A power adapter circuit with high reliability
By introducing an LLC converter circuit unit and a transistor-driven MOSFET design into the power adapter, the problem of excessively high power device temperature was solved, and the reliability of the power adapter was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SICHUAN XINGUANCHENG ELECTRONIC TECH CO LTD
- Filing Date
- 2025-07-03
- Publication Date
- 2026-07-21
Smart Images
Figure CN224538044U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power adapter technology, and in particular to a highly reliable power adapter circuit. Background Technology
[0002] With the development of technology, electronic products have flourished and permeated all aspects of life. In electronic products, power adapters convert AC mains voltage to power the devices, enabling them to obtain the necessary electrical energy. Power adapters play a crucial role in supplying voltage and current to electronic products. When connected to terminal devices, power adapters often experience overload or heavy load conditions due to peak voltage and current exceeding their rated load. This causes the power devices' temperature to rise rapidly, potentially leading to severe impact damage and melting of plastic parts. Current products can only mitigate this damage through the performance of the power devices themselves, but cannot completely solve the problem. Utility Model Content
[0003] The technical problem solved by this utility model is to provide a highly reliable power adapter circuit that can avoid overheating of power devices.
[0004] This utility model provides a highly reliable power adapter circuit, including a controller, a transformer, and an LLC conversion circuit unit. The LLC conversion circuit unit includes a first resistor, an inductor, a first capacitor, a first diode, a first transistor, a second transistor, a first field-effect transistor, and a second field-effect transistor. The first end of the first resistor is electrically connected to the emitter of the first transistor, and the second end of the first resistor is electrically connected to the gate of the first field-effect transistor. The first end of the inductor is electrically connected to the collector of the first transistor, and the second end of the inductor is electrically connected to the first end of the primary coil of the transformer.
[0005] The first terminal of the first capacitor is electrically connected to the second terminal of the primary coil of the transformer, and the second terminal of the first capacitor is grounded; the anode of the first diode is electrically connected to the base of the first transistor and the controller, and the cathode of the first diode is electrically connected to the emitter of the first transistor; the base of the second transistor is electrically connected to the controller, the emitter of the second transistor is electrically connected to the gate of the second field-effect transistor, and the collector of the second transistor is electrically connected to the source of the second field-effect transistor and grounded; the source of the first field-effect transistor and the drain of the second field-effect transistor are electrically connected to the first terminal of the inductor.
[0006] In one embodiment, the LLC conversion circuit unit further includes a second diode, the anode of the second diode being electrically connected to the base of the second transistor and the controller, and the cathode of the second diode being electrically connected to the emitter of the second transistor.
[0007] In one embodiment, the LLC converter circuit unit further includes a second resistor, the first end of which is electrically connected to the emitter of the second transistor, the second end of which is electrically connected to the base of the second field-effect transistor, and the emitter of the second transistor is electrically connected to the base of the second field-effect transistor through the second resistor.
[0008] In one embodiment, the LLC converter circuit unit further includes a third resistor and a fourth resistor. The first end of the third resistor is electrically connected to the source of the first field-effect transistor, and the second end of the third resistor is electrically connected to the gate of the first field-effect transistor. The first end of the fourth resistor is electrically connected to the source of the second field-effect transistor, and the second end of the fourth resistor is electrically connected to the gate of the second field-effect transistor.
[0009] In one embodiment, the LLC conversion circuit unit further includes a fifth resistor and a sixth resistor, wherein the base of the first transistor is electrically connected to the controller through the fifth resistor; and the base of the second transistor is electrically connected to the controller through the sixth resistor.
[0010] In one embodiment, the LLC converter circuit unit further includes a second capacitor, the first end of which is electrically connected to the drain of the first field-effect transistor, and the second end of which is electrically connected to the second end of the primary coil of the transformer.
[0011] In one embodiment, the LLC conversion circuit unit further includes a third capacitor, the first terminal of which is electrically connected to the first terminal of the second capacitor, and the second terminal of the third capacitor is grounded.
[0012] In one embodiment, the LLC converter circuit unit further includes a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh resistor. The first terminal of the fourth capacitor is electrically connected to the first terminal of the first capacitor, the second terminal of the fourth capacitor is electrically connected to the first terminal of the fifth capacitor, and the second terminal of the fifth capacitor is electrically connected to the controller. 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 offers the following advantages: By using a first transistor and a second transistor to drive a first field-effect transistor (FET) and a second FET respectively, the transistor's strong voltage and current amplification capabilities allow it to amplify small signals into large signals and provide sufficient current to drive the FET. This enhances the FET's driving capability and improves its operational stability and reliability. Furthermore, the transistor effectively controls the FET's leakage current and quiescent current, preventing overheating and damage due to excessive leakage current, thus avoiding excessively high temperatures in the power devices. Additionally, the parallel connection of a first diode between the base and emitter of the first transistor reduces the reverse saturation current between them, thereby decreasing power consumption and heat generation in the circuit. 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 highly reliable 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 highly reliable power adapter circuit, including a controller U, a transformer TP, and an LLC converter circuit unit electrically connected to the transformer TP. 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 TP to output electrical energy to the electrical equipment.
[0019] In this embodiment, the LLC converter circuit unit includes a first resistor R1, an inductor L, a first capacitor C1, a first diode D1, a first transistor T1, a second transistor T2, 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 emitter of the first transistor T1, 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 inductor L is electrically connected to the collector of the first transistor T1, and the second terminal of the inductor L is electrically connected to the first terminal of the primary coil of the transformer TP. Together with the other capacitors, they form a resonant cavity. Because the transformer TP and the inductor L used for resonance are designed independently, smaller inductors and transformers that can achieve higher power are more flexibly selected, significantly reducing the product size and achieving better performance.
[0020] The first terminal of the first capacitor C1 is electrically connected to the second terminal of the primary coil of the transformer TP, and the second terminal of the first capacitor C1 is grounded. The anode of the first diode D1 is electrically connected to the base of the first transistor T1 and the controller U, and the cathode of the first diode D1 is electrically connected to the emitter of the first transistor T1. The base of the second transistor T2 is electrically connected to the controller U, the emitter of the second transistor T2 is electrically connected to the gate of the second field-effect transistor Q2, and the collector of the second transistor T2 is electrically connected to the source of the second field-effect transistor Q2 and grounded. The source of the first field-effect transistor Q1 and the drain of the second field-effect transistor Q2 are electrically connected to the first terminal of the inductor L.
[0021] The LLC converter circuit unit also includes a second diode D2. The anode of the second diode D2 is electrically connected to the base of the second transistor T2 and the controller U, and the cathode of the second diode D2 is electrically connected to the emitter of the second transistor T2. The second diode D2 is connected in parallel with the base and emitter of the second transistor T2, which reduces the reverse saturation current between the base and emitter of the second transistor T2, thereby reducing the circuit's power consumption and heat generation.
[0022] The LLC converter circuit unit also includes a second resistor R2. The first end of the second resistor R2 is electrically connected to the emitter of the second transistor T2, and the second end is electrically connected to the base of the second field-effect transistor Q2. The emitter of the second transistor T2 is electrically connected to the base of the second field-effect transistor Q2 through the second resistor R2. The second resistor R2 can isolate the electrical characteristics between the second transistor T2 and the second field-effect transistor Q2 to a certain extent. Since the gate input impedance of the second field-effect transistor Q2 is very high, while the output impedance of the second transistor T2 is relatively low, the second resistor R2 can prevent the low impedance characteristic of the second transistor T2 from directly affecting the high impedance characteristic of the second field-effect transistor Q2, thereby achieving better electrical matching between the two.
[0023] The LLC converter circuit unit also includes a third resistor R3 and a fourth resistor R4. The first terminal of the third resistor R3 is electrically connected to the source of the first field-effect transistor Q1, and the second terminal of the third resistor R3 is electrically connected to the gate of the first field-effect transistor Q1. The first terminal of the fourth resistor R4 is electrically connected to the source of the second field-effect transistor Q2, and the second terminal of the fourth resistor R4 is electrically connected to the gate of the second field-effect transistor Q2.
[0024] The LLC converter circuit unit also includes a fifth resistor R5 and a sixth resistor R6. The base of the first transistor T1 is electrically connected to the controller U through the fifth resistor R5. The base of the second transistor T2 is electrically connected to the controller U through the sixth resistor R6. Since the base of a transistor typically allows very little current to pass through it, directly connecting the output of the microcontroller (which acts as the controller U) to the base of the transistor could result in excessive base current, potentially damaging the transistor. The fifth resistor R5 and the sixth resistor R6, acting as base resistors, limit the current flowing through the base, ensuring it remains within the transistor's safe operating range.
[0025] The LLC converter circuit unit also includes a second capacitor C2 and a third capacitor C3. The first terminal of the second capacitor C2 is electrically connected to the drain of the first field-effect transistor Q1, and the second terminal of the second capacitor C2 is electrically connected to the second terminal of the primary coil of the transformer TP. The first terminal of the third capacitor C3 is electrically connected to the first terminal of the second capacitor C2, and the second terminal of the third capacitor C3 is grounded.
[0026] The LLC converter circuit unit also includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh resistor R7. The first terminal of the fourth capacitor C4 is electrically connected to the first terminal of the first capacitor C1, and the second terminal of the fourth capacitor C4 is electrically connected to the first terminal of the fifth capacitor C5. The second terminal of the fifth capacitor C5 is electrically connected to the controller U. 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.
[0027] The LLC conversion circuit unit also includes a seventh capacitor C7 and an eighth resistor R8. The first terminal of the seventh capacitor C7 is electrically connected to the first terminal of the fourth capacitor C4, and the second terminal of the seventh capacitor C7 is electrically connected to the first terminal of the eighth resistor R8 and the controller U. The second terminal of the eighth resistor R8 is grounded.
[0028] 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.
[0029] In summary, this invention uses a first transistor T1 and a second transistor T2 to drive a first field-effect transistor Q1 and a second field-effect transistor Q2, respectively. Since transistors have strong voltage and current amplification capabilities, they can amplify small signals into large signals and provide sufficient current to drive the field-effect transistors, thus enhancing the driving capability of the field-effect transistors and improving their operational stability and reliability. Furthermore, the transistors can effectively control the leakage current and quiescent current of the field-effect transistors, preventing overheating and damage due to excessive leakage current, thereby avoiding excessively high temperatures in the power devices. In addition, the first diode D1 is connected in parallel between the base and emitter of the first transistor T1, which reduces the reverse saturation current between the base and emitter of the first transistor T1, thereby reducing power consumption and heat generation in the circuit.
[0030] The highly reliable 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 highly reliable power adapter circuit, characterized in that, The system includes a controller, a transformer, and an LLC converter circuit unit. The LLC converter circuit unit includes a first resistor, an inductor, a first capacitor, a first diode, a first transistor, a second transistor, a first field-effect transistor, and a second field-effect transistor. The first terminal of the first resistor is electrically connected to the emitter of the first transistor, and the second terminal of the first resistor is electrically connected to the gate of the first field-effect transistor. The first terminal of the inductor is electrically connected to the collector of the first transistor, and the second terminal of the inductor is electrically connected to the first terminal of the primary coil of the transformer. The first terminal of the first capacitor is electrically connected to the second terminal of the primary coil of the transformer, and the second terminal of the first capacitor is grounded; the anode of the first diode is electrically connected to the base of the first transistor and the controller, and the cathode of the first diode is electrically connected to the emitter of the first transistor; the base of the second transistor is electrically connected to the controller, the emitter of the second transistor is electrically connected to the gate of the second field-effect transistor, and the collector of the second transistor is electrically connected to the source of the second field-effect transistor and grounded; the source of the first field-effect transistor and the drain of the second field-effect transistor are electrically connected to the first terminal of the inductor.
2. The high-reliability power adapter circuit as described in claim 1, characterized in that, The LLC conversion circuit unit further includes a second diode, the anode of which is electrically connected to the base of the second transistor and the controller, and the cathode of which is electrically connected to the emitter of the second transistor.
3. The high-reliability power adapter circuit as described in claim 1 or 2, characterized in that, The LLC conversion circuit unit further includes a second resistor, the first end of which is electrically connected to the emitter of the second transistor, the second end of which is electrically connected to the base of the second field-effect transistor, and the emitter of the second transistor is electrically connected to the base of the second field-effect transistor through the second resistor.
4. The high-reliability power adapter circuit as described in claim 1 or 2, characterized in that, The LLC conversion circuit unit further includes a third resistor and a fourth resistor. The first end of the third resistor is electrically connected to the source of the first field-effect transistor, and the second end of the third resistor is electrically connected to the gate of the first field-effect transistor. The first end of the fourth resistor is electrically connected to the source of the second field-effect transistor, and the second end of the fourth resistor is electrically connected to the gate of the second field-effect transistor.
5. The high-reliability power adapter circuit as described in claim 1 or 2, characterized in that, The LLC conversion circuit unit further includes a fifth resistor and a sixth resistor. The base of the first transistor is electrically connected to the controller through the fifth resistor; the base of the second transistor is electrically connected to the controller through the sixth resistor.
6. The high-reliability power adapter circuit as described in claim 1 or 2, characterized in that, The LLC converter circuit unit further includes a second capacitor, the first end of which is electrically connected to the drain of the first field-effect transistor, and the second end of which is electrically connected to the second end of the primary coil of the transformer.
7. The high-reliability power adapter circuit as described in claim 6, characterized in that, The LLC conversion circuit unit further includes a third capacitor, the first terminal of which is electrically connected to the first terminal of the second capacitor, and the second terminal of the third capacitor is grounded.
8. The high-reliability power adapter circuit as described in claim 1 or 2, characterized in that, The LLC converter circuit unit further includes a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh resistor. The first terminal of the fourth capacitor is electrically connected to the first terminal of the first capacitor, the second terminal of the fourth capacitor is electrically connected to the first terminal of the fifth capacitor, and the second terminal of the fifth capacitor is electrically connected to the controller. 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 high-reliability power adapter circuit as described in claim 8, 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 high-reliability 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.