A voltage regulating circuit and heat dissipation system

Abstract

The present application provides a voltage regulating circuit and a heat dissipation system voltage regulating circuit, comprising an input end and an output end, a first switch tube, a PWM power supply and a control unit, wherein the first switch tube is connected to a path between the input end and the output end; the PWM power supply outputs a PWM power supply voltage of a corresponding duty cycle based on a control instruction; the control unit is connected to the PWM power supply and the control end of the first switch tube, and the control unit is configured to generate a control current flowing through the control unit based on the PWM power supply voltage, and the control current flows through the control end of the first switch tube to control an output current flowing through the first switch tube and the output end. The above scheme can adjust the output voltage of the voltage regulating circuit by adjusting the duty cycle of the PWM voltage. Since PWM voltage regulation can achieve a smooth voltage regulation effect, the output voltage of the voltage regulating circuit can be smoothly regulated. When the voltage regulating circuit is connected to a DC motor fan, the voltage regulation range can be increased, so that the speed of the fan can be smoothly and accurately regulated.

Description

Technical Field

[0001] The disclosed embodiments of the present application relate to the field of radio frequency communication technology, and more specifically, to a voltage regulating circuit and a heat dissipation system. Background Art

[0002] With the development of electronic technology, more and more electronic products and application scenarios have higher demands on processor computing power. High-computing processors require more current, and the corresponding heat consumption will also increase significantly. The increase in temperature will cause the failure rate of electronic components to increase significantly, and an effective heat dissipation mechanism is needed at this time. When electronic products cannot completely dissipate heat through air heat conduction or metal casing, DC motor fan cooling is an effective heat dissipation method.

[0003] Most of the existing solutions change the fan speed by changing the DC fan motor input voltage through linear current and voltage regulation, or design several voltage levels to set the fan speed. For example, chip-level power supply relies on linear buck converter to achieve this, which is relatively expensive. In addition, the chip-level voltage range and regulation mechanism are fixed and difficult to change, and the application scenarios are limited. The solution using graded voltage speed regulation cannot accurately control the fan speed, and too high wind speed will cause excessive product noise. Utility Model Content

[0004] According to an embodiment of the present application, the present application provides a voltage regulating circuit and a heat dissipation system to alleviate at least one of the above-mentioned problems.

[0005] According to one aspect of the present application, an exemplary voltage regulating circuit is disclosed, including an input end and an output end, a first switch tube, a PWM power supply and a control unit, the first switch tube being connected to a path between the input end and the output end; the PWM power supply outputting a PWM power supply voltage of a corresponding duty cycle based on a control instruction; the control unit connecting the PWM power supply and the control end of the first switch tube, the control unit being configured to generate a control current flowing through the control unit based on the PWM power supply voltage, the control current flowing through the control end of the first switch tube to control an output current flowing through the first switch tube and the output end.

[0006] Among them, the control unit includes a control subunit and a feedback subunit, the control subunit is arranged between the control end of the first switch tube and the ground voltage; the feedback subunit is arranged between the first node between the first switch tube and the output end and the ground voltage; the control current flows through the control subunit.

[0007] In the above scheme, the feedback subunit provides a feedback signal to the control subunit, and the control subunit can then adjust the control current based on the feedback signal of the feedback subunit when the output voltage deviates, thereby adjusting the output voltage to improve the stability of the output voltage.

[0008] Wherein, the control subunit includes a second switch tube and a third switch tube, the control end of the second switch tube is connected to the PWM power supply, the first path end is connected to the ground, and the second path end is connected to the control end of the first switch tube; the control end of the third switch tube is connected to the feedback subunit, the first path end is connected to the ground, and the second path end is connected to the first node between the first switch tube and the output end.

[0009] In the above scheme, the magnitude of the control current is adjusted by the second switch tube and the third switch tube, thereby adjusting the magnitude of the output voltage, avoiding the use of chip-level voltage regulation, and reducing circuit costs.

[0010] Wherein, the first path ends of the second switch tube and the third switch tube are grounded through a common-pole resistor.

[0011] Wherein, the second switch tube and the third switch tube include triodes.

[0012] Wherein, the first switch tube includes a triode.

[0013] Wherein, the PWM power supply includes a first power supply, a second power supply and a fourth switch tube, the first power supply generates a PWM voltage with a corresponding duty cycle; the control end of the fourth switch tube is connected to the first power supply, the first path end is grounded, and the second path end is connected to the control unit; the first path end and the second path end of the fourth switch tube are selectively turned on or off based on the voltage of the first power supply; the second power supply is at least connected to the second path end of the fourth switch tube.

[0014] The above solution can improve the stability of the output voltage of the PWM power supply, thereby improving the output voltage stability of the voltage regulating circuit.

[0015] Wherein, it also includes a filtering unit connected between the PWM power supply and the control unit.

[0016] The above solution can further improve the stability of the output voltage of the PWM power supply through the filtering unit, thereby improving the output voltage stability of the voltage regulating circuit.

[0017] The feedback unit at least includes a first feedback resistor, a second feedback resistor and a feedback node, and the feedback node is connected to a common end of the first feedback resistor and the second feedback resistor.

[0018] In the above solution, the cost is further reduced by the feedback unit composed of feedback resistors.

[0019] A second aspect of the present application provides a heat dissipation system, comprising a heat dissipation fan and the voltage regulating circuit of the first aspect.

[0020] In the above scheme, a PWM voltage with a certain duty cycle is generated by a PWM power supply, and then a control unit generates a control current based on the PWM voltage and provides it to the control end of the first switch tube. The voltage at the output end of the voltage regulating circuit is controlled by the control current at the control end of the first switch tube, so that the output voltage of the voltage regulating circuit can be adjusted by adjusting the duty cycle of the PWM voltage, thereby increasing the voltage regulation range; since PWM voltage regulation can achieve the effect of smooth voltage regulation, the output voltage of the voltage regulating circuit can be smoothly regulated. When the voltage regulating circuit is connected to a DC motor fan, the speed of the fan can be adjusted steadily and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application will be further described below in conjunction with the accompanying drawings and implementation methods, in which:

[0022] Figure 1 It is a schematic diagram of a framework of an embodiment of a voltage regulating circuit of the present application;

[0023] Figure 2 is a circuit structure diagram of another embodiment of the voltage regulating circuit of the present application;

[0024] Figure 3 It is a schematic diagram of the framework of an embodiment of the heat dissipation system of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present application, the technical solution of the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0026] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "said", and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless otherwise clearly indicated above, and "multiple" generally includes at least two, but does not exclude the inclusion of at least one.

[0027] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0028] It should be understood that the terms "include", "comprises" or any other variations used herein are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0029] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The presence of the phrase at each location in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0030] Please refer to Figure 1 , Figure 1 It is a schematic diagram of a framework of an embodiment of a voltage regulating circuit of the present application; the voltage regulating circuit 100 includes an input terminal VIN and an input terminal VOUT, a first switch tube Q1, a PWM power supply 120 and a control unit 110, the first switch tube Q1 is connected to the path between the input terminal VIN and the input terminal VOUT; the PWM power supply 120 outputs a PWM power supply voltage of a corresponding duty cycle based on a control instruction; the control unit 110 is connected to the PWM power supply 120 and the control terminal of the first switch tube Q1, and the control unit 110 is configured to generate a control current flowing through the control unit 110 based on the PWM power supply voltage, and the control current flows through the control terminal of the first switch tube Q1 to control the output current flowing through the first switch tube Q1 and the input terminal VOUT.

[0031] In the above scheme, a PWM voltage with a certain duty cycle is generated by the PWM power supply 120, and then the control unit 110 generates a control current based on the PWM voltage and provides it to the control end of the first switch tube Q1. The voltage of the input end VOUT of the voltage regulating circuit 100 is controlled by the control current of the control end of the first switch tube Q1, so that the output voltage of the voltage regulating circuit 100 can be adjusted by adjusting the duty cycle of the PWM voltage, thereby increasing the voltage regulation range; because PWM voltage regulation can achieve the effect of smooth voltage regulation, the output voltage of the voltage regulating circuit 100 can be smoothly regulated. When the voltage regulating circuit 100 is connected to a DC motor fan, the speed of the fan can be adjusted steadily and accurately.

[0032] In some embodiments, the first switch tube Q1 may include a field effect tube or a triode; for example, Figure 1 As shown, the first switch tube Q1 can be a PNP type triode, the emitter of the first switch tube Q1 is connected to the input terminal VIN, the collector is connected to the input terminal VOUT, the base is connected to the control unit 110, and the first switch tube Q1 works in the amplification state. The PWM power supply 120 provides the PWM power supply voltage to the control unit 110, and the control unit 110 generates a control current according to the PWM power supply voltage and provides it to the base of the first switch tube Q1. The first switch tube Q1 works in the amplification state, and the current of the collector of the first switch tube Q1 is controlled by the control current received by the base of the first switch tube Q1. The output voltage of the voltage regulation circuit 100 can be adjusted by adjusting the duty cycle of the PWM power supply voltage. The duty cycle adjustment of the PWM power supply voltage can be adjusted by a control instruction, so it is conducive to the convenience of voltage regulation.

[0033] In some embodiments, please refer to Figure 2 , Figure 2 is a circuit structure diagram of another embodiment of the voltage regulating circuit of the present application; Figure 2 As shown, the control unit 110 may further include a control subunit 111 and a feedback subunit 112; the control subunit 111 is arranged between the control end of the first switch tube Q1 and the ground voltage, and the feedback subunit 112 is arranged between the first node P1 between the first switch tube Q1 and the input end VOUT and the ground voltage; the control current flows through the control subunit 111.

[0034] In this embodiment, the feedback subunit 112 can obtain the output voltage of the collector of the first switch tube Q1, and obtain the feedback current based on the output voltage of the collector of the first switch tube Q1, and provide the feedback current to the control subunit 111 through the feedback node P2. The control subunit 111 adjusts the magnitude of the control current according to the feedback current, and then adjusts the output voltage of the collector of the first switch tube Q1, thereby achieving the effect of feedback regulation. Therefore, through the voltage feedback of the feedback subunit 112, when the output voltage is offset, it can be corrected in time, thereby improving the stability of the output voltage.

[0035] In some embodiments, please refer to Figure 2 , the control subunit 111 may include a second switch tube Q2 and a third switch tube Q3. The control end of the second switch tube Q2 is connected to the PWM power supply 120, the first channel end is connected to the ground, and the second channel end is connected to the control end of the first switch tube Q1; the control end of the third switch tube Q3 is connected to the feedback subunit 112, the first channel end is connected to the ground, and the second channel end is connected to the first node P1 between the first switch tube Q1 and the input end VOUT.

[0036] It should be noted that the control end of the switching tube can refer to the base of a transistor, the gate of a field effect tube, etc., the first path end of the switching tube can be the collector or emitter of a transistor, the source or drain of a field effect tube, etc., and the second path end can be the collector or emitter of a transistor, the source or drain of a field effect tube, etc.; the control end, the first path end, and the second path end are not limited to a certain terminal of the switching tube. For example, when the conduction or cutoff of the switching tube is controlled by the voltage or current on two terminals, the control end of the switching tube should include the above two terminals.

[0037] exist Figure 2In the illustrated embodiment, the second switch tube Q2 and the third switch tube Q3 are triodes for illustration; when the second switch tube Q2 and the third switch tube Q3 are both triodes, a better temperature compensation effect is achieved. The base of the second switch tube Q2 is connected to the PWM power supply 120, and the collector is connected to the base of the first switch tube Q1; the base of the third switch tube Q3 is connected to the feedback node P2 of the feedback subunit 112, and the collector is connected to the collector of the first switch tube Q1; the emitters of the second switch tube Q2 and the third switch tube Q3 are grounded through the common resistor R1. The resistance value of the common resistor R1 needs to be selected according to the load current and load voltage characteristics. By adjusting the duty cycle of the PWM power supply 120, the control current output by the collector of the second switch tube Q2 can be adjusted, so that the base of the first switch tube Q1 controls the output current of the collector of the first switch tube Q1 according to the control current, so as to adjust the output voltage of the voltage regulation circuit 100. Driven by a PWM power signal with a certain duty cycle, the voltage across the common resistor R1 is also certain, and is equal to the base voltage of the second switch tube Q2 minus the emitter junction voltage of the second switch tube Q2.

[0038] Continue to refer to Figure 2 , the feedback unit may include a first feedback resistor R2 and a second feedback resistor R3, and the feedback node P2 is connected to the common end of the first feedback resistor R2 and the second feedback resistor R3. One end of the first feedback resistor R2 is connected to the first node P1, and the other end is connected to the second feedback resistor R3; one end of the second feedback resistor R3 is connected to the first feedback resistor R2, and the other end is grounded. The voltage division of the first feedback resistor R2 and the second feedback resistor R3 is used to detect the change of the output voltage of the input terminal VOUT of the voltage regulating circuit 100. When the output voltage increases or decreases, the negative feedback introduced by the first feedback resistor R2 and the second feedback resistor R3 will correspondingly adjust the emitter current of the third switch tube Q3 to control the amplified current of the collector of the second switch tube Q2. The change of the amplified current of the collector of the second switch tube Q2 will cause the change of the base current of the first switch tube Q1, thereby adjusting the output voltage. Therefore, when the output voltage fluctuates, the output can be quickly adjusted to the set value through the negative feedback regulation of the feedback unit.

[0039] In addition, the output voltage can be adjusted by adjusting the resistance ratio of the first feedback resistor R2 to the second feedback resistor R3. The first feedback resistor R2 is connected to the collector of the first switch tube Q1, so that the voltage between the base and the emitter of the first switch tube Q1 can be limited to prevent the first switch tube Q1 from being damaged.

[0040] It should be noted that the connection method of the resistor of the feedback subunit 112 is not limited to Figure 2In the connection method shown in the illustrated embodiment, the number of feedback resistors is not limited to two, and the negative feedback regulation function can be achieved by connecting multiple resistors in series or in parallel, and the present application does not limit this.

[0041] In some embodiments, the PWM power supply 120 may include a first power supply V1, a second power supply V2 and a fourth switch tube Q4. The first power supply V1 is used to generate a PWM voltage with a corresponding duty cycle, thereby adjusting the voltage output by the PWM power supply 120 to the base of the second switch tube Q2.

[0042] In some embodiments, a filtering unit may also be included. Figure 2 As shown, the filter unit may include a filter resistor R4 and a filter capacitor C1, and a low-pass filter composed of the fourth switch tube Q4, the filter resistor R4 and the filter capacitor C1 is used to realize the digital-to-analog conversion function. The capacitance of the filter capacitor C1 needs to be selected according to the input voltage of the input terminal VIN and the load characteristics.

[0043] The second aspect of the present application provides a heat dissipation system, please refer to Figure 3 , Figure 3 It is a schematic diagram of the framework of an embodiment of the heat dissipation system of the present application; specifically, the heat dissipation system 300 includes a heat dissipation fan 310 and the voltage regulating circuit 100 of the first aspect described above.

[0044] In the above scheme, a PWM voltage with a certain duty cycle is generated by the PWM power supply 120, and then the control unit 110 generates a control current based on the PWM voltage and provides it to the control end of the first switch tube Q1. The voltage of the input end VOUT of the voltage regulating circuit 100 is controlled by the control current of the control end of the first switch tube Q1, so that the output voltage of the voltage regulating circuit 100 can be adjusted by adjusting the duty cycle of the PWM voltage, thereby increasing the voltage regulation range; because PWM voltage regulation can achieve the effect of smooth voltage regulation, the output voltage of the voltage regulating circuit 100 can be smoothly regulated. When the voltage regulating circuit 100 is connected to a DC motor fan, the speed of the fan can be adjusted steadily and accurately.

[0045] It is easy for a person skilled in the art to know that many modifications and changes can be made to the device and method while maintaining the teaching content of the present application. Therefore, the above disclosure should be considered as limited only by the scope of the appended claims.

Claims

1. A voltage regulating circuit, characterized in that: include: Input and output terminals; A first switch tube, connected to the path between the input end and the output end; A PWM power supply outputs a PWM power supply voltage with a corresponding duty cycle based on a control instruction; A control unit is connected to the PWM power supply and the control end of the first switch tube, and the control unit is configured to generate a control current flowing through the control unit based on the PWM power supply voltage, and the control current flows through the control end of the first switch tube to control the output current flowing through the first switch tube and the output end.

2. The circuit according to claim 1, characterized in that The control unit comprises: A control subunit, arranged between the control terminal of the first switch tube and the ground voltage; A feedback subunit, arranged between a first node between the first switch tube and the output terminal and the ground voltage; Wherein, the control current flows through the control subunit.

3. The circuit according to claim 2, characterized in that The control subunit comprises: a second switch tube, wherein a control end of the second switch tube is connected to the PWM power supply, a first path end is connected to the ground, and a second path end is connected to the control end of the first switch tube; A third switch tube, wherein a control end of the third switch tube is connected to the feedback subunit, a first path end is connected to the ground, and a second path end is connected to a first node between the first switch tube and the output end.

4. The circuit according to claim 3, characterized in that The first channel ends of the second switch tube and the third switch tube are grounded through a common-pole resistor.

5. The circuit according to claim 3 or 4, characterized in that: The second switch tube and the third switch tube include triodes.

6. The circuit according to claim 5, characterized in that The first switch tube includes a triode.

7. The circuit according to claim 1, characterized in that The PWM power supply comprises: A first power supply generates a PWM voltage with a corresponding duty cycle; a fourth switch tube, a control end of which is connected to the first power supply, a first path end of which is grounded, and a second path end of which is connected to the control unit; the first path end and the second path end of the fourth switch tube are selectively turned on or off based on the voltage of the first power supply; The second power source is at least connected to the second path end of the fourth switch tube.

8. The circuit according to claim 7, characterized in that Also includes: A filtering unit is connected between the PWM power supply and the control unit.

9. The circuit according to claim 2, characterized in that The feedback subunit at least includes: A first feedback resistor; A second feedback resistor; A feedback node is connected to a common end of the first feedback resistor and the second feedback resistor.

10. A heat dissipation system, comprising a heat dissipation fan, characterized in that: It also includes the voltage regulating circuit described in any one of claims 1-9.

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