Current sampling circuit and current sampling method based on gallium nitride power tube

Abstract

The invention discloses a current sampling circuit and a current sampling method based on a gallium nitride power tube, and belongs to the technical field of circuits. A temperature compensation module in the current sampling circuit can ensure that the on-resistance proportions of a silicon sampling tube and an upper tube / a lower tube are kept consistent in different temperature ranges; when the upper tube is conducted, the first temperature compensation module controls the first negative feedback module to generate a positive current or a negative current in proportion to a sampling current, the first current mirror image module outputs the positive current or the negative current to the sampling module, and the sampling module calculates the sampling current of the upper tube according to the positive current or the negative current; when the lower tube is switched on, the second temperature compensation module controls the second negative feedback module to generate a positive current or a negative current in proportion to the sampling current, the second current mirror image module outputs the positive current or the negative current to the sampling module, and the sampling module calculates the sampling current of the lower tube according to the positive current or the negative current. According to the invention, temperature compensation can be carried out, and bidirectional current sampling can be realized.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a current sampling circuit and a current sampling method based on a gallium nitride power tube. Background Art

[0002] Compared with silicon (Si) power tubes, gallium nitride (GaN) power tubes have smaller parasitic capacitance and lower on-resistance and are widely used in high-voltage switching power supplies.

[0003] like Figure 1 As shown, the high voltage switching power supply includes a gallium nitride power tube M T and M B When sampling the current of the high-voltage switching power supply, a silicon sampling tube is usually used to sample the current of the GaN power tube. Since the sampling current is usually one thousandth of the current of the GaN power tube, the loss of the silicon sampling tube can be ignored. However, the on-resistance of the silicon sampling tube does not match the on-resistance of the GaN power tube at different temperatures, resulting in low sampling accuracy over the entire temperature range. Summary of the invention

[0004] The present application provides a current sampling circuit and current sampling method based on a gallium nitride power tube, which is used to solve the problem that the on-resistance of a silicon sampling tube and the on-resistance of a gallium nitride power tube do not match at different temperatures, resulting in low sampling accuracy over the entire temperature range. The technical solution is as follows: According to a first aspect of the present application, a current sampling circuit based on a gallium nitride power tube is provided, the current sampling circuit comprising an upper tube sampling circuit and a lower tube sampling circuit, the upper tube sampling circuit is used to perform current sampling on an upper tube in a high-voltage switching power supply, the lower tube sampling circuit is used to perform current sampling on a lower tube in the high-voltage switching power supply, and the upper tube and the lower tube are gallium nitride power tubes; The upper tube sampling circuit includes a first temperature compensation module, a first negative feedback module, a first current mirror module and a sampling module connected in sequence; the first temperature compensation module includes a first silicon sampling upper tube and a first upper sampling tube resistance compensation array connected, and a first silicon sampling lower tube and a first lower sampling tube resistance compensation array connected, the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array are respectively connected to the upper tube to ensure that the on-resistance ratio of the first silicon sampling upper tube to the upper tube is consistent within different temperature ranges, and the on-resistance ratio of the first silicon sampling lower tube to the upper tube is consistent; When the upper tube is turned on, the first temperature compensation module is used to make the first silicon sampling lower tube and the first lower sampling tube resistance compensation array flow a positive current proportional to the sampling current of the upper tube through the first negative feedback module, or make the first silicon sampling upper tube and the first upper sampling tube resistance compensation array flow a negative current proportional to the sampling current of the upper tube through the first negative feedback module; the first current mirror module is used to output the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module is used to calculate the sampling current of the upper tube according to the positive current or the negative current; The lower tube sampling circuit includes a second temperature compensation module, a second negative feedback module, a second current mirror module and a sampling module connected in sequence; the second temperature compensation module includes a second silicon sampling upper tube and a second upper sampling tube resistance compensation array connected, and a second silicon sampling lower tube and a second lower sampling tube resistance compensation array connected, the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are respectively connected to the lower tube to ensure that the on-resistance ratio of the second silicon sampling upper tube and the lower tube is consistent within different temperature ranges, and the on-resistance ratio of the second silicon sampling lower tube and the lower tube is consistent; When the lower tube is turned on, the second temperature compensation module is used to make the second silicon sampling lower tube and the second lower sampling tube resistance compensation array flow a positive current proportional to the sampling current of the lower tube through the second negative feedback module, or make the second silicon sampling upper tube and the second upper sampling tube resistance compensation array flow a negative current proportional to the sampling current of the lower tube through the second negative feedback module; the second current mirror module is used to output the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module is used to calculate the sampling current of the lower tube according to the positive current or the negative current.

[0005] In a possible implementation, the first temperature compensation module includes a first silicon sampling upper tube, a first silicon sampling lower tube, a first upper sampling tube resistance compensation array, and a first lower sampling tube resistance compensation array; The source of the first silicon sampling upper tube is connected to the first output end of the first negative feedback module as the first input end of the first temperature compensation module; the drain of the first silicon sampling upper tube is connected to the first end of the first upper sampling tube resistance compensation array; the second end of the first upper sampling tube resistance compensation array is connected to the drain of the upper tube as the first output end of the first temperature compensation module; The drain of the first silicon sampling lower tube is connected to the second output end of the first negative feedback module as the second input end of the first temperature compensation module; the source of the first silicon sampling lower tube is connected to the first end of the first lower sampling tube resistance compensation array; the second end of the first lower sampling tube resistance compensation array is connected to the source of the upper tube as the second output end of the first temperature compensation module; The gates of the first silicon sampling upper tube and the first silicon sampling lower tube are respectively connected to the gate of the upper tube.

[0006] In a possible implementation, the first negative feedback module includes a first high-bandwidth operational amplifier, a second high-bandwidth operational amplifier, a first power tube, and a second power tube; The negative input terminal of the first high-bandwidth operational amplifier, the positive input terminal of the second high-bandwidth operational amplifier and the drain of the second power tube are connected to serve as the first output terminal of the first negative feedback module; The positive input terminal of the first high-bandwidth operational amplifier, the negative input terminal of the second high-bandwidth operational amplifier and the drain of the first power tube are connected to serve as the second output terminal of the first negative feedback module; The output end of the first high-bandwidth operational amplifier is connected to the gate of the first power tube and then serves as the third output end of the first negative feedback module, and is connected to the first input end of the first current mirror module; The output end of the second high-bandwidth operational amplifier is connected to the gate of the second power tube and then serves as the fourth output end of the first negative feedback module, and is connected to the second input end of the first current mirror module; The sources of the first power tube and the second power tube are respectively connected to the bootstrap voltage as input terminals of the first negative feedback module.

[0007] In a possible implementation, the first current mirror module includes a third power tube, a fourth power tube, a first high-voltage tube, a first low-voltage tube, a second high-voltage tube, and a second low-voltage tube; The gate of the third power tube serves as the first input end of the first current mirror module; the gate of the fourth power tube serves as the second input end of the first current mirror module; The source of the third power tube is connected to the bootstrap voltage as the third input terminal of the first current mirror module; the source of the fourth power tube is connected to the bootstrap voltage as the fourth input terminal of the first current mirror module; The drain of the third power tube is connected to the source of the first high-voltage tube; the drain of the first high-voltage tube is respectively connected to the drain and gate of the first low-voltage tube and serves as the first output end of the first current mirror module, and is connected to the first input end of the sampling module; the source of the first low-voltage tube is grounded; the gate of the first high-voltage tube is connected to the source of the upper tube; The drain of the fourth power tube is connected to the source of the second high-voltage tube; the drain of the second high-voltage tube is respectively connected to the drain and gate of the second low-voltage tube and serves as the second output end of the first current mirror module, and is connected to the second input end of the sampling module; the source of the second low-voltage tube is grounded; and the gate of the second high-voltage tube is connected to the source of the upper tube.

[0008] In a possible implementation, the second temperature compensation module includes a second silicon sampling upper tube, a second silicon sampling lower tube, a second lower sampling tube resistance compensation array, and a second lower sampling tube resistance compensation array; The source of the second silicon sampling upper tube is connected to the first output end of the second negative feedback module as the first input end of the second temperature compensation module; the drain of the second silicon sampling upper tube is connected to the first end of the second lower sampling tube resistance compensation array; the second end of the second lower sampling tube resistance compensation array is connected to the drain of the lower tube as the first output end of the second temperature compensation module; The drain of the second silicon sampling lower tube is connected to the second output end of the second negative feedback module as the second input end of the second temperature compensation module; the source of the second silicon sampling lower tube is connected to the first end of the second lower sampling tube resistance compensation array; the second end of the second lower sampling tube resistance compensation array is connected to the source of the lower tube as the second output end of the second temperature compensation module; The gates of the second silicon sampling upper tube and the second silicon sampling lower tube are respectively connected to the gate of the lower tube.

[0009] In a possible implementation, the second negative feedback module includes a third high-bandwidth operational amplifier, a fourth high-bandwidth operational amplifier, a fifth power tube, and a sixth power tube; The negative input terminal of the third high-bandwidth operational amplifier, the positive input terminal of the fourth high-bandwidth operational amplifier and the drain of the sixth power tube are connected to serve as the first output terminal of the second negative feedback module; The positive input terminal of the third high-bandwidth operational amplifier, the negative input terminal of the fourth high-bandwidth operational amplifier and the drain of the fifth power tube are connected to serve as the second output terminal of the second negative feedback module; The output end of the third high-bandwidth operational amplifier is connected to the gate of the fifth power tube and then serves as the third output end of the second negative feedback module, and is connected to the first input end of the second current mirror module; The output end of the fourth high-bandwidth operational amplifier is connected to the gate of the sixth power tube and then serves as the fourth output end of the second negative feedback module, and is connected to the second input end of the second current mirror module; The sources of the fifth power tube and the sixth power tube are respectively connected to the bootstrap voltage as input terminals of the second negative feedback module.

[0010] In a possible implementation, the second current mirror module includes a seventh power tube, an eighth power tube, a third high-voltage tube, a third low-voltage tube, a fourth high-voltage tube and a fourth low-voltage tube; The gate of the seventh power tube serves as the first input end of the second current mirror module; the gate of the eighth power tube serves as the second input end of the second current mirror module; The source of the seventh power tube is connected to the bootstrap voltage as the third input terminal of the second current mirror module; the source of the eighth power tube is connected to the bootstrap voltage as the fourth input terminal of the second current mirror module; The drain of the seventh power tube is connected to the source of the third high-voltage tube; the drain of the third high-voltage tube is respectively connected to the drain and gate of the third low-voltage tube and serves as the first output end of the second current mirror module, and is connected to the first input end of the sampling module; the source of the third low-voltage tube is grounded; the gate of the third high-voltage tube is connected to the drain of the lower tube; The drain of the eighth power tube is connected to the source of the fourth high-voltage tube; the drain of the fourth high-voltage tube is respectively connected to the drain and gate of the fourth low-voltage tube and serves as the second output end of the second current mirror module, and is connected to the second input end of the sampling module; the source of the fourth low-voltage tube is grounded; and the gate of the fourth high-voltage tube is connected to the drain of the lower tube.

[0011] In a possible implementation, the sampling module includes a sample-and-hold circuit, a first current source, a second current source, a sampling resistor, and a reference power supply; The first end of the sample-and-hold circuit serves as the first input end of the sampling module; the second end of the sample-and-hold circuit serves as the second input end of the sampling module; the third end of the sample-and-hold circuit is connected to the first end of the first current source; the fourth end of the sample-and-hold circuit is connected to the first end of the second current source; The second end of the first current source is connected to the internal power supply voltage; the third end of the first current source is respectively connected to the second end of the second current source and the first end of the sampling resistor; the third end of the second current source is grounded; The second end of the sampling resistor is connected to the positive electrode of the reference voltage; the negative electrode of the reference voltage is grounded.

[0012] In a possible implementation, when the sampling module includes a reference voltage, the voltage on the sampling resistor is equal to the reference voltage plus the sampling voltage, and the sampling voltage is equal to the product of the sampling current, the proportionality coefficient and the sampling resistor.

[0013] According to a second aspect of the present application, a current sampling method of a current sampling circuit based on a gallium nitride power tube is provided, which is used in the current sampling circuit based on a gallium nitride power tube as described above, and the method includes: When the upper tube is turned on, the first negative feedback module causes the first silicon sampling lower tube and the first lower sampling tube resistance compensation array to flow a positive current proportional to the sampling current of the upper tube, or the first negative feedback module causes the first silicon sampling upper tube and the first upper sampling tube resistance compensation array to flow a negative current proportional to the sampling current of the upper tube; the first current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the upper tube according to the positive current or the negative current; When the lower tube is turned on, a forward current proportional to the sampling current of the lower tube flows through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, or a negative current proportional to the sampling current of the lower tube flows through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module; the second current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the lower tube according to the positive current or the negative current.

[0014] The beneficial effects of the technical solution provided by this application include at least: When a silicon sampling tube is used to sample the current of a gallium nitride power tube, temperature compensation is required through a resistor compensation array to ensure that the on-resistance ratio of the silicon sampling tube and the gallium nitride power tube remains consistent within different temperature ranges, thereby improving the accuracy of current sampling.

[0015] When current sampling is performed on the upper tube, a first negative feedback module can be used to allow a forward current proportional to the sampling current of the upper tube to flow through the first silicon sampling lower tube and the first lower sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the positive current; or, a first negative feedback module can be used to allow a negative current proportional to the sampling current of the upper tube to flow through the first silicon sampling upper tube and the first upper sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the negative current, thereby achieving bidirectional current sampling of the upper tube.

[0016] When current sampling is performed on the lower tube, a forward current proportional to the sampling current of the lower tube can be passed through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the positive current; or, a negative current proportional to the sampling current of the lower tube can be passed through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the negative current, thereby realizing bidirectional current sampling of the lower tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 It is a structural schematic diagram of a current sampling circuit based on a gallium nitride power tube according to the related art; Figure 2 It is a structural schematic diagram of a current sampling circuit based on a gallium nitride power tube provided by an embodiment of the present application; Figure 3 is a schematic diagram of the structure of a resistance compensation array provided by an embodiment of the present application; Figure 4 is a structural schematic diagram of an upper tube sampling circuit provided by an embodiment of the present application; Figure 5 is a structural schematic diagram of an upper tube sampling circuit provided by an embodiment of the present application; Figure 6 is a structural schematic diagram of a down-pipe sampling circuit provided by an embodiment of the present application; Figure 7 is a structural schematic diagram of a down-pipe sampling circuit provided by an embodiment of the present application; Figure 8 It is a structural schematic diagram of an upper and lower tube sampling circuit provided by an embodiment of the present application; Fig. 9 This is a flow chart of a current sampling method based on a gallium nitride power tube provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0020] like Figure 2As shown, an embodiment of the present application provides a current sampling circuit based on a gallium nitride power tube, the current sampling circuit includes an upper tube sampling circuit 210 and a lower tube sampling circuit 220, the upper tube sampling circuit 210 is used to sample the upper tube M in the high-voltage switching power supply T For current sampling, the lower tube adopts circuit 220 for sampling the lower tube M in the high voltage switching power supply. B Perform current sampling.

[0021] In this embodiment, the upper tube M T and down tube M B The sampling circuit uses a silicon sampling tube for the GaN power tube. However, the on-resistance of the silicon sampling tube does not match the on-resistance of the GaN power tube at different temperatures. Therefore, temperature compensation is required to ensure that the on-resistance ratio of the silicon sampling tube to the upper tube and the lower tube remains consistent within different temperature ranges.

[0022] Specifically, a resistor compensation array can be used to match the on-resistance of the silicon sampling tube and the gallium nitride power tube. The resistor compensation array is composed of a resistor with a positive temperature coefficient and a resistor with a negative temperature coefficient connected in series, such as Figure 3 As shown, R PT1 , R PT2 , R PT3 , R PT4 and R PT5 Represents a resistor with a positive temperature coefficient, R NT1 , R NT2 , R NT3 , R NT4 and R NT5 Indicates a resistor with a negative temperature coefficient. Of course, in actual use, the number of resistors can be set according to actual needs, and there is no limitation here.

[0023] When the resistance compensation matrix is ​​used for the first time, the resistance compensation matrix needs to be calibrated. Specifically, when the slope of the temperature curve of the on-resistance of the silicon sampling tube is greater than the slope of the temperature curve of the on-resistance of the gallium nitride power tube, we will blow the fuse with the negative temperature coefficient resistor to connect the resistor to the sampling circuit. Similarly, when the slope of the temperature curve of the on-resistance of the silicon sampling tube is less than the slope of the temperature curve of the on-resistance of the gallium nitride power tube, we will blow the fuse with the positive temperature coefficient resistor to connect the resistor to the sampling circuit. After calibration, the resistors connected to the sampling circuit in the resistance compensation matrix are fixed, and there is no need to adjust the resistance compensation matrix when using the sampling circuit subsequently.

[0024] like Figure 4 and Figure 5As shown, in the calibrated sampling circuit, the upper tube sampling circuit 210 includes a first temperature compensation module 211, a first negative feedback module 212, a first current mirror module 213 and a sampling module 214 connected in sequence; the first temperature compensation module 211 includes a first silicon sampling upper tube M connected SH1 and the first upper sampling tube resistance compensation array, and the first silicon sampling lower tube M connected thereto. SH2 and a first down sampling tube resistance compensation array, the first up sampling tube resistance compensation array and the first down sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the first up sampling tube resistance compensation array and the first down sampling tube resistance compensation array are respectively connected to the upper tube M T connected to ensure that in different temperature ranges, the first silicon sampling tube M SH1 With top tube M T The on-resistance ratio of the first silicon sampling tube M SH2 With top tube M T The on-resistance ratio remains consistent.

[0025] Top tube M T When the current flows from V IN Flow to V SW (Current I MT direction is positive), the first temperature compensation module 211 is used to control V in the first negative feedback module 212 A =V B , so that the first silicon sample down tube M SH2 The first lower sampling tube resistance compensation array flows through the upper tube M T The sampling current I MT Proportional forward current I SHP , or, when the current flows from V SW Flow to V IN (Current I MT direction is negative), by controlling V A =V B , so that the first silicon sampling tube M SH1 and the first upper sampling tube resistance compensation array flows through the upper tube M T The sampling current I MT Proportional negative current I SHN The first current mirror module 213 is used to convert the forward current I SHP Or negative current I SHN The image output is sent to the sampling resistor R in the sampling module 214. SNS ; The sampling module 214 is used to calculate the forward current I SHP Or negative current I SHN Calculate the upper tube M T The sampling current I MT.

[0026] like Figure 6 and Figure 7 As shown, in the calibrated sampling circuit, the lower tube sampling circuit 220 includes a second temperature compensation module 221, a second negative feedback module 222, a second current mirror module 223 and a sampling module 214 connected in sequence; the second temperature compensation module 221 includes a second silicon sampling upper tube M connected SH3 and the second upper sampling tube resistance compensation array, and the connected second silicon sampling lower tube M SH4 and the second lower sampling tube resistance compensation array, the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are respectively connected to the lower tube M B connected to ensure that the second silicon sampling tube M SH3 With down tube M B The on-resistance ratio of the second silicon sampling tube M SH4 With down tube M B The on-resistance ratio remains consistent.

[0027] Down tube M B When the current flows from V SW Flowing to ground (current I MB direction is positive), the second temperature compensation module 221 is used to control V in the second negative feedback module 222 A =V B , so that the second silicon sampling tube M SH4 The second lower sampling tube resistance compensation array flows through the lower tube M B The sampling current I MB Proportional forward current I SHP , or, when current flows from ground to V SW (Current I MB direction is negative), by controlling V A =V B , so that the second silicon sampling tube M SH3 The second upper sampling tube resistor compensation array flows through the lower tube M B The sampling current I MB Proportional negative current I SHN The second current mirror module 223 is used to convert the forward current I SHP Or negative current I SHN The image output is sent to the sampling resistor R in the sampling module 214. SNS ; The sampling module 214 is used to calculate the forward current I SHP Or negative current I SHN Calculate the lower tube MB The sampling current I MB .

[0028] Figure 8 The complete current sampling circuit including the upper tube sampling circuit 210 and the lower tube sampling circuit 220 is shown.

[0029] The structures of the upper tube sampling circuit 210 and the lower tube sampling circuit 220 are described below respectively.

[0030] (I) Upper tube sampling circuit 210 (1) First temperature compensation module 211 The first temperature compensation module 211 includes a first silicon sampling upper tube M SH1 , the first silicon sampling tube M SH2 , a first upper sampling tube resistance compensation array and a first lower sampling tube resistance compensation array; The first silicon sampling tube M SH1 The source of the first temperature compensation module 211 is connected to the first output end of the first negative feedback module 212 as the first input end of the first temperature compensation module 211; SH1 The drain of the first sampling tube resistance compensation array is connected to the first end; the second end of the first sampling tube resistance compensation array is connected to the first output end of the first temperature compensation module 211 and the upper tube M T The drain of is connected; The first silicon sampling tube M SH2 The drain of the first temperature compensation module 211 is connected to the second output end of the first negative feedback module 212 as the second input end of the first temperature compensation module 211; SH2 The source of the first down sampling tube resistance compensation array is connected to the first end; the second end of the first down sampling tube resistance compensation array is connected to the upper tube M as the second output end of the first temperature compensation module 211. T The source of is connected; The first silicon sampling tube M SH1 and the first silicon sample tube M SH2 The gate of the upper tube M T The gate TG is connected to.

[0031] (2) First negative feedback module 212 The first negative feedback module 212 includes a first high bandwidth operational amplifier Positive HB AMP1, a second high bandwidth operational amplifier Negative HB AMP1, a first power tube M SM1 And the second power tube M SM3 ; The negative input terminal of the first high bandwidth operational amplifier Positive HB AMP1, the positive input terminal of the second high bandwidth operational amplifier Negative HBAMP1 and the second power tube MSM3 The drain of is connected to serve as the first output end of the first negative feedback module 212; The positive input terminal of the first high bandwidth operational amplifier Positive HB AMP1, the negative input terminal of the second high bandwidth operational amplifier Negative HBAMP1 and the first power tube M SM1 The drain of is connected to serve as the second output end of the first negative feedback module 212; The output end of the first high bandwidth operational amplifier Positive HB AMP1 is connected to the first power tube M SM1 After being connected to the gate of the first current mirror module 213, it serves as the third output terminal of the first negative feedback module 212 and is connected to the first input terminal of the first current mirror module 213; The output end of the second high bandwidth operational amplifier Negative HB AMP1 is connected to the second power tube M SM3 After being connected to the gate of the first current mirror module 213, it serves as the fourth output terminal of the first negative feedback module 212 and is connected to the second input terminal of the first current mirror module 213; The first power tube M SM1 And the second power tube M SM3 The source of the first negative feedback module 212 is connected to the bootstrap voltage V BST connected.

[0032] (3) First current mirror module 213 The first current mirror module 213 includes a third power tube M SM2 , the fourth power tube M SM4 , the first high pressure pipe M HV1 , the first low pressure pipe M LV1 , the second high pressure pipe M HV2 and the second low-pressure pipe M LV2 ; The third power tube M SM2 The gate of the fourth power tube M is used as the first input terminal of the first current mirror module 213; SM4 The gate of the first current mirror module 213 is used as the second input terminal; The third power tube M SM2 The source of the first current mirror module 213 is connected to the bootstrap voltage V BST Connected; the fourth power tube M SM4 The source of the first current mirror module 213 is connected to the bootstrap voltage V BST connected; The third power tube M SM2 The drain electrode and the first high voltage tube M HV1 The source of the first high-voltage tube M HV1 The drain of the first low-voltage tube M LV1The drain and gate of the first low-voltage transistor M are connected as the first output end of the first current mirror module 213, and are connected to the first input end of the sampling module 214; LV1 The source of the first high voltage tube M is grounded; HV1 The gate and upper tube M T The source of is connected; The fourth power tube M SM4 The drain electrode and the second high voltage tube M HV2 The source of the second high-voltage tube M HV2 The drain of the second low-voltage tube M LV2 The drain and gate of the second low-voltage transistor M are connected as the second output end of the first current mirror module 213, and are connected to the second input end of the sampling module 214; LV2 The source of the second high voltage tube M HV2 The gate and upper tube M T The source is connected.

[0033] (4) Sampling module 214 The sampling module 214 includes a sampling and holding circuit, a first current source I1, a second current source I2, a sampling resistor R SNS and reference power supply V REF ; The first end of the sampling and holding circuit is used as the first input end of the sampling module 214; the second end of the sampling and holding circuit is used as the second input end of the sampling module 214; the third end of the sampling and holding circuit is connected to the first end of the first current source I1; the fourth end of the sampling and holding circuit is connected to the first end of the second current source I2; The second terminal of the first current source I1 is connected to the internal power supply voltage V CC The third end of the first current source I1 is connected to the second end of the second current source I2 and the sampling resistor R SNS The first end of the second current source I2 is connected to the ground; the third end of the second current source I2 is grounded; Sampling resistor R SNS The second end is connected to the reference voltage V REF The positive pole is connected to the reference voltage V REF The negative pole of the

[0034] When the current flows from V IN Flow to V SW (Current I MT direction is positive), the first silicon sampling upper tube M in the first temperature compensation module 211 SH1 , the first silicon sampling tube M SH2 , the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array, the first high bandwidth operational amplifier Positive HB AMP1 and the first power tube M in the first negative feedback module 212 SM1, the third power tube M in the first current mirror module 213 SM2 , the first high pressure pipe M HV1 and the first low pressure pipe M LV1 , the sampling and holding circuit in the sampling module 214, the first current source I1, the sampling resistor R SNS and reference power supply V REF Connect to the upper tube sampling circuit 210, that is, Figure 4 The black components in FIG. 1 are connected to the upper tube sampling circuit 210 , and the gray components are not connected to the upper tube sampling circuit 210 .

[0035] When the current flows from V SW Flow to V IN (Current I MT direction is negative), the first silicon sampling upper tube M in the first temperature compensation module 211 SH1 , the first silicon sampling tube M SH2 , the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array, the second high bandwidth operational amplifier Negative HB AMP1 in the first negative feedback module 212 and the second power tube M SM3 , the fourth power tube M in the first current mirror module 213 SM4 , the second high pressure pipe M HV2 and the second low-pressure pipe M LV2 , the sampling and holding circuit in the sampling module 214, the second current source I2, the sampling resistor R SNS and reference power supply V REF Connect to the upper tube sampling circuit 210, that is, Figure 5 The black components in FIG. 1 are connected to the upper tube sampling circuit 210 , and the gray components are not connected to the upper tube sampling circuit 210 .

[0036] When the sampling module 214 includes a reference voltage V REF When the sampling resistor R SNS The voltage V ISNS Equal to the reference voltage V REF Add sampling voltage, sampling voltage is equal to sampling current I L , proportionality coefficient K m And the sampling resistor R SNS That is, V ISNS =V REF +I L ×K m ×R SNS , where V REF Represents the bias voltage, I L Indicates upper tube M T The sampling current, K m Represents the internal conversion factor, R SNS Indicates the resistance of the sampling resistor.

[0037] (II) Lower tube sampling circuit 220 (1) Second temperature compensation module 221 The second temperature compensation module 221 includes a second silicon sampling upper tube M SH3 , the second silicon sampling tube M SH4 , a second down sampling tube resistance compensation array and a second down sampling tube resistance compensation array; The second silicon sampling upper tube M SH3 The source of the second temperature compensation module 221 is connected to the first output end of the second negative feedback module 222 as the first input end of the second temperature compensation module 221; the second silicon sampling upper tube M SH3 The drain of the second sampling tube is connected to the first end of the second down sampling tube resistance compensation array; the second end of the second down sampling tube resistance compensation array is connected to the down tube M as the first output end of the second temperature compensation module 221 B The drain of is connected; The second silicon sampling tube M SH4 The drain of the second temperature compensation module 221 is connected to the second output end of the second negative feedback module 222 as the second input end of the second temperature compensation module 221; SH4 The source of the second sampling tube is connected to the first end of the second down sampling tube resistance compensation array; the second end of the second down sampling tube resistance compensation array is connected to the second output end of the second temperature compensation module 221 and the down tube M B The source of is connected; The second silicon sampling upper tube M SH3 and the second silicon sampling tube M SH4 The gate of the lower tube M B The gate is connected.

[0038] (2) Second negative feedback module 222 The second negative feedback module 222 includes a third high bandwidth operational amplifier Positive HB AMP2, a fourth high bandwidth operational amplifier Negative HB AMP2, a fifth power tube M SM5 And the sixth power tube M SM7 ; The negative input terminal of the third highest bandwidth operational amplifier Positive HB AMP2, the positive input terminal of the fourth highest bandwidth operational amplifier Negative HBAMP2 and the sixth power tube M SM7 The drain of is connected to serve as the first output end of the second negative feedback module 222; The positive input terminal of the third highest bandwidth operational amplifier Positive HB AMP2, the negative input terminal of the fourth highest bandwidth operational amplifier Negative HBAMP2 and the fifth power tube M SM5 The drain of is connected to serve as the second output end of the second negative feedback module 222; The output of the third high bandwidth operational amplifier Positive HB AMP2 is connected to the fifth power tube M SM5 After being connected to the gate of the second current mirror module 223, it serves as the third output terminal of the second negative feedback module 222 and is connected to the first input terminal of the second current mirror module 223; The output end of the fourth high bandwidth operational amplifier Negative HB AMP2 and the sixth power tube M SM7 After being connected to the gate of the second current mirror module 223, it serves as the fourth output terminal of the second negative feedback module 222 and is connected to the second input terminal of the second current mirror module 223; The fifth power tube M SM5 And the sixth power tube M SM7 The source of the second negative feedback module 222 is connected to the bootstrap voltage V BST connected.

[0039] (3) Second current mirror module 223 The second current mirror module 223 includes a seventh power tube M SM6 、The eighth power tube M SM8 、The third high pressure pipe M HV3 、The third low pressure pipe M LV3 , the fourth high pressure pipe M HV4 And the fourth low pressure pipe M LV4 ; The seventh power tube M SM6 The gate of the eighth power tube M is used as the first input terminal of the second current mirror module 223; SM8 The gate of the second current mirror module 223 is used as the second input terminal; The seventh power tube M SM6 The source of the second current mirror module 223 is connected to the bootstrap voltage V BST Connected; the eighth power tube M SM8 The source of the second current mirror module 223 is connected to the bootstrap voltage V BST connected; The seventh power tube M SM6 The drain electrode and the third high voltage tube M HV3 The source of the third high-voltage tube M HV3 The drain of the third low-voltage tube M LV3 The drain and gate of the third low-voltage transistor M are connected as the first output end of the second current mirror module 223 and connected to the first input end of the sampling module 214; LV3 The source of the third high voltage tube M is grounded; HV3 The gate and the lower tube M B The drain of is connected; The eighth power tube M SM8 The drain electrode and the fourth high voltage tube M HV4The source of the fourth high-voltage tube M HV4 The drain of the fourth low-voltage tube M LV4 The drain and gate of the fourth low-voltage transistor M are connected as the second output end of the second current mirror module 223 and connected to the second input end of the sampling module 214; LV4 The source of the fourth high-voltage tube M is grounded; HV4 The gate and the lower tube M B The drain is connected.

[0040] (4) Sampling module 214 The sampling module 214 is described in detail above and will not be repeated here.

[0041] When the current flows from V SW Flowing to ground (current I MB direction is positive), the second silicon sampling upper tube M in the second temperature compensation module 221 SH3 , the second silicon sampling tube M SH4 , the second down sampling tube resistance compensation array and the second down sampling tube resistance compensation array, the third high bandwidth operational amplifier Positive HB AMP2 in the second negative feedback module 222 and the fifth power tube M SM5 , the seventh power tube M in the second current mirror module 223 SM6 、The third high pressure pipe M HV3 And the third low pressure pipe M LV3 , the sampling and holding circuit in the sampling module 214, the first current source I1, the sampling resistor R SNS and reference power supply V REF Connect to the lower tube sampling circuit 220, that is, Figure 6 The black components in FIG. 1 are connected to the lower tube sampling circuit 220 , and the gray components are not connected to the lower tube sampling circuit 220 .

[0042] When current flows from ground to V SW (Current I MB direction is negative), the second silicon sampling upper tube M in the second temperature compensation module 221 SH3 , the second silicon sampling tube M SH4 , the second down sampling tube resistance compensation array and the second down sampling tube resistance compensation array, the fourth high bandwidth operational amplifier Negative HB AMP2 in the second negative feedback module 222 and the sixth power tube M SM7 , the eighth power tube M in the second current mirror module 223 SM8 , the fourth high pressure pipe M HV4 and the fourth low pressure pipe M LV4 , the sampling and holding circuit in the sampling module 214, the second current source I2, the sampling resistor R SNS and reference power supply V REF Connect to the lower tube sampling circuit 220, that is, Figure 7 The black components in FIG. 1 are connected to the lower tube sampling circuit 220 , and the gray components are not connected to the lower tube sampling circuit 220 .

[0043] When the sampling module 214 includes a reference voltage V REF When the sampling resistor R SNS The voltage V ISNS Equal to the reference voltage V REF Add sampling voltage, sampling voltage is equal to sampling current I L , proportionality coefficient K m And the sampling resistor R SNS That is, V ISNS =V REF +I L ×K m ×R SNS , where V REF Represents the bias voltage, I L Indicates upper tube M T The sampling current, K m Represents the internal conversion factor, R SNS Indicates the resistance of the sampling resistor.

[0044] In summary, the current sampling circuit based on the gallium nitride power tube provided in the embodiment of the present application needs to perform temperature compensation through a resistance compensation array when a silicon sampling tube is used to sample the current of the gallium nitride power tube, so as to ensure that the on-resistance ratio of the silicon sampling tube and the gallium nitride power tube remains consistent within different temperature ranges, thereby improving the accuracy of current sampling.

[0045] When current sampling is performed on the upper tube, a first negative feedback module can be used to allow a forward current proportional to the sampling current of the upper tube to flow through the first silicon sampling lower tube and the first lower sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the positive current; or, a first negative feedback module can be used to allow a negative current proportional to the sampling current of the upper tube to flow through the first silicon sampling upper tube and the first upper sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the negative current, thereby achieving bidirectional current sampling of the upper tube.

[0046] When current sampling is performed on the lower tube, a forward current proportional to the sampling current of the lower tube can be passed through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the positive current; or, a negative current proportional to the sampling current of the lower tube can be passed through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the negative current, thereby realizing bidirectional current sampling of the lower tube.

[0047] like Fig. 9As shown, this embodiment provides a current sampling method applied to the current sampling circuit based on gallium nitride power tube, and the current sampling method includes:

[0048] Step 901, when the upper tube is turned on, a positive current proportional to the sampling current of the upper tube flows through the first silicon sampling lower tube and the first lower sampling tube resistance compensation array through the first negative feedback module, or a negative current proportional to the sampling current of the upper tube flows through the first silicon sampling upper tube and the first upper sampling tube resistance compensation array through the first negative feedback module; the first current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the upper tube according to the positive current or the negative current.

[0049] When the current flows from V IN Flow to V SW (Current I MT direction is positive), V A =V B , causing the forward current I SHP With top tube M T Current I MT Then, the forward current I SHP The first current mirror module sends the current to the sampling module, and the sampling resistor R SNS The voltage V REF Provides bias, generating a voltage V at the output node ISNS .

[0050] When the current flows from V SW Flow to V IN (Current I MT direction is negative), V A =V B , causing the negative current I SHN With top tube M T Current I MT Then, the negative current I SHN The first current mirror module sends the current to the sampling module, and the sampling resistor R SNS The voltage V REF Provides bias, generating a voltage V at the output node ISNS .

[0051] V ISNS =V REF +I L ×K m ×R SNS , where V REF Represents the bias voltage, I L Indicates upper tube M T The sampling current, Km Represents the internal conversion factor, R SNS Indicates the resistance of the sampling resistor.

[0052] Step 902: when the lower tube is turned on, a positive current proportional to the sampling current of the lower tube flows through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, or a negative current proportional to the sampling current of the lower tube flows through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module; the second current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the lower tube according to the positive current or the negative current.

[0053] When the current flows from V SW Flowing to ground (current I MB direction is positive), V A =V B , causing the forward current I SHP With down tube M B Current I MB Then, the forward current I SHP The second current mirror module sends the current to the sampling module, and the sampling resistor R SNS The voltage V REF Provides bias, generating a voltage V at the output node ISNS .

[0054] When current flows from ground to V SW (Current I MB direction is negative), V A =V B , causing the negative current I SHN With down tube M B Current I MB Then, the negative current I SHN The second current mirror module sends the current to the sampling module, and the sampling resistor R SNS The voltage V REF Provides bias, generating a voltage V at the output node ISNS .

[0055] V ISNS =V REF +I L ×K m ×R SNS , where V REF Represents the bias voltage, I L Indicates upper tube M T The sampling current, K m Represents the internal conversion factor, R SNSIndicates the resistance of the sampling resistor.

[0056] In summary, the current sampling method provided in the embodiment of the present application requires temperature compensation through a resistance compensation array when a silicon sampling tube is used to sample current from a gallium nitride power tube, so as to ensure that the on-resistance ratio of the silicon sampling tube and the gallium nitride power tube remains consistent within different temperature ranges, thereby improving the accuracy of current sampling.

[0057] When current sampling is performed on the upper tube, a first negative feedback module can be used to allow a forward current proportional to the sampling current of the upper tube to flow through the first silicon sampling lower tube and the first lower sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the positive current; or, a first negative feedback module can be used to allow a negative current proportional to the sampling current of the upper tube to flow through the first silicon sampling upper tube and the first upper sampling tube resistance compensation array, and the sampling current of the upper tube is calculated through the negative current, thereby achieving bidirectional current sampling of the upper tube.

[0058] When current sampling is performed on the lower tube, a forward current proportional to the sampling current of the lower tube can be passed through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the positive current; or, a negative current proportional to the sampling current of the lower tube can be passed through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module, and the sampling current of the lower tube is calculated through the negative current, thereby realizing bidirectional current sampling of the lower tube.

[0059] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0060] The above description is not intended to limit the embodiments of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.

Claims

1. A current sampling circuit based on a gallium nitride power tube, characterized in that: The current sampling circuit comprises an upper tube sampling circuit and a lower tube sampling circuit, wherein the upper tube sampling circuit is used to perform current sampling on the upper tube in the high-voltage switching power supply, and the lower tube sampling circuit is used to perform current sampling on the lower tube in the high-voltage switching power supply, and the upper tube and the lower tube are gallium nitride power tubes; The upper tube sampling circuit includes a first temperature compensation module, a first negative feedback module, a first current mirror module and a sampling module connected in sequence; the first temperature compensation module includes a first silicon sampling upper tube and a first upper sampling tube resistance compensation array connected, and a first silicon sampling lower tube and a first lower sampling tube resistance compensation array connected, the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the first upper sampling tube resistance compensation array and the first lower sampling tube resistance compensation array are respectively connected to the upper tube to ensure that the on-resistance ratio of the first silicon sampling upper tube to the upper tube is consistent within different temperature ranges, and the on-resistance ratio of the first silicon sampling lower tube to the upper tube is consistent; When the upper tube is turned on, the first temperature compensation module is used to make the first silicon sampling lower tube and the first lower sampling tube resistance compensation array flow a positive current proportional to the sampling current of the upper tube through the first negative feedback module, or make the first silicon sampling upper tube and the first upper sampling tube resistance compensation array flow a negative current proportional to the sampling current of the upper tube through the first negative feedback module; the first current mirror module is used to output the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module is used to calculate the sampling current of the upper tube according to the positive current or the negative current; The lower tube sampling circuit includes a second temperature compensation module, a second negative feedback module, a second current mirror module and a sampling module connected in sequence; the second temperature compensation module includes a second silicon sampling upper tube and a second upper sampling tube resistance compensation array connected, and a second silicon sampling lower tube and a second lower sampling tube resistance compensation array connected, the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are resistance arrays with negative temperature coefficients and / or positive temperature coefficients, and the second upper sampling tube resistance compensation array and the second lower sampling tube resistance compensation array are respectively connected to the lower tube to ensure that the on-resistance ratio of the second silicon sampling upper tube and the lower tube is consistent within different temperature ranges, and the on-resistance ratio of the second silicon sampling lower tube and the lower tube is consistent; When the lower tube is turned on, the second temperature compensation module is used to make the second silicon sampling lower tube and the second lower sampling tube resistance compensation array flow a positive current proportional to the sampling current of the lower tube through the second negative feedback module, or make the second silicon sampling upper tube and the second upper sampling tube resistance compensation array flow a negative current proportional to the sampling current of the lower tube through the second negative feedback module; the second current mirror module is used to output the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module is used to calculate the sampling current of the lower tube according to the positive current or the negative current.

2. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The first temperature compensation module includes a first silicon sampling upper tube, a first silicon sampling lower tube, a first upper sampling tube resistance compensation array, and a first lower sampling tube resistance compensation array; The source of the first silicon sampling upper tube is connected to the first output end of the first negative feedback module as the first input end of the first temperature compensation module; the drain of the first silicon sampling upper tube is connected to the first end of the first upper sampling tube resistance compensation array; the second end of the first upper sampling tube resistance compensation array is connected to the drain of the upper tube as the first output end of the first temperature compensation module; The drain of the first silicon sampling lower tube is connected to the second output end of the first negative feedback module as the second input end of the first temperature compensation module; the source of the first silicon sampling lower tube is connected to the first end of the first lower sampling tube resistance compensation array; the second end of the first lower sampling tube resistance compensation array is connected to the source of the upper tube as the second output end of the first temperature compensation module; The gates of the first silicon sampling upper tube and the first silicon sampling lower tube are respectively connected to the gate of the upper tube.

3. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The first negative feedback module includes a first high-bandwidth operational amplifier, a second high-bandwidth operational amplifier, a first power tube and a second power tube; The negative input terminal of the first high-bandwidth operational amplifier, the positive input terminal of the second high-bandwidth operational amplifier and the drain of the second power tube are connected to serve as the first output terminal of the first negative feedback module; The positive input terminal of the first high-bandwidth operational amplifier, the negative input terminal of the second high-bandwidth operational amplifier and the drain of the first power tube are connected to serve as the second output terminal of the first negative feedback module; The output end of the first high-bandwidth operational amplifier is connected to the gate of the first power tube and then serves as the third output end of the first negative feedback module, and is connected to the first input end of the first current mirror module; The output end of the second high-bandwidth operational amplifier is connected to the gate of the second power tube and then serves as the fourth output end of the first negative feedback module, and is connected to the second input end of the first current mirror module; The sources of the first power tube and the second power tube are respectively connected to the bootstrap voltage as input terminals of the first negative feedback module.

4. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The first current mirror module includes a third power tube, a fourth power tube, a first high-voltage tube, a first low-voltage tube, a second high-voltage tube and a second low-voltage tube; The gate of the third power tube serves as the first input end of the first current mirror module; the gate of the fourth power tube serves as the second input end of the first current mirror module; The source of the third power tube is connected to the bootstrap voltage as the third input terminal of the first current mirror module; the source of the fourth power tube is connected to the bootstrap voltage as the fourth input terminal of the first current mirror module; The drain of the third power tube is connected to the source of the first high-voltage tube; the drain of the first high-voltage tube is respectively connected to the drain and gate of the first low-voltage tube and serves as the first output end of the first current mirror module, and is connected to the first input end of the sampling module; the source of the first low-voltage tube is grounded; The gate of the first high-voltage tube is connected to the source of the upper tube; The drain of the fourth power tube is connected to the source of the second high-voltage tube; the drain of the second high-voltage tube is respectively connected to the drain and gate of the second low-voltage tube and serves as the second output end of the first current mirror module, and is connected to the second input end of the sampling module; the source of the second low-voltage tube is grounded; and the gate of the second high-voltage tube is connected to the source of the upper tube.

5. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The second temperature compensation module includes a second silicon sampling upper tube, a second silicon sampling lower tube, a second lower sampling tube resistance compensation array, and a second lower sampling tube resistance compensation array; The source of the second silicon sampling upper tube is connected to the first output end of the second negative feedback module as the first input end of the second temperature compensation module; the drain of the second silicon sampling upper tube is connected to the first end of the second lower sampling tube resistance compensation array; the second end of the second lower sampling tube resistance compensation array is connected to the drain of the lower tube as the first output end of the second temperature compensation module; The drain of the second silicon sampling lower tube is connected to the second output end of the second negative feedback module as the second input end of the second temperature compensation module; the source of the second silicon sampling lower tube is connected to the first end of the second lower sampling tube resistance compensation array; the second end of the second lower sampling tube resistance compensation array is connected to the source of the lower tube as the second output end of the second temperature compensation module; The gates of the second silicon sampling upper tube and the second silicon sampling lower tube are respectively connected to the gate of the lower tube.

6. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The second negative feedback module includes a third high-bandwidth operational amplifier, a fourth high-bandwidth operational amplifier, a fifth power tube and a sixth power tube; The negative input terminal of the third high-bandwidth operational amplifier, the positive input terminal of the fourth high-bandwidth operational amplifier and the drain of the sixth power tube are connected to serve as the first output terminal of the second negative feedback module; The positive input terminal of the third high-bandwidth operational amplifier, the negative input terminal of the fourth high-bandwidth operational amplifier and the drain of the fifth power tube are connected to serve as the second output terminal of the second negative feedback module; The output end of the third high-bandwidth operational amplifier is connected to the gate of the fifth power tube and then serves as the third output end of the second negative feedback module, and is connected to the first input end of the second current mirror module; The output end of the fourth high-bandwidth operational amplifier is connected to the gate of the sixth power tube and then serves as the fourth output end of the second negative feedback module, and is connected to the second input end of the second current mirror module; The sources of the fifth power tube and the sixth power tube are respectively connected to the bootstrap voltage as input terminals of the second negative feedback module.

7. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The second current mirror module includes a seventh power tube, an eighth power tube, a third high-voltage tube, a third low-voltage tube, a fourth high-voltage tube and a fourth low-voltage tube; The gate of the seventh power tube serves as the first input end of the second current mirror module; the gate of the eighth power tube serves as the second input end of the second current mirror module; The source of the seventh power tube is connected to the bootstrap voltage as the third input terminal of the second current mirror module; the source of the eighth power tube is connected to the bootstrap voltage as the fourth input terminal of the second current mirror module; The drain of the seventh power tube is connected to the source of the third high-voltage tube; the drain of the third high-voltage tube is respectively connected to the drain and gate of the third low-voltage tube and serves as the first output end of the second current mirror module, and is connected to the first input end of the sampling module; the source of the third low-voltage tube is grounded; the gate of the third high-voltage tube is connected to the drain of the lower tube; The drain of the eighth power tube is connected to the source of the fourth high-voltage tube; the drain of the fourth high-voltage tube is respectively connected to the drain and gate of the fourth low-voltage tube and serves as the second output end of the second current mirror module, and is connected to the second input end of the sampling module; the source of the fourth low-voltage tube is grounded; The gate electrode of the fourth high-voltage tube is connected to the drain electrode of the lower tube.

8. The current sampling circuit based on gallium nitride power tube according to claim 1, characterized in that: The sampling module includes a sample-and-hold circuit, a first current source, a second current source, a sampling resistor and a reference power supply; The first end of the sample-and-hold circuit serves as the first input end of the sampling module; the second end of the sample-and-hold circuit serves as the second input end of the sampling module; the third end of the sample-and-hold circuit is connected to the first end of the first current source; the fourth end of the sample-and-hold circuit is connected to the first end of the second current source; The second end of the first current source is connected to the internal power supply voltage; the third end of the first current source is respectively connected to the second end of the second current source and the first end of the sampling resistor; the third end of the second current source is grounded; The second end of the sampling resistor is connected to the positive electrode of the reference voltage; the negative electrode of the reference voltage is grounded.

9. The current sampling circuit based on a gallium nitride power tube according to any one of claims 1 to 8, characterized in that: When the sampling module includes a reference voltage, the voltage on the sampling resistor is equal to the reference voltage plus the sampling voltage, and the sampling voltage is equal to the product of the sampling current, the proportionality coefficient and the sampling resistor.

10. A current sampling method based on a current sampling circuit of a gallium nitride power tube, characterized in that: Used in a current sampling circuit based on a gallium nitride power tube as claimed in any one of claims 1 to 9, the method comprising: When the upper tube is turned on, the first negative feedback module causes the first silicon sampling lower tube and the first lower sampling tube resistance compensation array to flow a positive current proportional to the sampling current of the upper tube, or the first negative feedback module causes the first silicon sampling upper tube and the first upper sampling tube resistance compensation array to flow a negative current proportional to the sampling current of the upper tube; the first current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the upper tube according to the positive current or the negative current; When the lower tube is turned on, a forward current proportional to the sampling current of the lower tube flows through the second silicon sampling lower tube and the second lower sampling tube resistance compensation array through the second negative feedback module, or a negative current proportional to the sampling current of the lower tube flows through the second silicon sampling upper tube and the second upper sampling tube resistance compensation array through the second negative feedback module; the second current mirror module outputs the positive current or the negative current mirror image to the sampling resistor in the sampling module; the sampling module calculates the sampling current of the lower tube according to the positive current or the negative current.

Images