A dc-ac inverter for a lithium battery pack

Abstract

The utility model provides a kind of DC-AC inverter of lithium battery pack, it is related to inverter technical field, including inverter power supply circuit, its logic control input end connects main control chip, power input end connects lithium battery pack, switch starting end connects the inverter starting end of main control chip;USB power supply circuit, its power input end connects lithium battery pack, switch starting end connects the USB starting end of main control chip;LED lighting circuit, its power input end connects lithium battery pack, and lighting starting end connects the LED starting end of main control chip.Affirmative effect is that the inverter and lithium battery pack adopt separable design, and the same specification battery can be quickly replaced when power is depleted, guaranteeing power supply continuity, breaking through the limitations of traditional integrated type;And integrated AC inverter, DC / USB output and LED lighting function, provide integrated power supply scheme, users do not need to carry additional multiple equipment, significantly improve portability and use convenience, meet diversified power demand.

Description

Technical Field

[0001] This novel experimental invention relates to the field of inverter technology, and in particular to a DC-AC inverter with a lithium battery pack. Background Technology

[0002] Currently, commercially available lithium battery packs, especially the 18.5V series, have achieved a high level of maturity and widespread adoption. However, their functionality is relatively limited, typically providing only DC output and failing to directly meet users' AC power needs. Although independent DC-AC inverter products exist, most of these devices employ a closed structure integrated with the lithium battery, preventing users from replacing the battery pack themselves. This severely restricts the continuity and flexibility of mobile use.

[0003] Furthermore, these integrated inverters typically lack common DC power supply functions such as USB output, requiring users to carry multiple conversion devices or power modules, increasing complexity and reducing portability. Additionally, existing product lines lack power solutions that support user-replaceable batteries while integrating AC inversion and multiple DC output functions, failing to fully meet the comprehensive needs for power continuity, multifunctionality, and maintainability in scenarios such as outdoor operations, emergency power supply, or mobile offices. Utility Model Content

[0004] To address the problems existing in the prior art, this experiment provides a novel DC-AC inverter with a lithium battery pack, comprising: An inverter power supply circuit, wherein the logic control input terminal of the inverter power supply circuit is connected to the logic control output terminal of the main control chip, the power input terminal of the inverter power supply circuit is connected to the power supply terminal of the lithium battery pack, and the switch start terminal of the inverter power supply circuit is connected to the inverter start terminal of the main control chip; USB power supply circuit, wherein the power input terminal of the USB power supply circuit is connected to the power supply terminal of the lithium battery pack, and the switch start terminal of the USB power supply circuit is connected to the USB start terminal of the main control chip; The LED lighting circuit has its power input terminal connected to the power supply terminal of the lithium battery pack, and its lighting start terminal connected to the LED start terminal of the main control chip.

[0005] Preferably, the inverter power supply circuit includes a switching power supply circuit and a full-bridge inverter circuit; the logic control output terminal of the main control chip includes a switching control output terminal and an inverter control output terminal; The switching control receiving terminal of the switching power supply circuit is connected to the switching control output terminal of the main control chip, and the inverter control receiving terminal of the full-bridge inverter circuit is connected to the inverter control output terminal. The power output terminal of the switching power supply circuit is connected to the power input terminal of the full-bridge inverter circuit, and the power input terminal of the switching power supply circuit is connected to the lithium battery pack.

[0006] Preferably, the switching power supply circuit includes: A driver chip, wherein the second pin of the driver chip is connected to the sixth pin of the main control chip, and the fourth pin of the driver chip is connected to the ninth pin of the main control chip; The first MOSFET, the gate of which is connected to the fifth pin of the driver chip via a first resistor; The second MOSFET has its gate connected to the seventh pin of the driver chip via a second resistor, its source connected to the source of the first MOSFET, and a third resistor and a first capacitor connected in series between the drain of the second MOSFET and the drain of the first MOSFET. A transformer, wherein the first connection terminal of the transformer is connected to the drain of the first MOSFET, the fifth connection terminal of the transformer is connected to the drain of the second MOSFET, the tenth connection terminal of the transformer is connected to the cathode of the first diode and the anode of the second diode, the ninth connection terminal of the transformer is connected to the cathode of the third diode and the anode of the fourth diode, the anode of the third diode is connected to the anode of the first diode, and the cathode of the second diode is connected to the cathode of the fourth diode. A fourth resistor and a second capacitor are connected in parallel between the anode of the first diode and the cathode of the fourth diode; The third MOSFET has its source connected to the second, third, and fourth terminals of the transformer. A fifth resistor is connected in series between the gate and drain of the third MOSFET. The drain of the third MOSFET is connected to the lithium battery pack and to the power supply through a sixth resistor. The anode of the first diode is connected to the power input terminal of the full-bridge inverter circuit.

[0007] Preferably, the inverter power supply circuit further includes a power supply self-locking circuit, which includes: The first transistor has its collector connected to the gate of the third MOS transistor via a seventh resistor. An eighth resistor is connected in series between the emitter and base of the first transistor. The base of the first transistor is connected to the power enable pin of the main control chip via a ninth resistor.

[0008] Preferably, the full-bridge inverter circuit includes: A first optocoupler, wherein the first pin and the second pin of the first optocoupler are respectively connected to the twelfth pin of the main control chip through the tenth resistor and the eleventh resistor; The second optocoupler has its first and second pins connected to the thirteenth pin of the main control chip via the twelfth and thirteenth resistors, respectively. The base of the second transistor is connected to the third pin of the first optocoupler through the fourteenth resistor, and the emitter and base of the second transistor are connected in series with the fifteenth resistor. The base of the third transistor is connected to the third pin of the second optocoupler through the sixteenth resistor, and the emitter and base of the third transistor are connected in series with the seventeenth resistor. A current inverter bridge is provided, wherein the first terminal of the current inverter bridge is connected to the collector of the second transistor through the eighteenth resistor, the midpoint of the first bridge arm of the current inverter bridge is connected to one end of the third capacitor and the cathode of the fifth diode, the anode of the fifth diode is connected to the first terminal of the current inverter bridge, the other end of the third capacitor is connected to one end of the nineteenth resistor and the anode of the sixth diode, the other end of the nineteenth resistor is connected to the collector of the second transistor, and the cathode of the sixth diode is connected to the inverter power supply. The second terminal of the current inverter bridge is connected to one end of the twentieth resistor and the cathode of the seventh diode, and the other end of the twentieth resistor and the anode of the seventh diode are connected to the third terminal of the first optocoupler. The third terminal of the current inverter bridge is connected to the collector of the third transistor through the twenty-first resistor. The midpoint of the second arm of the current inverter bridge is connected to one end of the fourth capacitor and the cathode of the eighth diode. The anode of the eighth diode is connected to the third terminal of the current inverter bridge. The other end of the fourth capacitor is connected to one end of the twenty-second resistor and the anode of the eighth diode. The other end of the twenty-second resistor is connected to the collector of the third transistor. The cathode of the eighth diode is connected to the inverter power supply. The fourth terminal of the current inverter bridge is connected to one end of the twenty-third resistor and the cathode of the ninth diode, and the other end of the twenty-third resistor and the anode of the ninth diode are connected to the third terminal of the second optocoupler. The current input terminal of the current inverter bridge is connected to the current output terminal of the power switch circuit. The midpoint of the first bridge arm and the midpoint of the second bridge arm of the current inverter serve as the external output terminals of the inverter power supply circuit.

[0009] Preferably, the current inverter bridge includes: The fourth MOS transistor, the gate of which is connected to the collector of the second transistor through the eighteenth resistor; The fifth MOS transistor, the gate of which is connected to one end of the twentieth resistor; The sixth MOS transistor, the gate of which is connected to the collector of the third transistor through the twenty-first resistor; The seventh MOS transistor, the gate of which is connected to one end of the twenty-third resistor; The drain of the fourth MOS transistor and the drain of the sixth MOS transistor are connected to the current output terminal of the power switch circuit. The connection point between the source of the fourth MOS transistor and the drain of the fifth MOS transistor serves as the midpoint of the first arm of the current inverter bridge, and the connection point between the source of the sixth MOS transistor and the drain of the seventh MOS transistor serves as the midpoint of the second arm of the current inverter bridge.

[0010] Preferably, the inverter power supply circuit further includes an overcurrent detection circuit, comprising: The 24th resistor has one end connected to the source of the first MOSFET, and the other end connected to one end of the 25th resistor and one end of the 26th resistor. The other end of the 25th resistor is connected to the overcurrent power supply. An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to one end of the 26th resistor and one end of the 6th capacitor, the other end of the 6th capacitor is grounded, the inverting input terminal of the operational amplifier is connected to one end of the 27th resistor, one end of the 28th resistor and the other end of the 7th capacitor, and the output terminal of the operational amplifier is connected to the other end of the 28th resistor, the other end of the 7th capacitor, one end of the 29th resistor and one end of the 30th resistor, the other end of the 27th resistor is grounded, and the other end of the 30th resistor is grounded; The other end of the 29th resistor is connected to the overcurrent detection pin of the main control chip.

[0011] Preferably, the USB power supply circuit includes: The USB driver chip has its first pin connected to one end of the thirtieth resistor, one end of the thirty-first resistor, and one end of the eighth capacitor. The other end of the thirty-first resistor is connected to one end of the ninth capacitor and one end of the tenth capacitor. The fifth pin of the USB driver chip is connected to the other end of the eighth capacitor, the other end of the thirtieth resistor, the other end of the ninth capacitor, and the other end of the tenth capacitor. The Type-C interface has its 12th, 13th, 14th, 15th and 16th pins connected, and also connected to the 5th pin of the USB driver chip, one end of the 11th capacitor, one end of the 12th capacitor, the cathode of the first transient voltage suppression diode, the cathode of the second transient voltage suppression diode and the 1st pin of the Type-C interface; The other end of the eleventh capacitor is connected to the anode of the first transient voltage suppression diode and the fourth pin of the Type-C interface. The other end of the eleventh capacitor is also connected to the first pin of the Type-C interface through the thirty-second resistor. The other end of the twelfth capacitor is connected to the anode of the second transient voltage suppression diode and the tenth pin of the Type-C interface. The other end of the twelfth capacitor is also connected to the first pin of the Type-C interface through the thirty-third resistor. The second and eleventh pins of the Type-C interface are connected to the third pin of the USB driver chip, and also to one end of the thirty-fourth resistor. The other end of the thirty-fourth resistor is connected to the eighth pin of the USB driver chip. The USB interface has a thirteenth capacitor connected in series between its first and fourth pins. The first pin of the USB interface is also connected to the fourth pin of the USB driver chip and one end of the thirty-fifth resistor. The other end of the thirty-fifth resistor is connected to the second pin of the USB driver chip. The sixth pin of the USB driver chip is connected to the first pin of the common mode inductor and one end of the thirteenth, fourteenth, and fifteenth capacitors; the fifth pin of the USB driver chip is connected to the second pin of the common mode inductor and the other end of the thirteenth, fourteenth, and fifteenth capacitors. A sixteenth capacitor is connected in series between the third and fourth pins of the common-mode inductor. The third pin of the common-mode inductor is connected to the source of the eighth MOS transistor. The fourth pin of the common-mode inductor is connected to the USB overcurrent detection circuit. The detection output of the USB overcurrent detection circuit is connected to the sixteenth pin of the main control chip. A 36th resistor is connected in series between the gate and drain of the eighth MOS transistor. The drain of the eighth MOS transistor is connected to the source of the third MOS transistor. The gate of the eighth MOS transistor is connected to one end of a 37th resistor. The other end of the 37th resistor is connected to the collector of the fourth transistor. A 38th resistor is connected in series between the emitter and base of the fourth transistor and grounded. The base of the fourth transistor is also connected to the 15th pin of the main control chip through a 39th resistor.

[0012] Preferably, it also includes a main control chip startup circuit, including: A start button is provided. The first end of the start button is connected to the power supply terminal of the lithium battery pack. The other end of the start button is connected to the cathode of the tenth diode and one end of the fortieth resistor. The other end of the fortieth resistor is connected to one end of the forty-first resistor, one end of the seventeenth capacitor, and the fifth pin of the main control chip. The other end of the forty-first resistor and the other end of the seventeenth capacitor are grounded. The startup chip has its second pin connected to the anode of the eleventh diode via a forty-second resistor. The second pin is also connected to the first pin of the startup chip and grounded via a seventeenth capacitor. The third pin is connected to one end of the eighteenth and nineteenth capacitors, with the other ends of the eighteenth and nineteenth capacitors grounded. The third pin is also connected to the twentieth pin of the main control chip, and further connected to the fourth pin of the main control chip via a forty-third resistor.

[0013] Preferably, the LED lighting circuit includes: An LED start button is provided, with one end connected to the power supply terminal of the lithium battery pack, and the other end connected to one end of the forty-fourth resistor and the cathode of the twelfth diode. The other end of the forty-fourth resistor is connected to one end of the forty-fifth resistor and one end of the twentieth capacitor. The other end of the forty-fifth resistor and the other end of the twentieth capacitor are grounded, and the other end of the forty-fourth resistor is also connected to the eleventh pin of the main control chip. The anode of the twelfth diode is also connected to the anode of the thirteenth diode and one end of the forty-second resistor, and the cathode of the thirteenth diode is connected to the power input terminal of the USB circuit. The first LED and the second LED have their cathodes connected to the LED power supply. The anodes of the first LED and the second LED are connected to the drain of the ninth MOS transistor through resistors forty-six and forty-seven, respectively. A resistor forty-eight is connected in series between the source and the gate of the ninth MOS transistor and grounded. The gate of the ninth MOS transistor is connected to the LED start-up terminal of the main control chip through resistor forty-nine.

[0014] The above technical solution has the following advantages or beneficial effects: The DC-AC inverter and lithium battery pack of this invention are two independent and separable components. When the battery is depleted, the user can easily remove it from the inverter and replace it with another fully charged battery pack of the same specifications, achieving continuous power supply and flexibility of use, breaking the limitation of the traditional integrated structure that cannot be replaced.

[0015] By integrating AC inverter, DC / USB output, and LED lighting into a single device, this product provides an all-in-one power solution. Users no longer need to carry multiple conversion devices, greatly improving portability and ease of use, and meeting diverse power needs. Attached Figure Description

[0016] Figure 1The circuit diagram of the switching power supply circuit is shown in a preferred embodiment of this novel experimental design. Figure 2 The circuit diagram of the full-bridge inverter circuit is shown in a preferred embodiment of this novel experimental design. Figure 3 The circuit diagram of the main control chip is shown in a preferred embodiment of this novel experimental design. Figure 4 The circuit diagram of the overcurrent detection circuit is shown in a preferred embodiment of this novel experimental design. Figure 5 The circuit diagram of the USB power supply circuit is shown in a preferred embodiment of this novel experimental design. Figure 6 The circuit diagram of the main control chip startup circuit is shown in a preferred embodiment of this novel experimental design. Figure 7 The circuit diagram of the LED lighting circuit is shown in a preferred embodiment of this novel experimental design. Figure 8 The circuit diagram of the transformer circuit is shown in a preferred embodiment of this novel experimental design. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this particular embodiment; other embodiments that conform to the spirit of the present invention may also fall within its scope.

[0018] In a preferred embodiment of this novel invention, based on the aforementioned problems existing in the prior art, a DC-AC inverter for a lithium battery pack is provided, comprising: The inverter power supply circuit has its logic control input terminal connected to the logic control output terminal of the main control chip, its power input terminal connected to the power supply terminal of the lithium battery pack, and its switch start terminal connected to the inverter start terminal of the main control chip. The USB power supply circuit has its power input terminal connected to the power supply terminal of the lithium battery pack, and its switch / start terminal connected to the USB start terminal of the main control chip. The LED lighting circuit has its power input terminal connected to the power supply terminal of the lithium battery pack, and its lighting start terminal connected to the LED start terminal of the main control chip.

[0019] Specifically, in this embodiment, the power input terminal of the inverter power supply circuit is directly connected to the power supply terminal of the lithium battery pack, enabling the mature lithium battery pack, which originally could only provide DC power, to be converted into AC power output through this inverter. This gives the standard battery pack a brand-new AC inverter function, solving the fundamental problem of the original product's single function.

[0020] In this embodiment, the power input terminals of all circuits (inverter, USB, LED) are connected to the lithium battery pack, rather than being fixedly integrated with the battery. This connection physically means that the inverter body and the lithium battery pack are two independent and separable components. When the battery is depleted, the user can easily remove it from the inverter and replace it with another fully charged battery pack of the same specifications, achieving continuous power supply and flexibility of use, breaking the limitation of the traditional integrated structure that cannot be replaced.

[0021] In this embodiment, in addition to the inverter circuit, a separate USB power supply circuit and an LED lighting circuit are also provided, and their power input terminals are also connected to the lithium battery pack. By integrating AC inverter, DC / USB output, and LED lighting functions into a single device, an integrated power solution is provided. Users no longer need to carry multiple conversion devices, greatly improving portability and ease of use, and meeting diverse power needs.

[0022] The inverter in this embodiment is based on the concept of a mature, high-volume lithium battery pack series on the market. All its circuit inputs are designed to be compatible with this universal battery pack. This greatly enriches the application scenarios and value of the original battery pack product line, provides consumers with more diversified choices, and reduces manufacturing and sales costs.

[0023] In summary, the core innovation of this embodiment lies in its detachable, modular, and multifunctional integrated design. It uses a single main control chip that integrates inverter, USB, and lighting control to uniformly manage all functional circuits, and powers all these circuits through a user-replaceable standard external lithium battery pack. This design cleverly balances functional richness with usage flexibility, directly addressing each of the shortcomings of existing products in the background art with effective solutions.

[0024] In a preferred embodiment of this novel experimental design, the inverter power supply circuit includes a switching power supply circuit and a full-bridge inverter circuit; the logic control output terminal of the main control chip includes a switching control output terminal and an inverter control output terminal. The switching control receiver of the switching power supply circuit is connected to the switching control output of the main control chip, and the inverter control receiver of the full-bridge inverter circuit is connected to the inverter control output. The power output terminal of the switching power supply circuit is connected to the power input terminal of the full-bridge inverter circuit, and the power input terminal of the switching power supply circuit is connected to the power supply terminal of the lithium battery pack.

[0025] In a preferred embodiment of this novel experimental design, the switching power supply circuit, such as... Figure 1 The following are included: The second pin of the driver chip U1 is connected to the sixth pin DR1 of the main control chip U0, and the fourth pin of the driver chip U1 is connected to the ninth pin DR2 of the main control chip. The first MOSFET MOS1 has its gate connected to the fifth pin of the driver chip U1 via the first resistor R1. The gate of the second MOSFET MOS2 is connected to the seventh pin of the driver chip through the second resistor R2. The source of the second MOSFET MOS2 is connected to the source of the first MOSFET MOS1. The drain of the second MOSFET MOS2 and the drain of the first MOSFET MOS1 are connected in series with the third resistor R3 and the first capacitor C1. Transformer T1 has its first terminal connected to the drain of the first MOSFET MOS1, its fifth terminal connected to the drain of the second MOSFET MOS2, its tenth terminal connected to the cathode of the first diode D1 and the anode of the second diode D2, and its ninth terminal connected to the cathode of the third diode D3 and the anode of the fourth diode D4. The anode of the third diode D3 is connected to the anode of the first diode D1, and the cathode of the second diode D2 is connected to the cathode of the fourth diode D4. A fourth resistor R4 and a second capacitor C2 are connected in parallel between the anode of the first diode D1 and the cathode of the fourth diode D4. The third MOSFET MOS3 has its source connected to the second, third, and fourth terminals of transformer T1. The fifth resistor R5 is connected in series between the gate and drain of the third MOSFET MOS3. The drain of the third MOSFET MOS3 is connected to the 18V power supply terminal of the lithium battery pack and to the 18.5V power supply of the switching circuit through the sixth resistor R6. The anode of the first diode D1 is connected to the power input terminal HV of the full-bridge inverter circuit.

[0026] The switching power supply circuit also includes several components for short-circuit protection, such as the resistor connected to the base of the first MOSFET MOS1, the resistor connected to the second and fourth pins of the driver chip U1, and the diode connected to the sixth pin of the transformer T1, etc., which will not be listed one by one in this embodiment.

[0027] Specifically, the main task of the switching power supply circuit is to convert the 18V DC power from the lithium battery pack into the high-voltage DC (HV) required by the full-bridge inverter circuit, as well as other low-voltage power supplies. It is a push-pull switching power supply.

[0028] The core components include: Driver chip U1: This is the core of the PWM (Pulse Width Modulation) control. It receives the switching control signals DR1 and DR2 from the main control chip U0 and outputs two alternating PWM signals to drive the MOSFETs.

[0029] MOSFETs MOS1 and MOS2: These are power switching transistors. The PWM signal output from the driver chip U1 drives their gates, causing them to alternately turn on and off.

[0030] Transformer T1: This is a key isolation and transformation component. When MOS1 and MOS2 are turned on alternately, they will generate alternating current on the primary side of transformer T1 (connected to MOS1 and MOS2), causing a corresponding voltage to be generated on the secondary side (connected to D1-D4).

[0031] Rectifier and filter circuit (D1-D4, C2, R4): The secondary output of transformer T1 is alternating current (AC). D1-D4 (forming a full-wave rectifier bridge) rectifies the AC into direct current (DC), while C2 and R4 filter the output, providing a relatively stable DC voltage. This output voltage is the power input (HV) of the full-bridge inverter circuit.

[0032] MOSFET MOS3: This is a high-side switch used to control the enable of the entire switching power supply circuit. It receives a control signal from the power supply latch-up circuit (from the collector of Q1) and is connected to the 18.5V power supply. When MOS3 is turned on, the 18.5V power supply reaches the drain of MOS3 through R6 and R5, serving as the input to the entire switching power supply.

[0033] In a preferred embodiment of this novel experimental design, the inverter power supply circuit further includes a power supply self-locking circuit, as shown in the example below. Figure 1 The following are included: The collector of the first transistor Q1 is connected to the gate of the third MOSFET MOS3 through the seventh resistor R7. The emitter and base of the first transistor Q1 are connected in series with the eighth resistor R8. The base of the first transistor Q1 is connected to the power enable pin EN-POW of the main control chip U0 through the ninth resistor R9.

[0034] Specifically, in this embodiment, the power supply self-locking circuit includes Q1, R6, R7, R8, and R9. The purpose of this circuit is to self-lock and keep MOS3 on after the main control chip U0 issues an enable signal (EN-POW), even if the EN-POW signal disappears. Q1 (transistor) is controlled by the EN-POW signal. When EN-POW is high, Q1 is on, and its collector voltage is pulled low, thereby driving MOS3 to turn on. Once MOS3 is on, it provides positive feedback to the base of Q1 through R5 / R7, keeping it on and achieving self-locking.

[0035] The working process of a switching power supply circuit includes: Start-up: The main control chip U0 sends an EN-POW signal, and Q1 is turned on.

[0036] Power supply: After Q1 is turned on, MOS3 is turned on, and the 18V power supply is connected to the main circuit of the switching power supply.

[0037] PWM drive: U1 outputs a PWM wave based on the DR1 and DR2 signals, which alternately drives MOS1 and MOS2.

[0038] Transformer rectification: The switching action of MOS1 / MOS2 generates a changing magnetic field on the primary side of T1, which induces AC current on the secondary side. After rectification by D1-D4 and filtering by C2, HV DC output is generated.

[0039] Self-locking: After MOS3 is turned on, it provides positive feedback to the base of Q1 through R5 / R7. Even if the EN-POW signal disappears, MOS3 will remain on, maintaining the operation of the switching power supply until the system needs to be shut down.

[0040] In a preferred embodiment of this novel experimental design, the full-bridge inverter circuit is as follows: Figure 2 The following are included: The first optocoupler OC1 has its first and second pins connected to the twelfth pin DR3 of the main control chip U0 via the tenth resistor R10 and the eleventh resistor R11, respectively. The second optocoupler OC2 has its first and second pins connected to the thirteenth pin of the main control chip U0 via the twelfth resistor R12 and the thirteenth resistor R13, respectively. The base of the second transistor Q2 is connected to the third pin of the first optocoupler OC1 through the fourteenth resistor R14, and the emitter and base of the second transistor Q2 are connected in series with the fifteenth resistor R15. The base of the third transistor Q3 is connected to the third pin of the second optocoupler OC2 through the sixteenth resistor R16, and the emitter and base of the third transistor Q3 are connected in series with the seventeenth resistor R17. The first terminal of the current inverter bridge T2 is connected to the collector of the second transistor Q2 through the eighteenth resistor R18. The midpoint of the first bridge arm of the current inverter bridge T2 is connected to one end of the third capacitor C3 and the cathode of the fifth diode D5. The anode of the fifth diode D5 is connected to the first terminal of the current inverter bridge T2. The other end of the third capacitor C3 is connected to one end of the nineteenth resistor R19 and the anode of the sixth diode D6. The other end of the nineteenth resistor R19 is connected to the collector of the second transistor Q2. The cathode of the sixth diode is connected to the inverter operating power supply 15V. The second terminal of the current inverter bridge T2 is connected to one end of the twentieth resistor R20 and the cathode of the seventh diode D7, and the other end of the twentieth resistor R20 and the anode of the seventh diode D7 are connected to the third terminal of the first optocoupler OC1. The third terminal of the current inverter bridge T2 is connected to the collector of the third transistor Q3 through the twenty-first resistor R21. The midpoint of the second bridge arm of the current inverter bridge T2 is connected to one end of the fourth capacitor C4 and the cathode of the eighth diode D8. The anode of the eighth diode D8 is connected to the third terminal of the current inverter bridge T2. The other end of the fourth capacitor C4 is connected to one end of the twenty-second resistor R22 and the anode of the fourteenth diode D14. The other end of the twenty-second resistor R22 is connected to the collector of the third transistor Q3. The cathode of the fourteenth diode D14 is connected to the inverter operating power supply 15V. The fourth terminal of the current inverter bridge T2 is connected to one end of the twenty-third resistor R23 and the cathode of the ninth diode D9, and the other end of the twenty-third resistor R23 and the anode of the ninth diode D9 are connected to the third terminal of the second optocoupler OC2. The current input terminal of the current inverter bridge T2 is connected to the current output terminal HV of the power switch circuit; The midpoint A1 of the first bridge arm and the midpoint A2 of the second bridge arm of the current inverter T2 serve as the external output terminals of the inverter power supply circuit.

[0041] Specifically, the full-bridge inverter circuit in this embodiment is an inverter based on a full-bridge topology. Its core task is to convert high-voltage direct current (HV) from the switching power supply into alternating current and output it through the midpoints of the two bridge arms (A1 and A2).

[0042] The circuit components include: Output signals of the main control chip (U0): DR3: Used to control the first drive signal.

[0043] DR4: Used to control the second drive signal.

[0044] Optical couplers (OC1, OC2) provide high- and low-voltage isolation, ensuring the safety of the main control chip and transmitting control signals.

[0045] like Figure 3 As shown, the DR3 and DR4 signals of the main control chip drive the internal light-emitting diodes of OC1 and OC2 through resistors R10 / R11 and R12 / R13, respectively. The optical signals are received by the internal phototransistors, thereby controlling the conduction or cutoff of their output terminals.

[0046] The output of OC1 controls Q2. The output of OC2 controls Q3.

[0047] Transistors (Q2, Q3) act as buffers and driver stages, receiving signals from the optocoupler and driving the gates of the power MOSFETs. The bases of Q2 and Q3 receive drive signals from OC1 and OC2. Bias and current limiting are achieved through resistors R14 / R15 and R16 / R17. The signals output from their collectors are used to drive the power MOSFETs (MOS4 / MOS5 and MOS6 / MOS7).

[0048] Preferably, the current inverter bridge T2 is as follows: Figure 2 The following are included: The gate of the fourth MOSFET MOS4 is connected to the collector of the second transistor Q3 through the eighteenth resistor R18. The fifth MOSFET, MOS5, has its gate connected to one end of the twentieth resistor, R20. The gate of the sixth MOSFET MOS6 is connected to the collector of the third transistor Q3 through the twenty-first resistor R21. The seventh MOSFET, MOS7, has its gate connected to one end of the twenty-third resistor, R23. The drains of the fourth MOSFET MOS4 and the sixth MOSFET MOS6 are connected to the current output terminal HV of the power switch circuit. The connection point between the source of the fourth MOSFET MOS4 and the drain of the fifth MOSFET MOS5 is taken as the midpoint AC1 of the first arm of the current inverter bridge T2, and the connection point between the source of the sixth MOSFET MOS6 and the drain of the seventh MOSFET MOS7 is taken as the midpoint AC2 of the second arm of the current inverter bridge T2.

[0049] In this embodiment, the current inverter bridge (T2, including MOS4, MOS5, MOS6, and MOS7) is the main body for realizing the inverter function, and it consists of four power MOSFETs. MOS4 and MOS6 form one bridge arm (upper bridge arm), and MOS5 and MOS7 form the other bridge arm (lower bridge arm).

[0050] The input HV (high voltage DC) of the current inverter bridge is connected to the drain of the upper bridge arm MOSFET (MOS4, MOS6), and the source of the lower bridge arm MOSFET (MOS5, MOS7) is grounded (SGND).

[0051] Output of the current inverter bridge: The midpoints (AC1, AC2) of the two bridge arms are the AC output terminals of the inverter.

[0052] The gates of MOS4 and MOS6 are driven by the collectors of Q2 and Q3 via R18 and R21 (and associated protection diodes D5 / D8 and capacitors C3 / C4). The gates of MOS5 and MOS7 are directly driven by the output of the optocoupler via R20 and R23 (and associated protection diodes D7 / D9) (or via some RC components).

[0053] It also includes auxiliary components (R18-R23, D5-D9, D14, C3, C4): Resistors (R18-R23) are used for current limiting and voltage regulation of drive signals.

[0054] Diodes (D5-D9, D14): D5, D8: Freewheeling diodes. When the MOSFET is turned off, they provide a current path for the inductive load and absorb induced voltage.

[0055] D7, D9: Zener diodes, which may be used to protect the gate of a MOSFET from overvoltage.

[0056] D14: Reverse protection diode, connected to a 15V power supply, used to provide protection in certain situations or to provide a reference voltage for the drive circuit.

[0057] Capacitors (C3, C4): Gate bypass capacitors, used to stabilize the MOSFET gate voltage and prevent oscillation.

[0058] A full-bridge inverter circuit converts the input DC high voltage (HV) into AC output by precisely controlling the switching sequence of four power MOSFETs (MOS4, MOS5, MOS6, MOS7). Its operation can be divided into several stages: Drive and Isolation: The main control chip U0 outputs PWM signals through DR3 and DR4, which are isolated by optocouplers OC1 / OC2, and then driven by transistors Q2 / Q3 (or directly by the optocoupler output) to drive the gate of the MOSFET.

[0059] Alternating conduction: First state: MOS4 and MOS7 are on, MOS6 and MOS5 are off. Current flows from HV through MOS4, through the load (from A1 to A2), and then back to SGND from MOS7. At this time, A1 is high and A2 is low (relative to SGND).

[0060] Second state: MOS6 and MOS5 are on, MOS4 and MOS7 are off. Current flows from HV through MOS6, through the load (from A2 to A1), and then back to SGND from MOS5. At this time, A2 is high and A1 is low (relative to SGND).

[0061] By rapidly switching between these two states, a square wave or near-sine wave AC voltage is generated between A1 and A2. The duty cycle and frequency of the PWM signal determine the magnitude and frequency of the output voltage.

[0062] At the moment the MOSFET switches, the freewheeling diodes (D5, D8) conduct, providing a current path for the inductive load and protecting the MOSFET from damage caused by transient overvoltage. Other protection diodes and capacitors also play a corresponding protective and stabilizing role.

[0063] The midpoints A1 and A2 of the bridge arm are the AC output terminals, and the voltage difference between them constitutes the output AC power.

[0064] Interlocking of upper and lower bridge arms: To prevent shoot-through (i.e., both MOSFETs on the same bridge arm conducting simultaneously, causing HV to short-circuit directly to SGND), a dead time is usually added to the control logic. This ensures that at the instant of switching between upper and lower bridge arms, the MOSFET of one bridge arm is turned off first, and then the MOSFET of the other bridge arm is turned on. The MOSFET gate drive circuit (including optocouplers, transistors, resistors, capacitors, and diodes) is crucial for ensuring fast and reliable switching of the MOSFETs.

[0065] In summary, this full-bridge inverter circuit is a standard power conversion circuit that utilizes the switching characteristics of MOSFETs to convert high-voltage DC into a controllable AC output.

[0066] Specifically, the logic control input terminals of the inverter power supply circuit are specific pins of the main control chip (U0), including: The main control chip's switch control output terminals DR1 and DR2 are connected to the input pins (pin 2 and pin 4) of the driver chip U1 in the switching power supply circuit.

[0067] The inverter control output terminals (DR3, DR4) of the main control chip U0 are connected to the input pins of the optocouplers (OC1, OC2) in the full-bridge inverter circuit.

[0068] The power input terminal of the inverter power supply circuit is the drain of the third MOSFET MOS3 in the switching power supply circuit. This point is directly connected to the 18V power supply terminal of the lithium battery pack.

[0069] The switching start terminal of the inverter power supply circuit is the power enable pin EN-POW of the main control chip U0. This pin is connected to the base of the first transistor Q1 in the power self-locking circuit through the ninth resistor R9.

[0070] Preferably, the inverter power supply circuit also includes an overcurrent detection circuit J10, such as... Figure 4 The following are included: The twenty-fourth resistor R24 ​​is connected to the source of the first MOSFET MOS1 at one end, and the other end of the twenty-fourth resistor R24 ​​is connected to one end of the twenty-fifth resistor R25 and one end of the twenty-sixth resistor R26 at the other end. The other end of the twenty-fifth resistor R25 is connected to the overcurrent power supply. Operational amplifier OA has its non-inverting input connected to one end of the 26th resistor R26 and the 6th capacitor C6, with the other end of the 6th capacitor C6 grounded. Its inverting input is connected to one end of the 27th resistor R27, one end of the 28th resistor R28, and the other end of the 7th capacitor C7. Its output is connected to the other end of the 28th resistor R28, the other end of the 7th capacitor C7, one end of the 29th resistor R29, and one end of the 30th resistor R30, with the other end of the 27th resistor R27 and the other end of the 30th resistor R30 grounded. The other end of resistor R29 is connected to the overcurrent detection pin IS of the main control chip.

[0071] Specifically, the main function of the overcurrent detection circuit in this embodiment is to monitor the current in the circuit and send a signal to the main control chip U0 when the current exceeds the set threshold, so that the main control chip can take corresponding protection measures (e.g., turn off the switching power supply or inverter).

[0072] Its circuit composition includes: The 24th resistor, R24, is connected to the source of the first MOSFET, MOS1. MOS1 is a power switch in a switching power supply circuit. According to Ohm's law (V=IR), when current flows through R24, a voltage drop is generated across it. The magnitude of this voltage drop is proportional to the current flowing through MOS1.

[0073] The voltage divider and filter network (composed of R25, R26, and C6) is used to divide and filter the voltage signal generated by R24 and send it to the input of the operational amplifier (OA).

[0074] The voltage across R24 (which is proportional to the current) is fed into R26 and C6.

[0075] R26 and C6 together form a low-pass filter that filters out high-frequency noise in the signal, retaining only relatively stable DC or low-frequency components.

[0076] R25 is used to divide the signal and connect it to an overcurrent operating power supply of 5V.

[0077] The operational amplifier (OA) acts as a voltage comparator, comparing a filtered and divided detection signal with a reference voltage. The non-inverting input (+) is connected to the node between R26 and C6, receiving the processed current signal from R24. The inverting input (-) is connected to the voltage divider and feedback network of R27, R28, and C7. R27 and R30 are connected to ground, and R28 and C7 form a feedback loop. This network is used to set the comparator's threshold voltage. The output is connected to R29 and R30. R29 is a current-limiting resistor that transmits the operational amplifier's output signal to the overcurrent detection pin IS of the main control chip. Resistor R30 is used to stabilize the output.

[0078] Its workflow is as follows: During normal operation: the current flowing through MOS1 is normal, and the voltage drop generated by R24 is small. After being processed by R26 and C6, it is sent to the non-inverting input of OA. If this voltage is lower than the threshold voltage set at the inverting input of OA, the output (IS) of OA will be in a certain state (e.g., low level or a certain voltage value).

[0079] Overcurrent Incident: When an overcurrent occurs in the circuit (e.g., a load short circuit or power device failure), the current flowing through MOS1 will increase sharply. R24 Voltage Increase: According to Ohm's law, the voltage drop across R24 will increase significantly. This increased voltage signal is filtered by R26 and C6 and then sent to the non-inverting input of OA. When it exceeds the reference threshold voltage at the inverting input of OA, the output state of OA will change (e.g., from low to high, or from one voltage to another).

[0080] The change signal output by the OA is transmitted to the IS pin of the main control chip through R29. The main control chip (U0) receives the signal on the IS pin, identifies an overcurrent condition, and can then execute protection actions, such as: shutting down the switching power supply (stopping HV generation), stopping the drive signal of the full-bridge inverter, and protecting the power devices.

[0081] The battery power is converted into high-voltage direct current (HV) through components such as MOS1, MOS2, and T1. R24, located at the source of MOS1, is an important monitoring point for the operating current of the switching power supply. The full-bridge inverter receives the HV DC power and converts it into AC output. The overcurrent detection circuit monitors the current flowing through MOS1 (i.e., the input current of the switching power supply) in real time. If the current is too high, an alarm is immediately sent to the main control chip.

[0082] This overcurrent detection circuit uses an operational amplifier as a voltage comparator and converts the current signal into a voltage signal through R24. By adjusting the parameters of components such as R27, R28, and C7, the overcurrent detection threshold can be set.

[0083] In a preferred embodiment of this invention, the USB power supply circuit is as follows: Figure 5 The following are included: USB driver chip U2, the first pin of USB driver chip U2 is connected to one end of the fiftieth resistor R50, one end of the thirty-first resistor R31, and one end of the eighth capacitor C8. The other end of the thirty-first resistor R31 is connected to one end of the ninth capacitor C9 and one end of the tenth capacitor C10. The fifth pin of the USB driver chip U2 is connected to the other end of the eighth capacitor C8, the other end of the fiftieth resistor R50, the other end of the ninth capacitor C9, and the other end of the tenth capacitor C10. The Type-C interface is connected to pins 12, 13, 14, 15, and 16, and also to pin 5 of the USB driver chip U2, one end of capacitor C11 (eleventh), one end of capacitor C12 (twelfth), the cathode of the first transient voltage suppressor diode TVS1, the cathode of the second transient voltage suppressor diode TVS2, and pin 1 of the Type-C interface. The other end of the eleventh capacitor C11 is connected to the anode of the first transient voltage suppressor diode TVS1 and the fourth pin of the Type-C interface. The other end of the eleventh capacitor C11 is also connected to the first pin of the Type-C interface through the thirty-second resistor R32. The other end of the twelfth capacitor C12 is connected to the anode of the second transient voltage suppressor diode TVS2 and the tenth pin of the Type-C interface. The other end of the twelfth capacitor C12 is also connected to the first pin of the Type-C interface through the thirty-third resistor R33. The second and eleventh pins of the Type-C interface are connected to the third pin of the USB driver chip, and also to one end of the thirty-fourth resistor R34. The other end of the thirty-fourth resistor R34 is connected to the eighth pin of the USB driver chip. The USB interface JUSB has a thirteenth capacitor C13 connected in series between the first and fourth pins. The first pin of the USB interface is also connected to the fourth pin of the USB driver chip U2 and one end of the thirty-fifth resistor R35. The other end of the thirty-fifth resistor R35 is connected to the second pin of the USB driver chip U2. The sixth pin of the USB driver chip U2 is connected to the first pin of the common mode inductor L and one end of the thirteenth capacitor C13, the fourteenth capacitor C14, and the fifteenth capacitor C15. The fifth pin of the USB driver chip U2 is connected to the second pin of the common mode inductor L and the other end of the thirteenth capacitor C13, the fourteenth capacitor C14, and the fifteenth capacitor C15. A sixteenth capacitor C16 is connected in series between the third and fourth pins of the common-mode inductor L. The third pin of the common-mode inductor L is connected to the source of the eighth MOSFET MOS8. The fourth pin of the common-mode inductor L is connected to the USB overcurrent detection circuit J20. The detection output terminal of the USB overcurrent detection circuit J20 is connected to the sixteenth pin IS-usb AD of the main control chip. The circuit structure of the USB overcurrent detection circuit J20 is the same as that of the overcurrent detection circuit J10, and will not be described again here.

[0084] The gate and drain of the eighth MOSFET MOS8 are connected in series with the thirty-sixth resistor R36. The drain of the eighth MOSFET MOS8 is connected to the source (i.e., the DC connection) of the third MOSFET MOS3. The gate of the eighth MOSFET MOS8 is connected to one end of the thirty-seventh resistor R37. The other end of the thirty-seventh resistor R37 is connected to the collector of the fourth transistor Q4. The emitter and base of the fourth transistor Q4 are connected in series with the thirty-eighth resistor R38 and grounded. The base of the fourth transistor Q4 is also connected to the fifteenth pin usb-POW of the main control chip through the thirty-ninth resistor R39.

[0085] The Type-C interface outputs 5V 3.1A current, and the USB JUSB interface outputs 5V 2.4A current. Both are currents after being transformed by a current transformer, as shown in the transformer circuit. Figure 8 As shown, the DC current output from the lithium battery is transformed twice from 12V to 5V to power various other circuits, as well as to serve as the output current for the Type-C and USB interfaces.

[0086] Specifically, in this embodiment, the USB power supply circuit is mainly responsible for obtaining power from the lithium battery pack and providing a standard 5V output for the Type-C interface and the USB interface, while also having overcurrent protection.

[0087] Its core components include: The USB driver chip U2 is the brain behind communication and power management between the USB and Type-C interfaces. It is responsible for communicating with the Type-C interface: pins 2 and 11 of the Type-C interface are connected to pins 3 and 8 of U2 via R34 to negotiate power supply capabilities (such as 5V / 3.1A or 5V / 2.4A).

[0088] The USB power supply is managed by controlling MOSFET MOS8.

[0089] The Type-C interface supports reversible insertion, is universal for both data and power supply, and outputs 5V 3.1A.

[0090] JUSB is a traditional USB interface that typically supports D+ / D- data cables and 5V power supply, outputting 5V 2.4A.

[0091] MOSFET MOS8: As a high-side switch, controlled by U2 and Q4 (transistors), it is used to turn USB power on or off. The drain is connected to DC (possibly 12V), and the source is connected to the common-mode inductor L and the USB overcurrent detection circuit J20.

[0092] The common-mode inductor L and filter capacitors (C13, C14, C15, C16) are used to suppress common-mode noise, improve the quality of USB signals, and participate in power supply filtering.

[0093] The USB overcurrent detection circuit J20 monitors the current flowing to the USB interface (JUSB). Once the current exceeds a set threshold (e.g., 2.4A), it sends a signal to the IS-usb AD pin of the host chip. The circuit structure is identical to that of the overcurrent detection circuit J10, also using a resistor connected to the source of MOS8 to convert the current into a voltage, which is then compared by an operational amplifier before being output to the host chip.

[0094] Transistor Q4 and associated resistors (R36, R37, R38, R39) work together with U2 to control the gate of MOS8. Q4 acts as a level shifter or driver.

[0095] The USB-POW signal from the main control chip (via R39) controls the base of Q4, and the collector output signal of Q4 drives the gate of MOS8 (via R36) through R37. This determines whether MOS8 is turned on, thereby controlling the USB power supply to be turned on / off.

[0096] Transient voltage suppressor diodes (TVS1, TVS2) protect the Type-C interface from overvoltage transients, preventing damage to the interface from electrostatic discharge or other surges.

[0097] When a Type-C device is plugged in, the pins of the Type-C interface communicate with the USB driver chip U2 via R34.

[0098] Based on the negotiation results (e.g., the device requires 5V / 3.1A), U2 controls the switching of MOS8 and may adjust the internal power management strategy to provide the required power supply.

[0099] The Type-C interface will output a 5V voltage, which is controlled by U2 through MOS8.

[0100] The main control chip's USB-POW signal controls the gate of MOS8 through Q4 and R37, R36, thereby controlling the 5V power supply of the USB interface (JUSB) to turn on and off.

[0101] U2 also participates in controlling the power supply to the JUSB, ensuring its output is 5V / 2.4A.

[0102] The common-mode inductor L and capacitors C13-C16 are used for filtering to improve the USB signal quality.

[0103] The USB overcurrent detection circuit J20 monitors the current flowing through MOS8 (i.e., the USB power supply current). When the current of the USB interface (JUSB) exceeds 2.4A, J20 detects the abnormality and sends a signal to the IS-usb AD pin of the host control chip. Upon receiving the signal, the host control chip will shut down MOS8 and cut off the USB power supply to protect the device.

[0104] TVS1 and TVS2 provide transient voltage protection on the Type-C interface.

[0105] It utilizes the USB driver chip U2 to handle the complex communication and power negotiation of the Type-C interface, controls the power switch through MOSFET MOS8, and integrates overcurrent protection to ensure the normal and safe operation of USB devices. As a more advanced interface, the Type-C interface supports higher power supply capabilities and more flexible negotiation mechanisms.

[0106] In a preferred embodiment of this invention, a main control chip startup circuit is also included, such as... Figure 6 The following are included: Start button K1. The first end of start button K1 is connected to the 18V power supply terminal of the lithium battery pack. The other end of start button K1 is connected to the cathode of the tenth diode D12 and one end of the fortieth resistor R40. The other end of the fortieth resistor R40 is connected to one end of the forty-first resistor R41, one end of the seventeenth capacitor C17 and the fifth pin KEY1 of the main control chip. The other end of the forty-first resistor R41 and the other end of the seventeenth capacitor C17 are grounded. The second pin of the startup chip U3 is connected to the anode of the eleventh diode D12 through the forty-second resistor R42. The second pin of the startup chip U3 is also connected to the first pin of the startup chip U3 and grounded through the seventeenth capacitor C17. The third pin of the startup chip U3 is connected to one end of the eighteenth capacitor C18 and the nineteenth capacitor C19 respectively. The other ends of the eighteenth capacitor C18 and the nineteenth capacitor C19 are grounded. The third pin of the startup chip U3 is also connected to the twentieth pin of the main control chip U3. The third pin of the startup chip U3 is also connected to the fourth pin LD0+5V of the main control chip U0 through the forty-third resistor R43.

[0107] Specifically, in this embodiment, the main control chip startup circuit provides a reliable startup mechanism for the entire system and provides a stable 5V power supply for some key low-voltage chips.

[0108] Start button K1: This is a physical button for manually starting the system. One end is connected to the 18V lithium battery, and the other end is connected to the cathode of D12, R40, and R42.

[0109] Diodes D12 and D13 are used; D12 prevents reverse voltage. When K1 is pressed, 18V voltage passes through D12, providing voltage to the +VC point.

[0110] D13 isolates the 18V DC connection from the +VC point.

[0111] R40, R41, and C17 together form an RC filter network to filter the signal at the +VC point and provide it to the KEY1 pin of the main control chip.

[0112] R42 is connected to the Vin pin of U3, possibly for current limiting or providing a reference voltage.

[0113] Capacitor C17 is a filter capacitor used to smooth the voltage at the +VC point and reduce ripple in the signal.

[0114] The startup chip U3 receives control signals from K1 and the main control chip, and outputs a stable 5V power supply (LD0+5V).

[0115] Pin 3 (Vout) of U3 is also connected to the LD0+5V pin of the main control chip U0. This is a feedback mechanism used to monitor the output voltage. At the same time, Pin 3 of U3 is also connected to pin 4 of the main control chip U0 via R43.

[0116] The main control chip (U0) receives the start signal from K1 and the RC filter circuit via KEY1. The main control chip determines whether to start by detecting the voltage change on the KEY1 pin.

[0117] LD0+5V (Pin 4) receives the 5V power supply output from U3.

[0118] The working principle includes: Press the start button K1. 18V voltage is applied to the +VC point through D12. The voltage at the +VC point is filtered by R40, R41, and C17 before being sent to the KEY1 pin of the main control chip. The main control chip detects the voltage change at the KEY1 pin, recognizes it as a start signal, and begins executing the start process.

[0119] U3 (LDO) receives the voltage from the +VC point and is controlled by the main control chip (U0) (via R43 and KEY2) to begin outputting a stable 5V power supply (LD0+5V). The 5V power supply output by U3 powers other low-voltage components in the system and provides power to the USB circuitry (5V / 3.1A and 5V / 2.4A).

[0120] The Vout pin of U3 is connected to the LD0+5V pin of the main control chip for monitoring and adjusting the output voltage.

[0121] Specifically, the power input terminal of the USB power supply circuit is the drain of the eighth MOSFET MOS8 in the USB power supply circuit. This point is connected to a node called DC, which ultimately originates from the power supply terminal of the lithium battery pack.

[0122] The USB power supply circuit's power-on switch is the USB power-on pin usb-POW of the main control chip U0. This pin is connected to the base of the fourth transistor Q4 in the USB power supply circuit through resistor R39.

[0123] In a preferred embodiment of this invention, the LED lighting circuit is as follows: Figure 7 The following are included: LED start button K2, one end of LED start button K2 is connected to the 18V power supply terminal of the lithium battery pack, the other end of LED start button K2 is connected to one end of the forty-fourth resistor R44 and the cathode of the twelfth diode D12, the other end of the forty-fourth resistor R44 is connected to one end of the forty-fifth resistor R45 and one end of the twentieth capacitor C20, the other end of the forty-fifth resistor R45 and the other end of the twentieth capacitor C20 are grounded, and the other end of the forty-fourth resistor R44 is also connected to the eleventh pin KEY2 of the main control chip U0; The anode of the twelfth diode D12 is also connected to the anode of the thirteenth diode D13 and one end of the forty-second resistor R42 (i.e., the +VC connection point). The cathode of the thirteenth diode D13 is connected to the power input terminal of the USB circuit (i.e., the DC connection point). The cathodes of the first LED1 and the second LED2 are connected to the LED power supply of 5V 3.1A. The anodes of the first LED1 and the second LED2 are connected to the drain of the ninth MOS transistor MOS9 through resistors R46 (forty-sixth) and R47 (forty-seventh) respectively. Resistor R48 (forty-eighth) is connected in series between the source and gate of the ninth MOS transistor MOS9 and grounded. The gate of the ninth MOS transistor MOS9 is connected to the LED start-up terminal EN-LED of the main control chip through resistor R49 (forty-ninth).

[0124] Specifically, in this embodiment, the LED lighting circuit controls the LED light to turn on and off via an LED start button K2, and provides the LED with the required 5V power supply.

[0125] LED start button K2: Used to turn LED lighting on or off. One end is connected to an 18V lithium battery, and the other end is connected to R44, D12 (cathode), and KEY2.

[0126] Diodes D12 and D13 function similarly to D12 and D13 in the main control chip's startup circuit, serving to isolate and prevent reverse voltage. D13 is connected to the DC power input terminal of the USB circuit.

[0127] R44, together with D12, K2, and KEY2, forms a control signal, which is sent to the KEY2 pin of the main control chip. R45 is used for current limiting or to provide a reference.

[0128] Capacitor C20 is a filter capacitor used to smooth the signal on the KEY2 pin.

[0129] LED1 and LED2 are light-emitting diodes that provide illumination. Their cathodes are connected to a 5V 3.1A power supply (from the USB Type-C interface), and their anodes are connected to the drain of MOS9 through resistors R46 and R47.

[0130] MOSFET MOS9: Acts as a low-side switch, controlling the current path of the LEDs. Connected to the anodes of LED1 and LED2 (through current-limiting resistors R46 / R47). The source is grounded. The gate is connected to the EN-LED pin of the main control chip via R49, and then grounded after being connected in series with R48.

[0131] KEY2 (Pin 11) of the main control chip U0: Receives signals from K2 and is used to control the enable of the LED circuit.

[0132] The main control chip U0's EN-LED (Pin 15) outputs a control signal to the gate of MOS9, directly controlling the LED's on / off state.

[0133] Press the LED start button K2. 18V voltage is applied to the KEY2 pin of the main control chip through K2, R44, and D12, simultaneously providing voltage to the +VC point. The main control chip detects the voltage change on the KEY2 pin and identifies it as a start / stop command for LED lighting. If it is an start command, the main control chip outputs a high-level signal to the EN-LED pin. The high-level signal output from the EN-LED pin is applied to the gate of MOS9 through R49. MOS9 conducts, and the 5V 3.1A power supply provides current to LED1 / LED2 through R46 / R47, lighting the LEDs. If the EN-LED output is low, MOS9 is cut off, and the LEDs are off. The main control chip startup circuit provides a button start function and a stable 5V power supply to the system. It controls the startup chip U3 to operate by detecting the button and power signals, thus initializing the system.

[0134] The LED lighting circuit uses a separate LED start button and a main control chip to switch the LED on and off. It utilizes a MOSFET as a low-side switch to precisely control the LED current and provides the LED with 5V power via a Type-C interface.

[0135] Both the main control chip startup circuit and the LED lighting circuit rely on the input signals (KEY1, KEY2, EN-LED) of the main control chip (U0) to control the hardware actions, reflecting the linkage control between software and hardware.

[0136] Specifically, the power input terminal of the LED lighting circuit is the cathode of the thirteenth diode D13 in the LED lighting circuit. This point is connected to a node called DC, which originates from the power supply terminal of the lithium battery pack.

[0137] The lighting start-up terminal of the LED lighting circuit is the LED start-up pin EN-LED of the main control chip U0. This pin is connected to the gate of the ninth MOS transistor MOS9 in the LED lighting circuit through resistor R49.

[0138] The above are merely preferred embodiments of this experimental novel and do not limit the implementation methods and protection scope of this experimental novel. Those skilled in the art should realize that any equivalent substitutions and obvious changes made using the content of this specification and figures should be included within the protection scope of this experimental novel.

Claims

1. A DC-AC inverter with a lithium battery pack, characterized in that, include: An inverter power supply circuit, wherein the logic control input terminal of the inverter power supply circuit is connected to the logic control output terminal of the main control chip, the power input terminal of the inverter power supply circuit is connected to the power supply terminal of the lithium battery pack, and the switch start terminal of the inverter power supply circuit is connected to the inverter start terminal of the main control chip; USB power supply circuit, wherein the power input terminal of the USB power supply circuit is connected to the power supply terminal of the lithium battery pack, and the switch start terminal of the USB power supply circuit is connected to the USB start terminal of the main control chip; The LED lighting circuit has its power input terminal connected to the power supply terminal of the lithium battery pack, and its lighting start terminal connected to the LED start terminal of the main control chip.

2. The DC-AC inverter according to claim 1, characterized in that, The inverter power supply circuit includes a switching power supply circuit and a full-bridge inverter circuit; the logic control output terminal of the main control chip includes a switching control output terminal and an inverter control output terminal. The switching control receiving terminal of the switching power supply circuit is connected to the switching control output terminal of the main control chip, and the inverter control receiving terminal of the full-bridge inverter circuit is connected to the inverter control output terminal. The power output terminal of the switching power supply circuit is connected to the power input terminal of the full-bridge inverter circuit, and the power input terminal of the switching power supply circuit is connected to the lithium battery pack.

3. The DC-AC inverter according to claim 2, characterized in that, The switching power supply circuit includes: A driver chip, wherein the second pin of the driver chip is connected to the sixth pin of the main control chip, and the fourth pin of the driver chip is connected to the ninth pin of the main control chip; The first MOSFET, the gate of which is connected to the fifth pin of the driver chip via a first resistor; The second MOSFET has its gate connected to the seventh pin of the driver chip via a second resistor, its source connected to the source of the first MOSFET, and a third resistor and a first capacitor connected in series between the drain of the second MOSFET and the drain of the first MOSFET. A transformer, wherein the first connection terminal of the transformer is connected to the drain of the first MOSFET, the fifth connection terminal of the transformer is connected to the drain of the second MOSFET, the tenth connection terminal of the transformer is connected to the cathode of the first diode and the anode of the second diode, the ninth connection terminal of the transformer is connected to the cathode of the third diode and the anode of the fourth diode, the anode of the third diode is connected to the anode of the first diode, and the cathode of the second diode is connected to the cathode of the fourth diode. A fourth resistor and a second capacitor are connected in parallel between the anode of the first diode and the cathode of the fourth diode; The third MOSFET has its source connected to the second, third, and fourth terminals of the transformer. A fifth resistor is connected in series between the gate and drain of the third MOSFET. The drain of the third MOSFET is connected to the lithium battery pack and to the power supply of the switching circuit through a sixth resistor. The anode of the first diode is connected to the power input terminal of the full-bridge inverter circuit.

4. The DC-AC inverter according to claim 3, characterized in that, The inverter power supply circuit also includes a power supply self-locking circuit, which includes: The first transistor has its collector connected to the gate of the third MOS transistor via a seventh resistor. An eighth resistor is connected in series between the emitter and base of the first transistor. The base of the first transistor is connected to the power enable pin of the main control chip via a ninth resistor.

5. The DC-AC inverter according to claim 2, characterized in that, The full-bridge inverter circuit includes: A first optocoupler, wherein the first pin and the second pin of the first optocoupler are respectively connected to the twelfth pin of the main control chip through the tenth resistor and the eleventh resistor; The second optocoupler has its first and second pins connected to the thirteenth pin of the main control chip via the twelfth and thirteenth resistors, respectively. The base of the second transistor is connected to the third pin of the first optocoupler through the fourteenth resistor, and the emitter and base of the second transistor are connected in series with the fifteenth resistor. The base of the third transistor is connected to the third pin of the second optocoupler through the sixteenth resistor, and the emitter and base of the third transistor are connected in series with the seventeenth resistor. A current inverter bridge is provided, wherein the first terminal of the current inverter bridge is connected to the collector of the second transistor through the eighteenth resistor, the midpoint of the first bridge arm of the current inverter bridge is connected to one end of the third capacitor and the cathode of the fifth diode, the anode of the fifth diode is connected to the first terminal of the current inverter bridge, the other end of the third capacitor is connected to one end of the nineteenth resistor and the anode of the sixth diode, the other end of the nineteenth resistor is connected to the collector of the second transistor, and the cathode of the sixth diode is connected to the inverter power supply. The second terminal of the current inverter bridge is connected to one end of the twentieth resistor and the cathode of the seventh diode, and the other end of the twentieth resistor and the anode of the seventh diode are connected to the third terminal of the first optocoupler. The third terminal of the current inverter bridge is connected to the collector of the third transistor through the twenty-first resistor. The midpoint of the second arm of the current inverter bridge is connected to one end of the fourth capacitor and the cathode of the eighth diode. The anode of the eighth diode is connected to the third terminal of the current inverter bridge. The other end of the fourth capacitor is connected to one end of the twenty-second resistor and the anode of the fourteenth diode. The other end of the twenty-second resistor is connected to the collector of the third transistor. The cathode of the fourteenth diode is connected to the inverter power supply. The fourth terminal of the current inverter bridge is connected to one end of the twenty-third resistor and the cathode of the ninth diode, and the other end of the twenty-third resistor and the anode of the ninth diode are connected to the third terminal of the second optocoupler. The current input terminal of the current inverter bridge is connected to the current output terminal of the switching power supply circuit. The midpoint of the first bridge arm and the midpoint of the second bridge arm of the current inverter serve as the external output terminals of the inverter power supply circuit.

6. The DC-AC inverter according to claim 5, characterized in that, The current inverter bridge includes: The fourth MOS transistor, the gate of which is connected to the collector of the second transistor through the eighteenth resistor; The fifth MOS transistor, the gate of which is connected to one end of the twentieth resistor; The sixth MOS transistor, the gate of which is connected to the collector of the third transistor through the twenty-first resistor; The seventh MOS transistor, the gate of which is connected to one end of the twenty-third resistor; The drain of the fourth MOS transistor and the drain of the sixth MOS transistor are connected to the current output terminal of the switching power supply circuit. The connection point between the source of the fourth MOS transistor and the drain of the fifth MOS transistor serves as the midpoint of the first arm of the current inverter bridge, and the connection point between the source of the sixth MOS transistor and the drain of the seventh MOS transistor serves as the midpoint of the second arm of the current inverter bridge.

7. The DC-AC inverter according to claim 3, characterized in that, The inverter power supply circuit also includes an overcurrent detection circuit, comprising: The 24th resistor has one end connected to the source of the first MOSFET, and the other end connected to one end of the 25th resistor and one end of the 26th resistor. The other end of the 25th resistor is connected to the overcurrent power supply. An operational amplifier, wherein the non-inverting input terminal of the operational amplifier is connected to one end of the 26th resistor and one end of the 6th capacitor, the other end of the 6th capacitor is grounded, the inverting input terminal of the operational amplifier is connected to one end of the 27th resistor, one end of the 28th resistor and the other end of the 7th capacitor, and the output terminal of the operational amplifier is connected to the other end of the 28th resistor, the other end of the 7th capacitor, one end of the 29th resistor and one end of the 30th resistor, the other end of the 27th resistor is grounded, and the other end of the 30th resistor is grounded; The other end of the 29th resistor is connected to the overcurrent detection pin of the main control chip.

8. The DC-AC inverter according to claim 3, characterized in that, The USB power supply circuit includes: The USB driver chip has its first pin connected to one end of the fiftieth resistor, one end of the thirty-first resistor, and one end of the eighth capacitor. The other end of the thirty-first resistor is connected to one end of the ninth capacitor and one end of the tenth capacitor. The fifth pin of the USB driver chip is connected to the other end of the eighth capacitor, the other end of the fiftieth resistor, the other end of the ninth capacitor, and the other end of the tenth capacitor; The Type-C interface has its 12th, 13th, 14th, 15th and 16th pins connected, and also connected to the 5th pin of the USB driver chip, one end of the 11th capacitor, one end of the 12th capacitor, the cathode of the first transient voltage suppression diode, the cathode of the second transient voltage suppression diode and the 1st pin of the Type-C interface; The other end of the eleventh capacitor is connected to the anode of the first transient voltage suppression diode and the fourth pin of the Type-C interface. The other end of the eleventh capacitor is also connected to the first pin of the Type-C interface through the thirty-second resistor. The other end of the twelfth capacitor is connected to the anode of the second transient voltage suppression diode and the tenth pin of the Type-C interface. The other end of the twelfth capacitor is also connected to the first pin of the Type-C interface through the thirty-third resistor. The second and eleventh pins of the Type-C interface are connected to the third pin of the USB driver chip, and also to one end of the thirty-fourth resistor. The other end of the thirty-fourth resistor is connected to the eighth pin of the USB driver chip. The USB interface has a thirteenth capacitor connected in series between its first and fourth pins. The first pin of the USB interface is also connected to the fourth pin of the USB driver chip and one end of the thirty-fifth resistor. The other end of the thirty-fifth resistor is connected to the second pin of the USB driver chip. The sixth pin of the USB driver chip is connected to the first pin of the common mode inductor and one end of the thirteenth, fourteenth, and fifteenth capacitors; the fifth pin of the USB driver chip is connected to the second pin of the common mode inductor and the other end of the thirteenth, fourteenth, and fifteenth capacitors. A sixteenth capacitor is connected in series between the third and fourth pins of the common-mode inductor. The third pin of the common-mode inductor is connected to the source of the eighth MOS transistor. The fourth pin of the common-mode inductor is connected to the USB overcurrent detection circuit. The detection output of the USB overcurrent detection circuit is connected to the sixteenth pin of the main control chip. A 36th resistor is connected in series between the gate and drain of the eighth MOS transistor. The drain of the eighth MOS transistor is connected to the source of the third MOS transistor. The gate of the eighth MOS transistor is connected to one end of a 37th resistor. The other end of the 37th resistor is connected to the collector of the fourth transistor. A 38th resistor is connected in series between the emitter and base of the fourth transistor and grounded. The base of the fourth transistor is also connected to the 15th pin of the main control chip through a 39th resistor.

9. The DC-AC inverter according to claim 1, characterized in that, It also includes the main control chip startup circuit, including: A start button is provided. The first end of the start button is connected to the power supply terminal of the lithium battery pack. The other end of the start button is connected to the cathode of the tenth diode and one end of the fortieth resistor. The other end of the fortieth resistor is connected to one end of the forty-first resistor, one end of the seventeenth capacitor, and the fifth pin of the main control chip. The other end of the forty-first resistor and the other end of the seventeenth capacitor are grounded. The startup chip has its second pin connected to the anode of the tenth diode via a forty-second resistor. The second pin is also connected to the first pin of the startup chip and grounded via a seventeenth capacitor. The third pin is connected to one end of the eighteenth and nineteenth capacitors, with the other ends of the eighteenth and nineteenth capacitors grounded. The third pin is also connected to the twentieth pin of the main control chip, and further connected to the fourth pin of the main control chip via a forty-third resistor.

10. The DC-AC inverter according to claim 9, characterized in that, The LED lighting circuit includes: An LED start button is provided, with one end connected to the power supply terminal of the lithium battery pack, and the other end connected to one end of the forty-fourth resistor and the cathode of the twelfth diode. The other end of the forty-fourth resistor is connected to one end of the forty-fifth resistor and one end of the twentieth capacitor. The other end of the forty-fifth resistor and the other end of the twentieth capacitor are grounded, and the other end of the forty-fourth resistor is also connected to the eleventh pin of the main control chip. The anode of the twelfth diode is also connected to the anode of the thirteenth diode and one end of the forty-second resistor, and the cathode of the thirteenth diode is connected to the power input terminal of the USB circuit. The first LED and the second LED have their cathodes connected to the LED power supply. The anodes of the first LED and the second LED are connected to the drain of the ninth MOS transistor through resistors forty-six and forty-seven, respectively. A resistor forty-eight is connected in series between the source and the gate of the ninth MOS transistor and grounded. The gate of the ninth MOS transistor is connected to the LED start-up terminal of the main control chip through resistor forty-nine.

Images