Test method for studying the effect of packaging type on the dynamic characteristics of power switch tubes

Abstract

The present invention provides a test method for studying the influence of package type on the dynamic characteristics of a power switch tube. The same Kelvin package device is taken as the device under test. When the circuit is connected, a jumper is used to respectively realize the circuit connection of a non-Kelvin package device and a Kelvin package device, and the required voltage and current signals are measured in the circuit. The method can eliminate the deviation caused by the chip packaging difference and can eliminate the influence of the common source (emitter) inductance on the driving voltage V GS and terminal voltage V DS The impact of measurement makes the measurement results more accurate and the analysis conclusions more rigorous.

Description

Technical Field

[0001] The invention relates to a testing method for studying the influence of packaging type on the dynamic characteristics of a power switch tube. Background Art

[0002] The traditional non-Kelvin package of semiconductor switching devices has three pins. Taking MOSFET as an example, there are three pins: drain (D), source (S), and gate (G). Its equivalent circuit is as follows: Figure 1 The drive circuit is connected to the G pin and the S pin, and the power circuit is connected to the D pin and the S pin.

[0003] The drive circuit and the power circuit share the source pin, and the source corresponding package parasitic inductance L S is the common source (emitter) inductance. During the switching process, the rapidly changing I DS Will be in L S A voltage drop occurs across the device, which affects the switching speed and crosstalk characteristics of the device.

[0004] With the development of technology, the switching speed of devices is getting faster and faster, and the above problems are becoming more and more serious. Various manufacturers have launched Kelvin packaging. Taking MOSFET as an example, there are four pins: drain (D), source (PS), gate (G), and Kelvin source (KS). Its equivalent circuit is as follows: Figure 2 As shown in the figure, the drive circuit is connected to the G and KS pins, and the main circuit is connected to the D and PS pins. This avoids the drive circuit and the main power commutation circuit from having a common line, achieving decoupling of the two circuits.

[0005] Non-Kelvin packages contain common source (emitter) inductance, while Kelvin packages do not. Common source (emitter) inductance can have a significant impact on the dynamic characteristics of the device, including both the switching process and the crosstalk process. The current method for studying the impact of common source (emitter) inductance on the dynamic characteristics of a device is to test and compare the same chip in a non-Kelvin package and a Kelvin package. This method is easy to implement, but there are two problems. First, due to differences in device parameters, the comparison is not rigorous and quantitative analysis cannot be performed. Second, because the measurement point includes part of the common source (emitter) inductance, the measurement results of the drive voltage VGS and terminal voltage VDS of the non-Kelvin package will deviate, leading to errors in the analysis results. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a test method for studying the influence of package type on the dynamic characteristics of power switch tubes, which can eliminate the deviation caused by chip differences and the influence of common source (emitter) inductance on the driving voltage V GS and terminal voltage V DSThe impact of measurement makes the measurement results more accurate and the analysis conclusions more rigorous.

[0007] The present invention is implemented as follows: a test method for studying the effect of package type on the dynamic characteristics of a power switch tube, taking a Kelvin package device as the device under test, specifically comprising the following steps:

[0008] When the dynamic characteristics of the Kelvin package device need to be obtained; the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, and the low output end of the drive circuit is shorted to the KS pin through the pad R2; during measurement, V GS(4-M) The measurement points are G pin and KS pin, V DS(4-M) The measurement points are D pin and KS pin; V GS(4-M) is the measured driving voltage, V DS(4-M) is the measured terminal voltage

[0009] When the dynamic characteristics of non-Kelvin packaged devices need to be obtained, the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, the low output end of the drive circuit is shorted to the PS pin through the pad R1, and the KS pin is left floating; during measurement, V GS(3-M) The measurement points are pins G and PS, which is the driving voltage measured when using a non-Kelvin package device; V GS(4in3) The measurement points are pin G and pin KS; V DS(3-M) The measurement points are pins D and PS, which are the terminal voltages measured when using non-Kelvin packaged devices; V DS(4in3) The measurement points are pin D and pin KS;

[0010] Among them, V GS(4in3) and V GS(3-M) The relationship is:

[0011] V GS(3-M) =V GS(4in3) +L S(pkg-M) ·dI DS / dt

[0012] V DS(4in3) and V DS(3-M) The relationship is:

[0013] V DS(3-M) =V DS(4in3) +L S(pkg-M) ·dI DS / dt

[0014] L S(pkg-M) The S-pole of the non-Kelvin package device is included in the package parasitic inductance between the test points; I DS is the current flowing through the device under test; dIDS / dt is I DS The time rate of change.

[0015] Furthermore, the L S(pkg-M) Obtained through impedance analyzer measurement or electromagnetic simulation software simulation.

[0016] Furthermore, the I DS The V GS(3PIN) 、V GS(3-M) 、V DS(3PIN) 、V DS(3-M) 、V GS(4-M) 、V DS(4-M) Measured using a voltage probe.

[0017] The present invention has the following advantages:

[0018] 1. The method of the present invention eliminates the influence of chip differences when comparing the dynamic characteristics of devices with two packaging forms, making the results more accurate and rigorous, and enabling quantitative analysis.

[0019] 2. The method of the present invention uses Kelvin packaged devices to obtain the switching waveforms of non-Kelvin packaged devices, and the obtained switching process driving voltage waveform and terminal voltage waveform are more accurate. It can provide correct data for the switching process analysis of the device, thereby obtaining correct conclusions. However, the driving voltage waveform and terminal voltage waveform of non-Kelvin packaged devices obtained by existing testing methods are significantly different from the actual driving voltage on the chip, which will lead to contradictions with theoretical analysis during the switching process analysis. At the same time, it is easy to mislead device research and development and circuit applications, resulting in waste of resources and project schedule delays.

[0020] 3. The method of the present invention can obtain the crosstalk waveform of non-Kelvin packaged devices with the help of Kelvin packaged devices, and the obtained crosstalk driving voltage waveform is more accurate. It can provide correct data for the crosstalk characteristic analysis of the device and the suppression of crosstalk during circuit application, so that correct conclusions can be obtained. However, the existing testing methods will cause the crosstalk driving voltage waveform of non-Kelvin packaged devices to be significantly different from the actual driving voltage waveform of the crosstalk on the chip, which will lead to contradictions with theoretical analysis when analyzing the crosstalk process. At the same time, it is easy to mislead device research and development and circuit application, resulting in waste of resources, project schedule delays or reduced circuit reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 It is the equivalent circuit diagram of non-Kelvin package in the prior art;

[0023] Figure 2 It is the equivalent circuit diagram of Kelvin package in the prior art;

[0024] Figure 3 This is the equivalent circuit diagram of the Kelvin package measurement in the present invention;

[0025] Figure 4 This is the equivalent circuit diagram of the non-Kelvin package measurement in the present invention. DETAILED DESCRIPTION

[0026] The present invention measures non-Kelvin packaged devices, and the measurement error mainly comes from I DS In L S(pkg-M) The voltage drop across the device is significant, but Kelvin packaged devices, thanks to the KS pin, do not have this problem. This problem can be solved by connecting the Kelvin packaged device to a non-Kelvin packaged device in a circuit, with the KS pin serving as the measurement pin. To eliminate the influence of chip differences on the dynamic characteristics of the device, the comparison requires using the same device and being able to implement both package types in the circuit.

[0027] In summary, the same Kelvin packaged device can be used as the device under test, and jumpers can be used to connect the circuits to achieve two package types. The details are as follows:

[0028] A test method for studying the effect of package type on the dynamic characteristics of a power switch tube uses a Kelvin packaged device as the device under test and specifically includes the following steps:

[0029] like Figure 3 As shown in the figure, when measuring a device without a common source (emitter) inductor package, that is, obtaining the dynamic characteristics of a Kelvin packaged device; the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, and the low output end of the drive circuit is shorted to the KS pin through the pad R2; during measurement, V GS(4-M) The measurement points are G pin and KS pin, V DS(4-M) The measurement points are D pin and KS pin; V GS(4-M) is the measured driving voltage, V DS(4-M) is the measured terminal voltage; the dynamic characteristics include the switching process and the crosstalk process;

[0030] like Figure 4 As shown in the figure, when measuring a device containing a common source (emitter) inductor package, that is, obtaining the dynamic characteristics of a non-Kelvin packaged device, the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, the low output end of the drive circuit is shorted to the PS pin through the pad R1, and the KS pin is left floating; during measurement, VGS(3-M) The measurement points are pins G and PS, which is the driving voltage measured when using a non-Kelvin package device; V GS(4in3) The measurement points are pin G and pin KS, V GS(4in3) is the driving voltage; V DS(3-M) The measurement points are pins D and PS, which are the terminal voltages measured when using non-Kelvin packaged devices; V DS(4in3) The measurement points are pin D and pin KS,

[0031] V DS(4in3) The terminal voltage is obtained; the pin KS is connected to the S pole of the device, and the floating KS pin is just the test point, which can eliminate the influence of the common source (emitter) inductance and obtain accurate measurement results; the dynamic characteristics include the switching process and the crosstalk process;

[0032] Among them, V GS(4in3) and V GS(3-M) The relationship is:

[0033] V GS(3-M) =V GS(4in3) +L S(pkg-M) ·dI DS / dt

[0034] V DS(4in3) and V DS(3-M) The relationship is:

[0035] V DS(3-M) =V DS(4in3) +L S(pkg-M) ·dI DS / dt

[0036] L S(pkg-M) The S-pole of the non-Kelvin package device is included in the package parasitic inductance between the test points; I DS is the current flowing through the device under test; dI DS / dt is I DS The time rate of change.

[0037] The L S(pkg-M) The impedance is measured by an impedance analyzer or obtained by electromagnetic simulation software. DS The V GS(3PIN) 、V GS(3-M) 、V DS(3PIN) 、V DS(3-M) 、V GS(4-M) 、V DS(4-M) Measured using a voltage probe.

[0038] When evaluating the switching and crosstalk characteristics of non-Kelvin packaged devices, only the following Figure 4 The connection mode is then tested, and the V GS(4-M) and V DS(4-M) , you can get a real-time curve, which can be used to accurately evaluate the switching characteristics and crosstalk characteristics.

[0039] When comparing the switching characteristics and crosstalk characteristics of devices with non-Kelvin packages and Kelvin packages, take the same Kelvin package device and use Figure 3 and Figure 4 The connection mode is then tested separately to obtain the real-time measured V GS(4-M) 、V DS(4-M) 、V GS(4in3) and V GS(3-M) , and obtain the corresponding waveform, and then accurately evaluate the switching characteristics and crosstalk characteristics.

[0040] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A test method for studying the effect of packaging type on the dynamic characteristics of a power switch tube, characterized in that: Take a Kelvin package device as the device under test, and specifically include the following steps: When the dynamic characteristics of Kelvin package devices need to be obtained; the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, and the low output end of the drive circuit is short-circuited to the KS pin through the pad R2; during measurement, V GS(4-M) The measurement points are G pin and KS pin, V DS(4-M) The measurement points are D pin and KS pin; V GS(4-M) is the measured driving voltage, V DS(4-M) is the measured terminal voltage; When the dynamic characteristics of non-Kelvin packaged devices need to be obtained, the main power circuit is connected to the D pin and PS pin of the device under test, the high output end of the drive circuit is connected to the G pin of the device under test, the low output end of the drive circuit is short-circuited to the PS pin through the pad R1, and the KS pin is left floating; during measurement, V GS(3-M) The measurement points are pin G and pin PS, which is the driving voltage measured when using a non-Kelvin package device; V GS(4in3) The measurement points are pin G and pin KS; V DS(3-M) The measurement points are pin D and pin PS, which is the terminal voltage measured when using a non-Kelvin package device; V DS(4in3) The measurement points are pin D and pin KS; Among them, V GS(4in3) and V GS(3-M) The relationship is: IN GS(3-M) =V GS(4in3) +L S(pkg-M) ·dI DS / dt V DS(4in3) and V DS(3-M) The relationship is: IN DS(3-M) =V DS(4in3) +L S(pkg-M) ·dI DS / dt L S(pkg-M) I is the package parasitic inductance of the non-Kelvin package device where the S pole is included between the test points; DS is the current flowing through the device under test; dI DS / dt is I DS The time rate of change.

2. A test method for studying the effect of packaging type on the dynamic characteristics of a power switch tube as claimed in claim 1, characterized in that: The L S(pkg-M) Obtained through impedance analyzer measurement or electromagnetic simulation software simulation.

3. A test method for studying the effect of packaging type on the dynamic characteristics of a power switch tube according to claim 1, characterized in that: I DS is obtained by measuring using a current probe, a Rogowski coil, a current waveform analyzer or a sampling resistor; the V GS(4IN3) 、V GS(3-M) 、V DS(4IN3) 、V DS(3-M) 、V GS(4-M) 、V DS(4-M) Measured using a voltage probe.

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