Linear power supply circuit and linear power supply

Abstract

The invention discloses a linear power supply circuit and a linear power supply, the linear power supply circuit comprises a switch step-down circuit and a linear step-down circuit which are electrically connected in sequence, and the linear power supply circuit also comprises a feedback amplification circuit, the input end of the feedback amplification circuit is electrically connected with the output end of the switch step-down circuit and the output end of the linear step-down circuit at the same time, and the output end of the feedback amplification circuit is electrically connected with the feedback end of the switch step-down circuit. The linear power supply adopts the linear power supply circuit. The linear power supply circuit and the linear power supply not only can effectively reduce ripples of output voltage, but also are relatively high in efficiency, so that the probability of severe heating can be effectively reduced when the amplitude of voltage reduction is relatively large.

Description

Technical Field

[0001] The present application belongs to the technical field of linear power supply circuits, and in particular, relates to a linear power supply circuit and a linear power supply. Background Art

[0002] like Figure 1 As shown, the Chinese utility model patent (CN 203482106 U) provides a new linear power supply circuit, including a switching power supply circuit, a BUCK buck circuit, a linear buck circuit and an output circuit, wherein the output end of the switching power supply circuit is connected to the input end of the BUCK buck circuit, the output end of the BUCK buck circuit is connected to the input end of the linear buck circuit, and the output end of the linear buck circuit is connected to the input end of the output circuit. Since the BUCK buck circuit uses the switch conduction of the MOS tube to adjust the output voltage, although its output efficiency is high, the output voltage will have a large switching ripple, so its output voltage cannot be directly used in occasions where the output ripple requirements are relatively high. Therefore, the new linear power supply circuit uses a linear buck circuit to further reduce the voltage, so that a DC voltage with a smaller ripple can be obtained. However, the disadvantages of the linear buck circuit are also obvious, that is, its efficiency is relatively low, and when the amplitude of the voltage reduction is large, there will be serious heating, which is difficult to meet people's use needs. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the first invention object of the present application is to provide a linear power supply circuit, which can not only effectively reduce the ripple of the output voltage, but also has high efficiency, thereby effectively reducing the probability of severe heating when the voltage reduction amplitude is large; the second invention object of the present application is to provide a linear power supply using the above-mentioned linear power supply circuit.

[0004] In order to achieve the above first invention objective, the technical solution adopted in this application is as follows:

[0005] A linear power supply circuit comprises a switching buck circuit and a linear buck circuit which are electrically connected in sequence. The linear power supply circuit of the present application further comprises a feedback amplifier circuit, wherein the input end of the feedback amplifier circuit is electrically connected to the output end of the switching buck circuit and the output end of the linear buck circuit at the same time, and the output end of the feedback amplifier circuit is electrically connected to the feedback end of the switching buck circuit.

[0006] Furthermore, the switching buck circuit is a buck converter adopting a switching mode.

[0007] Preferably, the switching step-down circuit is a buck switching step-down circuit; the buck switching step-down circuit includes a DC buck U9 with a built-in MOS tube; the DC buck U9 is provided with a VSENSE end, the VSENSE end is the feedback end, and the VSENSE end is electrically connected to the output end of the feedback amplifier circuit.

[0008] Furthermore, the feedback amplifier circuit includes an operational amplifier U10, a switching buck circuit output sampling circuit and a linear buck circuit output sampling circuit; the operational amplifier U10 is provided with a first input terminal and a second input terminal; one end of the switching buck circuit output sampling circuit is connected to the output terminal of the switching buck circuit, and the other end is electrically connected to the first input terminal; one end of the linear buck circuit output sampling circuit is connected to the output terminal of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input terminal; the output terminal of the operational amplifier U10 is electrically connected to the feedback terminal.

[0009] Preferably, the switching buck circuit output sampling circuit includes a resistor R18 and a resistor R19, one end of the resistor R19 is electrically connected to the output end of the switching buck circuit, and the other end is connected in series with the resistor R18 and then grounded; the first input end is electrically connected to the connection position between the resistor R19 and the resistor R18; the linear buck circuit output sampling circuit includes a resistor R20, one end of the resistor R20 is electrically connected to the output end of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input end.

[0010] Furthermore, the linear step-down circuit is a step-down circuit constructed by triodes.

[0011] Preferably, the linear step-down circuit includes a PNP transistor Q11, a PNP transistor Q12 and an NPN transistor Q13; the collector of the PNP transistor Q11 is connected to the output end of the switching step-down circuit, and the base is connected to the collector of the PNP transistor Q12; the base of the PNP transistor Q12 is connected to the collector of the NPN transistor Q13; the emitters of the PNP transistor Q11, the PNP transistor Q12 and the NPN transistor Q13 are electrically connected to the base of the NPN transistor Q13 through a diode.

[0012] Furthermore, the linear power supply circuit of the present application also includes an output filter circuit; the input end of the output filter circuit is electrically connected to the output end of the linear buck circuit, and the output end of the output filter circuit is the output end of the linear power supply circuit.

[0013] Preferably, the output filter circuit includes a resistor R23, an inductor L6, a capacitor C12, a capacitor C13, a resistor R21, a capacitor C14 and a capacitor C16; the resistor R23 and the inductor L6 are connected in parallel to form a first parallel branch; the capacitor C12, the capacitor C13 and the resistor R21 are connected in parallel to form a second parallel branch; the capacitor C14 and the capacitor C16 are connected in parallel to form a third parallel branch; the input end of the second parallel branch and the input end of the first parallel branch are electrically connected to the output end of the linear step-down circuit, and the output end of the second parallel branch is grounded; the input end of the third parallel branch is connected to the output end of the second parallel branch, and the output end of the third parallel branch is grounded with the output end of the second parallel branch.

[0014] In order to achieve the above second invention objective, the technical solution adopted in this application is as follows:

[0015] A linear power supply comprises a body and a linear power supply circuit of any one of the above structures; the linear power supply circuit is electrically connected to the output end of the body.

[0016] Compared with the prior art, this application has at least the following beneficial effects:

[0017] The output voltage of the linear power supply circuit and linear power supply of the present application also needs to be linearly stepped down by a linear buck circuit, so the ripple is much smaller than that of the existing linear power supply circuit that only has a switch buck circuit. Moreover, the linear power supply circuit and linear power supply of the present application, because a feedback amplifier circuit is provided, the input end of the feedback amplifier circuit is electrically connected to the output end of the switch buck circuit and the output end of the linear buck circuit at the same time, and the output end of the feedback amplifier circuit is electrically connected to the feedback end of the switch buck circuit. The switch buck circuit is adjusted in real time through the feedback amplifier circuit, thereby achieving higher efficiency. When the amplitude of the voltage reduction is large, the probability of severe heating can be effectively reduced, meeting the user's usage needs.

[0018] The present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a circuit structure schematic diagram of an existing linear power supply circuit;

[0021] Figure 2 is a circuit structure diagram of a first exemplary embodiment of a linear power supply circuit of the present application;

[0022] Figure 3 is a circuit structure diagram of a second exemplary embodiment of the linear power supply circuit of the present application;

[0023] Figure 4 is a circuit structure diagram of a third exemplary embodiment of the linear power supply circuit of the present application;

[0024] Figure 5 yes Figure 4 Detailed circuit diagram. DETAILED DESCRIPTION

[0025] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] The term "comprise" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0028] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0029] In the embodiments of the present application, the terms “first”, “second”, etc. used are intended to be labels for distinguishing different elements, and may not necessarily have sequential meanings according to their numerical designations.

[0030] The embodiments of the present application are further described in detail below in conjunction with the drawings in the specification.

[0031] Embodiment 1

[0032] Figure 2 What is shown is a first exemplary embodiment of the linear power supply circuit of the present application, which includes a switching buck circuit and a linear buck circuit electrically connected in sequence. The linear power supply circuit of the present application also includes a feedback amplifier circuit, the input end of the feedback amplifier circuit is electrically connected to the output end of the switching buck circuit and the output end of the linear buck circuit at the same time, and the output end of the feedback amplifier circuit is electrically connected to the feedback end of the switching buck circuit.

[0033] The output voltage of the linear power supply circuit of the present application also needs to be linearly stepped down by a linear buck circuit, so the ripple is much smaller than that of the existing linear power supply circuit that only has a switch buck circuit. Moreover, the linear power supply circuit of the present application is provided with a feedback amplifier circuit, the input end of the feedback amplifier circuit is electrically connected to the output end of the switch buck circuit and the output end of the linear buck circuit at the same time, and the output end of the feedback amplifier circuit is electrically connected to the feedback end of the switch buck circuit. The switch buck circuit is adjusted in real time through the feedback amplifier circuit, thereby achieving higher efficiency. When the amplitude of the voltage reduction is large, the probability of severe heating can be effectively reduced, meeting the user's usage needs.

[0034] As an improvement of this embodiment, the switching buck circuit is a buck converter using a switching mode, which can help to further improve the output efficiency of the switching buck circuit.

[0035] Embodiment 2

[0036] Figure 3 The second exemplary embodiment of the linear power supply circuit of the present application is shown in FIG. Figure 2 Further improvements are made on the basis of the first exemplary embodiment shown, so the only difference between it and the above-mentioned first exemplary embodiment is that the linear power supply circuit described in this embodiment also includes an output filtering circuit; the input end of the output filtering circuit is electrically connected to the output end of the linear buck circuit, and the output end of the output filtering circuit is the output end of the linear power supply circuit, so that the output voltage after the buck is further filtered to obtain an output voltage with lower ripple.

[0037] Embodiment 3

[0038] Figure 4 and Figure 5 The third exemplary embodiment of the linear power supply circuit of the present application is shown in FIG. Figure 3The second exemplary embodiment is further improved on the basis of the second exemplary embodiment shown, so the only difference between it and the above second exemplary embodiment is:

[0039] The linear power supply circuit described in this embodiment also includes an intermediate filtering circuit; the intermediate filtering circuit is electrically connected between the switching buck circuit and the linear buck circuit, so that the output voltage of the switching buck circuit is further filtered before being input into the linear buck circuit, which helps to further reduce the overall ripple of the output voltage of the linear power supply circuit of the present application.

[0040] Specifically, Figure 5 As shown, the switch step-down circuit is a buck switch step-down circuit; the buck switch step-down circuit includes a DC power supply VCC, a resistor R6, a resistor R7, a capacitor C4, a resistor R8, a resistor R10, a capacitor C6, a capacitor C2, a capacitor C8, a DC step-down device U9 with a built-in MOS tube, a voltage regulator D1, and an inductor L4; wherein the DC step-down device U9 is provided with a VI N terminal (i.e., port 2), an EN terminal (i.e., port 3), a SS / TR terminal (i.e., port 4), a RT / CLK terminal (i.e., port 5), a COMP terminal (i.e., port 8), a PH terminal (i.e., port 10), a BOOT terminal (i.e., port 1), a VSENSE terminal (i.e., port 7), a PWRGD terminal (i.e., port 6), a TP terminal (i.e., port 11), and a GND terminal (i.e., port 9); the DC power supply VCC is divided into two branches, one of which is directly electrically connected to the VI N terminal, the other branch is connected in series with resistor R6 and resistor R7 in sequence and then grounded; the EN terminal is directly electrically connected to the connection point between resistor R6 and resistor R7; the SS / TR terminal is connected in series with capacitor C4 and directly grounded; the RT / CLK terminal is connected in series with resistor R8 and then grounded; the COMP terminal is divided into two branches, one of which is connected in series with resistor R10 and capacitor C6 and then grounded, and the other branch is connected in series with capacitor C2 and then grounded; the BOOT terminal is connected in series with capacitor C8 and then connected in parallel with the PH terminal, and then divided into two branches after parallel connection, one of which is connected in series with voltage regulator D1 and then grounded, and the other branch is connected in series with inductor L4 and then serves as the output end of the switching buck circuit; the PWRGD terminal is suspended; the TP terminal is connected to the GND terminal and then shared ground; the VSENSE terminal is the feedback terminal, and the VSENSE terminal is electrically connected to the output end of the feedback amplifier circuit.

[0041] Specifically, Figure 5 As shown, the feedback amplifier circuit includes a DC power supply VCC, a resistor R17, a resistor R15, an operational amplifier U10, a switching buck circuit output sampling circuit and a linear buck circuit output sampling circuit.

[0042] Among them, the operational amplifier U10 is provided with a first input terminal (i.e., interface 3), a second input terminal (i.e., interface 4), an output terminal (i.e., interface 1), a power supply terminal (i.e., interface 5), and a ground terminal (i.e., interface 2); the DC power supply VCC is connected in series with a short-circuit resistor R15 and then connected to the power supply terminal; the ground terminal is directly grounded; and the output terminal is connected to the VSENSE terminal.

[0043] One end of the switch buck circuit output sampling circuit is connected to the output end of the switch buck circuit, and the other end is electrically connected to the first input end; one end of the linear buck circuit output sampling circuit is connected to the output end of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input end; the output end of the operational amplifier is electrically connected to the feedback end, specifically: the switch buck circuit output sampling circuit includes a resistor R18 and a resistor R19, one end of the resistor R19 is electrically connected to the output end of the switch buck circuit, and the other end is connected in series with the resistor R18 and then grounded; the first input end is electrically connected to the connection position between the resistor R19 and the resistor R18; the linear buck circuit output sampling circuit includes a resistor R20, one end of the resistor R20 is electrically connected to the output end of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input end; one end of the resistor R17 is electrically connected to the second input end, and the other end is electrically connected to the output end of the operational amplifier U10.

[0044] As an improvement of this embodiment, the linear buck circuit is a buck circuit constructed by triodes. Since the buck circuit is a linear buck structure, it not only does not have switching noise, but also can effectively reduce the ripple of the output voltage. In order to further simplify the specific structure of the linear buck circuit and help reduce the production cost, as a further improvement of this embodiment, Figure 5 As shown, the linear step-down circuit includes a PNP transistor Q11, a PNP transistor Q12 and an NPN transistor Q13; the collector of the PNP transistor Q11 is connected to the output end of the switching step-down circuit, and the base is connected to the collector of the PNP transistor Q12; the base of the PNP transistor Q12 is connected to the collector of the NPN transistor Q13; the emitters of the PNP transistor Q11, the PNP transistor Q12 and the NPN transistor Q13 are electrically connected to the base of the NPN transistor Q13 through a diode D2 to serve as the output end of the linear step-down circuit.

[0045] As another improvement of this embodiment, the linear step-down circuit further includes an output regulating circuit, which is electrically connected to the output end of the linear voltage circuit, so as to adjust the output voltage value of the linear step-down circuit. In order to simplify the specific structure of the output regulating circuit, it is helpful to further reduce the production cost. Figure 5As shown, the output regulation circuit includes a resistor R22; the resistor R22 is connected in series to the base of the NPN transistor Q13; by changing the specific resistance value of the resistor R22, the output voltage value of the linear step-down circuit can be adjusted.

[0046] Specifically, in order to achieve the filtering function, such as Figure 5 As shown, the output filter circuit includes a resistor R23, an inductor L6, a capacitor C12, a capacitor C13, a resistor R21, a capacitor C14 and a capacitor C16; the resistor R23 and the inductor L6 are connected in parallel to form a first parallel branch; the capacitor C12, the capacitor C13 and the resistor R21 are connected in parallel to form a second parallel branch; the capacitor C14 and the capacitor C16 are connected in parallel to form a third parallel branch; the input end of the second parallel branch and the input end of the first parallel branch are electrically connected to the output end of the linear step-down circuit, and the output end of the second parallel branch is grounded; the input end of the third parallel branch is connected to the output end of the second parallel branch, and the output end of the third parallel branch is grounded with the output end of the second parallel branch.

[0047] Specifically, Figure 5 As shown, the intermediate filtering circuit includes a resistor R13, an inductor L5, a capacitor C9, a capacitor C10 and a capacitor C11; the resistor R13 and the inductor L5 are connected in parallel to form a fourth parallel branch; one end of the capacitor C10 and the capacitor C11, and the input end of the fourth parallel branch are electrically connected to the output end of the switching buck circuit, and the other end of the capacitor C10 and the capacitor C11 are grounded; the output end of the fourth parallel branch and one end of the capacitor C9 are electrically connected to the input end of the linear buck circuit, and the other end of the capacitor C9 is grounded.

[0048] Embodiment 5

[0049] The present application also discloses a linear power supply, comprising a main body and a linear power supply circuit having a structure as described in any one of the above embodiments; the linear power supply circuit is electrically connected to the output end of the main body.

[0050] The above-mentioned implementation modes are only preferred implementation modes of the present application and cannot be used to limit the scope of protection of the present application. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present application shall fall within the scope of protection required by the present application.

Claims

1. A linear power supply circuit, comprising a switching buck circuit and a linear buck circuit electrically connected in sequence, characterized in that: It also includes a feedback amplifier circuit, the input end of the feedback amplifier circuit is electrically connected to the output end of the switching buck circuit and the output end of the linear buck circuit at the same time, and the output end of the feedback amplifier circuit is electrically connected to the feedback end of the switching buck circuit.

2. The linear power supply circuit according to claim 1, characterized in that: The switching buck circuit is a buck converter using a switching mode.

3. The linear power supply circuit according to claim 2, characterized in that: The switching step-down circuit is a buck switching step-down circuit; the buck switching step-down circuit includes a DC buck U9 with a built-in MOS tube; the DC buck U9 is provided with a VSENSE terminal, the VSENSE terminal is the feedback terminal, and the VSENSE terminal is electrically connected to the output terminal of the feedback amplifier circuit.

4. The linear power supply circuit according to claim 1, characterized in that: The feedback amplifier circuit includes an operational amplifier U10, a switching buck circuit output sampling circuit and a linear buck circuit output sampling circuit; the operational amplifier U10 is provided with a first input terminal and a second input terminal; one end of the switching buck circuit output sampling circuit is connected to the output terminal of the switching buck circuit, and the other end is electrically connected to the first input terminal; one end of the linear buck circuit output sampling circuit is connected to the output terminal of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input terminal; the output terminal of the operational amplifier U10 is electrically connected to the feedback terminal.

5. The linear power supply circuit according to claim 4, characterized in that: The switching buck circuit output sampling circuit includes a resistor R18 and a resistor R19, one end of the resistor R19 is electrically connected to the output end of the switching buck circuit, and the other end is connected in series with the resistor R18 and then grounded; the first input end is electrically connected to the connection position between the resistor R19 and the resistor R18; the linear buck circuit output sampling circuit includes a resistor R20, one end of the resistor R20 is electrically connected to the output end of the linear buck circuit output sampling circuit, and the other end is electrically connected to the second input end.

6. The linear power supply circuit according to claim 1, characterized in that: The linear step-down circuit is a step-down circuit constructed by triodes.

7. The linear power supply circuit according to claim 6, characterized in that: The linear step-down circuit includes a PNP transistor Q11, a PNP transistor Q12 and an NPN transistor Q13; the collector of the PNP transistor Q11 is connected to the output end of the switching step-down circuit, and the base is connected to the collector of the PNP transistor Q12; the base of the PNP transistor Q12 is connected to the collector of the NPN transistor Q13; the emitters of the PNP transistor Q11, the PNP transistor Q12 and the NPN transistor Q13 are electrically connected to the base of the NPN transistor Q13 through a diode.

8. The linear power supply circuit according to claim 1, characterized in that: It also includes an output filter circuit; the input end of the output filter circuit is electrically connected to the output end of the linear step-down circuit, and the output end of the output filter circuit is the output end of the linear power supply circuit.

9. The linear power supply circuit according to claim 8, characterized in that: The output filter circuit includes a resistor R23, an inductor L6, a capacitor C12, a capacitor C13, a resistor R21, a capacitor C14 and a capacitor C16; the resistor R23 and the inductor L6 are connected in parallel to form a first parallel branch; the capacitor C12, the capacitor C13 and the resistor R21 are connected in parallel to form a second parallel branch; the capacitor C14 and the capacitor C16 are connected in parallel to form a third parallel branch; the input end of the second parallel branch and the input end of the first parallel branch are electrically connected to the output end of the linear step-down circuit, and the output end of the second parallel branch is grounded; the input end of the third parallel branch is connected to the output end of the second parallel branch, and the output end of the third parallel branch is grounded with the output end of the second parallel branch.

10. A linear power supply, characterized in that: It comprises a main body and a linear power supply circuit as described in any one of claims 1 to 9; the linear power supply circuit is electrically connected to the output end of the main body.

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