Temperature measuring system and measuring method for high-power pulse amplifier

Abstract

The invention discloses a temperature measurement system and method for a high-power pulse amplifier, and solves the problems that the high-power pulse amplifier is large in gate leakage current, affects the gate voltage, affects the drain current through a trap effect, and enables the temperature not to be a single variable of the drain current. The temperature change is difficult to accurately reflect by measuring the drain current; the influence of the gate leakage current on the gate voltage is reduced by changing the series resistance and the ground parallel capacitance on the gate modulation circuit, so that the temperature becomes the unique variable of the drain current change, and then the magnitude of the drain current of the pulse power amplifier is measured through the current clamp. And calculating the surface temperature of the tube core of the high-power pulse amplifier according to the relationship between the instantaneous drain current and the surface temperature of the tube core of the high-power pulse amplifier. The method solves the problem that the surface temperature of the tube core of the high-power pulse amplifier is influenced by multivariable in a traditional electrical temperature measurement method, and has the advantages of rapid temperature measurement and capability of being applied to temperature measurement in different temperature environments.

Description

Technical Field

[0001] The invention relates to a temperature measurement method for a power device, and in particular to a temperature measurement system and a temperature measurement method for a high-power pulse amplifier. Background Art

[0002] As the third-generation semiconductor material GaN process matures, the output power of microwave power amplifiers continues to increase. At present, the output power of devices has exceeded the kW level. The paper "AkW-class AlGaN / GaN HEMT Pallet Amplifier for S-band High Power Application" published by E. Mitani et al. in 2007 and the paper "Kilowatt-level power amplifier in a single-ended architecture at 352MHz" published by L. Haapala et al. in 2016 both recorded kW-level power amplifiers. High-power pulse amplifiers have a self-heating effect when working, and it increases with the increase of power. In the working pulse, the heat accumulation effect at the device die causes the temperature to gradually increase over time, which causes the mobility of the two-dimensional electron gas (2DEG) in the channel to decrease, thereby causing the drain current to decrease. Therefore, the temperature of the active area can be characterized by measuring the drain current.

[0003] There are three main methods for measuring the temperature of GaN HEMT. 1) Optical temperature measurement method, which is measured by infrared thermal imaging, Raman spectroscopy and other methods. The advantage of this method is that it can directly measure the temperature data of the active area. The disadvantage is that it requires a larger gate-drain gap, and the instrument with higher spatial resolution and time resolution has higher requirements for the test environment; 2) Finite element simulation analysis method, but due to the inaccuracy of material parameters and structure and the uneven distribution of heat sources, there is a large gap between the thermal simulation results and experimental tests. At the same time, the size of kW-level GaN HEMT devices is getting smaller and smaller. The Fourier law used in the current mainstream thermal simulation software has certain limitations at the micro-nano scale, and it is difficult to accurately predict the heat transfer process. 3) Electrical measurement method, which indirectly measures the temperature based on the sensitivity of electrical parameters to temperature, usually through electrical parameters with high temperature sensitivity such as threshold voltage and drain current. The advantage of the electrical measurement method is that it can be quickly measured through standard equipment, and does not require direct contact with the power amplifier. However, high-power pulse amplifiers have many influencing factors, such as large gate leakage current affecting gate voltage and trap effect affecting drain current. As a result, temperature is no longer a single variable of drain current, and it is difficult to accurately reflect temperature changes by measuring drain current. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that a high-power pulse amplifier has a large gate leakage current, which affects the gate voltage, and the trap effect affects the drain current, so that the temperature is no longer a single variable of the drain current, and it is difficult to accurately reflect the temperature change by measuring the drain current. A temperature measurement system and measurement method for a high-power pulse amplifier are provided.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] The present invention provides a temperature measurement system for a high power pulse amplifier, which has the following characteristics:

[0007] It includes a gate debugging module, a drain current curve measurement module, a power amplifier tube surface temperature measurement module and a data processing module;

[0008] The gate debugging module is connected to the gate of the high-power pulse amplifier, and is used to reduce the influence of the gate leakage current on the gate voltage in the high-power pulse amplifier;

[0009] The drain current curve measurement module is connected to the drain of the high-power pulse amplifier and is used to measure the transient curve of the drain current;

[0010] The power amplifier tube surface temperature measurement module is used to measure the surface temperature curve of the high-power pulse amplifier tube core;

[0011] The input end of the data processing module is respectively connected to the output end of the drain current curve measurement module and the output end of the power amplifier tube surface temperature measurement module. The data processing module is used to fit the drain current transient curve and the surface temperature curve of the high-power pulse amplifier tube core to obtain a current change formula or curve with temperature.

[0012] Furthermore, the gate debugging module is a PCB bias circuit with capacitors and resistors.

[0013] Further, the gate debugging module includes a low-voltage DC power supply and a gate bias circuit;

[0014] The gate bias circuit includes an adjustable parallel capacitor to ground Cg and an adjustable resistor Rg, wherein the positive plate of the adjustable parallel capacitor to ground Cg and one end of the adjustable resistor Rg are both connected to a low-voltage DC power supply; the negative plate of the adjustable parallel capacitor to ground Cg is grounded, and the other end of the adjustable resistor Rg is connected to the gate of the high-power pulse amplifier.

[0015] Further, the drain current curve measurement module includes a high-voltage DC power supply, a pulse modulation circuit, a pulse generator, an oscilloscope, a current clamp, an inductor Lline and a drain bias circuit;

[0016] The positive terminal of the high-voltage DC power supply is connected to the pulse modulation circuit, and is used to provide high-voltage DC power to the pulse modulation circuit;

[0017] The control end of the pulse modulation circuit is connected to a pulse generator;

[0018] The output end of the pulse modulation circuit is connected to one end of the inductor Lline, and the other end of the inductor Lline is connected to the drain bias circuit;

[0019] The drain bias circuit is connected to the drain of the high power pulse amplifier;

[0020] The input end of the current clamp is connected to the connection point between the other end of the inductor Lline and the drain bias circuit, and the output end is connected to the oscilloscope.

[0021] Further, the drain bias circuit includes a parasitic inductance Lb and a parallel capacitor Cb to ground;

[0022] One end of the parasitic inductor Lb is connected to the other end of the inductor Lline, and the other end is connected to the drain of the high-power pulse amplifier and the positive plate of the parallel capacitor Cb to the ground;

[0023] The negative plate of the ground parallel capacitor Cb is grounded.

[0024] Furthermore, the power amplifier tube surface temperature measurement module includes an infrared temperature detector and a temperature-adjustable heat stage;

[0025] The hot stage is connected to the high-power pulse amplifier through a test fixture, and thermal grease is applied to the bottom of the test fixture, and the initial temperature of the high-power pulse amplifier is adjusted by adjusting the temperature of the hot stage;

[0026] The infrared temperature detector is arranged above the heat stage and facing the high power pulse amplifier, and is used to measure the surface temperature of the high power pulse amplifier tube core on the heat stage. The output end of the infrared temperature detector is connected to the other input end of the data processing module.

[0027] A temperature measurement method for a high-power pulse amplifier is special in that it is based on the above-mentioned temperature measurement system for a high-power pulse amplifier and includes the following steps:

[0028] Step 1, connect the temperature measurement system for the high-power pulse amplifier to the high-power pulse amplifier, turn on the high-power pulse amplifier, collect the gate voltage curve, and adjust the gate debugging module so that the gate voltage curve is a horizontal straight line;

[0029] Step 2, measuring the drain current transient curve of the high power pulse amplifier by using a drain current curve measurement module;

[0030] Step 3, using a power amplifier tube surface temperature measurement module to measure the surface temperature curve of the high power pulse amplifier tube core;

[0031] Step 4, fitting the transient curve of the drain current and the surface temperature curve of the high-power pulse amplifier die to obtain a current-temperature variation formula and curve;

[0032] Step 5: Collect the transient drain current of the high-power pulse amplifier whose temperature is to be measured, and obtain the surface temperature of the high-power pulse amplifier die by combining the current-temperature variation formula or curve.

[0033] Furthermore, in step 1, the gate voltage curve is made to be a horizontal straight line by adjusting the adjustable resistor Rg and the adjustable parallel capacitor Cg to ground in the gate debugging module.

[0034] Beneficial effects of the present invention:

[0035] The present invention provides a temperature measurement system and method for a high-power pulse amplifier. The instantaneous drain current of the pulse power amplifier is measured by a current clamp, and the surface temperature of the core tube of the high-power pulse amplifier is obtained according to the relationship between the instantaneous drain current and the surface temperature of the core tube of the high-power pulse amplifier. The inventive method overcomes the disadvantage that the temperature of the traditional electrical temperature measurement method is affected by multiple variables, has the advantages of rapid temperature measurement and can be applied to temperature measurement in different temperature environments, and therefore has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of a gate debugging module and a drain current curve measurement module in an embodiment of a temperature measurement system for a high-power pulse amplifier of the present invention;

[0037] Figure 2 It is a structural schematic diagram of a power amplifier tube surface temperature measurement module in an embodiment of a temperature measurement system for a high-power pulse amplifier of the present invention;

[0038] Figure 3 A schematic diagram of transient state of drain current and surface temperature change of a high-power pulse amplifier die in an embodiment of a temperature measurement method for a high-power pulse amplifier of the present invention;

[0039] Figure 4 It is a schematic diagram of the absolute error between the drain current measured and the current fitted by the formula at different ambient temperatures in an embodiment of a temperature measurement method for a high-power pulse amplifier of the present invention;

[0040] Figure 5 The figure is a schematic diagram of the relative error between the drain current measured and the current fitted by the formula at different ambient temperatures in an embodiment of a temperature measurement system for a high-power pulse amplifier of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The drain peak current of the high power pulse amplifier of this embodiment is 140-200A, the pulse width is 1-10μs, and the pulse repetition frequency is 1-150Hz.

[0043] On this basis, this embodiment provides a temperature measurement system for a high-power pulse amplifier, which reduces the influence of gate leakage current on gate voltage by changing the series resistance and the parallel capacitance to ground on the gate modulation circuit, so that temperature becomes the only variable of drain current change. Therefore, the transient temperature change curve of the active area of ​​the high-power amplifier can be obtained by measuring the drain current change curve, so as to achieve the purpose of quickly measuring channel temperature under different ambient temperatures; the temperature measurement system of the present invention includes a gate debugging module, a drain current curve measurement module, a power amplifier tube surface temperature measurement module and a data processing module;

[0044] The gate debugging module is connected to the gate of the high-power pulse amplifier and is used to reduce the influence of the gate leakage current on the gate voltage in the high-power pulse amplifier;

[0045] In this embodiment, the gate debugging module is a PCB bias circuit with capacitors and resistors.

[0046] like Figure 1 As shown, the gate debugging module includes a low-voltage DC power supply and a gate bias circuit;

[0047] The gate bias circuit includes an adjustable parallel capacitor Cg to ground and an adjustable resistor Rg. The positive plate of the adjustable parallel capacitor Cg to ground and one end of the adjustable resistor Rg are both connected to a low-voltage DC power supply; the negative plate of the adjustable parallel capacitor Cg to ground is grounded, and the other end of the adjustable resistor Rg is connected to the gate of the high-power pulse amplifier.

[0048] The drain current curve measurement module is connected to the drain of the high power pulse amplifier to measure and display the transient curve of the drain current; Figure 1As shown, it includes a high-voltage DC power supply, a pulse modulation circuit, a pulse generator, an oscilloscope, a current clamp, an inductor Lline and a drain bias circuit; the positive end of the high-voltage DC power supply is connected to the pulse modulation circuit, which is used to provide high-voltage DC power to the pulse modulation circuit; the control end of the pulse modulation circuit is connected to the pulse generator; the output end of the pulse modulation circuit is connected to one end of the inductor Lline, and the other end of the inductor Lline is connected to the drain bias circuit; the drain bias circuit is connected to the drain of the high-power pulse amplifier, the input end of the current clamp is connected to the connection between the other end of the inductor Lline and the drain bias circuit, and the output end is connected to the oscilloscope.

[0049] In this embodiment, the drain bias circuit includes a parasitic inductor Lb, one end of which is connected to the other end of the inductor Lline, and the other end is connected to the drain of the high-power pulse amplifier and the positive plate of the parallel capacitor Cb to ground; the negative plate of the parallel capacitor Cb to ground is grounded.

[0050] The power amplifier tube surface temperature measurement module is arranged just above the high-power pulse amplifier and is used to measure the surface temperature curve of the high-power pulse amplifier tube core; Figure 2 As shown, the power amplifier tube surface temperature measurement module includes an infrared temperature detector and a temperature-adjustable hot stage; the hot stage is connected to the high-power pulse amplifier through a test fixture, and thermal grease is applied to the bottom of the test fixture, and the initial temperature of the high-power pulse amplifier is adjusted by adjusting the temperature of the hot stage; the infrared temperature detector is arranged above the hot stage and facing the high-power pulse amplifier, and is used to measure the surface temperature of the high-power pulse amplifier tube core on the hot stage.

[0051] The data processing module is used to input the transient curve of drain current and the surface temperature curve of the high-power pulse amplifier tube core, and fit the transient curve of drain current and the surface temperature curve of the high-power pulse amplifier tube core to obtain the current variation with temperature formula and curve.

[0052] Firstly, the relationship between the drain current of the high power pulse amplifier and the surface temperature of the high power pulse amplifier die is analyzed. From formula (1), it can be known that the physical quantities that change with temperature are the electron mobility μ(T) and the threshold voltage VT(T).

[0053]

[0054] Electron mobility decreases as temperature increases, and its variation with temperature can be described as:

[0055]

[0056] Where T is the surface temperature of the high power pulse amplifier die, T0 is the ambient temperature, and k1 is a constant. The threshold voltage of the high power pulse amplifier decreases almost linearly with increasing temperature, which can be described as:

[0057] V T (T) = V T (T 0 )-k 2 (TT 0 ) (3)

[0058] Therefore, as temperature increases, the drain current decreases as carrier mobility decreases, and increases as the threshold voltage decreases.

[0059] Optimize the gate bias circuit, change the series resistance and parallel capacitance to ground of the gate bias circuit, and use an oscilloscope to monitor the change of the gate voltage until the gate voltage has no obvious change, so as to reduce the impact of gate voltage jitter on the drain current.

[0060] For kW-class GaN HEMT devices, the drain current is generally tens to hundreds of amperes. The main reason for the change in drain current is carrier mobility, and the change in threshold voltage is relatively negligible. The main reason for the change in drain current is carrier mobility. Therefore, the relationship between drain current and temperature can be expressed as:

[0061]

[0062] A current clamp for measuring the drain current is placed at the connection between the inductor Lds and the output end of the pulse modulation circuit. The current clamp is connected to an oscilloscope, and the measurement results of the current clamp are displayed on the oscilloscope. The schematic diagram of the drain current test system is shown in Figure 1. Figure 1 shown.

[0063] Substituting the high power pulse amplifier drain current measurement results and temperature measurement results into formula (4) to obtain the k value, the fitting formula of the drain current and the surface temperature of the high power pulse amplifier core tube can be deduced.

[0064] The inventive method compares the drain current versus temperature curve measured at different ambient temperatures with the drain current versus temperature relationship fitted by formula (4), and finds that the curves are almost identical. Therefore, an effective conclusion can be drawn: after calibrating the drain current and the surface temperature of the high-power pulse amplifier die at any ambient temperature, the surface temperature of the high-power pulse amplifier die, i.e., the channel temperature of the high-power pulse amplifier, can be calculated by measuring the drain transient current of the power amplifier, thereby realizing the measurement of the surface temperature of the high-power pulse amplifier die at different ambient temperatures, and estimating the maximum operating pulse width at any ambient temperature, thereby ensuring that the high-power pulse amplifier operates within a safe and reliable operating temperature range.

[0065] Based on the above analysis, this embodiment also provides a temperature measurement method for a high power pulse amplifier, comprising the following steps:

[0066] Step 1, connect the temperature measurement system for the high-power pulse amplifier to the high-power pulse amplifier, turn on the high-power pulse amplifier, collect the gate voltage curve, and adjust the gate debugging module so that the gate voltage curve is a horizontal straight line;

[0067] Step 2, measuring the drain current transient curve of the high power pulse amplifier by using a drain current curve measurement module;

[0068] Step 3, using a power amplifier tube surface temperature measurement module to measure the surface temperature curve of the high power pulse amplifier tube core;

[0069] Step 4, fitting the transient curve of the drain current and the surface temperature curve of the high-power pulse amplifier die to obtain a current-temperature variation formula and curve;

[0070] Step 5: Collect the transient drain current of the high-power pulse amplifier whose temperature is to be measured, and obtain the surface temperature of the high-power pulse amplifier die by combining the current-temperature variation formula or curve.

[0071] The temperature measurement system and method for a high-power pulse amplifier in this embodiment are used to measure the surface temperature of the core tube of the high-power pulse amplifier. The bottom of the high-power pulse amplifier test fixture is coated with thermal grease and placed on a hot stage of an infrared temperature detector. At hot stage temperatures of 45°C, 60°C, and 80°C, the core temperature T(t) of the power amplifier in a DC working state with different working pulse widths is measured over time t.

[0072] At 45°C, 60°C and 80°C hot stage temperatures, the drain current I(t) of the high power pulse amplifier at different pulse widths is measured versus time t, and the measurement results are displayed on an oscilloscope.

[0073] The initial time t 0 At the same time t 1 The measured high power pulse amplifier drain current I(t 0 )、I(t 1 ) and temperature measurement result T(t 0 )、T(t 1 ) into formula (4) to get the k value. Substitute the k value into the formula to calculate the fitting value of the drain current under different pulse widths. The fitting value curve is compared with the drain current measurement curve of the high-power pulse amplifier under different drain voltage pulse widths measured at 45℃, 60℃ and 80℃ hot stage temperatures. The comparison results are shown in Figure 3 The formula fitting current is compared with the drain current data measured at different ambient temperatures. The absolute error is less than 1.5A and the relative error is less than 1%. The absolute error and relative error results are shown in Figure 4 , Figure 5According to the test results, the surface temperature of the high-power pulse amplifier die can be calculated by measuring the instantaneous value of the drain current at different ambient temperatures.

[0074] Through the above analysis, it can be known that by using the temperature measurement system and measurement method for a high-power pulse amplifier of the present invention to measure the surface temperature of the core tube of the high-power pulse amplifier, rapid and accurate temperature measurement of the active area under different ambient temperatures can be achieved, so that the core tube of the high-power pulse amplifier can operate within a safe and reliable temperature range.

[0075] The above description is only a specific embodiment of the present invention, and a comparison of the effects of the specific embodiments and the related comparative examples, but the protection scope of the present invention is not limited thereto, and any changes or substitutions within the technical scope disclosed by the present invention shall be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A temperature measurement system for a high power pulse amplifier, characterized in that: It includes a gate debugging module, a drain current curve measurement module, a power amplifier tube surface temperature measurement module and a data processing module; The gate debugging module is connected to the gate of the high-power pulse amplifier, and is used to reduce the influence of the gate leakage current on the gate voltage in the high-power pulse amplifier; The drain current curve measurement module is connected to the drain of the high-power pulse amplifier and is used to measure the transient curve of the drain current; The power amplifier tube surface temperature measurement module is used to measure the surface temperature curve of the high-power pulse amplifier tube core; The data processing module is used to fit the transient curve of the drain current and the surface temperature curve of the high-power pulse amplifier tube core to obtain a current-temperature variation formula or curve.

2. A temperature measurement system for a high power pulse amplifier according to claim 1, characterized in that: The gate debugging module is a PCB bias circuit with capacitors and resistors.

3. A temperature measurement system for a high power pulse amplifier according to claim 2, characterized in that: The gate debugging module includes a low-voltage DC power supply and a gate bias circuit; The gate bias circuit includes an adjustable parallel capacitor to ground Cg and an adjustable resistor Rg, wherein the positive plate of the adjustable parallel capacitor to ground Cg and one end of the adjustable resistor Rg are both connected to a low-voltage DC power supply; the negative plate of the adjustable parallel capacitor to ground Cg is grounded, and the other end of the adjustable resistor Rg is connected to the gate of the high-power pulse amplifier.

4. The temperature measurement system for a high power pulse amplifier according to claim 1, characterized in that: The drain current curve measurement module includes a high-voltage DC power supply, a pulse modulation circuit, a pulse generator, an oscilloscope, a current clamp, an inductor Lline and a drain bias circuit; The positive terminal of the high-voltage DC power supply is connected to the pulse modulation circuit, and is used to provide high-voltage DC power to the pulse modulation circuit; The control end of the pulse modulation circuit is connected to a pulse generator; The output end of the pulse modulation circuit is connected to one end of the inductor Lline, and the other end of the inductor Lline is connected to the drain bias circuit; The drain bias circuit is connected to the drain of the high power pulse amplifier; The input end of the current clamp is connected to the connection point between the other end of the inductor Lline and the drain bias circuit, and the output end is connected to the oscilloscope.

5. A temperature measurement system for a high power pulse amplifier according to claim 4, characterized in that: The drain bias circuit includes a parasitic inductor Lb and a parallel capacitor Cb to ground; One end of the parasitic inductor Lb is connected to the other end of the inductor Lline, and the other end is connected to the drain of the high-power pulse amplifier and the positive plate of the parallel capacitor Cb to the ground; The negative plate of the ground parallel capacitor Cb is grounded.

6. The temperature measurement system for a high power pulse amplifier according to claim 1, characterized in that: The power amplifier tube surface temperature measurement module includes an infrared temperature detector and a temperature-adjustable heat stage; The hot stage is connected to the high-power pulse amplifier through a test fixture, and thermal grease is applied to the bottom of the test fixture, and the initial temperature of the high-power pulse amplifier is adjusted by adjusting the temperature of the hot stage; The infrared temperature detector is arranged above the heat stage and facing the high power pulse amplifier, and is used to measure the surface temperature of the high power pulse amplifier tube core on the heat stage. The output end of the infrared temperature detector is connected to the other input end of the data processing module.

7. A temperature measurement method for a high power pulse amplifier, characterized in that: A temperature measurement system for a high power pulse amplifier according to any one of claims 1 to 6, comprising the following steps: Step 1, connect the temperature measurement system for the high-power pulse amplifier to the high-power pulse amplifier, turn on the high-power pulse amplifier, collect the gate voltage curve, and adjust the gate debugging module so that the gate voltage curve is a horizontal straight line; Step 2, measuring the drain current transient curve of the high power pulse amplifier by using a drain current curve measurement module; Step 3, using a power amplifier tube surface temperature measurement module to measure the surface temperature curve of the high power pulse amplifier tube core; Step 4, fitting the transient curve of the drain current and the surface temperature curve of the high power pulse amplifier die to obtain a current-temperature variation formula and curve; Step 5: Collect the transient drain current of the high-power pulse amplifier whose temperature is to be measured, and obtain the surface temperature of the high-power pulse amplifier die by combining the current-temperature variation formula or curve.

8. A temperature measurement method for a high power pulse amplifier according to claim 7, characterized in that: In step 1, the gate voltage curve is made to be a horizontal straight line by adjusting the adjustable resistor Rg and the adjustable parallel capacitor Cg to ground in the gate debugging module.

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