A fast current limiting circuit applied to a negative voltage linear regulator
Patent Information
- Application Number
- CN202522824922.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-30
AI Technical Summary
Traditional current limiting protection circuits in power MOSFETs suffer from low accuracy, slow response speed, low efficiency, and large chip area requirements. There is an urgent need for a high-efficiency, fast current limiting solution that does not require external components.
A fast current limiting circuit for a negative voltage linear regulator is designed, including an output module, a current sampling module, a current comparison module, and a current feedback module. The output current is directly compared through a current mirror structure, and the output current is modulated by the current feedback module when the conversion current exceeds the bias current source, thereby achieving high precision and fast current limiting.
It improves the efficiency and accuracy of the current limiting circuit, reduces power consumption, achieves faster response speed, and has a compact circuit structure that is easy to integrate, making it suitable for negative voltage linear regulators.
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Figure CN224934349U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electronic circuit technology, and in particular to a fast current limiting circuit applied to a negative voltage linear regulator. Background Technology
[0002] In power management, power drive and other circuit applications, power MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors) are core components that carry high voltage and high current in high-power scenarios. To ensure their normal operation and prevent the power MOSFET from burning out due to load short circuits, overloads and other reasons, which could lead to system failure, effective current limiting protection measures are required for power MOSFETs.
[0003] Traditional current-limiting protection circuits often use a sampling resistor connected in series with the source of the power MOSFET, determining the current magnitude by detecting the voltage across the sampling resistor. This method incurs continuous power loss across the sampling resistor, reducing system efficiency; furthermore, it requires a large-area resistor in the integrated circuit design, occupying a significant chip area. Alternatively, a small-sized sampling transistor proportional to the power MOSFET's current can be used to mirror the MOSFET's current, and the sampled current is then converted to voltage through a resistor and compared with a reference voltage. While this method avoids power loss, its accuracy is significantly affected by the resistance value, temperature, and comparator offset voltage, and its response speed is relatively slow. Therefore, there is an urgent need to address the shortcomings of existing current-limiting protection methods, such as low accuracy, slow response speed, low efficiency, or large chip area. A highly efficient current-limiting solution that achieves high accuracy, fast response, and requires no external components is urgently needed. Summary of the Invention
[0004] To address the problems mentioned in the background section, this application provides the following technical solutions: A fast current limiting circuit for a negative voltage linear regulator is provided, comprising: an output module, a current sampling module, a current comparison module, and a current feedback module.
[0005] The current feedback module includes a bias current source.
[0006] The output module and the current sampling module are both connected to the current comparison module. The current comparison module is connected to the current feedback module. The current feedback module is connected to the output module and the current sampling module.
[0007] The current sampling module detects the output current of the output module to determine the detection current and transmits the detection current to the current comparison module. The current comparison module determines the first voltage at its connection point with the current feedback module based on the detection current. When the conversion current generated by the first voltage is greater than the current value provided by the bias current source, the current feedback module suppresses the increase in the amplitude of the output current.
[0008] Furthermore, the output module has: a first output module port, a second output module port, a third output module port, and a fourth output module port.
[0009] The current sampling module has: a first current sampling port, a second current sampling port, and a third current sampling port.
[0010] The current comparison module has: a first current comparison port, a second current comparison port, a third current comparison port, and a fourth current comparison port.
[0011] The current feedback module has: a first current feedback port, a second current feedback port, a third current feedback port, a fourth current feedback port, and a fifth current feedback port.
[0012] The first port of the output module and the second port of the current sampling are used to connect to the input voltage. The second port of the output module is connected to the first port of the current comparison and is used to provide the output current to the first port of the current comparison. The third port of the output module is connected to the first port of the current sampling and the third port of the current feedback. The third port of the current sampling is connected to the second port of the current comparison and is used to transmit the detection current determined according to the output current. The third port of the current comparison is connected to the first port of the current feedback. The second port of the current feedback is used to connect to the adjustment current. The fourth port of the output module is connected to the fourth port of the current comparison and the fourth port of the current feedback and then grounded. The fifth port of the current feedback is used to connect to the input voltage.
[0013] Furthermore, the output module includes a first transistor and a first capacitor.
[0014] The source of the first transistor serves as the first port of the output module, the gate of the first transistor serves as the third port of the output module, the drain of the first transistor is connected to one end of the first capacitor, and the other end of the first capacitor serves as the fourth port of the output module.
[0015] Furthermore, the current sampling module includes a sampling transistor.
[0016] The gate of the sampling transistor serves as the first port for current sampling, the source of the sampling transistor serves as the second port for current sampling (used to connect the input voltage), and the drain of the sampling transistor serves as the third port for current sampling.
[0017] Furthermore, the current comparison module includes a second transistor, a third transistor, a fourth transistor, and a fifth transistor.
[0018] The gate of the second transistor is connected to the gate of the third transistor, the drain of the third transistor, and the drain of the fifth transistor to form the third port for current comparison. The source of the second transistor is connected to the source of the third transistor to form the fourth port for current comparison. The drain of the second transistor is connected to the drain of the fourth transistor, the gate of the fourth transistor, and the gate of the fifth transistor. The source of the fourth transistor serves as the first port for current comparison, and the source of the fifth transistor serves as the second port for current comparison.
[0019] Furthermore, the current feedback module includes: a sixth transistor, a seventh transistor, an eighth transistor, a first resistor, a second capacitor, and a bias current source.
[0020] One end of the bias current source is connected to one end of the first resistor to serve as the fifth port for current feedback. The other end of the bias current source is connected to the drain of the sixth transistor, one end of the second capacitor, and the gate of the seventh transistor. The gate of the sixth transistor serves as the first port for current feedback. The source of the sixth transistor is connected to the other end of the second capacitor to serve as the fourth port for current feedback. The source of the seventh transistor serves as the second port for current feedback. The drain of the seventh transistor is connected to the drain of the eighth transistor and the gate of the eighth transistor to serve as the third port for current feedback. The source of the eighth transistor is connected to the other end of the first resistor.
[0021] Furthermore, the fast current limiting circuit applied to the negative voltage linear regulator also includes a voltage feedback module.
[0022] The voltage feedback module has: a voltage feedback first port, a voltage feedback second port, and a voltage feedback third port.
[0023] The first voltage feedback port is used to connect the output voltage. The second voltage feedback port is connected to the second current feedback port of the current feedback module and is used to provide adjustment current to the second current feedback port. The third voltage feedback port is grounded.
[0024] Furthermore, the voltage feedback module includes a voltage divider network, an operational amplifier, and a ninth transistor.
[0025] The voltage divider network has: a first port, a second port, and a third port.
[0026] The first port of the voltage divider network serves as the first voltage feedback port. The second port of the voltage divider network is connected to the source of the ninth transistor and serves as the third voltage feedback port. The third port of the voltage divider network is connected to the non-inverting input of the operational amplifier. The inverting input of the operational amplifier is connected to the reference voltage. The output of the operational amplifier is connected to the gate of the ninth transistor. The drain of the ninth transistor serves as the second voltage feedback port.
[0027] Furthermore, the voltage divider network includes a second resistor and a third resistor.
[0028] One end of the second resistor serves as the first port of the voltage divider network. The other end of the second resistor is connected to one end of the third resistor to serve as the third port of the voltage divider network. The other end of the third resistor serves as the second port of the voltage divider network.
[0029] Furthermore, the input voltage applied to the fast current limiting circuit of the negative voltage linear regulator is lower than the ground potential.
[0030] By implementing the fast current limiting circuit for a negative voltage linear regulator described in this application, the circuit efficiency is improved by directly comparing currents, eliminating error sources in traditional sampling methods, and achieving higher precision and faster current limiting functions. At the same time, the circuit structure is compact and easy to integrate. The current comparison module directly compares the detected current obtained from the output current through a current mirror structure, improving the response speed of the current comparison and reducing circuit power consumption. When the conversion current converted from the load current exceeds the current magnitude of the bias current source, the current feedback module intervenes to modulate the output current, quickly and accurately limiting the magnitude of the output current. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic diagram of a fast current limiting circuit module for a negative voltage linear regulator provided in an embodiment of this application; Figure 2 This is a schematic diagram of the output module circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of the current sampling module circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of the current comparison module circuit provided in an embodiment of this application; Figure 5This is a schematic diagram of the current feedback module circuit provided in an embodiment of this application; Figure 6 This is a schematic diagram of the voltage feedback module circuit provided in an embodiment of this application; Figure 7 This is a schematic diagram of a fast current limiting circuit applied to a negative voltage linear regulator, provided in an embodiment of this application. Figure 8 This is a simulation diagram of a fast current limiting circuit applied to a negative voltage linear regulator, provided in an embodiment of this application. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0034] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The numbers in the accompanying drawings are only used to distinguish individual functional parts or modules and do not indicate logical relationships between parts or modules. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. “Above,” “below,” “left,” “right,” etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0035] The various embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are assigned to components having substantially the same or similar structure and function, and repeated descriptions of them will be omitted.
[0036] Traditional sampling methods for current limiting protection circuits result in drawbacks such as high power consumption, low current limiting accuracy, slow response speed, and large chip area footprint. To address these issues, this application provides the following technical solution.
[0037] In some embodiments, such as Figure 1 As shown, a fast current limiting circuit for a negative voltage linear regulator includes: an output module 100, a current sampling module 200, a current comparison module 300, and a current feedback module 400.
[0038] The current feedback module 400 includes a bias current source I bias .
[0039] The output module 100 and the current sampling module 200 are both connected to the current comparison module 300. The current comparison module 300 is connected to the current feedback module 400. The current feedback module 400 is connected to the output module 100 and the current sampling module 200.
[0040] The current sampling module 200 detects the output current of the output module 100 to determine the detection current, and transmits the detection current to the current comparison module 300. The current comparison module 300 determines the first voltage at its connection point with the current feedback module 400 based on the detection current. The current feedback module 400 then determines the voltage at which the conversion current generated by the first voltage is greater than the bias current source I. bias When the provided current value is given, the increase in the amplitude of the output current is suppressed.
[0041] Preferably, the fast current limiting circuit described in this application for a negative voltage linear regulator is suitable for a negative voltage low-dropout linear regulator (LDO). The input and output voltages of this low-dropout linear regulator are both negative, and the highest potential in the circuit is ground.
[0042] The current sampling module 200 obtains a detection current corresponding to the output current through a current mirror structure, and this detection current is directly transmitted to the current comparison module 300. The magnitude of the detection current will affect the magnitude of the first voltage V1 at the connection between the third port 300c of the current comparison module 300 and the first port 400a of the current feedback module 400. The current feedback module further determines the voltage based on the magnitude of the first voltage V1 and its built-in bias current source I. bias The current value is used to determine the drive voltage V output by the current feedback module to the output module 100. DR Furthermore, the conversion current generated by the first voltage is greater than the bias current source I. bias When the provided current value is given, the increase in the amplitude of the output current is suppressed.
[0043] Specifically, the output module 100 has: a first output module port 100a, a second output module port 100b, a third output module port 100c, and a fourth output module port 100d.
[0044] The current sampling module 200 has: a first current sampling port 200a, a second current sampling port 200b, and a third current sampling port 200c.
[0045] The current comparison module 300 has: a first current comparison port 300a, a second current comparison port 300b, a third current comparison port 300c, and a fourth current comparison port 300d.
[0046] The current feedback module 400 has: a first current feedback port 400a, a second current feedback port 400b, a third current feedback port 400c, a fourth current feedback port 400d, and a fifth current feedback port 400e.
[0047] The first port 100a of the output module and the second port 200b of the current sampling are used to connect the input voltage V. IN The second port 100b of the output module is connected to the first port 300a of the current comparison module, and is used to provide output current to the first port 300a of the current comparison module. The third port 100c of the output module is connected to the first port 200a of the current sampling module and the third port 400c of the current feedback module. The third port 200c of the current sampling module is connected to the second port 300b of the current comparison module, and is used to transmit the detection current determined according to the output current. The third port 300c of the current comparison module is connected to the first port 400a of the current feedback module, and the second port 400b of the current feedback module is used to connect the adjustment current. The fourth port 100d of the output module is connected to the fourth port 300d of the current comparison module and the fourth port 400d of the current feedback module, and is then grounded. The fifth port 400e of the current feedback module is used to connect the input voltage V. IN .
[0048] The current sampling module 200 uses a current mirror structure to sample the output current to the branch connected to the second current comparison port 300b. Since the current mirror samples the current based on the transistor width-to-length ratio, it avoids the influence of the temperature effect of resistance and improves sampling accuracy. The width-to-length ratios of the second transistor T2 and the third transistor T3, as well as the width-to-length ratios of the fourth transistor T4 and the fifth transistor T5, are typically set to the same ratio. This ratio setting allows for flexible adaptation to the bias current source I. bias The current value and transistor process parameters are correlated, allowing for more flexible parameter settings. Indicatively, this ratio can be set to 1:5.
[0049] like Figure 2 As shown, the output module 100 includes a first transistor T1 and a first capacitor C1.
[0050] The source of the first transistor T1 serves as the first port 100a of the output module, the gate of the first transistor T1 serves as the third port 100c of the output module, the drain of the first transistor T1 is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 serves as the fourth port 100d of the output module.
[0051] The first transistor T1 is an N-channel power MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). Since the source of the first transistor T1 is connected to the input voltage V at the first port 100a of the output module... IN Its drain serves as the voltage output terminal, providing output voltage and output current to the load. Since the first transistor T1 operates in a scenario of high current, high voltage, and high power energy conversion, a power transistor is used as the first transistor T1.
[0052] like Figure 3 As shown, the current sampling module 200 includes a sampling transistor T S .
[0053] Sampling transistor T S The gate of the transistor is used as the first port 200a for current sampling, and the sampling transistor T is used as the sampling transistor. S The source terminal serves as the second current sampling port 200b, used to connect the input voltage V. IN Sampling transistor T S The drain is used as the third port 200c for current sampling.
[0054] Sampling transistor T S It is an N-channel metal-oxide-semiconductor field-effect transistor.
[0055] like Figure 4 As shown, the current comparison module 300 includes: a second transistor T2, a third transistor T3, a fourth transistor T4, and a fifth transistor T5.
[0056] The gate of the second transistor T2 is connected to the gate of the third transistor T3, the drain of the third transistor T3, and the drain of the fifth transistor T5, forming the third port 300c for current comparison. The source of the second transistor T2 is connected to the source of the third transistor T3, forming the fourth port 300d for current comparison. The drain of the second transistor T2 is connected to the drain of the fourth transistor T4, the gate of the fourth transistor T4, and the gate of the fifth transistor T5. The source of the fourth transistor T4 forms the first port 300a for current comparison, and the source of the fifth transistor T5 forms the second port 300b for current comparison.
[0057] The second transistor T2 and the third transistor T3 are both P-channel metal-oxide-semiconductor field-effect transistors; the fourth transistor T4 and the fifth transistor T5 are both N-channel metal-oxide-semiconductor field-effect transistors.
[0058] like Figure 5 As shown, the current feedback module 400 includes: a sixth transistor T6, a seventh transistor T7, an eighth transistor T8, a first resistor R1, a second capacitor C2, and a bias current source I. bias .
[0059] Bias current source I bias One end is connected to one end of the first resistor R1 and serves as the fifth port 400e for current feedback, biasing the current source I. bias The other end is connected to the drain of the sixth transistor T6, one end of the second capacitor C2, and the gate of the seventh transistor T7. The gate of the sixth transistor T6 serves as the first current feedback port 400a. The source of the sixth transistor T6 is connected to the other end of the second capacitor C2 and serves as the fourth current feedback port 400d. The source of the seventh transistor T7 serves as the second current feedback port 400b, through which the adjustment current flows. The drain of the seventh transistor T7 is connected to the drain of the eighth transistor T8 and the gate of the eighth transistor T8 and serves as the third current feedback port 400c. The source of the eighth transistor T8 is connected to the other end of the first resistor R1.
[0060] The sixth transistor T6 and the seventh transistor T7 are both P-channel metal-oxide-semiconductor field-effect transistors; the eighth transistor T8 is an N-channel metal-oxide-semiconductor field-effect transistor.
[0061] The conversion current refers to the current flowing through the sixth transistor T6.
[0062] The adjustment current refers to the current flowing through the source of the seventh transistor T7.
[0063] When the sampling transistor T S After the mirrored output current, the detection current flows through the third transistor T3, the fifth transistor T5, and the sampling transistor T6. S The branch circuit is composed of transistors. Since the third transistor T3 uses a diode connection, according to the saturated Sachs equation, the magnitude of the current flowing through it changes in the same direction as the magnitude of its drain voltage. When the detected current increases, the magnitude of the drain voltage of the third transistor T3 increases. Furthermore, since the third transistor T3 is a P-channel metal-oxide-semiconductor field-effect transistor, the drain voltage of the third transistor T3 becomes more "negative" relative to ground potential. Therefore, the first voltage V1 becomes smaller relative to ground potential. This causes the conversion current flowing through the sixth transistor T6 to increase. When the conversion current exceeds the bias current source I... biasAfter determining the current magnitude, the current feedback module 400 starts working and modulates the output current. The specific modulation method is as follows: When the conversion current increases due to the increase in output current, the increased conversion current causes the gate voltage amplitude of the seventh transistor T7 to increase, thereby increasing the adjustment current flowing through the seventh transistor T7. This increases the voltage drop between the drain of the eighth transistor T8 and one end of the first resistor R1. Since one end of the first resistor R1 is connected to the input voltage V... IN Therefore, the drain voltage amplitude of the seventh transistor T7 decreases, which in turn lowers the gate voltage of the first transistor T1. This decrease in the gate voltage of the first transistor T1 limits further increases in the output current. This negative feedback mechanism creates current-limiting protection for the output current. If the current required by the load then tends to increase further, current will be drawn from the first capacitor C1, leading to a drop in the output voltage.
[0064] like Figure 1 As shown, the fast current limiting circuit applied to the negative voltage linear regulator also includes a voltage feedback module 500.
[0065] The voltage feedback module 500 has: a voltage feedback first port 500a, a voltage feedback second port 500b, and a voltage feedback third port 500c.
[0066] The voltage feedback first port 500a is used to connect the output voltage V. OUT The voltage feedback second port 500b is connected to the current feedback second port 400b of the current feedback module 400, and is used to provide adjustment current to the current feedback second port 400b. The voltage feedback third port 500c is grounded.
[0067] like Figure 6 As shown, the voltage feedback module 500 includes: a voltage divider network 510, an operational amplifier 520, and a ninth transistor T9.
[0068] The ninth transistor, T9, is a P-channel metal-oxide-semiconductor field-effect transistor.
[0069] The voltage divider network 510 has: a first voltage divider network port 510a, a second voltage divider network port 520b, and a third voltage divider network port 510c.
[0070] The first port 510a of the voltage divider network serves as the first voltage feedback port 500a. The second port 520b of the voltage divider network, after being connected to the source of the ninth transistor T9, serves as the third voltage feedback port 500c. The third port 510c of the voltage divider network is connected to the non-inverting input of the operational amplifier 520, and the inverting input of the operational amplifier 520 is connected to the reference voltage V. REFThe output of operational amplifier 520 is connected to the gate of the ninth transistor T9, and the drain of the ninth transistor T9 serves as the second voltage feedback port 500b. When the second voltage feedback port 500b is connected to the second current feedback port 400b, it provides adjustment current to the second current feedback port 400b.
[0071] The voltage divider network 510 includes a second resistor R2 and a third resistor R3.
[0072] One end of the second resistor R2 serves as the first port 510a of the voltage divider network. The other end of the second resistor R2 is connected to one end of the third resistor R3 and serves as the third port 510c of the voltage divider network. The other end of the third resistor R3 serves as the second port 520b of the voltage divider network.
[0073] The ninth transistor T9 acts as a buffer, increasing the driving capability of the first transistor T1 and allowing for a wider range of adjustment in the output current.
[0074] The input voltage applied to the fast current limiting circuit used in the negative voltage linear regulator is lower than the ground potential.
[0075] Figure 7 The circuit diagram of the fast current limiting circuit applied to a negative voltage linear regulator is shown below. (See below for comparison.) Figure 7 The working principle of the fast current limiting circuit applied to the negative voltage linear regulator is described in detail.
[0076] For the conversion current not exceeding the bias current source I bias When the current magnitude increases, the voltage feedback module 500 intervenes to modulate the output voltage. The specific modulation method is as follows: In response to the increase in output current, the first capacitor C1 first compensates for the additional output current. At this time, the output voltage shows a decreasing trend, causing the voltage amplitude at the output terminal of the operational amplifier 520 to decrease, reducing the adjustment current flowing through the ninth transistor T9, and consequently reducing the adjustment current flowing through the seventh transistor T7. This reduces the voltage drop between the drain of the eighth transistor T8 and one end of the first resistor R1. Furthermore, since one end of the first resistor R1 is connected to the input voltage V... IN Therefore, the drain voltage amplitude of the seventh transistor T7 is increased, which in turn increases the gate voltage of the first transistor T1. By increasing the driving capability of the first transistor T1, the increase in output current is compensated.
[0077] When the conversion current exceeds the bias current source I biasAfter determining the current magnitude, the current feedback module 400 starts working and modulates the output current. The specific modulation method is as follows: When the conversion current increases due to the increase in output current, the increased conversion current causes the gate voltage amplitude of the seventh transistor T7 to increase, thereby increasing the adjustment current flowing through the seventh transistor T7. This increases the voltage drop between the drain of the eighth transistor T8 and one end of the first resistor R1. Since one end of the first resistor R1 is connected to the input voltage V... IN Therefore, the drain voltage amplitude of the seventh transistor T7 decreases, which in turn lowers the gate voltage of the first transistor T1. This decrease in the gate voltage of the first transistor T1 limits further increases in the output current. This negative feedback mechanism creates current-limiting protection for the output current. If the current required by the load then tends to increase further, current will be drawn from the first capacitor C1, leading to a drop in the output voltage.
[0078] The switching point for the modulation of the first transistor T1 by the current feedback module 400 and the voltage feedback module 500 depends on whether the conversion current is greater than the bias current source I. bias The magnitude of the current. When the switching current is less than the bias current source I... bias When the current is large, the voltage feedback module 500 intervenes to adjust the output voltage; when the conversion current is greater than the bias current source I... bias When the current is large, the current feedback module 400 intervenes to limit the output current.
[0079] Figure 8 Simulation results of a fast current-limiting circuit applied to a negative voltage linear regulator are shown. From Figure 8 It can be seen that the gate-source voltage of the seventh transistor T7 experiences a slow decrease and then remains stable, while the output current I... OUT After a slow increase, the current is maintained at a limited level, thus providing current-limiting protection. Because current is drawn from the first capacitor C1, the amplitude of the output voltage decreases slowly.
[0080] By implementing the fast current limiting circuit for a negative voltage linear regulator described in this application, the circuit efficiency is improved by directly comparing currents, eliminating error sources in traditional sampling methods, and achieving higher precision and faster current limiting. Simultaneously, the circuit structure is compact and easy to integrate. The current comparison module directly compares the detected current obtained from the output current through a current mirror structure, improving the response speed of the current comparison and reducing circuit power consumption. When the conversion current derived from the load current exceeds the current magnitude of the bias current source, the current feedback module intervenes to modulate the output current, quickly and accurately limiting the magnitude of the output current.
[0081] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.
[0082] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A fast current limiting circuit applied to a negative voltage linear regulator, characterized in that, include: Output module (100), current sampling module (200), current comparison module (300) and current feedback module (400); The current feedback module (400) includes a bias current source (I00). bias ); The output module (100) and the current sampling module (200) are both connected to the current comparison module (300), the current comparison module (300) is connected to the current feedback module (400), and the current feedback module (400) is connected to the output module (100) and the current sampling module (200). The current sampling module (200) detects the output current of the output module (100) to determine the detection current, and transmits the detection current to the current comparison module (300). The current comparison module (300) determines a first voltage at its connection point with the current feedback module (400) based on the detection current. The current feedback module (400) determines the voltage at which the conversion current generated by the first voltage is greater than the bias current source (I). bias When the provided current value is given, the increase in the amplitude of the output current is suppressed.
2. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 1, characterized in that, The output module (100) has: a first output module port (100a), a second output module port (100b), a third output module port (100c), and a fourth output module port (100d). The current sampling module (200) has: a first current sampling port (200a), a second current sampling port (200b), and a third current sampling port (200c). The current comparison module (300) has: a first current comparison port (300a), a second current comparison port (300b), a third current comparison port (300c), and a fourth current comparison port (300d). The current feedback module (400) has: a first current feedback port (400a), a second current feedback port (400b), a third current feedback port (400c), a fourth current feedback port (400d), and a fifth current feedback port (400e). The first port (100a) of the output module and the second port (200b) of the current sampling are used to connect the input voltage (V). IN The output module's second port (100b) is connected to the current comparison first port (300a) and is used to provide output current to the current comparison first port (300a). The output module's third port (100c) is connected to the current sampling first port (200a) and the current feedback third port (400c). The current sampling third port (200c) is connected to the current comparison second port (300b) and is used to transmit the detection current determined based on the output current. The current comparison third port (300c) is connected to the current feedback first port (400a). The current feedback second port (400b) is used to connect the adjustment current. The output module's fourth port (100d) is connected to the current comparison fourth port (300d) and the current feedback fourth port (400d) and then grounded. The current feedback fifth port (400e) is used to connect the input voltage (V). IN ).
3. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 2, characterized in that, The output module (100) includes: a first transistor (T1) and a first capacitor (C1); The source of the first transistor (T1) serves as the first port (100a) of the output module, the gate of the first transistor (T1) serves as the third port (100c) of the output module, the drain of the first transistor (T1) is connected to one end of the first capacitor (C1), and the other end of the first capacitor (C1) serves as the fourth port (100d) of the output module.
4. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 2, characterized in that, The current sampling module (200) includes a sampling transistor (T). S ); The sampling transistor (T) S The gate of the sampling transistor (T) serves as the first port (200a) for current sampling, and the sampling transistor (T) S The source of the current sampling terminal (200b) is used as the second port (200b) for connecting the input voltage (V). IN The sampling transistor (T) S The drain of the current sampler is used as the third port (200c).
5. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 2, characterized in that, The current comparison module (300) includes: a second transistor (T2), a third transistor (T3), a fourth transistor (T4), and a fifth transistor (T5); The gate of the second transistor (T2) is connected to the gate of the third transistor (T3), the drain of the third transistor (T3), and the drain of the fifth transistor (T5) to form the third port (300c) for current comparison. The source of the second transistor (T2) is connected to the source of the third transistor (T3) to form the fourth port (300d) for current comparison. The drain of the second transistor (T2) is connected to the drain of the fourth transistor (T4), the gate of the fourth transistor (T4), and the gate of the fifth transistor (T5). The source of the fourth transistor (T4) serves as the first port (300a) for current comparison, and the source of the fifth transistor (T5) serves as the second port (300b) for current comparison.
6. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 2, characterized in that, The current feedback module (400) includes: a sixth transistor (T6), a seventh transistor (T7), an eighth transistor (T8), a first resistor (R1), a second capacitor (C2), and a bias current source (I). bias ); The bias current source (I) bias One end of the bias current source (I) is connected to one end of the first resistor (R1) to serve as the fifth current feedback port (400e). bias The other end of the transistor is connected to the drain of the sixth transistor (T6), one end of the second capacitor (C2), and the gate of the seventh transistor (T7). The gate of the sixth transistor (T6) serves as the first current feedback port (400a). The source of the sixth transistor (T6) is connected to the other end of the second capacitor (C2) and serves as the fourth current feedback port (400d). The source of the seventh transistor (T7) serves as the second current feedback port (400b). The drain of the seventh transistor (T7) is connected to the drain of the eighth transistor (T8) and the gate of the eighth transistor (T8) and serves as the third current feedback port (400c). The source of the eighth transistor (T8) is connected to the other end of the first resistor (R1).
7. The fast current limiting circuit applied to a negative voltage linear regulator according to claim 1, characterized in that, The fast current limiting circuit applied to the negative voltage linear regulator also includes a voltage feedback module (500). The voltage feedback module (500) has: a voltage feedback first port (500a), a voltage feedback second port (500b), and a voltage feedback third port (500c); The voltage feedback first port (500a) is used to connect the output voltage (V). OUT The voltage feedback second port (500b) is connected to the current feedback second port (400b) of the current feedback module (400) and is used to provide adjustment current to the current feedback second port (400b). The voltage feedback third port (500c) is grounded.
8. The fast current limiting circuit for a negative voltage linear regulator according to claim 7, characterized in that, The voltage feedback module (500) includes: a voltage divider network (510), an operational amplifier (520), and a ninth transistor (T9); The voltage divider network (510) has: a first voltage divider network port (510a), a second voltage divider network port (520b), and a third voltage divider network port (510c). The first port (510a) of the voltage divider network serves as the first voltage feedback port (500a). The second port (520b) of the voltage divider network is connected to the source of the ninth transistor (T9) and serves as the third voltage feedback port (500c). The third port (510c) of the voltage divider network is connected to the non-inverting input of the operational amplifier (520), and the inverting input of the operational amplifier (520) is connected to a reference voltage (V). REF The output of the operational amplifier (520) is connected to the gate of the ninth transistor (T9), and the drain of the ninth transistor (T9) serves as the second voltage feedback port (500b).
9. The fast current limiting circuit for a negative voltage linear regulator according to claim 8, characterized in that, The voltage divider network (510) includes: a second resistor (R2) and a third resistor (R3); One end of the second resistor (R2) serves as the first port (510a) of the voltage divider network, and the other end of the second resistor (R2) is connected to one end of the third resistor (R3) to serve as the third port (510c) of the voltage divider network. The other end of the third resistor (R3) serves as the second port (520b) of the voltage divider network.
10. The fast current limiting circuit for a negative voltage linear regulator according to any one of claims 1-9, characterized in that, The input voltage of the fast current limiting circuit applied to the negative voltage linear regulator is lower than the ground potential.