Diode peak current suppression circuit

Abstract

This application relates to a diode spike current suppression circuit, comprising: a first switching unit, a current sampling unit, an impedance switching module, and a switching control module; the first switching unit, the current sampling unit, and the impedance switching module are connected in series, and this series line is connected in parallel with the diode being protected; the first output terminal of the switching control module is connected to the control terminal of the first switching unit, and is used to adjust the current flowing through the first switching unit; the second and third output terminals of the switching control module are respectively connected to the impedance switching module, and are used to adjust the impedance of the impedance switching module. The solution of this application adjusts the current flowing through the first switching unit by regulating the conduction time of the first switching unit, and adjusts the current in the circuit by adjusting the impedance value of the impedance switching module connected in the circuit; this avoids long-term operation in a high-impedance circuit, greatly reducing power loss.

Description

Technical Field

[0001] This application relates to the field of electronic technology, specifically to a diode spike current suppression circuit. Background Technology

[0002] Air conditioners are widely used in modern society, and the design of air conditioner circuits is also diverse. Currently, the optimization design of air conditioner power supplies is constantly increasing, among which PFC (Power Factor Correction) circuit design is widely used in air conditioning equipment. PFC circuits constitute a large proportion of air conditioner design, and since PFC circuits contain various components, the protection design of these components is particularly important, such as the protection design of diodes.

[0003] In related technologies, the current design scheme for diode peak current suppression circuits generally achieves this by adding a resistor. Although adding a resistor can suppress peak current to some extent, it also leads to increased power loss in the circuit. Summary of the Invention

[0004] To at least partially overcome the problem in related technologies that adding a resistor to suppress diode spike current leads to increased power loss in the circuit, this application provides a diode spike current suppression circuit.

[0005] According to a first aspect of the embodiments of this application, a diode spike current suppression circuit is provided for suppressing spike current flowing through a protected diode; the circuit includes: a first switching unit, a current sampling unit, an impedance switching module, and a switching control module;

[0006] The first switching unit, the current sampling unit, and the impedance switching module are connected in series, and this series line is connected in parallel with the protected diode.

[0007] The output terminal of the current sampling unit is connected to the input terminal of the switch control module;

[0008] The first output terminal of the switch control module is connected to the control terminal of the first switch unit and is used to adjust the current flowing through the first switch unit.

[0009] The second and third output terminals of the switch control module are respectively connected to the impedance switching module and are used to adjust the impedance of the impedance switching module.

[0010] Furthermore, the switching control module includes: a main control unit and a pulse width modulation unit;

[0011] The input terminal of the main control unit is connected to the output terminal of the current sampling unit for detecting the current in the circuit; the first output terminal of the main control unit is connected to the input terminal of the pulse width modulation unit, and the output terminal of the pulse width modulation unit is connected to the control terminal of the first switching unit.

[0012] The main control unit is used to output a control signal to the pulse width modulation unit, and the pulse width modulation unit is used to generate a PWM wave with a specified duty cycle according to the control signal.

[0013] Furthermore, the main control unit is used to: when the current in the circuit is greater than the first threshold and less than the second threshold, output a control signal to cause the pulse width modulation unit to reduce the duty cycle of the generated PWM wave.

[0014] Furthermore, the main control unit includes: an MCU chip and a switching transistor Q4;

[0015] The second output terminal of the MCU chip is connected to the control terminal of the second switching unit;

[0016] The second output terminal of the MCU chip is connected to the gate of the switching transistor Q4; the source of the switching transistor Q4 is connected to the control terminal of the third switching unit.

[0017] Furthermore, the impedance switching module includes: a second switching unit, a third switching unit, and an impedance unit;

[0018] The second switching unit and the impedance unit are connected in series, and this series line is connected in parallel with the third switching unit;

[0019] The control terminal of the second switching unit is connected to the second output terminal of the main control unit, and the control terminal of the third switching unit is connected to the third output terminal of the main control unit.

[0020] Furthermore, the impedance unit includes a resistor R1, an inductor L1, and a diode D1;

[0021] The resistor R1 is connected in series with the inductor L1, and the diode D1 is connected in parallel with the inductor L1.

[0022] Furthermore, the second switching unit is a switching transistor Q2, and the third switching unit is a switching transistor Q3.

[0023] Furthermore, the main control unit is used for:

[0024] When the current in the circuit is less than the first current threshold, the second switch unit is turned off and the third switch unit is turned on.

[0025] When the current in the circuit is greater than the second current threshold, the second switch unit is turned on and the third switch unit is turned off.

[0026] Furthermore, the current sampling unit includes a sampling resistor R2 and an operational amplifier U1. The two input terminals of the operational amplifier U1 are respectively connected to the two ends of the sampling resistor R2, and the output terminal of the operational amplifier U1 is connected to the input terminal of the switch control module.

[0027] According to a second aspect of the embodiments of this application, a power factor correction circuit is provided, including a diode spike current suppression circuit as described in any of the above embodiments.

[0028] The technical solutions provided by the embodiments of this application have the following beneficial effects:

[0029] The solution proposed in this application adjusts the current flowing through the first switching unit by regulating the conduction time of the first switching unit, and adjusts the current in the circuit by adjusting the impedance value of the impedance switching module connected to the circuit. When the current is large, it adjusts to high impedance to suppress peak current, and switches to low impedance when the current is low, thereby achieving intelligent regulation. It can also avoid long-term operation in a high impedance circuit, greatly reducing power loss. This solution not only effectively suppresses peak current caused by voltage drop, but also greatly optimizes the regulation capability, making the circuit more stable.

[0030] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] Figure 1 This is a block diagram of a diode spike suppression circuit shown in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of a diode spike suppression circuit shown in an embodiment of the present invention.

[0034] Figure 3 This is a flowchart illustrating the operation of a diode spike suppression circuit according to an embodiment of the present invention.

[0035] In the diagram: 110 - Impedance switching module; 120 - Switch control module; 101 - First switch unit; 102 - Second switch unit; 103 - Third switch unit; 104 - Current sampling unit; 105 - Impedance unit; 106 - Main control unit; 107 - Pulse width modulation unit. Detailed Implementation

[0036] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0037] Air conditioners are used in a wide variety of scenarios, and voltage drops can occur due to various factors. To address this issue, this application provides a diode spike current suppression circuit for PFC circuits, which suppresses spike current flowing through the protected diode, effectively solving the problem of circuit malfunction caused by spike current.

[0038] Figure 1 This is a block diagram illustrating a diode spike current suppression circuit according to an exemplary embodiment. The current may include: a first switching unit 101, a current sampling unit 104, an impedance switching module 110, and a switching control module 120.

[0039] The first switching unit 101, the current sampling unit 104, and the impedance switching module 110 are connected in series, and this series line is connected in parallel with the protected diode. The output terminal of the current sampling unit 104 is connected to the input terminal of the switching control module 120.

[0040] The first output terminal of the switch control module 120 is connected to the control terminal of the first switch unit 101 and is used to adjust the current flowing through the first switch unit 101. The second and third output terminals of the switch control module 120 are respectively connected to the impedance switching module 110 and are used to adjust the impedance of the impedance switching module 110.

[0041] The solution proposed in this application adjusts the current flowing through the first switching unit 101 by regulating the conduction time of the first switching unit 101, and adjusts the current in the circuit by adjusting the impedance value of the impedance switching module 110 connected to the circuit. When the current is large, it adjusts to high impedance to suppress peak current, and switches to low impedance when the current is low, thereby achieving intelligent regulation. It can also avoid long-term operation in a high impedance circuit, greatly reducing power loss. This solution not only effectively suppresses peak current caused by voltage drop, but also greatly optimizes the regulation capability, making the circuit more stable.

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0043] like Figure 2As shown, in one embodiment of this application, the circuit includes the following components: R1 is a current-limiting resistor; R2 is a sampling resistor; resistors R3 to R6 work together to determine the operational amplifier gain; L1 is an inductor used to suppress peak current; L2 is a PFC inductor; Q1, Q2, and Q3 are IGBTs (Insulated Gate Bipolar Transistors); Q4 is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor); C1 is a capacitor for filtering and energy storage; D1 is a chip diode used to protect inductor L1; and D2 is a PFC diode.

[0044] In practical applications, the current sampling unit 104 includes a sampling resistor R2 and an operational amplifier U1. The two input terminals of the operational amplifier U1 are respectively connected to the two ends of the sampling resistor R2, and the output terminal of the operational amplifier U1 is connected to the input terminal of the switch control module 120.

[0045] like Figure 2 As shown, the switch control module 120 includes a main control unit 106 and a pulse width modulation unit 107. The input terminal of the main control unit 106 is connected to the output terminal of the current sampling unit 104, and is used to detect the current in the circuit. The first output terminal of the main control unit 106 is connected to the input terminal of the pulse width modulation unit 107, and the output terminal of the pulse width modulation unit 107 is connected to the control terminal of the first switch unit 101.

[0046] The main control unit 106 is used to output a control signal to the pulse width modulation unit 107, and the pulse width modulation unit 107 is used to generate a PWM wave with a specified duty cycle according to the control signal. (Refer to...) Figure 2 The pulse width modulation unit 107 uses a driver chip, specifically the TS44273.

[0047] The solution proposed in this application, through dual regulation of PWM (Pulse Width Modulation) and high-impedance circuit, not only effectively suppresses the peak current caused by voltage drop, but also greatly optimizes the regulation capability, making the circuit more stable.

[0048] A switch control module 120 is also added, which can switch between high and low impedance circuits. When the current sampling module detects a large current, it switches to the high impedance module to suppress the peak current; when the current is low, it switches back to the original circuit, achieving intelligent regulation. The switch control module 120 also avoids long-term operation in the high impedance circuit, greatly reducing power loss.

[0049] In some embodiments, the main control unit 106 is configured to: when the current in the circuit is greater than a first threshold and less than a second threshold, output a control signal to cause the pulse width modulation unit 107 to reduce the duty cycle of the generated PWM wave.

[0050] Reference Figure 3 The diode spike current suppression circuit of this invention operates as follows: In this invention, the current in the circuit flows through sampling resistor R2, and the current sampling module collects the current at resistor R2. The operational amplifier sends the sampled signal to the main chip. When the sampled current is higher than a preset current value 1 (first threshold) and lower than a preset current value 2 (second threshold), the MCU chip identifies this and adjusts the duty cycle α of the PWM wave output at pin A to 80% of this value. After 100ms, sampling is performed again. If the sampled current is less than the preset current value 1, the output is stable; if the sampled current is still greater than the preset current value 1, the PWM wave duty cycle α is controlled to 60% of this value, and sampling and judgment are performed again after another 100ms. This process is repeated until the output is stable. The duty cycle is adjusted via the driver chip output, controlling IGBT Q1 to increase its voltage and decrease the current flowing through it, achieving the effect of suppressing current. At this time, pin B outputs a low level, causing MOSFET Q4 and IGBT Q2 to turn off, and Q3 to turn on, connecting to a low-impedance circuit.

[0051] In some embodiments, the main control unit 106 includes an MCU chip and a switching transistor Q4. The second output terminal of the MCU chip is connected to the control terminal of the second switching unit 102. The second output terminal of the MCU chip is connected to the gate of the switching transistor Q4; the source of the switching transistor Q4 is connected to the control terminal of the third switching unit 103.

[0052] In practical applications, the impedance switching module 110 includes a second switching unit 102, a third switching unit 103, and an impedance unit 105. The second switching unit 102 and the impedance unit 105 are connected in series, and this series line is connected in parallel with the third switching unit 103. The control terminal of the second switching unit 102 is connected to the second output terminal of the main control unit 106, and the control terminal of the third switching unit 103 is connected to the third output terminal of the main control unit 106.

[0053] The impedance unit 105 includes a resistor R1, an inductor L1, and a diode D1. The resistor R1 is connected in series with the inductor L1, and the diode D1 is connected in parallel with the inductor L1. The second switching unit 102 is a switching transistor Q2, and the third switching unit 103 is a switching transistor Q3.

[0054] In some embodiments, the main control unit 106 is used to: control the second switch unit 102 to turn off and the third switch unit 103 to turn on when the current in the circuit is less than the first current threshold; and control the second switch unit 102 to turn on and the third switch unit 103 to turn off when the current in the circuit is greater than the second current threshold.

[0055] Reference Figure 3 The diode spike current suppression circuit of the present invention operates as follows: When the sampled current is higher than the preset current value 1 and simultaneously higher than the preset current value 2, the main chip identifies this and outputs a high-level signal at pin B, controlling MOSFET Q4 and IGBT Q2 to conduct. The conduction of Q4 grounds the base of IGBT Q3, thus turning it off. The circuit is connected to a high-impedance loop composed of resistors and inductors. At this time, the current flowing through the diode is suppressed, thus protecting the diode. When the sampled current is less than the preset current value 1, a PWM wave with a duty cycle of α is output at pin A, and a low-level signal is output at pin B, controlling MOSFET Q4 and IGBT Q2 to turn off and Q3 to conduct, connecting to the low-impedance loop. The circuit then operates normally.

[0056] This invention primarily employs a dual control method—PWM duty cycle regulation and high / low impedance loop switching—to suppress current spikes caused by voltage dips. This dual regulation method allows for timely transition to secondary control when a current surge causes primary PWM regulation to fail, switching to a high-impedance loop and preventing situations where the primary regulation threshold is exceeded and cannot be suppressed. Once the surge current is significantly suppressed, the control method switches back to primary PWM regulation, switching to a low-impedance loop, ensuring normal circuit operation and avoiding power consumption caused by prolonged high-impedance loop operation. Furthermore, the addition of a current spike suppression module allows switching based on current value without affecting normally operating loops. This design offers advantages such as simple circuit structure, ease of implementation, reliable performance, and small size.

[0057] Embodiments of this application also provide a power factor correction circuit, including a diode spike current suppression circuit as described in any of the above embodiments.

[0058] Regarding the power factor correction circuit in the above embodiments, the specific steps of each module's operation have been described in detail in the embodiments related to the method, and will not be elaborated further here. It is understood that the same or similar parts in the above embodiments can be referred to each other, and content not described in detail in some embodiments can be found in the same or similar content in other embodiments.

[0059] It should be noted that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means at least two.

[0060] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is 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. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A diode spike current suppression circuit, used to suppress spike current flowing through the protected diode; characterized in that, The circuit includes: a first switching unit, a current sampling unit, an impedance switching module, and a switching control module; The first switching unit, the current sampling unit, the impedance switching module, and the capacitor are connected in series and then in parallel across the protected diode. The output terminal of the current sampling unit is connected to the input terminal of the switch control module; The first output terminal of the switch control module is connected to the control terminal of the first switch unit and is used to adjust the current flowing through the first switch unit. The second and third output terminals of the switch control module are respectively connected to the impedance switching module and are used to adjust the impedance of the impedance switching module.

2. The diode spike current suppression circuit according to claim 1, characterized in that, The switching control module includes: a main control unit and a pulse width modulation unit; The input terminal of the main control unit is connected to the output terminal of the current sampling unit for detecting the current in the circuit; the first output terminal of the main control unit is connected to the input terminal of the pulse width modulation unit, and the output terminal of the pulse width modulation unit is connected to the control terminal of the first switching unit. The main control unit is used to output a control signal to the pulse width modulation unit, and the pulse width modulation unit is used to generate a PWM wave with a specified duty cycle according to the control signal.

3. The diode spike current suppression circuit according to claim 2, characterized in that, The main control unit is used to: when the current in the circuit is greater than a first threshold and less than a second threshold, output a control signal to reduce the duty cycle of the generated PWM wave by the pulse width modulation unit.

4. The diode spike current suppression circuit according to claim 2, characterized in that, The impedance switching module includes: a second switching unit, a third switching unit, and an impedance unit; The second switching unit and the impedance unit are connected in series, and this series line is connected in parallel with the third switching unit; The control terminal of the second switching unit is connected to the second output terminal of the main control unit, and the control terminal of the third switching unit is connected to the third output terminal of the main control unit.

5. The diode spike current suppression circuit according to claim 4, characterized in that, The main control unit includes: an MCU chip and a switching transistor Q4; The second output terminal of the MCU chip is connected to the control terminal of the second switching unit; The second output terminal of the MCU chip is connected to the gate of the switching transistor Q4; the source of the switching transistor Q4 is connected to the control terminal of the third switching unit.

6. The diode spike current suppression circuit according to claim 5, characterized in that, The impedance unit includes a resistor R1, an inductor L1, and a diode D1; The resistor R1 is connected in series with the inductor L1, and the diode D1 is connected in parallel with the inductor L1.

7. The diode spike current suppression circuit according to claim 5, characterized in that, The second switching unit is a switching transistor Q2, and the third switching unit is a switching transistor Q3.

8. The diode spike current suppression circuit according to claim 5, characterized in that, The main control unit is used for: When the current in the circuit is less than the first current threshold, the second switch unit is turned off and the third switch unit is turned on. When the current in the circuit is greater than the second current threshold, the second switch unit is turned on and the third switch unit is turned off.

9. The diode spike current suppression circuit according to any one of claims 1-4, characterized in that, The current sampling unit includes a sampling resistor R2 and an operational amplifier U1. The two input terminals of the operational amplifier U1 are respectively connected to the two ends of the sampling resistor R2, and the output terminal of the operational amplifier U1 is connected to the input terminal of the switch control module.

10. A power factor correction circuit, characterized in that, Includes the diode spike current suppression circuit as described in any one of claims 1-9.

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