Switch driving circuit and related device

Abstract

The invention discloses a switch driving circuit and a related device, the switch driving circuit comprises a comparison circuit and a driving circuit, when the drain-source voltage of a first switch device represents a zero-point voltage turn-on condition, the comparison circuit outputs a first voltage to the driving circuit, and when the second driving signal of a second switch device is a first level, the comparison circuit outputs a second voltage to the driving circuit. The driving circuit controls the first switching device to be turned on. Therefore, the voltage change condition of the first switching device is reflected through the drain-source voltage of the first switching device, and the first voltage is output when the drain-source voltage meets the zero-point voltage switching-on condition, so that the driving circuit controls the first switching device to be switched on when the first voltage is greater than the second reference voltage; the first switching device can be immediately switched on without waiting for the end of a dead zone, so that the loss is reduced and the efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a switching driving circuit and related device. BACKGROUND

[0002] The bridge arm structure is a common structure in a circuit, and mainly composed of two series-connected switching devices. In order to avoid the two switching devices being directly connected in series in the up-down switching process, a dead time is needed to be added. Further, in order to reduce the loss of the switching device in the up-down switching process, a zero-voltage turn-on technology is generally used, that is, in the dead time, the voltage of the switching device to be turned on is reduced to zero before being turned on, so as to reduce the loss.

[0003] However, since the time of the dead time is fixed, after the voltage of the switching device to be turned on is reduced to zero, the switching device will be turned on only after the end of the dead time, which will bring additional loss. SUMMARY

[0004] Based on the above problems, the present application provides a switching driving circuit and related device, which aims to reduce the loss of the circuit.

[0005] The embodiments of the present application disclose the following technical solutions:

[0006] In a first aspect, the embodiments of the present application provide a switching driving circuit, comprising: a comparison circuit and a driving circuit;

[0007] The first input end of the comparison circuit is connected with a first reference voltage, the second input end of the comparison circuit is connected with the drain-source voltage of a first switching device, the output end of the comparison circuit is connected with the first input end of the driving circuit, the output end of the driving circuit is connected with the control end of the first switching device, and the second input end of the driving circuit is connected with a second reference voltage and a second driving signal corresponding to a second switching device; and the first switching device and the second switching device are connected in series.

[0008] The comparison circuit is configured to output a first voltage when the drain-source voltage represents a zero-voltage turn-on condition.

[0009] The driving circuit is configured to control the first switching device to be turned on when the second driving signal is a first level and the first voltage is greater than the second reference voltage.

[0010] Optionally, a dead-time limiting circuit is further included, the first input end of the dead-time limiting circuit is connected with the output end of the driving circuit and the first driving signal of the first switching device, the second input end of the dead-time limiting circuit is connected with a third reference voltage, and the output end of the dead-time limiting circuit is connected with the control end of the first switching device.

[0011] the dead-time limiting circuit is configured to control the first switch device to be turned on when the first drive signal is at a first level and a voltage at the first input terminal of the dead-time limiting circuit is greater than the third reference voltage; or

[0012] the dead-time limiting circuit is configured to control the first switch device to be turned on when the first drive signal is at a second level.

[0013] Optionally, the comparison circuit comprises a first hysteresis comparator, a first input terminal of the first hysteresis comparator is connected to the first reference voltage, a second input terminal of the first hysteresis comparator is connected to the drain-source voltage, and an output terminal of the first hysteresis comparator is connected to a first input terminal of the drive circuit.

[0014] Optionally, the comparison circuit further comprises a first resistor, a second resistor, a third resistor and a fourth resistor, a first terminal of the first resistor is connected to the drain-source voltage, a second terminal of the first resistor is connected to a first terminal of the second resistor, the second terminal of the first resistor is connected to the second input terminal of the first hysteresis comparator, a second terminal of the second resistor is grounded, a first terminal of the third resistor is connected to the first power supply, a second terminal of the third resistor is connected to a first terminal of the fourth resistor, the second terminal of the third resistor is connected to the first input terminal of the first hysteresis comparator, and a second terminal of the fourth resistor is grounded.

[0015] Optionally, the first hysteresis comparator comprises a fifth resistor and a first comparator, a first terminal of the fifth resistor is connected to a first input terminal of the first comparator, and a second terminal of the fifth resistor is connected to an output terminal of the first comparator; wherein the first input terminal of the first comparator serves as a first input terminal of the first hysteresis comparator, a second input terminal of the first comparator serves as a second input terminal of the first hysteresis comparator, and the output terminal of the first comparator serves as an output terminal of the first hysteresis comparator.

[0016] Optionally, the drive circuit comprises a second hysteresis comparator, a first input terminal of the second hysteresis comparator is connected to an output terminal of the comparison circuit, a second input terminal of the second hysteresis comparator is connected to the second reference voltage and the second drive signal, and an output terminal of the second hysteresis comparator is connected to a control terminal of the first switch device.

[0017] Optionally, the drive circuit further comprises a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor; a first end of the sixth resistor is connected to an output end of the comparison circuit, a second end of the sixth resistor is connected to a first end of the seventh resistor, the second end of the sixth resistor is connected to a first input end of the second hysteresis comparator, a second end of the seventh resistor is grounded, a first end of the eighth resistor is connected to the second drive signal, a second end of the eighth resistor is connected to a common end of the ninth resistor and the tenth resistor, a first end of the ninth resistor is connected to a second power supply, a second end of the tenth resistor is grounded, and the common end of the ninth resistor and the tenth resistor is connected to a second input end of the second hysteresis comparator.

[0018] Optionally, the second hysteresis comparator comprises an eleventh resistor and a second comparator, a first end of the eleventh resistor is connected to a first input end of the second comparator, and a second end of the eleventh resistor is connected to an output end of the second comparator; wherein a second input end of the second comparator is used as a second input end of the second hysteresis comparator, a second input end of the second comparator is used as a second input end of the second hysteresis comparator, and an output end of the second comparator is used as an output end of the second hysteresis comparator.

[0019] Optionally, the dead-zone limiting circuit comprises a third comparator, a first input end of the third comparator is connected to an output end of the drive circuit and a first drive signal of the first switching device, a second input end of the third comparator is connected to the third reference voltage, and an output end of the third comparator is connected to a control end of the first switching device.

[0020] Optionally, the dead-zone limiting circuit further comprises a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor and a seventeenth resistor, a first end of the twelfth resistor is connected to an output end of the drive circuit, a second end of the twelfth resistor is connected to a first end of the thirteenth resistor and a second end of the fifteenth resistor, a second end of the thirteenth resistor is grounded, a first end of the fourteenth resistor is connected to the third power supply and a first end of the sixteenth resistor, a second end of the fourteenth resistor is connected to a first end of the fifteenth resistor, a common end of the fourteenth resistor and the fifteenth resistor is connected to the first drive signal, a second end of the fifteenth resistor is connected to a first input end of the third comparator, a second end of the sixteenth resistor is connected to a first end of the seventeenth resistor and a second input end of the third comparator, and a second end of the seventeenth resistor is grounded.

[0021] Optionally, the comparison circuit is configured to output a first voltage when the drain-source voltage meets a preset voltage range.

[0022] In a second aspect, the embodiments of the present application provide a power converter, the power converter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0023] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0024] In a third aspect, the embodiments of the present application provide a direct current-direct current (DC-DC) converter, the DC-DC converter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0025] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on

[0026] In a fourth aspect, the embodiments of the present application provide an inverter, the inverter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0027] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0028] In a fifth aspect, the embodiments of the present application provide a rectifier, the rectifier comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0029] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0030] In a sixth aspect, the embodiments of the present application provide an alternating current-alternating current (AC-AC) converter, the AC-AC converter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0031] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0032] In a seventh aspect, the embodiments of the present application provide an alternating current-direct current (AC-DC) converter, the AC-DC converter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0033] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0034] In an eighth aspect, the embodiments of the present application provide a direct current-alternating current (DC-AC) converter, the DC-AC converter comprising a bridge arm circuit and the switch driving circuit according to the first aspect;

[0035] The switch driving circuit is configured to drive the switch device in the bridge arm circuit to be turned on.

[0036] The switch driving circuit provided by the application, by setting a comparison circuit and a driving circuit, when the drain-source voltage of the first switch device represents the zero voltage turn-on condition, the comparison circuit outputs a first voltage to the driving circuit, and when the second driving signal of the second switch device is the first level, the driving circuit controls the first switch device to be turned on. In this way, the voltage change of the first switch device is reflected by the drain-source voltage of the first switch device, and when the drain-source voltage meets the zero voltage turn-on condition, the first voltage is output, so that the driving circuit controls the first switch device to be turned on when the first voltage is greater than the second reference voltage, without waiting for the dead zone to end, the first switch device can be immediately turned on, thereby reducing the loss and improving the efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0038] Figure 1 A structural schematic diagram of a bridge arm circuit provided by an embodiment of the present application;

[0039] Figure 2 A structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0040] Figure 3 A first structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0041] Figure 4 A second structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0042] Figure 5 A third structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0043] Figure 6 A fourth structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0044] Figure 7 A fifth structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0045] Figure 8 A sixth structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0046] Figure 9 A seventh structural schematic diagram of a switch driving circuit provided by an embodiment of the present application;

[0047] Figure 10 FIG. 8 is a schematic diagram of an eighth structure of a switch driving circuit according to an embodiment of the present application;

[0048] Figure 11 FIG. 9 is a schematic diagram of a ninth structure of a switch driving circuit according to an embodiment of the present application;

[0049] Figure 12 FIG. 10 is a schematic diagram of a tenth structure of a switch driving circuit according to an embodiment of the present application;

[0050] Figure 13 FIG. 11 is a schematic diagram of voltages of parts of a switch driving circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0051] Referring to Figure 1 FIG. 1 is a schematic diagram of a structure of a bridge arm circuit according to an embodiment of the present application.

[0052] In combination Figure 1 As shown in the figure, the bridge arm circuit includes two series-connected switch devices, which are a first switch device K1 and a second switch device K2. In order to avoid the first switch device K1 and the second switch device K2 being directly connected in the up-down switching process of the first switch device K1 and the second switch device K2, a dead time needs to be added.

[0053] The dead time means that the same phase of the upper and lower bridge arms is intentionally added to the closing time of the bridge arms, which is used to prevent the upper and lower tubes from being directly connected, resulting in serious consequences such as board explosion. Specifically, the dead time is a time period in which the upper half bridge (or high-side power transistor) of one bridge arm is turned off, and then the lower half bridge (or low-side power transistor) is turned on after a delay, or the lower half bridge is turned off, and then the upper half bridge is turned on after a delay.

[0054] Further, in order to reduce the loss of the switch device in the up-down switching process, a zero-voltage turn-on technology is generally used, that is, in the dead time, the voltage of the switch device to be turned on is reduced to zero before being turned on, which can reduce the loss. Figure 1 As shown in FIG. 1, the point Q between the first switch device K1 and the second switch device K2.

[0055] As an example, it is assumed that the first switch device K1 is turned off and the second switch device K2 is closed, and at this time, the first switch device K1 needs to be turned on. Then, the second switch device K2 needs to be turned off, and the dead time needs to be waited. In the dead time, the voltage of the first switch device K1 is reduced to zero, and after the dead time ends, the first switch device K1 is closed.

[0056] However, since the dead time is fixed, even after the voltage of the switching device about to be turned on drops to 0, the dead time must still be waited for before the switching device can be turned on, which will bring additional losses. Based on the previous example, assuming the dead time is 10 seconds, and the voltage of the first switching device K1 drops to 0 in the 3rd second, since the dead time has not yet ended, it will take 10 seconds before the first switching device K1 can be turned on. During the 7 seconds of waiting for the dead time to end, the current in the circuit needs to flow through other paths (such as freewheeling diodes), which will generate some conduction losses.

[0057] To address the aforementioned technical problems, this application provides a switch driving circuit and related apparatus. The switch driving circuit includes a comparator circuit and a driving circuit. When the drain-source voltage of a first switching device represents a zero-point voltage turn-on condition, the comparator circuit outputs a first voltage to the driving circuit. Furthermore, when the second driving signal of a second switching device is at a first level, the driving circuit controls the first switching device to turn on. Thus, the drain-source voltage of the first switching device reflects its voltage change. When the drain-source voltage meets the zero-point voltage turn-on condition, the first voltage is output, causing the driving circuit to control the first switching device to turn on when the first voltage is greater than a second reference voltage. This allows the first switching device to be turned on immediately without waiting for the dead time to end, thereby reducing losses and improving efficiency.

[0058] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0059] See Figure 2 This figure is a schematic diagram of a switch driving circuit provided in an embodiment of this application, combined with... Figure 2 As shown, the switch driving circuit provided in this application embodiment may include: a comparator circuit 201 and a driving circuit 202.

[0060] The first input terminal of the comparator circuit 201 is connected to the first reference voltage U1, the second input terminal of the comparator circuit 201 is connected to the drain-source voltage Vds of the first switching device K1, the output terminal of the comparator circuit 201 is connected to the first input terminal of the drive circuit 202, the output terminal of the drive circuit 202 is connected to the control terminal of the first switching device K1, and the second input terminal of the drive circuit 202 is connected to the second reference voltage U2 and the second drive signal PWM2 corresponding to the second switching device K2; the first switching device K1 and the second switching device K2 are connected in series.

[0061] Switching devices refer to devices used to achieve the functions of turning on and off, such as insulated gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), thyristors, etc., without being specifically limited here.

[0062] It should be noted that, in order to illustrate the control process for the switches in the bridge arm structure, the embodiments of this application use the above-mentioned... Figure 1 The bridge arm structure is used as an example for illustration; other bridge arm structures are implemented in the same principle as in this application. Furthermore, in this embodiment, to facilitate the explanation of the switching process between the two switching devices, any one of the two switching devices is used as the first switching device, and the other switching device is used as the second switching device. Figure 1 The example illustrates the use of the upper half-bridge switching device as the first switching device and the lower half-bridge switching device as the second switching device. In some implementations, the lower half-bridge switching device may be used as the first switching device and the upper half-bridge switching device as the second switching device; this is not specifically limited here.

[0063] Drain-source voltage (Vds) refers to the voltage difference between the source and drain of a switching device when it is operating, caused by the internal structure of the device. Specifically, drain-source voltage is the maximum voltage that the device can withstand when it is off.

[0064] Reference voltage refers to the voltage used to provide a reference standard for the circuit. In the embodiments of this application, the first reference voltage of the comparison circuit and the second reference voltage of the driving circuit may be the same or different, and no specific limitation is made here.

[0065] It should be noted that, in the embodiments of this application, the example is taken as the second switching device changing from on to off, and the first switching device changing from off to on.

[0066] Comparator circuit 201 is used to output a first voltage when the drain-source voltage represents the zero-voltage turn-on condition.

[0067] Zero-Voltage Switching (ZVS) is a soft-switching technology designed to reduce energy loss and electromagnetic interference during switching, while improving switching frequency and circuit efficiency. ZVS refers to the process where the voltage across the switching transistor drops to zero or near zero before the transistor is turned on, thus enabling the switching device to turn on with almost no voltage drop. ZVS reduces transient current spikes and switching losses during the switching process.

[0068] It should be understood that drain-source voltage refers to the voltage difference between the drain and source of a switching device when it is in the off state. The magnitude of the drain-source voltage directly affects the operating state and performance of the switching device. If the drain-source voltage is high before the switching device is turned on, a large transient current and switching losses will be generated during turn-on; however, if the drain-source voltage can be reduced to zero or close to zero, zero-voltage turn-on can be achieved, thereby reducing switching losses and electromagnetic interference.

[0069] Therefore, in this embodiment, the drain-source voltage of the first switching device reflects the voltage change of the first switching device. When the drain-source voltage of the first switching device meets the zero-voltage turn-on condition, that is, the voltage of the first switching device is zero or approximately zero, the loss generated by turning on the first switching device is minimal, and the comparator circuit can output the first voltage.

[0070] The first voltage refers to the voltage output by the comparator circuit when the drain-source voltage characterization meets the zero-voltage turn-on condition. The first voltage can be a high level or a low level, without specific limitations.

[0071] The driving circuit 202 is used to control the first switching device K1 to turn on when the second driving signal PWM2 is at the first level and the first voltage is greater than the second reference voltage U2.

[0072] A drive signal refers to a signal used to turn a switching device on or off. A second drive signal refers to a signal used to turn a second switching device on or off.

[0073] The first level refers to the level state of the drive signal when the second switching device is turned off. For example, a low level (0) represents the second switching device being turned off, and a high level (1) represents the second switching device being turned on.

[0074] It should be understood that in the bridge arm circuit, the two switching devices are turned on alternately. When the second switching device is in the on state, the first switching device cannot be turned on; similarly, when the first switching device is on, the second switching device is in the off state. Therefore, in the embodiments of this application, the on condition of the first switching device is that the second switching device is off, that is, the second driving signal is at the first level.

[0075] It should be understood that when the comparator circuit outputs a first voltage, indicating that the first switching device has reached the zero-voltage turn-on condition, and the second drive signal is at the first level, indicating that the second switching device is in the off state, then the first voltage is greater than the second reference voltage, and the drive circuit controls the first switching device to turn on.

[0076] In one possible implementation, comparator circuit 201 is configured to output a first voltage when the drain-source voltage Vds meets a preset voltage range. It should be understood that when the drain-source voltage meets the preset voltage range, it represents a zero-point voltage turn-on condition, and the comparator circuit can output the first voltage. The preset voltage range indicates the voltage range within which the zero-point voltage turn-on condition is met.

[0077] In this embodiment, the drain-source voltage of the first switching device reflects the voltage change of the first switching device. When the drain-source voltage meets the zero-point voltage turn-on condition, the first voltage is output. Furthermore, the second driving signal reflects the conduction status of the second switching device. When the second driving signal is at the first level, it indicates that the second switching device is in the off state. Then, when the first voltage is greater than the second reference voltage, the driving circuit controls the first switching device to turn on. There is no need to wait for the dead zone to end and the first switching device is turned on immediately when the voltage of the first switching device meets the zero-point voltage turn-on condition, thereby reducing losses and improving efficiency.

[0078] Further research on the switch drive circuit based on the above embodiments revealed that voltage fluctuations may occur due to certain factors. These fluctuations could cause the drive circuit to fail to control the first switching device to conduct. For example, if the first voltage fluctuates between 8.9V and 9.1V, and the second reference voltage is 9V, when the first voltage remains at 8.9V, it will always be lower than the second reference voltage, preventing the drive circuit from controlling the first switching device to conduct.

[0079] To solve the above problems, combined with Figure 3 As shown, the switch driving circuit may include a comparator circuit 201, a drive circuit 202, and a dead-time limiting circuit 301. The first input terminal of the dead-time limiting circuit 301 is connected to the output terminal of the drive circuit 202 and the first drive signal PWM1 of the first switching device K1. The second input terminal of the dead-time limiting circuit 301 is connected to the third reference voltage. The output terminal of the dead-time limiting circuit 301 is connected to the control terminal of the first switching device K1.

[0080] The first driving signal refers to the signal used to drive the first switching device to turn on or off, and the third reference voltage refers to the voltage used to provide a reference standard for the dead-time limiting circuit. In the embodiments of this application, the first reference voltage of the comparison circuit, the second reference voltage of the driving circuit, and the third reference voltage of the dead-time limiting circuit may be the same or different, and no specific limitation is made here.

[0081] The dead-time limiting circuit 301 is used to control the first switching device K1 to turn on when the first driving signal PWM1 is at the first level and the voltage at the first input terminal of the dead-time limiting circuit 301 is greater than the third reference voltage; or, when the first driving signal PWM1 is at the second level, control the first switching device K1 to turn on.

[0082] It should be understood that when the first driving signal is at the first level and is consistent with the level state of the second driving signal, it indicates that both the first switching device and the second switching device are in the off state. At this time, if the voltage at the first input end of the dead-time limiting circuit is greater than the third reference voltage, it means that the voltage at the output end of the driving circuit is greater than the third reference voltage. At this time, the dead-time limiting circuit can directly control the first switching device to conduct without waiting for the end of the dead time. However, if the voltage at the first input end of the dead-time limiting circuit is always less than the third reference voltage, when the dead time of the first switching device ends, it will directly control the first switching device to conduct, that is, the first driving signal is at the second level, and the first switching device is forced to turn on, avoiding the problem that the first switching device cannot turn on caused by voltage fluctuations, and improving the reliability and stability of the circuit.

[0083] Based on the switching drive circuit provided in the above embodiment, combined with Figure 4 As shown, the comparison circuit 201 includes a first hysteresis comparator 401. The first input end of the first hysteresis comparator 401 is connected to the first reference voltage U1, the second input end of the first hysteresis comparator 401 is connected to the drain-source voltage Vds, and the output end of the first hysteresis comparator 401 is connected to the first input end of the drive circuit 202.

[0084] A hysteresis comparator, also known as a hysteresis comparator, Schmitt trigger, or hysteresis comparator, is an important component widely used in electronic devices and circuits. Its main function is to compare input signals and output a digital signal to indicate whether the input signal is higher or lower than a certain threshold. The characteristic of a hysteresis comparator is that it introduces a hysteresis characteristic, which not only enhances the noise suppression ability of the circuit but also improves the stability of the system.

[0085] It should be understood that due to the characteristics of the first hysteresis comparator, in some implementation manners, the comparison circuit can set two thresholds V1 and V2, where V1 > V2. When Vds < V2, the comparison circuit outputs a high level (i.e., the first voltage), and when Vds > V1, the comparator outputs a low level.

[0086] In the embodiment of the present application, the comparison circuit 201 sets the first hysteresis comparator and utilizes its hysteresis characteristic, that is, two different thresholds (upper threshold and lower threshold) are set. When the drain-source voltage approaches these thresholds, the state change of the output signal does not occur instantaneously but requires the input signal to cross the entire hysteresis region. This hysteresis characteristic effectively reduces false triggering caused by noise or signal fluctuations, improves the anti-interference ability of the circuit, and thus improves the stability of the system.

[0087] Based on the switching drive circuit provided in the above embodiment, combined with Figure 5As shown, the comparator circuit 201 may include a first hysteresis comparator 401, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The first terminal of the first resistor R1 is connected to the drain-source voltage Vds, the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2, the second terminal of the first resistor R1 is connected to the second input terminal of the first hysteresis comparator 401, the second terminal of the second resistor R2 is grounded, the first terminal of the third resistor R3 is connected to the first power supply VCC1, the second terminal of the third resistor R3 is connected to the first terminal of the fourth resistor R4, the second terminal of the third resistor R3 is connected to the first input terminal of the first hysteresis comparator 401, and the second terminal of the fourth resistor R4 is grounded.

[0088] The first power source refers to the power source used to provide voltage, and the first reference voltage is obtained based on the first power source.

[0089] It should be understood that, in this embodiment, the drain-source voltage Vds is proportionally reduced to a range that the hysteresis comparator 401 can handle through a voltage divider network composed of the first resistor R1 and the second resistor R2. Simultaneously, another voltage divider network composed of the third resistor R3 and the fourth resistor R4 provides a first reference voltage to the first input terminal of the first hysteresis comparator 401, enabling the first hysteresis comparator 401 to accurately compare the drain-source voltage with the set threshold, thereby achieving precise control.

[0090] Based on the switch driving circuit provided in the above embodiments, combined with Figure 6 As shown, the first hysteresis comparator 401 includes a fifth resistor R5 and a first comparator 601. The first end of the fifth resistor R5 is connected to the first input terminal of the first comparator 601, and the second end of the fifth resistor R5 is connected to the output terminal of the first comparator 601. The first input terminal of the first comparator 601 serves as the first input terminal of the first hysteresis comparator 401, the second input terminal of the first comparator 601 serves as the second input terminal of the first hysteresis comparator 401, and the output terminal of the first comparator 601 serves as the output terminal of the first hysteresis comparator 401.

[0091] It should be noted that, Figure 6 A in the above shows Figure 4 Based on this, a schematic diagram of the first hysteresis comparator 401 including the fifth resistor R5 and the first comparator 601 is provided. Figure 6 B in the above shows Figure 5 Based on this, a schematic diagram of the first hysteresis comparator 401 including the fifth resistor R5 and the first comparator 601 is provided.

[0092] It should be understood that, in this embodiment, the fifth resistor R5 is connected between the first input terminal and the output terminal of the first comparator 601, forming a positive feedback loop. This positive feedback loop causes the output state of the first comparator to flip when the input signal reaches a certain threshold, and due to the presence of positive feedback, the output state needs to reach another lower threshold before flipping again when the input signal recedes. This characteristic is called hysteresis, which makes the first comparator insensitive to small fluctuations in the input signal, enhancing the circuit's anti-interference capability.

[0093] Based on the switch driving circuit provided in the above embodiments, combined with Figure 7 As shown, the driving circuit 202 includes a second hysteresis comparator 701. The first input terminal of the hysteresis comparator is connected to the output terminal of the comparator circuit 201. The second input terminal of the second hysteresis comparator 701 is connected to the second reference voltage U2 and the second driving signal PWM2. The output terminal of the second hysteresis comparator 701 is connected to the control terminal of the first switching device K1.

[0094] In this embodiment, the driving circuit 202 utilizes a second hysteresis comparator, which sets two different thresholds (upper threshold and lower threshold). When the first voltage approaches these thresholds, the state change of the output signal does not occur instantaneously, but requires the input signal to traverse the entire hysteresis region. This hysteresis characteristic effectively reduces false triggering caused by noise or signal fluctuations, improves the circuit's anti-interference capability, and thus enhances the system's stability.

[0095] Based on the switch driving circuit provided in the above embodiments, combined with Figure 8 As shown, the driving circuit 202 may include a second hysteresis comparator 701, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10. The first end of the sixth resistor R6 is connected to the output of the comparator circuit 201, the second end of the sixth resistor R6 is connected to the first end of the seventh resistor R7, the second end of the sixth resistor R6 is connected to the first input of the second hysteresis comparator 701, the second end of the seventh resistor R7 is grounded, the first end of the eighth resistor R8 is connected to the second driving signal PWM2, the second end of the eighth resistor R8 is connected to the common terminal of the ninth resistor R9 and the tenth resistor R10, the first end of the ninth resistor R9 is connected to the second power supply VCC2, the second end of the tenth resistor R10 is grounded, and the common terminal of the ninth resistor R9 and the tenth resistor R10 is connected to the second input of the second hysteresis comparator 701.

[0096] The second power source refers to the power source used to provide voltage, and the second reference voltage is obtained based on the second power source.

[0097] It should be understood that, in this embodiment, the first voltage is proportionally reduced to the range that the hysteresis comparator 401 can handle through the voltage divider network composed of the first resistor R6 and the second resistor R7. Simultaneously, another voltage divider network composed of the third resistor R9 and the fourth resistor R10, together with the voltage corresponding to the second drive signal, provides a second reference voltage to the first input terminal of the second hysteresis comparator 701, enabling the second hysteresis comparator 701 to accurately compare the drain-source voltage with the set threshold, thereby achieving precise control.

[0098] Based on the switch driving circuit provided in the above embodiments, combined with Figure 9 As shown, the second hysteresis comparator 701 includes an eleventh resistor R11 and a second comparator 901. The first end of the eleventh resistor R11 is connected to the first input terminal of the second comparator 802, and the second end of the eleventh resistor R11 is connected to the output terminal of the second comparator 802. The second input terminal of the second comparator 901 serves as the second input terminal of the second hysteresis comparator 701, and the output terminal of the second comparator 901 serves as the output terminal of the second hysteresis comparator 701.

[0099] It should be noted that, Figure 9 A in the above shows Figure 7 Based on this, a schematic diagram of the second hysteresis comparator 701 including the eleventh resistor R11 and the second comparator 901 is provided. Figure 9 B in the above shows Figure 8 Based on this, the second hysteresis comparator 701 includes an eleventh resistor R11 and a second comparator 901.

[0100] It should be understood that, in this embodiment, the eleventh resistor R11 is connected between the first input terminal and the output terminal of the second comparator 901, forming a positive feedback loop. This positive feedback loop causes the output state of the second comparator to flip when the input signal reaches a certain threshold, and due to the presence of positive feedback, the output state needs to reach another lower threshold before flipping again when the input signal recedes. This characteristic is called hysteresis, which makes the second comparator insensitive to small fluctuations in the input signal, enhancing the circuit's anti-interference capability.

[0101] Based on the switch driving circuit provided in the above embodiments, combined with Figure 10 As shown, the dead-time limiting circuit 301 includes a third comparator 1001. The first input terminal of the third comparator 1001 is connected to the output terminal of the drive circuit 202 and the first drive signal PWM1 of the first switching device K1. The second input terminal of the third comparator 1001 is connected to the third reference voltage. The output terminal of the third comparator 1001 is connected to the control terminal of the first switching device K1.

[0102] In this embodiment, if the voltage at the first input terminal of the dead-time limiting circuit is always less than the third reference voltage, when the dead time of the first switching device ends, the first switching device will be directly controlled to turn on. That is, the first driving signal is at the second level, which controls the first switching device to be forcibly turned on, avoiding the problem that the first switching device cannot be turned on due to voltage fluctuations, and improving the reliability and stability of the circuit.

[0103] Based on the switch driving circuit provided in the above embodiments, combined with Figure 11 As shown, the dead-time limiting circuit 301 includes a third comparator 1001, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17. The first end of the twelfth resistor R12 is connected to the output terminal of the drive circuit 202. The second end of the twelfth resistor R12 is connected to the first end of the thirteenth resistor R13 and the second end of the fifteenth resistor R15. The second end of the thirteenth resistor R13 is grounded. The first end of the fourteenth resistor R14 is connected to the third power supply and the first end of the sixteenth resistor R16. The second end of the fourteenth resistor R14 is connected to the first end of the fifteenth resistor R15. The common terminal of the fourteenth resistor R14 and the fifteenth resistor R15 is connected to the first drive signal PWM1. The second end of the fifteenth resistor R15 is connected to the first input terminal of the third comparator 1001. The second end of the sixteenth resistor R16 is connected to the first end of the seventeenth resistor R17 and the second input terminal of the third comparator 1001. The second end of the seventeenth resistor R17 is grounded.

[0104] The third power source refers to the power source used to provide voltage, and the third reference voltage is obtained based on the third power source. The first, second, and third power sources can be provided by the same power supply or by different power supplies; no specific limitations are made here.

[0105] The voltage divider network formed by the twelfth resistor R12 and the thirteenth resistor R13 can divide the voltage output by the drive circuit 202 to obtain a voltage range suitable for the input of the third comparator 1001. This voltage divider ensures that the third comparator can accurately receive and compare the signal output by the drive circuit, thereby improving the stability and reliability of the circuit.

[0106] Furthermore, a voltage divider circuit consisting of the sixteenth resistor R16 and the seventeenth resistor R17 is used to provide a precise third reference voltage to the second input terminal of the third comparator 1001. By adjusting the resistance values ​​of these two resistors, the reference voltage can be flexibly set to adapt to different circuit requirements and operating conditions.

[0107] Based on the switch driving circuit provided in the above embodiments, see [link to relevant documentation]. Figure 12This application embodiment also provides a switch driving circuit, which may include: a comparator circuit 201, a drive circuit 202, and a dead-time limiting circuit 301; the comparator circuit 201 may include a first hysteresis comparator 401, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; the first hysteresis comparator 401 includes a fifth resistor R5 and a first comparator 601; the drive circuit 202 may include a second hysteresis comparator 701, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10; the second hysteresis comparator 701 includes an eleventh resistor R11 and a second comparator 901; the dead-time limiting circuit 301 includes a third comparator 1001, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, and a seventeenth resistor R17. The switch driving circuit provided in this application embodiment also includes two PWM isolation chips and one non-isolated drive chip. Two PWM isolation chips are connected to the first drive signal and the second drive signal respectively, and the non-isolated drive chip is located between the output terminal of the dead-time limiting circuit and the control terminal of the first switching device.

[0108] The primary function of a PWM (Pulse Width Modulation) isolation chip is to provide electrical isolation, ensuring electrical separation between the control circuit and the power circuit, thereby improving system safety and reliability. PWM isolation chips achieve electrical isolation between the control circuit and the power circuit through built-in optocouplers or other isolation technologies. This isolation prevents high voltage, high current, and potential noise and interference from being conducted from the power circuit to the control circuit, protecting sensitive components in the control circuit from damage. While providing isolation, the PWM isolation chip can also reliably transmit PWM signals. It can convert the PWM signal in the control circuit into a form suitable for isolated transmission (such as an optical signal), and then convert it into a PWM signal that the power circuit can recognize, achieving accurate signal transmission.

[0109] Non-isolated driver chips are primarily used to turn on the first switching device, enabling precise control over it. Compared to isolated driver chips, non-isolated driver chips lack electrical isolation, but they offer advantages such as simple structure, low cost, and high efficiency. Non-isolated driver chips can convert input voltage or current into a form suitable for driving the first switching device, such as constant current or constant voltage output, thereby achieving precise control over the first switching device. Because they lack additional circuitry such as electrical isolation, non-isolated driver chips can convert electrical energy more efficiently, reduce energy loss, and improve the overall system efficiency. Compared to isolated driver chips, non-isolated driver chips have a simpler structure and lower manufacturing cost.

[0110] It should be noted that for the components in the embodiments of the present application that are the same as those in the above embodiments, the reference numerals of the previous embodiment are used, and for the connection relationships of the same components, refer to the connection relationships described in the above embodiments, and no repeated description will be made here.

[0111] Based on Figure 12 , and further in combination with Figure 13 as shown, Figure 13 the processes of the voltages of the drain-source voltage Vds, the first drive signal PWM1, the second drive signal PWM2, the output of the comparison circuit (the first-stage output), the output of the drive circuit (the second-stage output), and the output of the dead-time limit circuit (the third-stage output) changing with time are respectively shown.

[0112] In the comparison circuit, by setting the resistors R1 - R5, the comparison circuit 201 can set two thresholds V1 and V2, where V1 > V2. When Vds < V2, the first comparator 201 outputs a high level, and when Vds > V1, the first comparator outputs a low level.

[0113] In the drive circuit, by setting the resistors R6 - R11, the following can be achieved:

[0114] When the input of PWM2 is 1, the negative input of the second comparator is large enough so that regardless of the value of the hysteresis output, the output of the second comparator is 0, playing a shielding role.

[0115] When the output of PWM2 is 0, the negative input of the second comparator is a relatively small voltage greater than 0. When the input of the first comparator is 0, the output of the second comparator is 0; when the output of the first comparator is 1, the positive input terminal of the second comparator is greater than the negative input terminal, and at this time the second comparator outputs 1. Even if the input of the first comparator returns to 0, since the output of the second comparator is 1, at this time the positive input of the second comparator is still greater than the negative input, and the output of the second comparator remains 1, that is, it plays a holding role.

[0116] In the dead-time limit circuit, by setting the resistors R12 - R17, the following can be achieved:

[0117] When the input of PWM1 is 0, the negative input terminal of the third comparator is a fixed voltage. When the output of the second comparator is 0, the third comparator outputs 0; when the output of the second comparator is 1, the voltage of the positive input terminal of the third comparator is greater than the negative input terminal voltage, and the third comparator outputs 1, playing a role of directly outputting the drive signal.

[0118] When the input of PWM1 is 1, the voltage of the positive input terminal of the third comparator is pulled to a relatively high voltage. At this time, regardless of whether the output of the second comparator is 0 or 1, the output of the third comparator is 1. That is, it plays a role of forcibly pulling up.

[0119] This application embodiment also provides a power converter, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0120] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0121] This application also provides a DC-DC converter, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0122] The switch drive circuit is used to turn on the switching devices in the bridge arm circuit.

[0123] This application also provides an inverter, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0124] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0125] This application embodiment also provides a rectifier, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0126] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0127] This application embodiment also provides an AC-AC converter, the AC-AC converter including a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0128] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0129] This application also provides an AC-DC converter, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments.

[0130] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0131] This application also provides a DC-AC converter, which includes a bridge arm circuit and a switch drive circuit as described in any of the above embodiments;

[0132] The switch drive circuit is used to drive the switching devices in the bridge arm circuit to conduct.

[0133] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0134] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A switch driving circuit, characterized in that, include: Comparison circuit and drive circuit; The first input terminal of the comparator circuit is connected to a first reference voltage, the second input terminal of the comparator circuit is connected to the drain-source voltage of the first switching device, the output terminal of the comparator circuit is connected to the first input terminal of the drive circuit, the output terminal of the drive circuit is connected to the control terminal of the first switching device, and the second input terminal of the drive circuit is connected to a second reference voltage and a second drive signal corresponding to the second switching device; the first switching device and the second switching device are connected in series. The comparator circuit is used to output a first voltage when the drain-source voltage represents a zero-voltage turn-on condition. The driving circuit is used to control the first switching device to turn on when the second driving signal is at a first level and the first voltage is greater than the second reference voltage.

2. The switch driving circuit according to claim 1, characterized in that, It also includes a dead-time limiting circuit, wherein the first input terminal of the dead-time limiting circuit is connected to the output terminal of the drive circuit and the first drive signal of the first switching device, the second input terminal of the dead-time limiting circuit is connected to the third reference voltage, and the output terminal of the dead-time limiting circuit is connected to the control terminal of the first switching device; The dead-time limiting circuit is used to control the first switching device to turn on when the first driving signal is at a first level and the voltage at the first input terminal of the dead-time limiting circuit is greater than the third reference voltage. or, When the first drive signal is at the second level, the first switching device is turned on.

3. The switch driving circuit according to claim 1, characterized in that, The comparison circuit includes a first hysteresis comparator, the first input terminal of the first hysteresis comparator is connected to the first reference voltage, the second input terminal of the first hysteresis comparator is connected to the drain-source voltage, and the output terminal of the first hysteresis comparator is connected to the first input terminal of the drive circuit.

4. The switch driving circuit according to claim 3, characterized in that, The comparison circuit further includes a first resistor, a second resistor, a third resistor, and a fourth resistor; the first end of the first resistor is connected to the drain-source voltage, the second end of the first resistor is connected to the first end of the second resistor, the second end of the first resistor is connected to the second input terminal of the first hysteresis comparator, the second end of the second resistor is grounded, the first end of the third resistor is connected to the first power supply, the second end of the third resistor is connected to the first end of the fourth resistor, the second end of the third resistor is connected to the first input terminal of the first hysteresis comparator, and the second end of the fourth resistor is grounded.

5. The switch driving circuit according to claim 3 or 4, characterized in that, The first hysteresis comparator includes a fifth resistor and a first comparator. The first end of the fifth resistor is connected to the first input terminal of the first comparator, and the second end of the fifth resistor is connected to the output terminal of the first comparator. The first input terminal of the first comparator serves as the first input terminal of the first hysteresis comparator, the second input terminal of the first comparator serves as the second input terminal of the first hysteresis comparator, and the output terminal of the first comparator serves as the output terminal of the first hysteresis comparator.

6. The switch driving circuit according to claim 1, characterized in that, The driving circuit includes a second hysteresis comparator. The first input terminal of the hysteresis comparator is connected to the output terminal of the comparator circuit. The second input terminal of the second hysteresis comparator is connected to the second reference voltage and the second driving signal. The output terminal of the second hysteresis comparator is connected to the control terminal of the first switching device.

7. The switch driving circuit according to claim 6, characterized in that, The driving circuit further includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor; the first end of the sixth resistor is connected to the output terminal of the comparator circuit, the second end of the sixth resistor is connected to the first end of the seventh resistor, the second end of the sixth resistor is connected to the first input terminal of the second hysteresis comparator, the second end of the seventh resistor is grounded, the first end of the eighth resistor is connected to the second driving signal, the second end of the eighth resistor is connected to the common terminal of the ninth and tenth resistors, the first end of the ninth resistor is connected to the second power supply, the second end of the tenth resistor is grounded, and the common terminal of the ninth and tenth resistors is connected to the second input terminal of the second hysteresis comparator.

8. The switch driving circuit according to claim 6 or 7, characterized in that, The second hysteresis comparator includes an eleventh resistor and a second comparator. The first end of the eleventh resistor is connected to the first input terminal of the second comparator, and the second end of the eleventh resistor is connected to the output terminal of the second comparator. The second input terminal of the second comparator serves as the second input terminal of the second hysteresis comparator, and the output terminal of the second comparator serves as the output terminal of the second hysteresis comparator.

9. The switch driving circuit according to claim 2, characterized in that, The dead-time limiting circuit includes a third comparator. The first input terminal of the third comparator is connected to the output terminal of the driving circuit and the first driving signal of the first switching device. The second input terminal of the third comparator is connected to the third reference voltage. The output terminal of the third comparator is connected to the control terminal of the first switching device.

10. The switch driving circuit according to claim 9, characterized in that, The dead-time limiting circuit further includes a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, and a seventeenth resistor. The first end of the twelfth resistor is connected to the output terminal of the drive circuit. The second end of the twelfth resistor is connected to the first end of the thirteenth resistor and the second end of the fifteenth resistor. The second end of the thirteenth resistor is grounded. The first end of the fourteenth resistor is connected to the third power supply and the first end of the sixteenth resistor. The second end of the fourteenth resistor is connected to the first end of the fifteenth resistor. The common terminal of the fourteenth and fifteenth resistors is connected to the first drive signal. The second end of the fifteenth resistor is connected to the first input terminal of the third comparator. The second end of the sixteenth resistor is connected to the first end of the seventeenth resistor and the second input terminal of the third comparator. The second end of the seventeenth resistor is grounded.

11. The switch driving circuit according to any one of claims 1-10, characterized in that, The comparison circuit is used to output a first voltage when the drain-source voltage meets a preset voltage range.

12. A power converter, characterized in that, The power converter includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

13. A DC-DC converter, characterized in that, The DC-DC converter includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

14. An inverter, characterized in that, The inverter includes a bridge arm circuit and a switching drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

15. A rectifier, characterized in that, The rectifier includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

16. An AC-AC-AC converter, characterized in that, The AC-AC converter includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

17. An AC-DC converter, characterized in that, The AC-DC converter includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

18. A DC-AC converter, characterized in that, The DC-AC converter includes a bridge arm circuit and a switch drive circuit as described in any one of claims 1-11; The switch driving circuit is used to drive the switching devices in the bridge arm circuit to conduct.

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