Boost control circuit and control method based on current sampling

Abstract

The invention discloses a boost control circuit and control method based on current sampling, the boost control circuit comprises a boost conversion module, a current sampling module, a voltage sampling module and a control module, the input end of the current sampling module is connected with the current sampling end of the boost conversion module, and the output end of the current sampling module is connected with the first input end of the control module; the input end of the voltage sampling module is connected with the voltage output end of the boost conversion module, and the output end of the voltage sampling module is connected with the second input end of the control module; the output end of the control module is connected with the control end of the boost conversion module. According to the boost control circuit, through cooperative detection of the current sampling module and the voltage sampling module and in combination with a double-loop adjustment mechanism of the control module, the stability of a loop is improved, the control bandwidth is optimized, and therefore the situation that the dynamic performance is affected due to the stability requirement is avoided.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a boost control circuit and control method based on current sampling. Background Technology

[0002] With the continuous development of electronic technology, boost circuits are increasingly widely used in various electronic devices, especially playing a crucial role in portable devices and power management systems. However, existing boost circuits generally adopt voltage feedback control, which has certain drawbacks. Voltage feedback control relies on a single-loop structure, resulting in poor dynamic response performance and slow response speed. The fundamental reason is that the control loop is too sensitive to changes in output capacitor parameters and load. When the load changes abruptly, the output voltage is prone to large fluctuations, and the time required for the system to recover to a stable state is prolonged, seriously affecting the reliability of equipment operation.

[0003] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a boost control circuit and control method based on current sampling, which has the advantages of improving dynamic response performance, reducing output voltage fluctuations, and enhancing system stability.

[0005] The technical solution adopted in this invention is: a boost control circuit based on current sampling, comprising a boost converter module for boosting the input voltage to the output voltage, a current sampling module for detecting the current signal of the boost converter module, a voltage sampling module for detecting the output voltage, and a control module for controlling the output voltage to stabilize. The input terminal of the current sampling module is connected to the current sampling terminal of the boost converter module, and the output terminal of the current sampling module is connected to the first input terminal of the control module. The input terminal of the voltage sampling module is connected to the voltage output terminal of the boost converter module, and the output terminal of the voltage sampling module is connected to the second input terminal of the control module. The output terminal of the control module is connected to the control terminal of the boost converter module.

[0006] Furthermore, the boost converter module includes an inductor L1, a diode D1, and a MOSFET Q1. One end of the inductor L1 is connected to the input voltage, and the other end is connected to the anode of the diode D1 and the drain of the MOSFET Q1. The cathode of the diode D1 serves as the output terminal of the boost converter module and is connected to the input terminal of the voltage sampling module. The gate of the MOSFET Q1 is connected to the output terminal of the control module, and the source is connected to the input terminal of the current sampling module.

[0007] Furthermore, the current sampling module includes a first resistor R1 and a differential amplifier U1. One end of the first resistor is connected to the source of the MOS transistor Q1 and the positive input terminal of the differential amplifier U1, and the other end of the first resistor is connected to the negative input terminal of the differential amplifier U1 and ground. The output terminal of the differential amplifier U1 is connected to the first input terminal of the control module.

[0008] Furthermore, the voltage sampling module includes a second resistor R2, a third resistor R3, and a second comparator U2. One end of the second resistor R2 is connected to the output terminal of the boost converter module, and the other end is connected to one end of the third resistor R3 and the inverting input terminal of the second comparator U2. The other end of the third resistor R3 is grounded. The non-inverting input terminal of the second comparator U2 is connected to the reference power supply, and the output terminal of the second comparator U2 is connected to the second input terminal of the control module.

[0009] Furthermore, the control module includes a time base oscillator, a summation comparator, a third comparator U3, and a PWM flip-flop. The frequency adjustment terminal of the time base oscillator is grounded via a fourth resistor. The power supply terminal of the time base oscillator is connected to a fixed power supply. The output terminal of the time base oscillator is connected to the first input terminal of the summation comparator. The output terminal of the current sampling circuit is connected to the second input terminal of the summation comparator. The output terminal of the summation comparator and the output terminal of the voltage sampling module are respectively connected to the non-inverting and inverting input terminals of the third comparator U3. The output terminal of the third comparator U3 is connected to the input terminal of the PWM flip-flop. The output terminal of the PWM flip-flop is connected to the control terminal of the boost converter module.

[0010] Furthermore, the control module also includes a voltage comparator for stabilizing the input voltage, the input terminal of which is connected to the input voltage.

[0011] A control method for a boost control circuit based on current sampling, as described above, includes the following steps: The current sampling module detects the current signal from the boost converter module and converts it into a voltage signal; The voltage sampling module detects the output voltage and generates a voltage feedback signal; The time-base oscillator generates a periodic reference signal; The summation comparator generates a periodic modulation signal based on the voltage signal and the periodic reference signal; The third comparator U3 generates a square wave signal based on the periodic modulation signal and the voltage feedback signal; The PWM trigger generates a PWM drive signal based on the square wave signal; The duty cycle of the MOSFET in the boost converter module is controlled by the PWM drive signal to stabilize the output voltage.

[0012] Furthermore, when the output voltage is lower than the target voltage, the voltage feedback signal instructs the PWM trigger to reduce the duty cycle of the PWM drive signal, thereby increasing the output voltage.

[0013] Furthermore, when the output voltage is higher than the target voltage, the voltage feedback signal instructs the PWM trigger to increase the duty cycle of the PWM drive signal, thereby reducing the output voltage.

[0014] Furthermore, during the startup phase of the boost control circuit, a voltage comparator determines whether the input voltage is within the set operating range. If it is not within the set operating range, a protection action is performed.

[0015] The beneficial effects of this invention are as follows: This invention solves the problems of slow dynamic response, large output voltage fluctuation and insufficient stability in traditional voltage mode control by using the coordinated detection of current sampling module and voltage sampling module, combined with the dual-loop regulation mechanism of control module. It has the advantages of improving dynamic response performance, reducing output voltage fluctuation and enhancing system stability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the boost control circuit of the present invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0018] It should be understood that, when used in this application specification and the appended claims, terms include indicating the presence of a described feature, integral, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof; the terms first, second, third, etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] Furthermore, references to one or more embodiments described in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in connection with that embodiment. Therefore, statements appearing in different parts of this specification, such as in one embodiment, some embodiments, some other embodiments, and some still other embodiments, do not necessarily refer to the same embodiment, but rather mean one or more, but not all, embodiments, unless otherwise specifically emphasized.

[0020] like Figure 1As shown, this application proposes a boost control circuit based on current sampling, which includes a boost converter module for boosting the input voltage Vn to the output voltage Vo, a current sampling module for detecting the current signal of the boost converter module, a voltage sampling module for detecting the output voltage, and a control module for controlling the output voltage to stabilize. The input terminal of the current sampling module is connected to the current sampling terminal of the boost converter module, and the output terminal of the current sampling module is connected to the first input terminal of the control module; the input terminal of the voltage sampling module is connected to the voltage output terminal of the boost converter module, and the output terminal of the voltage sampling module is connected to the second input terminal of the control module; the output terminal of the control module is connected to the control terminal of the boost converter module.

[0021] The boost converter module converts a lower input voltage into a higher output voltage. It achieves voltage boosting through an energy storage and release mechanism and is the core part of the circuit to realize the boost function.

[0022] The current sampling module is used to monitor the current signal inside the boost converter module in real time. By accurately detecting the current signal, it can provide current feedback information to the control module, thereby achieving precise control of the circuit's operating state.

[0023] The voltage sampling module is used to detect the output voltage of the boost converter module. It converts the output voltage into an electrical signal that can be processed by the control module as a voltage feedback signal to ensure the stability of the output voltage.

[0024] The control module is the decision-making center of the entire boost control circuit. It receives feedback signals from the current sampling module and the voltage sampling module, and generates control signals according to the preset control strategy, thereby adjusting the working state of the boost conversion module to maintain the stability of the output voltage.

[0025] Specifically, in terms of circuit connection, the input terminal of the current sampling module is connected to the current sampling terminal of the boost converter module, ensuring that the current sampling module can directly obtain the current information inside the boost converter module, providing a data basis for subsequent current feedback control. The current signal detected by the current sampling module is effectively transmitted to the control module, serving as a key basis for the control module to perform inner loop adjustment.

[0026] The input terminal of the voltage sampling module is connected to the voltage output terminal of the boost converter module, enabling the voltage sampling module to monitor the actual output voltage of the boost converter module in real time and provide accurate voltage information for the voltage feedback loop. The voltage feedback signal generated by the voltage sampling module is sent to the control module, serving as another key basis for the control module to perform outer loop adjustment to stabilize the output voltage.

[0027] The output of the control module is connected to the control terminal of the boost converter module. This connection is the execution path of the control loop. The control module generates corresponding control commands based on the received current and voltage feedback signals, and adjusts the working state of the boost converter module through this connection, such as adjusting the switching duty cycle of the power devices, thereby stabilizing the output voltage.

[0028] The boost control circuit in this embodiment effectively solves the problems of insufficient dynamic response performance, slow response speed, large output voltage fluctuations, and limited loop stability in traditional single-loop voltage feedback control by introducing a dual feedback control mechanism of current sampling module and voltage sampling module. Therefore, when the load changes abruptly, the output voltage fluctuation is suppressed, the recovery time is shortened, and the loop stability is improved, resulting in optimized control bandwidth and avoiding the impact of stability requirements on dynamic performance.

[0029] In one embodiment, this application proposes a boost converter module including an inductor L1, a diode D1, and a MOSFET Q1. One end of the inductor L1 is connected to the input voltage, and the other end is connected to the anode of the diode D1 and the drain of the MOSFET Q1. The cathode of the diode D1 serves as the output terminal of the boost converter module and is connected to the input terminal of the voltage sampling module. The gate of the MOSFET Q1 is connected to the output terminal of the control module, and the source is connected to the input terminal of the current sampling module.

[0030] Specifically, the boost converter module is the core functional unit that enables the lower input voltage to be increased to a higher output voltage. Its basic working principle is to periodically charge and discharge the inductor, utilizing the inductor's energy storage characteristics to increase the voltage.

[0031] In the boost converter module, inductor L1 serves as an energy storage element. Its function is to store energy when the switching transistor is on and release the stored energy to the output terminal when the switching transistor is off, thereby boosting the voltage. The selection of inductor L1 requires consideration of parameters such as its inductance, saturation current, DC resistance, and core material to ensure that it does not saturate within the operating frequency and current range and has low losses. For example, a ferrite core inductor can be used to reduce high-frequency losses, or a powder core inductor can be used to improve the saturation current capability.

[0032] In the boost converter module, diode D1 primarily functions as a rectifyer and freewheeling diode, ensuring unidirectional current flow to the output and preventing reverse voltage generated by inductor L1 when the switching transistor is turned off from damaging other components. The characteristics of diode D1 directly affect conversion efficiency and output ripple. Common diode types include Schottky diodes, which have low forward voltage drop and fast recovery speed, making them suitable for high-frequency switching applications to reduce losses. MOSFET Q1, as the main switching element in the boost converter module, controls the charging and discharging of inductor L1 by periodically turning it on and off. The switching characteristics of MOSFET Q1 (such as on-resistance, switching speed, voltage withstand, and current capability) are crucial to the efficiency and dynamic response of the boost converter module. For example, a power MOSFET with low on-resistance can be selected to reduce conduction losses, or a MOSFET with lower gate charge can be selected to improve switching speed, thereby supporting higher switching frequencies.

[0033] Through the above technical solution, this application clearly defines the specific structure of the boost converter module as an inductor L1, a diode D1, and a MOSFET Q1, and specifies in detail their connection method, enabling the boost converter module to perform energy conversion efficiently. The coordinated operation of inductor L1 and MOSFET Q1 stores energy when MOSFET Q1 is on and releases energy when it is off, effectively reducing current ripple and improving energy conversion efficiency. Diode D1 ensures unidirectional current flow, preventing reverse current, and its cathode is directly connected to the input terminal of the voltage sampling module as the output terminal, ensuring accurate detection of the output voltage. The gate of MOSFET Q1 is connected to the output terminal of the control module, allowing the control module to adjust its switching state through precise PWM signals, thereby achieving precise control of the output voltage. Furthermore, the source of MOSFET Q1 is connected to the input of the current sampling module, enabling the circuit to acquire switching current information in real time. Combined with the feedback mechanism of the control module, current-mode control can be achieved, effectively improving the dynamic response speed and loop stability of the circuit. Especially when the load changes suddenly, the output voltage can be adjusted faster, reducing voltage fluctuations, thus solving the problems of slow dynamic response and poor stability of traditional voltage-mode control.

[0034] In one embodiment, this application further proposes a current sampling module, which includes a first resistor R1 and a differential amplifier U1. One end of the first resistor R1 is connected to the source of the MOSFET Q1 and the positive input terminal of the differential amplifier U1, and the other end of the first resistor R1 is connected to the negative input terminal of the differential amplifier U1 and ground. The output terminal of the differential amplifier U1 is connected to the first input terminal of the control module.

[0035] The first resistor R1 is a passive electronic component used to convert current signals into voltage signals. Its resistance is typically small to reduce power consumption and impact on the main circuit. In the current sampling module, the first resistor R1 primarily converts the current flowing through the source of the MOSFET Q1 into a voltage difference that can be detected by the differential amplifier U1. By measuring the voltage drop across this resistor, the current information flowing through the MOSFET Q1 can be indirectly obtained. In practical applications, the first resistor R1 can be a precision resistor with a low temperature coefficient and high stability to ensure consistent current sampling accuracy under different operating temperatures.

[0036] The differential amplifier U1 is an electronic amplifier capable of amplifying the voltage difference between two input terminals while suppressing common-mode voltages at both input terminals, exhibiting a high common-mode rejection ratio (CMRR). In the current sampling module, the differential amplifier U1 receives the small voltage difference across the first resistor R1 and amplifies it into a voltage signal recognizable by the control module. Simultaneously, it effectively suppresses common-mode interference such as power supply noise and ground noise, ensuring the purity of the current signal. The differential amplifier U1 can be configured as a differential amplifier using one or more general-purpose operational amplifiers through an external resistor network to provide flexible gain and bandwidth adjustment capabilities; alternatively, specially designed differential amplifier integrated circuits can be selected. These chips typically have higher CMRR, lower offset voltage, and wider bandwidth, making them suitable for high-precision current sampling applications.

[0037] Through the above technical solution, the first resistor R1 is directly connected in series in the source current path of the MOSFET Q1, converting the current flowing through the MOSFET Q1 into a small voltage difference. This voltage difference is fed into the positive and negative input terminals of the differential amplifier U1 for differential amplification. The differential amplifier U1 can effectively suppress common-mode noise that is prevalent in the power supply and ground lines, amplifying only the differential-mode signal representing the actual current. This design ensures high-fidelity transmission of the current signal and significantly reduces the impact of environmental noise and signal distortion on the accuracy of current detection. Therefore, the control module can receive a more accurate and pure current feedback signal, thereby responding to current changes more accurately and quickly, effectively improving the dynamic response performance of the entire boost control circuit, and enhancing the stability and reliability of the output voltage.

[0038] In one embodiment, this application further proposes an improved voltage sampling module, which includes a second resistor R2, a third resistor R3, and a second comparator U2. One end of the second resistor R2 is connected to the output of the boost converter module, and the other end is connected to one end of the third resistor R3 and the inverting input of the second comparator U2. The other end of the third resistor R3 is grounded. Meanwhile, the non-inverting input of the second comparator U2 is connected to a reference power supply, and the output of the second comparator U2 is connected to the second input of the control module.

[0039] Specifically, the second resistor R2 and the third resistor R3 together form a voltage divider network for accurately sampling the output voltage of the boost converter module. By appropriately selecting the resistance values ​​of the second resistor R2 and the third resistor R3, the higher output voltage can be proportionally attenuated to a voltage range suitable for the processing of the second comparator U2, thereby avoiding comparator input overload and ensuring the linearity and accuracy of the sampled signal. For example, high-precision metal film resistors or thin-film resistors can be used to reduce temperature drift and resistance error, and improve the stability of the voltage division ratio.

[0040] The function of the second comparator U2 is to compare the sampled voltage, after voltage division, with a stable reference power supply to generate a digital voltage feedback signal. When the sampled voltage is higher or lower than the reference voltage, the second comparator U2 can quickly toggle its output state, thus providing a fast-response voltage status indication. For example, the second comparator U2 can be a high-speed voltage comparator, such as the TLV3501, to ensure that a feedback signal can be generated promptly when there are small changes in the output voltage.

[0041] The reference power supply provides a stable reference voltage, such as 1.25V, for the second comparator U2, which is crucial for ensuring the accuracy of voltage sampling. A stable reference power supply ensures that the comparison threshold does not change with factors such as temperature and power supply voltage fluctuations, thus ensuring high consistency and reliability in the generation of the voltage feedback signal. When the output voltage is 20V, to ensure that the voltage between the second resistor R2 and the third resistor R3 is 1.25V, the second resistor R2 can be selected as 37.5K and the third resistor R3 as 2.5K. When the output voltage is below 20V, the voltage between the second resistor R2 and the third resistor R3 is below 1.25V, so U2 outputs a high level; when the output voltage is above 20V, the voltage between the second resistor R2 and the third resistor R3 is above 1.25V, so U2 outputs a low level.

[0042] Through the above technical solution, the voltage sampling module of this application utilizes a voltage divider network composed of the second resistor R2 and the third resistor R3 to accurately and proportionally attenuate the output voltage of the boost converter module, generating a stable sampling voltage. This sampling voltage is then sent to the inverting input of the second comparator U2 and compared in real time with the reference power supply connected to the non-inverting input. Because the second comparator U2 has a fast response characteristic, its output state will change rapidly once the output voltage deviates, generating a timely and accurate voltage feedback signal. This feedback signal is directly connected to the second input of the control module, enabling the control module to quickly sense changes in the output voltage and adjust the operating state of the boost converter module accordingly. This precise and fast voltage sampling mechanism solves the problems of insufficient accuracy and slow response that may exist in traditional voltage sampling, improving the stability of the control loop. In the event of sudden load changes or input voltage fluctuations, this voltage sampling module can quickly provide accurate feedback information, allowing the control module to adjust more quickly, effectively suppressing output voltage fluctuations, shortening recovery time, and thus improving the dynamic performance and output voltage stability of the entire boost control circuit.

[0043] In one embodiment, this application proposes a control module including a time base oscillator 1, a summation comparator 2, a third comparator U3, and a PWM trigger 3. The frequency adjustment terminal of the time base oscillator 1 is grounded through a fourth resistor R4. The power supply terminal of the time base oscillator 1 is connected to a fixed power supply. The output terminal of the time base oscillator 1 is connected to the first input terminal of the summation comparator. The output terminal of the current sampling circuit is connected to the second input terminal of the summation comparator 2. The output terminal of the summation comparator 2 and the output terminal of the voltage sampling module are respectively connected to the non-inverting and inverting input terminals of the third comparator U3. The output terminal of the third comparator U3 is connected to the input terminal of the PWM trigger 3. The output terminal of the PWM trigger 3 is connected to the control terminal of the boost converter module.

[0044] Specifically, a time-base oscillator is used to generate a periodic reference signal, such as a sawtooth wave or a triangular wave, as the time base for the control system. Its implementation can include, but is not limited to: an analog oscillator based on RC charging and discharging, where the oscillation frequency is set by adjusting the parameters of the resistor and capacitor; or a digital synthesizer (DDS) generating a precise digital waveform, which is then output as an analog signal via a digital-to-analog converter (DAC). This time-base oscillator provides a stable time reference for subsequent PWM modulation and is fundamental to achieving precise duty cycle control.

[0045] The summation comparator is used to superimpose the current sampling signal with a reference signal generated by the time-base oscillator. Specifically, it can be implemented using a summation circuit built with an operational amplifier (Op-amp) to linearly superimpose the current feedback signal and the reference signal, and then feed the superimposed signal into the comparator for comparison; alternatively, a dedicated analog signal processing chip can be used, which integrates summation and comparison functions and can efficiently process multiple analog signals. This summation comparator is a key component in constructing the current inner loop, used to incorporate current information into the PWM modulation process.

[0046] The third comparator U3 is used to compare the relative magnitudes of two input signals and output a high or low digital signal based on the comparison result. For example, it outputs a high level when the voltage at the non-inverting input is higher than the voltage at the inverting input, and a low level when they are lower. Its implementation can be, but is not limited to, using a high-speed operational amplifier configured in comparator mode to ensure fast response; or using a dedicated comparator integrated circuit, which typically has faster response speed and lower power consumption.

[0047] A PWM trigger is used to generate a pulse width modulation (PWM) signal with a corresponding duty cycle based on the input signal. This PWM signal is used to drive the power switching devices in the boost converter module, thereby regulating the output voltage. Its implementation can include, but is not limited to, using a dedicated driver chip, such as the low-side gate driver SGM48523 / 4A / 5 / 6, to drive the MOSFETs in the boost converter module.

[0048] The frequency adjustment terminal of the time base oscillator is grounded through a fourth resistor, designed to precisely set and stabilize the operating frequency of the time base oscillator. The resistance value of the fourth resistor determines the charging and discharging time constant of the oscillator, thus fixing the frequency of its output signal. This connection method ensures the stability and consistency of the oscillation frequency, avoiding frequency fluctuations caused by environmental changes or component drift, and providing a reliable time reference for the entire control system. The power supply terminal of the time base oscillator is connected to a fixed power supply, designed to provide a stable, noise-free DC operating voltage for the time base oscillator. A stable power supply can effectively suppress the influence of power supply ripple on the oscillation frequency and waveform accuracy, ensuring the accuracy and stability of the time base oscillator's output signal. The fixed power supply can be a low-voltage power supply for an external device, or the power supply corresponding to the input voltage of this application. In this case, the input voltage can be connected to the power supply terminal of the time base oscillator via a voltage comparator. The output terminal of the time base oscillator is connected to the first input terminal of a summing comparator, whose function is to introduce the periodic reference signal (e.g., a sawtooth wave) generated by the time base oscillator into the summing comparator. This reference signal, together with the current sampling signal, forms the modulation waveform of the inner current loop.

[0049] The output of the current sampling circuit is connected to the second input of the summation comparator, and its function is to feed back the actual current information of the boost converter module to the control module. Through this connection, the summation comparator can acquire the current signal in real time and process it with the reference signal of the time base oscillator to generate a modulation signal reflecting the current current state.

[0050] The outputs of the summation comparator and the voltage sampling module are connected to the non-inverting and inverting inputs of the third comparator U3, respectively, forming the error comparison stage of the voltage outer loop. The output of the summation comparator is typically a signal processed by the inner current loop (e.g., a current-modulated sawtooth wave), while the output of the voltage sampling module provides a feedback signal for the output voltage. The third comparator U3 compares these two signals to generate a square wave signal. The duty cycle of this square wave signal directly affects the output of the PWM trigger, thereby achieving precise regulation of the output voltage.

[0051] The output of the third comparator U3 is connected to the input of the PWM flip-flop. Its function is to transmit the error signal (usually a square wave or pulse signal) generated by the outer voltage loop to the PWM flip-flop. The PWM flip-flop outputs a PWM drive signal based on the characteristics of this input signal (e.g., pulse width or level). This connection ensures that the control decisions of the outer voltage loop can be effectively translated into the actual drive signal for the boost converter module.

[0052] The output of the PWM trigger is connected to the control terminal of the boost converter module. Its function is to directly apply the generated PWM drive signal to the power switching device (e.g., MOSFET) of the boost converter module. This PWM signal precisely regulates the energy transfer of the boost converter module by controlling the on and off times of the power switching device, thereby achieving stable control of the output voltage.

[0053] Through the above technical solution, the control module of this application adopts a dual-loop control mechanism of current inner loop and voltage outer loop, which solves the problems of poor dynamic response performance, slow response speed, large output voltage fluctuations during load changes, long recovery time, and poor stability of single-loop control. Specifically, a time base oscillator provides a stable time reference. The current sampling module detects the current signal of the boost converter module in real time and processes it with the reference signal generated by the time base oscillator in a summing comparator to form the modulation signal of the current inner loop. This current inner loop can respond quickly to current fluctuations caused by load changes, effectively suppressing current overshoot and undershoot, thereby improving the dynamic response speed and stability of the system. At the same time, the voltage sampling module detects the output voltage and generates a voltage feedback signal. This voltage feedback signal is compared with the output signal of the current inner loop in the third comparator U3 to form the error signal of the voltage outer loop. The PWM trigger generates a precise PWM drive signal based on this error signal, thereby controlling the duty cycle of the MOSFET in the boost converter module. This dual-loop control structure, especially the introduction of the inner current loop, enables the system to quickly track current changes and effectively suppress the limitation of control bandwidth by the right-half-plane zero point. This improves control bandwidth and dynamic performance while ensuring stability. During sudden load changes, the inner current loop can quickly adjust, limiting the rate of current change, reducing output voltage fluctuations, and shortening recovery time to ensure output voltage stability.

[0054] In one embodiment, this application further proposes that the control module also includes a voltage comparator 4 for stabilizing the input voltage, the input terminal of which is connected to the input voltage.

[0055] Specifically, the voltage comparator is an electronic device used to compare the magnitudes of two input voltages and output a corresponding level signal based on the comparison result. It can be implemented using an operational amplifier configured in comparator mode. For example, one input terminal is connected to the input voltage to be measured, and the other input terminal is connected to a preset reference voltage. When the input voltage exceeds the reference voltage, the output state flips. Alternatively, a dedicated voltage comparator integrated circuit, such as the LM393, can be used. These integrated circuits have advantages such as fast response speed and low power consumption, and can directly and quickly compare input voltages. The input terminals of the voltage comparator are connected to the input voltage, ensuring that the voltage comparator can directly and in real-time obtain the actual input voltage value of the circuit.

[0056] Through the above technical solution, this application introduces a voltage comparator into the control module and directly connects its input terminal to the input voltage, realizing real-time and direct monitoring of the input voltage. When the input voltage fluctuates or exceeds the preset normal operating range, the voltage comparator can quickly detect this abnormality and take timely measures, such as triggering a protection mechanism to cut off the power supply, preventing circuit damage due to abnormal input voltage. This design avoids unnecessary fluctuations in the output voltage when the input voltage changes, enhances the circuit's protection capability under abnormal input voltage conditions, and improves the stability and reliability of the entire boost control circuit.

[0057] In one embodiment, this application proposes a control method for the above-mentioned boost control circuit based on current sampling, the method comprising: The current sampling module detects the current signal from the boost converter module and converts it into a voltage signal; The voltage sampling module detects the output voltage and generates a voltage feedback signal; The time-base oscillator generates a periodic reference signal; The summation comparator generates a periodic modulation signal based on the voltage signal and the periodic reference signal; The third comparator U3 generates a square wave signal based on the periodic modulation signal and the voltage feedback signal; The PWM trigger generates a PWM drive signal based on the square wave signal; The duty cycle of the MOSFET in the boost converter module is controlled by the PWM drive signal to stabilize the output voltage.

[0058] Through the above technical solution, this application provides a control method for a boost control circuit based on current sampling. By integrating current and voltage feedback signals and combining sawtooth wave modulation and square wave generation, precise control of the PWM drive signal is achieved. The current sampling module detects the current signal from the boost conversion module and converts it into a voltage signal, making the current information easier to process in voltage form. This allows for rapid capture of current changes and provides immediate current feedback to the control loop. The voltage sampling module detects the output voltage and generates a voltage feedback signal, providing direct feedback on the output voltage for real-time adjustment. A time base oscillator generates a reference signal as a stable reference waveform, providing a time reference for the modulation process. A summation comparator generates a periodic modulation signal based on the voltage signal and the reference signal, combining the current feedback information with the reference signal to create a modulation signal containing current information, thereby enhancing the system's dynamic response capability. A third comparator U3 generates a square wave signal based on the periodic modulation signal and the voltage feedback signal. By comparing the modulation signal with the voltage feedback, a precise control signal is generated, ensuring loop stability and fast response. The PWM trigger generates a PWM drive signal based on the square wave signal to drive the MOSFET. Ultimately, the duty cycle of the MOSFET in the boost converter module is controlled by the PWM drive signal. By adjusting the switch duty cycle, the output voltage is directly stabilized, effectively dealing with load changes and input voltage fluctuations. This improves the dynamic response performance and loop stability of the boost control circuit, and reduces output voltage fluctuations and recovery time.

[0059] In one embodiment, this application further proposes a control method in which, when the output voltage is lower than the target voltage, the voltage feedback signal instructs the PWM trigger to reduce the duty cycle of the PWM drive signal, thereby increasing the output voltage.

[0060] Specifically, when the output voltage of the boost converter module is lower than the preset target voltage, the system triggers a corresponding control action. This condition of the output voltage being lower than the target voltage is determined by comparing the voltage feedback signal detected by the voltage sampling module with the preset target voltage. The specific control action is instructing the PWM trigger to reduce the duty cycle of the PWM drive signal, aiming to influence the output of the boost converter module by changing the characteristics of the PWM drive signal. When the voltage feedback signal indicates that the output voltage is low, the duty cycle of the square wave output by the third comparator U3 will decrease, thereby reducing the duty cycle of the PWM drive signal generated by the PWM trigger. The direct effect and purpose of this control action is to increase the output voltage, which is achieved by controlling the on-time (duty cycle) of the MOSFET Q1. When the duty cycle decreases, the on-time of the MOSFET Q1 shortens, and the time for the energy stored in the inductor L1 to be transferred to the output terminal in each cycle is relatively longer, thus increasing the output voltage.

[0061] Through the above technical solution, in the control method described above, the voltage sampling module continuously monitors the output voltage of the boost converter module and generates a voltage feedback signal. When the output voltage is detected to be lower than the preset target voltage, the voltage feedback signal sends a command to the PWM flip-flop after passing through the third comparator. Upon receiving this command, the PWM flip-flop correspondingly reduces the duty cycle of its generated PWM drive signal. The reduction in duty cycle directly affects the MOSFET Q1 in the boost converter module, shortening its conduction time, thereby increasing the output voltage. This fast response mechanism can effectively compensate for the output voltage drop caused by load changes or input voltage fluctuations, thus quickly pulling the output voltage back to the target range. This solution, through a clear duty cycle reduction strategy, improves the dynamic response speed of the system when the output voltage is low, shortens the voltage recovery time, and effectively suppresses output voltage fluctuations, thereby improving the stability and reliability of the boost control circuit based on current sampling.

[0062] In one embodiment, this application further proposes a control method in which, when the output voltage is higher than the target voltage, the voltage feedback signal instructs the PWM trigger to increase the duty cycle of the PWM drive signal, thereby reducing the output voltage.

[0063] Specifically, when the output voltage is detected to be higher than the preset target voltage, the voltage sampling module detects the output voltage and generates a corresponding voltage feedback signal. This voltage feedback signal is key information reflecting the current output voltage state. After being converted by U3, the voltage feedback signal is sent to the PWM flip-flop. The PWM flip-flop responsively adjusts its output PWM drive signal, increasing its duty cycle. By increasing the duty cycle of the PWM drive signal, the system can effectively reduce the energy transferred to the output terminal, thereby causing the excessively high output voltage to fall back to the target voltage range.

[0064] Through the above technical solution, when the output voltage exceeds the target voltage, the system can respond quickly by directly instructing the PWM trigger to increase the duty cycle of the PWM drive signal via a voltage feedback signal. This direct and rapid adjustment mechanism allows the boost converter module to promptly reduce the output voltage, avoiding prolonged fluctuations and recovery delays caused by excessively high voltage. Compared to traditional indirect adjustment methods, this solution can more effectively suppress output voltage overshoot, improve the system's dynamic response speed and stability, and ensure that the output voltage can be quickly and accurately stabilized near the target value.

[0065] In one embodiment, this application further proposes that during the startup phase of the boost control circuit, a voltage comparator is used to determine whether the input voltage is within the set operating range; if it is not within the set operating range, a protection action is performed.

[0066] A voltage comparator is an electronic device used to compare the magnitudes of two input voltages and output corresponding logic levels. Its function is to quickly and accurately detect whether the voltage has reached or exceeded a preset threshold.

[0067] Determining whether the input voltage is within the set operating range involves comparing the actual input voltage with a pre-set safe voltage range. This set operating range typically includes an upper threshold and a lower threshold to ensure that the input voltage is neither too high, causing device damage, nor too low, causing the circuit to fail to start or operate unstablely. A voltage comparator is used to compare the input voltage with a reference voltage representing these thresholds, thereby determining whether the input voltage is within the safe range.

[0068] Executing protective actions refers to the immediate measures taken by the system when an input voltage exceeds the set operating range to prevent further circuit damage or ensure operational safety. For example, the boost converter module can be immediately shut down by cutting off the drive signal to MOSFET Q1, thus protecting downstream circuitry. Another protective action can be issuing an alarm signal, such as illuminating an indicator light, triggering a buzzer, or sending an interrupt signal to the main controller, to alert the user or system to an anomaly. Furthermore, physical isolation can be achieved by disconnecting the input power supply from the boost circuit using a relay or power switch, or by adjusting circuit parameters to limit the current or voltage flowing through the circuit and keep it within a safe range.

[0069] With the above technical solution, when the input voltage deviates from the preset operating range, the voltage comparator can quickly detect this abnormality and immediately trigger the protection action, which can effectively avoid damage to the boost converter module or other circuit components caused by abnormal input voltage (such as overvoltage or undervoltage), and significantly improve the reliability and safety of the entire boost control circuit.

[0070] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application. Content not described in detail in this specification belongs to the prior art known to those skilled in the art.

Claims

1. A boost control circuit based on current sampling, characterized in that: The system includes a boost converter module for boosting the input voltage to the output voltage, a current sampling module for detecting the current signal of the boost converter module, a voltage sampling module for detecting the output voltage, and a control module for controlling the output voltage to stabilize. The input terminal of the current sampling module is connected to the current sampling terminal of the boost converter module, and the output terminal of the current sampling module is connected to the first input terminal of the control module. The input terminal of the voltage sampling module is connected to the voltage output terminal of the boost converter module, and the output terminal of the voltage sampling module is connected to the second input terminal of the control module. The output terminal of the control module is connected to the control terminal of the boost converter module.

2. The boost control circuit based on current sampling according to claim 1, characterized in that: The boost converter module includes an inductor L1, a diode D1, and a MOSFET Q1. One end of the inductor L1 is connected to the input voltage, and the other end is connected to the anode of the diode D1 and the drain of the MOSFET Q1. The cathode of the diode D1 serves as the output terminal of the boost converter module and is connected to the input terminal of the voltage sampling module. The gate of the MOSFET Q1 is connected to the output terminal of the control module, and the source is connected to the input terminal of the current sampling module.

3. The boost control circuit based on current sampling according to claim 1, characterized in that: The current sampling module includes a first resistor R1 and a differential amplifier U1. One end of the first resistor is connected to the source of the MOS transistor Q1 and the positive input terminal of the differential amplifier U1, and the other end of the first resistor is connected to the negative input terminal of the differential amplifier U1 and ground. The output terminal of the differential amplifier U1 is connected to the first input terminal of the control module.

4. The boost control circuit based on current sampling according to claim 1, characterized in that: The voltage sampling module includes a second resistor R2, a third resistor R3, and a second comparator U2. One end of the second resistor R2 is connected to the output of the boost converter module, and the other end is connected to one end of the third resistor R3 and the inverting input of the second comparator U2. The other end of the third resistor R3 is grounded. The non-inverting input of the second comparator U2 is connected to the reference power supply, and the output of the second comparator U2 is connected to the second input of the control module.

5. The boost control circuit based on current sampling according to claim 1, characterized in that: The control module includes a time base oscillator, a summation comparator, a third comparator U3, and a PWM flip-flop. The frequency adjustment terminal of the time base oscillator is grounded through a fourth resistor. The power supply terminal of the time base oscillator is connected to a fixed power supply. The output terminal of the time base oscillator is connected to the first input terminal of the summation comparator. The output terminal of the current sampling circuit is connected to the second input terminal of the summation comparator. The output terminal of the summation comparator and the output terminal of the voltage sampling module are respectively connected to the non-inverting and inverting input terminals of the third comparator U3. The output terminal of the third comparator U3 is connected to the input terminal of the PWM flip-flop. The output terminal of the PWM flip-flop is connected to the control terminal of the boost converter module.

6. The boost control circuit based on current sampling according to claim 1, characterized in that: The control module also includes a voltage comparator for stabilizing the input voltage, the input of which is connected to the input voltage.

7. A control method for a boost control circuit based on current sampling as described in claim 5, characterized in that: The current sampling module detects the current signal from the boost converter module and converts it into a voltage signal; The voltage sampling module detects the output voltage and generates a voltage feedback signal; The time-base oscillator generates a periodic reference signal; The summation comparator generates a periodic modulation signal based on the voltage signal and the periodic reference signal; The third comparator U3 generates a square wave signal based on the periodic modulation signal and the voltage feedback signal; The PWM trigger generates a PWM drive signal based on the square wave signal; The duty cycle of the MOSFET in the boost converter module is controlled by the PWM drive signal to stabilize the output voltage.

8. The control method according to claim 7, characterized in that: When the output voltage is lower than the target voltage, the voltage feedback signal instructs the PWM trigger to reduce the duty cycle of the PWM drive signal, thereby increasing the output voltage.

9. The control method according to claim 7, characterized in that: When the output voltage is higher than the target voltage, the voltage feedback signal instructs the PWM trigger to increase the duty cycle of the PWM drive signal, thereby reducing the output voltage.

10. The control method according to claim 7, characterized in that: It also includes using a voltage comparator to determine whether the input voltage is within the set operating range; if it is not within the set operating range, a protection action is performed.

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