A power switch driving circuit, method and electrical equipment

Abstract

The present invention discloses a power switch driving circuit, method and electrical equipment. The circuit includes: a first resistor and a second resistor connected in series, the first end of the first resistor is connected to the first output port of the driving chip, and the end of the second resistor is connected to the gate of the power switch; a first switch, whose input end is connected between the first resistor and the second resistor, and whose output end is connected between the second resistor and the gate of the power switch; a control module, whose input end is connected between the second resistor and the gate of the power switch, and whose output end is connected to the control end of the first switch, for controlling the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch. Through the present invention, the switching rate of the power switch can be changed according to the gate voltage of the power switch, and the peak voltage can be suppressed after the peak voltage appears, so as to avoid the power switch from being broken down when the peak voltage appears at the gate, thereby improving reliability and safety.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a power switch driving circuit, method and electrical equipment. Background Art

[0002] In the power conversion equipment of electrical equipment, the power switch (such as the insulated gate bipolar transistor, IGBT) is one of the most core devices, which determines whether the power conversion is carried out normally. However, during the operation of the power switch, the gate voltage is often subject to various interferences, forming a spike voltage, which will cause the risk of the power switch being broken down and damaged. Once the power switch is broken down, the reliability and safety of the entire equipment operation will be reduced.

[0003] With respect to the problem in the prior art that the peak voltage generated by the gate of the power switch causes the power switch to be broken down, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a power switch driving circuit, method, and electrical equipment method and device to solve the problem in the prior art that the peak voltage generated by the gate of the power switch causes the power switch to be broken down.

[0005] In order to solve the above technical problems, the present invention provides a power switch driving circuit, which includes:

[0006] A first resistor and a second resistor are connected in series, the first end of the first resistor is connected to the first output port of the driver chip, and the end of the second resistor is connected to the gate of the power switch;

[0007] a first switch, an input end of which is connected between the first resistor and the second resistor, and an output end of which is connected between the second resistor and the gate of the power switch;

[0008] A control module, whose input end is connected between the second resistor and the gate of the power switch, and whose output end is connected to the control end of the first switch, is used to control the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch to control the value of the driving resistance of the power switch.

[0009] Furthermore, the resistance of the second resistor is greater than the resistance of the first resistor.

[0010] Further, the control module includes a first voltage dividing unit, a second switch, a second voltage dividing unit and a unidirectional element;

[0011] Wherein, the first end of the first voltage dividing unit is connected to the forward bias source, the second end is connected to the input end of the second switch, and the third end is connected to the control end of the first switch;

[0012] The output end of the second switch is connected between the second end of the second voltage dividing unit and the second output port of the driving chip;

[0013] The first end of the second voltage dividing unit is connected to the anode of the unidirectional element, the second end is connected between the emitter of the power switch and the second output port of the driving chip, and the third end is connected to the control end of the second switch;

[0014] The cathode of the unidirectional element is connected between the second resistor and the gate of the power switch.

[0015] Furthermore, the first voltage dividing unit includes:

[0016] A third resistor and a fourth resistor are connected in series at the beginning and the end, the beginning of the third resistor is connected to the forward bias source, the end of the fourth resistor is connected to the input end of the second switch, and the line between the third resistor and the fourth resistor is connected to the control end of the first switch.

[0017] Furthermore, the second voltage dividing unit includes:

[0018] A fifth resistor and a sixth resistor are connected in series at the beginning and the end, the first end of the fifth resistor is connected to the anode of the unidirectional element, the end of the sixth resistor is connected between the emitter of the power switch and the second output port of the driver chip, and the line between the fifth resistor and the sixth resistor is connected to the control end of the second switch.

[0019] Furthermore, the first switch is an N-channel MOS transistor, and the second switch is an NPN transistor.

[0020] Furthermore, the control module further includes:

[0021] A first anti-reverse connection element has an anode connected to the anode of the unidirectional element and a cathode connected to the first end of the second voltage dividing unit.

[0022] Furthermore, the circuit further comprises:

[0023] The second reverse connection protection element has an anode connected to the output end of the first switch and a cathode connected between the second resistor and the gate of the power switch.

[0024] The present invention also provides an electrical device, including a power switch and the power switch driving circuit.

[0025] Furthermore, the electrical equipment includes at least one of the following:

[0026] Air conditioners, washing machines, refrigerators, water heaters, fans, dryers, air purifiers, water purifiers, and water purifiers.

[0027] The present invention also provides a power switch driving method, which is applied to the above power switch driving circuit, and the method comprises:

[0028] Controlling the on / off state of the first switch according to the voltage between the second resistor and the gate of the power switch;

[0029] The value of the driving resistance of the power switch is controlled according to the on-off state of the first switch.

[0030] Further, controlling the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch includes:

[0031] The breakdown state of the unidirectional element is controlled according to the voltage between the second resistor and the gate of the power switch; wherein the cathode of the unidirectional element is connected between the second resistor and the gate of the power switch, and the cathode is connected to the second voltage dividing unit;

[0032] The on-off state of the second switch is controlled according to the breakdown state of the unidirectional element; wherein the control end of the second switch is connected to the second voltage dividing unit, the input end is connected to the first voltage dividing unit, and the voltage dividing unit is connected to the first switch;

[0033] The on / off state of the first switch is controlled according to the on / off state of the second switch.

[0034] Further, controlling the breakdown state of the unidirectional element according to the voltage between the second resistor and the gate of the power switch comprises:

[0035] If the voltage between the second resistor and the gate of the power switch is greater than or equal to a preset threshold, the unidirectional element breaks down;

[0036] If the voltage between the second resistor and the gate of the power switch is less than the preset threshold, the unidirectional element is turned off.

[0037] Further, controlling the on-off state of the second switch according to the breakdown state of the unidirectional element includes:

[0038] If the unidirectional element breaks down, controlling the second switch to be turned on;

[0039] If the unidirectional element is turned off, the second switch is controlled to be turned off.

[0040] Further, controlling the on-off state of the first switch according to the on-off state of the second switch includes:

[0041] If the second switch is turned on, controlling the first switch to be turned off;

[0042] If the second switch is turned off, the first switch is controlled to be turned on.

[0043] Further, controlling the value of the driving resistance of the power switch according to the on-off state of the first switch includes:

[0044] If the first switch is turned on, the driving resistance of the power switch is controlled to be the resistance value of the first resistor;

[0045] If the first switch is turned off, the driving resistance of the power switch is controlled to be the sum of the resistance of the first resistor and the resistance of the second resistor;

[0046] Wherein, the resistance value of the second resistor is greater than the resistance value of the first resistor.

[0047] The present invention also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the power switch driving method is implemented.

[0048] By applying the technical solution of the present invention, a first switch is connected in parallel at both ends of the second resistor in a first resistor and a second resistor arranged in series, and a control module is used to control the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch, thereby controlling the driving resistance value of the power switch to be equal to the resistance value of the first resistor or the sum of the resistance values ​​of the first resistor and the second resistor, thereby changing the driving resistance of the power switch, and then changing the switching rate of the power switch. Through the above solution, the switching rate of the power switch can be changed according to the gate voltage of the power switch, and after the peak voltage occurs, the peak voltage is suppressed to avoid the power switch from being broken down when the peak voltage occurs at the gate, thereby improving reliability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a structural diagram of a power switch driving circuit according to an embodiment of the present invention;

[0050] Figure 2 is a structural diagram of a power switch driving circuit according to another embodiment of the present invention;

[0051] Figure 3 FIG. 4 is a flow chart of a power switch driving method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0054] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0055] It should be understood that although the terms first, second, etc. may be used to describe resistors in embodiments of the present invention, these resistors should not be limited to these terms. These terms are only used to distinguish different resistors. For example, without departing from the scope of embodiments of the present invention, a first resistor may also be referred to as a second resistor, and similarly, a second resistor may also be referred to as a first resistor.

[0056] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0057] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0058] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0059] Example 1

[0060] This embodiment provides a power switch driving circuit. Figure 1 is a structural diagram of a power switch driving circuit according to an embodiment of the present invention, such as Figure 1 As shown, the circuit includes: a first resistor R1 and a second resistor R2 connected in series, the end of the first resistor R1 is connected to the beginning of the second resistor R2 to form a series structure, and at the same time, the beginning of the first resistor R1 and the end of the second resistor R2 can be connected to other components. The beginning of the first resistor R1 is connected to the first output port V of the driver chip IC. O , the end of the second resistor R2 is connected to the gate G of the power switch.

[0061] The power switch driving circuit further includes a first switch Q1, whose input end is connected between the first resistor R1 and the second resistor R2, and whose output end is connected between the second resistor R2 and the gate G of the power switch, that is, the first switch Q1 is arranged in parallel with the second resistor R2;

[0062] The above-mentioned power switch driving circuit also includes a control module 10, whose input end is connected between the second resistor R2 and the gate G of the power switch, and whose output end is connected to the control end of the first switch Q1, and is used to control the on-off state of the first switch Q1 according to the voltage between the second resistor R2 and the gate G of the power switch, so as to control the value of the driving resistance of the power switch, and further control the switching rate of the power switch.

[0063] Specifically, when no spike voltage appears on the gate G of the power switch, the voltage between the second resistor R2 and the gate G of the power switch is less than a preset threshold value, the first switch Q1 is controlled to be turned on, the second resistor R2 is short-circuited, only the first resistor R1 is connected to the circuit, and the value of the driving resistor is equal to the resistance value of the first resistor R1. At this time, due to the small driving resistance, the switching rate of the power switch is relatively high; when a spike voltage appears on the gate G of the power switch, the voltage between the second resistor R2 and the gate G of the power switch is greater than or equal to the preset threshold value, the first switch Q1 is controlled to be turned off, the first resistor R1 and the second resistor R2 are connected to the circuit at the same time, and the value of the driving resistor is equal to the sum of the resistance values ​​of the first resistor R1 and the second resistor R2. At this time, due to the increase in the value of the driving resistor, the switching rate of the power switch is reduced, and the spike voltage is suppressed.

[0064] The power switch driving circuit of the present embodiment connects a first switch in parallel at both ends of the second resistor of the first resistor and the second resistor arranged in series, and controls the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch through a control module, thereby controlling the driving resistance value of the power switch to be equal to the resistance value of the first resistor or the sum of the resistance values ​​of the first resistor and the second resistor, thereby changing the driving resistance of the power switch, and thereby changing the switching rate of the power switch. Through the above scheme, the switching rate of the power switch can be changed according to the gate voltage of the power switch, and after the peak voltage appears, the peak voltage is suppressed to prevent the power switch from being broken down when the peak voltage appears on the gate, thereby improving reliability and safety.

[0065] Example 2

[0066] This embodiment provides another power switch driving circuit. In this embodiment, the resistance of the second resistor R2 is greater than the resistance of the first resistor, so that when the voltage between the second resistor R2 and the gate G of the power switch is greater than or equal to the preset threshold, the driving resistance is increased by a large amplitude, thereby significantly reducing the switching rate of the power switch. However, the resistance of the second resistor R2 cannot be infinite, because the standard of the switching rate under normal conditions needs to be determined according to the dead time of the power switch set in the actual working circuit. When the second resistor R2 is connected to the circuit, the switching rate of the power switch will be reduced, which will shorten the actual dead time. It is necessary to at least ensure that the actual dead time is greater than zero or the minimum dead time required by the actual circuit, otherwise there will be a risk of short circuit damage caused by the simultaneous opening of two power switches. Therefore, when the set dead time is large, the limit resistance of the second resistor R2 can also be correspondingly larger, and when the set dead time is small, the limit resistance of the second resistor R2 can also be correspondingly smaller.

[0067] Figure 2 is a structural diagram of a power switch driving circuit according to another embodiment of the present invention, in order to realize that when the voltage between the second resistor R2 and the gate G of the power switch is less than a preset threshold, the first switch Q1 is controlled to be turned on; when the voltage between the second resistor R2 and the gate G of the power switch is greater than or equal to the preset threshold, the first switch Q1 is controlled to be turned off, as shown in FIG. Figure 2 As shown, the control module 10 includes a first voltage dividing unit 101 , a second switch Q2 , a second voltage dividing unit 102 and a unidirectional element Z.

[0068] Among them, the first end of the above-mentioned first voltage dividing unit 101 is connected to the forward bias source Vcc, the second end of the first voltage dividing unit 101 is connected to the input end of the second switch Q2, the third end of the first voltage dividing unit 101 is connected to the control end of the first switch Q1, and the second voltage dividing unit 102 is used to output a first control voltage to control the first switch Q1 to be turned on or off.

[0069] The output end of the second switch Q2 is connected to the second end of the second voltage dividing unit 102 and the second output port V E The second switch Q2 is used to control the on-off state of the first switch Q1 according to its own on-off state.

[0070] The first end of the second voltage dividing unit 102 is connected to the anode of the unidirectional element Z, and the second end is connected to the emitter E of the power switch and the second output port V of the driver chip IC. E The third end is connected to the control end of the second switch Q2, and the second voltage dividing unit 102 is used to output a second control voltage to control the on or off of the second switch Q2.

[0071] The cathode of the unidirectional element Z is connected between the second resistor R2 and the gate G of the power switch, and is used to control its breakdown state based on the voltage between the second resistor R2 and the gate G of the power switch. In this embodiment, the unidirectional element Z is a breakdown diode.

[0072] When the gate G of the power switch does not have a spike voltage, the voltage between the second resistor R2 and the gate G of the power switch is less than the preset threshold value, the unidirectional element Z is turned off, the second switch Q2 is turned off, and the input voltage of the first switch Q1 is the voltage of the forward bias voltage output by the forward bias source Vcc after being divided by the third resistor R3 in the first voltage divider unit 101. The voltage is relatively high and can control the first switch to be turned on. The second resistor R2 is short-circuited, and only the first resistor R1 is connected to the circuit. The value of the driving resistor is equal to the resistance value of the first resistor R1. At this time, due to the small driving resistance, the power switch The switching rate is relatively high; when a spike voltage appears on the gate G of the power switch, the voltage between the second resistor R2 and the gate G of the power switch is greater than or equal to the preset threshold, the unidirectional element Z breaks down, the second switch Q2 is turned on, the input voltage of the first switch Q1 is pulled down, and the first switch cannot be turned on, so the first switch Q1 is turned off, the first resistor R1 and the second resistor R2 are connected to the circuit at the same time, and the value of the driving resistor is equal to the sum of the resistance values ​​of the first resistor R1 and the second resistor R2. At this time, due to the increase in the driving resistance, the switching rate of the power switch is reduced, and the spike voltage is suppressed. In this embodiment, the preset threshold is set to the breakdown voltage of the unidirectional element Z, that is, when the reverse voltage input to the unidirectional element Z exceeds the preset threshold, the unidirectional element Z will be broken down.

[0073] Since the input voltage of the first switch has a maximum limit, in order to achieve voltage division protection, the first voltage division unit 101 includes: a third resistor R3 and a fourth resistor R4 which are connected in series, the end of the third resistor R3 is connected to the beginning of the fourth resistor R4 to form a series structure, the beginning of the third resistor R4 is connected to the forward bias source Vcc, the end of the fourth resistor R4 is connected to the input end of the second switch Q2, and the line between the third resistor R3 and the fourth resistor R4 is connected to the control end of the first switch Q1.

[0074] Since the input voltage of the second switch also has a maximum limit, in order to achieve the voltage division protection function, the second voltage division unit 102 includes: a fifth resistor R5 and a sixth resistor R6 which are arranged in series, the end of the fifth resistor R5 is connected to the beginning of the sixth resistor R6 to form a series structure, the beginning of the fifth resistor R5 is connected to the anode of the unidirectional element Z, and the end of the sixth resistor R6 is connected to the emitter E of the power switch and the second output port V of the driver chip IC. E A line between the fifth resistor R5 and the sixth resistor R6 is connected to the control end of the second switch.

[0075] Due to the different types and principles of switches that are controlled on and off by voltage, in order to achieve conduction when the unidirectional element breaks down and to be turned off when the unidirectional element is cut off, the second switch Q2 is an NPN-type triode. In order to achieve conduction when the second switch Q2 is turned off and to be turned off when the second switch Q2 is turned on, the first switch is an N-channel MOS tube.

[0076] In order to control the direction of the current and avoid reverse conduction of the current, the above-mentioned control module 10 also includes: a first anti-reverse connection element D1, whose anode is connected to the anode of the unidirectional element Z, and whose cathode is connected to the first end of the second voltage divider unit 102, so as to control the current to flow only along the anode of the unidirectional element Z to the first end of the second voltage divider unit 102.

[0077] Similarly, the power switch driving circuit further includes: a second anti-reverse connection element D2, whose anode is connected to the output end of the first switch Q1, and whose cathode is connected between the second resistor R2 and the gate G of the power switch, so as to control the current to flow only along the output end of the first switch Q1 to between the second resistor R2 and the gate G of the power switch.

[0078] In this embodiment, the first anti-reverse connection element D1 and the second anti-reverse connection element D2 are both diodes.

[0079] Example 3

[0080] This embodiment provides a power switch driving method, which is applied to the power switch driving circuit in the above embodiment. Figure 3 FIG. 1 is a flow chart of a power switch driving method according to an embodiment of the present invention. Figure 3 As shown, the method includes:

[0081] S101, controlling the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch.

[0082] When there is no spike voltage on the gate of the power switch, the voltage between the second resistor and the gate of the power switch is less than the preset threshold, and the first switch is controlled to be turned on; when there is a spike voltage on the gate of the power switch, the voltage between the second resistor and the gate of the power switch is greater than or equal to the preset threshold, and the first switch is controlled to be turned off.

[0083] S102, controlling the value of the driving resistance of the power switch according to the on-off state of the first switch.

[0084] When no spike voltage appears at the gate of the power switch and the first switch is turned on, the second resistor is short-circuited and only the first resistor is connected to the circuit. The value of the driving resistor is equal to the resistance value of the first resistor. At this time, due to the small driving resistance, the switching rate of the power switch is high. When a spike voltage appears at the gate of the power switch and the first switch is turned off, the first resistor and the second resistor are connected to the circuit at the same time. The value of the driving resistor is equal to the sum of the resistance values ​​of the first resistor and the second resistor. At this time, due to the increase in the driving resistance, the switching rate of the power switch is reduced and the spike voltage is suppressed.

[0085] The power switch driving method of this embodiment first controls the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch, and then controls the value of the driving resistor of the power switch according to the on-off state of the first switch. It is possible to change the switching rate of the power switch according to the gate voltage of the power switch, suppress the spike voltage after the spike voltage occurs, and avoid the power switch from being broken down when the spike voltage occurs at the gate, thereby improving reliability and safety.

[0086] Example 4

[0087] This embodiment provides another power switch driving method. In order to control the first switch to be turned on when a peak voltage appears, and to control the first switch to be turned off when no peak voltage appears, the above step S101 specifically includes:

[0088] The breakdown state of the unidirectional element is controlled according to the voltage between the second resistor and the gate of the power switch; wherein the cathode of the unidirectional element is connected between the second resistor and the gate of the power switch, and the cathode is connected to the second voltage divider unit. Specifically, if the voltage between the second resistor and the gate of the power switch is less than a preset threshold, it means that a spike voltage occurs and the unidirectional element breaks down; if the voltage between the second resistor and the gate of the power switch is less than the above preset threshold, it means that no spike voltage occurs and the unidirectional element is cut off.

[0089] The on-off state of the second switch is controlled according to the breakdown state of the unidirectional element; wherein the control end of the second switch is connected to the second voltage dividing unit, the input end is connected to the first voltage dividing unit, and the first voltage dividing unit is connected to the first switch. Specifically, if the unidirectional element breaks down, the second switch is controlled to be turned on; if the unidirectional element is turned off, the second switch is controlled to be turned off.

[0090] The on-off state of the first switch is controlled according to the on-off state of the second switch. Specifically, if the second switch is on, the first switch is controlled to be off; if the second switch is off, the first switch is controlled to be on.

[0091] In order to keep the switching rate of the power switch normal when there is no spike voltage, and reduce the switching rate of the power switch when there is a spike voltage, the value of the driving resistance of the power switch is controlled according to the on-off state of the first switch, including: if the first switch is turned on, the value of the driving resistance of the power switch is controlled to be the resistance value of the first resistor, so that the switching rate of the power switch remains normal; if the first switch is turned off, the value of the driving resistance of the power switch is controlled to be the sum of the resistance value of the first resistor and the resistance value of the second resistor, so that the switching rate of the power switch is reduced; wherein the resistance value of the second resistor is greater than the resistance value of the first resistor.

[0092] To summarize, when no spike voltage appears on the gate of the power switch, the voltage between the second resistor and the gate of the power switch is less than the above-mentioned preset threshold, the unidirectional element is cut off, the second switch is turned off, the first switch is turned on, the value of the driving resistor is the resistance value of the first resistor, and the switching rate remains normal; when a spike voltage appears on the gate of the power switch, the voltage between the second resistor and the gate of the power switch is greater than or equal to the above-mentioned preset threshold, the unidirectional element breaks down, the second switch is turned on, the first switch is turned off, the value of the driving resistor is the sum of the resistance values ​​of the first resistor and the second resistor, the switching rate is reduced, and the spike voltage is suppressed.

[0093] Example 5

[0094] This embodiment provides another power switch driving circuit, which is applied to driving an IGBT. The structure of the power switch driving circuit is as mentioned above. Figure 2 As shown in FIG. 1 , the first output port Vo and the second output port V of the driver chip IC are connected. E The driving signal port of the driving chip is used to output the driving signal. The driving chip IC is also provided with a forward bias source Vcc. The first output port Vo is connected to the gate G of the power switch through the first resistor R1 and the second resistor R2 connected in series. The second output port V E Connect the emitter E of the power switch.

[0095] The resistance value of the first resistor R1 is the recommended value of the driving resistor of the IGBT, and the resistance value of the second resistor R2 is greater than the resistance value of the first resistor R1. The resistance value of the second resistor R2 needs to be determined according to the actual working circuit, but its value cannot be too large, otherwise the switching rate will be too slow, resulting in the phenomenon of simultaneous opening with other IGBTs, and also causing short-circuit breakdown damage to the power switch.

[0096] The power switch driver further includes a unidirectional element Z, a first anti-reverse connection element D1, a second anti-reverse connection element D2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6 for realizing voltage division protection.

[0097] like Figure 2 As shown, the first switch Q1 and the second reverse connection protection element D2 are connected in series and then connected in parallel at both ends of the second resistor R2. The gate (i.e., the control end) of the first switch Q1 is connected to the forward bias source Vcc through the third resistor R3. At the same time, the gate of the first switch Q1 is also connected to the input end of the second switch Q2 through the fourth resistor R4. The gate (i.e., the control end) of the second switch Q2 is connected to the gate G of the IGBT through the fifth resistor R5, the first reverse connection protection element D1 and the unidirectional element Z in sequence. The gate of the second switch Q2 is also connected to the emitter E of the IGBT through the sixth resistor R6. Among them, the second switch Q2 is an NPN transistor, and the first switch Q1 is an N-channel MOS transistor.

[0098] This embodiment provides another power switch driving method, the method comprising:

[0099] S1, detect the gate voltage of the IGBT to determine whether a peak voltage occurs. If not, execute step S2; if yes, execute step S3.

[0100] S2, controls the first switch Q1 to be turned on.

[0101] When no spike voltage occurs, the first output port Vo normally outputs on and off signals, the gate of the IGBT is lower than the preset threshold, the unidirectional element Z is cut off, the second switch Q2 is turned off, and Vcc continues to output a forward bias to the first switch Q1, so that the first switch Q1 is turned on, and the second anti-reverse connection element D2 is also turned on. At this time, the second resistor R2 is short-circuited, and the value of the driving resistor of the IGBT is the resistance value of the first resistor R1. At this time, the IGBT maintains the switching rate during normal operation.

[0102] S3, controlling the first switch Q1 to turn off.

[0103] When a spike voltage appears on the gate, the first output port Vo normally outputs on and off signals, the gate of the IGBT exceeds the preset threshold, the unidirectional element Z is broken down, the first anti-reverse connection element D1 is turned on, the second switch Q2 is turned on, and the front-end potential of the fourth resistor R4 is pulled down, so that the gate voltage of the first switch Q1 is reduced, and then the first switch Q1 is turned off, and the second resistor R2 is connected to the circuit. The value of the driving resistance is the sum of the resistance values ​​of the first resistor R1 and the second resistor R2. At this time, the driving resistance increases, the switching rate of the IGBT is reduced, and the voltage spike is suppressed.

[0104] The power switch driving circuit and method of this embodiment monitors whether there is a spike voltage on the gate of the IGBT when it is running, thereby controlling the resistance value of the driving resistor to change the switching rate of the IGBT. When there is a spike voltage, the switching rate of the IGBT is reduced, the spike voltage is reduced, and the IGBT is protected from breakdown.

[0105] Example 6

[0106] The present embodiment provides an electrical device, including a power switch and the above-mentioned power switch driving circuit, which is used to suppress the peak voltage of the gate of the power switch to ensure stable and reliable operation of the electrical device. In the present embodiment, the above-mentioned electrical device includes at least one of the following: an air conditioner, a washing machine, a refrigerator, a water heater, a fan, a dryer, an air purifier, a water purifier, and a water purifier.

[0107] Example 7

[0108] This embodiment provides a computer-readable storage medium on which a computer program is stored, wherein the program, when executed by a processor, implements the power switch driving method in the above embodiment.

[0109] The circuit embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0110] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power switch driving circuit, characterized in that: The circuit comprises: A first resistor and a second resistor connected in series, wherein the first end of the first resistor is connected to the first output port of the driver chip, and the second end of the second resistor is connected to the gate of the power switch; a first switch, an input end of which is connected between the first resistor and the second resistor, and an output end of which is connected between the second resistor and the gate of the power switch; a control module, whose input end is connected between the second resistor and the gate of the power switch, and whose output end is connected to the control end of the first switch, and is used to control the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch, so as to control the value of the driving resistance of the power switch; The circuit further comprises: The second reverse connection protection element has an anode connected to the output end of the first switch and a cathode connected between the second resistor and the gate of the power switch.

2. The circuit according to claim 1, characterized in that The resistance value of the second resistor is greater than the resistance value of the first resistor.

3. The circuit according to claim 1, characterized in that The control module includes a first voltage dividing unit, a second switch, a second voltage dividing unit and a unidirectional element; Wherein, the first end of the first voltage dividing unit is connected to the forward bias source, the second end is connected to the input end of the second switch, and the third end is connected to the control end of the first switch; The output end of the second switch is connected between the second end of the second voltage dividing unit and the second output port of the driving chip; The first end of the second voltage dividing unit is connected to the anode of the unidirectional element, the second end is connected between the emitter of the power switch and the second output port of the driving chip, and the third end is connected to the control end of the second switch; The cathode of the unidirectional element is connected between the second resistor and the gate of the power switch.

4. The circuit according to claim 3, characterized in that The first voltage dividing unit comprises: A third resistor and a fourth resistor are connected in series at the beginning and the end, the beginning of the third resistor is connected to the forward bias source, the end of the fourth resistor is connected to the input end of the second switch, and the line between the third resistor and the fourth resistor is connected to the control end of the first switch.

5. The circuit according to claim 3, characterized in that The second voltage dividing unit comprises: A fifth resistor and a sixth resistor are connected in series at the beginning and the end, the beginning of the fifth resistor is connected to the anode of the unidirectional element, the end of the sixth resistor is connected between the emitter of the power switch and the second output port of the driver chip, and the line between the fifth resistor and the sixth resistor is connected to the control end of the second switch.

6. The circuit according to claim 3, characterized in that The first switch is an N-channel MOS tube, and the second switch is an NPN transistor.

7. The circuit according to claim 3, characterized in that The control module also includes: A first anti-reverse connection element has an anode connected to the anode of the unidirectional element and a cathode connected to the first end of the second voltage dividing unit.

8. An electrical device, comprising a power switch, characterized in that: It also includes the power switch driving circuit according to any one of claims 1 to 7.

9. The electrical device according to claim 8, characterized in that: The electrical equipment includes at least one of the following: Air conditioners, washing machines, refrigerators, water heaters, fans, dryers, air purifiers, water purifiers, and water purifiers.

10. A power switch driving method, applied to the power switch driving circuit according to any one of claims 1 to 7, characterized in that: The method comprises: Controlling the on / off state of the first switch according to the voltage between the second resistor and the gate of the power switch; The value of the driving resistance of the power switch is controlled according to the on-off state of the first switch.

11. The method according to claim 10, characterized in that Controlling the on-off state of the first switch according to the voltage between the second resistor and the gate of the power switch includes: The breakdown state of the unidirectional element is controlled according to the voltage between the second resistor and the gate of the power switch; wherein the cathode of the unidirectional element is connected between the second resistor and the gate of the power switch, and the cathode is connected to the second voltage dividing unit; The on-off state of the second switch is controlled according to the breakdown state of the unidirectional element; wherein the control end of the second switch is connected to the second voltage dividing unit, the input end is connected to the first voltage dividing unit, and the voltage dividing unit is connected to the first switch; The on / off state of the first switch is controlled according to the on / off state of the second switch.

12. The method according to claim 11, characterized in that Controlling the breakdown state of the unidirectional element according to the voltage between the second resistor and the gate of the power switch comprises: If the voltage between the second resistor and the gate of the power switch is greater than or equal to a preset threshold, the unidirectional element breaks down; If the voltage between the second resistor and the gate of the power switch is less than the preset threshold, the unidirectional element is turned off.

13. The method according to claim 11, characterized in that Controlling the on-off state of the second switch according to the breakdown state of the unidirectional element includes: If the unidirectional element breaks down, controlling the second switch to be turned on; If the unidirectional element is turned off, the second switch is controlled to be turned off.

14. The method according to claim 11, characterized in that Controlling the on-off state of the first switch according to the on-off state of the second switch includes: If the second switch is turned on, controlling the first switch to be turned off; If the second switch is turned off, the first switch is controlled to be turned on.

15. The method according to claim 11, characterized in that Controlling the value of the driving resistance of the power switch according to the on-off state of the first switch includes: If the first switch is turned on, the driving resistance of the power switch is controlled to be the resistance value of the first resistor; If the first switch is turned off, the driving resistance of the power switch is controlled to be the sum of the resistance of the first resistor and the resistance of the second resistor; Wherein, the resistance value of the second resistor is greater than the resistance value of the first resistor.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 10 to 15 is implemented.

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