Overcurrent protection device, converter control device, and electronic device

Abstract

The application provides an overcurrent protection device, a converter control device and an electronic device. The overcurrent protection device comprises a load current determination module, a reference difference value determination module and an overcurrent protection determination module. The load current determination module is configured to determine a first load current of a converter according to an input voltage of the converter and a clamping capacitor voltage of the converter. The reference difference value determination module is configured to determine a reference difference value of the converter according to the first load current and a reference current. The overcurrent protection determination module is configured to determine a closed-loop reference voltage of the converter according to the reference difference value of the converter, and determine whether to output an overcurrent protection signal. The closed-loop reference voltage is used to adjust an output voltage of the converter, and the overcurrent protection signal is used to perform overcurrent protection on the converter. Compared with the table lookup method in the prior art for determining the overcurrent protection signal, the overcurrent protection system accuracy and reliability of the converter can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of converter technology, and more particularly to an overcurrent protection device, a converter control device, and an electronic device. Background Technology

[0002] Dual-clamp zero-voltage switching converters (referred to as converters in this application) are widely used in applications with a wide input-output range. Figure 1 This is a schematic diagram of the structure of a dual-clamp zero-voltage switching converter in the prior art, such as... Figure 1 As shown, the dual-clamp zero-voltage switching converter includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, and a fifth switch Q5, as well as a power transformer T and V. in V is the input voltage of the converter. c Clamping capacitor C f The voltage. The converter has four operating modes in one switching cycle: input energy storage stage, primary-secondary side energy transfer stage, resonant stage, and freewheeling stage. Figure 2 This is a timing diagram of a dual-clamp zero-voltage switching converter in the prior art, such as... Figure 2 As shown, during the input energy storage stage (T1), the first switch Q1 and the fourth switch Q4 are turned on, and the input voltage V in Applied to the primary side of the transformer, during this stage, the leakage inductance L r And excitation inductance L m Energy storage; during the primary-secondary energy transfer phase (T2), the first switch Q1 and the fourth switch Q4 are off, while the second switch Q2, the third switch Q3, and the fifth switch Q5 are on. Energy is transferred from the primary side to the secondary side of the power transformer T, and the primary voltage of the power transformer T is clamped by the secondary output voltage. During the resonance phase, the first switch Q1, the third switch Q3, the fourth switch Q4, and the fifth switch Q5 are off, while the second switch Q2 is on. At this time, the magnetizing inductor L... m Leakage inductance L r The parasitic capacitances of the third switch Q3, the fourth switch Q4, and the fifth switch Q5 resonate. During the freewheeling phase, the first switch Q1, the third switch Q3, and the fifth switch Q5 are turned off, while the second switch Q2 and the fourth switch Q4 are turned on. The primary voltage of the power transformer T is clamped to zero. During this phase, the primary side of the power transformer T no longer transfers energy to the secondary side. Figure 2 The duration of T3 is the sum of the duration of the resonance phase and the duration of the freewheeling phase.

[0003] In existing technologies, to achieve overcurrent protection for converters, tables are typically used to record the converter's current at different input voltages V. in Below, the load current i of the converter oWhen the overcurrent threshold is reached, the output signal v of the error amplifier in the converter err Then, the output signal v of the error amplifier in the converter was detected in multiple consecutive interruptions. err When the current exceeds the overcurrent threshold in the table, it is determined to be an overcurrent protection signal (OCP), thereby realizing overcurrent protection for the converter.

[0004] However, in the existing technology, the method of determining the overcurrent protection signal by looking up a table and then protecting the converter from overcurrent requires frequent testing of the converter, and the accuracy of the overcurrent protection signal depends on the size of the table data. There may be a large deviation in the unrecorded data, resulting in low reliability. Summary of the Invention

[0005] This application provides an overcurrent protection device, a converter control device, and an electronic device, which can effectively improve the reliability of the overcurrent protection signal of the converter.

[0006] In a first aspect, embodiments of this application provide an overcurrent protection device, comprising:

[0007] Load current determination module, reference difference determination module, and overcurrent protection determination module.

[0008] The output of the load current determination module is connected to the input of the reference difference determination module, the output of the reference difference determination module is connected to the input of the overcurrent protection determination module, and the output of the overcurrent protection determination module is connected to the control module of the converter.

[0009] The load current determination module is used to determine the first load current of the converter based on the input voltage of the converter and the clamping capacitor voltage of the converter.

[0010] The reference difference determination module is used to determine the reference difference of the converter based on the first load current and the reference current;

[0011] The overcurrent protection determination module is used to determine the converter's closed-loop reference voltage based on the converter's reference difference, and to determine whether to output an overcurrent protection signal. The closed-loop reference voltage is used to adjust the converter's output voltage, and the overcurrent protection signal is used to provide overcurrent protection for the converter.

[0012] In one possible implementation, the overcurrent protection device provided in this application embodiment includes a load current determination module specifically used to determine a first load current according to the following formula:

[0013]

[0014] Among them, i oc This represents the first load current, K represents the proportional coefficient, and f sT represents the operating frequency of the converter. on V represents the excitation duration of the converter. in V represents the input voltage of the converter. c This indicates the clamping capacitor voltage of the converter.

[0015] In one possible implementation, the overcurrent protection device provided in this application embodiment includes a reference difference determination module comprising a limiting module and a proportional amplification module. The input terminal of the limiting module is connected to the output terminal of the load current determination module, the output terminal of the limiting module is connected to the input terminal of the proportional amplification module, and the output terminal of the proportional amplification module is connected to the input terminal of the overcurrent protection determination module.

[0016] The limiting module is specifically used to determine the current difference between the first load current and the reference current, and to determine the difference current using the current difference.

[0017] The proportional amplifier module is used to amplify the differential current according to a preset ratio to obtain a reference difference value.

[0018] In one possible implementation, the overcurrent protection device provided in this application determines the differential current using the current difference, including:

[0019] When the current difference is greater than zero, the difference current is determined to be the same as the current difference.

[0020] When the current difference is less than or equal to zero, the difference current is determined to be zero.

[0021] In one possible implementation, the overcurrent protection device provided in this application embodiment includes an overcurrent protection determination module comprising an update module, an overload voltage reduction module, and a comparison module.

[0022] The input terminal of the update module is connected to the output terminal of the reference difference determination module, the output terminal of the update module is connected to the input terminal of the overload step-down module, the output terminal of the overload step-down module is connected to the input terminal of the comparison module and the control module of the converter, and the output terminal of the comparison module is connected to the control module of the converter.

[0023] The update module is used to perform step updates on the reference difference, determine the reference change amount in each step cycle, and then adjust the closed-loop reference voltage in each step cycle.

[0024] The overload step-down module is used to determine the final closed-loop reference voltage of the converter based on the reference change determined by the update module.

[0025] The comparison module is used to determine the overcurrent protection signal of the converter based on the final closed-loop reference voltage and the undervoltage reference voltage of the converter.

[0026] In one possible implementation, the overcurrent protection device provided in this application further includes a low-frequency clock and a high-frequency clock. The low-frequency clock is used to control the working cycle of the load current determination module, and the high-frequency clock is used to control the working cycle of the update module.

[0027] In one possible implementation, the overcurrent protection device provided in this application embodiment includes a comparison module specifically used for:

[0028] The final closed-loop reference voltage is compared with the undervoltage reference voltage, and an overcurrent protection signal is output when the final closed-loop reference voltage is less than the undervoltage reference voltage.

[0029] Secondly, embodiments of this application provide a converter control device, including: a converter control module and an overcurrent protection device as provided in the first aspect and optional embodiments of the first aspect.

[0030] In one possible implementation, the converter control device provided in this application includes a control module comprising: an error amplification module, a period calculation module, and a control signal generation module. The error amplification module is used to determine an error amplification signal based on the sampled value of the clamping capacitor voltage of the converter and the final closed-loop reference voltage.

[0031] The cycle calculation module is used to determine the operating duration of each working mode within the switching cycle of the converter based on the error amplification signal and the clamping capacitor voltage;

[0032] The control signal generation module is used to output the switching control signal of the converter based on the operating duration of each working mode within the switching cycle of the converter and the overcurrent protection signal.

[0033] In one possible implementation, the converter control device provided in this application embodiment further includes a periodic timer, which is used to determine the switching period of the converter.

[0034] Thirdly, embodiments of this application provide an electronic device, including an overcurrent protection device as provided in the first aspect and optional embodiments of the first aspect, the contents of which can be referred to the first aspect; or, including a converter control device as provided in the second aspect and optional embodiments of the second aspect, the contents of which can be referred to the second aspect, and will not be repeated here.

[0035] This application provides an overcurrent protection device, a converter control device, and an electronic device. The overcurrent protection device includes: a load current determination module, a reference difference determination module, and an overcurrent protection determination module. The output terminal of the load current determination module is connected to the input terminal of the reference difference determination module, the output terminal of the reference difference determination module is connected to the input terminal of the overcurrent protection determination module, and the output terminal of the overcurrent protection determination module is connected to the control module of the converter. The load current determination module is used to determine a first load current of the converter based on the input voltage and the clamping capacitor voltage of the converter. The reference difference determination module is used to determine a reference difference of the converter based on the first load current and a reference current. The overcurrent protection determination module is used to determine a closed-loop reference voltage of the converter based on the reference difference of the converter, and to determine whether to output an overcurrent protection signal. The closed-loop reference voltage is used to adjust the output voltage of the converter, and the overcurrent protection signal is used to provide overcurrent protection for the converter. By determining the first load current of the converter based on the input voltage and the clamping capacitor voltage of the converter, and then determining the reference difference between the first load current and the reference current, the closed-loop reference voltage and overcurrent protection signal of the converter are determined based on the reference difference. Compared with the table lookup method used in the prior art to determine the overcurrent protection signal, the reliability of the overcurrent protection signal of the converter can be effectively improved. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of a dual-clamp zero-voltage switching converter in the prior art;

[0038] Figure 2 This is a timing diagram of the operation of a dual-clamp zero-voltage switching converter in the prior art;

[0039] Figure 3 This is a schematic diagram of the overcurrent protection device provided in one embodiment of this application;

[0040] Figure 4 A schematic diagram of the overcurrent protection device provided in another embodiment of this application;

[0041] Figure 5 This is a schematic diagram of a step-up update provided in an embodiment of this application;

[0042] Figure 6 This is a schematic diagram of the converter control device provided in the embodiments of this application;

[0043] Figures 7-9 This is a schematic diagram illustrating the effect of an exemplary overcurrent protection provided in the embodiments of this application;

[0044] Figure 10 This is a schematic diagram illustrating the effect of overcurrent protection in existing technologies. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a 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.

[0047] In existing technologies, to achieve overcurrent protection for converters, tables are typically used to record the converter's current at different input voltages V. in Below, the load current i of the converter o When the overcurrent threshold is reached, the output signal v of the error amplifier in the converter err Then, the output signal v of the error amplifier in the converter is detected at multiple consecutive terminals. err When the current exceeds the overcurrent threshold in the table, it is identified as an overcurrent protection (OCP) signal, thereby protecting the converter from overcurrent. However, existing methods require frequent testing of the converter, and the accuracy of the overcurrent protection signal depends on the size of the table data; there may be significant deviations in areas where no data is recorded, resulting in low reliability.

[0048] To address the aforementioned technical problems, the inventive concept of the overcurrent protection device, converter control device, and electronic device provided in this application embodiment lies in determining the first load current of the converter based on the input voltage and clamping capacitor voltage of the converter, and then determining the reference difference value of the converter based on the first load current and the reference current; finally, determining the final closed-loop reference voltage and overcurrent protection signal of the converter based on the reference difference value. Compared with the table lookup method used in the prior art to determine the overcurrent protection signal, this method can effectively improve the overload performance and reliability of the converter.

[0049] The overcurrent protection device, converter control device, and electronic equipment provided in the embodiments of this application will be described below.

[0050] Figure 3 This is a schematic diagram of the overcurrent protection device provided in one embodiment of this application, as shown below. Figure 3 As shown, the overcurrent protection device provided in this application embodiment may include: a load current determination module, a reference difference determination module, and an overcurrent protection determination module.

[0051] Specifically, the output of the load current determination module is connected to the input of the reference difference determination module, the output of the reference difference determination module is connected to the input of the overcurrent protection determination module, and the output of the overcurrent protection determination module is connected to the control module of the converter.

[0052] The load current determination module is used to determine the current based on the input voltage V of the converter. in and the clamping capacitor voltage v of the converter c Determine the first load current i of the converter. oc The reference difference determination module is used to determine the reference difference based on the first load current i. oc With reference current i om Determine the reference difference value ΔV of the converter. ref The overcurrent protection determination module is used to determine the converter's reference difference value ΔV. ref Determine the final closed-loop reference voltage V of the converter. ref Then, based on the final closed-loop reference voltage V ref and the set undervoltage reference voltage V UVP Determine the overcurrent protection signal OCP.

[0053] This application embodiment describes how to determine the input voltage V of the converter. in and the clamping capacitor voltage v of the converter c Determine the first load current i of the converter. oc The specific implementation method is not limited; for example, the input voltage V of the converter can be obtained from the register. in and the clamping capacitor voltage v of the converter cThen, the first load current i of the converter can be determined through software. oc The embodiments described in this application are merely examples and are not limited thereto.

[0054] In one possible implementation, the overcurrent protection device provided in this application embodiment includes a load current determination module specifically used to determine a first load current according to the following formula:

[0055]

[0056] Among them, i oc This represents the first load current, K represents the proportional coefficient, and f s T represents the operating frequency of the converter. on V represents the excitation duration of the converter. in V represents the input voltage of the converter. c This indicates the clamping capacitor voltage of the converter.

[0057] The reasoning process for the above formula is shown in Formula 2-8: According to the law of conservation of energy,

[0058]

[0059]

[0060]

[0061] P o =V o i oc (5)

[0062] P tran η = P o (6)

[0063]

[0064]

[0065] Among them, L m L represents the magnetizing inductance of the converter. r V represents the leakage inductance of the converter. in W represents the input voltage of the converter. peak L represents the single-cycle magnetizing inductance of the converter. m Energy storage, i peak T represents the magnetizing inductor current at the end of phase T1 of the converter. on P represents the excitation duration of the converter, which is equivalent to the duration of T1. tran f represents the power transferred from the primary side to the secondary side of the converter during stage T2. s k represents the operating frequency of the converter.t P represents the primary-to-secondary turns ratio of the converter. o V represents the output power of the converter. o i represents the output voltage of the converter. oc η represents the first load current of the converter, η represents the transmission efficiency from the primary side to the secondary side of the converter, and K is the proportional coefficient, which is approximately a constant.

[0066] The principle behind the above formula is explained as follows: During the interval between the freewheeling phase and the input energy storage phase, the freewheeling current charges the parasitic capacitance of the second switch Q2, and releases the parasitic capacitance of the first switch Q1. At the beginning of the input energy storage phase, the magnetizing inductance L of the converter... m and leakage L r Almost all of the stored energy is transferred to the parasitic capacitance of the second switch Q2 and the input source of the converter front end. At this time, the energy flows through the converter magnetizing inductor L. m The current is approximately zero. Therefore, the magnetizing inductance L during the energy storage stage is... m The stored energy is approximately equal to the peak stored energy at the end of the input energy storage phase, at which point the energy flowing through the magnetizing inductor L... m The peak current is i peak Peak current i peak The magnitude is determined by the input voltage V in Input energy storage phase duration T on Magnetizing inductance L m and leakage L r And determines the power P transferred from the primary side to the secondary side. tran Equals the energy transferred in a single cycle multiplied by the operating switching frequency f s In each switching cycle, the energy transferred from the primary side to the secondary side during the primary-to-secondary energy transfer phase is approximately equal to the energy transferred from the primary side to the secondary side during the input energy storage phase by the magnetizing inductor L. m Energy storage W peak As is known from the background technology, the clamping capacitor voltage v at the end of the primary-secondary energy transfer phase can be sampled. c The value divided by the transformer primary and secondary turns ratio k t To characterize the output voltage V o Therefore, V in the substitution formula o Then simplify and combine the transmission efficiency η and the magnetizing inductance L. m and leakage L r Turns ratio k t The constant term is a constant K. In the formula, the operating frequency f... s Input energy storage phase duration T on This is a quantity necessary for controlling the on-time of the first switch Q1 and the second switch Q2 in the digital controller, and it can be read directly from the register. Simultaneously, the digital controller needs to sample the input voltage V. in Clamping capacitor voltage v cInformation such as voltage V is used for protection and closed-loop feedback, so the input voltage V in and clamping capacitor voltage sampling value V c It can also be obtained directly from the register. The scaling factor K can be freely defined according to the required range of calculated values.

[0067] In addition, this application embodiment does not impose specific limitations on the working cycle of the load current determination module. In one possible implementation, the overcurrent protection device provided in this application embodiment may also include a low-frequency clock Clk2 for controlling the working cycle of the load current determination module.

[0068] After determining the first load current of the converter, the first load current is input to the reference difference determination module. The reference difference determination module determines the reference difference of the converter based on the first load current and the reference current. This application embodiment does not limit the specific structure of the reference difference determination module; for example, it can be implemented in software or hardware.

[0069] In one possible implementation, Figure 4 This is a schematic diagram of the overcurrent protection device provided in another embodiment of this application, as shown below. Figure 4 As shown, the reference difference determination module includes a limiting module and a proportional amplification module. The input terminal of the limiting module is connected to the output terminal of the load current determination module, the output terminal of the limiting module is connected to the input terminal of the proportional amplification module, and the output terminal of the proportional amplification module is connected to the input terminal of the overcurrent protection determination module.

[0070] The limiting module is specifically used to determine the first load current i. oc With reference current i om The current difference i dif And using the current difference i dif Determine the differential current i d The proportional amplifier module is used to amplify the differential current i d The value is magnified according to a preset ratio to obtain the reference difference ΔV. ref .

[0071] In one possible implementation, the overcurrent protection device provided in this application determines the differential current using the current difference, including: when the current difference is greater than zero, determining that the differential current is the same as the current difference; and when the current difference is less than or equal to zero, determining that the differential current is zero. In another possible implementation, a current difference threshold can also be set; when the current difference is greater than the current difference threshold, determining that the differential current is the same as the current difference; and when the current difference is less than or equal to the current difference threshold, determining that the differential current is zero.

[0072] After determining the difference current, the difference current is amplified by a proportional amplification module according to a preset ratio. In this embodiment of the application, the specific value of the preset ratio is not limited. For example, it can be amplified by 2 times, 5 times, 10 times, etc., to obtain the reference difference value.

[0073] In another possible implementation, the reference difference determination module may not include the proportional amplification module, but only the limiting module, and the difference current is used as the reference difference. This application embodiment is only an example and is not limited thereto.

[0074] In one possible implementation, such as Figure 4 As shown in the embodiment of this application, the overcurrent protection device, the overcurrent protection determination module may include an update module, an overload step-down module and a comparison module.

[0075] The input of the update module is connected to the output of the reference difference determination module. The output of the update module is connected to the input of the overload step-down module. The output of the overload step-down module is connected to the input of the comparison module and the control module of the converter. The output of the comparison module is connected to the control module of the converter.

[0076] The update module is used to update the baseline difference ΔV. ref Perform step updates and determine the baseline change v for each step cycle. step The overload step-down module is used to adjust the voltage based on the reference change v in each step cycle. step Determine the final closed-loop reference voltage V. ref The comparison module is used to compare the final closed-loop reference voltage V. ref With the undervoltage reference voltage V of the converter UVP Determine the overcurrent protection signal of the converter.

[0077] The embodiments of this application do not limit the stepping cycle of the update module. In one possible implementation, the overcurrent protection device provided in the embodiments of this application further includes a high-frequency clock Clk1, which is used to control the working cycle of the update module.

[0078] In this embodiment, as shown in the figure above, the load current determination module determines the first load current of the converter based on the low-frequency clock Clk2, and the update module updates the reference change amount of the reference difference based on the high-frequency clock Clk1. This is because the load current calculation is time-consuming. For high-frequency converters, fast interrupts based on high-frequency clocks often handle loop calculations, PWM pulse width calculations, etc. Placing the time-consuming load current calculation in a fast interrupt would compress the frequency of the fast interrupt and reduce the system's response speed. If the update module is based on the low-frequency clock Clk2, updating a large reference change amount at once when the load current changes abruptly can easily cause system instability. Limiting the single update step size would make the system react too slowly to sudden changes. Therefore, the load current calculation and the reference difference calculation are placed in a low-speed interrupt based on the low-frequency clock, and the reference change amount is updated with a fixed step size in a fast interrupt based on the high-frequency clock.

[0079] Figure 5 This is a schematic diagram of a step-up update provided in an embodiment of this application, as shown below. Figure 5 As shown, ΔV ref The waveform is the reference difference calculated based on the load current change during the low-speed interrupt, v step The waveform is a fast interrupt that follows ΔV cycle by cycle with a fixed step size. ref The change in the baseline.

[0080] Determine the baseline change v for each step cycle. step Subsequently, the overload buck module of the overcurrent protection device provided in this application embodiment generates the final closed-loop reference voltage V of the converter. ref On the one hand, the overload buck module will ultimately close the loop reference voltage V. ref The input to the control module of the converter, specifically, is the final closed-loop reference voltage V. ref The input is given to the error amplification module of the converter, so that the error amplification module can calculate the sampled value v of the clamping capacitor voltage of the converter. c * and the final closed-loop reference voltage V ref Determine the error amplification signal v err On the other hand, the overload buck module will ultimately close the loop reference voltage V. ref The input is sent to the comparator module, and the comparator module converts the final closed-loop reference voltage V into a voltage. ref With the undervoltage reference voltage V of the converter UVP The overcurrent protection signal of the converter is determined. This application does not limit the specific implementation of the comparison module; it can be implemented in software or hardware. In one possible implementation, the comparison module can be implemented using a comparator, for example, by comparing the closed-loop reference voltage V... ref The input is given to the non-inverting input of the comparator, which converts the undervoltage reference voltage V of the converter.UVP The input is given to the inverting input of the comparator, when the final closed-loop reference voltage V... ref Greater than the undervoltage reference voltage V of the converter UVP When the comparator outputs a high level, it outputs an overcurrent protection signal; when the final closed-loop reference voltage V... ref Less than the undervoltage reference voltage V of the converter UVP When the comparator outputs a low level, it does not output an overcurrent protection signal. This embodiment is merely an example and is not limited to this. For instance, the above function can be achieved by combining a comparator with gate circuits, or by software control.

[0081] In addition, the embodiments of this application specify the undervoltage reference voltage V of the converter. UVP There are no restrictions on the specific values; they can be set according to the actual situation.

[0082] In one possible implementation, the overcurrent protection device provided in this application embodiment includes a comparison module specifically used for:

[0083] The final closed-loop reference voltage is compared with the undervoltage reference voltage, and an overcurrent protection signal is output when the final closed-loop reference voltage is less than the undervoltage reference voltage.

[0084] The overcurrent protection device provided in this application determines the first load current of the converter based on the input voltage and the clamping capacitor voltage of the converter. Then, it determines the reference difference between the first load current and a reference current. Finally, based on the reference difference, it determines the final closed-loop reference voltage of the converter. A comparison module then compares the final closed-loop reference voltage with an undervoltage reference voltage. When the final closed-loop reference voltage is less than the undervoltage reference voltage, it outputs an overcurrent protection signal to the converter's control module. Upon receiving the overcurrent protection signal, the converter's control module shuts down the converter, thus achieving overcurrent protection. In another possible implementation, the comparison module is also used to prevent the output of the overcurrent protection signal when the final closed-loop reference voltage is greater than or equal to the reference voltage, ensuring the normal operation of the converter. Compared to the lookup table method used in the prior art to determine the overcurrent protection signal, this method effectively improves the overload performance and reliability of the converter.

[0085] This application also provides a converter control device, including: a converter control module and an overcurrent protection device as provided in the above embodiments.

[0086] In one possible implementation, Figure 6 This is a schematic diagram of the converter control device provided in the embodiments of this application, as shown below. Figure 6As shown in the embodiment of this application, the converter control device includes a control module comprising: an error amplification module, a period calculation module, and a control signal generation module. The error amplification module is used to calculate the period based on the sampled value v of the converter's clamping capacitor voltage. c * and the final closed-loop reference voltage V ref Determine the error amplification signal v err The period calculation module is used to calculate the period based on the error amplification signal v. err and clamping capacitor voltage v c The operating duration (T1 / T2 / T3) of each working mode within the switching cycle of the converter is determined. The control signal generation module is used to determine the switching control signal of the converter based on the operating duration of each working mode within the switching cycle of the converter and the overcurrent protection signal OCP. When the overcurrent protection signal OCP is high, the control signal S1 of the converter will be low, the first switching transistor Q1 will be turned off, and the converter will disconnect from the input power supply.

[0087] The error amplification module may include a proportional element K. v v c * Indicates the clamping capacitor voltage v c After the proportional process K v The sampled value is then used to calculate the sampled value v of the clamping capacitor voltage. c * and the final closed-loop reference voltage V ref The difference is used to obtain v. e Finally, through an error amplifier, v e The present application embodiment does not limit the specific structure of the error amplifier or the amplification factor for proportional-integral amplification.

[0088] In one possible implementation, the converter control device provided in this application embodiment further includes a periodic timer, which is used to determine the switching period of the converter, wherein S R This is the start signal for the converter cycle. In one possible implementation, the converter control device provided in this application embodiment may further include a clock module, which includes a crystal oscillator, a frequency multiplier, and a frequency divider, for determining the high-frequency clock Clk1 and the low-frequency clock Clk2.

[0089] Figures 7-10 This is a schematic diagram illustrating the effect of exemplary overcurrent protection provided in the embodiments of this application, such as... Figure 7As shown, with input voltages of 16V, 28V, and 50V, and first load currents of 11.75A, 11.7A, and 11.65A respectively, the converter enters overload buck operation. The output voltage decreases with increasing load, exhibiting a drooping characteristic. Overcurrent protection signals are generated at first load currents of 14.25A, 14.15A, and 14.4A, and the converter shuts down. Figure 8 As shown, from the point of overload until the converter's output voltage drops to the undervoltage point, the converter can operate stably at all load points; such as Figure 9 As shown, when the converter slowly de-loads after overload, each load point can operate stably. Figure 10 This is a schematic diagram illustrating the effect of overcurrent protection in existing technologies, in comparison. Figure 7 and 10 Therefore, the device provided in this application embodiment has a significantly reduced overload restart voltage and reduced losses during overload.

[0090] This application also provides an electronic device, including an overcurrent protection device or converter control device as provided in the embodiments of this application. The content and effects are the same as those in the above embodiments and will not be repeated here.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An overcurrent protection device, characterized in that, include: Load current determination module, reference difference determination module, and overcurrent protection determination module. The output terminal of the load current determination module is connected to the input terminal of the reference difference determination module, the output terminal of the reference difference determination module is connected to the input terminal of the overcurrent protection determination module, and the output terminal of the overcurrent protection determination module is connected to the control module of the converter. The load current determination module is used to determine the first load current of the converter based on the input voltage of the converter and the clamping capacitor voltage of the converter; The reference difference determination module is used to determine the reference difference of the converter based on the first load current and the reference current; The overcurrent protection determination module is used to determine the closed-loop reference voltage of the converter based on the reference difference of the converter, and to determine whether to output an overcurrent protection signal. The closed-loop reference voltage is used to adjust the output voltage of the converter, and the overcurrent protection signal is used to provide overcurrent protection for the converter. The load current determination module is specifically used to determine the first load current according to the following formula: Wherein, i oc The first load current is represented by K, the proportionality coefficient is represented by f. s The T represents the operating frequency of the converter. on The V represents the excitation duration of the converter. in The input voltage of the converter is represented by v. c This represents the clamping capacitor voltage of the converter.

2. The apparatus according to claim 1, characterized in that, The reference difference determination module includes a limiting module and a proportional amplification module. The input terminal of the limiting module is connected to the output terminal of the load current determination module, the output terminal of the limiting module is connected to the input terminal of the proportional amplification module, and the output terminal of the proportional amplification module is connected to the input terminal of the overcurrent protection determination module. The limiting module is specifically used to determine the current difference between the first load current and the reference current, and to determine the difference current using the current difference. The proportional amplification module is used to amplify the difference current according to a preset ratio to obtain the reference difference value.

3. The apparatus according to claim 2, characterized in that, The step of determining the difference current using the current difference includes: When the current difference is greater than zero, it is determined that the difference current is the same as the current difference. When the current difference is less than or equal to zero, the difference current is determined to be zero.

4. The apparatus according to any one of claims 1-3, characterized in that, The overcurrent protection determination module includes an update module, an overload voltage reduction module, and a comparison module; The input terminal of the update module is connected to the output terminal of the reference difference determination module, the output terminal of the update module is connected to the input terminal of the overload step-down module, the output terminal of the overload step-down module is connected to the input terminal of the comparison module and the control module of the converter, and the output terminal of the comparison module is connected to the control module of the converter. The update module is used to update the reference difference in steps and determine the reference change amount in each step cycle. The overload buck module is used to determine the final closed-loop reference voltage of the converter based on the reference change amount determined by the update module. The comparison module is used to determine the overcurrent protection signal of the converter based on the final closed-loop reference voltage and the undervoltage reference voltage of the converter.

5. The apparatus according to claim 4, characterized in that, It also includes a low-frequency clock and a high-frequency clock, wherein the low-frequency clock is used to control the working cycle of the load current determination module, and the high-frequency clock is used to control the working cycle of the update module.

6. The apparatus according to claim 4, characterized in that, The comparison module is specifically used to: compare the final closed-loop reference voltage with the undervoltage reference voltage, and output the overcurrent protection signal when the final closed-loop reference voltage is less than the undervoltage reference voltage.

7. A converter control device, characterized in that, include: The converter's control module and the overcurrent protection device as described in any one of claims 1-6.

8. The apparatus according to claim 7, characterized in that, The control module includes an error amplification module, a period calculation module, and a control signal generation module. The error amplification module is used to determine the error amplification signal based on the sampled value of the clamping capacitor voltage of the converter and the final closed-loop reference voltage. The cycle calculation module is used to determine the operating duration of each working mode within the switching cycle of the converter based on the error amplification signal and the clamping capacitor voltage. The control signal generation module is used to output the switching control signal of the converter according to the working duration of each working mode within the switching cycle of the converter and the overcurrent protection signal.

9. The apparatus according to claim 8, characterized in that, It also includes a periodic timer, which is used to determine the switching period of the converter.

10. An electronic device, characterized in that, Includes the apparatus as described in any one of claims 1-9.

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