field effect tube, thereby driving the feedback voltage to rise slowly until the feedback voltage is equal to the preset reference voltage. By limiting the flow rate of the current, the time difference t is increased. 2 -t 1 , so as to achieve the effect of suppressing surge current, refer to Figure 3 It can be seen that when the gate voltage of the first field effect tube rises to the pre-bias voltage and is about to be turned on, the surge current begins to rise slowly due to the small current passing through the first field effect tube. When the feedback voltage is equal to the preset reference voltage, the surge current reaches the highest peak value. Figure 2 and Figure 3At this time, the peak value of the surge current is significantly reduced compared with the prior art.

[0064] The linear voltage stabilizing device according to the second aspect of the application includes the control circuit of the first aspect of the application.

[0065] According to the linear voltage stabilization device of the embodiment of the present application, a pre-bias module is provided, and the second current source continuously provides current to the impedance unit, thereby increasing the voltage of the impedance unit, so that the voltage of the impedance unit reaches its on-voltage, and the gate voltage of the first field effect tube gradually rises to the on-voltage of the impedance unit. The on-voltage is the pre-bias voltage provided by the impedance unit to the first field effect tube, and the value of the pre-bias voltage is only slightly smaller than the threshold voltage of the first field effect tube, so that the first field effect tube is in a critical conduction state, causing a small current to flow slowly through the first field effect tube, thereby driving the slow increase of the gate voltage of the first field effect tube, and also charging the load module, driving the output voltage of the load module to start to rise slowly, causing the output voltage change per unit time to be small, and when the gate voltage of the first field effect tube reaches the threshold voltage, the first field effect tube is fully turned on, and during the process of critical conduction and full conduction of the first field effect tube, the current flowing through the first field effect tube is in a slowly rising state, and after the first field effect tube is fully turned on, the first field The field effect tube begins to flow a large current, but because the feedback voltage has risen to a certain level at the critical conduction, after the first field effect tube is fully turned on, the output voltage can reach the voltage value at which the negative feedback regulation module starts in a short time, prompting the negative feedback regulation module to adjust the low voltage difference linear regulator, limiting the feedback voltage rise while driving the current down, prompting the current flowing through the first field effect tube to turn to a downward trend after a short period of adjustment after the first field effect tube is fully turned on, so that no excessive peak current is generated. In the related art, before the first field effect tube is fully turned on, there is no pre-bias module to provide it with a pre-bias voltage, resulting in the output voltage of the first field effect tube to rise rapidly in a short time after it is fully turned on, so that the output voltage per unit time changes greatly until it reaches the voltage value that the negative feedback regulation module can adjust it. In this process, the output voltage drives the current to rise rapidly, and then a large current peak is formed, which is the surge current. By introducing the control circuit of the present application, the surge current can be effectively suppressed to achieve protection of electronic components.

[0066] Since the linear voltage stabilizing device includes the control circuit of the first aspect embodiment, the corresponding contents of the control circuit in the first aspect embodiment can be applied to the linear voltage stabilizing device of the second aspect, and have the same implementation principle and technical effect. In order to avoid redundant description, it will not be described in detail here.

[0067] The system according to the third aspect embodiment of the application includes the linear voltage stabilizing device of the second aspect embodiment of the application.

[0068] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0069] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0070] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0071] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0072] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0073] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0074] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0075] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0076] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0077] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including multiple instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), disk or optical disk and other media that can store programs.

[0078] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A control circuit, characterized in that: The control circuit comprises: A low-voltage dropout linear regulator, the low-voltage dropout linear regulator comprising a load module, a negative feedback regulation module, a first current source and a first field effect transistor, the source of the first field effect transistor is respectively connected to the negative feedback regulation module and the load module, the gate of the first field effect transistor is connected to the first current source, the drain of the first field effect transistor is used to connect the input voltage of the low-voltage dropout linear regulator, and the negative feedback regulation module is used to control the gate of the first field effect transistor to be grounded based on the feedback voltage of the negative feedback regulation module; A pre-bias module, the pre-bias module includes a second current source and an impedance unit, the second current source is grounded through the impedance unit, the second current source is connected to the gate of the first field effect transistor, and the impedance unit is used to provide a pre-bias voltage for the gate of the first field effect transistor, and the pre-bias voltage is less than the threshold voltage of the first field effect transistor.

2. The control circuit according to claim 1, characterized in that: The negative feedback regulation module includes a second field effect transistor and an error amplifier, the positive input terminal of the error amplifier is used to access the feedback voltage, the reverse input terminal of the error amplifier is used to access the preset reference voltage, the output terminal of the error amplifier is connected to the gate of the second field effect transistor, the source of the second field effect transistor is grounded, the drain of the second field effect transistor is connected to the gate of the first field effect transistor, and the error amplifier is used to control the second field effect transistor to turn on when it is detected that the feedback voltage is equal to the preset reference voltage.

3. The control circuit according to claim 1, characterized in that: The impedance unit is a third field effect transistor, the source of the third field effect transistor is grounded, and the second current source is respectively connected to the gate and the drain of the third field effect transistor.

4. The control circuit according to claim 1, characterized in that: The pre-bias module further includes a first unidirectional diode and a second unidirectional diode, the second current source is connected to the gate of the first field effect transistor through the first unidirectional diode, and the current source is connected to the impedance unit through the second unidirectional diode.

5. The control circuit according to claim 4, characterized in that: The low voltage difference linear regulator also includes a charge pump, a first input end of the charge pump is connected to a power supply, and an output end of the charge pump is connected between the first unidirectional diode and the gate of the first field effect transistor through the first current source.

6. The control circuit according to claim 1, characterized in that: The load module includes a first capacitor and a first resistor. The first capacitor is connected in parallel with the first resistor. One end of the first capacitor is connected to the source of the first field effect transistor, and the other end is grounded.

7. The control circuit according to claim 2, characterized in that: The negative feedback regulation module also includes a second resistor and a third resistor. The source of the first field effect transistor is connected to the positive input terminal of the error amplifier through the second resistor. One end of the third resistor is connected to the positive input terminal of the error amplifier, and the other end is grounded.

8. The control circuit according to claim 4, characterized in that: The first unidirectional diode and the second unidirectional diode have the same conduction voltage drop.

9. A linear voltage stabilizing device, characterized in that: include: A control circuit as claimed in any one of claims 1 to 8.

10. A system, characterized in that: include: The linear voltage regulator device as claimed in claim 9.

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