linear voltage regulator

Abstract

The application provides a linear voltage stabilizer, which comprises: a main voltage stabilizing circuit; a sub voltage stabilizing circuit connected in parallel with the main voltage stabilizing circuit, and the current load capacity of the sub voltage stabilizing circuit is less than that of the main voltage stabilizing circuit; wherein the main voltage stabilizing circuit is used for being turned on when the load current exceeds a set threshold value, and being turned off when the load current does not exceed the set threshold value. In this way, by the design strategy of turning on or turning off the main voltage stabilizing circuit, when the load current is low, the characteristic of the sub voltage stabilizing circuit for consuming extremely low static current is utilized, so as to reduce the static current consumption of the linear voltage stabilizer as a whole when the load current is low, and adapt to rapid switching of the load.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and more specifically to a linear voltage regulator. Background Technology

[0002] refer to Figure 1 A conventional linear regulator includes an error amplifier 1 and a power transistor 2. The error amplifier 1 adjusts the operating state of the power transistor 2, thereby stabilizing the output voltage VOUT to the set target value. It has the advantages of low cost and low noise.

[0003] In conventional linear regulators, the maximum current load capacity is directly proportional to the size of the power transistor. A large current load capacity requires a large power transistor. To drive a large power transistor and maintain the large loop bandwidth required for fast transient response, the error amplifier needs a correspondingly large quiescent current. However, under small load current conditions, a large quiescent current leads to additional power consumption. Summary of the Invention

[0004] To address the problems in the prior art, the present invention aims to provide a linear regulator that can reduce the static current consumption of the linear regulator under low load current.

[0005] This invention provides a linear voltage regulator, comprising:

[0006] Main voltage regulator circuit;

[0007] The secondary voltage regulator circuit is connected in parallel with the primary voltage regulator circuit. The current load capacity of the secondary voltage regulator circuit is less than that of the primary voltage regulator circuit.

[0008] The main voltage regulator circuit is used to turn on when the load current exceeds a set threshold and turn off when the load current does not exceed the set threshold.

[0009] Optionally, the main voltage regulator circuit includes a main error amplifier and a main power transistor;

[0010] The secondary voltage regulator circuit includes a secondary error amplifier and a secondary power transistor;

[0011] The main voltage regulator circuit and the secondary voltage regulator circuit share a feedback circuit, and the output of the feedback circuit serves as the output of the linear regulator.

[0012] The first main input terminal of the main error amplifier and the first secondary input terminal of the secondary error amplifier are both used to input the reference voltage. The second main input terminal of the main error amplifier and the second secondary input terminal of the secondary error amplifier are both connected to the input terminal of the feedback circuit. The output terminal of the main error amplifier is connected to the gate of the main power transistor, and the output terminal of the secondary error amplifier is connected to the gate of the secondary power transistor.

[0013] The output of the feedback circuit is connected to the output of both the main power transistor and the secondary power transistor.

[0014] The input terminals of both the main power transistor and the auxiliary power transistor are used to input the input voltage;

[0015] The main voltage regulator circuit is specifically used to turn on the main voltage regulator circuit when the current of the secondary power transistor exceeds the current threshold, and to turn off the main voltage regulator circuit when the current of the secondary power transistor does not exceed the current threshold.

[0016] Optionally, the linear regulator also includes:

[0017] The current detection circuit is used to detect the current of the secondary power transistor and turn on the main voltage regulator circuit when the current of the secondary power transistor exceeds the current threshold, and turn off the main voltage regulator circuit when the current of the secondary power transistor does not exceed the current threshold.

[0018] Optionally, the current detection circuit includes:

[0019] Current sensing tube, used to detect the current of the secondary power tube;

[0020] The comparator is used to detect the current of the input current sensing tube, and turns on the main voltage regulator circuit when the detected current causes the input voltage to exceed the reference voltage, and turns off the main voltage regulator circuit when the detected current causes the input voltage to not exceed the reference voltage.

[0021] Optionally, the comparator is connected to the main error amplifier, specifically for sending a control signal to the main error amplifier. The control signal is used to turn the main voltage regulator circuit on or off.

[0022] Optionally, the number of main power transistors in the main voltage regulator circuit is greater than the number of secondary power transistors in the secondary voltage regulator circuit.

[0023] Optionally, the current load capacity of the main voltage regulator circuit is many times that of the secondary voltage regulator circuit.

[0024] The linear regulator provided by this invention has the following advantages:

[0025] In this invention, the linear regulator may include: a main voltage regulator circuit; and a secondary voltage regulator circuit connected in parallel with the main voltage regulator circuit, wherein the current load capacity of the secondary voltage regulator circuit is less than that of the main voltage regulator circuit. The main voltage regulator circuit is configured to turn on when the load current exceeds a set threshold and turn off when the load current does not exceed the set threshold. Thus, by using a design strategy of turning the main voltage regulator circuit on or off, the extremely low quiescent current consumption of the secondary voltage regulator circuit is utilized when the load current is low, thereby reducing the overall quiescent current consumption of the linear regulator at low load currents and adapting to rapid load switching. Attached Figure Description

[0026] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0027] Figure 1 The circuit diagram is for a linear regulator based on related technologies.

[0028] Figure 2 A schematic diagram of the circuit principle of the linear regulator provided in the embodiments of this disclosure;

[0029] Figure 3 A specific circuit diagram of a linear regulator provided in one embodiment of this disclosure;

[0030] Figure 4 A detailed circuit diagram of a linear regulator provided for yet another embodiment of this disclosure. Detailed Implementation

[0031] The following specific examples illustrate the implementation methods of this application. Those skilled in the art can easily understand the other advantages and effects of this application from the content disclosed herein. This application can also be implemented or applied through other different specific embodiments, and various details in this application can be modified or changed according to different viewpoints and application systems without departing from the spirit of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the application. This application may be embodied in many different forms and is not limited to the embodiments described herein.

[0033] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics represented in connection with that embodiment or example, which are included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics represented may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate different embodiments or examples represented in this application, as well as features of different embodiments or examples.

[0034] Furthermore, the terms "first" and "second" are used for illustrative purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the representation of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0035] To clearly illustrate this application, devices unrelated to the description are omitted, and the same or similar constituent elements throughout the specification are given the same reference numerals.

[0036] Throughout this specification, when it is said that a device is "connected" to another device, this includes not only "direct connection" but also "indirect connection" by placing other components in between. Furthermore, when it is said that a device "comprises" a certain constituent element, unless otherwise stated otherwise, this does not exclude other constituent elements, but rather implies that other constituent elements may be included.

[0037] When we say that a device is "above" another device, this can mean that it is directly above the other device, or it can mean that other devices are present in between. Conversely, when we say that a device is "directly" "above" another device, there are no other devices present in between.

[0038] Although the terms first, second, etc., are used in some instances herein to refer to various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, first interface and second interface, etc., are used. Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are interpreted as inclusive, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0039] The technical terms used herein are for reference only to specific embodiments and are not intended to limit the scope of this application. The singular form used herein includes the plural form unless the statement explicitly indicates otherwise. The word "comprising" as used in the specification means to specify a particular characteristic, region, integer, step, operation, element, and / or component, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0040] Although not explicitly defined, all terms, including technical and scientific terms used herein, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Terms defined in commonly used dictionaries shall be further interpreted as having a meaning consistent with the relevant technical literature and the content of this present application, and shall not be over-interpreted as having an ideal or overly formulaic meaning unless otherwise defined.

[0041] Figure 2 This is a circuit diagram of a linear regulator provided in an embodiment of the present disclosure. The linear regulator includes:

[0042] Main voltage regulator circuit 21;

[0043] The secondary voltage regulator circuit 22 is connected in parallel with the main voltage regulator circuit 21. The current load capacity of the secondary voltage regulator circuit 22 is less than that of the main voltage regulator circuit 21.

[0044] The main voltage regulator circuit 21 is used to turn on when the load current exceeds a set threshold and to turn off when the load current does not exceed the set threshold.

[0045] In this way, by turning the main voltage regulator circuit 21 on or off, when the load current is low, the characteristic of the secondary voltage regulator circuit consuming extremely low quiescent current is utilized to reduce the overall quiescent current consumption of the linear regulator at low load current and adapt to rapid load switching.

[0046] like Figure 3 As shown, the main voltage regulator circuit 31 includes a main error amplifier 311 and a main power transistor 312;

[0047] The secondary voltage regulator circuit 32 includes a secondary error amplifier 321 and a secondary power transistor 322;

[0048] The main voltage regulator circuit 31 and the secondary voltage regulator circuit 32 share the feedback circuit 33, and the output terminal of the feedback circuit 33 serves as the output terminal of the linear regulator.

[0049] The first main input terminal of the main error amplifier 311 and the first secondary input terminal of the secondary error amplifier 321 are both used to input the reference voltage VR. The second main input terminal of the main error amplifier 311 and the second secondary input terminal of the secondary error amplifier 321 are both connected to the input terminal of the feedback circuit 33. The output terminal of the main error amplifier 311 is connected to the gate of the main power transistor 312, and the output terminal of the secondary error amplifier 321 is connected to the gate of the secondary power transistor 322.

[0050] The output terminal of feedback circuit 33 is connected to the output terminal of main power transistor 312 and the output terminal of auxiliary power transistor 322;

[0051] The input terminals of both the main power transistor 312 and the auxiliary power transistor 322 are used to input the input voltage;

[0052] The main voltage regulator circuit 31 is specifically used to turn on the main voltage regulator circuit 31 when the current of the secondary power transistor 322 exceeds the current threshold, and to turn off the main voltage regulator circuit 31 when the current of the secondary power transistor 322 does not exceed the current threshold.

[0053] Figure 3 This diagram illustrates the circuit structure of the main voltage regulator circuit 31 and the secondary voltage regulator circuit 32, as well as the electrical connections between the components. The main error amplifier 311 and the main power transistor 312 form the main loop, i.e., the main voltage regulator circuit 31. The secondary error amplifier 321 and the secondary power transistor 322 form the secondary loop, i.e., the secondary voltage regulator circuit 32. The current load capacity of the main loop is several times that of the secondary loop, and the quiescent current consumption of the main loop is also several times that of the secondary loop. Furthermore, the main loop has a larger multi-loop bandwidth than the secondary loop, which can accommodate rapid load changes.

[0054] To reduce the total quiescent current, the main loop is closed under low load current conditions. The quiescent current of the secondary loop is very small, and it continuously monitors the current of the secondary power transistor. When the current of the secondary power transistor exceeds a set threshold, the main loop is activated, providing the majority of the load current capability. In this way, the linear regulator can meet the requirements of ultra-low quiescent current under low load current conditions and high current load capability and ultra-fast response under high load current conditions.

[0055] Using this embodiment, when the main voltage regulator circuit 31 is turned on, since the main voltage regulator circuit 31 and the secondary voltage regulator circuit 32 are connected in parallel, they simultaneously provide load current capability, enabling a rapid response to requirements.

[0056] In other embodiments of this disclosure, the secondary voltage regulator circuit may be turned off while the primary voltage regulator circuit is turned on.

[0057] In this embodiment, the number of main power transistors 312 in the main voltage regulator circuit 31 is greater than the number of secondary power transistors 322 in the secondary voltage regulator circuit 32. This allows the main voltage regulator circuit 31 to provide a larger load current capability, while the secondary voltage regulator circuit 32 can provide an appropriate small load current capability.

[0058] Continue to refer to Figure 3 Linear regulators also include:

[0059] The current detection circuit 34 is used to detect the current of the secondary power transistor 322, and to turn on the main voltage regulator circuit when the current of the secondary power transistor 322 exceeds the current threshold, and to turn off the main voltage regulator circuit when the current of the secondary power transistor does not exceed the current threshold.

[0060] This embodiment employs a secondary power transistor current detection circuit 34. It uses a design strategy of turning the main error amplifier 311 and the main power transistor 312 on or off according to the current threshold of the secondary power transistor 322. By utilizing the characteristic of the secondary error amplifier 321 consuming extremely low quiescent current, it ensures the overall current load capacity of the linear regulator while greatly reducing the overall quiescent current consumption of the linear regulator at low load current and adapting to rapid load switching.

[0061] In this embodiment of the disclosure, a current detection circuit or switching device may also be designed outside the linear regulator to control the opening and closing of the main regulator circuit.

[0062] In this embodiment of the disclosure, reference is made to Figure 4 The current detection circuit includes:

[0063] The current sensing tube 411 is used to detect the current of the auxiliary power tube 42;

[0064] Comparator 412 is used to detect the current of input current sensing tube 411, and turns on the main voltage regulator circuit 43 when the detected current causes the input voltage to exceed the reference voltage, and turns off the main voltage regulator circuit 43 when the detected current causes the input voltage to not exceed the reference voltage.

[0065] The current detection circuit 41 consists of a current detection transistor 411 (whose size is proportional to that of the secondary power transistor 42), a current source, and a comparator 412. The secondary power transistor 42 and the current detection transistor 411 have the same driving voltage, and the current of the secondary power transistor 42 can be proportionally reflected in the current detection transistor 411. If the output current of the linear regulator changes from small to large, the current of the current sensing transistor 411 will also change from small to large. When the current of the sensing transistor is larger than the current of the set current source, the positive input voltage of the comparator 412 will become high. When the positive input voltage of the comparator 412 becomes much higher than the reference voltage (V1) input, the comparator flips and turns on the main voltage regulator circuit 43. If the output current of the linear regulator changes from large to small, the current of the current sensing transistor 411 will also change from large to small. When the current of the current sensing transistor 411 is smaller than the current of the set current source, the positive input voltage of the comparator 412 will become low. When the positive input voltage of the comparator 412 becomes much lower than the reference voltage (V1) input, the comparator 412 will flip again and turn off the main voltage regulator circuit 43.

[0066] The current detection circuit 41 in this embodiment is unique and simple, and can quickly detect the current, enabling the linear regulator to have ultra-fast and stable main voltage regulator circuit turn-on and turn-off capabilities, thereby meeting the ultra-fast (e.g., 1µs) response speed of the linear regulator from no load to full load, and the output drop usually does not exceed 2% of the output voltage.

[0067] In this embodiment, comparator 412 is connected to main error amplifier 431 and is specifically used to send a control signal to main error amplifier 431. The control signal is used to turn main voltage regulator circuit 43 on or off.

[0068] In the embodiments of this disclosure, the linear regulator is a low-loss linear regulator or a low-saturation linear regulator (LDO), which is a linear regulator that can operate even with a low input-output potential difference.

[0069] The linear regulator of this disclosure can be used in an on-board computer ECU (Electronic Control Unit).

[0070] With the development of automotive electronics, especially new energy vehicles, in order to reduce energy consumption, when the ECU (Electronic Control Unit) in a car is not in use, it is put into a sleep state with low current consumption. In the sleep state, the information before the ECU went to sleep needs to be effectively and error-free. At this time, the ECU power supply needs to consume as little current as possible (down to tens of uA) while maintaining the necessary output voltage accuracy. When the ECU needs to be used, the ECU needs to be woken up quickly (down to 1 uS) (including the MCU on the ECU). At this time, the power supply of the ECU also needs to respond quickly, so that the LDO output voltage drop cannot be too much, usually not more than 2% of the output voltage. Since the installation space of a large part of the ECU is limited, it is not possible to meet the requirements by increasing the capacitor.

[0071] The linear regulator provided in this embodiment has an ultra-fast loop response speed, which can meet the needs of ECUs for ultra-fast, large-amplitude dynamic current changes and high-precision power supply.

[0072] Furthermore, the current sensing circuit can adapt to the LDO load current and automatically adjust the LDO's quiescent current, thereby enabling the LDO to have ultra-low quiescent current consumption under low current load, which greatly extends the standby time of the ECU system, especially the battery standby time when the vehicle is parked for a long time, and significantly saves energy.

[0073] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A linear voltage regulator, characterized in that, include: The main voltage regulator circuit includes a main error amplifier and a main power transistor. A secondary voltage regulator circuit is connected in parallel with the primary voltage regulator circuit. The current load capacity of the secondary voltage regulator circuit is less than that of the primary voltage regulator circuit. The secondary voltage regulator circuit includes a secondary error amplifier and a secondary power transistor. A current detection circuit is used to detect the current of the secondary power transistor, and to turn on the main voltage regulator circuit when the current of the secondary power transistor exceeds a current threshold, and to turn off the main voltage regulator circuit when the current of the secondary power transistor does not exceed the current threshold. The main voltage regulator circuit is configured to turn on when the load current exceeds a set threshold and turn off when the load current does not exceed the set threshold. The current detection circuit includes: A current sensing tube is used to detect the current of the secondary power tube; A comparator is used to input the detection current of the current sensing tube, and to turn on the main voltage regulator circuit when the detection current causes the input voltage to exceed the reference voltage, and to turn off the main voltage regulator circuit when the detection current causes the input voltage to not exceed the reference voltage. The comparator is connected to the main error amplifier and is specifically used to send a control signal to the main error amplifier. The control signal is used to turn the main voltage regulator circuit on or off.

2. The linear voltage regulator according to claim 1, characterized in that, The main voltage regulator circuit and the secondary voltage regulator circuit share a feedback circuit, and the output terminal of the feedback circuit serves as the output terminal of the linear regulator. Wherein, the first main input terminal of the main error amplifier and the first secondary input terminal of the secondary error amplifier are both used to input the reference voltage, the second main input terminal of the main error amplifier and the second secondary input terminal of the secondary error amplifier are both connected to the input terminal of the feedback circuit, the output terminal of the main error amplifier is connected to the gate of the main power transistor, and the output terminal of the secondary error amplifier is connected to the gate of the secondary power transistor; The input terminal of the feedback circuit is connected to the output terminal of the main power transistor and the output terminal of the auxiliary power transistor. The input terminals of both the main power transistor and the auxiliary power transistor are used to input the input voltage; The main voltage regulator circuit is specifically used to turn on the main voltage regulator circuit when the current of the secondary power transistor exceeds the current threshold, and to turn off the main voltage regulator circuit when the current of the secondary power transistor does not exceed the current threshold.

3. The linear voltage regulator according to claim 1, characterized in that, The number of main power transistors in the main voltage regulator circuit is greater than the number of secondary power transistors in the secondary voltage regulator circuit.

4. The linear voltage regulator according to claim 1, characterized in that, The current load capacity of the main voltage regulator circuit is many times that of the secondary voltage regulator circuit.

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