A DC-DC converter adapting to ultra-wide input voltage range

Abstract

The present invention discloses a DC-DC converter adaptable to ultra-wide input voltage, including: a controller for energy conversion; a startup enabling circuit, including a voltage-dividing network and a first optocoupler, the voltage-dividing network is connected to the high-voltage signal input terminal, the voltage-dividing network is also connected to the secondary side of the first optocoupler, the primary side of the first optocoupler is connected to an RC network filter network, and the RC network filter network is connected to a startup enabling signal; a shutdown enabling circuit, including a second optocoupler, an NPN-type transistor and an auxiliary winding, the shutdown enabling signal is connected to the primary side of the second optocoupler, the secondary side of the second optocoupler is connected to the NPN-type transistor and the auxiliary winding, and the shutdown of the converter is controlled by controlling the conduction and cutoff of the NPN-type transistor. It is particularly suitable for DC-DC converters with a power level of 100W. Through the innovative startup enabling circuit and shutdown enabling circuit design, reliable startup, shutdown and self-maintenance of ultra-wide input voltage are achieved, and it has an overvoltage protection function.

Description

Technical Field

[0001] The invention belongs to the technical field of DC-DC converters, and the invention relates to a DC-DC converter adapting to an ultra-wide range of input voltages. Background Art

[0002] With the continuous advancement of electronic equipment and the expansion of application fields, the power supply system is the core part of electronic equipment, and its performance and reliability have a vital impact on the entire system. Among many power supply systems, DC-DC converters are widely used in various demand occasions, such as industrial automation, electric vehicles, and communication base stations, due to their high efficiency, low noise, small size, and good dynamic response characteristics. However, with the development of power electronics technology, traditional DC-DC converters face many challenges in the application scenarios of adjusting ultra-wide input voltage, overvoltage protection, low-cost external control switch enable, and providing high drive voltage. The specific shortcomings are as follows:

[0003] 1. Ultra-wide range input voltage regulation capability: Traditional DC-DC converters mainly achieve power conversion through basic topologies such as buck, boost, buck-boost, etc. They are usually designed for a specific input voltage range and are difficult to adapt to a wide range of input voltage changes. This limitation is particularly evident in areas such as industrial and automotive electronics where input voltages fluctuate greatly;

[0004] 2. Overvoltage protection mechanism: Although some converters have basic overvoltage protection functions, these protection mechanisms are often not flexible enough or have slow response speeds, and cannot effectively prevent damage to the system caused by voltage mutations. This limits their use in high-reliability applications that require fast response;

[0005] 3. External control on / off enable: In the prior art, the on / off control of the converter often requires additional hardware support, which not only increases the overall complexity of the system, but also increases the cost, which is not conducive to achieving a low-cost and high-reliability power supply system;

[0006] 4. High drive voltage capability: For high-power applications that require driving SiC (silicon carbide) type switches, existing drive solutions often cannot provide sufficiently high drive voltages and require special designs, which limits their application in high-performance power electronic equipment.

[0007] 5. Cost issue: The manufacturing and maintenance costs of high power density converters are relatively high, which limits their promotion in some cost-sensitive application fields. Especially in situations where large-scale deployment is required, cost-effectiveness is an important consideration;

[0008] UCC28740 is an ultra-low standby power flyback control chip for automotive applications with integrated high voltage startup and optocoupler feedback. Figure 1 As shown in the figure, the chip integrates a startup switch with a withstand voltage rating of 700V, supports optocoupler output regulation, and can operate in discontinuous mode (DCM) with valley switching, thereby reducing switching losses. In addition, UCC28740 also has overvoltage, low voltage and overcurrent protection functions, which are implemented through independent voltage detection VS, current detection CS and feedback FB pins. Although UCC28740 offers many advantages, there are still some challenges in designing flyback converters, especially in ultra-wide input voltage scenarios. For example, traditional designs may not be able to achieve reliable self-starting and self-maintenance within an ultra-wide input voltage range, and there are also certain limitations in overvoltage protection. Summary of the invention

[0009] The purpose of the present invention is to provide a DC-DC converter that is adaptable to an ultra-wide range of input voltages, and is particularly suitable for DC-DC converters with a power level of 100W. Through innovative designs of a startup enabling circuit and a shutdown enabling circuit, the present invention achieves reliable startup, shutdown, and self-maintenance for an ultra-wide range of input voltages, and has an effective overvoltage protection function.

[0010] The technical solution to achieve the purpose of the present invention is:

[0011] A DC-DC converter adapted to an ultra-wide range of input voltages, comprising:

[0012] Controllers for energy conversion;

[0013] A power-on enabling circuit, comprising a voltage-dividing network and a first optocoupler, wherein the voltage-dividing network is connected to a high-voltage signal input terminal, the voltage-dividing network is also connected to a secondary side of the first optocoupler, the primary side of the first optocoupler is connected to an RC network filter network, and the RC network filter network is connected to a power-on enabling signal;

[0014] The shutdown enabling circuit includes a second optocoupler, an NPN transistor and an auxiliary winding. The shutdown enabling signal is connected to the primary side of the second optocoupler, and the secondary side of the second optocoupler is connected to the NPN transistor and the auxiliary winding. The shutdown of the converter is controlled by controlling the conduction and cutoff of the NPN transistor.

[0015] In the preferred technical solution, a first voltage zener diode is also arranged between the voltage divider network and the secondary side of the first optocoupler, the anode of the first voltage zener diode is connected to the secondary side grounding point GNDp, the cathode is connected to the voltage divider network, and is also connected to the collector of the secondary side transistor of the first optocoupler, the emitter of the secondary side transistor of the first optocoupler is connected to the HV end of the controller, and the first voltage zener diode is connected in parallel with a first capacitor.

[0016] In the preferred technical solution, the shutdown enable signal is connected to the base of the PNP transistor through the first resistor, the emitter of the PNP transistor is connected to the +5V auxiliary power supply, the second resistor is connected between the base and the emitter of the PNP transistor, and the collector of the PNP transistor is connected to the primary ground point GNDs through the third resistor, the fourth resistor and the second capacitor;

[0017] The emitter of the secondary transistor of the second optocoupler is connected to the non-same-name end of the auxiliary winding, and is connected to the secondary grounding point GNDp together. The same-name end of the auxiliary winding forms an RC low-pass filter network through the fifth resistor, the sixth resistor, the third capacitor, and the fourth capacitor. The voltage is transmitted to the collector of the NPN transistor and then to the emitter through the RC low-pass filter network, and finally delivered to the VDD pin of the controller. At the collector and emitter of the NPN transistor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor are respectively connected in parallel to the ground.

[0018] In a preferred technical solution, the base of the NPN transistor is connected to the cathode of the second voltage zener diode, and the anode of the second voltage zener diode is grounded to GNDp.

[0019] In the preferred technical solution, an anti-reverse bias diode is arranged between the RC low-pass filter network and the collector of the NPN transistor, and an RC absorption circuit is connected in parallel at both ends of the anti-reverse bias diode, including a seventh resistor and a seventh capacitor.

[0020] In the preferred technical solution, an eighth resistor and a ninth resistor are connected in series in parallel to the ground at the collector of the NPN transistor, the connection point between the base of the NPN transistor and the cathode of the second voltage zener diode is connected to the connection point of the eighth resistor and the ninth resistor, and the connection point of the eighth resistor and the ninth resistor is connected to the collector of the secondary transistor of the second optocoupler.

[0021] In a preferred technical solution, the VS end of the controller is connected to an auxiliary winding detection circuit, and the auxiliary winding detection circuit is used to detect the voltage across the auxiliary winding, and to perform primary side regulation according to the voltage information of the auxiliary winding to achieve constant current control of the output current.

[0022] In the preferred technical solution, the FB end of the controller is connected to an output optocoupler feedback circuit, which includes an optocoupler device. The output voltage of the primary side of the optocoupler device is detected, and the voltage signal is converted into a feedback signal and transmitted to the controller of the secondary side of the optocoupler device.

[0023] In the preferred technical solution, the high-voltage signal input end is also connected to a peak absorption circuit, which includes a plurality of resistors connected in series and an eighth capacitor connected in parallel with the plurality of resistors connected in series, and one end of the plurality of resistors connected in series to the eighth capacitor is connected to a diode.

[0024] In the preferred technical solution, the DRV terminal of the controller is connected to the drive circuit, and the drive circuit provides a switching signal for the switching device. The CS terminal of the controller is connected to the primary current detection circuit, and the primary current detection circuit converts the detected current signal into a voltage signal and feeds it back to the controller. The primary current detection circuit and the controller realize current closed-loop control.

[0025] Compared with the prior art, the present invention has the following significant advantages:

[0026] 1. Functional decoupling:

[0027] The power-on and power-off functions in the present invention are independent of each other and are controlled by independent external given signals, thus achieving the decoupling of the power-on and power-off functions. This design improves the flexibility and reliability of the system.

[0028] 2. Low-cost solution:

[0029] By appropriately adding additional components such as resistors and capacitors, transistors and voltage-stabilizing diodes, the present invention provides a low-cost solution suitable for a wide range of application scenarios;

[0030] 3. Adaptability to ultra-wide input voltage range:

[0031] The startup circuit of the present invention achieves effective adaptation to ultra-wide input voltages through carefully selected resistors, capacitors and voltage regulator diodes. This design ensures stable operation of the circuit under different input voltage conditions, thereby improving the reliability of the system. Similarly, the shutdown circuit achieves wide adaptability to the auxiliary winding voltage through appropriate selection of resistors, capacitors and voltage regulator diodes, which not only ensures stable operation of the circuit under different auxiliary winding voltage conditions, but also increases the robustness of the system in the face of voltage fluctuations;

[0032] 4. Overvoltage protection capability:

[0033] When the input voltage exceeds the specified range, the design of voltage-regulating diode and series resistor voltage divider not only protects the controller chip, but also ensures the safe operation of the system;

[0034] 5. Stability of auxiliary winding voltage:

[0035] The shutdown circuit design uses a voltage-stabilizing diode and a series resistor to divide the voltage, making the auxiliary winding voltage relatively stable under an ultra-wide input voltage range, further enhancing the stability of the system.

[0036] 6. Self-sustaining capability of the controller:

[0037] When the main power and start-up signals are given, the controller can achieve self-maintenance, reducing the need for external control and improving the automation of the system;

[0038] 7. SiC switching devices adapted for high voltage drive:

[0039] The controller's higher driving voltage makes it particularly suitable for SiC switching devices that require high-voltage drive, further reducing system losses and improving overall efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the pinout diagram of the UCC28740 controller;

[0041] Figure 2 To adapt to the DC-DC converter circuit topology of ultra-wide input voltage range;

[0042] Figure 3 This is the electrical connection diagram of the power-on enabling circuit;

[0043] Figure 4 This is the electrical connection diagram of the shutdown enable circuit. DETAILED DESCRIPTION

[0044] The principle of the present invention is to provide a flyback converter design based on the UCC28740 controller. The solution is particularly suitable for 100W power-level DC-DC converters. Through innovative startup and shutdown enabling circuit design, the present invention achieves reliable startup, shutdown and self-maintenance for ultra-wide input voltage range, and has effective overvoltage protection function. Example

[0045] like Figure 2 As shown, a DC-DC converter adapted to an ultra-wide range of input voltage comprises:

[0046] Controllers for energy conversion;

[0047] A power-on enabling circuit, comprising a voltage-dividing network and a first optocoupler, wherein the voltage-dividing network is connected to a high-voltage signal input terminal, the voltage-dividing network is also connected to a secondary side of the first optocoupler, the primary side of the first optocoupler is connected to an RC network filter network, and the RC network filter network is connected to a power-on enabling signal;

[0048] The shutdown enabling circuit includes a second optocoupler, an NPN transistor and an auxiliary winding. The shutdown enabling signal is connected to the primary side of the second optocoupler, and the secondary side of the second optocoupler is connected to the NPN transistor and the auxiliary winding. The shutdown of the converter is controlled by controlling the conduction and cutoff of the NPN transistor.

[0049] In the preferred technical solution, a first voltage zener diode is also arranged between the voltage divider network and the secondary side of the first optocoupler, the anode of the first voltage zener diode is connected to the secondary side grounding point GNDp, the cathode is connected to the voltage divider network, and is also connected to the collector of the secondary side transistor of the first optocoupler, the emitter of the secondary side transistor of the first optocoupler is connected to the HV end of the controller, and the first voltage zener diode is connected in parallel with a first capacitor.

[0050] Specifically, the controller is UCC28740, including VDD, DRV, HV, GND, VS, CS and feedback FB pins.

[0051] The startup enable circuit on the startup side includes dividing the voltage (200-1000V) from the high-voltage DC bus through multiple large resistors in series, and supplying it to the Zener diode for voltage stabilization. The externally given startup signal is transmitted to the low-voltage side through optocoupler isolation, thereby controlling the conduction of the secondary high-voltage side of the optocoupler. After the optocoupler is turned on, the energy at the Zener diode end is transmitted to the controller to start the device.

[0052] The shutdown enable circuit on the shutdown side controls the optocoupler enable through the shutdown signal sent externally. When the optocoupler is turned on, the current inside the optocoupler flows, which makes the resistor connected in parallel with the secondary side of the optocoupler almost short-circuited, thereby lowering the voltage across the resistor. This will cause the base voltage of the NPN transistor to be approximately zero, causing the transistor to be cut off. The path that supplies power to the controller VDD pin through the auxiliary winding is cut off, and the controller is powered off and disabled, thereby achieving the effect of shutting down the device.

[0053] like Figure 2 The DC-DC converter system not only includes the power conversion path, but also covers key functional modules that are essential for achieving accurate power management.

[0054] Power-on enable circuit: This circuit is responsible for receiving and responding to external power-on enable signals. Once a valid power-on signal is received, the circuit will trigger the startup process of the DC-DC converter to ensure that the system can respond to changes in power demand in a timely manner.

[0055] Shutdown enable circuit: Corresponding to the power-on enable circuit, the shutdown enable circuit will execute the shutdown process of the DC-DC converter when receiving the external shutdown enable signal, which not only ensures the stability of the system, but also prolongs the service life of the power supply components.

[0056] Output optocoupler feedback circuit: This circuit uses optocoupler devices to achieve electrical isolation between the primary high voltage input and the secondary output. By accurately detecting the output voltage on the secondary side and converting the voltage signal into a feedback signal and transmitting it to the primary controller, the stability and accuracy of the output voltage are ensured, thereby improving the transient response to large load steps.

[0057] Primary current detection circuit: This circuit is responsible for real-time monitoring of primary current changes. By converting the detected current signal into a voltage signal and feeding it back to the controller, the current detection circuit works together with the controller to achieve current closed-loop control, thereby ensuring the constant current output characteristics of the system.

[0058] Auxiliary winding detection circuit: This circuit is responsible for detecting the voltage across the auxiliary winding, which is usually proportional to the secondary output voltage of the transformer. The primary side is regulated by the voltage information of the auxiliary winding to achieve constant current control of the output current.

[0059] Spike absorption circuit: The main function is to reduce the voltage spikes caused by leakage inductance, which may damage the switching device when the switch tube is turned off.

[0060] Driver circuit: Provides appropriate switching signals to switching devices (such as MOSFET).

[0061] Specifically, a specific embodiment of the power-on enabling circuit is as follows:

[0062] like Figure 2 and Figure 3 As shown in FIG. 1 , the power-on enable circuit is mainly composed of an optocoupler OP201, a high-level valid external given power-on enable signal and related passive components, including resistors R230, R228, R233, capacitor C213 and diode D204 connected to the primary side of the optocoupler OP201, and resistors R204, R205, R206, R207, R202, R201, capacitor C203 and Zener diode Z200 connected to the high-voltage end of the secondary side of the optocoupler OP201. By using the optocoupler device OP201, this design realizes electrical isolation between the primary side and the secondary side, ensuring the safety and reliability of the system. In this isolation strategy, the primary side of the optocoupler uses GNDs as its ground reference, while the secondary side of the optocoupler uses GNDp as its ground reference.

[0063] In this design, six resistors, R201, R202, R207, R206, R205 and R204, are connected in series to achieve effective voltage division for the ultra-wide range of 200-1000V high voltage input. The voltage signal after voltage division is first stabilized and filtered by capacitor C203 to eliminate possible voltage fluctuations and noise; then the stabilized voltage signal is supplied to the voltage stabilizing diode Z200 to further stabilize the voltage level and prevent voltage mutations from damaging the circuit.

[0064] The anode (A pole) of the Zener diode Z200 is connected to the secondary ground point GNDp, and its cathode (K pole) is connected to the aforementioned series resistor network, and is also connected to the collector (c pole) of the secondary transistor of the optocoupler device OP201. The emitter (e pole) of the secondary transistor of the optocoupler is connected to the HV end of the controller.

[0065] The power-on enable signal first passes through the RC network filter network composed of resistors R233, R228, R230 and capacitor C213, thereby providing a stable signal to the anode (A pole) of the primary light-emitting diode of the optocoupler OP201, and the cathode (K pole) of the light-emitting diode is connected to the secondary ground point GNDs. In order to prevent potential current backflow, a diode D204 is added to the transmission path of the enable signal, and the A pole of the diode is connected to the signal input terminal.

[0066] In this DC-DC converter system, the power-on enable signal plays a vital role. This signal is an externally given high voltage valid signal. When the system is not working, it remains in a stable low level state to ensure that the system is in standby mode. When the need to start the DC-DC converter appears, the power-on enable signal will switch from a low level to a high level state. This transition triggers the primary side light-emitting diode of the optocoupler OP201 to emit light, which in turn causes its secondary side transistor to turn on. Subsequently, the 200-1000V high voltage signal from the input end is stabilized by the resistor divider network and the voltage regulator diode Z200. The processed signal is then safely transmitted to the HV pin of the controller to charge the controller's start-up capacitor, thereby triggering and completing the system startup process. Once the controller is successfully started and running, the startup circuit inside the controller will automatically exit the working state. At this time, the external power-on enable signal will also turn to a low level, and the system will enter the normal working mode and be ready to wait for the next startup command. Through the startup mechanism of this design, a robust startup strategy is provided for the DC-DC converter, ensuring the high performance and long life operation of the system.

[0067] Specifically, a specific embodiment of the shutdown enabling circuit is as follows:

[0068] like Figure 2 and Figure 4 As shown, the shutdown enable circuit of the DC-DC converter includes an optocoupler OP202, an externally given low-level effective shutdown enable signal, an NPN transistor Q201, a PNP transistor Q202, a voltage-stabilizing diode Z202, a diode D203, an auxiliary winding T200C and other related passive components. The circuit achieves electrical isolation between the primary side and the secondary side through the optocoupler OP202, wherein the primary side of the optocoupler uses GNDs as a reference ground, and the secondary side uses GNDp as a reference ground.

[0069] On the primary side of the optocoupler OP202, the emitter (e-pole) of the PNP transistor Q202 is connected to the +5V auxiliary power supply. Resistor R234 is connected between the base (b-pole) and emitter (e-pole) of Q202, and the shutdown enable signal is connected to the base (b-pole) of Q202 through resistor R235. The collector (c-pole) of Q202 is connected to the ground point GNDs of the primary side through resistors R229, R231 and capacitor C212.

[0070] For the secondary side of the optocoupler OP202, the emitter (e pole) of the secondary transistor of the optocoupler is connected to the non-same-name end of the auxiliary winding T200C, and connected to the ground point GNDp of the secondary side. The same-name end of the auxiliary winding T200C transmits the voltage to the collector (c pole) of the NPN transistor Q201 and then to the emitter (e pole) through the RC low-pass filter network composed of resistors R226, R225 and capacitors C211, C210, and finally to the VDD pin of the controller. The VDD pin ensures the normal working voltage supply of the controller. The base (b pole) of Q201 is connected to the cathode (K pole) of the Zener diode Z202, and the anode (A pole) of the Zener diode Z202 is grounded to GNDp. To prevent energy from flowing back, an anti-reverse bias diode D203 and its parallel RC absorption circuit, including resistor R236 and capacitor C236, are also added in this transmission path. At the collector (c-pole) and emitter (e-pole) of the transistor Q201, capacitors C211, C210 and capacitors C209, C206 are connected in parallel to the ground GNDp respectively to stabilize the voltage.

[0071] When the DC-DC converter is in normal working state, the shutdown enable signal remains at a high level, causing the PNP transistor Q202 to be in the cut-off state, and the optocoupler OP202 is not triggered to work. At this time, the voltage generated by the auxiliary winding T200C, after being processed by the diode D203 to prevent current backflow and the RC filter network, passes through the series resistors R227 and R232. The midpoint of the resistors R227 and R232 is connected to the collector of the secondary transistor of the optocoupler OP202, providing a stable power supply for the voltage regulator diode Z202. This causes the base (pole b) potential of the NPN transistor Q201 to rise, making it conductive, thereby allowing the voltage of the auxiliary winding to reach the VDD pin of the controller, ensuring the normal operation of the controller.

[0072] When the system receives a shutdown command, the external shutdown enable signal switches from a high level to a low level, and this change turns on the PNP transistor Q202. Subsequently, the +5V voltage provided by the auxiliary power supply is divided by the resistor network R229 and R231, thereby driving the optocoupler OP202 to turn on its secondary transistor. This process effectively short-circuits the voltage-stabilizing diode Z202 and its parallel resistor R232 to ground, causing the base (pole b) potential of the NPN transistor Q201 to drop to 0, causing the transistor to be cut off. Therefore, the power supply path from the auxiliary winding to the controller is cut off, and the controller loses power and stops working, achieving a safe shutdown of the DC-DC converter. After the system is shut down, the external shutdown signal can be restored to a high level to reset the system in preparation for the next shutdown requirement. This design ensures that the DC-DC converter can respond to external commands and achieve accurate power management, while ensuring the stability and reliability of the system.

[0073] Self-sustaining capability after startup:

[0074] The DC-DC flyback converter of the present invention is designed to have the ability to self-maintain after startup. Once the device is started, the voltage across the auxiliary winding T200C will be divided by the series resistor network R227 and R232. Subsequently, the voltage generated across the resistor R232 will be stabilized by the voltage stabilizing diode Z202. Since the cathode (K pole) of the voltage stabilizing diode Z202 is directly connected to the base (b pole) of the NPN transistor Q201, this ensures that a relatively stable potential can always be maintained at the base of the transistor. Therefore, the transistor Q201 can always remain in the on state, providing and maintaining a stable power supply voltage for the VDD power supply pin of the controller. This design ensures that the controller can continue to operate normally until an external shutdown signal is received. This not only significantly improves the stability and reliability of the system, but also enhances the performance and life of the entire converter through precise power management.

[0075] Ultra-wide range regulation capability compatible with 1000V input:

[0076] In the design of the flyback converter of the present invention, through the carefully configured input series resistors R201, R202, R204, R205, R206 and R207, combined with the voltage stabilizing diode Z200, compatibility with high-voltage main power input up to 1000V is achieved. Although the HV pin of the controller only has a voltage level withstand capability of 700V, this design achieves compatibility with 1000V input voltage through the synergistic effect of the resistor voltage divider and the voltage stabilizing diode, and reasonable parameter selection. This design not only effectively protects the circuit from damage caused by excessive voltage, but also ensures the ability to accurately adjust the voltage under an ultra-wide range of input voltages. Through the optimized circuit configuration, the system not only improves the adaptability to different input voltage conditions, but also demonstrates excellent stability and reliability under various voltage environments, significantly improving the performance of the converter, so that it can meet a wider range of application needs.

[0077] Adapt to the driving voltage of SiC switch tube:

[0078] In the present invention, the stable working voltage of the voltage stabilizing diode Z202 comes from the voltage division after the auxiliary winding T200C supplies power to the series resistor network, and the voltage division function is jointly completed by the resistors R227 and R232. Since the voltage stabilizing diode Z202 is connected in parallel with the resistor R232, its voltage stabilizing characteristic ensures that the voltage stabilizing diode starts to work normally and exerts its voltage stabilizing function only when the voltage across the auxiliary winding exceeds a specific threshold. This process triggers the conduction of the NPN transistor Q201, providing a stable power supply for the VDD pin of the controller.

[0079] This design cleverly utilizes the voltage stabilization function of the voltage regulator Z202 to ensure that the VDD pin of the controller can continuously maintain a relatively high power supply voltage level. This mechanism effectively prevents the controller output drive voltage from dropping due to insufficient VDD voltage, and avoids the problems of insufficient opening of the SiC switch tube and high loss caused by this. By maintaining a higher drive voltage, the present invention not only improves the conduction efficiency of the SiC switch tube, but also reduces the overall loss of the system, thereby significantly improving the overall efficiency and performance of the system.

[0080] Overvoltage protection capability:

[0081] In the design of the DC-DC flyback converter of the present invention, an enhanced overvoltage protection mechanism is realized by introducing the configuration of the voltage regulator diodes Z202 and Z200. The function of the voltage regulator diode Z202 is to limit the voltage across the auxiliary winding to prevent it from being too high when the input voltage fluctuates greatly, thereby effectively protecting the VDD pin of the controller from overvoltage damage. This measure ensures the stability and safety of the controller when facing input voltage fluctuations.

[0082] At the same time, the voltage stabilizing diode Z200 plays a role when the input high voltage fluctuates greatly, and protects the HV pin of the controller through its voltage stabilizing characteristics to avoid damage to the controller due to high voltage fluctuations. This design not only improves the system's resistance to abnormal voltage fluctuations, but also enhances the durability and reliability of the entire converter. In summary, the dual voltage stabilizing protection mechanism of the present invention significantly improves the safety and reliability of the system by setting voltage stabilizing diodes at key nodes.

[0083] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A DC-DC converter adapted to an ultra-wide range of input voltages, characterized in that: include: Controllers for energy conversion; A power-on enabling circuit, comprising a voltage-dividing network and a first optocoupler, wherein the voltage-dividing network is connected to a high-voltage signal input terminal, the high-voltage signal input terminal is the voltage of a high-voltage side DC bus, the voltage-dividing network is also connected to a secondary side of the first optocoupler, the primary side of the first optocoupler is connected to an RC network filter network, and the RC network filter network is connected to a power-on enabling signal; a first voltage-stabilizing diode is also provided between the voltage-dividing network and the secondary side of the first optocoupler, the anode of the first voltage-stabilizing diode is connected to a secondary side grounding point GNDp, the cathode thereof is connected to the voltage-dividing network, and is also connected to the collector of a secondary side transistor of the first optocoupler, the emitter of the secondary side transistor of the first optocoupler is connected to the HV terminal of the controller, and the first voltage-stabilizing diode is connected in parallel with a first capacitor; A shutdown enabling circuit comprises a second optocoupler, an NPN-type transistor and an auxiliary winding, wherein a shutdown enabling signal is connected to the primary side of the second optocoupler, a secondary side of the second optocoupler is connected to the NPN-type transistor and the auxiliary winding, and the shutdown of the converter is controlled by controlling the conduction and cutoff of the NPN-type transistor; the shutdown enabling signal is connected to the base of the PNP-type transistor through a first resistor, the emitter of the PNP-type transistor is connected to a +5V auxiliary power supply, a second resistor is connected across the base and the emitter of the PNP-type transistor, and the collector of the PNP-type transistor is connected to the primary ground point GNDs through a third resistor, a fourth resistor and a second capacitor; The emitter of the secondary transistor of the second optocoupler is connected to the non-same-name end of the auxiliary winding, and is connected to the secondary ground point GNDp together. The same-name end of the auxiliary winding forms an RC low-pass filter network through the fifth resistor, the sixth resistor, the third capacitor, and the fourth capacitor. The voltage is transmitted to the collector of the NPN transistor and then to the emitter through the RC low-pass filter network, and finally delivered to the VDD pin of the controller. At the collector and emitter of the NPN transistor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor are connected in parallel to the ground respectively; The base of the NPN transistor is connected to the cathode of the second voltage stabilizing diode, and the anode of the second voltage stabilizing diode is grounded to GNDp; An eighth resistor and a ninth resistor are connected in series to the ground in parallel at the collector of the NPN transistor, the connection point between the base of the NPN transistor and the cathode of the second voltage-stabilizing diode is connected to the connection point of the eighth resistor and the ninth resistor, and the connection point of the eighth resistor and the ninth resistor is connected to the collector of the secondary transistor of the second optocoupler.

2. The DC-DC converter adapted to ultra-wide input voltage range according to claim 1, characterized in that: An anti-reverse bias diode is arranged between the RC low-pass filter network and the collector of the NPN transistor, and an RC absorption circuit is connected in parallel at both ends of the anti-reverse bias diode, including a seventh resistor and a seventh capacitor.

3. The DC-DC converter adapted to ultra-wide input voltage range according to claim 1, characterized in that: The VS terminal of the controller is connected to an auxiliary winding detection circuit, and the auxiliary winding detection circuit is used to detect the voltage across the auxiliary winding, and to perform primary-side regulation according to the voltage information of the auxiliary winding to achieve output current constant current control.

4. The DC-DC converter adapting to ultra-wide input voltage range according to claim 1, characterized in that: The FB terminal of the controller is connected to an output optocoupler feedback circuit, which includes an optocoupler device, and detects the output voltage of the primary side of the optocoupler device and converts the voltage signal into a feedback signal to be transmitted to the controller of the secondary side of the optocoupler device.

5. The DC-DC converter adapting to ultra-wide input voltage range according to claim 1, characterized in that: The high-voltage signal input end is also connected to a peak absorption circuit, which includes a plurality of resistors connected in series and an eighth capacitor connected in parallel with the plurality of resistors connected in series, and one end of the plurality of resistors connected in series to the eighth capacitor is connected to a diode.

6. The DC-DC converter adapting to ultra-wide input voltage range according to claim 1, characterized in that: The DRV terminal of the controller is connected to a drive circuit, which provides a switch signal for the switch device. The CS terminal of the controller is connected to a primary current detection circuit, which converts the detected current signal into a voltage signal and feeds it back to the controller. The primary current detection circuit and the controller realize current closed-loop control.

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