Gate driving circuit, gate driving chip and electronic equipment

Abstract

The invention discloses a gate drive circuit, a gate drive chip and electronic equipment, and the gate drive circuit comprises an overcurrent protection circuit which is used for sampling a current flowing through a power device to obtain a sampling signal, and controlling the power device to be turned off when the value of the sampling signal is greater than the value of a first reference signal; and the current adjusting circuit is electrically connected with the overcurrent protection circuit and is used for adjusting the gate driving current of the power device based on the sampling signal so as to adjust the switching speed and / or the current output capability of the power device. According to the circuit, the current adjusting circuit is additionally arranged on the basis of an existing overcurrent protection circuit, and the grid driving current of the power device is adjusted based on a sampling signal of the overcurrent protection circuit for the current on the power device, so that the resource utilization rate can be improved; and the switching speed and / or the current output capability of the power device can be adjusted by adjusting the gate driving current of the power device.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and more specifically to a gate drive circuit, a gate drive chip and an electronic device. Background Art

[0002] In the current intelligent power module (IPM) application scheme, an overcurrent protection port is usually set on the driver chip side of the IPM, and a current sampling resistor is placed on the power device such as the insulated gate bipolar transistor (IGBT) end. The current signal flowing through the IGBT is converted into a voltage signal through the sampling resistor, and then the voltage information is sent to the overcurrent protection port of the chip through the RC filter circuit. When the current passing through the IGBT is too large, the voltage on the sampling resistor will also increase. The voltage is sent to the overcurrent protection port of the chip and compared with the reference voltage at the other end of the comparator in the driver chip. If the sampling voltage is greater than the reference voltage, the chip will turn off the drive transistor, and then turn off the IGBT, thereby preventing the IGBT from burning out due to excessive current.

[0003] It can be seen from the existing solutions that the overcurrent protection port is only used to control whether the driver chip shuts off the output by detecting the current information on the IGBT, and has no other control function. Summary of the invention

[0004] According to one aspect of the present application, a gate driving circuit is provided, the gate driving circuit comprising:

[0005] An overcurrent protection circuit, used for sampling the current flowing through the power device to obtain a sampling signal, and when the value of the sampling signal is greater than the value of the first reference signal, controlling the power device to be turned off;

[0006] A current regulating circuit is electrically connected to the overcurrent protection circuit and is used to regulate the gate drive current of the power device based on the sampling signal to adjust the switching speed and / or current output capability of the power device.

[0007] The above technical solution has the following technical effects: a current regulating circuit is added on the basis of the existing overcurrent protection circuit in the driver chip, and the current regulating circuit adjusts the gate drive current of the power device based on the sampling signal of the overcurrent protection circuit on the current on the power device. Therefore, it can not only better utilize existing resources and improve resource utilization, but also adjust the switching speed and / or current output capacity of the power device by adjusting the gate drive current of the power device.

[0008] In an embodiment of the present application, the overcurrent protection circuit includes:

[0009] A first resistor, wherein a first end of the first resistor is connected to the power device, and a second end of the first resistor is grounded;

[0010] a second resistor, wherein a first end of the second resistor is connected to a first end of the first resistor, a second end of the second resistor is connected to a first end of the first capacitor, and a second end of the second resistor outputs the sampling signal;

[0011] The first capacitor, a second end of the first capacitor is grounded;

[0012] a first comparator, wherein a positive input terminal of the first comparator is connected to the second end of the second resistor, a negative input terminal of the first comparator is connected to the first reference signal, and an output terminal of the first comparator is connected to an input terminal of a first inverter;

[0013] The first inverter, an output terminal of the first inverter is connected to a first input terminal of the logic device;

[0014] The logic device, the second input end of the logic device is connected to the input signal of the gate drive circuit, and the signal output by the output end of the logic device is used to control the power device to turn on or off.

[0015] The above technical scheme has the following technical effects: the current flowing through the power device is sampled as a voltage value through the first resistor, and the voltage value is then transmitted to the first comparator through a filtering circuit composed of a second resistor and a first capacitor, and the voltage value is compared with the reference voltage of the first comparator. When the voltage value is greater than the reference voltage, it indicates that the current flowing through the power device is too large. At this time, the first comparator outputs a high-level signal, which is then output as a low-level signal through the first inverter, and passes through a logic device (such as an AND gate) together with the input signal of the gate drive circuit. When the input signal is a high-level signal, the power device should be controlled to be turned on or has been turned on. At this time, the low-level signal output by the first inverter and the high-level signal pass through the AND gate and are output as a low-level signal, thereby controlling the power device to be turned off, thereby achieving overcurrent protection for the power device.

[0016] In an embodiment of the present application, the current regulating circuit includes:

[0017] A signal conversion unit, used for converting the sampled signal from an analog signal into at least two digital signals;

[0018] At least two current regulating units, each of which is connected to one of the digital signals and is used to be turned on or off based on the digital signal, thereby regulating the gate drive current of the power device.

[0019] The above technical solution has the following technical effects: the sampling signal is converted from an analog signal into a multi-channel digital signal through a signal conversion unit, one channel of the digital signal is used to control the on or off of a current regulating unit, and different numbers of current regulating units have different current regulating effects on the gate drive current, thereby conveniently realizing the increase or decrease of the gate drive current.

[0020] In one embodiment of the present application, the signal conversion unit includes:

[0021] An analog-to-digital converter, wherein the analog-to-digital converter comprises an input terminal and a plurality of output terminals, the input terminal of the analog-to-digital converter is connected to the sampling signal, and each output terminal of the analog-to-digital converter outputs one channel of the digital signal.

[0022] The above technical solution has the following technical effects: the analog signal can be converted into a digital signal through the analog-to-digital converter, and the number of bits of the analog-to-digital converter can be selected according to needs to obtain a digital signal of the corresponding number of bits. Each bit of the digital signal is used as a digital signal to control a current regulation unit, thereby realizing the regulation of the gate drive current.

[0023] In another embodiment of the present application, the signal conversion unit includes:

[0024] At least two second comparators, the positive input terminal of each second comparator is connected to the sampling signal, the negative input terminal of each second comparator is connected to a second reference signal, and the output terminal of each second comparator outputs one digital signal.

[0025] The above technical solution has the following technical effects: each comparator can compare the sampled signal with its reference signal and output a digital signal, so multiple comparators can perform this operation separately to output multiple digital signals, and one digital signal is used to control a current regulation unit, thereby realizing the regulation of the gate drive current.

[0026] In one embodiment of the present application, the second reference signal connected to the negative input terminal of each of the second comparators has a different magnitude.

[0027] The above technical solution has the following technical effects: the reference signal input to the negative input terminal of each comparator has different sizes, so that the sampling signal is compared with reference signals of different sizes, which can realize multi-gradient regulation of the current.

[0028] In one embodiment of the present application, the signal conversion unit further includes:

[0029] At least two second inverters, an input end of each second inverter is connected to one of the digital signals, and an output end of each second inverter is connected to one of the current regulating units.

[0030] The above technical solution has the following technical effects: using an inverter can simplify circuit design, reduce the number of logic devices, and reduce circuit complexity. In addition, using an inverter can make the circuit have a faster response speed, lower power consumption and higher reliability, which helps to improve the overall performance of the circuit.

[0031] In one embodiment of the present application, each of the current regulating units includes:

[0032] A multiplexer, the multiplexer comprising a first input terminal, a second input terminal, a third input terminal and an output terminal, the first input terminal is grounded, the second input terminal is connected to the input terminal of the first output stage circuit, the third input terminal is connected to one channel of the digital signal, and the output terminal of the multiplexer is connected to the input terminal of the second output stage circuit;

[0033] The second output stage circuit, the output end of the second output stage circuit and the output end of the first output stage circuit are all connected to the power device.

[0034] The above technical solution has the following technical effects: through the multiplexer, which input is selected as the output according to the different digital signals connected to the multiplexer, thereby controlling the opening or closing of different output stage circuits. The opening or closing of different numbers of output stage circuits can affect the size of the gate drive current, thereby playing a role in regulating the gate drive current.

[0035] In another embodiment of the present application, each of the current regulating units includes:

[0036] The third resistor;

[0037] A switch, wherein the switch is connected in parallel to two ends of the third resistor, and the switch is connected to a path of the digital signal as a control signal of the switch;

[0038] The third resistors of different current regulating units are connected in series to form a resistor string, a first end of the resistor string is connected to an output end of an output stage circuit of the gate driving circuit, and a second end of the resistor string is connected to the power device.

[0039] The above technical solution has the following technical effects: through the digital signal connected to the switch connected in parallel at both ends of the third resistor (that is, the gate drive resistor), the switch can be controlled to be turned on or off, thereby controlling the short circuit or connection of the third resistor, and then controlling the number of third resistors connected to the circuit, thereby affecting the size of the gate drive resistor connected to the circuit, thereby playing a role in regulating the gate drive current.

[0040] In one embodiment of the present application, the current regulating circuit further includes:

[0041] A fourth resistor, wherein a first end of the fourth resistor is connected to the output end of the output stage circuit, and a second end of the fourth resistor is connected to the first end of the resistor string.

[0042] The above technical solution has the following technical effects: adding a gate drive resistor that is not controlled by the digital signal output by the signal conversion unit can achieve additional control of the gate drive current.

[0043] According to another aspect of the present application, a gate driving chip is further provided, and the gate driving chip includes the above-mentioned gate driving circuit.

[0044] According to another aspect of the present application, an electronic device is provided, comprising the above-mentioned gate driving chip.

[0045] According to the gate drive circuit, gate drive chip and electronic device of the embodiments of the present application, a current regulation circuit is added on the basis of the existing overcurrent protection circuit. The current regulation circuit adjusts the gate drive current of the power device based on the sampling signal of the current on the power device by the overcurrent protection circuit. This can not only better utilize existing resources and improve resource utilization, but also adjust the switching speed and / or current output capacity of the power device by adjusting the gate drive current of the power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0047] Figure 1 A schematic structural block diagram of a gate driving circuit according to an embodiment of the present application is shown.

[0048] Figure 2 A schematic circuit diagram of an overcurrent protection circuit in a gate drive circuit according to an embodiment of the present application is shown.

[0049] Figure 3 A schematic structural diagram of a current regulating circuit in a gate driving circuit according to an embodiment of the present application is shown.

[0050] Figure 4 A schematic diagram of a multiplexer in a current regulating unit of a gate driving circuit according to an embodiment of the present application is shown.

[0051] Figure 5 A schematic diagram showing a plurality of output stage circuits connected in parallel in a current regulating unit of a gate driving circuit according to an embodiment of the present application is shown.

[0052] Figure 6 A schematic diagram of a gate driving resistor in a current regulating unit of a gate driving circuit according to an embodiment of the present application is shown.

[0053] Figure 7 A schematic circuit diagram of a gate driving circuit according to an embodiment of the present application is shown.

[0054] Figure 8 A schematic circuit diagram of a gate driving circuit according to another embodiment of the present application is shown.

[0055] Fig. 9 Shows Figure 7 A more complete circuit schematic for the example shown. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0057] Figure 1 FIG. 1 shows a schematic structural block diagram of a gate drive circuit 1 according to an embodiment of the present application. Figure 1 As shown, the gate drive circuit 1 includes an overcurrent protection circuit 11 and a current regulating circuit 12. The overcurrent protection circuit 11 is used to sample the current flowing through the power device to obtain a sampling signal, and when the value of the sampling signal is greater than the value of the first reference signal, the power device is controlled to be turned off. The current regulating circuit 12 is electrically connected to the overcurrent protection circuit, and is used to adjust the gate drive current of the power device based on the sampling signal obtained by sampling the current flowing through the power device by the overcurrent protection circuit 11, so as to adjust the switching speed and / or current output capacity of the power device.

[0058] In an embodiment of the present application, a current regulating circuit 12 is added on the basis of the existing overcurrent protection circuit 11 in the gate drive circuit. The current regulating circuit 12 adjusts the gate drive current of the power device based on the sampling signal of the current on the power device by the overcurrent protection circuit 11. This can not only make better use of existing resources and improve resource utilization, but also adjust the switching speed and / or current output capacity of the power device by adjusting the gate drive current of the power device.

[0059] For example, based on the sampling signal of the current on the power device by the overcurrent protection circuit 11, the current regulating circuit 12 can increase the gate drive current to a certain extent to increase the switching speed of the power device and also increase the current output capacity of the power device. Alternatively, in some scenarios, it may be necessary to reduce the switching speed and / or current output capacity of the power device. In this case, the current regulating circuit 12 can also reduce the gate drive current to a certain extent based on the sampling signal of the current on the power device by the overcurrent protection circuit 11 to reduce the switching speed and / or current output capacity of the power device.

[0060] Based on such adjustment, when the production characteristics of the power device deviate due to factors such as process and packaging, since the characteristics of the power device can be changed by adjusting the gate drive current of the power device, in order to keep the characteristics of the power device consistent during application, the output current (i.e., gate drive current) of the driver chip can be adjusted by the current regulation circuit 12 according to the voltage information obtained by the overcurrent protection circuit 11 to make the characteristics of the power device as consistent as possible, so as to eliminate the characteristic deviation caused by factors such as process and packaging.

[0061] In an embodiment of the present application, the overcurrent protection circuit 11 may further include: a first resistor, wherein the first end of the first resistor is connected to the power device, and the second end of the first resistor is grounded; a second resistor, wherein the first end of the second resistor is connected to the first end of the first resistor, the second end of the second resistor is connected to the first end of the first capacitor, and the second end of the second resistor outputs a sampling signal; a first capacitor, wherein the second end of the first capacitor is grounded; a first comparator, wherein the positive input end of the first comparator is connected to the second end of the second resistor, the negative input end of the first comparator is connected to the first reference signal, and the output end of the first comparator is connected to the input end of the first inverter; a first inverter, wherein the output end of the first inverter is connected to the first input end of the logic device; a logic device, wherein the second input end of the logic device is connected to the input signal of the gate drive circuit, and the signal output by the output end of the logic device is used to control the power device to turn on or off. The following is combined with Figure 2 to describe.

[0062] Figure 2 FIG. 1 shows a schematic circuit diagram of an overcurrent protection circuit 11 in a gate drive circuit according to an embodiment of the present application. Figure 2As shown, the overcurrent protection circuit 12 on the gate drive circuit IC includes a resistor Rshunt, a resistor R1, a capacitor C1, a comparator CMP, an inverter I1, and an AND gate L1. Among them, the first end of the resistor Rshunt is connected to the power device IGBT, and the second end is grounded. The power device is connected to the load and is also connected to other power devices (whose power supply voltage is VP). The resistor R1 and the capacitor C1 constitute a filter circuit, the first end of the resistor R1 is connected to the first end of the resistor Rshunt, the second end of the resistor R1 is connected to the first end of the capacitor C1, and the second end of the resistor R1 outputs the sampling signal VITRIP; the second end of the capacitor C1 is grounded. The positive input end of the comparator CMP is connected to the sampling signal VITRIP, the negative input end is connected to the reference signal VREF, and the output end is connected to the input end of the inverter I1. The output end of the inverter I1 is connected to the first input end of the AND gate L1. The second input end of the AND gate L1 is connected to the input signal IN of the gate drive circuit, and the output end of the AND gate can be connected to the output stage circuit of the gate drive circuit, and the output end OUT of the output stage circuit controls the opening or closing of the power device IGBT. For example, when the voltage value of the sampling signal VITRIP is greater than the voltage value of the reference signal VREF, it indicates that the current flowing through the power device is too large. At this time, the comparator CMP outputs a high-level signal, which is then output as a low-level signal through the inverter I1; the low-level signal and the input signal IN of the gate drive circuit pass through the AND gate L1. When the input signal IN is a high-level signal, the power device IGBT should be controlled to be turned on or has been turned on. At this time, the low-level signal output by the inverter I1 and the high-level signal pass through the AND gate L1 and are output as a low-level signal, thereby controlling the power device IGBT to be turned off, thereby achieving overcurrent protection for the power device IGBT.

[0063] In an embodiment of the present application, the current regulating circuit 12 may further include: a signal conversion unit and at least two current regulating units. The signal conversion unit is used to convert the sampling signal obtained by the overcurrent protection circuit 11 sampling the current flowing through the power device from an analog signal to at least two digital signals; each of the at least two current regulating units is connected to one of the at least two digital signals, and is used to turn on or off based on the digital signal, thereby adjusting the gate drive current of the power device. Figure 3 to describe.

[0064] Figure 3 FIG. 1 shows a schematic structural diagram of a current regulating circuit 12 in a gate driving circuit according to an embodiment of the present application. Figure 3As shown, the current regulating circuit 12 includes a signal conversion unit 121 and four current regulating units 122a, 122b, 122c and 122d (the four current regulating units shown here are exemplary, and other suitable numbers of current regulating units can be set as needed in practice). Among them, the signal conversion unit 121 is used to convert the sampling signal obtained by the overcurrent protection circuit 11 sampling the current flowing through the power device from an analog signal to four digital signals; these four digital signals are respectively used as input signals of the current regulating units 122a, 122b, 122c and 122d, and control the current regulating units 122a, 122b, 122c and 122d to turn on or off, thereby adjusting the gate drive current of the power device. Among the four current regulating units, the number of the current regulating units turned on is different, and the current regulating effect on the gate drive current is different, so that the gate drive current can be easily increased or decreased.

[0065] In one example, the signal conversion unit may include an analog-to-digital converter, which may include an input terminal and multiple output terminals. The input terminal is connected to the overcurrent protection circuit 11 to sample the current flowing through the power device to obtain a sampling signal; each output terminal outputs a digital signal. In this embodiment, the analog signal can be converted into a digital signal through the analog-to-digital converter, and the number of bits of the analog-to-digital converter can be selected according to requirements to obtain a digital signal of a corresponding number of bits. Each bit of the digital signal is used as a digital signal to control a current regulating unit, thereby achieving gate drive current regulation. For example, in Figure 3 In the example shown, the signal conversion unit 121 can be implemented by a four-bit analog-to-digital converter, which outputs the sampling signal obtained by the overcurrent protection circuit 11 sampling the current flowing through the power device as four digital signals for controlling the four current regulating units 122a to 122d.

[0066] In another example, the signal conversion unit may include at least two second comparators (named as such to distinguish them from the first comparator described above), the positive input terminal of each second comparator is connected to the sampling signal obtained by the overcurrent protection circuit 11 sampling the current flowing through the power device, the negative input terminal of each second comparator is connected to a second reference signal, and the output terminal of each second comparator outputs a digital signal. In this embodiment, each comparator can compare the sampling signal with its reference signal and output a digital signal, so multiple comparators can perform this operation separately to output multiple digital signals, and one digital signal is used to control a current regulation unit, thereby realizing the regulation of the gate drive current. For example, in Figure 3In the example shown, the signal conversion unit 121 can be implemented by four comparators, and the sampling signal obtained by the overcurrent protection circuit 11 sampling the current flowing through the power device is output as four digital signals for controlling the four current regulating units 122a to 122d.

[0067] Furthermore, the magnitude of the second reference signal connected to the negative input terminal of each second comparator may be the same, or may be at least partially different. Wherein, when the magnitude of the reference signal input to the negative input terminal of each comparator is different, the sampling signal can be compared with reference signals of different magnitudes, so that multi-gradient regulation of the current can be achieved. This will be described later in conjunction with specific examples.

[0068] In an embodiment of the present application, the signal conversion unit may further include at least two second inverters (named as such to distinguish them from the first inverters described above), the input end of each second inverter being connected to the digital signal described above, and the output end of each second inverter being connected to a current regulating unit. The use of inverters can simplify circuit design, reduce the number of logic devices, and reduce circuit complexity. In addition, the use of inverters can make the circuit have a faster response speed, lower power consumption, and higher reliability, which helps to improve the overall performance of the circuit.

[0069] In one example, each current regulating unit may include a multiplexer and a second output stage circuit. The multiplexer may include a first input terminal, a second input terminal, a third input terminal and an output terminal, the first input terminal is grounded, the second input terminal is connected to the input terminal of the first output stage circuit, the third input terminal is connected to a digital signal, the output terminal of the multiplexer is connected to the input terminal of the second output stage circuit, and the output terminal of the second output stage circuit and the output terminal of the first output stage circuit are both connected to the power device. Figure 4 and Figure 5 to describe.

[0070] Figure 4 FIG. 1 is a schematic diagram showing a multiplexer in a current regulating unit of a gate driving circuit according to an embodiment of the present application. Figure 4As shown, the multiplexer in each current regulating unit includes three input terminals and one output terminal, wherein the sel terminal is connected to a one-bit digital signal output by the aforementioned signal conversion unit. Exemplarily, when the sel terminal is connected to a low-level signal (0), the multiplexer selects input 1 and passes it to the output terminal. Assuming that input 1 is grounded, the output terminal of the multiplexer outputs a low level, and the second output stage circuit connected thereto is turned on, and the power device can be charged. Conversely, when the sel terminal is connected to a high-level signal (1), the multiplexer selects input 2 and passes it to the output terminal. Assuming that input 2 is connected to the input terminal of the first output stage circuit, and the input terminal of the first output stage circuit is connected to the output terminal of the overcurrent protection circuit 11, the output signal of the overcurrent protection circuit can control the opening or closing of the current regulating unit.

[0071] Figure 5 FIG. 1 is a schematic diagram showing a plurality of output stage circuits connected in parallel in a current regulating unit of a gate drive circuit according to an embodiment of the present application. Figure 5 In the figure, n+1 output stage circuits are shown, wherein the 0th stage is the first output stage circuit described above, and the 1st to nth stages are the second output stage circuits described above. The input end of the first output stage circuit is connected to the output end of the overcurrent protection circuit 11, and the input end of the second output stage circuit is connected to the output end of the multiplexer described above. The first output stage circuit and the plurality of second output stage circuits can be regarded as replacing the original output stage circuit (with large-size transistors) of the gate drive circuit with a parallel connection of a plurality of output stage circuits. Alternatively, the first output stage circuit can also be understood as the original output stage circuit, and the plurality of second output stage circuits are circuits included in the newly added current conversion circuit.

[0072] In general, through the multiplexer, which input is selected as the output according to the different digital signals connected to the multiplexer, thereby controlling the opening or closing of different output stage circuits. The opening or closing of different numbers of output stage circuits can affect the size of the gate drive current, thereby playing a role in regulating the gate drive current.

[0073] In another example, each current regulating unit does not include the multiplexer and the second output stage circuit mentioned above, but includes a third resistor and a switch. The switch is connected in parallel at both ends of the third resistor, and the switch is connected to the digital signal mentioned above as the control signal of the switch. The third resistors of different current regulating units are connected in series to form a resistor string, the first end of the resistor string is connected to the output end of the output stage circuit of the gate drive circuit, and the second end of the resistor string is connected to the power device. Figure 6 to describe.

[0074] Figure 6FIG. 1 is a schematic diagram showing a gate drive resistor in a current regulating unit of a gate drive circuit according to an embodiment of the present application. Figure 6 As shown, n current regulating units are shown, each current regulating unit includes a resistor and a switch connected in parallel at both ends of the resistor, these resistors are R1 to Rn, and these switches are SW1 to SWn. Each switch is connected to a one-bit digital signal output by the aforementioned signal conversion unit, which can control the switch to be turned on or off. When switches SW1 to SWn are all disconnected, resistors R1 to Rn are not short-circuited and are all connected to the circuit. At this time, the gate drive resistance is the largest and the gate drive current is the smallest; conversely, when switches SW1 to SWn are all closed, resistors R1 to Rn are all short-circuited and are not connected to the circuit. At this time, the gate drive resistance is the smallest and the gate drive current is the largest. When switches SW1 to SWn are partially disconnected and partially closed, resistors R1 to Rn are partially short-circuited and partially not short-circuited. At this time, the gate drive resistance is between the maximum value and the minimum value, and the gate drive current is between the maximum value and the minimum value. Therefore, the one-bit digital signal output by the aforementioned signal conversion unit connected to each switch can control the disconnection and closing of the switch, thereby controlling the size of the gate drive resistance, and then controlling the size of the gate drive current.

[0075] In general, in this example, the digital signal connected to the switch connected in parallel at both ends of the third resistor (i.e., the gate drive resistor) can control the opening or closing of the switch, thereby controlling the short circuit or connection of the third resistor, and then controlling the number of third resistors connected to the circuit, thereby affecting the size of the gate drive resistor connected to the circuit, thereby playing a role in regulating the gate drive current.

[0076] Furthermore, the current regulating unit may further include a fourth resistor, such as Figure 6 The resistor R0 shown has no parallel switches at both ends and is connected between the output stage circuit and the resistor string, that is, it includes a gate drive resistor that is not controlled by the digital signal output by the signal conversion unit, which can achieve basic control or additional control of the gate drive current.

[0077] The above describes different examples of the signal conversion unit included in the current regulating circuit 12, and different examples of the circuit regulating unit, which can be combined in various ways to form different embodiments of the current regulating circuit, and different examples of the signal conversion unit can be used in combination, and different examples of the circuit regulating unit can also be used in combination. For example, in the first embodiment, the signal conversion unit can be implemented as an analog-to-digital converter, and the circuit regulating unit can be implemented as a multiplexer and a second output stage circuit; in the second embodiment, the signal conversion unit can be implemented as a plurality of comparators, and the circuit regulating unit can be implemented as a multiplexer and a second output stage circuit; in the third embodiment, the signal conversion unit can be implemented as an analog-to-digital converter, and the circuit regulating unit can be implemented as a switch and a third resistor (and can also include a fourth resistor); in the fourth embodiment, the signal conversion unit can be implemented as a plurality of comparators, and the circuit regulating unit can be implemented as a switch and a third resistor (and can also include a fourth resistor); in the fifth embodiment, the above four embodiments can be implemented in various different combinations. For example, the signal conversion unit can be implemented as an analog-to-digital converter, the circuit regulating unit can be implemented as a multiplexer and a second output stage circuit, and the circuit regulating unit also includes the above-mentioned switch and the third resistor (and can also include a fourth resistor), and so on, which are not listed here. Now combine Figure 7 to Figure 8 The first and second embodiments are described above, and other embodiments are not described in detail and can be understood based on the above contents.

[0078] Figure 7 FIG. 2 shows a schematic circuit diagram of a gate drive circuit according to an embodiment of the present application. Figure 7 FIG. 1 shows a partial circuit of the overcurrent protection circuit 11 described above (here, only a partial circuit of the overcurrent protection circuit 11 is shown to highlight the current regulation circuit. The complete circuit of the overcurrent protection circuit, the current regulation circuit, and the circuit including the power device and the load can be found in FIG. Fig. 9 ) and a current regulating circuit, wherein the current regulating circuit includes a signal conversion unit and a plurality of current regulating units. The signal conversion unit includes an n-bit analog-to-digital converter ADC and n inverters, and the current regulating unit includes multiplexers MUX1 to MUXn, and n-stage output stage circuits. The ADC converts the sampling signal VITRIP from an analog quantity to an n-bit digital quantity (DIG(0) to DIG(n-1)), and connects it to n MUX selection circuits through inverters. The outputs of these n MUXs are then connected to the 1st to nth output stage circuits to control whether these output stage circuits are turned on, thereby changing the total output current. For the MUX selection circuit (as described above in combination with Figure 4 As shown in the figure, when the sel terminal is 0, the MUX selects input 1 and passes it to the output terminal. When the sel terminal is 1, the MUX selects input 2 and passes it to the output terminal. For the output stage circuit from level 0 to level n (as shown in the previous text combined with Figure 5 As shown in the figure, the 0th output stage circuit is controlled by the IN signal and the traditional overcurrent protection signal. In the default state, the total output current is determined by the 0th output stage; the 1st to nth output stages are controlled by the output of the MUX circuit. Starting from the 1st output stage, the output current of the 1st stage is set as unit current, and the output current of the next stage is twice the output current of the previous stage. Therefore, the output current of the nth stage is 2^(n-1) times the output current of the 1st stage. The following describes its working process in detail:

[0079] Taking the ADC as a 4-bit ADC as an example, the adjustable current information is adjustable in 16 levels. For example, when the driver IC works in the default state (only the 0th output stage outputs current to the outside), assuming that the current flowing through the IGBT is very small due to insufficient driving capability, and the VITRIP voltage is also very small at this time, then the VITRIP voltage information is converted into a digital code of 0000 after passing through the ADC, and then after passing through the inverter, it becomes a digital code of 1111, then all 4 MUX circuits select input 2 (i.e., IN signal) for output, at this time, the 0th output stage and the following 4 output stage circuits are all turned on, and the total output current reaches the maximum (i.e., the 0th output current plus 15 times the unit current), that is, the gate current driving the IGBT reaches the maximum. If the VITRIP voltage is at the middle level of the ADC range, the ADC outputs a digital code of 1000, and then after passing through the inverter, it is converted into a digital code of 0111, at this time, the 1st, 2nd, and 3rd output stage circuits are turned on, and the 4th output stage circuit is turned off, and the total output current is the 0th output current plus 7 times the unit current. If the VITRIP voltage is very large but does not exceed VREF, the overcurrent protection is not triggered. At this time, VITRIP is converted to a digital code of 1111 through the ADC, and then to a digital code of 0000 through the inverter. Then the 1st to 4th output stages are all turned off, and the total output current is the output current of stage 0. When the VITRIP voltage increases again and reaches the overcurrent protection threshold, the 0th output stage is turned off, the VITRIP voltage is converted to a digital code of 1111 through the ADC, and then to a digital code of 0000 through the inverter. The 1st to 4th output stages are also all turned off, the total output current is 0, and the IGBT is turned off.

[0080] Figure 8 FIG. 2 shows a schematic circuit diagram of a gate drive circuit according to another embodiment of the present application. Figure 8As shown, a partial circuit of the overcurrent protection circuit 11 described above and a current regulation circuit are shown. The current regulation circuit includes a signal conversion unit and multiple current regulation units. The signal conversion unit includes three comparators and three inverters. The current regulation units include multiplexers MUX1 to MUX3 and three-stage output stage circuits. Among them, the reference signal input to the negative input terminal of the comparator CMP in the overcurrent protection current is VREF. The three comparators included in the signal conversion unit are CMP1, CMP2, and CMP3 respectively, and the reference signals input to their respective negative input terminals are VREF1, VREF2, and VREF3 respectively. It is designed that VREF > VREF1 > VREF2 > VREF3. The working process is described in detail below:

[0081] The 0th output stage is default to the open state. When VITRIP is less than VREF3, the outputs of CMP1, CMP2, and CMP3 are all 0, and become 1 after passing through the inverters. MUX1 to MUX3 all select input 2 for output, and the 1st, 2nd, and 3rd output stage circuits are opened, and the total output current is the largest. When VREF2 < VITRIP < VREF1, the output of CMP1 is 0, and the outputs of CMP2 and CMP3 are 1. That is, at this time, the 1st output stage circuit is opened, and the 2nd and 3rd output stage circuits are closed. When VITRIP > VREF (triggering overcurrent protection), the 0th output stage is closed, the outputs of CMP1, CMP2, and CMP3 are all 1, and are all 0 after passing through the inverters. The 1st, 2nd, and 3rd output stage circuits are closed, and the total output current is 0. At this time, the IGBT is turned off.

[0082] In Figure 7 and Figure 8 In the illustrated embodiment, it is a scheme that an ADC or a comparator controls the MUX circuit and then controls the number of parallel output stage circuits to change the output current magnitude. As described above, the output current can also be changed by adjusting the gate drive resistance (as shown in Figure 6 ). At this time, different from Figure 7 and Figure 8 , the reverse output terminals of the ADC and the comparator are not connected to the MUX circuit, but are connected to the switches (SW1, SW2 to SWn) as shown in Figure 6 , and the current is adjusted by changing the number of series gate resistances.

[0083] In addition, as described above, the scheme for adjusting the output stage circuit can be used in combination with the scheme for adjusting the gate drive resistance. Further, the schemes for adjusting the current in the above examples are all methods for increasing the output current under the default output current. In other examples, the scheme that the default state current can be increased or decreased can also be realized by changing the number of output stage circuits or the number of gate drive resistors in the default state. That is, in the above examples, in the default state, SW1 to Swn are all disconnected, R0 to RN are connected in series, the gate drive resistance is the largest, and the gate drive current is the smallest. At this time, the gate drive current can only be increased, not decreased. However, in other examples, for example, SW1 and SW2 are closed in the default state, so that the gate drive current in the default state is not the minimum value, but the intermediate value, and can be increased or decreased in the subsequent adjustment process, rather than only increased. The implementation method of this scheme can be, for example: adding another inverter to the branch where SW1 and SW2 are located (which branches to add inverters depends on how large the user wants the default current to be), and no other structures need to be changed.

[0084] The above describes in detail the gate drive circuit according to the embodiment of the present application. Based on the above description, the gate drive circuit according to the embodiment of the present application adds a current regulating circuit on the basis of the existing overcurrent protection circuit, and the current regulating circuit adjusts the gate drive current of the power device based on the sampling signal of the current on the power device by the overcurrent protection circuit, which can not only make better use of existing resources and improve resource utilization, but also adjust the switching speed and / or current output capacity of the power device by adjusting the gate drive current of the power device.

[0085] According to another aspect of the present application, a gate driving chip is further provided, and the gate driving chip includes the above-mentioned gate driving circuit according to the embodiment of the present application.

[0086] According to another aspect of the present application, an electronic device is provided, which includes the above-mentioned gate driving chip.

[0087] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0088] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0089] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0090] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0091] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0092] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0093] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0094] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functions of some modules in the article analysis device according to the embodiment of the present application. The present application can also be implemented as a device program (e.g., computer program and computer program product) for executing part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0095] It should be noted that the above embodiments illustrate the present application rather than limit the present application, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0096] The above is only a specific implementation method or description of a specific implementation method of the present application, and the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A gate drive circuit, characterized in that: The gate drive circuit comprises: An overcurrent protection circuit, used for sampling the current flowing through the power device to obtain a sampling signal, and when the value of the sampling signal is greater than the value of the first reference signal, controlling the power device to be turned off; A current regulating circuit is electrically connected to the overcurrent protection circuit and is used to regulate the gate drive current of the power device based on the sampling signal to adjust the switching speed and / or current output capability of the power device.

2. The gate driving circuit according to claim 1, characterized in that: The overcurrent protection circuit comprises: A first resistor, wherein a first end of the first resistor is connected to the power device, and a second end of the first resistor is grounded; a second resistor, wherein a first end of the second resistor is connected to a first end of the first resistor, a second end of the second resistor is connected to a first end of the first capacitor, and a second end of the second resistor outputs the sampling signal; The first capacitor, a second end of the first capacitor is grounded; a first comparator, wherein a positive input terminal of the first comparator is connected to the second end of the second resistor, a negative input terminal of the first comparator is connected to the first reference signal, and an output terminal of the first comparator is connected to an input terminal of a first inverter; The first inverter, an output terminal of the first inverter is connected to a first input terminal of the logic device; The logic device, the second input end of the logic device is connected to the input signal of the gate drive circuit, and the signal output by the output end of the logic device is used to control the power device to turn on or off.

3. The gate driving circuit according to claim 1, characterized in that: The current regulating circuit comprises: A signal conversion unit, used for converting the sampled signal from an analog signal into at least two digital signals; At least two current regulating units, each of which is connected to one of the digital signals and is used to be turned on or off based on the digital signal, thereby regulating the gate drive current of the power device.

4. The gate driving circuit according to claim 3, characterized in that: The signal conversion unit comprises: An analog-to-digital converter, wherein the analog-to-digital converter comprises an input terminal and a plurality of output terminals, the input terminal of the analog-to-digital converter is connected to the sampling signal, and each output terminal of the analog-to-digital converter outputs one channel of the digital signal.

5. The gate driving circuit according to claim 3, characterized in that: The signal conversion unit comprises: At least two second comparators, the positive input terminal of each second comparator is connected to the sampling signal, the negative input terminal of each second comparator is connected to a second reference signal, and the output terminal of each second comparator outputs one digital signal.

6. The gate driving circuit according to claim 5, characterized in that: The second reference signal connected to the negative input terminal of each second comparator has a different magnitude.

7. The gate drive circuit according to any one of claims 3 to 6, characterized in that: The signal conversion unit also includes: At least two second inverters, an input end of each second inverter is connected to one of the digital signals, and an output end of each second inverter is connected to one of the current regulating units.

8. The gate drive circuit according to any one of claims 3 to 6, characterized in that: Each of the current regulating units comprises: A multiplexer, the multiplexer comprising a first input terminal, a second input terminal, a third input terminal and an output terminal, the first input terminal is grounded, the second input terminal is connected to the input terminal of the first output stage circuit, the third input terminal is connected to one channel of the digital signal, and the output terminal of the multiplexer is connected to the input terminal of the second output stage circuit; The second output stage circuit, the output end of the second output stage circuit and the output end of the first output stage circuit are all connected to the power device.

9. The gate driving circuit according to any one of claims 3 to 6, characterized in that: Each of the current regulating units comprises: The third resistor; A switch, wherein the switch is connected in parallel to two ends of the third resistor, and the switch is connected to a path of the digital signal as a control signal of the switch; The third resistors of different current regulating units are connected in series to form a resistor string, a first end of the resistor string is connected to an output end of an output stage circuit of the gate driving circuit, and a second end of the resistor string is connected to the power device.

10. The gate driving circuit according to claim 9, characterized in that: The current regulating circuit further includes: A fourth resistor, wherein a first end of the fourth resistor is connected to the output end of the output stage circuit, and a second end of the fourth resistor is connected to the first end of the resistor string.

11. A gate driver chip, characterized in that: The gate driving chip comprises the gate driving circuit according to any one of claims 1-10.

12. An electronic device, characterized in that: The electronic device comprises the gate driving chip according to claim 11.

Images