Low-power-consumption low-dropout linear regulator and circuit management system

Abstract

The invention discloses a low dropout linear regulator with low power consumption and a circuit management system, the low dropout linear regulator comprises a first switch circuit and a second switch circuit, the first switch circuit comprises a first switch tube and a second switch tube which are connected to a branch between a voltage source and a reference ground, and the second switch circuit comprises a third switch tube and a resistor unit which are connected. A series branch of the resistor unit is connected between the voltage source and the reference ground, and a low-voltage power supply signal is output at a common node of the resistor unit and the third switch tube. According to the scheme, the band-gap reference signal circuit and the LDO output voltage generation circuit are nested, and under the condition that the output voltage function of the LDO is achieved, good integration and better precision are achieved; and the output voltage can reach very low voltage output.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and more specifically to a low-power consumption low voltage difference linear regulator and a circuit management system. Background Art

[0002] Low Dropout Regulator (LDO) is widely used in electronic circuits, and is generally used to generate a DC voltage source that matches the load's expectations. With the advancement of technology, the design of LDO is moving towards lower power consumption, faster transient response, and higher integration. At the same time, in order to meet the needs of different applications, the parameters of LDO are also being optimized, such as improving the power supply rejection ratio (PSRR) and reducing quiescent current. Low-power LDO technology is an important branch in the field of power management. It plays a vital role in modern devices. As electronic devices become increasingly miniaturized and power-hungry, the performance requirements for LDO are also getting higher and higher, which has also promoted the continuous innovation and progress of LDO technology.

[0003] Existing common LDO systems such as Figure 1 As shown, it includes two parts. The first part provides a bandgap reference circuit for the reference voltage Vref. The second part includes a comparison circuit, a voltage modulation circuit and an output circuit. The output circuit generally includes a switch tube and a series resistor unit. The comparison circuit compares the reference voltage and the feedback signal. The voltage modulation circuit receives the input voltage Vin and the output signal of the comparison circuit, and controls the switch state of the switch tube in the output circuit with the output signal. The LDO output voltage signal is taken from the connection node signal of the switch tube and the series resistor unit. The existing LDO system circuit overall solution requires multiple modules to implement, and the overall power consumption is relatively large and the system cost is high. In some ultra-low power consumption applications, the LDO circuit itself must work in a low power consumption state, and the existing LDO architecture cannot meet the use of such occasions.

[0004] Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a low-power low-dropout linear regulator and a circuit management system to solve the technical problems of the prior art that the low-dropout linear regulator has high power consumption, high cost and insufficient output voltage.

[0006] Provided is a low-power low-voltage difference linear regulator, which receives a voltage from a voltage source to output an output electrical signal with driving capability, and comprises a first switch circuit and a second switch circuit, wherein the first switch circuit comprises a first switch tube and a second switch tube, both of which are connected between the voltage source and a reference ground, and the control ends of the first switch tube and the second switch tube are connected to each other, and the second switch circuit comprises a third switch tube and a voltage-dividing resistor unit connected, wherein a connecting branch of the third switch tube and the voltage-dividing resistor unit is connected between the voltage source and the reference ground, and the third switch tube is driven by a first drive signal, and the output electrical signal of the low-voltage difference linear regulator is output at a common node of the third switch tube and the voltage-dividing resistor unit, wherein the first drive signal is obtained after error amplification according to a first node signal of a branch where the first switch tube is located and a second node signal of a branch where the second switch tube is located.

[0007] Preferably, the first power terminal of the second switch tube is connected to the voltage source, and the second power terminal is connected to the reference ground through a first resistor, a second resistor and a second transistor connected in series; the first power terminal of the first switch tube is connected to the voltage source, and the second power terminal is connected to the reference ground through a third resistor and a first transistor connected in series.

[0008] Preferably, a common node to which the control terminals of the first switch tube and the second switch tube are connected is connected to a second power terminal of the first switch tube.

[0009] Preferably, a second driving circuit is included to provide a second driving signal, the second driving signal is used to drive the first switch tube and the second switch tube, and the second driving circuit is used to obtain the second driving signal according to the third node signal of the branch where the first switch tube is located and the fourth node signal of the branch where the second switch tube is located.

[0010] Preferably, the first power terminal of the third switching tube is connected to the voltage source, and the second power terminal is connected to the reference ground through the voltage-dividing resistor unit, the voltage-dividing resistor unit includes a first voltage-dividing resistor and a second voltage-dividing resistor, and the common connection end of the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the common connection end of the second switching tube and the second resistor, and the common connection end of the first voltage-dividing resistor and the second voltage-dividing resistor is used as a reference voltage signal.

[0011] Preferably, it includes a first driving circuit for providing a first driving signal, the first driving circuit includes a first error amplifier, the first error amplifier receives a first node signal and a second node signal to generate a first error signal, and the first error signal is transmitted to the control end of the third switching tube, wherein the first node signal is the common connection point voltage of the third resistor and the first transistor, and the second node signal is the common connection point voltage of the first resistor and the second resistor.

[0012] Preferably, the second error driving circuit further includes a buffer, which is connected between the output end of the first error amplifier and the control end of the third switch tube, wherein the gain of the buffer is unity gain.

[0013] Preferably, it further comprises a first capacitor, wherein a first end of the first capacitor is connected to a common connection point of the first resistor and the second resistor, and a second end of the first capacitor is connected to a common node of the third switch tube and the resistor unit.

[0014] Preferably, the first switch tube, the second switch tube and the third switch tube are all P-type transistors.

[0015] Preferably, the magnitude of the reference voltage signal is:

[0016] V FB =V BE +I R1 *R2

[0017] Among them, V BE is the base-emitter voltage of the first transistor, I R1 is the current flowing through resistor R1.

[0018] A circuit management system is also provided, comprising: at least one load module; and a low voltage dropout linear regulator as described above, used to provide a low voltage electrical signal with driving capability to the at least one load module according to a voltage source.

[0019] The low-power low-voltage difference linear regulator and circuit management system of the present invention include a first switch circuit and a second switch circuit, the first switch circuit includes a first switch tube and a second switch tube, both of which are connected to a branch between a voltage source and a reference ground, the first switch tube and the second switch tube control ends are connected to each other, the second switch circuit includes a third switch tube and a resistor unit connected, and its series branch is connected between the voltage source and the reference ground, the third switch tube is driven by a first drive signal, and a low-voltage power supply signal is output at a common node between the resistor unit and the third switch tube. Through the scheme of the present application, the bandgap reference signal circuit and the LDO output voltage generation circuit can have better integration and better accuracy by nesting in the case of realizing the output voltage function of the LDO; and the output voltage can achieve a very low voltage output. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A circuit block diagram of an LDO in the prior art;

[0021] Figure 2 A circuit diagram of a low-power low-dropout linear regulator according to the present invention;

[0022] Figure 3 According to the present invention Figure 2 A circuit diagram for realizing the first driving circuit in;

[0023] Figure 4 According to the present invention Figure 3 A specific circuit diagram of the error amplifier in . DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any substitution, modification, equivalent method and scheme made within the spirit and scope of the present invention.

[0025] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without these detailed descriptions.

[0026] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the accompanying drawings are all simplified and not in exact proportion, and are only used for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention.

[0027] refer to Figure 2 A circuit diagram of a low-power low-dropout linear regulator according to the present invention; Figure 3 According to the present invention Figure 2 A circuit diagram for realizing the first driving circuit in; Figure 4 According to the present invention Figure 3 A specific circuit diagram of the error amplifier in the embodiment of the present invention. The low-power low-dropout linear regulator of the present invention receives a voltage source voltage such as VDD to output an output electrical signal such as Vout with driving capability. Figure 2As shown, the low voltage difference linear regulator includes a first switch circuit and a second switch circuit, the first switch circuit includes a first switch tube MP1 and a second switch tube MP2, both connected between the voltage source and the reference ground, and the control ends of the first switch tube and the second switch tube are connected to each other; the second switch circuit includes a third switch tube MP0 and voltage-dividing resistor units RF1 and RF2, the connecting branch of the third switch tube and the voltage-dividing resistor unit is connected between the voltage source and the reference ground, and a first drive signal is generated by a first drive circuit to drive the third switch tube, and the output electrical signal Vout of the low voltage difference linear regulator is output at the common node of the third switch tube and the voltage-dividing resistor unit. Here, the first switch tube, the second switch tube and the third switch tube are all P-type transistors as an example, and those skilled in the art will know that they can also be other types of transistors, and any switch tube that can achieve the same function.

[0028] Specifically, the low voltage difference linear regulator also includes a first transistor Q1 and a second transistor Q2, the first power terminal of the second switch tube MP2 is connected to the voltage source VDD, and the second power terminal is connected to the reference ground through the first resistor R1, the second resistor R2 and the second transistor Q2 connected in series; the first power terminal of the first switch tube MP1 is connected to the voltage source VDD, and the second power terminal is connected to the reference ground through the third resistor R3 and the first transistor Q1 connected in series. In one example, the common node to which the control terminals of the first switch tube and the second switch tube are connected is connected to the second power terminal of the first switch tube MP1. Through this embodiment, when the drain voltage of MP1 is lower than the source voltage, the first switch tube and the second switch tube can be turned on. In another example, Figure 4 As shown, the low voltage difference linear regulator also includes a second drive circuit, which is used to provide a second drive signal VBP, and the second drive signal is used to drive the first switch tube and the second switch tube. The second drive circuit is used to obtain the second drive signal according to the third node signal of the branch where the first switch tube is located and the fourth node signal of the branch where the second switch tube is located. The second drive circuit can be an error circuit structure or other switch structure circuit that can generate a drive signal. This embodiment controls the switching state of the first switch tube and the second switch tube by feedback node signals, so that the opening of the first switch tube and the second switch tube is less affected by the matching degree of the first switch tube and the second switch tube, the temperature drift coefficient is good, and the control is more precise.

[0029] Specifically, refer to Figure 2 and Figure 3The first power terminal of the third switch tube MP0 in the low voltage difference linear regulator is connected to the voltage source VDD, and the second power terminal is connected to the reference ground through the voltage dividing resistor unit, the voltage dividing resistor unit includes a first voltage dividing resistor RF1 and a second voltage dividing resistor RF2, the common connection end of the first voltage dividing resistor and the second voltage dividing resistor is connected to the common connection end of the second switch tube MP2 and the second resistor R2, and the common connection end of the first voltage dividing resistor and the second voltage dividing resistor is used as a reference voltage signal V FB Specifically, the first driving circuit includes a first error amplifier, which generates the first driving signal to drive the third switch tube MP0, and the first error amplifier receives a first node signal and a second node signal to generate a first error signal, and the first error signal is transmitted to the control end of the third switch tube, wherein the first node signal is the common connection point voltage of the third resistor and the first transistor, and the second node signal is the common connection point voltage of the first resistor and the second resistor. Figure 3 As shown, the first input terminal of the error amplifier, such as the positive terminal, receives the first node signal VP1, and the second input terminal of the error amplifier, such as the negative terminal, receives the second node signal VN1. Figure 4 An embodiment of an error amplifier is shown. The error amplifier includes an operational amplifier composed of two N-type transistors MN1 and MN2, two P-type transistors MP3 and MP4, and a current source I1. The operational amplifier receives input signals VP1 and VN1 and generates an output signal Vy.

[0030] According to the circuit structure of the present application, the current flowing through the first resistor R1 is expressed as:

[0031] I R1 =△V BE / R1

[0032] Among them, △V BE is the voltage difference across resistor R1.

[0033] Furthermore, due to the op amp clamping effect of the first error amplifier AMP1, it can be known that the first node signal VP1 is equal to the second node signal VN1, and it can be known that the reference voltage signal V FB The size is:

[0034] V FB =V BE +I R1 *R2

[0035] Among them, VBE is the base-emitter voltage of the first transistor, and IR1 is the current flowing through resistor R1. The voltage expression of the final output voltage VOUT is:

[0036] V out=(1+R F1 / R F2 )*V FB

[0037] According to the output voltage formula, the output voltage of the present application can obtain a relatively low voltage signal. Generally speaking, the reference voltage signal V FB The value is about 1.2V. Thus, by reasonably configuring the sizes of the resistors RF1 and RF2, the output voltage of the present application can be controlled to be below 2V. This can expand the application occasions of LDO, especially in some low-voltage drive applications.

[0038] Through the above-mentioned first driving circuit, the overall driving ability of the LDO can be improved, and it can show sufficient driving ability and good driving effect for driving external loads such as large capacitive loads. The LDO of the present application is designed in a nested manner by a circuit for generating a reference signal and a circuit for generating a low-voltage power supply, so that the components of the device can be reduced, the overall power consumption will be lower, the efficiency is high, and a lower output voltage can be obtained, and the requirements for the voltage source VDD are also lower. It can be a higher voltage source or a lower voltage source, and the application is more flexible.

[0039] Continue to refer Figure 4 The first driving circuit further includes a buffer X1, which is connected between the output terminal of the first error amplifier and the control terminal of the third switch tube, wherein the gain of the buffer is unity gain. Adding a buffer facilitates stability compensation of the entire feedback system and improvement of transient response time.

[0040] Finally, the low voltage drop linear regulator further includes a first capacitor CFF, a first end of the first capacitor is connected to a common connection point of the first resistor and the second resistor, and a second end is connected to a common node of the third switch tube and the resistor unit. The first capacitor CFF is used to stabilize the output voltage Vout so that it maintains a stable value without being greatly deviated by the working state of the system.

[0041] Finally, the present application also provides a circuit management system, including at least one load module and the above-mentioned low voltage dropout linear regulator, which is used to provide a low voltage electrical signal with driving capability to at least one load module according to a voltage source. The circuit management system of the present application can drive the load module through a low-power LDO, which can improve the driving performance and efficiency of the overall system.

[0042] It should be noted that the specific implementation and corresponding illustrations given are merely a way of describing the implementation method of the present invention, and do not limit the specific structure of the implementation scheme of the present invention. Various changes or modifications can be made to these implementation schemes without departing from the principle and essence of the present invention, but these changes and modifications fall within the scope of protection of the present invention.

[0043] Although the embodiments are described and illustrated separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that the embodiments can be replaced and integrated. If the content is not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0044] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. A low-power low-dropout linear regulator, receiving a voltage from a voltage source to output an output electrical signal with driving capability, characterized in that: comprising a first switch circuit and a second switch circuit, The first switch circuit includes a first switch tube and a second switch tube, both of which are connected between the voltage source and the reference ground, and control ends of the first switch tube and the second switch tube are connected to each other. The second switch circuit includes a third switch tube and a voltage-dividing resistor unit connected, wherein a connecting branch between the third switch tube and the voltage-dividing resistor unit is connected between the voltage source and the reference ground, and the third switch tube is driven by a first drive signal, and an output electrical signal of the low voltage difference linear regulator is output at a common node between the third switch tube and the voltage-dividing resistor unit. The first driving signal is obtained after error amplification based on a first node signal of a branch where the first switch tube is located and a second node signal of a branch where the second switch tube is located.

2. The low voltage dropout linear regulator according to claim 1, characterized in that: The first power terminal of the second switch tube is connected to the voltage source, and the second power terminal is connected to the reference ground through a first resistor, a second resistor and a second transistor in series; The first power terminal of the first switch tube is connected to the voltage source, and the second power terminal is connected to the reference ground via a third resistor and the first transistor connected in series.

3. The low voltage dropout linear regulator according to claim 2, characterized in that: The common node to which the control terminals of the first switch tube and the second switch tube are connected is connected to the second power terminal of the first switch tube.

4. The low voltage dropout linear regulator according to claim 2, characterized in that: A second driving circuit is included to provide a second driving signal, wherein the second driving signal is used to drive the first switch tube and the second switch tube. The second driving circuit is used for obtaining the second driving signal according to a third node signal of the branch where the first switch tube is located and a fourth node signal of the branch where the second switch tube is located.

5. The low voltage dropout linear regulator according to claim 2, characterized in that: The first power terminal of the third switch tube is connected to the voltage source, and the second power terminal is connected to the reference ground through the voltage dividing resistor unit. The voltage-dividing resistor unit includes a first voltage-dividing resistor and a second voltage-dividing resistor, wherein a common connection end of the first voltage-dividing resistor and the second voltage-dividing resistor is connected to a common connection end of the second switch tube and the second resistor. A common connection terminal of the first voltage-dividing resistor and the second voltage-dividing resistor is used as a reference voltage signal.

6. The low voltage dropout linear regulator according to claim 5, characterized in that: comprising a first driving circuit for providing a first driving signal, The first driving circuit includes a first error amplifier, which receives a first node signal and a second node signal to generate a first error signal, and the first error signal is transmitted to a control terminal of the third switch tube. The first node signal is a voltage at a common connection point between the third resistor and the first transistor, and the second node signal is a voltage at a common connection point between the first resistor and the second resistor.

7. The low voltage dropout linear regulator according to claim 5, characterized in that: The second error driving circuit further includes a buffer, which is connected between the output terminal of the first error amplifier and the control terminal of the third switch tube. Wherein, the gain of the buffer is unity gain.

8. The low voltage dropout linear regulator according to claim 5, characterized in that: It also includes a first capacitor, a first end of which is connected to a common connection point of the first resistor and the second resistor, and a second end of which is connected to a common node of the third switch tube and the resistor unit.

9. The low dropout linear regulator according to claim 1, characterized in that: The first switch tube, the second switch tube and the third switch tube are all P-type transistors.

10. The low voltage dropout linear regulator according to claim 5, characterized in that: The magnitude of the reference voltage signal is: V FB =V BE +I R1 *R2 Among them, V BE is the base-emitter voltage of the first transistor, I R1 is the current flowing through resistor R1.

11. A circuit management system, characterized in that: include: at least one load module; The low voltage dropout linear regulator according to any one of claims 1 to 10 is used to provide a low voltage electrical signal with driving capability to at least one load module according to a voltage source.

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