A low power consumption power adapter circuit
By designing an LLC converter circuit unit and utilizing zero-voltage turn-on and zero-current turn-off technologies, the problems of complex power adapter circuits and high power consumption are solved, achieving low-power, high-efficiency power conversion, which is suitable for low-cost power adapter circuits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN XINGUANCHENG ELECTRONIC TECH CO LTD
- Filing Date
- 2025-06-13
- Publication Date
- 2026-06-16
AI Technical Summary
Existing power adapters have complex circuit structures, high costs, and high power consumption, which affect the user experience and safety of electronic devices.
The LLC converter circuit unit, including components such as a first resistor, a second resistor, a capacitor, and a field-effect transistor, reduces switching losses through zero-voltage turn-on and zero-current turn-off. Combined with the design of inductors and capacitors, it achieves high-efficiency power conversion.
It reduces switching losses, improves the efficiency of the charging circuit, and keeps the adapter operating efficiently over a wide load range. It also has the advantages of simple circuit structure and low cost.
Smart Images
Figure CN224367736U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power adapter technology, and in particular to a low-power power adapter circuit. Background Technology
[0002] Power adapters, as crucial components connecting electronic devices to external power sources, are ubiquitous in our daily lives. Whether it's appliances in our homes or devices like mobile phones and rechargeable batteries, all require a suitable adapter to convert high-voltage AC mains power into the low-voltage DC power needed by the device. The performance and quality of power adapters directly impact the user experience and safety of electronic devices, thus placing higher demands on their performance, functionality, and safety. Existing power adapters suffer from complex circuitry, high cost, and high power consumption. Utility Model Content
[0003] The technical problem solved by this utility model is to provide a low-power power adapter circuit that is simple in structure, low in cost, and low in power consumption.
[0004] This utility model provides a low-power power adapter circuit, including a controller, a transformer, and an LLC converter circuit unit electrically connected to the transformer. The LLC converter circuit unit includes a first resistor, a second resistor, a first capacitor, a second capacitor, a first diode, a first field-effect transistor, and a second field-effect transistor. A first terminal of the first resistor is electrically connected to the source of the first field-effect transistor, and a second terminal of the first resistor is electrically connected to the gate of the first field-effect transistor. A first terminal of the second resistor is electrically connected to the second terminal of the first resistor, and a second terminal of the second resistor is electrically connected to the controller.
[0005] The first terminal of the first capacitor is electrically connected to the source of the first field-effect transistor (FET), and the second terminal of the first capacitor is electrically connected to the drain of the first FET. The first terminal of the second capacitor is electrically connected to the source of the second FET, and the second terminal of the second capacitor is electrically connected to the drain of the second FET. The first diode is connected in parallel with the second resistor. The source of the first FET is electrically connected to the first terminal of the transformer. The source of the second FET is grounded, the drain of the second FET is electrically connected to the source of the first FET, and the gate of the second FET is electrically connected to the controller.
[0006] In one embodiment, the LLC converter circuit unit further includes a third resistor, a fourth resistor, and a second diode. The first end of the third resistor is electrically connected to the source of the second field-effect transistor, and the second end of the third resistor is electrically connected to the gate of the second field-effect transistor. The first end of the fourth resistor is electrically connected to the second end of the third resistor, and the second end of the fourth resistor is electrically connected to the controller. The second diode is connected in parallel with the fourth resistor.
[0007] In one embodiment, the LLC conversion circuit unit further includes a fifth resistor, the first end of which is electrically connected to the second end of the fourth resistor, the second end of which is electrically connected to the controller, and the gate of the second field-effect transistor is electrically connected to the controller through the fourth resistor and the fifth resistor.
[0008] In one embodiment, the LLC conversion circuit unit further includes a sixth resistor, the first end of which is electrically connected to the second end of the second resistor, the second end of which is electrically connected to the controller, and the gate of the first field-effect transistor is electrically connected to the controller through the second resistor and the sixth resistor.
[0009] In one embodiment, the LLC converter circuit unit further includes an inductor and a third capacitor. The first end of the inductor is electrically connected to the second end of the transformer, the second end of the inductor is electrically connected to the first end of the third capacitor, and the second end of the third capacitor is grounded.
[0010] In one embodiment, the LLC conversion circuit unit further includes a fourth capacitor, the first terminal of which is electrically connected to the first terminal of the third capacitor, and the second terminal of which is electrically connected to the controller.
[0011] In one embodiment, the LLC conversion circuit unit further includes a fifth capacitor, the first end of which is electrically connected to the second end of the fourth capacitor, and the second end of the fifth capacitor is electrically connected to the controller; the fourth capacitor is electrically connected to the controller through the fifth capacitor.
[0012] In one embodiment, the LLC converter circuit unit further includes a sixth capacitor and a seventh resistor. The first terminal of the sixth capacitor is electrically connected to the second terminal of the fourth capacitor, and the second terminal of the sixth capacitor is grounded. The seventh resistor is connected in parallel with the sixth capacitor.
[0013] In one embodiment, the LLC conversion circuit unit further includes a seventh capacitor and an eighth resistor. The first terminal of the seventh capacitor is electrically connected to the first terminal of the fourth capacitor, and the second terminal of the seventh capacitor is electrically connected to the first terminal of the eighth resistor and the controller. The second terminal of the eighth resistor is grounded.
[0014] In one embodiment, the LLC converter circuit unit further includes a ninth resistor, a tenth resistor, an eighth capacitor, and a ninth capacitor. The first end of the ninth resistor is electrically connected to the first end of the fourth capacitor, the second end of the ninth resistor is electrically connected to the first end of the tenth resistor, and the second end of the tenth resistor is electrically connected to the second end of the seventh capacitor. The eighth capacitor is connected in parallel with the eighth resistor and the ninth capacitor.
[0015] This invention has the following beneficial effects: Through the cooperation between the first resistor, the second resistor, the first capacitor, the second capacitor, the first diode, the first field-effect transistor, and the second field-effect transistor, this invention enables the circuit to discharge when the first field-effect transistor is off and the second field-effect transistor is on, thereby achieving zero-voltage turn-on, reducing switching losses, and improving the charging efficiency of the charging circuit. In other words, it can achieve zero-voltage turn-on and zero-current turn-off of the switching transistor, greatly reducing switching losses and improving conversion efficiency, enabling the adapter to maintain high-efficiency operation over a wide load range. In addition, it also has the advantages of simple circuit structure, low cost, and low power consumption. Attached Figure Description
[0016] Figure 1 This is a circuit diagram showing the coordination between the controller, transformer, and LLC converter circuit unit of the low-power power adapter circuit of this utility model. Detailed Implementation
[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, embodiments of the present invention and the various features thereof can be combined with each other, all of which are within the protection scope of the present invention.
[0018] Please see Figure 1 This utility model provides a low-power power adapter circuit, including a controller U, a transformer T, and an LLC converter circuit unit electrically connected to the transformer T. The circuit may also include an input rectifier and filter circuit unit, a PFC circuit unit, and an output rectifier and filter circuit unit. The PFC circuit unit is electrically connected to the input rectifier and filter circuit unit and the LLC converter circuit unit, and the output rectifier and filter circuit unit is electrically connected to the secondary coil of the transformer T to output electrical energy to the electrical device.
[0019] In this embodiment, the LLC converter circuit unit includes a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2, a first diode D1, a first field-effect transistor Q1, and a second field-effect transistor Q2. The first terminal of the first resistor R1 is electrically connected to the source of the first field-effect transistor Q1, and the second terminal of the first resistor R1 is electrically connected to the gate of the first field-effect transistor Q1. The first terminal of the second resistor R2 is electrically connected to the second terminal of the first resistor R1, and the second terminal of the second resistor R2 is electrically connected to the controller U.
[0020] The first terminal of the first capacitor C1 is electrically connected to the source of the first field-effect transistor Q1, and the second terminal of the first capacitor C1 is electrically connected to the drain of the first field-effect transistor Q1. The first terminal of the second capacitor C2 is electrically connected to the source of the second field-effect transistor Q2, and the second terminal of the second capacitor C2 is electrically connected to the drain of the second field-effect transistor Q2. The first diode D1 is connected in parallel with the second resistor R2, and the anode of the first diode D1 is electrically connected to the gate of the first field-effect transistor Q1, and the cathode of the first diode D1 is electrically connected to the second terminal of the second resistor R2.
[0021] Since the first diode D1 is connected in parallel with the second resistor R2, the voltage across the second resistor R2 changes with the current, thus stabilizing the voltage across the diode and improving signal transmission stability. Preferably, the second resistor R2 has an appropriate temperature coefficient, which can offset some of the voltage changes in the first diode D1 caused by temperature variations, thereby making the output of the entire circuit more stable.
[0022] In this configuration, there are two diodes, D1, arranged in parallel. The forward voltage drop of a diode may fluctuate due to changes in current. By connecting multiple diodes in parallel, this fluctuation can be reduced, thereby improving voltage stability.
[0023] The source of the first field-effect transistor Q1 is electrically connected to the first terminal of the transformer T, that is, the source of the first field-effect transistor Q1 is electrically connected to one end of the primary coil of the transformer T. The drain of the first field-effect transistor Q1 is electrically connected to the PFC circuit unit through the fuse F. The source of the second field-effect transistor Q2 is grounded, the drain of the second field-effect transistor Q2 is electrically connected to the source of the first field-effect transistor Q1, and the gate of the second field-effect transistor Q2 is electrically connected to the controller U.
[0024] The LLC converter circuit unit also includes a third resistor R3, a fourth resistor R4, and a second diode D2. The first terminal of the third resistor R3 is electrically connected to the source of the second field-effect transistor Q2, and the second terminal of the third resistor R3 is electrically connected to the gate of the second field-effect transistor Q2. The first terminal of the fourth resistor R4 is electrically connected to the second terminal of the third resistor R3, and the second terminal of the fourth resistor R4 is electrically connected to the controller U. The second diode D2 is connected in parallel with the fourth resistor R4.
[0025] The LLC converter circuit unit also includes a fifth resistor R5 and a sixth resistor R6. The first terminal of the fifth resistor R5 is electrically connected to the second terminal of the fourth resistor R4, and the second terminal of the fifth resistor R5 is electrically connected to the controller U. The gate of the second field-effect transistor Q2 is electrically connected to the controller U through the fourth resistor R4 and the fifth resistor R5. The first terminal of the sixth resistor R6 is electrically connected to the second terminal of the second resistor R2, and the second terminal of the sixth resistor R6 is electrically connected to the controller U. The gate of the first field-effect transistor Q1 is electrically connected to the controller U through the second resistor R2 and the sixth resistor R6. Current limiting is achieved through the fifth resistor R5 and the sixth resistor R6.
[0026] The LLC converter circuit unit also includes an inductor L, a third capacitor C3, and a fourth capacitor C4. The first terminal of inductor L is electrically connected to the second terminal of transformer T, meaning the first terminal of inductor L is electrically connected to the other end of the primary coil of transformer T. This inductor L smooths current changes, making the circuit's dynamic response more stable. The second terminal of inductor L is electrically connected to the first terminal of the third capacitor C3, and the second terminal of the third capacitor C3 is grounded. The first terminal of the fourth capacitor C4 is electrically connected to the first terminal of the third capacitor C3, and the second terminal of the fourth capacitor C4 is electrically connected to the controller U. Because transformer T and the inductor L used for resonance are designed independently, smaller inductors and transformers with higher power outputs can be selected more flexibly, significantly reducing product size and achieving better performance.
[0027] The LLC conversion circuit unit also includes a fifth capacitor C5, the first terminal of which is electrically connected to the second terminal of the fourth capacitor C4, and the second terminal of the fifth capacitor C5 is electrically connected to the controller U. The fourth capacitor C4 is electrically connected to the controller U through the fifth capacitor C5.
[0028] The LLC converter circuit unit also includes a sixth capacitor C6 and a seventh resistor R7. The first terminal of the sixth capacitor C6 is electrically connected to the second terminal of the fourth capacitor C4, and the second terminal of the sixth capacitor C6 is grounded. The seventh resistor R7 is connected in parallel with the sixth capacitor C6.
[0029] The LLC conversion circuit unit also includes a seventh capacitor C7 and an eighth resistor R8. The first end of the seventh capacitor C7 is electrically connected to the first end of the fourth capacitor C4, and the second end of the seventh capacitor C7 is electrically connected to the first end of the eighth resistor R8 and the controller U. The second end of the eighth resistor R8 is grounded.
[0030] The LLC converter circuit unit also includes a ninth resistor R9, a tenth resistor R10, an eighth capacitor C8, and a ninth capacitor C9. The first terminal of the ninth resistor R9 is electrically connected to the first terminal of the fourth capacitor C4, and the second terminal of the ninth resistor R9 is electrically connected to the first terminal of the tenth resistor R10. The second terminal of the tenth resistor R10 is electrically connected to the second terminal of the seventh capacitor C7. The eighth capacitor C8 is connected in parallel with the eighth resistor R8 and the ninth capacitor C9. The parallel connection of capacitors and resistors forms a low-pass filter. Capacitors have lower impedance to high-frequency signals, while resistors have a fixed impedance to signals of all frequencies. High-frequency signals preferentially pass through the capacitor, while low-frequency signals pass through the resistor, thus filtering out high-frequency noise. In addition, the circuit also includes a tenth capacitor C10, an eleventh capacitor C11, an eleventh resistor R11, and a twelfth resistor R12, with their connections as follows: Figure 1 As shown.
[0031] In summary, this invention, through the cooperation of the first resistor R1, the second resistor R2, the first capacitor C1, the second capacitor C2, the first diode D1, the first field-effect transistor Q1, and the second field-effect transistor Q2, enables the circuit to discharge when the first field-effect transistor Q1 is off and the second field-effect transistor Q2 is on, thereby achieving zero-voltage turn-on, reducing switching losses, and improving the charging efficiency of the charging circuit. In other words, it can achieve zero-voltage turn-on and zero-current turn-off of the switching transistors, greatly reducing switching losses and improving conversion efficiency, enabling the adapter to maintain high-efficiency operation over a wide load range. In addition, it also has the advantages of simple circuit structure, low cost, and low power consumption.
[0032] The low-power power adapter circuit provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of this utility model. Furthermore, those skilled in the art will recognize that, based on the idea of this utility model, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification is only an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model and should not be construed as a limitation of this utility model.
Claims
1. A low-power power adapter circuit, characterized in that, The system includes a controller, a transformer, and an LLC converter circuit unit electrically connected to the transformer. The LLC converter circuit unit includes a first resistor, a second resistor, a first capacitor, a second capacitor, a first diode, a first field-effect transistor (FET), and a second FET. A first terminal of the first resistor is electrically connected to the source of the first FET, and a second terminal of the first resistor is electrically connected to the gate of the first FET. A first terminal of the second resistor is electrically connected to the second terminal of the first resistor, and a second terminal of the second resistor is electrically connected to the controller. The first terminal of the first capacitor is electrically connected to the source of the first field-effect transistor (FET), and the second terminal of the first capacitor is electrically connected to the drain of the first FET. The first terminal of the second capacitor is electrically connected to the source of the second FET, and the second terminal of the second capacitor is electrically connected to the drain of the second FET. The first diode is connected in parallel with the second resistor. The source of the first FET is electrically connected to the first terminal of the transformer. The source of the second FET is grounded, the drain of the second FET is electrically connected to the source of the first FET, and the gate of the second FET is electrically connected to the controller.
2. The low-power power adapter circuit as described in claim 1, characterized in that, The LLC converter circuit unit further includes a third resistor, a fourth resistor, and a second diode. The first end of the third resistor is electrically connected to the source of the second field-effect transistor, and the second end of the third resistor is electrically connected to the gate of the second field-effect transistor. The first end of the fourth resistor is electrically connected to the second end of the third resistor, and the second end of the fourth resistor is electrically connected to the controller. The second diode is connected in parallel with the fourth resistor.
3. The low-power power adapter circuit as described in claim 2, characterized in that, The LLC conversion circuit unit further includes a fifth resistor, the first end of which is electrically connected to the second end of the fourth resistor, and the second end of the fifth resistor is electrically connected to the controller. The gate of the second field-effect transistor is electrically connected to the controller through the fourth resistor and the fifth resistor.
4. The low-power power adapter circuit as described in claim 1 or 2, characterized in that, The LLC conversion circuit unit further includes a sixth resistor, the first end of which is electrically connected to the second end of the second resistor, and the second end of which is electrically connected to the controller. The gate of the first field-effect transistor is electrically connected to the controller through the second resistor and the sixth resistor.
5. The low-power power adapter circuit as described in claim 1 or 2, characterized in that, The LLC converter circuit unit further includes an inductor and a third capacitor. The first end of the inductor is electrically connected to the second end of the transformer, the second end of the inductor is electrically connected to the first end of the third capacitor, and the second end of the third capacitor is grounded.
6. The low-power power adapter circuit as described in claim 5, characterized in that, The LLC conversion circuit unit further includes a fourth capacitor, the first end of which is electrically connected to the first end of the third capacitor, and the second end of which is electrically connected to the controller.
7. The low-power power adapter circuit as described in claim 6, characterized in that, The LLC conversion circuit unit further includes a fifth capacitor, the first end of which is electrically connected to the second end of the fourth capacitor, and the second end of the fifth capacitor is electrically connected to the controller; the fourth capacitor is electrically connected to the controller through the fifth capacitor.
8. The low-power power adapter circuit as described in claim 6, characterized in that, The LLC converter circuit unit further includes a sixth capacitor and a seventh resistor. The first terminal of the sixth capacitor is electrically connected to the second terminal of the fourth capacitor, and the second terminal of the sixth capacitor is grounded. The seventh resistor is connected in parallel with the sixth capacitor.
9. The low-power power adapter circuit as described in claim 6, characterized in that, The LLC conversion circuit unit further includes a seventh capacitor and an eighth resistor. The first terminal of the seventh capacitor is electrically connected to the first terminal of the fourth capacitor, and the second terminal of the seventh capacitor is electrically connected to the first terminal of the eighth resistor and the controller. The second terminal of the eighth resistor is grounded.
10. The low-power power adapter circuit as described in claim 9, characterized in that, The LLC converter circuit unit further includes a ninth resistor, a tenth resistor, an eighth capacitor, and a ninth capacitor. The first end of the ninth resistor is electrically connected to the first end of the fourth capacitor, the second end of the ninth resistor is electrically connected to the first end of the tenth resistor, and the second end of the tenth resistor is electrically connected to the second end of the seventh capacitor. The eighth capacitor is connected in parallel with the eighth resistor and the ninth capacitor.