Control device and method for an isolated converter, isolated converter

Abstract

The application discloses a control device and method of an isolated converter, and the isolated converter comprises a transformer and a primary switch tube. The control device comprises a secondary control circuit, an isolation module and a primary control circuit. The secondary control circuit is used for generating a data frame comprising a current limiting threshold value, the current limiting threshold value is used for controlling the primary switch tube to be turned off, a rising edge or a conduction position of a preset position of the data frame is used for controlling the primary switch tube to be turned on, and the rising edge or the conduction position of the preset position is located before the current limiting threshold value. The isolation module is used for transmitting the data frame from the secondary control circuit to the primary control circuit. The primary control circuit is used for receiving the data frame and controlling the primary switch tube according to the data frame. According to the application, the number of data transmission channels can be reduced, and the control response speed can be improved.

Description

Technical Field

[0001] This application relates to the field of switching power supplies, specifically to a control device and method for an isolation converter, and an isolation converter. Background Technology

[0002] In low-to-medium power supply systems requiring high reliability and dynamic performance, isolated converters such as flyback converters, forward converters, and LLC (Inductor-Inductor-Capacitor) resonant converters have become the mainstream choice for industrial control, medical equipment, new energy charging, and smart terminal power supply due to their electrical isolation characteristics. Traditionally, feedback control of isolated converters relies on optocouplers to transmit the secondary-side error signal back to the primary-side control circuit to control the primary-side switching action and achieve power transfer control. However, the electrical characteristics of optocouplers themselves result in high power consumption and limited bandwidth in this feedback control method. Therefore, digital isolation communication technology can be used to replace optocouplers with transient magnetic or electric field coupling to transmit feedback information, achieving more efficient feedback transmission.

[0003] However, existing digital isolation communication technologies require multiple isolation devices to transmit the turn-on and turn-off control information of the primary-side switching transistors separately, occupying multiple data transmission channels. Furthermore, the primary-side controller needs to decode the received turn-on and turn-off control information separately to obtain the turn-on and turn-off control information of the primary-side switching transistors. This approach is not only circuitically complex but also suffers from slow control response, low efficiency, and poor reliability. Summary of the Invention

[0004] This application provides a control device and method for an isolation converter, as well as an isolation converter, to solve the problems of large number of isolation channels, large transmission delay, and low efficiency in the prior art.

[0005] On one hand, embodiments of this application provide a control device for an isolation converter, the isolation converter including a transformer and a primary-side switch, and the control device including: a secondary-side control circuit, an isolation module, and a primary-side control circuit; The secondary-side control circuit is used to generate a data frame including a current limiting threshold. The current limiting threshold is used to control the primary-side switch to turn off. The rising edge or on bit of the data frame at a preset position is used to control the primary-side switch to turn on, and the rising edge or on bit at the preset position is located before the current limiting threshold. The isolation module is used to transmit the data frame from the secondary control circuit to the primary control circuit; The primary-side control circuit is used to receive the data frame and control the primary-side switching transistor according to the data frame.

[0006] Optionally, the rising edge of the preset position is the first rising edge of the data frame, or the on bit of the preset position is the first bit of the data frame.

[0007] Optionally, the data frame may further include at least one of fault information, mode information, and status information.

[0008] Optionally, the secondary control circuit includes an encoding module that performs encoding operations based at least on the enable signal and the current limiting threshold to generate the data frame.

[0009] Optionally, the secondary control circuit further includes: an analog-to-digital conversion module; An analog-to-digital converter module is used to convert the current limiting threshold into a digital signal and provide it to the encoding module.

[0010] Optionally, the primary-side control circuit includes: a decoding module, a digital-to-analog conversion module, and a PWM signal generation module; The decoding module is used to receive and decode the data frame and output the digital signals of the enable control signal and the current limiting threshold. The digital-to-analog converter module is used to convert the digital signal into an analog signal and output it to the PWM signal generation module; The PWM signal generation module is used to generate a PWM signal based on the turn-on control signal and the analog signal to control the primary-side switching transistor.

[0011] Optionally, the PWM signal generation module includes: a comparator and an RS flip-flop; The comparator receives the analog signal output by the digital-to-analog converter module at its first input terminal, receives the current detection signal flowing through the primary-side switching transistor at its second input terminal, and outputs a turn-off trigger signal at its output terminal. The RS flip-flop has its set terminal connected to the decoding module to receive the turn-on control signal, its reset terminal connected to the output terminal of the comparator to receive the turn-off trigger signal, and its output terminal outputting the PWM signal.

[0012] On the other hand, embodiments of this application also provide a control method for an isolation converter, the isolation converter including a transformer and a primary-side switch, the control method including: The transformer generates a data frame including a current limiting threshold. The current limiting threshold is used to control the primary-side switch to turn off. The rising edge or on bit of the data frame at a preset position is used to control the primary-side switch to turn on, and the rising edge or on bit of the preset position is located before the current limiting threshold. The data frame is transmitted from the secondary side of the transformer to the primary side of the transformer. The primary-side switching transistor of the transformer is controlled according to the data frame.

[0013] Optionally, the rising edge of the preset position is the first rising edge of the data frame, or the on bit of the preset position is the first bit of the data frame.

[0014] Optionally, the data frame may further include at least one of fault information, mode information, and status information.

[0015] Optionally, generating a data frame including a current limiting threshold on the secondary side of the transformer includes: performing an encoding operation based at least on the enable signal and the current limiting threshold to generate the data frame.

[0016] On the other hand, embodiments of this application also provide an isolation converter, the isolation converter including a control device for the isolation converter.

[0017] The control device and method for the isolation converter, and the isolation converter itself, provided in this application embodiment encode the enable signal and the current limiting threshold digitally in the same data frame for simultaneous transmission. Compared with existing solutions that require two independent isolation channels to transmit the enable signal and the current limiting threshold separately, the solution in this application embodiment reduces the number of data transmission channels, lowers system complexity and cost, and improves control response speed.

[0018] In this application, the data frame includes a current-limiting threshold for controlling the turn-off of the primary-side switch. The rising edge or on bit of the data frame at a preset position controls the turn-on of the primary-side switch, followed by the digital encoding of the current-limiting threshold. This data frame structure allows the primary-side control circuit to turn on the primary-side switch upon detecting the rising edge of the data frame and obtain the current-limiting threshold information for the current switching cycle in a very short time. This enables the current detection signal of the primary-side switch to be compared with the current-limiting threshold in a timely manner. When the current detection signal flowing through the primary-side switch reaches the current-limiting threshold, the primary-side switch is turned off promptly, thereby significantly reducing the response delay between turn-on and turn-off. While ensuring a fast turn-on response, it also ensures a fast turn-off control response, achieving dual fast control of the primary-side switch's turn-on and turn-off. This significantly improves the dynamic response speed of the control device and the real-time performance of the current-limiting protection.

[0019] Furthermore, system status information can be encoded into data frames, enabling the primary-side control module to perform functions such as rapid protection and coordinated control in case of faults, thereby improving system security and optimizing system efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application 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 only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the control device for the isolation converter provided in an embodiment of this application; Figure 2 This is a schematic diagram of a data frame structure in an embodiment of this application; Figure 3 This is a schematic diagram of another structure of the data frame in an embodiment of this application; Figure 4 This is another schematic diagram of the control device for the isolation converter provided in the embodiments of this application; Figure 5 This is another schematic diagram of the control device for the isolation converter provided in the embodiments of this application; Figure 6 This is another schematic diagram of the control device for the isolation converter provided in the embodiments of this application; Figure 7 This is a schematic diagram of a PWM signal generation module in an embodiment of this application; Figure 8 This is a flowchart of a control method for an isolation converter provided in an embodiment of this application; Figure 9 This is a flowchart illustrating the processing of a data frame sent by the secondary side after the primary side receives the data frame in an embodiment of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] To address the problems of complex circuits, long transmission delays, and low efficiency caused by the need for multiple isolation devices to separately transmit the on and off control information of the primary-side switch in existing technologies, this application provides a control device and method for an isolation converter, which simultaneously transmits the turn-on signal (whose time-domain interval implicitly contains the switching frequency information of the isolation converter) and the current limiting threshold digitally encoded in the same data frame.

[0024] It should be noted that, in this embodiment, the enable signal refers to an instruction signal used to instruct the primary-side switch to switch from its current state (usually the off state) to the on state. This signal can be a trigger signal dynamically generated based on the operating state of the isolation converter.

[0025] Specifically, the turn-on signal can be generated based on the output voltage Vo of the isolation converter and / or the control signal of the synchronous rectifier on the secondary side of the transformer. For example, when the output voltage Vo drops to a preset lower threshold, it indicates that the isolation converter needs to transfer energy from the primary side, and a turn-on signal is generated at this time; or, when the current of the synchronous rectifier is detected to cross zero, or when its control signal indicates that a switching cycle is about to end, a turn-on signal is generated to trigger the conduction of the primary-side switch in the next cycle.

[0026] In some embodiments, the turn-on signal can be dynamically generated in each switching cycle based on the output voltage Vo and the synchronous rectification state to ensure that the isolation converter achieves quasi-resonance or valley turn-on in discontinuous conduction mode (DCM) or critical conduction mode (CRM), thereby improving efficiency.

[0027] Unlike conventional enable signals used to start or stop the entire chip, the turn-on signal in this embodiment is a periodic, real-time control signal used to control the turn-on time of the primary-side switch in each switching cycle. The turn-on signal and the current limiting threshold together determine the turn-on timing and duration of the primary-side switch.

[0028] In this embodiment, the current limiting threshold is a state parameter whose value can be determined by the output voltage Vo, output load current, or other operating conditions. For example, in a non-limiting embodiment, the current limiting threshold can be continuously sampled and updated by the ADC, and the current current limiting threshold can be stored in a register; or the current current limiting threshold can be pre-calculated and prepared before the start of each switching cycle.

[0029] like Figure 1 The diagram shown is a structural schematic of a control device for an isolation converter provided in an embodiment of this application.

[0030] To clearly describe the control device 100, in Figure 1 The example is a flyback converter, which also shows the transformer T, the primary-side switch M1, and the secondary-side synchronous rectifier M2. Figure 1 The resistor R, capacitor C, and diode D in the circuit form an RCD absorption circuit.

[0031] Reference Figure 1 The control device 100 includes a secondary-side control circuit 101, an isolation module 102, and a primary-side control circuit 103. The primary-side control circuit 103 is responsible for controlling the on and off states of the primary-side switching transistor M1.

[0032] In this embodiment, the secondary control circuit 101 is used to generate a data frame including a current limiting threshold. The current limiting threshold is used to control the primary switch M1 to turn off. The rising edge or conduction bit at a preset position of the data frame is used to control the primary switch M1 to turn on, and the rising edge or conduction bit at the preset position is located before the current limiting threshold.

[0033] The isolation module 102 is used to transmit the data frame from the secondary control circuit 101 to the primary control circuit 103.

[0034] The primary-side control circuit 103 is used to receive data frames transmitted by the isolation module 102 and control the primary-side switching transistor M1 according to the data frames.

[0035] In some embodiments, the rising edge at the preset position is the first rising edge of the data frame, or the on bit at the preset position is the first bit of the data frame. This can minimize the turn-on transmission delay of the secondary-side control primary-side switch M1 and improve the response speed of the turn-on control (achieving nanosecond-level turn-on).

[0036] like Figure 2 The diagram shown is a structural schematic of a data frame in an embodiment of this application.

[0037] The data frame includes a current limiting threshold field. This field can be, for example, an N-bit digital code Primocp[N:0], used to indicate the current limiting threshold for the current switching cycle, where N is a positive integer. The data frame can control the primary-side switch M1 to turn on using the first rising edge, or an on bit can be added before the current limiting threshold field to control the primary-side switch M1 to turn on.

[0038] By sending a data frame containing the current limiting threshold in each switching cycle, cycle-by-cycle current limiting control of the primary-side switch M1 can be achieved. The initial default value of Primocp[N:0] can be set to the maximum allowed overcurrent protection threshold OCP on the primary side to ensure safety during system startup or communication anomalies.

[0039] In this way, the turn-on signal of the primary-side switch M1 (which determines the turn-on time of the primary-side switch M1, and thus the operating frequency of the converter) and the current-limiting threshold (which determines the turn-off time of the primary-side switch M1, and thus the peak current) are integrated into a single data frame and transmitted simultaneously. Accordingly, Figure 1Once the primary-side control circuit 103 detects a rising edge or on bit at a specific position in the data frame, it is equivalent to receiving an enable signal. This enables it to control the primary-side switch M1 to turn on, and then, based on the current-limiting threshold subsequently decoded, controls the primary-side switch M1 to turn off. Compared to the traditional approach that requires two independent isolated channels to transmit the enable signal and the current-limiting threshold separately, the solution in this application significantly reduces the number of data transmission channels, lowering system cost and complexity.

[0040] Those skilled in the art should understand that the turn-on signal in the embodiments of this application is a specific form of conduction control information used to indicate the turn-on time of the primary-side switch M1; the current limiting threshold is a specific form of turn-off control information used to limit the peak current of the primary-side switch M1. In other embodiments, the conduction control information may also be a conduction time command or a duty cycle command, and the turn-off control information may also be a turn-off time command or a fixed turn-off timing information, all of which should fall within the protection scope of this invention.

[0041] In some embodiments, Figure 1 The secondary-side control circuit 101 is also used to receive other system information and encode this system information into the data frame. In this way, more secondary-side information can be transmitted to the primary side without increasing the number of isolation channels.

[0042] The system information may include, but is not limited to, any one or more of the following: fault information, mode information, and status information. Accordingly, Figure 1 The primary-side control circuit 103 is also used to extract the system information from the data frame and perform corresponding control operations based on the system information, including: performing fault protection when receiving fault information, entering the corresponding control state when receiving mode information, or adjusting control parameters based on the state information.

[0043] like Figure 3 The diagram shown is a schematic diagram of another structure of the data frame in an embodiment of this application.

[0044] In this example, the data frame includes not only Figure 2 The current limiting threshold field in the code also includes one or more of the following signal fields: Fault information, Mode information, and State information. Among them: The Fault information is used to indicate whether a fault has occurred on the secondary side of the isolation converter, such as output open-loop protection, output overload protection, over-temperature protection, etc.

[0045] The Mode information is used to indicate the operating mode of the isolation converter, which may include, for example, Continuous On Mode (CCM), Intermittent On Mode (DCM), or Critical On Mode (CRM).

[0046] The State information is used to indicate whether the primary-side control circuit 103 enters a low-power state or a normal operating state, such as indicating that the primary-side control circuit 103 enters a low-power state under light load or no-load conditions.

[0047] It should be noted that, Figure 2 and Figure 3 The transmission order of the data frames can be flexibly selected according to the actual communication protocol used. If asynchronous serial transmission is used, such as UART (Universal Asynchronous Receiver / Transmitter), the LSB First (lowest byte first) transmission order is usually adopted; if synchronous serial transmission is used, such as SPI (Serial Peripheral Interface) or I2C (Inter-Integrated Circuit), the MSB First (most significant byte first) transmission order is usually adopted.

[0048] In a preferred embodiment of the present invention, an MSB First order is adopted, that is, the most significant bit (MSB) of the current limiting threshold field is transmitted first, and the least significant bit (LSB) is transmitted last. Those skilled in the art should understand that choosing the LSB First order can also achieve the technical solution of the present invention, and both fall within the protection scope of the present invention.

[0049] like Figure 4 As shown, in some embodiments, the secondary control circuit 101 includes an encoding module 111; the encoding module 111 performs an encoding operation based on the enable signal and the current limiting threshold to generate a data frame including the current limiting threshold.

[0050] Accordingly, the primary-side control circuit 103 is used to receive the data frame and perform decoding operation, control the primary-side switch M1 to turn on according to the decoded turn-on instruction, and control the primary-side switch M1 to turn off according to the decoded current limiting threshold.

[0051] like Figure 5 As shown, in some embodiments, the control device 100 may further include: an enable signal generation circuit 104 and a current limiting threshold providing circuit 105.

[0052] The turn-on signal generation circuit 104 is used to dynamically generate a turn-on signal based on at least one of the output voltage Vo of the isolation converter, the control signal of the synchronous rectifier switch M2, and the frequency signal of the internal oscillator; the turn-on signal is an edge-triggered signal used to indicate that the primary-side switch M1 should switch from the off state to the on state; and the turn-on signal is a periodic signal, the time interval between two adjacent turn-on signals determines the switching frequency of the isolation converter.

[0053] For example, in a non-limiting embodiment, the turn-on signal can be generated dynamically based on the frequency signal of the internal oscillator and the system state indicated by the output voltage Vo.

[0054] The current limiting threshold providing circuit 105 is used to provide a current limiting threshold; the current limiting threshold is a state parameter that varies with the output voltage Vo, used to limit the peak current flowing through the primary-side switch M1. For example, in constant voltage mode, as the output voltage Vo decreases, the current limiting threshold increases.

[0055] In some embodiments, the rate limiting threshold may be a numerical value.

[0056] like Figure 6 As shown, in some embodiments, the current limiting threshold can also be an analog voltage. In this case, the secondary control circuit 101 further includes an analog-to-digital converter 112 for converting the analog current limiting threshold into a digital signal and providing it to the encoding module 111.

[0057] Continue to refer to Figure 6 The primary-side control circuit 103 may include: a decoding module 131, a digital-to-analog conversion module 132, and a PWM signal generation module 133. Wherein: Decoding module 131 is used to receive and decode the data frame, obtain the digital codes of the enable indication and the current limiting threshold from the decoded data frame, output the enable control signal to the PWM signal generation module 133 according to the enable indication, and output the digital code of the current limiting threshold to the digital-to-analog converter module 132. The digital-to-analog converter module 132 is used to convert the digital encoding of the current limiting threshold into an analog current limiting threshold signal and output it to the PWM signal generation module 133; The PWM signal generation module 133 is used to generate a PWM signal based on the turn-on control signal and the analog current limiting threshold signal to control the turn-on and turn-off of the primary-side switch M1.

[0058] In the above embodiments, the isolation module 102 can specifically be a magnetic isolation module or a capacitive isolation module. Specifically, the data frame generated by the encoding module 111 is modulated onto a high-frequency carrier and transmitted to the primary side via magnetic or capacitive isolation. The received carrier signal is demodulated to recover the data frame.

[0059] Both isolation technologies mentioned above offer good timing stability, low transmission delay, and do not suffer from the aging issues associated with optocouplers. In practical implementation, the appropriate technology can be flexibly selected based on actual isolation withstand voltage, transmission rate, and power consumption requirements.

[0060] like Figure 7 The diagram shown is a structural schematic of a PWM signal generation module in an embodiment of this application.

[0061] Simultaneously refer to Figure 6 and Figure 7 In this embodiment, the PWM signal generation module 133 includes a comparator 1331 and an RS flip-flop 1332.

[0062] The first input terminal of the comparator 1331 receives the analog current limiting threshold signal output by the digital-to-analog converter module 132, the second input terminal receives the current detection signal flowing through the primary-side switch transistor M1, and its output terminal outputs a turn-off trigger signal. The set terminal S of the RS flip-flop 1332 is connected to the decoding module 131 to receive the turn-on control signal, the reset terminal R is connected to the output terminal of the comparator 1301 to receive the turn-off trigger signal, and the output terminal outputs the PWM signal.

[0063] The following is combined with Figure 6 and Figure 7 illustrate Figure 3 The data frame shown illustrates the generation, encoding, decoding of each field, and the primary edge's response to the system's state signals.

[0064] Figure 3 The data frame shown includes the rate limiting threshold Primocp[N:0], fault information Fault, mode information Mode, and state information State. Among them: Fault information can be generated by the secondary-side fault detection circuit (such as an overvoltage comparator, overtemperature sensor, etc.). When an output overvoltage, overcurrent, or overtemperature fault occurs on the secondary side, the fault status signal is set to valid, and the encoding module 111 encodes the fault information into the data frame. After decoding, the primary-side control circuit 103 can perform fault protection actions within the same switching cycle, such as shutting down the primary-side switch, to achieve rapid fault response.

[0065] The mode information (Mode) can be determined by both the output voltage and input voltage of the isolation converter. The encoding module 111 encodes this mode information into the data frame. After decoding, the primary-side control circuit 103 can adjust the control parameters accordingly, such as the switching frequency, current limiting threshold, or dead time, to adapt to different operating modes and optimize system efficiency.

[0066] When the isolation converter operates in CCM mode, the current in the primary inductor (magnetizing inductor) does not return to zero when the secondary-side synchronous rectifier M2 is turned off. At this time, if only the traditional cycle-by-cycle current limiting threshold is used for peak current comparison, the control loop is prone to generating subharmonic oscillations when the duty cycle exceeds 50%, leading to system instability.

[0067] To address this issue, in this embodiment, when the primary-side control circuit 103 identifies that it is currently in CCM mode, it can add ramp compensation based on the current limiting threshold and switch the maximum conduction time.

[0068] Specifically, the primary-side control circuit 103 superimposes a slope compensation signal with a slope proportional to the rate of decrease of the system inductor current on the received analog current limiting threshold. The compensated current limiting threshold is then compared with the real-time current detection signal of the primary-side switch M1, so that the equivalent duty cycle modulation no longer depends on the absolute current peak value, thereby eliminating the hidden danger of subharmonic oscillation and ensuring loop stability in CCM mode. In addition, since the transfer function of the converter is different in CCM mode than in DCM mode, and to avoid transformer core saturation due to sudden drops in input voltage or load changes, the primary-side control circuit 103 adopts a more stringent or adaptive maximum on-time limit based on the input voltage. For example, in CCM mode, it switches to a preset maximum on-time upper limit that matches the slope compensation slope, ensuring that even if a fault occurs that causes the current limiting comparator not to trigger, the primary-side switch M1 will be forcibly turned off when the maximum on-time is reached in each switching cycle, achieving dual protection.

[0069] In practical implementation, a slope compensation module and a maximum on-time control module can be set in the primary-side control module 103. When operating normally in DCM mode, the slope compensation module is either inactive or has a compensation value of zero by default. When the circuit enters CCM mode, the slope compensation module is activated, its input is connected to the output of the digital-to-analog converter module 132 to obtain the analog current limiting threshold Vth; its output outputs a current limiting threshold Vth_comp superimposed with the compensated slope. This compensated current limiting threshold Vth_comp is sent to the comparator 1331 of the PWM signal generation module 133 and compared with the detection signal representing the current of the primary-side switch M1. Simultaneously, the maximum on-time control module can select a preset on-time limit value Ton_max_CCM corresponding to the CCM mode based on the received CCM mode enable signal. If the comparator 1331 does not trigger the RS flip-flop 1332 to reset within the preset on-time limit value Ton_max_CCM, the timer generates a forced reset signal after reaching its timing time, turning off the primary-side switch M1.

[0070] With the above structure, the control circuit 100 of this application embodiment can achieve stable peak current control in CCM mode, while using the maximum on-time limitation to provide redundant protection for system safety.

[0071] The State information can be generated by the secondary-side output current detection module, and the encoding module 111 encodes this State information into a data frame. After receiving this signal, the primary-side control circuit 103 controls the isolation converter accordingly. For example, when the State information indicates a low-power state, the primary-side control circuit 103 controls the stop switch to operate and enters a sleep mode. After the output voltage drops, it resends the turn-on signal to wake up the converter, thereby effectively reducing power consumption.

[0072] The control device for the isolation converter provided in this application embodiment can simultaneously transmit the turn-on signal and the current limiting threshold using only one isolation channel, which not only reduces circuit complexity but also effectively improves control response speed. In particular, when the first rising edge or the first bit of the data frame is used as the turn-on indication, nanosecond-level turn-on response can be achieved. The current limiting threshold is transmitted digitally, which is more reliable than analog transmission. Furthermore, the current limiting threshold for each switching cycle can be dynamically adjusted according to the current output voltage, achieving precise overcurrent protection.

[0073] Accordingly, this application also provides an isolation converter, which includes the control device 100 for the isolation converter described above. The isolation converter can be any of the following: a flyback converter, a forward converter, or an LLC resonant converter.

[0074] Accordingly, embodiments of this application also provide a control method for an isolation converter, such as... Figure 8 The diagram shown is a flowchart of this control method, which includes the following steps: Step 801: A data frame including a current limiting threshold is generated on the secondary side of the transformer. The current limiting threshold is used to control the primary side switch to turn off. The rising edge or on bit of the data frame at a preset position is used to control the primary side switch to turn on, and the rising edge or on bit of the preset position is located before the current limiting threshold.

[0075] Specifically, the data frame is generated by encoding at least based on the enable signal and the current limiting threshold. The enable signal is an instruction signal used to instruct the primary-side switch to switch from its current state (usually the off state) to the on state. This signal can be a trigger signal dynamically generated based on the operating state of the isolation converter.

[0076] In some embodiments, the rising edge of the preset position can be the first rising edge of the data frame, or the turn-on bit of the preset position can be the first bit of the data frame, which can minimize the turn-on transmission delay of the secondary-side control primary-side switch M1 and improve the response speed of the turn-on control (achieving nanosecond-level turn-on).

[0077] In some embodiments, other system information, along with the aforementioned current limiting threshold, can be encoded into a data frame on the secondary side of the transformer, thereby transmitting more secondary-side information to the primary side without increasing the number of isolation channels. The system status information may include, but is not limited to, any one or more of the following: fault information, mode information, and status information.

[0078] Step 802: Transmit the data frame from the secondary side of the transformer to the primary side of the transformer.

[0079] Step 803: Control the primary-side switching transistor on the primary side of the transformer according to the data frame.

[0080] Specifically, the primary-side switch can be turned on according to the rising edge or turn-on bit of the preset position of the data frame, and the primary-side switch can be turned off according to the current limiting threshold in the data frame. The specific control method can be referred to the description in the previous embodiment of the control device of this application, and will not be repeated here.

[0081] When the data frame also carries other system information, the primary edge can perform corresponding operations after decoding to obtain the system status information.

[0082] Reference Figure 9 , Figure 9 The flowchart illustrates the processing steps after the primary edge receives the data frame sent by the secondary edge, when the data frame includes the aforementioned system information. In step 900, the primary side receives the data frame sent by the secondary side.

[0083] In step 901, the data frame is decoded, and the primary-side switch is immediately turned on when a rising edge or a conduction bit is detected.

[0084] On the one hand, in step 902, it is determined whether the sampled primary side current is greater than the current limiting threshold of the previous cycle transmission; if so, step 905 is executed; otherwise, step 903 is executed.

[0085] In step 903, the primary-side switch remains in the on state.

[0086] In step 904, it is further determined whether the sampled primary current is greater than the updated current limiting threshold; if so, step 905 is executed; otherwise, step 903 is executed.

[0087] Step 905: The primary-side switch is turned off. Then proceed to step 912.

[0088] On the other hand, in step 906, the data bits of the data frame are decoded.

[0089] In step 907, determine whether the rate limiting threshold decoding has been completed; if yes, then execute step 908 on one hand, otherwise return to step 906.

[0090] In step 908, the original edge current limiting threshold is updated.

[0091] In step 909, determine whether the system status information decoding has been completed. If yes, proceed to step 910; otherwise, return to step 906.

[0092] In step 910, perform the corresponding operation based on the system status.

[0093] In step 911, determine whether the primary-side switch is turned off; if so, proceed to step 912; otherwise, return to step 900.

[0094] In step 912, the primary edge updates the system status flag. Then return to step 900.

[0095] The control method for the isolation converter provided in this application transmits the enable signal and current limiting threshold encoded in the same data frame. The primary side controls the primary-side switch to turn on based on the rising edge or on bit of a preset position in the data frame, and controls the primary-side switch to turn off based on the current limiting threshold in the data frame. This allows for the isolation of multiple channels, achieving efficient transmission and response. Furthermore, the system information carried in the data frame enables the primary side to perform corresponding response operations based on the current system state, improving system performance.

[0096] In the description of the embodiments of this application, unless otherwise expressly specified and limited, ordinal numbers, such as "first" and "second," are used only to distinguish and describe related objects, and should not be construed as indicating or implying the relative importance or order between related objects. Furthermore, ordinal numbers do not represent the number of related objects.

[0097] In the description of the embodiments in this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. Other quantifiers are similar.

[0098] The terms "or" and "and / or" used in this application are used to describe the relationship between related objects, indicating a non-exclusive inclusion. For example, "A and / or B" can include: "A alone", "B alone", or "A with B". Additionally, the character " / " in this document indicates that the preceding and following related objects are in an "or" relationship.

[0099] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of modules is merely a logical functional division, and there may be other division methods in actual implementation, which this application does not limit.

[0100] In the embodiments of this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0101] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing unit, or they can be separate physical units, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware and software functional units.

[0102] Although embodiments of this application have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting this application. Any person skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments without departing from the spirit and scope of this application.

Claims

1. A control device for an isolation converter, the isolation converter comprising a transformer and a primary-side switching transistor, characterized in that, The control device includes: a secondary-side control circuit, an isolation module, and a primary-side control circuit; The secondary-side control circuit is used to generate a data frame including a current limiting threshold. The current limiting threshold is used to control the primary-side switch to turn off. The rising edge or on bit of the data frame at a preset position is used to control the primary-side switch to turn on, and the rising edge or on bit at the preset position is located before the current limiting threshold. The isolation module is used to transmit the data frame from the secondary control circuit to the primary control circuit; The primary-side control circuit is used to receive the data frame and control the primary-side switching transistor according to the data frame.

2. The control device for the isolation converter according to claim 1, characterized in that, The rising edge of the preset position is the first rising edge of the data frame, or the on bit of the preset position is the first bit of the data frame.

3. The control device for the isolation converter according to claim 1, characterized in that, The data frame also includes at least one of fault information, mode information, and status information.

4. The control device for the isolation converter according to any one of claims 1 to 3, characterized in that, The secondary control circuit includes an encoding module that performs encoding operations based at least on the enable signal and the current limiting threshold to generate the data frame.

5. The control device for the isolation converter according to claim 4, characterized in that, The secondary control circuit further includes: an analog-to-digital conversion module; An analog-to-digital converter module is used to convert the current limiting threshold into a digital signal and provide it to the encoding module.

6. The control device for the isolation converter according to claim 5, characterized in that, The primary-side control circuit includes: a decoding module, a digital-to-analog conversion module, and a PWM signal generation module; The decoding module is used to receive and decode the data frame and output the digital signals of the enable control signal and the current limiting threshold. The digital-to-analog converter module is used to convert the digital signal into an analog signal and output it to the PWM signal generation module; The PWM signal generation module is used to generate a PWM signal based on the turn-on control signal and the analog signal to control the primary-side switching transistor.

7. The control device for the isolation converter according to claim 6, characterized in that, The PWM signal generation module includes: a comparator and an RS flip-flop; The comparator receives the analog signal output by the digital-to-analog converter module at its first input terminal, receives the current detection signal flowing through the primary-side switching transistor at its second input terminal, and outputs a turn-off trigger signal at its output terminal. The RS flip-flop has its set terminal connected to the decoding module to receive the turn-on control signal, its reset terminal connected to the output terminal of the comparator to receive the turn-off trigger signal, and its output terminal outputting the PWM signal.

8. A control method for an isolation converter, the isolation converter comprising a transformer and a primary-side switch, characterized in that, The control method includes: A data frame including a current limiting threshold is generated on the secondary side of the transformer. The current limiting threshold is used to control the primary side switch to turn off. The rising edge or on bit of the data frame at a preset position is used to control the primary side switch to turn on, and the rising edge or on bit at the preset position is located before the current limiting threshold. The data frame is transmitted from the secondary side of the transformer to the primary side of the transformer. The primary-side switching transistor of the transformer is controlled according to the data frame.

9. The control method for the isolation converter according to claim 8, characterized in that, The rising edge of the preset position is the first rising edge of the data frame, or the on bit of the preset position is the first bit of the data frame.

10. The control method for the isolation converter according to claim 8, characterized in that, The data frame also includes at least one of fault information, mode information, and status information.

11. The control method for the isolation converter according to any one of claims 8 to 10, characterized in that, The process of generating a data frame including a current-limiting threshold on the secondary side of the transformer includes: The data frame is generated by encoding operations based at least on the enable signal and the current limiting threshold.

12. An isolation converter, characterized in that, The isolation converter includes a control device for the isolation converter as described in any one of claims 1 to 7.

Images