A power supply circuit and adapter

Abstract

The present invention relates to the field of power supply design technology, and in particular to a power supply circuit and an adapter. The power supply circuit includes: a main circuit module; a current mirror module, the input end of the current mirror module is connected to the output end of the main circuit module, and is used to sample the output current of the main circuit module; and a control module, the control module is connected to the output end of the current mirror module, and is used to adjust the output power of the main circuit module according to the sampled output current. Since the current mirror module does not require power from an external power supply when it is working, and it can adapt to the sampling of high and low voltages, the power supply circuit has the characteristics of low power consumption and a wide voltage sampling range.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply design, and in particular to a power supply circuit and an adapter. Background Art

[0002] Generally, conventional power supply devices are provided with a sampling circuit, which can sample the excitation output by the power supply device and feed it back to the power supply device so that the power supply device can output stable and reliable excitation.

[0003] In the process of implementing the present invention, the inventors found that the conventional technology has at least the following problems: the sampling circuit provided by the conventional power supply device generally uses an operational amplifier or a chip as the acquisition end, which requires power from an external power supply to work, so its power consumption is relatively high. Moreover, when it is necessary to sample the high-end voltage, the operational amplifier or the chip is limited by the power supply voltage and cannot meet the sampling needs of the high-end voltage, so the application range of its sampling voltage is relatively narrow. Summary of the invention

[0004] An object of an embodiment of the present invention is to provide a power supply circuit and an adapter, which solve the technical problems of low power consumption and narrow application range of sampling voltage in traditional technologies.

[0005] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a power supply circuit, comprising: a main circuit module; a current mirror module, an input end of the current mirror module is connected to an output end of the main circuit module, and is used to sample an output current of the main circuit module; and a control module, the control module is connected to the output end of the current mirror module, and is used to adjust the output power of the main circuit module according to the sampled output current.

[0007] Optionally, the main circuit module is configured with two positive voltage output paths and a ground loop path shared by the two positive voltage output paths; the input end of the current mirror module is connected to the two positive voltage output paths.

[0008] Optionally, the current mirror module includes at least two current mirror units; the input end of one current mirror unit is connected to one of the positive voltage output paths, and the output end of one of the current mirror units is connected to the control module; the input end of another current mirror unit is connected to another of the positive voltage output paths, and the output end of another current mirror unit is connected to the control module.

[0009] Optionally, the current mirror unit includes: a current conversion circuit, used for sampling and converting the output current flowing through the positive voltage output path; and a mirror current source circuit, used for mirroring the converted output current and outputting the mirror current.

[0010] Optionally, the current mirror unit further includes: a negative feedback circuit, used for adjusting the mirror current.

[0011] Optionally, one of the positive voltage output paths is used to output a 48 volt voltage; and another of the positive voltage output paths is used to output a 12 volt voltage.

[0012] Optionally, the power supply circuit also includes: a dynamic dummy load module, which includes two input terminals, one input terminal of the dynamic dummy load module is connected to one positive voltage output path, and the other input terminal of the dynamic dummy load module is connected to another positive voltage output path, and is used to automatically add a load when the output voltage of the main circuit module is greater than a preset threshold.

[0013] Optionally, the control module includes: a comparison circuit, used to generate a comparison result based on the sampled output current and a preset threshold; and a control circuit, used to adjust the output power of the main circuit module according to the comparison result.

[0014] Optionally, the main circuit module includes: an EMC circuit, an input end of the EMC circuit is used for an external power supply; a rectifier circuit, an input end of the rectifier circuit is connected to an output end of the EMC circuit; a PFC circuit, an input end of the PFC circuit is connected to an output end of the rectifier circuit; a resonant circuit, an input end of the resonant circuit is connected to an output end of the PFC circuit, and an output end of the resonant circuit is used to output voltage and current.

[0015] In a second aspect, an embodiment of the present invention provides an adapter, wherein the adapter includes any one of the power supply circuits.

[0016] In the power supply circuit provided by various embodiments of the present invention, the current mirror module samples the output current of the main circuit module, and the control module adjusts the output power of the main circuit module according to the sampled output current, so that the power supply circuit can operate in the limited power mode required by the safety regulations or in the expected working state. Since the current mirror module does not require power from an external power supply when it is working, and it can adapt to the sampling of high and low voltages, the power supply circuit has the characteristics of low power consumption and a wide voltage sampling range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 is a circuit principle block diagram of a power supply circuit provided by an embodiment of the present invention;

[0019] Figure 2 is a circuit principle block diagram of a control module provided by an embodiment of the present invention;

[0020] Figure 3 is a circuit principle block diagram of a power supply circuit provided by another embodiment of the present invention;

[0021] Figure 4 is a circuit principle block diagram of a power supply circuit provided by yet another embodiment of the present invention;

[0022] Figure 5 is a circuit principle block diagram of a power supply circuit provided by yet another embodiment of the present invention;

[0023] Figure 6 is a circuit principle block diagram of a power supply circuit provided by yet another embodiment of the present invention;

[0024] Figure 7 is a circuit principle block diagram of a power supply circuit provided by yet another embodiment of the present invention;

[0025] Figure 8 is a circuit principle block diagram of a power supply circuit provided by yet another embodiment of the present invention;

[0026] Fig. 9 A circuit principle block diagram of a main circuit module provided by an embodiment of the present invention;

[0027] Fig.10 It is a circuit structure diagram of an EMC circuit, a rectifier circuit, and a PFC circuit in a main circuit module provided by an embodiment of the present invention;

[0028] Fig.11 is a circuit structure diagram of a resonant circuit in a main circuit module provided by an embodiment of the present invention;

[0029] Fig.12 It is a schematic diagram of a partial circuit structure of a control module provided by an embodiment of the present invention;

[0030] Fig.13 is a schematic diagram of another circuit structure of a control module provided by an embodiment of the present invention;

[0031] Fig.14is a circuit structure diagram of a comparison circuit provided by an embodiment of the present invention;

[0032] Fig.15 is a schematic diagram of a circuit structure of a current mirror module provided by an embodiment of the present invention;

[0033] Fig.16 is a circuit structure schematic diagram of a current conversion circuit provided by an embodiment of the present invention;

[0034] Fig.17 is a schematic diagram of a circuit structure of a current mirror unit provided by an embodiment of the present invention;

[0035] Fig.18 The present invention provides a circuit structure diagram of a dynamic dummy load module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] The power supply circuit provided in the embodiment of the present invention can be applied to various power supply devices, such as adapters, LED power supplies, etc.

[0038] See also Figure 1 , Figure 1 FIG. 1 is a circuit principle block diagram of a power supply circuit provided by an embodiment of the present invention. Figure 1 As shown, the power supply circuit 100 includes: a main circuit module 11 , a current mirror module 12 and a control module 13 .

[0039] An input end of the current mirror module 12 is connected to an output end of the main circuit module 11 , and the control module 13 is connected to an output end of the current mirror module 12 .

[0040] The main circuit module 11 is used for responding to the input of the external power supply and converting the external power supply into a desired output voltage or output current, which can be a single-channel output, a dual-channel output, or even a multi-channel output.

[0041] The current mirror module 12 is used to sample the output current of the main circuit module 11, and the control module 13 adjusts the output power of the main circuit module 11 according to the sampled output current. For example, when the output current of the main circuit module 11 is greater than the preset current threshold, the control module 13 reduces the output current of the main circuit module 11 according to the sampled output current, so that the output current of the main circuit module 11 is maintained within the expected current value range. Alternatively, when the output current of the main circuit module 11 is less than the preset current threshold, the control module 13 maintains the current working state of the main circuit module 11.

[0042] In some embodiments, when the control module 13 adjusts the main circuit module 11, it can adjust directly according to the sampling result, or it can make a comparison based on the sampling result before adjusting. Figure 2 As shown, the control module 13 includes: a comparison circuit 131 and a control circuit 132 .

[0043] The comparison circuit 131 is used to generate a comparison result based on the sampled output current and the preset threshold. The user can customize the preset threshold for the comparison circuit 131 according to the product design, for example, the preset threshold is 2.5 volts. The control circuit 132 is used to adjust the output power of the main circuit module 11 according to the comparison result.

[0044] In summary, since the current mirror module 12 does not require external power supply when working, and it can adapt to the sampling of high and low voltages, the power supply circuit 100 has the characteristics of low power consumption, wide voltage sampling range, simple structure and low cost.

[0045] like Figure 3 As shown, the main circuit module 11 is configured with two positive voltage output paths and a ground loop path shared by the two paths, and the input end of the current mirror module 12 is connected to the two positive voltage output paths. Since the power supply circuit 100 has dual outputs, in order to better sample the output current corresponding to each path, the input end of the current mirror module 12 can be connected to the two positive voltage output paths to sample the output current corresponding to each path respectively, so that the subsequent circuit can accurately distinguish the working state of each path.

[0046] In some embodiments, the main circuit module 11 can output 48 volts and 12 volts respectively through two positive voltage output paths, for example: one positive voltage output path is used to output 48 volts, and the other positive voltage output path is used to output 12 volts. When the current mirror module 12 is used to sample the output current of the positive voltage output path loaded with 48 volts, the current mirror module 12 can complete the sampling work under the high-end voltage of 48 volts. For conventional technology, the operational amplifiers or chips currently available on the market cannot meet the sampling requirements of 48 volts, and the maximum sampling voltage that can be accepted is 36 volts. Therefore, the current mirror module 12 provided in this embodiment can realize sampling work under the high-end voltage.

[0047] In some embodiments, Figure 4 As shown, the power supply circuit 100 further includes a dynamic dummy load module 14. The dynamic dummy load module 14 includes two input terminals, one input terminal of the dynamic dummy load module 14 is connected to a positive voltage output path, and the other input terminal of the dynamic dummy load module 14 is connected to another positive voltage output path.

[0048] The dynamic dummy load module 14 is used to automatically add a load when the output voltage of the main circuit module 11 is greater than a preset threshold. For example, when the output voltage of a positive voltage output path of the main circuit module 11 is greater than 48V or 12V, the dynamic dummy load module 14 automatically adds a load to the power supply circuit 100 to pull down the output voltage and prevent the output voltage from floating high.

[0049] Based on the consideration of sampling the output current more efficiently and accurately, in some embodiments, as Figure 5 As shown, the current mirror module 12 includes at least two current mirror units 121, the input end of one current mirror unit 121 is connected to a positive voltage output path, and the output end of one current mirror unit 121 is connected to the control module 13. The input end of another current mirror unit 121 is connected to another positive voltage output path, and the output end of another current mirror unit 121 is connected to the control module 13.

[0050] One current mirror unit 121 can sample the output current flowing through one positive voltage output path, and another current mirror unit 121 can sample the output current flowing through another positive voltage output path. The control module 13 can adjust the main circuit module 11 according to the sampling results of the current mirror unit 121 corresponding to each positive voltage output path.

[0051] However, in some embodiments, based on safety standards, for example, in order to meet the LPS (Limited Power Source) safety standard in a single failure mode, such as Figure 6 As shown, the current mirror module 12 includes four current mirror units 121, and each positive voltage output path is configured with two current mirror units 121. During the sampling process, when a current mirror unit 121 on a specific positive voltage output path fails, another current mirror unit 121 on the specific positive voltage output path takes over the sampling work, thereby ensuring that the power supply circuit 100 can work reliably and stably.

[0052] In some embodiments, Figure 7 As shown, the current mirror unit 121 includes: a current conversion circuit 1211 and a mirror current source circuit 1212. The input end of the current conversion circuit 1211 is connected to the corresponding positive voltage output path, the output end of the current conversion circuit 1211 is connected to the input end of the mirror current source circuit 1212, and the output end of the mirror current source circuit 1212 is connected to the control module 13.

[0053] The current conversion circuit 1211 is used to sample and convert the output current flowing through the positive voltage output path. Generally, the output current flowing through the positive voltage output path is relatively large. In order to facilitate the detection and analysis of the subsequent circuit, the current conversion circuit 1211 can convert the output current flowing through the positive voltage output path into a relatively small current, and establish a linear function relationship between the output current and the converted current.

[0054] The mirror current source circuit 1212 is used to mirror the output current after conversion and output the mirror current. The control module 13 adjusts the output power of the main circuit module 11 according to the mirror current.

[0055] In some embodiments, Figure 8 As shown, the current mirror unit 121 also includes a negative feedback circuit 1213, and the negative feedback circuit 1213 is connected to the mirror current source circuit 1212. The negative feedback circuit 1213 is used to adjust the mirror current. Generally, when external factors cause the mirror current source circuit 1212 to work unstably, for example: excessively high temperature causes the switch tube of the mirror current source circuit 1212 to change, causing the mirror current to increase. Therefore, the negative feedback circuit 1213 adjusts the mirror current source circuit 1212 according to the increased mirror current, so that the mirror current source circuit 1212 reduces the increased mirror current and reduces it to the expected current value, thereby improving the sampling accuracy.

[0056] In the above embodiments, those skilled in the art can design the main circuit module 11 according to product requirements. Fig. 9 As shown, the main circuit module 11 includes: an EMC circuit 111 , a rectifier circuit 112 , a PFC circuit 113 and a resonant circuit 114 .

[0057] The input end of the EMC circuit 111 is used for an external power supply, the input end of the rectifier circuit 112 is connected to the output end of the EMC circuit 111, the input end of the PFC circuit 113 is connected to the output end of the rectifier circuit 112, the input end of the resonant circuit 114 is connected to the output end of the PFC circuit 113, and the output end of the resonant circuit 114 is used to output voltage and current.

[0058] The EMC circuit 111 receives external power, filters out interference from some clutter signals, and outputs power after EMC processing to the next stage circuit.

[0059] The rectifier circuit 112 converts the EMC-processed power into a DC power and transmits it to the next stage circuit.

[0060] The PFC circuit 113 performs power factor correction processing on the DC power supply and transmits the processed DC power supply to the next stage circuit.

[0061] The resonant circuit 114 steps down the voltage of the DC power supply after power factor correction, and outputs the stepped-down output voltage to the load. The resonant circuit 114 can output multiple voltages through multiple positive voltage paths.

[0062] Therefore, the main circuit module 11 provided in this embodiment has the advantages of good electromagnetic compatibility, high power factor, and multi-channel output.

[0063] In order to explain the purpose of the embodiment of the present invention in detail, the embodiment of the present invention Figures 10 to 18 The working principle of the detailed power supply circuit is as follows:

[0064] Please also read Fig.10 and Fig.11 The main circuit module 11 includes: an EMC circuit 111, a rectifier circuit 112, a PFC circuit 113 and a resonant circuit 114.

[0065] The control module 13 can adjust the frequency or duty cycle of the resonant circuit 114 according to the sampled output current, thereby adjusting the output power of the main circuit module 11 .

[0066] Please refer to Fig.12 and Fig.13 The control module 13 includes: a comparison circuit 131 and a control circuit 132. The comparison circuit 131 is used to generate a comparison result according to the sampled output current and the preset threshold. The control circuit 132 is used to adjust the output power of the main circuit module 11 according to the comparison result. Among them, the control circuit 132 includes a controller and peripheral circuits.

[0067] In order to explain the working principle of the comparison circuit 131 in detail, this embodiment will Fig.13 The comparison circuit U9 is extracted as an example for introduction. Fig.14 , U9 has a preset voltage of 2.5V. When the voltage at the R end is greater than 2.5V, the transistor is turned on, that is, the C pin and the A pin of U9 are turned on.

[0068] Therefore, in this embodiment, the sampled output current is converted into a voltage and loaded on the R terminal, so as to achieve the purpose of comparison.

[0069] See also Fig.15 The current mirror module 12 includes four current mirror units 121 , two current mirror units 121 are configured for the positive voltage output path that outputs a 48 volt voltage, and two current mirror units 121 are configured for the positive voltage output path that outputs a 12 volt voltage.

[0070] In order to explain the working principle of the current mirror unit in detail, this embodiment will Fig.15A current mirror unit is used as an example. In order to detect the current I1 flowing through R46, it is necessary to set a current conversion circuit 1211 to perform linear conversion on the current I1. Fig.16 , has the following formula:

[0071] R46*I1=R83*I2

[0072] Then I2=I1*R46 / R83, I2≈I3.

[0073] See also Fig.17 According to the working principle of the mirror current source, I3=Ic3+2Ib, Ib is very small and can be ignored, so I3≈Ic3≈Ic4≈Ic5, that is, I5≈I3+I4≈2*I2≈2*(I1*R46 / R83). V0=I5*R50=2*(I1*R46 / R83)*R50. When the voltage V0 reaches 2.5V, the feedback loop is triggered and the protection is started. In addition, the voltage V0 can be adjusted by adjusting the resistors R46, R83, and R50, so that the control module 13 adjusts the output power of the main circuit module 11 according to the voltage V0.

[0074] Please refer again Fig.15 , corresponding to the current mirror unit 121 of 48 volts, when the excessive temperature causes the switch tube of the mirror current source circuit 1212 to change, so that the mirror current increases, due to its high-end sampling, the error generated by the increased mirror current is relatively large. Therefore, the negative feedback circuit 1213 composed of the resistor bridge network R69, R71, R70 and R72 can negatively feedback and adjust the voltage drop between the base and emitter of the switch tube E2 in U15, thereby reducing the base current, and then reducing the emitter current, that is, reducing the mirror current. Of course, the negative feedback circuit 1213 can also be applied to the current mirror unit 121 corresponding to the 12 volt voltage, and the application scope of the negative feedback circuit 1213 is not limited here.

[0075] See also Fig.18, the dynamic dummy load module 14 is composed of a number of resistors and a comparator U4. Since the power supply circuit 100 has dual outputs, when one output is empty or lightly loaded, the output voltage corresponding to the other positive voltage path may float high, thereby affecting the working stability of the power supply circuit 100. For example: when the output voltage corresponding to the 48-volt positive voltage path floats high, so that the voltage drop across the resistor R80 is greater than the preset threshold voltage of 2.5 volts of the comparator U4, then the C terminal and the A terminal are turned on. Therefore, the dynamic dummy load module 14 is added to the power supply circuit 100 as a dummy load to prevent the output voltage from continuing to float high. Similarly, when the output voltage corresponding to the 12-volt positive voltage path floats high, its working principle can refer to the above content and will not be repeated here. Similarly, the dynamic dummy load module 14 can not only adapt to two output voltages, but also adapt to three or more output voltages.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power supply circuit, characterized in that: include: A main circuit module, wherein the main circuit module is configured with two positive voltage output paths and a ground loop path shared by the two; A current mirror module, the input end of which is connected to the two positive voltage output paths and is used to sample the output current of the main circuit module; A control module, the control module is connected to the output end of the current mirror module and is used to adjust the output power of the main circuit module according to the sampled output current; The control module includes a comparison circuit and a control circuit. The comparison circuit is used to generate a comparison result based on the sampled output current and a preset threshold value. The control circuit is used to adjust the output power of the main circuit module based on the comparison result.

2. The power supply circuit according to claim 1, characterized in that: The current mirror module includes at least two current mirror units; An input end of the current mirror unit is connected to one of the positive voltage output paths, and an output end of the current mirror unit is connected to the control module; An input end of another current mirror unit is connected to another positive voltage output path, and an output end of another current mirror unit is connected to the control module.

3. The power supply circuit according to claim 2, characterized in that: The current mirror unit comprises: A current conversion circuit, used for sampling and converting an output current flowing through the positive voltage output path; The mirror current source circuit is used for mirroring the output current after conversion and outputting the mirror current.

4. The power supply circuit according to claim 3, characterized in that: The current mirror unit also includes: A negative feedback circuit is used to adjust the mirror current.

5. The power supply circuit according to claim 1, characterized in that: One of the positive voltage output paths is used to output a 48 volt voltage; The other positive voltage output path is used to output a 12 volt voltage.

6. The power supply circuit according to claim 1, characterized in that: The power supply circuit also includes: A dynamic dummy load module comprises two input terminals, one input terminal of the dynamic dummy load module is connected to one positive voltage output path, and the other input terminal of the dynamic dummy load module is connected to another positive voltage output path, and is used for automatically adding a load when the output voltage of the main circuit module is greater than a preset threshold.

7. The power supply circuit according to any one of claims 1 to 6, characterized in that: The main circuit module comprises: An EMC circuit, wherein an input end of the EMC circuit is used for an external power supply; A rectifier circuit, wherein an input end of the rectifier circuit is connected to an output end of the EMC circuit; A PFC circuit, wherein an input end of the PFC circuit is connected to an output end of the rectifier circuit; A resonant circuit, wherein the input end of the resonant circuit is connected to the output end of the PFC circuit, and the output end of the resonant circuit is used to output voltage and current.

8. An adapter, characterized in that: Comprising a power supply circuit as claimed in any one of claims 1 to 7.

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