Modulating multi-level power converter architecture

Abstract

The present disclosure relates to a power converter comprising: a first stage regulated DC-DC converter configured to convert an input DC voltage to an intermediate DC voltage; a second stage open loop DC-DC converter configured to convert the intermediate DC voltage to an output DC voltage or an output DC current to a load; and a controller configured to control the first stage regulated DC-DC converter to regulate the output DC voltage or the output DC current by adjusting the intermediate DC voltage based on a measurement of the output DC voltage or the output DC current and a target output DC voltage or a target output DC current. The present disclosure also relates to a method of converting an input DC voltage to an output DC voltage using a two stage DC-DC power converter architecture.

Description

Technical Field

[0001] This disclosure relates to a multi-stage DC-DC power converter architecture. This disclosure also relates to a method for converting an input DC voltage to an output DC voltage using a multi-stage DC-DC power converter architecture. Background Technology

[0002] In modern electronic systems, especially with the increasing demand for compact, high-performance devices, efficient power conversion is a critical requirement. Power converters, particularly DC-DC converters, are widely used to convert DC input voltages to different DC output voltages, enabling the power supply of various components in the system. Conventional DC-DC converters have long been the cornerstone of power conversion technology. These converters have proven reliable in many applications; however, they often face the challenge of balancing efficiency, size, and thermal management, especially in high power density applications.

[0003] One of the significant drawbacks of traditional DC-DC converter architectures is the inherent trade-off between efficiency, size, and thermal performance. As electronic devices become increasingly compact, the demand for converters with high power density and low power loss is also growing. However, conventional architectures often struggle to achieve this balance, especially under varying input and output conditions. This can lead to increased power losses, higher heat generation, and reduced overall system efficiency, particularly in high-current applications or where space constraints are critical.

[0004] Furthermore, the need for precise voltage regulation under varying operating conditions further increases the complexity of these converter designs and implementations. As systems demand increasingly stringent voltage level regulation, particularly in sensitive applications, conventional power converters may fail to deliver the desired performance without significantly increasing circuit complexity or component size. This necessitates compromises between power delivery reliability and system efficiency, posing a significant challenge to the development of next-generation electronic systems.

[0005] Therefore, the objective of this disclosure is to provide a power conversion architecture that overcomes the limitations of existing DC-DC converters by improving efficiency, reducing component stress, and increasing power density without compromising size or thermal management. This objective is achieved by introducing a DC-DC power converter architecture designed to provide improved overall system performance for a wide variety of applications. Summary of the Invention

[0006] This disclosure relates to a power converter comprising: a first-stage regulated DC-DC converter configured to convert an input DC voltage to an intermediate DC voltage; a second-stage open-loop DC-DC converter configured to convert the intermediate DC voltage to an output DC voltage to a load; and a controller configured to control the first-stage regulated DC-DC converter to regulate the output voltage or output current, thereby also adjusting the intermediate DC voltage based on measurements of the output DC voltage and a target output DC voltage.

[0007] The power converter described in this article offers several technical advantages, particularly in terms of efficiency and power density. By dividing the power conversion process into two stages, system and / or system designers can independently optimize the operation of each stage. The first stage is regulated, allowing precise control over the final output DC voltage or current, and also indirectly controlling the intermediate DC voltage, which has a fixed conversion ratio relative to the final output DC voltage or current. This two-stage approach also reduces stress on the components in the first stage, as the second stage handles the final conversion to the desired output voltage or current. The second stage operates in an open-loop configuration, achieving high efficiency due to its simplified design and optimization for a specific fixed conversion rate.

[0008] This system is particularly advantageous in space-constrained applications requiring high power density. The architecture allows the second stage to be placed closer to the load, reducing losses from long interconnect dependencies and improving overall system performance. Preferably, the second stage can be directly integrated with the load on the same chipset. The modular nature of the second stage, configurable with multiple sub-converters, provides flexibility in achieving various fixed conversion rates, thus offering a universal solution for diverse power conversion needs. The combination of a regulated first stage and a highly efficient second stage results in a power converter that is both compact and capable of providing precise voltage regulation under a wide range of load conditions.

[0009] In some embodiments, the first stage may be a linear regulator, a switch-mode converter such as a switched-capacitor converter or a switched-inductor converter, or a resonant converter, while the second stage may include a switched-capacitor converter or a solid-state transformer. Generally, a switch-mode converter can be understood as a DC-DC converter that uses electronic switching elements (such as transistors or MOSFETs) to efficiently convert electrical energy between different voltage levels. This flexibility in component selection allows the system to be customized to specific application requirements, thus providing a balance between efficiency, size, and cost. The controller's ability to dynamically adjust the intermediate voltage further enhances the system's adaptability to different operating conditions, ensuring that the power converter maintains optimal performance in a wide variety of scenarios.

[0010] This disclosure also relates to a method for converting an input DC voltage into an output DC voltage, the method comprising the steps of: providing a power converter comprising: a first-stage regulated DC-DC converter adapted to receive input DC power and generate an intermediate DC voltage; a second-stage open-loop DC-DC converter adapted to receive the intermediate DC voltage from the first-stage regulated DC-DC converter and generate an output DC voltage; and controlling the first-stage regulated DC-DC converter to adjust the intermediate DC voltage, thereby also adjusting the output DC voltage based on measurements of the output DC voltage and a target output DC voltage.

[0011] This method offers several technical advantages by utilizing a two-stage power conversion architecture. By dividing the conversion process into two distinct stages, the method allows for precise control of the output DC voltage and, indirectly, the intermediate voltage, resulting in optimized performance of the second stage. The ability of the first stage to regulate the intermediate voltage ensures that the second stage operates under optimal conditions, thereby improving the overall efficiency of the power conversion process. This division also allows for the design and optimization of each stage for specific functions, thereby reducing stress on components and improving system reliability.

[0012] This method is particularly effective in applications requiring high efficiency and compact design. By controlling the intermediate voltage, it ensures that the power converter can adapt to different load conditions while maintaining a stable and accurate output. This adaptability is crucial in scenarios with fluctuating input voltage or load demand, enabling the system to dynamically adjust and maintain optimal performance. A modular approach, which may include a second stage with multiple sub-converters, further enhances the system's flexibility, allowing it to efficiently meet diverse power conversion needs.

[0013] In some embodiments, the first stage can be implemented using a linear regulator, a switch-mode converter, or a resonant converter, while the second stage can utilize a switched-capacitor converter or a solid-state transformer. This flexibility in component selection allows for customization to various applications, providing a balance between efficiency, cost, and size. The ability to dynamically adjust the intermediate voltage based on real-time measurements of the output voltage ensures consistent and reliable performance under a wide range of operating conditions, making it suitable for advanced electronic systems with extremely high power efficiency and density requirements. Attached Figure Description

[0014] The present invention will now be described with reference to the accompanying drawings, which are merely examples of the power converter and the method for converting input DC voltage to output DC voltage disclosed in the present invention, and are not intended to limit the invention.

[0015] Figure 1 An embodiment of the two-stage power converter architecture of this disclosure is shown; Figure 2Another embodiment of the two-stage power converter architecture of this disclosure is shown, wherein the second-stage open-loop DC-DC converter includes a plurality of open-loop DC-DC sub-converters connected in parallel; Figures 3A-3B Examples of switched-capacitor current multipliers and switched-capacitor voltage multipliers that can be used in a second-stage open-loop DC-DC converter are shown. Figure 4 An example of a solid-state transformer that can be used in a second-stage open-loop DC-DC converter is shown; Figure 5 An example of a two-stage power converter including a buck converter and a switched capacitor converter is shown; Figure 6 An example of a two-stage power converter including a resonant converter and a switched capacitor converter is shown; Figure 7 An example of a two-stage power converter including a linear regulator and a switched capacitor voltage multiplier is shown; Figure 8 An example of a two-stage power converter including a boost converter and a switched capacitor voltage multiplier is shown; Figure 9 An example of the process of regulating the output DC voltage is shown; Figure 10 A flowchart illustrating one embodiment of the method for converting an input DC voltage to an output DC voltage according to this disclosure is shown. Detailed Implementation

[0016] This disclosure relates to a power converter including a first-stage regulated DC-DC converter and a second-stage open-loop DC-DC converter. The first-stage regulated DC-DC converter is configured to convert an input DC voltage to an intermediate DC voltage, and the second-stage open-loop DC-DC converter is configured to convert the intermediate DC voltage to an output DC voltage for a load. A controller is used to regulate the regulated DC-DC converter based on a measurement of the output DC voltage. This regulation may have a target output DC voltage, which may also be referred to as a reference output DC voltage. The controller can control the first-stage regulated DC-DC converter to regulate the output DC voltage.

[0017] The input DC voltage can be received from an input source, such as an input power supply, which can include various types of DC power supplies, such as batteries, external DC power adapters, or renewable energy sources like solar panels. The input source can be an input DC current source, thereby delivering input DC current. The input source can also be an input DC voltage source, thereby delivering input DC voltage. In some embodiments, the input source can additionally provide input DC current, enabling the power converter to operate under a wide variety of input conditions. This flexibility allows the system to adapt the voltage and / or current input source to the specific requirements of the application.

[0018] Those skilled in the art will understand that, since the second stage is an open-loop DC-DC converter, adjusting the intermediate DC voltage will implicitly adjust the output DC voltage. In practice, adjusting the output DC voltage will involve measurement and feedback processes.

[0019] In the context of this disclosure, "open loop" or "open-loop" is used alternatively to describe a DC-DC converter stage that operates without active feedback control from its own output. That is, the output voltage or current of an open-loop converter is preferably not dynamically regulated by sensing and adjusting internal parameters based on real-time measurements of the output. Instead, the output can be determined primarily by the converter's internal configuration and the applied intermediate voltage. For example, a switched-capacitor voltage multiplier with a fixed topology can provide an output that is a predetermined multiple of the intermediate voltage, such as 2x or 3x, depending on its design.

[0020] While open-loop converters may not implement active closed-loop regulation, they can still be designed with passive components, internal timing, or fixed switching logic to contribute to stable and predictable performance. In some cases, limited control or selection mechanisms can be applied to the open-loop stage, such as enabling or disabling sub-converters or selecting between fixed configurations, but these actions are not based on real-time output feedback. This allows the second stage to remain simple, efficient, and compact, which is particularly advantageous for integrated applications requiring high power density or proximity to the load.

[0021] In a two-stage power converter architecture, regulating the output DC voltage involves precise control of the first stage (a regulated DC-DC converter), which indirectly controls the second stage (an open-loop DC-DC converter). The core mechanism of this regulation revolves around the first stage's ability to regulate an intermediate DC voltage, which is then fed into the second stage to generate the output DC voltage. Because the second stage operates in an open-loop configuration, it does not perform active regulation itself, but rather relies on the intermediate voltage provided by the first stage.

[0022] In one embodiment, the regulation process begins by measuring the DC output voltage supplied to the load. The actual output voltage can be continuously monitored using sensors or measurement circuitry, such as voltage dividers and / or analog-to-digital converters (ADCs). This measured voltage can be compared to a reference output voltage or a target output voltage, representing the desired operating voltage of the load. The controller receives the real-time measurement of the output voltage and compares it to the target value. If any deviation exists, whether due to changes in input voltage, load conditions, or other external factors, the controller calculates the necessary adjustments to bring the output voltage back within an acceptable range. This closed-loop feedback can be used to maintain a stable output voltage regardless of external disturbances.

[0023] The first stage of a regulating DC-DC converter is responsible for adjusting the intermediate DC voltage based on feedback from the controller. The controller sends control signals to the first stage to increase or decrease the intermediate voltage. For example, if the output voltage is too low (below the target), the controller increases the intermediate DC voltage by adjusting the duty cycle of the switching elements in the switch-mode converter; or, in the case of a linear regulator or resonant converter, by increasing the output voltage to increase the intermediate DC voltage.

[0024] In switch-mode converters, such as buck, boost, or buck-boost configurations, the controller adjusts the duty cycle of the switching transistors. A higher duty cycle increases the energy transferred from the input to the intermediate voltage, thereby increasing the intermediate DC voltage. Conversely, if the output voltage is too high, the controller reduces the duty cycle, thereby reducing the intermediate voltage and consequently the output voltage.

[0025] In a linear regulator, the control mechanism involves adjusting components (such as transistors) to more precisely regulate the intermediate voltage. While less efficient than a switch-mode converter, a linear regulator can provide very fine control over the intermediate voltage, thus ensuring highly stable output voltage regulation, especially in noise-sensitive applications.

[0026] In a resonant converter, the controller can adjust the resonant frequency or phase angle to control the power delivered to the intermediate voltage. This method is particularly effective in high-frequency applications where reducing switching losses is critical.

[0027] The open-loop second stage does not perform active regulation. Instead, it converts the intermediate DC voltage to the final output voltage based on a fixed conversion ratio. For example, if the second stage is implemented as a switched-capacitor voltage multiplier, it will multiply the intermediate voltage by a predetermined factor (e.g., 2 or 3) to produce the output voltage. Similarly, a switched-capacitor current multiplier will increase the current by a set factor depending on the configuration of the capacitors and switches.

[0028] Since the second stage does not dynamically adjust its conversion ratio, the responsibility for maintaining a stable output voltage lies with the first stage. The first stage must be precisely controlled to ensure that the intermediate voltage is appropriate for the desired output voltage. By fine-tuning the intermediate voltage, the controller ensures that the output voltage remains near the target value.

[0029] One of the advantages of this two-stage architecture is its adaptability to different input voltages and load conditions. When the input DC voltage fluctuates, the first stage can quickly respond and adjust the intermediate voltage to maintain a stable output voltage. For example, if the input voltage suddenly drops, the controller detects the corresponding drop in the output voltage and increases the duty cycle in the first stage or adjusts the components to boost the intermediate voltage. Similarly, if load demand changes—for example, if the load increases and requires more power—the controller can respond by increasing the intermediate voltage or increasing the current delivered by the first stage. This dynamic adjustment ensures that the power converter can cope with various conditions without compromising output voltage stability.

[0030] In the case where the second stage includes multiple open-loop sub-converters in parallel, the controller can further optimize the output voltage by selectively enabling or disabling certain sub-converters. For example, when the load is light, the controller can disable some sub-converters to improve efficiency and reduce unnecessary power consumption. When the load increases, the controller can enable additional sub-converters to provide more power.

[0031] When sub-converters have different fixed conversion rates, the controller can select the appropriate sub-converter to meet the output voltage requirements. This adds a layer of flexibility to the regulation process, enabling the system to handle a wide range of output voltages without the need for continuous adjustment of the intermediate voltage.

[0032] The controller can incorporate any suitable error compensation mechanism, such as proportional-integral-derivative (PID) control, to ensure the stability and responsiveness of the regulation process. PID control enables the controller to correct any errors in the output voltage in a smooth and stable manner, avoiding overshoot or oscillation. The proportional part addresses instantaneous errors, the integral part corrects for errors accumulated over time, and the derivative part helps predict future changes based on the rate of change of the error.

[0033] In more advanced implementations, the controller may also include predictive algorithms or adaptive control techniques to improve system responsiveness, especially in applications where load or input voltage changes rapidly.

[0034] In some cases, temperature monitoring can also be part of the regulation process, enabling the controller to adjust power delivery based on the temperature of critical components. If the temperature exceeds a certain threshold, the controller can reduce the intermediate voltage or disable certain sub-converters to prevent overheating.

[0035] In one embodiment of this disclosure, the first-stage regulated DC-DC converter may be a linear regulator, a switch-mode converter, or a resonant converter. A linear regulator is a voltage regulator that uses active devices, such as transistors or operational amplifiers, to maintain a constant output voltage regardless of changes in input voltage or load conditions. It operates by constantly adjusting the resistance in its components, thereby dissipating excess power as heat. While it offers excellent output voltage regulation and low noise, it is less efficient compared to other types of converters, especially when there is a large difference between the input and output voltages. This makes it suitable for applications with extremely high noise sensitivity and simplicity requirements, but less suitable for applications with high efficiency requirements.

[0036] On the other hand, switch-mode converters operate by rapidly switching a series of electronic switches (typically transistors) on and off, thereby transferring energy from input to output in discrete packets. These converters, such as buck, boost, or buck-boost configurations, offer higher efficiency by reducing power losses in the switching elements and by efficiently storing and releasing energy using inductors and capacitors. Switch-mode converters are well-suited for applications requiring high efficiency and compact size, such as in battery-powered devices or where thermal management is a concern.

[0037] A resonant converter is a specialized form of switch-mode converter that uses a resonant circuit, typically composed of inductors and capacitors, to modulate the switching waveform in a manner that minimizes switching losses. This allows operation at higher frequencies with reduced electromagnetic interference (EMI) and increased efficiency, making resonant converters ideal for high-frequency applications or situations where minimizing EMI is critical. The choice among these options for the first-stage regulated DC-DC converter depends on specific application requirements, such as the desired balance between efficiency, size, noise, and complexity.

[0038] In one embodiment of this disclosure, the second-stage open-loop DC-DC converter can be implemented as a switched-capacitor current multiplier or a switched-capacitor voltage multiplier. These converters do not rely on magnetic components such as inductors, making them compact and suitable for integration into space-constrained environments or environments requiring high-frequency operation. Switched-capacitor current multipliers operate by transferring charge between capacitors in a manner that effectively increases the current supplied to the load. This is particularly useful in applications where the load requires a higher current than that directly supplied by the first stage.

[0039] On the other hand, switched-capacitor voltage multipliers increase voltage by stacking charge from multiple series capacitors during the discharge phase. This allows the output voltage to be a multiple of the input or intermediate voltage, making it suitable for applications requiring a significant voltage increase, such as bias circuits or sensor power supplies. Both types of switched-capacitor converters can be configured to achieve high efficiency through optimized switching frequency and capacitor size design, which is especially important in the open-loop stage, where the absence of feedback regulation means the converter must be inherently efficient to maintain overall system performance.

[0040] In one embodiment of this disclosure, the second-stage open-loop DC-DC converter can be configured as a solid-state transformer. This solid-state transformer can be designed to perform DC-DC conversion. Solid-state transformers replace traditional magnetic transformers with semiconductor-based components, enabling operation at higher frequencies and potentially allowing for smaller, lighter designs. Solid-state transformers typically include high-frequency switching elements, such as transistors, and utilize these elements to achieve voltage conversion and isolation. This is particularly advantageous in applications requiring isolation between the input and output stages, such as in grid-connected power supplies or systems where safety is a concern.

[0041] Solid-state transformers can also provide additional functionality, such as bidirectional power flow, which is very useful in applications involving energy storage or renewable energy, where power may need to be transferred bidirectionally between the grid and storage elements. The high efficiency of solid-state transformers in the open-loop stage contributes to the overall performance of the power converter, especially when there are significant differences between input and output voltage levels and conventional magnetic transformers would be too bulky or inefficient.

[0042] In another embodiment of this disclosure, the second-stage open-loop DC-DC converter can be configured to provide a discrete multiple of the intermediate DC voltage to the output DC voltage. By using a discrete multiple, the design of the second-stage converter can be simplified, thereby reducing the need for complex control circuitry and allowing for a more compact and efficient implementation.

[0043] For example, if the intermediate voltage is set as the base value, the second stage can deliver an output voltage that is a simple multiple of that base value, such as 2, 3, or 4 times the intermediate voltage. Using discrete multiples makes it easy to expand the power converter to meet different output voltage requirements by simply adjusting the configuration of the second stage.

[0044] The second-stage open-loop DC-DC converter can include multiple open-loop DC-DC sub-converters connected in parallel. This architecture enhances the scalability and flexibility of the power converter. By distributing the load across multiple sub-converters, the system can handle higher power levels or provide redundancy in case of sub-converter failure, which is especially important in applications where reliability is critical. Each sub-converter can be designed to handle a portion of the total power, thereby reducing thermal and voltage stress on individual components and improving the overall efficiency and lifespan of the converter.

[0045] Parallel sub-converters also allow for dynamic load sharing, where power output is evenly distributed among the active sub-converters. This can be particularly useful in applications with varying load conditions, where the system can dynamically adjust the number of active sub-converters based on current load demands to ensure optimal efficiency and performance. The modular nature of this configuration also makes it easier to upgrade or expand the power converter by adding or removing sub-converters as needed.

[0046] In this disclosure, the second-stage open-loop DC-DC converter can be implemented in a variety of configurations. In some embodiments, the second stage may include a single sub-converter that performs the entire conversion from an intermediate DC voltage to an output DC voltage or current. In such cases, the second stage may be implemented, for example, as a single switched-capacitor voltage multiplier or a solid-state transformer. In other embodiments, the second stage may be divided into multiple sub-converters, such as a plurality of sub-converters, which may operate in parallel or may be selectively enabled based on operating conditions. Therefore, the expression "second stage" should be broadly understood to include both a single converter stage, such as a single sub-converter, and a composite stage consisting of, for example, at least two sub-converters or a plurality of sub-converters. This flexibility allows power converter architectures to be customized to different design and performance requirements, ranging from compact, low-power implementations to scalable, high-current applications.

[0047] In one embodiment, the power converter includes multiple open-loop DC-DC sub-converters connected in parallel, configured to receive an intermediate DC voltage as input. These sub-converters are capable of generating multiple output DC voltages or multiple output DC currents. This configuration allows for efficient power distribution to multiple loads or different portions of a single load by enabling parallel operation. The flexibility of generating multiple outputs makes this architecture particularly advantageous in applications requiring different voltage or current levels, such as systems powering different components with different electrical requirements.

[0048] In some implementations, multiple parallel open-loop DC-DC sub-converters are implemented as parallel switched-capacitor converters. Switched-capacitor topologies are particularly well-suited for this purpose due to their high efficiency and compact design. These converters rely on capacitor charge transfer mechanisms to perform voltage or current conversion without bulky inductor components. Using parallel switched-capacitor converters further increases the system's power density while maintaining high conversion efficiency.

[0049] In another embodiment, multiple open-loop DC-DC sub-converters connected in parallel can be configured to operate at the same or different conversion rates. This arrangement provides additional flexibility, enabling the power converter to supply different voltage or current levels to various loads, or to optimize power delivery based on the specific needs of a single load. The controller can be configured to individually enable or disable the open-loop DC-DC sub-converters, thereby allowing for dynamic load management and efficient operation. By selectively activating the sub-converters, the system can tailor its output to different load conditions, minimize energy losses, and improve overall reliability.

[0050] These features collectively enhance the versatility and efficiency of the power converter, enabling its deployment in a wide range of applications, from consumer electronics to industrial systems, requiring compact, high-performance, and scalable power delivery. Parallel configurations of sub-converters can enhance system robustness by providing redundancy, as individual sub-converters can be disabled without affecting the operation of the remaining sub-converters.

[0051] In one embodiment of this disclosure, multiple open-loop DC-DC sub-converters connected in parallel may be parallel switched-capacitor converters. This implementation leverages the advantages of switched-capacitor technology, such as high efficiency and compact size, while also providing the advantages of parallel operation. Parallel switched-capacitor converters are particularly useful in applications requiring high output current or redundancy to ensure continuous operation in the event of component failure. By employing a parallel configuration, the power converter maintains high efficiency even at higher power levels because each sub-converter operates within its optimal range.

[0052] Using parallel switched-capacitor converters also allows for more flexible management of output voltage and current. For example, the controller can activate or deactivate individual sub-converters to match load demand, which is highly advantageous in systems with fluctuating power requirements. This approach not only improves efficiency but also enhances the reliability and lifespan of the power converter by reducing stress on individual components.

[0053] Multiple open-loop DC-DC sub-converters connected in parallel can have the same or different conversion rates, and the controller can be configured to enable or combine the open-loop DC-DC sub-converters individually or according to a predetermined fixed power conversion configuration. This feature allows for precise control of the output characteristics of the power converters. By configuring sub-converters with different conversion rates, the system can provide a wide range of output voltage or current without complex circuitry or multiple converters.

[0054] The controller's ability to selectively activate or combine sub-converters based on real-time conditions or pre-defined configurations enables efficient power management. For example, in the event of a sudden increase in load demand, the controller can quickly activate additional sub-converters to meet the demand without compromising system stability or efficiency. This flexibility is particularly useful in applications with dynamic load profiles, such as telecommunications or computing systems, where power demands can change rapidly and unpredictably.

[0055] In one embodiment of this disclosure, the second-stage open-loop DC-DC converter may include multiple open-loop DC-DC sub-converters that can be combined to provide a combined fixed conversion rate. This configuration is advantageous in systems where stable and accurate output voltage and the ability to extend output power are important. By combining multiple sub-converters with a fixed conversion rate, the system ensures that the output voltage remains within the desired range even as power requirements change.

[0056] This approach is also useful in applications where the power converter needs to support multiple operating modes or requires different output levels under varying conditions. The ability to combine sub-converters provides a simple way to expand the converter's capabilities, enabling it to meet diverse power demands without significant changes to the overall design. Furthermore, this modularity simplifies maintenance and upgrades, as sub-converters can be easily added, removed, or replaced as needed.

[0057] In the power converters disclosed herein, the second power density of the second-stage open-loop DC-DC converter can be higher than the first power density of the first-stage regulated DC-DC converter. Power density refers to the amount of power that can be delivered per unit volume of the converter. Higher power density in the second stage allows for a more compact design, which is particularly advantageous in space-constrained applications such as portable electronics, aerospace, or automotive applications. This higher power density in the second stage is achieved by the fact that the second stage is open-loop and is further enhanced by design optimizations for efficiency and minimizing the use of bulky components, such as inductors, which are typically required in the first-stage regulated converter.

[0058] The first current density can be between 0.1 A / mm² and 1 A / mm², for example, between 0.1 A / mm² and 0.5 A / mm², or between 0.5 A / mm² and 1 A / mm². The second current density can be between 0.8 A / mm² and 10 A / mm², for example, between 0.8 A / mm² and 5 A / mm², or between 5 A / mm² and 10 A / mm².

[0059] This design allows the second stage to be placed closer to the load, thereby shortening interconnect length and reducing associated power losses. By minimizing the distance between the second stage and the load, the system can achieve higher overall efficiency and better thermal management. The compact size of the second stage also makes it easier to integrate into confined spaces, such as within a device housing or close to sensitive components requiring precise voltage regulation.

[0060] The second-stage power efficiency of an open-loop DC-DC converter can be higher than the first-stage power efficiency of a regulated DC-DC converter. Power efficiency is a measure of how well a converter converts input power to desired output power with minimal losses. Higher power efficiency in the second stage means the converter can deliver more power to the load with less input power, which is particularly advantageous in applications requiring compact design and high efficiency. By optimizing the power efficiency of the second stage, the entire power conversion system can achieve higher efficiency, reduced heat loss, and improved load reliability. Furthermore, this architecture allows the second stage to be positioned closer to the load, minimizing transmission losses and further improving system performance under various operating conditions.

[0061] The first power efficiency can be between 90% and 95%, for example, between 90% and 91%, between 91% and 92%, between 92% and 93%, between 93% and 94%, or between 94% and 95%. The second power efficiency can be between 94% and 98%, for example, between 94% and 95%, between 95% and 96%, between 96% and 97%, or between 97% and 98%.

[0062] In the context of this disclosure, the term "current density" can be understood as the current processed or delivered by the first and / or second stages of a converter, expressed per unit area or volume of the relevant stage. In one example, current density can be measured in amperes per square millimeter (A / mm²), referring to the cross-sectional area of ​​the conductive or active power processing region. Alternatively, current density can also be defined per unit volume of the power converter stage (e.g., the first and / or second stage), particularly in systems associated with vertical integration or three-dimensional layout. The choice between area-based or volume-based current density may depend on the specific packaging and design techniques used, and both approaches are considered within the scope of this disclosure.

[0063] To evaluate current density in a meaningful and consistent manner, it is often useful to define the physical boundaries of the power stage under test. For example, in an integrated circuit implementation, the footprint or volume of the second-stage open-loop DC-DC converter can be determined by the area of ​​the active silicon; or in a discrete implementation, by the layout of the associated PCB modules. Current density measurements can then be performed under representative operating conditions, such as steady-state output current delivery and at a predefined ambient or junction temperature, preferably between 25°C and 85°C, depending on the intended application.

[0064] Similarly, "power efficiency" can be expressed as the ratio of output power to input power for a given stage, typically under defined load and input voltage conditions. In reality, power efficiency can be affected by switching losses, conduction losses, and the performance of passive components. For consistent interpretation, efficiency can be measured over an operating point range, for example, at different load currents / voltages, input voltages, and temperatures, and the reported values ​​can correspond to peak or average efficiency within a defined load curve. In many cases, specifying the output load (e.g., resistive load or analog application curve), input voltage range (e.g., fixed or swept), and environmental conditions during the measurement period can be helpful.

[0065] Generally, the higher current density and / or power efficiency of a second-stage open-loop converter compared to the first stage can be attributed to the use of a simplified topology, reduced switching overhead, and larger magnetic components. In some implementations, the second stage can be physically smaller or located closer to the load, thereby reducing interconnect resistance and improving thermal management, which also contributes to increased current handling per unit area.

[0066] In one embodiment of this disclosure, the first-stage regulated DC-DC converter may include a switch-mode converter, preferably a buck converter, while the second-stage open-loop DC-DC converter may include a switched-capacitor converter. This particular combination is advantageous in applications requiring a significant voltage reduction. The buck converter efficiently reduces the input voltage to an intermediate level, which is then further processed by the switched-capacitor converter to achieve the desired output voltage.

[0067] A buck converter operates by rapidly switching a series of transistors on and off, thereby controlling the amount of energy transferred from the input to the output. This process is highly efficient, especially when the input voltage is significantly higher than the desired output voltage. A switched-capacitor converter then takes this intermediate voltage and uses a series of capacitors and switches to achieve the final output voltage, which can be lower than, equal to, or higher than the intermediate voltage, depending on the configuration.

[0068] This combination is useful, for example, in digital circuits where precise voltage regulation is required to ensure reliable operation of microprocessors and other digital components. Using a switched-capacitor converter in the second stage allows for a compact design that can be integrated close to the load, thereby reducing power losses and improving overall system efficiency.

[0069] In another embodiment of this disclosure, the first-stage regulated DC-DC converter includes a resonant converter, while the second-stage open-loop DC-DC converter may include a switched-capacitor converter. This combination leverages the capabilities of both technologies to achieve high efficiency and low-noise operation. The resonant converter operates by constructing a resonant circuit using inductors and capacitors, which allows for smooth and efficient energy transfer at high frequencies.

[0070] This type of converter is useful in applications where minimizing electromagnetic interference (EMI) is critical, such as communication systems or medical devices. The second-stage switched-capacitor converter further processes the intermediate voltage from the resonant converter to achieve the final output voltage. The absence of inductors in a switched-capacitor converter means a compact overall design and low EMI generation, making this combination suitable for sensitive electronic systems.

[0071] With this combination, the intermediate DC voltage can be lower than the input DC voltage, and the output DC voltage can be lower than the intermediate DC voltage. This voltage hierarchy is common in applications requiring significant voltage reduction, such as low-voltage power supplies for digital circuits or portable devices. By first reducing the input voltage to an intermediate level, the system can optimize each stage for efficiency and performance.

[0072] In this configuration, the first stage reduces the voltage to a manageable level, and then the second stage further reduces that level to meet the specific requirements of the load. This approach allows for precise control of the output voltage in a highly efficient configuration, ensuring that the output voltage remains stable and within the desired range even as input voltage or load conditions change. The ability to step down the voltage in stages also reduces thermal stress on individual components, thereby improving the overall reliability and lifespan of the power converter.

[0073] In one embodiment of this disclosure, the first-stage regulated DC-DC converter may include a linear regulator, and the second-stage open-loop DC-DC converter may include a switched-capacitor voltage multiplier.

[0074] In this configuration, the second-stage switched-capacitor voltage multiplier can boost the voltage to the desired level without the need for an inductor or transformer. This configuration is advantageous in systems with limited space where the use of magnetic components would introduce unwanted noise or require additional shielding. The simplicity and low noise of the linear regulator, combined with the high efficiency and compactness of the switched-capacitor voltage multiplier, makes it a powerful solution for precise power supply.

[0075] In this embodiment, the output DC voltage can be higher than the input DC voltage. This is common in applications where the power supply needs to provide a higher voltage than the available input, such as battery-powered devices or energy harvesting systems. By using a voltage multiplier in the second stage, the system can achieve the required voltage boost with high efficiency and a minimal number of components.

[0076] This approach is particularly useful in applications where the power supply must be able to deliver the voltage required for proper device operation. The ability to efficiently boost voltage allows the use of lower-voltage batteries or energy sources that can be smaller, lighter, and cheaper, while still providing the power required by the application.

[0077] In one embodiment, the first-stage regulated DC-DC converter includes a switch-mode converter, preferably a boost converter, while the second-stage open-loop DC-DC converter may include a switched-capacitor voltage multiplier. This combination is particularly useful in applications requiring a significant voltage boost, such as for power supplies to sensors, communication devices, or other electronic devices operating at voltages higher than the available input.

[0078] In this configuration, the boost converter efficiently raises the input voltage to an intermediate level, which is then further increased by a switched-capacitor voltage multiplier to achieve the final output voltage. This configuration enables a highly efficient and compact power supply capable of delivering high voltage with minimal losses, making it suitable for applications with stringent voltage and size requirements.

[0079] The output DC voltage can be significantly higher than the input DC voltage. More specifically, in one embodiment of this disclosure, the output DC voltage can be at least 10 times higher than the input DC voltage, for example, at least 2 times higher, at least 5 times higher, or at least 1.5 times higher. This voltage level is advantageous in various high-voltage power supplies, such as those for industrial equipment or high-power LEDs. By combining a boost converter with a switched-capacitor voltage multiplier, this system can achieve this level of voltage boost with high efficiency and minimal footprint.

[0080] This disclosure also relates to an electrical device comprising: a power converter according to any of the foregoing embodiments; and a load powered by the power converter. The electrical device can be any electrical equipment using a power converter. In such a device, a second-stage open-loop DC-DC converter can be placed closer to the load, thereby reducing losses associated with long interconnects and improving overall system performance.

[0081] By placing the second-stage open-loop converter closer to the load, the interconnect length between the converter and the load can be minimized. This reduction in interconnect length decreases resistive losses as current flows through the connecting wires or traces. In high-current applications, these losses can be significant, leading to power waste and reduced efficiency. Therefore, shortening the interconnect length improves overall power delivery efficiency, ensuring a higher proportion of the power generated by the converter reaches the load.

[0082] Furthermore, placing the secondary stage closer to the load reduces the likelihood of voltage drop along the interconnect. Voltage drop can be problematic in low-voltage, high-current systems, where even small amounts of resistance can cause a significant decrease in delivered voltage. By minimizing voltage drop, the system can deliver a more consistent and reliable voltage to the load, thereby improving the overall performance and lifespan of the electrical installation.

[0083] The compact design of second-stage open-loop DC-DC converters typically utilizes switched capacitors or other high-efficiency components, making them ideal for direct integration into or near the load. This proximity not only improves electrical performance but also simplifies system design by reducing the complexity of the power distribution network. In space-constrained applications, such as portable electronics, automotive systems, or aerospace environments, this integration allows for more efficient use of available space without compromising power delivery quality.

[0084] In one embodiment, the second-stage open-loop DC-DC converter can be housed within a load package that accommodates both the load and the converter. This close connection between the converter and the load further reduces power distribution losses and improves thermal management. By placing the converter and load in the same location, the heat generated during the power conversion process can be managed more effectively through a shared cooling mechanism or heat sink, thereby preventing localized overheating and extending the system's operational life.

[0085] In another embodiment of the power converter disclosed herein, the power converter and load can be housed within a common package. This integration offers advantages in terms of efficiency and space optimization. For example, in systems such as system-on-a-chip (SoC) architectures or integrated power modules, placing the power converter and load within the same package allows for precise control of power delivery and the use of shorter, optimized electrical connections. Due to fewer external interconnects, these systems benefit from reduced electromagnetic interference (EMI), improved thermal performance, and enhanced reliability. The common package can be an integrated circuit (IC), preferably a single-chip or semiconductor package, more preferably a system-on-a-chip (SoC) or system-in-package (SiP).

[0086] Furthermore, integrating the power converter and load into a common package allows for more efficient management of parasitic effects, such as inductance and capacitance, which can degrade the performance of high-speed or high-frequency power converters. By minimizing the physical distance between the converter and the load, this design reduces parasitic inductance, which could otherwise cause oscillations, voltage spikes, or reduced conversion efficiency in high-frequency switching applications.

[0087] This disclosure also relates to a method for converting an input DC voltage to an output DC voltage, the method comprising the steps of: providing a power converter comprising: a first-stage regulated DC-DC converter adapted to receive input DC power and generate an intermediate DC voltage; a second-stage open-loop DC-DC converter adapted to receive the intermediate DC voltage from the first-stage regulated DC-DC converter and generate an output DC voltage; and measurement-controlled regulation of the regulated DC-DC converter based on the output DC voltage. The regulation may have a target output DC voltage, which may also be referred to as a reference output DC voltage. The controller may control the first-stage regulated DC-DC converter to regulate the output DC voltage.

[0088] Those skilled in the art will understand that the method of converting an input DC voltage to an output DC voltage disclosed herein can be implemented using any embodiment of the power converter disclosed herein, and vice versa.

[0089] Those skilled in the art will understand that the controller can be implemented in various forms depending on specific application requirements. The processing unit can include, but is not limited to, a general-purpose microcontroller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). The processing unit can be a single-core processor configured to execute control algorithms that manage the regulation of intermediate and output DC voltages. Alternatively, in more complex systems, the processing unit can be a multi-core processor. In certain cases, the processing unit may also include hardware accelerators designed to perform specific tasks more efficiently. For example, hardware accelerators can be used to handle real-time control functions such as pulse width modulation (PWM) signal generation or Fast Fourier Transform (FFT) calculations for analyzing power signals. Depending on the architecture, these accelerators can be integrated with a central processing unit (CPU) or can operate independently. Both the hardware accelerator and the CPU can be connected to data communication infrastructure, such as a high-speed bus or a network on-chip (NoC), to facilitate fast and efficient communication between system components. In some embodiments, the processing unit can be a digital signal processor (DSP). The processing unit can also be implemented using an application-specific integrated circuit (ASIC), which can be custom-designed to perform the specific control tasks required by the power converter, or using a field-programmable gate array (FPGA).

[0090] The processing unit may also include or interact with external memory components such as RAM, ROM, or flash memory, which store control algorithms, operating parameters, and other data required for power management processes. Depending on the system architecture, the processing unit may access these memory components via a dedicated memory interface or a shared data bus.

[0091] The processing unit can also be connected to various sensors and actuators, such as voltage and current sensors, temperature sensors, and control switches. These components provide the processing unit with real-time feedback on system operating conditions, allowing it to adjust the operation of the power converter as needed. For example, the processing unit can use data from voltage and current sensors to adjust the duty cycle of the first-stage regulating DC-DC converter, or to enable or disable sub-converters in the second stage to optimize power delivery. Detailed description of the attached diagram

[0092] The present invention will now be described in more detail with reference to the accompanying drawings. The drawings are merely illustrative and intended to illustrate some features of the power converter and the method for converting input DC voltage to output DC voltage, and are not intended to limit the scope of the invention.

[0093] Figure 1 An embodiment of the multi-stage power converter architecture of this disclosure is shown. Figure 1An embodiment of a two-stage power converter architecture 100 is illustrated. The power converter includes an input source 101, a first-stage regulated DC-DC converter 102, a second-stage open-loop DC-DC converter 103, a controller 104, and a load 105. The input source 101 is adapted to provide an input DC voltage or input DC current to the power converter. The input source can include various types of DC power supplies, such as batteries, external DC power adapters, or renewable energy sources like solar panels. By allowing input voltage and / or current sources, the system is versatile and can be adapted to a wide variety of input conditions based on specific applications. The first-stage regulated DC-DC converter 102 is configured to convert the input DC voltage received from the input source 101 into an intermediate DC voltage. This first-stage regulation provides precise control over the intermediate voltage, thereby compensating for variations in input source or load demands. By ensuring a stable intermediate voltage, the first stage improves the overall reliability of the system and reduces stress on components in subsequent stages. This intermediate DC voltage is then provided to the second-stage open-loop DC-DC converter 103, which converts the intermediate voltage into a final output DC voltage. The second stage operates in an open-loop configuration with a fixed conversion ratio, enabling high efficiency and simplified design. The absence of active regulation in the second stage reduces control complexity and contributes to higher power density, making it particularly suitable for applications requiring compact and efficient power delivery. Controller 104 regulates the first-stage regulated DC-DC converter 102 based on feedback obtained from the output DC voltage delivered to the load 105. By comparing the measured output DC voltage with the target output voltage, the controller dynamically adjusts the intermediate voltage generated by the first stage. This ensures that the final output voltage remains stable and within the desired range, even with variations in input voltage or load conditions. By focusing control effects on the first stage, the regulation process is simplified, while the second stage remains optimized for efficiency. Load 105 represents an electrical or electronic system that receives the output DC voltage. The load may include, for example, electronic circuitry, a processor, or other components requiring reliable, precise power delivery. The compact nature of the second stage allows it to be placed closer to the load, minimizing interconnect-related losses and improving overall system performance.

[0094] Figure 2 Another embodiment of the multi-stage power converter architecture of this disclosure is shown, wherein the second-stage open-loop DC-DC converter includes a plurality of open-loop DC-DC sub-converters connected in parallel. Figure 2 Further embodiments of a multi-stage power converter architecture 100, such as a two-stage power converter architecture, are illustrated. (Compared to...) Figure 1The illustrated embodiment is similar, and the power converter includes an input source 101, a first-stage regulated DC-DC converter 102, a second-stage open-loop DC-DC converter 103, a controller 104, and a load 105. In this embodiment, the second-stage open-loop DC-DC converter 103 includes multiple open-loop DC-DC sub-converters 106 connected in parallel. The input source 101 provides the power converter with an input DC voltage or input DC current. As previously described, the input source can include various DC power supplies, such as batteries, external DC power adapters, or renewable energy sources. The first-stage regulated DC-DC converter 102 receives the input voltage from the input source and converts it into an intermediate DC voltage. This intermediate voltage is then provided to the second-stage open-loop DC-DC converter 103. The first stage ensures stable regulation of the intermediate voltage, thereby enabling optimal operation of the second stage. The second-stage open-loop DC-DC converter 103 includes multiple open-loop DC-DC sub-converters 106 operating in parallel. Each sub-converter 106 receives the intermediate voltage from the first stage and participates in generating the final output DC voltage provided to the load 105. The use of multiple sub-converters in parallel allows the second stage to distribute the power load across the sub-converters, reducing stress on individual components and improving overall system efficiency and reliability. Furthermore, the modular design of the second stage allows for the activation or deactivation of individual sub-converters as needed, providing scalability and flexibility to adapt to different load conditions. Controller 104 monitors the output DC voltage delivered to load 105 and regulates the operation of the first stage 102. By comparing the measured output voltage with the target output voltage, the controller dynamically adjusts the intermediate voltage provided by the first stage to maintain stable and accurate power delivery. Additionally, the controller can selectively activate or deactivate individual sub-converters 106 in the second stage based on current load demand, thereby optimizing performance and efficiency. Load 105 receives the final output DC voltage from the second-stage open-loop DC-DC converter 103. The parallel arrangement of the sub-converters in the second stage enables efficient power delivery while minimizing losses, making this architecture particularly suitable for high-power applications or scenarios requiring redundancy and high reliability.

[0095] Figure 3A and Figure 3B Examples of switched-capacitor current multipliers and switched-capacitor voltage multipliers are shown, which can be used in a second-stage open-loop DC-DC converter. Figure 3A and Figure 3B Two examples of implementations of a second-stage open-loop DC-DC converter are shown, in particular, which use a switched-capacitor topology to achieve current multiplication or voltage multiplication. Figure 3A An embodiment of a switched-capacitor current multiplier is shown. This switched-capacitor current multiplier receives an input voltage at an input terminal labeled "Input". The device includes an input capacitor C. INFlying capacitor (C) FLY and output capacitor period C OUT Flying capacitor C FLY Charge is efficiently transferred by switching between different configurations using a series of switches driven by a control circuit. By properly sequencing the switches, the circuit increases the current delivered to the output while maintaining the input voltage level. Output capacitor C OUT The final output voltage delivered to the load connected to the output terminal marked "Output" is smoothed or filtered. This implementation is particularly advantageous for applications requiring high output current while maintaining a compact and efficient design, as it eliminates the need for bulky magnetic components such as inductors. Figure 3B An embodiment of a switched-capacitor voltage multiplier is shown. (Compared to...) Figure 3A Similarly, the circuit includes an input capacitor C. IN Flying capacitor CFLY and output capacitor C OUT The input voltage is received at the terminal marked "Input". Flying capacitor C FLY The capacitor is alternately charged and discharged through a controlled switch to superimpose voltages and increase the output voltage. Output capacitor C OUT The resulting higher voltage is stabilized or filtered and then supplied at the output terminal marked "Output". This configuration is particularly advantageous for applications requiring a significant voltage boost, providing high efficiency without relying on inductors or transformers. Figure 3A and Figure 3B Both switched-capacitor implementations are compact and efficient, making them ideal for integration into space- and weight-constrained systems. These designs are inherently optimized for open-loop operation, reducing complexity and ensuring high power density. By selecting the current multiplier based on application requirements… Figure 3A ) or voltage multiplier ( Figure 3B The system can provide flexible and efficient power conversion tailored to load requirements.

[0096] Figure 4 An example of a solid-state transformer is shown, which can be used in a second-stage open-loop DC-DC converter. Figure 4 An embodiment of a second-stage open-loop DC-DC converter implemented as an LLC resonant converter is shown. The LLC resonant converter is designed to achieve efficient DC-DC conversion by utilizing the resonance between inductive and capacitive elements, thereby minimizing switching losses and electromagnetic interference (EMI). This topology is particularly advantageous for applications requiring high efficiency, compact design, and smooth power delivery.

[0097] The circuit receives an input DC voltage at the input terminal labeled "Input". The primary side includes a full-bridge switching configuration, where the switching of, for example, MOSFETs is controlled to generate an alternating current (AC) waveform. This waveform drives a resonant tank circuit comprising an inductor and a capacitor. This tank circuit includes a resonant inductor and a resonant capacitor, which together form an LLC resonant network. Resonance allows for efficient energy transfer by operating the switches at frequencies close to or equal to the resonant frequency, significantly reducing switching losses. The AC signal generated by the resonant circuit is transmitted through a transformer, which provides electrical isolation and allows voltage scaling according to the turns ratio of the transformer windings. On the secondary side, a rectified AC signal is converted back to DC voltage using a rectifier circuit, typically including diodes or synchronous switches. The rectified voltage is then filtered and stabilized by an output capacitor to ensure a smooth output DC voltage is delivered at the terminal labeled "Output". Figure 4 The illustrated LLC resonant converter offers several advantages, including high efficiency, reduced heat loss, and increased rate density due to soft switching (zero-voltage switching or zero-current switching). The absence of significant switching losses allows the converter to operate at higher frequencies, enabling the use of smaller passive components and more compact designs. This implementation is particularly advantageous for high-power applications where efficiency and thermal performance are critical, such as in server power supplies, automotive systems, and telecommunications equipment.

[0098] Figure 5 An example of a two-stage power converter, including a buck converter and a switched capacitor converter, is shown. Figure 5 An example of a two-stage power converter architecture is shown, where the first stage is implemented as a buck converter and the second stage as a switched-capacitor converter. This embodiment highlights the advantage of combining a regulated buck converter with a compact and efficient switched-capacitor converter to achieve precise power conversion with high efficiency. The circuit begins by receiving an input DC voltage at the input terminal labeled "Input". The first stage, shown in the left portion of the figure, is a buck converter that includes two switching elements controlled by S1 and S2, an inductor, and an input capacitor C. IN This buck converter reduces the input DC voltage to a regulated intermediate voltage. This intermediate voltage serves as the input to the second stage and is dynamically controlled by a controller based on feedback signals. The controller, shown at the bottom of the figure, generates control signals S1 and S2 for the first-stage switching elements to regulate the intermediate voltage. The controller also manages the operation of the second-stage switched-capacitor converter by controlling additional switches in the second stage. The controller operates based on measurements of the output DC voltage, ensuring the final output remains stable and within the target range. The second stage, located on the right side of the figure, comprises a switched-capacitor converter. This converter includes a capacitor C. FLY and C OUTAnd the associated switches. The switched capacitor topology alternates between the flying capacitor C in coordination with the switching sequence. FLY Charging and discharging are performed to achieve further voltage conversion. Output capacitor C OUT The final output DC voltage is smoothed and then fed to the output terminal labeled "Output". The combination of a buck converter in the first stage and a switched-capacitor converter in the second stage offers several advantages. The buck converter efficiently reduces the input voltage to an intermediate level, minimizing power loss during regulation. The switched-capacitor converter in the second stage further processes the intermediate voltage at a fixed conversion ratio, achieving high efficiency without the need for magnetic components such as inductors or transformers. This approach reduces size and weight, making it particularly suitable for applications with stringent space and thermal requirements.

[0099] Figure 6 An example of a two-stage power converter, including a resonant converter and a switched capacitor converter, is shown. Figure 6 An example of a two-stage power converter architecture is shown, where the first stage is implemented as a resonant converter and the second stage as a switched-capacitor converter. In this embodiment, the first stage uses a resonant converter, which efficiently converts the input DC voltage to an intermediate DC voltage. The resonant converter operates at a high frequency and relies on a resonant circuit consisting of an inductor and a capacitor. This design minimizes switching losses. The use of resonance improves overall efficiency and reduces electromagnetic interference (EMI), making it particularly suitable for noise-sensitive applications. The controller shown at the bottom of the figure generates control signals S1, S2, S3, and S4 for the first-stage switching elements to regulate the intermediate voltage. In other words, the control signals control the full-bridge switching configuration of the first stage. The controller also manages the operation of the second-stage switched-capacitor converter by controlling additional switches in the second stage. The controller operates based on measurements of the output DC voltage, ensuring that the final output remains stable and within the target range. Using C... OUT The output DC voltage is filtered. The second stage of the power converter is a switched-capacitor converter. The intermediate DC voltage generated by the resonant converter is further processed by the switched-capacitor converter to produce the final output DC voltage. The switched-capacitor converter uses controlled switches to alternately switch capacitor C... FLY Voltage conversion is achieved through charging and discharging. This design eliminates the need for magnetic components, enabling a compact implementation with high power density. The combination of a resonant converter in the first stage and a switched-capacitor converter in the second stage offers several advantages. The resonant converter provides efficient and low-noise conversion from input voltage to an intermediate voltage, while the switched-capacitor converter provides a compact and efficient solution for achieving the desired output voltage. Together, these two stages enable a highly efficient, compact power converter ideally suited for applications requiring low noise and minimal heat loss. Figure 6This demonstrates how the architecture leverages the capabilities of resonant capacitors and switched capacitors to provide a versatile and efficient power conversion solution.

[0100] Figure 7 An example of a two-stage power converter including a linear regulator and a switched capacitor voltage multiplier is shown. Figure 7 An example of a two-stage power converter architecture is shown, where the first stage is implemented as a linear regulator and the second stage as a switched-capacitor voltage multiplier. In this embodiment, the first-stage linear regulator converts the input DC voltage to an intermediate DC voltage. This linear regulator provides precise and highly stable voltage regulation by continuously adjusting passing elements such as transistors to maintain the intermediate voltage at a desired level. While linear regulators are less efficient than switched-capacitor converters, they offer significant advantages in terms of low noise and simplicity, making them ideal for applications requiring a clean and highly stable intermediate voltage. The second stage includes a switched-capacitor voltage multiplier, which further processes the intermediate DC voltage to produce the desired output DC voltage. The switched-capacitor voltage multiplier passes through a capacitor C... FLY Internal charge accumulation is used to increase the intermediate voltage. This design eliminates the need for an inductor or transformer, thus allowing for a compact and lightweight implementation with high power density. The output voltage uses the output capacitor C. OUTA stabilization process is performed to ensure a smooth and reliable power supply to the load, preferably connected to the output terminal marked "Output". A sensor senses the output DC voltage to provide error correction, which is processed by an error amplifier configured to signal control MOSFET M1 in the linear regulator, thereby adjusting the intermediate DC voltage. The error amplifier maintains precise regulation of the output voltage by comparing a feedback signal representing the actual output DC voltage with a reference target voltage. This comparison generates an error signal reflecting the deviation between the two values. The controller uses this error signal to dynamically adjust the operation of the first-stage regulated DC-DC converter, for example, by modifying the gate voltage on MOSFET M1 or other control parameters. By continuously minimizing the error signal, the error amplifier ensures that the output voltage remains stable and within the desired range, even under variations in input voltage or load conditions. Furthermore, the error amplifier contributes to system stability by facilitating smooth control adjustments and avoiding problems such as overshoot or oscillation. This feature is crucial for achieving reliable and accurate voltage regulation in a two-stage power converter architecture. The combination of the linear regulator in the first stage and the switched-capacitor voltage multiplier in the second stage offers several advantages. The linear regulator ensures precise and noiseless regulation of the intermediate voltage, which is particularly advantageous for sensitive applications such as analog circuits or low-noise power supplies. The switched-capacitor voltage multiplier in the second stage efficiently boosts the voltage to the desired output level without using bulky magnetic components, enabling a compact and efficient design.

[0101] Figure 8 An example of a two-stage power converter, including a boost converter and a switched capacitor voltage multiplier, is shown. Figure 8 An example of a two-stage power converter architecture is shown, where the first stage is implemented as a boost converter and the second stage as a switched-capacitor voltage multiplier. This embodiment demonstrates how the combination of a boost converter and a switched-capacitor voltage multiplier can achieve a significant voltage boost in a highly efficient and compact design. In this architecture, the first-stage boost converter receives the input DC voltage at the input terminal and converts it to a higher intermediate DC voltage. A capacitor C is used... IN The input DC voltage is filtered. The boost converter operates by using the inductance energy within the switched inductor L via a controlled switch to boost the input voltage while maintaining high efficiency. The intermediate voltage generated by the boost converter is used as the input to the second stage. The second stage includes a switched capacitor voltage multiplier. This second stage sequentially switches capacitor C in a controlled manner. FLY Charging and discharging further boost the intermediate voltage to the desired output DC voltage. This switched-capacitor voltage multiplier operates in an open-loop configuration with a fixed conversion ratio, eliminating the need for feedback regulation in this stage. Output capacitor C OUTA stable final voltage is delivered to the output terminals, ensuring a smooth and reliable power supply to the load. The controller is configured to provide signals S1 and S2 to control the switching of the boost converter. The controller receives feedback from the output voltage and is configured to adjust signals S1 and S2 to deliver the correct intermediate DC voltage to the second stage of the two-stage power converter. The combination of a boost converter and a switched-capacitor voltage multiplier offers significant advantages in applications requiring a substantial voltage boost. The boost converter efficiently boosts the input voltage to an intermediate level, while the switched-capacitor voltage multiplier provides additional voltage multiplication without requiring bulky magnetic components. This approach enables high power density, a compact form factor, and minimal switching losses, making it ideal for systems requiring high-voltage outputs, such as sensor power supplies, communication equipment, or industrial applications.

[0102] Figure 9 An example of the process of regulating the output DC voltage is shown. Figure 9 An example of the regulation process in a two-stage power converter architecture is shown, illustrating the interaction between the input DC voltage, intermediate DC voltage, output DC voltage, and corresponding control signals. Figure 9 Multiple functional blocks work together to regulate the power conversion process and ensure a stable output DC voltage. The system begins by providing an input DC voltage at the input terminal labeled "Input". The input voltage is processed by a first-stage regulated DC-DC converter, which is managed by control signals generated by PWM logic and level shifters. In this embodiment, the first stage is a buck converter. These control signals determine the switching operation of the first-stage transistors, thereby ensuring accurate generation of the intermediate DC voltage. A current sensor monitors the current flowing through the converter, providing real-time feedback to the system to enhance control and protection. The intermediate DC voltage is then provided to a second-stage open-loop converter, which processes it into the output DC voltage. In this embodiment, the second stage is a switched-capacitor converter. The output voltage is fed back to a compensation network via a voltage divider, which primarily generates voltage feedback proportional to the output voltage provided at the output terminal "Output". The compensation network works in conjunction with an error amplifier (EA) and a comparator (Comp). A reference generator provides a stable target voltage reference for comparison, while an oscillator sets the operating frequency of the regulation process. The compensation network processes error signals and stabilizes the system response, ensuring a smooth and accurate adjustment without oscillations. Additionally, a soft-start block is included to ensure a gradual and controllable system startup, preventing large inrush currents or voltage spikes. The output signal of the error amplifier influences the control loop, dynamically adjusting the operation of the first-stage PWM logic to regulate the intermediate voltage. By maintaining precise control of the intermediate voltage, the system indirectly and stably delivers the final output voltage to the load. Overall, Figure 9The complete regulation process of a two-stage power converter is demonstrated, highlighting the critical roles of feedback, error compensation, and control logic. The combination of real-time monitoring, compensation, and dynamic adjustment ensures that the output voltage remains stable and within the desired range even under input fluctuations or load changes. The inclusion of key functional blocks such as PWM logic, current sensors, and compensation networks ensures robust, efficient, and reliable power delivery at the output terminal.

[0103] Figure 10 A flowchart of one embodiment of a method 200 for converting an input DC voltage to an output DC voltage according to the present disclosure is shown. The method includes the steps of: providing a power converter including a first-stage regulated DC-DC converter and a second-stage open-loop DC-DC converter 201; and controlling the regulated DC-DC converter 202. Reference List

[0104] 100 – Power Converter 101 – Input Source / Input DC Voltage 102 – Level 1 103 – Level 2 104 – Controller 105 – Output DC Voltage / Load 106 – DC-DC Sub-converter More details

[0105] 1. A power converter, comprising: The first-stage regulated DC-DC converter is configured to convert the input DC voltage into an intermediate DC voltage. The second-stage open-loop DC-DC converter is configured to convert an intermediate DC voltage into an output DC voltage or output DC current to the load; and A controller configured to control a first-stage regulated DC-DC converter to regulate the output DC voltage or output DC current by adjusting an intermediate DC voltage based on measurements of the output DC voltage or output DC current and a target output DC voltage or target output DC current.

[0106] 2. The power converter according to Project 1, wherein the first-stage regulating DC-DC converter is a linear regulator, a switching mode converter, a switched capacitor converter, or a resonant converter.

[0107] 3. The power converter according to any of the preceding claims, wherein the second-stage open-loop DC-DC converter is a switched-capacitor current multiplier or a switched-capacitor voltage multiplier.

[0108] 4. The power converter according to any of the preceding claims, wherein the second-stage open-loop DC-DC converter is a solid-state DC-DC transformer.

[0109] 5. The power converter according to any of the preceding claims, wherein the second-stage open-loop DC-DC converter is configured to deliver a discrete multiple of the intermediate DC voltage to the output DC voltage or current.

[0110] 6. The power converter according to any of the preceding claims, wherein the second-stage open-loop DC-DC converter includes one or more open-loop DC-DC sub-converters connected in parallel, or multiple open-loop DC-DC sub-converters connected in parallel.

[0111] 7. The power converter according to Item 6, wherein a plurality of parallel open-loop DC-DC sub-converters are configured to take an intermediate DC voltage as input, thereby being configured to provide a plurality of output DC voltages or a plurality of output DC currents.

[0112] 8. The power converter according to any one of items 6-7, wherein one or more parallel open-loop DC-DC sub-converters or multiple parallel open-loop DC-DC sub-converters are parallel switched-capacitor converters.

[0113] 9. The power converter according to any one of items 6-8, wherein one or more parallel open-loop DC-DC sub-converters have the same or different conversion rates, and wherein the controller is configured to enable the open-loop DC-DC sub-converters individually.

[0114] 10. The power converter according to any of the preceding claims, wherein the second current density of the second-stage open-loop DC-DC converter is higher than the first current density of the first-stage regulated DC-DC converter.

[0115] 11. The power converter according to any of the preceding claims, wherein the second power efficiency of the second-stage open-loop DC-DC converter is higher than the first power efficiency of the first-stage regulated DC-DC converter.

[0116] 12. The power converter according to any one of the preceding claims, wherein the first-stage regulated DC-DC converter comprises a switch-mode converter, preferably a buck converter, and wherein the second-stage open-loop DC-DC converter comprises a switched-capacitor converter.

[0117] 13. The power converter according to any of the preceding claims, wherein the first-stage regulated DC-DC converter comprises a resonant converter, and wherein the second-stage open-loop DC-DC converter comprises a switched-capacitor converter.

[0118] 14. The power converter according to any one of items 12 to 13, wherein the intermediate DC voltage is lower than the input DC voltage, and wherein the output DC voltage is lower than the intermediate DC voltage.

[0119] 15. The power converter according to any of the preceding claims, wherein the first-stage regulated DC-DC converter includes a linear regulator, and wherein the second-stage open-loop DC-DC converter includes a switched-capacitor voltage multiplier.

[0120] 16. The power converter according to any of the preceding claims, wherein the output DC voltage is higher than the input DC voltage.

[0121] 17. The power converter according to item 16, wherein the output DC voltage is at least twice as high as the input DC voltage.

[0122] 18. The power converter according to any of the preceding claims, wherein the first-stage regulated DC-DC converter comprises a switch-mode converter, preferably a boost converter, and wherein the second-stage open-loop DC-DC converter comprises a switched-capacitor voltage multiplier.

[0123] 19. An electrical device comprising: The power converter according to any of the foregoing claims; and The load powered by this power converter.

[0124] 20. The electrical apparatus according to item 19, wherein the second-stage open-loop DC-DC converter is configured to be closer to the load than the first-stage regulated DC-DC converter.

[0125] 21. The electrical installation according to any one of items 19 to 20, wherein the second-stage open-loop DC-DC converter is disposed within a load package including the load, or wherein the power converter and the load are disposed within a common package.

[0126] 22. A method for converting an input DC voltage into an output DC voltage, the method comprising the following steps: A power converter is provided, which includes: The first-stage regulated DC-DC converter is adapted to receive input DC power and generate an intermediate DC voltage. A second-stage open-loop DC-DC converter, adapted to receive an intermediate DC voltage from a first-stage regulated DC-DC converter and generate an output DC voltage; and The first-stage regulating DC-DC converter is controlled to adjust the intermediate DC voltage based on the measurement of the output DC voltage and the target output DC voltage, thereby also adjusting the output DC voltage.

[0127] 23. The method described in item 22, using a power converter according to any one of items 1 to 18.

Claims

1. A power converter, characterized in that, include: A first-stage regulated DC-DC converter, configured to convert an input DC voltage into an intermediate DC voltage; A second-stage open-loop DC-DC converter is configured to convert the intermediate DC voltage into an output DC voltage or an output DC current to the load. as well as A controller configured to control a first-stage regulated DC-DC converter to regulate the output DC voltage or the output DC current by adjusting the intermediate DC voltage based on a measurement of the output DC voltage or the output DC current and a target output DC voltage or target output DC current.

2. The power converter according to claim 1, characterized in that, The first-stage regulating DC-DC converter is a linear regulator, a switch-mode converter, a switched-capacitor converter, or a resonant converter.

3. The power converter according to any one of the preceding claims, characterized in that, The second-stage open-loop DC-DC converter is a switched-capacitor current multiplier, a switched-capacitor voltage multiplier, or a solid-state DC-DC transformer.

4. The power converter according to any one of the preceding claims, characterized in that, The second-stage open-loop DC-DC converter is configured to deliver discrete multiples of the intermediate DC voltage to the output DC voltage or current.

5. The power converter according to any one of the preceding claims, characterized in that, The second-stage open-loop DC-DC converter includes multiple open-loop DC-DC sub-converters connected in parallel.

6. The power converter according to any one of the preceding claims, characterized in that, The plurality of parallel open-loop DC-DC sub-converters are configured to take the intermediate DC voltage as input, thereby being configured to provide a plurality of output DC voltages or a plurality of output DC currents, wherein the plurality of parallel open-loop DC-DC sub-converters are parallel switched-capacitor converters.

7. The power converter according to claim 6, characterized in that, The plurality of parallel open-loop DC-DC sub-converters have the same or different conversion rates, and wherein the controller is configured to enable each open-loop DC-DC sub-converter individually.

8. The power converter according to any one of the preceding claims, characterized in that, The second current density of the second-stage open-loop DC-DC converter is higher than the first current density of the first-stage regulated DC-DC converter.

9. The power converter according to any one of the preceding claims, characterized in that, The second power efficiency of the second-stage open-loop DC-DC converter is higher than the first power efficiency of the first-stage regulated DC-DC converter.

10. The power converter according to any one of the preceding claims, characterized in that, The first-stage regulated DC-DC converter includes a switch-mode converter, preferably a buck converter, and wherein the second-stage open-loop DC-DC converter includes a switched-capacitor converter.

11. The power converter according to any one of the preceding claims, characterized in that, The first-stage regulated DC-DC converter includes a resonant converter, and the second-stage open-loop DC-DC converter includes a switched-capacitor converter.

12. The power converter according to any one of the preceding claims, characterized in that, The first-stage regulated DC-DC converter includes a linear regulator, and the second-stage open-loop DC-DC converter includes a switched-capacitor voltage multiplier.

13. The power converter according to any one of the preceding claims, characterized in that, The first-stage regulated DC-DC converter includes a switch-mode converter, preferably a boost converter, and wherein the second-stage open-loop DC-DC converter includes a switched-capacitor voltage multiplier.

14. A method for converting an input DC voltage into an output DC voltage, characterized in that, The method includes the following steps: A power converter is provided, the power converter comprising: A first-stage regulated DC-DC converter, adapted to receive input DC power and generate an intermediate DC voltage; A second-stage open-loop DC-DC converter, adapted to receive the intermediate DC voltage from the first-stage regulated DC-DC converter and generate an output DC voltage; and The first-stage regulating DC-DC converter is controlled to adjust the intermediate DC voltage based on the measurement of the output DC voltage and the target output DC voltage, thereby also adjusting the output DC voltage.

15. The method according to claim 14, characterized in that, Use the power converter according to any one of claims 1 to 13.

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