Bridge circuit and switching power supply

Abstract

The invention provides a bridge circuit and a switching power supply, the bridge circuit comprises at least one bridge arm and at least one anti-crosstalk circuit, the bridge arm comprises two driving switching tubes connected in series, the anti-crosstalk circuit comprises a negation circuit and a clamping switching tube, a first end of the driving switching tube is connected with a controller and a first end of the clamping switching tube, and a second end of the driving switching tube is connected with a second end of the negation circuit. The second end of the driving switch tube is connected with the second end of the clamping switch tube, and the second end of the driving switch tube is connected with the negative electrode of the diode in the driving switch tube. The first end of the driving switch tube and the negation circuit are used for receiving a driving signal sent by the controller, and the negation circuit is used for negating the driving signal and sending the negated driving signal to the third end of the clamping switch tube, so that the clamping switch tube is kept on when the driving switch tube is turned off. By adopting the bridge circuit, the two ends of the driving switch tube can be clamped in time to absorb crosstalk, the crosstalk elimination effect is good, and the working reliability of the switch tube in the bridge circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a bridge circuit and a switching power supply. Background Art

[0002] As an important component of switching power supplies, bridge circuits are mostly used in rectification, inversion and other links. Bridge circuits usually include multiple bridge arms, each of which includes an upper switch tube and a lower switch tube connected in series. When the switching frequency of the switch tube corresponding to the driving signal in the bridge circuit is high, during the opening process of one switch tube on the bridge arm, a positive or negative voltage spike will be generated on another switch tube on the bridge arm. This phenomenon is called crosstalk. Severe positive voltage crosstalk can easily cause the switch tube to be mis-conducted, affecting the working stability of the switch tube, and severe negative voltage crosstalk spikes can easily cause the gate of the switch tube to be broken down and damaged. Therefore, filtering and eliminating crosstalk are of great significance to improving the working reliability of the switch tube in the bridge circuit. In the existing crosstalk elimination scheme, since the crosstalk absorption circuit is not decoupled from the switch tube driving circuit, it is very easy to cause damage to the clamping switch tube in the crosstalk absorption circuit, and the absorption circuit is not enabled in time, resulting in the inability to completely absorb the crosstalk, the crosstalk elimination effect is poor, and the working reliability of the switch tube in the bridge circuit is low. Summary of the invention

[0003] The embodiments of the present application provide a bridge circuit and a switching power supply, which can timely clamp the two ends of the driving switch tube to absorb crosstalk, have a good crosstalk elimination effect, and improve the working reliability of the switch tube in the bridge circuit.

[0004] In the first aspect, the present application provides a bridge circuit, characterized in that the bridge circuit includes at least one bridge arm and at least one anti-crosstalk circuit, the bridge arm includes two driving switch tubes connected in series, the anti-crosstalk circuit includes an inversion circuit and a clamping switch tube, the first end of the driving switch tube is connected to the controller and the first end of the clamping switch tube, the second end of the driving switch tube is connected to the second end of the clamping switch tube, and the second end of the driving switch tube is an end connected to the cathode of the diode in the driving switch tube. The first end of the driving switch tube and the inversion circuit are used to receive a driving signal sent by the controller, the inversion circuit is used to invert the driving signal, and send the inverted driving signal to the third end of the clamping switch tube, so that the clamping switch tube remains turned on when the driving switch tube is turned off.

[0005] In the present application, the first end of the driving switch tube in the bridge circuit and the inversion circuit can receive a driving signal from the controller, the inversion circuit can invert the received driving signal, and send the inverted driving signal to the third end of the clamping switch tube. The clamping switch tube can be turned on or off based on the inverted driving signal, so that the clamping switch tube remains turned on when the driving switch tube is turned off to clamp the first end and the second end of the above-mentioned driving switch tube, and the potential difference between the first end and the second end of the driving switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the driving switch tube due to the conduction of another connected driving switch tube. The clamping switch tube in the anti-crosstalk circuit can timely clamp the two ends of the driving switch tube to absorb crosstalk by multiplexing the driving signal sent by the controller, and the crosstalk elimination effect is good, which improves the working reliability of the switch tube in the bridge circuit.

[0006] In combination with the first aspect, in a first possible implementation, the inversion circuit includes a first resistor and an inversion switch tube, the first end of the inversion switch tube is connected to the first DC power supply and the third end of the clamp switch tube, the second end of the inversion switch tube is connected to the second end of the clamp switch tube, and the third end of the inversion switch tube is connected to the controller through the first resistor. The inversion switch tube is used to invert based on the drive signal and send the inverted drive signal to the third end of the clamp switch tube. The clamp switch tube can be turned on or off based on the inverted drive signal, so that the clamp switch tube remains turned on when the drive switch tube is turned off to clamp the first end and the second end of the above-mentioned drive switch tube, and the potential difference between the first end and the second end of the drive switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the drive switch tube due to the conduction of another connected drive switch tube.

[0007] In combination with the first aspect, in a second possible implementation, the inversion circuit includes a comparator, a non-inverting input terminal of the comparator is connected to a second DC power supply, an inverting input terminal of the comparator is connected to a controller, and an output terminal of the comparator is connected to a third terminal of the clamp switch tube. The comparator is used to invert based on the drive signal, and send the inverted drive signal to the third terminal of the clamp switch tube. The clamp switch tube can be turned on or off based on the inverted drive signal, so that the clamp switch tube remains turned on when the drive switch tube is turned off to clamp the first and second terminals of the above-mentioned drive switch tube, and the potential difference between the first and second terminals of the drive switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the drive switch tube due to the conduction of another connected drive switch tube.

[0008] In combination with the first aspect, in a third possible implementation, the anti-crosstalk circuit further includes a delay circuit, which is used to delay the inverted drive signal and send it to the third end of the clamp switch tube, so that the clamp switch tube and the drive switch tube keep one switch tube turned on and the other switch tube turned off. The delayed inverted drive signal may include a rising edge delay and a falling edge delay for the inverted drive signal, and the clamp switch tube is delayed to turn on and off based on the delayed inverted drive signal, thereby avoiding the clamp switch tube and the drive switch tube from being turned on or off at the same time, and preventing the short circuit phenomenon caused by the clamp switch tube and the drive switch tube being turned on or off at the same time to damage the components in the anti-crosstalk circuit.

[0009] In combination with the third possible implementation of the first aspect, in a fourth possible implementation, the inversion circuit includes a first resistor and an inversion switch tube, the delay circuit includes a first delay resistor, a second delay resistor and a delay capacitor, the first end of the inversion switch tube is connected to the first DC power supply through the first delay resistor, the first end of the inversion switch tube is connected to the third end of the clamp switch tube through the second delay resistor, the second end of the inversion switch tube is connected to the second end of the clamp switch tube, the third end of the inversion switch tube is connected to the controller through the first resistor, and the delay capacitor is connected between the second end of the clamp switch tube and the third end of the clamp switch tube. The first delay resistor, the second delay resistor and the delay capacitor are used to delay the inverted drive signal. The delayed inversion drive signal may include a rising edge delay and a falling edge delay of the inversion drive signal, and the clamp switch tube is delayed to turn on and off based on the delayed inversion drive signal, so as to avoid the clamp switch tube and the drive switch tube from being turned on or off at the same time, and prevent the short circuit phenomenon caused by the clamp switch tube and the drive switch tube being turned on or off at the same time to damage the components in the anti-crosstalk circuit.

[0010] In combination with the third possible implementation of the first aspect, in a fifth possible implementation, the inversion circuit includes a comparator, the delay circuit includes a first delay resistor, a second delay resistor and a delay capacitor, the in-phase input end of the comparator is connected to the second DC power supply, the inverting input end of the comparator is connected to the controller through the first delay resistor, and the second delay resistor and the delay capacitor are respectively connected between the inverting input end of the comparator and the second end of the clamp switch tube. The first delay resistor, the second delay resistor and the delay capacitor are used to delay the inverted drive signal. The delayed inverted drive signal may include a rising edge delay and a falling edge delay for the inverted drive signal, and the clamp switch tube is delayed to turn on and off based on the delayed inverted drive signal, thereby avoiding the clamp switch tube and the drive switch tube from being turned on or off at the same time, and preventing the short circuit phenomenon caused by the clamp switch tube and the drive switch tube being turned on or off at the same time to damage the components in the anti-crosstalk circuit.

[0011] In combination with any one of the first aspect to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the anti-crosstalk circuit also includes a second resistor and a first capacitor connected in series, the second resistor and the first capacitor connected in series are connected in parallel to the first end and the second end of the clamp switch tube, and the second resistor and the first capacitor connected in series are used to absorb the spike voltage when the clamp switch tube switches state, so as to avoid the clamp switch tube being damaged by the spike voltage when the state is switched.

[0012] In combination with any one of the first possible implementation manner of the first aspect to the sixth possible implementation manner of the first aspect, in a seventh possible implementation manner, the clamping switch tube, the inverting switch tube and the driving switch tube are MOS tubes, the first end of the clamping switch tube and the inverting switch tube is a drain, the second end is a source, and the third end is a gate, and the first end of the driving switch tube is a gate, the second end is a source, and the third end is a drain. Alternatively, the clamping switch tube, the inverting switch tube and the driving switch tube are IGBT tubes, the first end of the clamping switch tube and the inverting switch tube is a collector, the second end is an emitter, and the third end is a gate, and the first end of the driving switch tube is a gate, the second end is an emitter, and the third end is a collector.

[0013] In a second aspect, the present application provides a switching power supply, characterized in that the switching power supply includes a DC transformer unit and an inverter unit, and the DC transformer unit or the inverter unit includes the bridge circuit provided by the above-mentioned first aspect and any possible implementation method of the first aspect.

[0014] In the present application, the bridge circuit in the switching power supply may include at least one bridge arm and at least one anti-crosstalk circuit. The bridge arm in the bridge circuit may include a driving switch tube (which may be a MOS tube, an IGBT tube, etc.) connected in series, and each driving switch tube may be connected to an anti-crosstalk circuit. The above-mentioned anti-crosstalk circuit may include an inversion circuit and a clamping switch tube, the first end of the driving switch tube may be connected to the controller in the switching power supply and the first end of the clamping switch tube, and the second end of the driving switch tube (which may be the end connected to the cathode of the diode in the driving switch tube) is connected to the second end of the clamping switch tube. Here, the above-mentioned controller can send a driving signal to the first end of the driving switch tube and the inversion circuit, and the inversion circuit can invert the received driving signal and send the inverted driving signal to the third end of the clamping switch tube. The clamp switch tube can be turned on or off based on the inverted driving signal, so that the clamp switch tube remains on when the driving switch tube is turned off to clamp the first end and the second end of the driving switch tube, and the potential difference between the first end and the second end of the driving switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the driving switch tube due to the connected driving switch tube being turned on. The clamp switch tube in the anti-crosstalk circuit can timely clamp the two ends of the driving switch tube to absorb crosstalk through the driving signal sent by the multiplexing controller, and the crosstalk elimination effect is good, which improves the working reliability of the switch tube in the bridge circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of an application scenario of the power grid power supply system provided by this application;

[0016] Figure 2 It is a structural schematic diagram of the power grid power supply system provided by the present application;

[0017] Figure 3 is another structural schematic diagram of the power grid power supply system provided by the present application;

[0018] Figure 4 It is a structural schematic diagram of a bridge circuit provided by the present application;

[0019] Figure 5 is another structural schematic diagram of the bridge circuit provided by the present application;

[0020] Figure 6 is another structural schematic diagram of the bridge circuit provided by the present application;

[0021] Figure 7 is another structural schematic diagram of the bridge circuit provided by the present application;

[0022] Figure 8 It is a switch tube control timing diagram of the driving signal provided by the present application;

[0023] Fig. 9 is another switch tube control timing diagram of the drive signal provided by the present application;

[0024] Fig.10 It is a structural schematic diagram of a half-bridge circuit provided by the present application;

[0025] Fig.11 It is a structural schematic diagram of a three-phase bridge circuit provided in this application. DETAILED DESCRIPTION

[0026] See also Figure 1 , Figure 1 Schematic diagram of the application scenario of the power grid power supply system provided in this application. The power grid power supply system provided in this application may include a DC power supply and a switching power supply, wherein the DC power supply may be composed of a photovoltaic array, the output end of the photovoltaic array may be connected to the first end of the switching power supply, and the second end of the switching power supply is connected to the AC grid. Figure 1 In the DC power conversion system shown, the photovoltaic array can be composed of one or more photovoltaic strings connected in parallel, and a photovoltaic string can be obtained by connecting one or more photovoltaic modules in series. The switching power supply can change (can be boosted, bucked, etc.) the DC power provided by the photovoltaic array, and perform voltage inversion conversion on the transformed DC power to power the battery, communication base station or household appliances in the AC power grid.

[0027] In some possible implementations, please refer again to Figure 1 The DC power supply may also include an energy storage battery, the output end of which may be connected to the first end of the switching power supply, and the second end of which may be connected to the AC power grid. The switching power supply may change (increase or decrease voltage, etc.) the DC power provided by the energy storage battery, and perform voltage inversion conversion on the transformed DC power to supply power to power batteries, communication base stations, household appliances, and other electrical appliances in the AC power grid.

[0028] In some possible implementations, Figure 1 The switching power supply in the device can perform voltage rectification and conversion on the AC voltage of the AC power grid, and perform DC voltage conversion on the rectified DC power, and then output a DC voltage or a DC current to the energy storage battery. The energy storage battery is charged based on the voltage or current output by the switching power supply.

[0029] exist Figure 1 In the application scenario shown, the switching power supply may include a bridge circuit. During the operation of the switching power supply, the switching power supply may perform current rectification or inversion conversion through the bridge circuit. The bridge circuit generally includes multiple bridge arms, and each bridge arm may include an upper switch tube and a lower switch tube connected in series. The switch tube in the bridge circuit may be turned on or off based on the received drive signal. In the case where the switching frequency of the switch tube corresponding to the drive signal in the bridge circuit is high, during the conduction of a switch tube on any bridge arm, a positive or negative voltage spike will be generated on another switch tube on the bridge arm. This phenomenon is called crosstalk. Severe positive voltage crosstalk can easily cause the switch tube to be mis-conducted, affecting the working stability of the switch tube, while severe negative voltage crosstalk spikes can easily cause the gate of the switch tube to be broken down and damaged. In the conventional switch tube crosstalk elimination scheme, since the crosstalk absorption circuit is not decoupled from the circuit driving the switch tube, it is very easy to cause damage to the switch tube used for clamping in the crosstalk absorption circuit. Alternatively, the switch tube used for clamping requires a separate drive signal to enable, resulting in the crosstalk absorption circuit being untimely enabled and unable to completely absorb the crosstalk, resulting in poor crosstalk elimination effect and low operating reliability of the switch tube in the bridge circuit.

[0030] In the power grid power supply system provided by the present application, the bridge circuit in the switching power supply may include at least one bridge arm and at least one anti-crosstalk circuit, and each bridge arm may include two driving switch tubes connected in series (which may be metal oxide semiconductor field effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), referred to as MOS tubes, and may also be insulated gate bipolar transistors (Insu l ated gate bipolar transistor, IGBT), etc.). Specifically, the above-mentioned anti-crosstalk circuit may include an inversion circuit and a clamping switch tube, and the first end of any driving switch tube in each bridge arm may be connected to the controller in the switching power supply and the first end of the clamping switch tube, and the second end of the driving switch tube (which may be the end connected to the cathode of the diode in the driving switch tube) is connected to the second end of the clamping switch tube. Here, the controller in the above-mentioned switching power supply can send a driving signal to the first end of the driving switch tube and the inversion circuit, and the inversion circuit can invert the received driving signal and send the inverted driving signal to the third end of the clamping switch tube. The clamp switch tube can be turned on or off based on the inverted driving signal, so that the clamp switch tube remains turned on when the driving switch tube is turned off to clamp the first end and the second end of the driving switch tube, and the potential difference between the first end and the second end of the driving switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the driving switch tube due to the conduction of another connected driving switch tube. The clamp switch tube in the anti-crosstalk circuit can timely clamp the two ends of the driving switch tube to absorb crosstalk through the driving signal sent by the multiplexing controller, and the crosstalk elimination effect is good, which improves the working reliability of the switch tube in the bridge circuit.

[0031] See also Figure 2 , Figure 2 Schematic diagram of a power grid power supply system provided by this application. Figure 2 The grid power supply system shown includes a DC power supply and a switching power supply, wherein the power supply can be a solar panel, a storage battery, etc. The input end of the switching power supply is coupled to the DC power supply in the grid power supply system, and the output end of the switching power supply is coupled to the AC grid. Figure 2 In the grid power supply system shown, the switching power supply may include a controller ( Figure 2 The power supply is used to provide a DC input for the switching power supply, and the switching power supply performs a DC power conversion through the DC transformer unit based on the DC input provided by the DC power supply, and performs an inversion conversion on the DC power after the DC power conversion through the inverter unit, and outputs the AC power obtained after the inversion conversion to the AC power grid to supply power to the AC power grid.

[0032] In some possible implementations, Figure 2 In the grid power supply system shown in FIG. 1 , the DC transformer unit and the inverter unit may include a bridge circuit. Figure 3 , Figure 3 is another structural schematic diagram of the power grid power supply system provided by the present application, Figure 3 The grid power supply system shown includes a DC power supply and a switching power supply, wherein the DC transformer in the switching power supply may include a bridge circuit. The DC transformer may include two bridge arms, one bridge arm includes two driving switch tubes connected in series (for the convenience of description, they may be represented as switch tube S1 and switch tube S2), and the other bridge arm includes two driving switch tubes connected in series (for the convenience of description, they may be represented as switch tube S3 and switch tube S4).

[0033] In some possible implementations, Figure 2 or Figure 3 In the grid power supply system shown in the figure, the bridge circuit in the switching power supply may include at least one bridge arm and at least one anti-crosstalk circuit. Figure 3 Take the power grid system shown in the figure as an example. Figure 3 Each driving switch tube (switch tube S1, switch tube S2, switch tube S3 and switch tube S4) in the DC transformer unit can be connected to an anti-crosstalk circuit ( Figure 3 The switch tube S2 is connected to an anti-crosstalk circuit as an example for explanation. The anti-crosstalk circuit may include an inversion circuit and a clamping switch tube. The first end of the switch tube S2 in the DC transformer unit may be connected to a controller ( Figure 3 The controller may be configured to connect the first end of the switch tube S2 and the inverting circuit, and the inverting circuit may be configured to invert the received driving signal and send the inverted driving signal to the third end of the clamping switch tube. The clamping switch tube may be turned on or off based on the inverted driving signal, so that the clamping switch tube remains turned on when the switch tube S2 is turned off to clamp the first end and the second end of the switch tube S2, and the potential difference between the first end and the second end of the switch tube S2 is zero, thereby eliminating the positive or negative voltage spike generated by the switch tube S2 due to the connected switch tube S1 being turned on. The clamping switch tube in the anti-crosstalk circuit can timely clamp the two ends of the driving switch tube to absorb crosstalk by multiplexing the driving signal sent by the controller, and the crosstalk elimination effect is good, which improves the working reliability of the switch tube in the bridge circuit.

[0034] The following will be combined Figures 4 to 11The switching power supply provided in the embodiment of the present application is illustrated. In some feasible implementations, the bridge circuit in the switching power supply (which may be a bridge circuit for DC conversion or inversion) may include at least one bridge arm and at least one anti-crosstalk circuit, the bridge arm may include two driving switch tubes connected in series, and the anti-crosstalk circuit may include an inversion circuit and a clamping switch tube. The first end of the driving switch tube may be connected to the controller in the switching power supply and the first end of the clamping switch tube, the second end of the driving switch tube may be connected to the second end of the clamping switch tube, and the second end of each driving switch tube is an end connected to the cathode of the diode in the driving switch tube. Specifically, the inversion circuit in the anti-crosstalk circuit may include a first resistor and an inversion switch tube, the first end of the inversion switch tube may be connected to the first DC power supply and the third end of the clamping switch tube, the second end of the inversion switch tube may be connected to the second end of the clamping switch tube, and the third end of the inversion switch tube may be connected to the controller through the first resistor. Please refer to Figure 4 , Figure 4 Schematic diagram of a bridge circuit provided by the present application. Figure 4 As shown, Figure 4 The bridge circuit in the embodiment may include two bridge arms, and the driving switch tube in the bridge arm is a MOS tube for example. One bridge arm includes two driving switch tubes connected in series (for the convenience of description, they can be represented as switch tube S1 and switch tube S2), and the other bridge arm includes two driving switch tubes connected in series (for the convenience of description, they can be represented as switch tube S3 and switch tube S4). For example, the bridge circuit includes an anti-crosstalk circuit and the anti-crosstalk circuit is connected to the switch tube S2. The anti-crosstalk circuit may include an inversion circuit and a clamping switch tube (for the convenience of description, it can be represented as switch tube Q1). The first end of the switch tube S2 (which can be the gate of the switch tube S2) can be connected to the controller in the switching power supply and the first end of the switch tube Q1 (which can be the drain of the switch tube Q1), and the second end of the switch tube S2 (which can be the end connected to the cathode of the diode in the switch tube S2, that is, the source of the switch tube S2) is connected to the second end of the switch tube Q1 (which can be the source of the switch tube Q1). Figure 4The inversion circuit of the anti-crosstalk circuit may include a first resistor (for convenience of description, it can be represented as a resistor R11) and an inversion switch tube (for convenience of description, it can be represented as a switch tube Q2), the first end of the switch tube Q2 (which can be the drain of the switch tube Q2) can be connected to a first DC power supply (for example, it can be a DC power supply with a voltage value of at least 5V) and the third end of the above-mentioned switch tube Q1 (which can be the gate of the switch tube Q1), the second end of the switch tube Q2 (which can be the source of the switch tube Q2) can be connected to the source of the switch tube Q1, and the third end of the switch tube Q2 (which can be the gate of the switch tube Q2) can be connected to the controller through the resistor R11. Here, the controller in the switching power supply can send a drive signal to the first end of the switch tube S2 and the inversion circuit (which can include the switch tube Q2 and the resistor R11), the switch tube Q2 and the resistor R11 can invert the drive signal, and send the inverted drive signal to the third end of the switch tube Q1. When the driving signal is at a low level, the switch tube S2 is turned off and the switch tube Q1 is turned on, that is, the switch tube Q1 can remain turned on when the switch tube S2 is turned off to clamp the first end and the second end of the switch tube S2, and the potential difference between the first end and the second end of the switch tube S2 is zero, thereby eliminating the positive or negative voltage spike generated by the switch tube S2 due to the connected switch tube S1 being turned on. Here, the process of eliminating the crosstalk of the corresponding switch tube when the above-mentioned anti-crosstalk circuit is connected to other switch tubes (switch tube S1, switch tube S3 or switch tube S4) in the bridge circuit can refer to the above-mentioned Figure 4 The description of the bridge circuit shown in will not be repeated here. The circuit connection when the driving switch tube of the bridge arm in the bridge is an IGBT tube is similar to the circuit connection when the driving switch tube is a MOS tube. It can be understood that if the switch tubes Q1, Q2 and S2 are IGBT tubes, the first ends of the switch tubes Q1 and Q2 are collectors, the second ends are emitters, and the third ends are gates, and the first ends of the switch tubes S2 are gates, the second ends are emitters, and the third ends are collectors, that is, the first ends, second ends and third ends of each switch tube can be determined according to the specific device type, and are not limited here.

[0035] In some feasible implementations, the inversion circuit in the anti-crosstalk circuit may include a comparator. Specifically, the in-phase input terminal of the comparator may be connected to the second DC power supply, the inverting input terminal of the comparator may be connected to the controller, and the output terminal of the comparator may be connected to the third terminal of the clamp switch tube. Figure 5 , Figure 5 is another structural schematic diagram of the bridge circuit provided by the present application. Figure 5 As shown, Figure 5The bridge circuit in the embodiment may include two bridge arms, and the driving switch tube in the bridge arm is a MOS tube for example. One bridge arm includes two driving switch tubes connected in series (for the convenience of description, they can be represented as switch tube S1 and switch tube S2), and the other bridge arm includes two driving switch tubes connected in series (for the convenience of description, they can be represented as switch tube S3 and switch tube S4). For example, the bridge circuit includes an anti-crosstalk circuit and the anti-crosstalk circuit is connected to the switch tube S2. The anti-crosstalk circuit may include an inversion circuit and a clamping switch tube (for the convenience of description, it can be represented as switch tube Q1). The first end of the switch tube S2 (which can be the gate of the switch tube S2) can be connected to the controller in the switching power supply and the first end of the switch tube Q1 (which can be the drain of the switch tube Q1), and the second end of the switch tube S2 (which can be the end connected to the cathode of the diode in the switch tube S2, that is, the source of the switch tube S2) is connected to the second end of the switch tube Q1 (which can be the source of the switch tube Q1). Figure 5 The inversion circuit of the anti-crosstalk circuit may include a comparator K1 (which may be a single-power comparator), and the in-phase input terminal of the comparator K1 may be connected to a second DC power supply, where the voltage value of the second DC power supply may be lower than the peak value of the high-level voltage of the drive signal (which may be 5v), such as 2.5v. The inverting input terminal of the comparator K1 may be connected to a controller, and the output terminal of the comparator may be connected to the third terminal of the switch tube Q1 (which may be the gate of the switch tube Q1). Here, the controller in the switching power supply may send a drive signal to the first terminal of the switch tube S2 and the inversion circuit (which may include a comparator K1), and the comparator K1 may invert the drive signal input to the inverting input terminal, and send the inverted drive signal to the third terminal of the switch tube Q1. When the driving signal is at a low level, the switch tube S2 is turned off and the switch tube Q1 is turned on, that is, the switch tube Q1 can remain turned on when the switch tube S2 is turned off to clamp the first end and the second end of the switch tube S2, and the potential difference between the first end and the second end of the switch tube S2 is zero, thereby eliminating the positive or negative voltage spike generated by the switch tube S2 due to the connected switch tube S1 being turned on. Here, the process of eliminating the crosstalk of the corresponding switch tube when the above-mentioned anti-crosstalk circuit is connected to other switch tubes (switch tube S1, switch tube S3 or switch tube S4) in the bridge circuit can refer to the above-mentioned Figure 4 The description of the bridge circuit shown in is not repeated here. The circuit connection when the driving switch tube of the bridge arm in the bridge is an IGBT tube is similar to the circuit connection when the driving switch tube is a MOS tube, and is not repeated here.

[0036] In some feasible implementations, the anti-crosstalk circuit includes a delay circuit, which can delay the inverted drive signal and send it to the third terminal of the clamp switch tube in the anti-crosstalk circuit. Specifically, the delay circuit can include a first delay resistor, a second delay resistor and a delay capacitor. For example, the above Figure 4The anti-crosstalk circuit in the embodiment may further include a delay circuit, which may include a first delay resistor, a second delay resistor and a delay capacitor. Figure 6 , Figure 6 is another structural schematic diagram of the bridge circuit provided by the present application. Figure 6 As shown, Figure 6 The bridge circuit in the embodiment may include two bridge arms, and the driving switch tube in the bridge arm is a MOS tube for example. One bridge arm includes a switch tube S1 and a switch tube S2 connected in series, and the other bridge arm includes a switch tube S3 and a switch tube S4 connected in series. For example, the bridge circuit includes an anti-crosstalk circuit and the anti-crosstalk circuit is connected to the switch tube S2. The anti-crosstalk circuit may include an inversion circuit, a delay circuit, and a clamping switch tube (for convenience of description, it may be represented as a switch tube Q1). The gate of the switch tube S2 may be connected to the controller in the switching power supply and the drain of the switch tube Q1, and the source of the switch tube S2 may be connected to the source of the switch tube Q1. Figure 4 The inversion circuit of the anti-crosstalk circuit may include a first resistor (for convenience of description, it can be represented as a resistor R11) and an inversion switch tube (for convenience of description, it can be represented as a switch tube Q2), and the delay circuit may include a first delay resistor (for convenience of description, it can be represented as a resistor R21), a second delay resistor (for convenience of description, it can be represented as a resistor R22) and a delay capacitor (for convenience of description, it can be represented as a capacitor C11). The drain of the switch tube Q2 can be connected to the first DC power supply through the resistor R21, the drain of the switch tube Q2 can be connected to the gate of the clamping switch tube Q1 through the resistor R22, the source of the switch tube Q2 is connected to the source of the switch tube Q1, the gate of the switch tube Q2 is connected to the controller through the resistor R11, and the capacitor C11 is connected between the gate and the source of the switch tube Q1. Here, the controller in the switching power supply can send a driving signal to the first end of the switch tube S2, the inversion circuit (which may include a comparator K1) and the delay circuit (which may include a resistor R21, a resistor R22 and a capacitor C11). The above-mentioned inversion circuit and the delay circuit can respectively invert and delay the driving signal to obtain a delayed inverted driving signal. The above-mentioned delayed inverted driving signal may include a rising edge delay and a falling edge delay of the inverted driving signal. The switch tube Q1 is delayed to be turned on and delayed to be turned off based on the delayed inverted driving signal, thereby avoiding the switch tube Q1 and the switch tube S2 from being turned on or off at the same time, and preventing the short circuit phenomenon caused by the switch tube Q1 and the switch tube S2 being turned on or off at the same time from damaging the devices in the anti-crosstalk circuit.

[0037] In some feasible implementations, the above Figure 5 The anti-crosstalk circuit in the embodiment may further include a delay circuit, which may include a first delay resistor, a second delay resistor and a delay capacitor. Figure 7 , Figure 7is another structural schematic diagram of the bridge circuit provided by the present application. Figure 7 As shown, Figure 7 The bridge circuit in the embodiment may include two bridge arms, and the driving switch tube in the bridge arm is a MOS tube for example. One bridge arm includes a switch tube S1 and a switch tube S2 connected in series, and the other bridge arm includes a switch tube S3 and a switch tube S4 connected in series. For example, the bridge circuit includes an anti-crosstalk circuit and the anti-crosstalk circuit is connected to the switch tube S2. The anti-crosstalk circuit may include an inversion circuit, a delay circuit, and a clamping switch tube (for convenience of description, it may be represented as a switch tube Q1). The gate of the switch tube S2 may be connected to the controller in the switching power supply and the drain of the switch tube Q1, and the source of the switch tube S2 may be connected to the source of the switch tube Q1. Figure 5 The inversion circuit of the anti-crosstalk circuit may include a comparator K1, and the delay circuit may include a first delay resistor (for convenience of description, it can be represented as a resistor R21), a second delay resistor (for convenience of description, it can be represented as a resistor R22) and a delay capacitor (for convenience of description, it can be represented as a capacitor C11). The in-phase input terminal of the comparator K1 can be connected to the second DC power supply, the inverting input terminal of the comparator can be connected to the controller through the resistor R21, and the resistor R22 and the capacitor C11 can be connected between the inverting input terminal of the comparator K1 and the source of the switch tube Q1, respectively. Here, the controller in the switching power supply can send a driving signal to the first end of the switch tube S2, the inversion circuit (which may include a comparator K1) and the delay circuit (which may include a resistor R21, a resistor R22 and a capacitor C11). The above-mentioned inversion circuit and the delay circuit can respectively invert and delay the driving signal to obtain a delayed inverted driving signal. The above-mentioned delayed inverted driving signal may include a rising edge delay and a falling edge delay of the inverted driving signal. The switch tube Q1 is delayed to be turned on and delayed to be turned off based on the delayed inverted driving signal, thereby avoiding the switch tube Q1 and the switch tube S2 from being turned on or off at the same time, and preventing the short circuit phenomenon caused by the switch tube Q1 and the switch tube S2 being turned on or off at the same time from damaging the devices in the anti-crosstalk circuit.

[0038] In some feasible implementations, the above Figure 7 The anti-crosstalk circuit in the bridge circuit shown may also include a resistor R31 and a resistor R32 for adjusting the trigger threshold of the switch tube Q1 (such as the conduction threshold of the switch tube Q1), one end of the resistor R31 may be connected to the above-mentioned second DC power supply, the other end of the resistor R31 may be connected to the in-phase input end of the comparator K1, and the two ends of the resistor R32 may be connected to the in-phase input end and the output end of the comparator K1 respectively. The anti-crosstalk circuit may also include a resistor R33 for current limiting, one end of the resistor R33 may be connected to the output end of the comparator K1, and the other end of the resistor R33 may be connected to the third end of the switch tube Q1.

[0039] For some possible implementations, please refer to Figure 8 , Figure 8 is a switch control timing diagram of the drive signal provided by the present application. Figure 8 As shown, Figure 8 Including the driving signal received by the switch tube S2 and the driving signal received by the switch tube S1 (connected in series with the switch tube S2 to form a bridge arm). The above switch tubes S1 and S2 are alternately turned on based on the received driving signals. Specifically, during the conduction of the switch tube S1 on the bridge arm, a positive or negative voltage spike will be generated in the turned-off switch tube S2, affecting the normal operation of the switch tube S2 or even damaging the switch tube S2. Please refer to Fig. 9 , Fig. 9 is another switch control timing diagram of the drive signal provided by the present application. Fig. 9 As shown, Fig. 9 The drive signal includes the drive signal received by the switch tube S2, the drive signal received by the switch tube S1 (which is connected in series with the switch tube S2 to form a bridge arm), and the drive signal received by the switch tube Q1 (which can be the above Figure 6 or Figure 7 The switch tube Q1 of the anti-crosstalk circuit is alternately turned on based on the received driving signal. The switch tube Q1 receives the driving signal after being inverted by the inversion circuit and delayed by the delay circuit. The driving signal received by the gate of the switch tube Q1 is complementary to the driving signal received by the switch tube S2, that is, the switch tube Q1 can remain turned on when the switch tube S2 is turned off to clamp the first end and the second end of the switch tube S2. The potential difference between the first end and the second end of the switch tube S2 is zero, thereby eliminating the positive or negative voltage spike of the switch tube S2 caused by the connected switch tube S1 being turned on. In addition, the driving signal received by the gate of the switch tube Q1 is turned on and off with delay, so as to avoid the switch tube Q1 and the switch tube S2 from being turned on or off at the same time, and to prevent the short circuit phenomenon caused by the switch tube Q1 and the switch tube S2 being turned on or off at the same time to damage the components in the anti-crosstalk circuit, thereby improving the reliability of the switch tube in the bridge circuit.

[0040] In some feasible implementations, the anti-crosstalk circuit includes a second resistor and a first capacitor connected in series, and the second resistor and the first capacitor connected in series are connected in parallel to the first end and the second end of the clamp switch tube. Figure 4 Take the bridge circuit in as an example, Figure 4The anti-crosstalk circuit of the mid-bridge circuit includes a second resistor (for the convenience of description, it can be expressed as resistor R12) and a first capacitor (for the convenience of description, it can be expressed as capacitor C12) connected in series. One end of the resistor R12 is connected to the drain of the switch tube Q1, and one end of the capacitor C12 is connected to the source of the switch tube Q1. Here, the series resistor R12 and capacitor C12 can absorb the spike voltage when the state of the switch tube Q1 is switched (for example, the switch tube Q1 is switched from on to off, or the switch tube Q1 is switched from off to on), so as to prevent the switch tube Q1 from being damaged by the spike voltage when the state is switched. It can be understood that the above Figure 5 To the above Figure 7 The anti-crosstalk circuit in the embodiment may include a second resistor and a first capacitor connected in series, and the connection relationship between the second resistor and the first capacitor is Figure 4 The anti-crosstalk circuit in is similar and will not be described here.

[0041] In some feasible implementations, the bridge circuit in the above-mentioned switching power supply (which may be a bridge circuit for DC conversion or for inverter conversion) may include a half-bridge. Please refer to Fig.10 , Fig.10 It is a schematic diagram of the structure of a half-bridge circuit. Fig.10 The bridge circuit shown may include one bridge arm, which includes two driving switch tubes connected in series (for the convenience of description, they can be represented as switch tube S1 and switch tube S2). The bridge circuit in the above switching power supply (which can be a bridge circuit for DC conversion or for inverter conversion) can include a three-phase bridge. Please refer to Fig.11 , Fig.11 It is a structural diagram of a three-phase bridge circuit. Fig.11 The bridge circuit shown may include three bridge arms, wherein the first bridge arm includes two driving switch tubes connected in series (for the convenience of description, they may be represented as switch tube S1 and switch tube S2), the second bridge arm includes two driving switch tubes connected in series (for the convenience of description, they may be represented as switch tube S3 and switch tube S4), and the third bridge arm includes two driving switch tubes connected in series (for the convenience of description, they may be represented as switch tube S5 and switch tube S6). Here, the above Fig.10 or Fig.11 The bridge circuit shown may include at least one anti-crosstalk circuit, and Fig.10 or Fig.11 One or more switch tubes in the bridge circuit shown in the figure can be connected to an anti-crosstalk circuit (the circuit composition and connection method of the anti-crosstalk circuit can be referred to above). Figures 5 to 7In the bridge circuit in FIG, the clamping switch tube in each anti-crosstalk circuit can remain turned on when the corresponding driving switch tube is turned off to clamp the first end and the second end of the driving switch tube, so that the potential difference between the first end and the second end of the driving switch tube is zero, thereby eliminating the positive or negative voltage spike of the driving switch tube caused by the connected driving switch tube being turned on. Here, if the clamping switch tube and the driving switch tube are MOS tubes, the first end of the clamping switch tube is the drain, the second end is the source, and the third end is the gate, and the first end of the driving switch tube is the gate, the second end is the source, and the third end is the drain. If the clamping switch tube, the switch tube Q2 and the driving switch tube are IGBT tubes, the first end of the clamping switch tube is the collector, the second end is the emitter, and the third end is the gate, the first end of the driving switch tube is the gate, the second end is the emitter, and the third end is the collector, that is, the first end, the second end and the third end of each switch tube can be determined according to the specific device type, and no limitation is made here.

[0042] In the present application, the bridge circuit in the switching power supply may include at least one bridge arm and at least one anti-crosstalk circuit. The bridge arm in the bridge circuit may include a driving switch tube (which may be a MOS tube, an IGBT tube, etc.) connected in series, and each driving switch tube may be connected to an anti-crosstalk circuit. The above-mentioned anti-crosstalk circuit may include an inversion circuit and a clamping switch tube, the first end of the driving switch tube may be connected to the controller in the switching power supply and the first end of the clamping switch tube, and the second end of the driving switch tube (which may be the end connected to the cathode of the diode in the driving switch tube) is connected to the second end of the clamping switch tube. Here, the above-mentioned controller can send a driving signal to the first end of the driving switch tube and the inversion circuit, and the inversion circuit can invert the received driving signal and send the inverted driving signal to the third end of the clamping switch tube. The clamp switch tube can be turned on or off based on the inverted driving signal, so that the clamp switch tube remains on when the driving switch tube is turned off to clamp the first end and the second end of the driving switch tube, and the potential difference between the first end and the second end of the driving switch tube is zero, thereby eliminating the positive or negative voltage spike generated by the driving switch tube due to the connected driving switch tube being turned on. The clamp switch tube in the anti-crosstalk circuit can timely clamp the two ends of the driving switch tube to absorb crosstalk through the driving signal sent by the multiplexing controller, and the crosstalk elimination effect is good, which improves the working reliability of the switch tube in the bridge circuit.

Claims

1. A bridge circuit, characterized in that: The bridge circuit includes at least one bridge arm and at least one anti-crosstalk circuit, the bridge arm includes two driving switch tubes connected in series, the anti-crosstalk circuit includes an inversion circuit and a clamping switch tube, the first end of the driving switch tube is connected to the controller and the first end of the clamping switch tube, the second end of the driving switch tube is connected to the second end of the clamping switch tube, and the second end of the driving switch tube is an end connected to the cathode of the diode in the driving switch tube; The first end of the driving switch tube and the inversion circuit are used to receive the driving signal sent by the controller, and the inversion circuit is used to invert the driving signal and send the inverted driving signal to the third end of the clamping switch tube, so that the clamping switch tube remains turned on when the driving switch tube is turned off.

2. The bridge circuit according to claim 1, characterized in that: The inversion circuit comprises a first resistor and an inversion switch tube, wherein the first end of the inversion switch tube is connected to the first DC power supply and the third end of the clamp switch tube, the second end of the inversion switch tube is connected to the second end of the clamp switch tube, and the third end of the inversion switch tube is connected to the controller through the first resistor; The inversion switch tube is used to perform inversion based on the driving signal, and send the inverted driving signal to the third end of the clamping switch tube.

3. The bridge circuit according to claim 1, characterized in that: The negation circuit comprises a comparator, wherein the non-inverting input terminal of the comparator is connected to the second DC power supply, the inverting input terminal of the comparator is connected to the controller, and the output terminal of the comparator is connected to the third terminal of the clamp switch tube; The comparator is used to perform inversion based on the driving signal, and send the inverted driving signal to the third terminal of the clamp switch tube.

4. The bridge circuit according to claim 1, characterized in that: The anti-crosstalk circuit also includes a delay circuit, which is used to delay the inverted drive signal and send it to the third end of the clamp switch tube, so that the clamp switch tube and the drive switch tube keep one switch tube turned on and the other switch tube turned off.

5. The bridge circuit according to claim 4, characterized in that: The inversion circuit includes a first resistor and an inversion switch tube, the delay circuit includes a first delay resistor, a second delay resistor and a delay capacitor, the first end of the inversion switch tube is connected to a first DC power supply through the first delay resistor, the first end of the inversion switch tube is connected to a third end of the clamp switch tube through the second delay resistor, the second end of the inversion switch tube is connected to the second end of the clamp switch tube, the third end of the inversion switch tube is connected to the controller through the first resistor, and the delay capacitor is connected between the second end of the clamp switch tube and the third end of the clamp switch tube; The first delay resistor, the second delay resistor and the delay capacitor are used to delay the inverted driving signal.

6. The bridge circuit according to claim 4, characterized in that: The negation circuit includes a comparator, the delay circuit includes a first delay resistor, a second delay resistor and a delay capacitor, the non-inverting input end of the comparator is connected to the second DC power supply, the inverting input end of the comparator is connected to the controller through the first delay resistor, and the second delay resistor and the delay capacitor are respectively connected between the inverting input end of the comparator and the second end of the clamp switch tube; The first delay resistor, the second delay resistor and the delay capacitor are used to delay the inverted driving signal.

7. The bridge circuit according to any one of claims 1 to 6, characterized in that: The anti-crosstalk circuit also includes a second resistor and a first capacitor connected in series, wherein the second resistor and the first capacitor are connected in parallel to the first end of the clamp switch tube and the second end of the clamp switch tube, and the second resistor and the first capacitor are used to absorb the peak voltage when the clamp switch tube switches state.

8. The bridge circuit according to any one of claims 2 to 7, characterized in that: The clamp switch tube, the inverting switch tube and the driving switch tube are MOS tubes, the first end of the clamp switch tube and the inverting switch tube is a drain, the second end is a source, and the third end is a gate, and the first end of the driving switch tube is a gate, the second end is a source, and the third end is a drain; Alternatively, the clamping switch tube, the inverting switch tube and the driving switch tube are IGBT tubes, the first end of the clamping switch tube and the inverting switch tube is the collector, the second end is the emitter, and the third end is the gate, and the first end of the driving switch tube is the gate, the second end is the emitter, and the third end is the collector.

9. A switching power supply, characterized in that: The switching power supply includes a DC transformer unit and an inverter unit, and the DC transformer unit or the inverter unit includes the bridge circuit according to any one of claims 1 to 8.

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