A semiconductor power module detection circuit

Abstract

The present invention provides a semiconductor power module detection circuit, which relates to the technical field of semiconductor power modules and includes a constant current source circuit, a sampling circuit, and a frequency conversion circuit connected to a temperature sensor; wherein, the temperature sensor is a diode-type sensor; the constant current source circuit is connected to a first amplifier through a power supply voltage input terminal so as to output a stable current to the temperature sensor; the sampling circuit processes the output of the temperature sensor through a second amplifier to obtain a sampling voltage; under the frequency conversion circuit, the sampling voltage is input into a third amplifier, and according to the high and low level conversion voltage thresholds generated by the connection circuit on the third amplifier, a discharge circuit or a charging circuit is formed through a first capacitor connected to the third amplifier, and a frequency signal is output according to the conversion time of the discharge circuit or the charging circuit, solving the problem that the existing voltage-frequency conversion circuit for NTC temperature sensors cannot be applied to diode temperature sensors.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor modules, and particularly to a semiconductor power module detection circuit. Background Art

[0002] As a core device in an electronic system, a power module often operates in an environment of high voltage and large current, and the quality of its performance directly affects the reliability of the electronic system. Therefore, testing various electrical parameters of the power module and eliminating unqualified products are of great significance for improving the reliability of the system, especially for the temperature test of the semiconductor module.

[0003] In existing modules with a temperature sensor of the type of thermistor diode, temperature sampling is performed through a built-in constant current source and a driving chip of the detection circuit. If the driving chip used in the electronic control cannot provide a constant current source and detection function, a detection circuit needs to be built. Currently, the low-cost detection circuit for NTC resistors built with discrete devices is a voltage-frequency conversion circuit. In this detection method, the current flowing through the temperature sensor in the loop is variable. If a module with a diode-type temperature sensor applies such a voltage-frequency conversion circuit to detect the module temperature, the sampling error is large or it cannot be used. Summary of the Invention

[0004] In order to overcome the above technical defects, the purpose of the present invention is to provide a semiconductor power module detection circuit to solve the problem that the existing voltage-frequency conversion circuit for NTC temperature sensors cannot be applied to diode temperature sensors.

[0005] The present invention discloses a semiconductor power module detection circuit,

[0006] including a constant current source circuit, a sampling circuit, and a frequency conversion circuit connected to a temperature sensor; wherein, the temperature sensor is a diode-type sensor;

[0007] The constant current source circuit is connected to a first amplifier through a power supply voltage input terminal, so as to output a stable current to the temperature sensor;

[0008] The sampling circuit processes the output of the temperature sensor through a second amplifier to obtain a sampling voltage;

[0009] Under the frequency conversion circuit, the sampling voltage is input into a third amplifier, and according to the high and low level conversion voltage thresholds generated by the connection circuit on the third amplifier, a discharge circuit or a charging circuit is formed through a first capacitor connected to the third amplifier, and a frequency signal is output according to the conversion time of the discharge circuit or the charging circuit

[0010] Preferably, the constant current source circuit includes a first resistor and a second resistor connected in parallel;

[0011] The input terminal of the first resistor is connected to the power supply voltage input terminal, and the output terminal is connected to the second resistor and the first amplifier;

[0012] The temperature sensor is connected in series with the first amplifier to input a stable current.

[0013] Preferably, in the sampling circuit, the temperature sensor connected in series with the second amplifier is sampled and gain-processed by adjusting the resistor connected to the second amplifier, and the sampling voltage is obtained from the output terminal of the second amplifier.

[0014] Preferably, when it is determined based on the sampling voltage and the high and low level conversion voltage threshold that the inverting input terminal of the third amplifier inputting the sampling voltage is at a low level relative to the non-inverting input terminal of the third amplifier, a charging circuit is formed;

[0015] When it is determined based on the sampling voltage and the high and low level conversion voltage threshold that the inverting input terminal of the third amplifier inputting the sampling voltage is at a high level relative to the non-inverting input terminal of the third amplifier, a discharging circuit is formed;

[0016] In the charging circuit, the first capacitor is charged through the third resistor connected in series between the second amplifier and the third amplifier;

[0017] In the discharging circuit, the first capacitor is discharged through the seventh resistor provided in the connection circuit.

[0018] Preferably, the connection circuit on the third amplifier includes a first control circuit for forming a charging circuit and a second control circuit for forming a discharging circuit;

[0019] The first control circuit includes a fourth resistor, and a fifth resistor and a sixth resistor connected in series / parallel with the fourth resistor,

[0020] The second control circuit includes a seventh resistor connected in series with the third amplifier and a diode for reverse current protection.

[0021] Preferably, in the first control circuit, the circuit formed by the parallel connection of the fourth resistor and the sixth resistor and then connected in series with the fifth resistor calculates the high level conversion voltage threshold for forming a discharging circuit based on the power supply voltage; the circuit formed by the parallel connection of the fourth resistor and the fifth resistor and then connected in series with the sixth resistor calculates the low level conversion threshold for forming a charging circuit based on the power supply voltage to obtain the high and low level conversion thresholds.

[0022] Preferably, according to the first capacitor, the third resistor, and the high and low level conversion thresholds, the time when the inverting input terminal of the third amplifier in the charging circuit reaches the same level as the non-inverting input terminal of the third amplifier is determined to obtain the time of the charging circuit;

[0023] Determine the time when the non-inverting input terminal of the third amplifier in the discharge circuit reaches the same level as the inverting input terminal of the third amplifier according to the first capacitor, the seventh resistor, and the determined high and low level conversion threshold, and obtain the time of the discharge circuit;

[0024] Determine the conversion time of the discharge circuit or the charging circuit according to the time of the charging circuit and the time of the discharge circuit.

[0025] Preferably, output a frequency signal according to the reciprocal of the sum of the time of the discharge circuit and the time of the charging circuit.

[0026] Preferably, the time of the charging circuit changes as the sampling voltage changes due to temperature caused by temperature sensing;

[0027] The time of the discharge circuit remains unchanged.

[0028] Preferably, the detection circuit is connected to the power chip of the lower bridge arm in the semiconductor power module.

[0029] After adopting the above technical solutions, compared with the prior art, the following beneficial effects are obtained:

[0030] The detection circuit provided by this application has a constant current source design, which makes the input current of the temperature sensor stable, so it is applicable to the sensors of the temperature diode type built in the packaging module. After applying the constant current source, sampling is carried out. Compare the sampling voltage output by the sampling circuit with the high and low level conversion voltage conversion threshold. According to the high and low level change on the output side of the third amplifier, determine whether the first capacitor is charged or discharged, and perform the conversion between the discharge circuit / charging circuit. Output a frequency signal as the output of this detection circuit according to the time of the circuit conversion, and determine the change of the temperature sensor through the output time / frequency signal, so as to solve the problem that the existing voltage-frequency conversion circuit for NTC temperature sensors cannot be applied to diode temperature sensors. Description of the Drawings

[0031] Figure 1 It is a circuit schematic diagram of an embodiment of a semiconductor power module detection circuit described in the present invention;

[0032] Figure 2 It is a circuit schematic diagram of an embodiment of a semiconductor power module detection circuit described in the present invention connected to a drive chip. Detailed Embodiments

[0033] The advantages of the present invention are further elaborated below in conjunction with the drawings and specific embodiments.

[0034] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0035] The terms used in this disclosure are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0036] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0037] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0038] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, they may be mechanically connected or electrically connected, or may be the internal communication of two elements. They may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms may be understood according to specific circumstances.

[0039] In the following description, the suffixes such as "module", "component", or "unit" used to represent elements are only for the convenience of describing the present invention, and they do not have a specific meaning in themselves. Therefore, "module" and "component" may be used interchangeably.

[0040] Embodiment: This embodiment discloses a semiconductor power module detection circuit. Refer to Figure 1 and2 , including a constant current source circuit, a sampling circuit, and a frequency conversion circuit connected to a temperature sensor in a semiconductor module; wherein, the temperature sensor is a diode-type sensor (D_sensor). It should be noted that the above temperature sensor is different from the existing NTC sensors. It does not change its resistance but changes the change in the diode voltage drop caused by different temperatures. The existing voltage-frequency conversion circuit for NTC temperature sensors cannot be applied to this diode temperature sensor. Specifically, the detection circuit is used to be connected to the lower bridge arm of a power chip (driver chip). Each power chip can be correspondingly connected to a detection circuit, rather than being directly built inside the power chip as in the existing ones, without considering the internal layout and space of the chip.

[0041] Specifically, the constant current source circuit is connected to a first amplifier through a power supply voltage (VCC) input terminal, so as to output a stable current to the temperature sensor; the constant current source circuit includes a first resistor (R09) and a second resistor (R10) connected in parallel; the input terminal of the first resistor is connected to the power supply voltage input terminal, and the output terminal is connected to the second resistor and the first amplifier. One end of the second resistor is connected in series between the first resistor and the first amplifier, and the other end is grounded; the temperature sensor is connected in series with the first amplifier to input a stable current. The first resistor and the second resistor are connected to the positive input terminal of the first amplifier, and the temperature sensor is connected between the negative input terminal and the output terminal of the first amplifier. Specifically, the voltage V1 at the positive input terminal of the first amplifier There is also an auxiliary resistor R11 with one end connected in series with the temperature sensor to the negative input terminal of the first amplifier and the other end grounded. According to this auxiliary resistor, the specific stable current I passing through the temperature sensor can be determined.

[0042] Based on the above, the output of the temperature sensor is processed by the sampling circuit through a second amplifier to obtain a sampling voltage; specifically, in the sampling circuit, by adjusting the resistor connected to the second amplifier, the temperature sensor connected in series with the second amplifier is sampled and gain-processed, and the sampling voltage is obtained from the output terminal of the second amplifier. The output V2 of the above temperature sensor, V2 = V1 + V D ; V D is the voltage output by the temperature sensor based on the above stable current. By adjusting the resistor in the above sampling circuit, the amplification gain is obtained as V3. The purpose is to improve the resolution of the circuit and improve the sampling accuracy. Specifically, the adjusting resistor includes a resistor R03 connected between the first amplifier and the second amplifier. This resistor R03 is connected to the positive input terminal of the second amplifier. It also includes resistors R02 and R01 connected in series at the output terminal of the second amplifier. The other end of R01 is grounded, and the negative input terminal of the second amplifier is connected between R02 and R01. Based on the setting of this sampling circuit, its output sampling voltage V3 is

[0043] Based on the above, under the frequency conversion circuit, the sampled voltage is input into the third amplifier, and according to the high and low level conversion voltage thresholds generated by the connection circuit on the third amplifier, a discharge circuit or a charging circuit is formed through the first capacitor connected to the third amplifier, and a frequency signal is output according to the conversion time of the discharge circuit or the charging circuit. It should be noted that the above high and low level conversion voltage thresholds are preset according to the range of the sampled voltage output above, that is, they can be set according to the parameters of the temperature sensor (i.e., D_sensor) and are realized through the connection circuit connected to the above third amplifier.

[0044] In the above embodiment, the connection circuit on the third amplifier includes a first control circuit for forming a charging circuit and a second control circuit for forming a discharge circuit; the first control circuit includes a fourth resistor (R04), and a fifth resistor (R07) and a sixth resistor (R06) connected in series / parallel with the fourth resistor. More specifically, the fourth resistor is connected in parallel with the fifth resistor and then in series with the sixth resistor. The fourth resistor is connected to the positive input terminal and the output terminal of the third amplifier. One end of the fifth resistor is also connected to the 5V power supply, and one end of the sixth resistor is grounded to form a low-level charging circuit. A capacitor C02 can also be connected in parallel with the sixth resistor to further improve the stability of the flip threshold (high and low level conversion voltage threshold) at the output terminal of the third amplifier, etc.; the second control circuit includes a seventh resistor connected in series with the third amplifier and a diode for reverse current protection to prevent the current from flowing back into the discharge circuit when the above charging circuit is formed. The seventh resistor and the diode are connected to the output terminal and the inverting input terminal of the third amplifier and are connected to the side where the amplifier is connected to the above first capacitor to form a high-level discharge circuit.

[0045] In this embodiment, the calculation of the high and low level conversion voltage conversion threshold is as follows: In the first control circuit, the circuit formed by the parallel connection of the fourth resistor and the sixth resistor and then in series with the fifth resistor is used to calculate the high-level conversion voltage threshold for forming the discharge circuit based on the supply voltage; the circuit formed by the parallel connection of the fourth resistor and the fifth resistor and then in series with the sixth resistor is used to calculate the low-level conversion threshold for forming the charging circuit based on the supply voltage to obtain the high and low level conversion thresholds. Specifically, the high-level conversion threshold: Low-level conversion voltage threshold

[0046]

[0047] Specifically, as shown in the figure, the output of the second amplifier is connected to the third resistor (R05) and then to the inverting input terminal of the third amplifier. After comparison by the third amplifier, it flips, and the change of the high and low levels on its output side determines whether C01 is charged or discharged. When it is determined based on the sampling voltage and the high and low level conversion voltage threshold that the inverting input terminal of the third amplifier for the input sampling voltage is at a low level relative to the non-inverting input terminal of the third amplifier, a charging circuit is formed; in the charging circuit, the first capacitor (C01) is charged through the third resistor (R05) connected in series between the second amplifier and the third amplifier; when it is determined based on the sampling voltage and the high and low level conversion voltage threshold that the inverting input terminal of the third amplifier for the input sampling voltage is at a high level relative to the non-inverting input terminal of the third amplifier, a discharging circuit is formed; in the discharging circuit, the first capacitor (C01) is discharged through the seventh resistor (R08) provided in the connection circuit.

[0048] In this embodiment, according to the first capacitor, the third resistor, and the high and low level conversion threshold, the time when the inverting input terminal of the third amplifier reaches the same level as the non-inverting input terminal of the third amplifier in the charging circuit is determined to obtain the time of the charging circuit; according to the first capacitor, the seventh resistor, and the determined high and low level conversion threshold, the time when the non-inverting input terminal of the third amplifier reaches the same level as the inverting input terminal of the third amplifier in the discharging circuit is determined to obtain the time of the discharging circuit; specifically, the conversion time of the discharging circuit or the charging circuit is determined according to the following formula:

[0049] where, t L and t H are the time of the charging circuit and the time of the discharging circuit respectively; R3 and R7 are the above-mentioned third resistor and seventh resistor respectively; V 5_H and V 5_L are the above-mentioned high level conversion threshold and low level conversion threshold respectively; V3 is the sampling voltage; V D01 is the voltage of the diode (for reverse current protection); based on the above expression, the time of the charging circuit and the time of the discharging circuit are calculated, and thus the conversion time of the discharging circuit or the charging circuit is determined. According to the above formula for determining the conversion time of the discharging circuit or the charging circuit, it can be seen that the above-mentioned V 5_H , V 5_L , and V D01 are all stable values, and the time of the charging circuit changes with the change of the sampling voltage (i.e., V3) caused by temperature sensing by the temperature sensor, while the time of the discharging circuit remains unchanged.

[0050] Based on the above, a frequency signal is output according to the reciprocal of the sum of the time of the discharging circuit and the time of the charging circuit. That is f outThat is the output frequency signal. After the above frequency signal is output, it can also be sent to the MCU (Micro Control Unit) for data processing, and the obtained frequency signal is converted to obtain relevant test parameters.

[0051] For illustration, based on the above entire detection circuit, a diode-type temperature sensor is first adopted. Temperature change will cause the diode voltage drop to change, thereby affecting its sampling voltage. Through the above constant current source circuit, a stable current is input to the temperature sensor. The specific stable current input is as described above for I, forming a low-cost constant current source. Considering the influencing factors of the diode voltage drop including temperature and current, the input constant current source reduces the change in the diode voltage drop caused by current change, thereby avoiding the problem of inaccurate test accuracy caused by this current change in the subsequent sampling voltage. Then, the sampling circuit samples and amplifies the temperature sensor, that is, amplifies it to improve the sampling accuracy. Then, according to the sampling voltage output by the sampling circuit and the comparator flip threshold (that is, the high and low level conversion voltage conversion threshold of the above third amplifier), the sampling voltage is connected to the inverting input terminal of the third amplifier. When the inverting input terminal of the third amplifier with the input sampling voltage is at a low level relative to the non-inverting input terminal of the third amplifier, the first capacitor is charged through the third resistor to form a charging circuit; when the inverting input terminal of the third amplifier with the input sampling voltage is at a high level relative to the non-inverting input terminal of the third amplifier, the first capacitor is discharged through the seventh resistor to form a discharging circuit; until the non-inverting input terminal of the third amplifier reaches the same level as the inverting input terminal of the third amplifier for the conversion between the discharging circuit / charging circuit, and a frequency signal is output according to the conversion time of the circuit as the output of this detection circuit. Since the charging level (that is, the level of the inverting input terminal of the third amplifier corresponding to the above sampling voltage, which is related to the temperature sensor) is different, the time to charge to the same threshold (that is, the above low level conversion threshold) is different, resulting in the change of the output frequency signal. Based on this, the temperature test of the drive chip can be realized.

[0052] In this embodiment, based on the temperature sensor (diode type), the voltage drop changes due to temperature change, thereby causing the change of its sampling voltage. The change of the sampling voltage is reflected by the high and low level signal conversion time output by the third amplifier, and the change of the temperature sensor is determined through the output time / frequency signal, realizing the temperature detection of the module and solving the problem that the existing voltage-frequency conversion circuit for NTC temperature sensors cannot be applied to diode temperature sensors.

[0053] As a supplement, the detection circuit provided in this embodiment is also different from the detection circuit that may use a diode as a temperature sensor. It does not need to be placed inside the drive chip, which makes the drive chip internally built with complex circuits such as a constant current source circuit. Instead, it can operate independently of the drive chip and is connected to the drive chip of the lower bridge arm of the power module as described above (such as Figure 2In this case, the driver is a driving chip, and tsen1 and tsen2 correspond to the detection circuits in this embodiment. Generally, the driving module includes three power modules, thus including six driving chips. Each power module includes two driving chips, corresponding to the upper bridge arm and the lower bridge arm respectively. The detection circuit can be correspondingly connected to the driving chip of the lower bridge arm of each power module, so as to be applicable to the packaged power module, taking into account the cost advantage while improving the electric control power density.

[0054] It should be noted that the embodiments of the present invention have better implementability and are not any form of limitation to the present invention. Any person skilled in the art may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, as long as it does not depart from the technical content of the present invention, any modification, equivalent change or modification made to the above embodiments according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A semiconductor power module detection circuit, characterized in that: It includes a constant current source circuit, a sampling circuit and a frequency conversion circuit connected to a temperature sensor; wherein, the temperature sensor is a diode-type sensor; The constant current source circuit is connected to a first amplifier through a power supply voltage input terminal, so as to output a stable current to the temperature sensor; The sampling circuit processes the output of the temperature sensor through a second amplifier to obtain a sampling voltage; Under the frequency conversion circuit, the sampling voltage is input into a third amplifier, and according to the high and low level conversion voltage thresholds generated by the connection circuit on the third amplifier, a discharge circuit or a charging circuit is formed through a first capacitor connected to the third amplifier, and a frequency signal is output according to the conversion time of the discharge circuit or the charging circuit; When it is determined based on the sampling voltage and the high and low level conversion voltage thresholds that the inverting input terminal of the third amplifier inputting the sampling voltage is at a low level relative to the non-inverting input terminal of the third amplifier, a charging circuit is formed; When it is determined based on the sampling voltage and the high and low level conversion voltage thresholds that the inverting input terminal of the third amplifier inputting the sampling voltage is at a high level relative to the non-inverting input terminal of the third amplifier, a discharge circuit is formed; In the charging circuit, the first capacitor is charged through a third resistor connected in series between the second amplifier and the third amplifier; In the discharge circuit, the first capacitor is discharged through a seventh resistor provided in the connection circuit.

2. The detection circuit according to claim 1, characterized in that: The constant current source circuit includes a first resistor and a second resistor connected in parallel; The input terminal of the first resistor is connected to the power supply voltage input terminal, and the output terminal is connected to the second resistor and the first amplifier; The temperature sensor is connected in series with the first amplifier to input a stable current.

3. The detection circuit according to claim 1, characterized in that: In the sampling circuit, it is connected to the second amplifier through an adjustable resistor to sample and perform gain processing on the temperature sensor connected in series with the second amplifier, and the sampling voltage is obtained from the output terminal of the second amplifier.

4. The detection circuit according to claim 1, characterized in that: The connection circuit on the third amplifier includes a first control circuit for forming a charging circuit and a second control circuit for forming a discharge circuit; The first control circuit includes a fourth resistor, and a fifth resistor and a sixth resistor connected in series / parallel with the fourth resistor, The second control circuit includes a seventh resistor connected in series with the third amplifier and a diode for reverse current protection.

5. The detection circuit according to claim 4, characterized in that: In the first control circuit, the circuit formed by the parallel connection of the fourth resistor and the sixth resistor and then connected in series with the fifth resistor calculates the high level conversion voltage threshold for forming a discharge circuit based on the power supply voltage; the circuit formed by the parallel connection of the fourth resistor and the fifth resistor and then connected in series with the sixth resistor calculates the low level conversion threshold for forming a charging circuit based on the power supply voltage to obtain the high and low level conversion thresholds.

6. The detection circuit according to claim 1, characterized in that: Determine the time when the inverting input terminal of the third amplifier in the charging circuit reaches the same level as the non-inverting input terminal of the third amplifier according to the first capacitor, the third resistor, and the high and low level conversion threshold, and obtain the time of the charging circuit; Determine the time when the non-inverting input terminal of the third amplifier in the discharging circuit reaches the same level as the inverting input terminal of the third amplifier according to the first capacitor, the seventh resistor, and the determined high and low level conversion threshold, and obtain the time of the discharging circuit; Determine the conversion time of the discharging circuit or the charging circuit according to the time of the charging circuit and the time of the discharging circuit.

7. The detection circuit according to claim 6, wherein: Output a frequency signal according to the reciprocal of the sum of the time of the discharging circuit and the time of the charging circuit.

8. The detection circuit according to claim 6, wherein: The time of the charging circuit changes as the sampling voltage changes due to temperature caused by temperature sensing; The time of the discharging circuit remains unchanged.

9. The detection circuit according to claim 1, wherein: The detection circuit is connected to the power chip of the lower bridge arm in the semiconductor power module.

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