Power supply system based on Sigma-Delta modulation and adaptive calibration

Abstract

The invention discloses a power supply system based on Sigma-Delta modulation and adaptive calibration, which belongs to the field of signal processing and comprises a signal modulation path and an adaptive calibration path. The signal modulation path comprises a first Sigma-Delta ADC, an MOS switch tube and a line equivalent filter, and modulates an input voltage into an output voltage for power supply. The self-adaptive calibration path comprises a programmable gain amplifier, a second Sigma-Delta ADC, a compensation filter and a pre-stored lookup table, wherein the programmable gain amplifier is used for sampling output voltage. And after compensation filtering, comparing with ideal calibration parameters in the lookup table, and dynamically feeding back a generated error signal to a reference voltage end of the ADC to carry out real-time closed-loop calibration. Through cooperation of Sigma-Delta modulation and adaptive calibration, output ripples are reduced, errors caused by nonlinearity and path loss of components are effectively compensated, and the method is suitable for supplying power to complex scenes.

Description

Technical Field

[0001] This application relates to the field of signal processing, and more particularly to a power supply system based on Sigma-Delta modulation and adaptive calibration. Background Technology

[0002] Traditional switching power supplies mostly use PWM (Pulse Width Modulation) technology. PWM modulation generates discrete spectral components centered on the switching frequency and its harmonics, resulting in significant electromagnetic interference and output voltage ripple, making it difficult to meet the requirements of application scenarios with extremely high power purity.

[0003] Sigma-Delta modulation, due to its oversampling and noise shaping characteristics, can shape quantization noise within the baseband to the high-frequency region, thereby achieving an extremely high signal-to-noise ratio within the baseband. In recent years, research has attempted to apply Σ-Δ modulation to power conversion to replace traditional PWM, achieving a smoother output spectrum and lower in-band noise. However, the performance of existing Σ-Δ power conversion systems is significantly affected by analog component parameter drift, temperature variations, and power stage nonlinearities, lacking effective online compensation mechanisms, resulting in limited long-term stability and accuracy. Furthermore, there is a trade-off between the system's dynamic response speed and stability, making it difficult to achieve optimal performance over a wide load range.

[0004] In the invention patent with patent number CN 105048809 A, a DC-DC converter is proposed. Although it uses Sigma-Delta ADC instead of PWM for modulation, it still relies on a phase lead compensation network with fixed parameters. Specifically, it is composed of a first operational amplifier OP1, resistors R1 and R2 and capacitor Cc. This fixed compensation method cannot adapt to changes in dynamic operating conditions. When the input voltage fluctuates or the ambient temperature changes, or when remote cable power is supplied, the fixed compensation network cannot optimize the loop parameters in real time.

[0005] Therefore, there is an urgent need for a power supply system that can adapt to complex application scenarios by adaptively calibrating the voltage signal. Summary of the Invention

[0006] To address the shortcomings of existing technologies and the problem that current voltages cannot dynamically adapt to load changes, this application provides a power supply system based on Sigma-Delta modulation and adaptive calibration, including: a signal modulation path for modulating the input voltage into an output voltage for power supply; wherein the signal modulation path includes:

[0007] The first Sigma-Delta ADC receives the input voltage at its input terminal and outputs a 1-bit modulated signal; the driving unit is specifically a MOS switch, the input terminal of which is connected to the output terminal of the first Sigma-Delta ADC and is driven by the 1-bit modulated signal; the first filtering unit is specifically a cable equivalent filter, the input terminal of which is connected to the output terminal of the MOS switch and is used to filter the switching signal to generate the output voltage;

[0008] An adaptive calibration path, coupled to the signal modulation path, is used to sample the output voltage and perform adaptive calibration; the adaptive calibration path includes:

[0009] A programmable gain amplifier (PGA) samples the output voltage at its input to adjust the output voltage gain. A second Sigma-Delta ADC connects to the output of the PGA and outputs both a 1-bit and a multi-bit digital signal. A compensation filter connects to the multi-bit output of the second Sigma-Delta ADC to filter the multi-bit digital signal and obtain a compensation signal. A lookup table connects to the output of the compensation filter and stores ideal calibration parameters for different operating states. The compensation signal output from the compensation filter is compared with the ideal calibration parameters in the lookup table to generate an error signal. The output of the lookup table connects to the reference voltage adjustment terminal of the second Sigma-Delta ADC, dynamically adjusting the reference voltage based on the error signal to achieve real-time closed-loop calibration of the power supply system.

[0010] The beneficial effects of this application are:

[0011] 1. Unlike traditional fixed-frequency PWM modulation, this invention uses a Sigma-Delta ADC to generate control signals in the signal modulation path. By utilizing oversampling and noise shaping techniques, the equivalent filter in the subsequent circuit can more effectively filter out high-frequency noise, thereby achieving a lower in-band output ripple voltage than the traditional PWM scheme with the same filter complexity.

[0012] 2. The calibration process adapts to different load characteristics, cable conditions, or performance requirements without requiring modification of the analog hardware, greatly enhancing the system's adaptability and configurability.

[0013] 3. The collaborative architecture of the signal modulation path and the adaptive calibration path achieves global ripple suppression. The Sigma-Delta modulation of the signal modulation path optimizes the noise distribution, facilitating filtering; the adaptive calibration path corrects the system's nonlinearity and errors. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0015] Figure 1 This is a schematic diagram of a power supply system structure based on Sigma-Delta modulation and adaptive calibration.

[0016] The above figures include the following reference numerals:

[0017] 1- First Sigma-Delta ADC (Analog-to-Digital Converter), 2- MOS (Metal-Oxide-Semiconductor) switch, 3- RC filter (Resistance-Capacitance), 4- PGA (Programmable Gain Amplifier), 5- Second Sigma-Delta ADC, 6- sinc filter, 7- Lookup table. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort should fall within the scope of protection of the present application.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] This solution aims to address the problems of concentrated harmonics and high noise in traditional PWM power supplies. By introducing Sigma-Delta noise shaping technology and a digital adaptive calibration loop, it achieves high-precision and compensated voltage output. Figure 1 The diagram shows a power supply system structure based on Sigma-Delta modulation and adaptive calibration, specifically including a signal modulation path and an adaptive calibration path.

[0021] The signal modulation path includes a first Sigma-Delta ADC 1, a MOS switch 2, and an RC filter 3, which are mainly used to modulate the input voltage to generate a precise output voltage for power supply.

[0022] The first Sigma-Delta ADC receives the input voltage V. in It converts the signal into a high-speed 1-bit digital stream. Unlike the fixed duty cycle method of PWM, Sigma-Delta modulation pushes the energy of quantization noise to a high-frequency region much higher than the baseband through oversampling and noise shaping, resulting in extremely low noise in the low-frequency band and outputting a 1-bit modulated signal of "0" and "1".

[0023] The MOS switch is directly driven by a 1-bit modulated signal. Its gate is connected to the output of the first Sigma-Delta ADC through a gate driver. The function of the driver is to convert the 1-bit digital signal into a drive voltage to turn the MOS switch on / off, thereby controlling the power supply.

[0024] The line equivalent filter is a passive filter designed with a combination of inductors, capacitors and resistors. In this application, it is specifically an RC filter, which is physically a cable. Its main function is to demodulate the 1-bit modulated signal output by the MOS switch into a smooth DC voltage Vout for power supply, and to filter out high-frequency switching noise and quantization noise that has been shaped to the high frequency, thereby significantly reducing the output voltage ripple.

[0025] Due to factors such as load requirements, remote power supply via cables, and external influences, the DC voltage output through the signal modulation circuit will experience some loss. This system uses an adaptive calibration path for dynamic adaptive calibration to ensure that it can output accurate and stable voltage over a long period of time under various operating conditions. Specifically, it includes a programmable gain amplifier 4, a second Sigma-Delta ADC 5, a compensation filter 6, and a lookup table 7.

[0026] In this embodiment, the programmable gain amplifier is specifically a PGA, which can dynamically adjust the gain of the signal to ensure that the amplitude of the sampled output voltage Vout is always within the optimal quantization range of the ADC, thereby maximizing the dynamic range, signal-to-noise ratio and measurement accuracy of the entire monitoring channel.

[0027] The second Sigma-Delta ADC converts the optimal amplitude analog voltage output from the PGA into a digital signal and outputs two digital signals: one is a 1-bit digital signal, and the other is a multi-bit digital signal. The multi-bit digital signal is processed by the compensation filter inside the second Sigma-Delta ADC, specifically a sinc filter in this application. This filter can remove out-of-band noise, digitally average and downsample the high-speed bitstream inside the ADC, and output an extremely stable, high-resolution digital value representing the accurate measurement result of Vout. The sinc filter works in conjunction with the RC filter in the signal modulation path. The RC filter performs initial smoothing in the analog domain, while the sinc filter performs final precise definition and compensation in the digital domain.

[0028] In this embodiment, a look-up table (LUT) is pre-set, storing the ideal calibration parameters that the measurement results should have under known operating conditions (different reference voltages, different loads, and different temperatures). The look-up table receives the output after filtering by a sinc filter and compares the actual output value with the stored ideal calibration parameters to calculate the error signal. The current error signal represents the system performance deviation caused by temperature drift, component aging, load nonlinearity, etc. The reference voltage of the second Sigma-Delta ADC is adjusted based on the negative feedback of the error signal, forming a real-time precision negative feedback calibration loop to ensure that the output always approximates the ideal characteristics.

[0029] In summary, this system reduces output voltage ripple through Sigma-Delta modulation and subsequent lookup table comparison adaptive calibration, enabling loss compensation for remote power supply and making it suitable for power supply scenarios in various environments.

[0030] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0031] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0032] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0033] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0034] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A power supply system based on Sigma-Delta modulation and adaptive calibration, characterized in that, include: The signal modulation path is used to modulate the input voltage into an output voltage for power supply. The signal modulation path includes: The first Sigma-Delta ADC receives the input voltage at its input terminal and is used to output a 1-bit modulated signal; The driving unit is specifically a MOS switch, the input terminal of which is connected to the output terminal of the first Sigma-Delta ADC and is driven by the 1-bit modulation signal; The first filtering unit is specifically a cable equivalent filter. The input terminal of the cable equivalent filter is connected to the output terminal of the MOS switch, and is used to filter the switching signal to generate the output voltage. An adaptive calibration path, coupled to the signal modulation path, is used to sample the output voltage and perform adaptive calibration. The adaptive calibration path includes: A programmable gain amplifier, wherein the input terminal of the programmable gain amplifier samples the output voltage to adjust the gain of the output voltage; The second Sigma-Delta ADC, whose input is connected to the output of the programmable gain amplifier, is used to output two digital signals: a 1-bit digital signal and a multi-bit digital signal. A compensation filter, the input of which is connected to the multi-bit digital signal output of the second Sigma-Delta ADC, is used to filter the multi-bit digital signal to obtain a compensation signal; A lookup table is provided, with its input connected to the output of the compensation filter. The lookup table stores ideal calibration parameters for different operating states in advance. The compensation signal output by the compensation filter is compared with the ideal calibration parameters in the lookup table to generate an error signal. The output of the lookup table is connected to the reference voltage adjustment terminal of the second Sigma-Delta ADC. The reference voltage is dynamically adjusted according to the error signal to achieve real-time closed-loop calibration of the power supply system.

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