CN210221328U - Temperature detection module, temperature monitoring circuit and power chip - Google Patents
Temperature detection module, temperature monitoring circuit and power chip Download PDFInfo
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- CN210221328U CN210221328U CN201822274668.1U CN201822274668U CN210221328U CN 210221328 U CN210221328 U CN 210221328U CN 201822274668 U CN201822274668 U CN 201822274668U CN 210221328 U CN210221328 U CN 210221328U
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Abstract
The application discloses temperature detection module, temperature monitoring circuit and power chip. This temperature detection module includes: the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and at least one bipolar transistor connected in series, connected with the output end of the last stage current mirror in the at least two current mirrors, and the respective base collector electrodes are shorted to be connected in a diode mode, wherein a detection signal is provided at the output end of the last stage current mirror and is used for representing temperature information by the base emitter voltage of the at least one bipolar transistor. The temperature detection module adopts a bipolar transistor as a sensitive element, so that the temperature detection module can be integrated in a chip.
Description
Technical Field
The present invention relates to semiconductor technology, and more particularly, to a temperature detection module, a temperature monitoring circuit, and a power chip.
Background
Fig. 1 shows a schematic block diagram of a power chip according to the prior art. The package of the power chip 110 encapsulates the driving chips 111 to 113, the high-side switching transistor M11 and the low-side switching transistor M12 that constitute the first arm, the high-side switching transistor M21 and the low-side switching transistor M22 that constitute the second arm, the high-side switching transistor M31 and the low-side switching transistor M32 that constitute the third arm, and the thermistor RT.
The thermistor RT (divided into NTC and PTC resistors according to the temperature coefficient polarity) detects the chip temperature to realize the temperature monitoring function. For example, the PTC thermistor is connected to an external pull-up resistor via one pin of the power chip. The supply voltage VCC is provided to the pull-up resistor, thereby generating a bias current. The bias current flows through the thermistor PTC, thereby converting the temperature information into a detection signal. The higher the precision of the detection signal, the more accurate the temperature monitoring of the power chip.
In order to ensure that the value of the detection signal is within the allowable fluctuation range, for a power chip packaged with an NTC thermistor, the fluctuation level of the power supply voltage VCC and the precision requirement of the pull-up resistor during application need to be determined (when the fluctuation of the power supply voltage VCC is +/-1%, and the precision of the pull-up resistor is selected to be 1%, the fluctuation range of the detection signal is about +/-0.4V).
When a thermistor is used as a temperature sensor, a detection signal is affected by a power supply voltage VCC and a pull-up resistor, and the fluctuation range is large. The detection signal value is in a nonlinear relation with the temperature. For the NTC thermistor, when the temperature gradually decreases, the resistance of the thermistor increases, and at this time, the detection signal is closer to the power supply voltage VCC and gradually approaches saturation, and the nonlinearity rapidly increases. Because the resistance value of the thermistor and the temperature form a nonlinear relation, the batch dispersion is high, the detectable temperature range is small, and the reliable temperature monitoring of the power chip cannot be realized.
In addition, the thermistor is packaged inside the power chip, which itself requires additional die area, bonding wires, and additional pins for connecting the pull-up resistor, thus resulting in an increase in the size and application cost of the power chip. In the power chip, due to the limitation of safety distance and the like, the distance between the thermistor and a power device of the power chip is far, and accurate chip temperature cannot be provided.
Therefore, it is expected to adopt a novel temperature detection module instead of the thermistor to expand the linear range of the detection signal and improve the accuracy of temperature detection.
SUMMERY OF THE UTILITY MODEL
In view of this, the present invention provides a temperature detection module, a temperature monitoring circuit and a power chip, wherein the temperature detection module utilizes the base emitter voltage VBE of the bipolar transistor to represent temperature information, and adopts a compensation resistor to compensate the second-order temperature characteristic of the bipolar transistor, so as to expand the linear range of the detection signal.
According to the utility model discloses an aspect provides a temperature detection module, include: the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and at least one bipolar transistor connected in series, connected with the output end of the last stage current mirror in the at least two current mirrors, and the respective base collector electrodes are shorted to be connected in a diode mode, wherein a detection signal is provided at the output end of the last stage current mirror and is used for representing temperature information by the base emitter voltage of the at least one bipolar transistor.
Preferably, the amplification factor of the at least two current mirrors is set according to the second order temperature characteristic of the detection signal, thereby compensating for the second order temperature characteristic of the detection signal.
Preferably, the method further comprises the following steps: and a first resistor and a second resistor connected in series between a power supply terminal and an input terminal of the first stage current mirror so as to generate the reference current, wherein the first resistor and the second resistor have opposite temperature coefficients to obtain the reference current with a constant temperature coefficient.
Preferably, the method further comprises the following steps: and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
Preferably, the amplification of the at least two current mirrors is set according to the following formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of the first resistor, the second resistor, and the third resistor, respectively, k represents the number of the at least one bipolar transistor, and m × n represents an amplification factor of the at least two current mirrors, wherein the amplification factor of the at least two current mirrors, the resistance values of the first resistor, the second resistor, and the third resistor are set to compensate for a second term on the right side of the above equation, thereby realizing temperature compensation.
According to the utility model discloses a second aspect provides a temperature monitoring circuit, include: the temperature detection module is used for obtaining a detection signal; the operational amplifier, non-inverting input end and inverting input end receive reference signal and the detected signal respectively, and the output provides the error signal, wherein, temperature monitoring circuit produces the monitored signal according to the error signal, the temperature detection module includes: the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and at least one bipolar transistor connected in series, connected with the output end of the last stage current mirror of the at least two current mirrors, and the respective base collector electrodes are shorted to be connected in a diode mode, wherein a detection signal representing temperature information is provided at the output end of the last stage current mirror, and the detection signal represents the temperature information by using the base emitter voltage of the at least one bipolar transistor.
Preferably, the amplification factor of the at least two current mirrors is set according to the second order temperature characteristic of the detection signal, thereby compensating for the second order temperature characteristic of the detection signal.
Preferably, the method further comprises the following steps: and a first resistor and a second resistor connected in series between a power supply terminal and an input terminal of the first stage current mirror so as to generate the reference current, wherein the first resistor and the second resistor have opposite temperature coefficients to obtain the reference current with a constant temperature coefficient.
Preferably, the method further comprises the following steps: and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
Preferably, the amplification of the at least two current mirrors is selected according to the following formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of the first resistor, the second resistor, and the third resistor, respectively, k represents the number of the at least one bipolar transistor, and m × n represents an amplification factor of the at least two current mirrors, wherein the amplification factor of the at least two current mirrors, the resistance values of the first resistor, the second resistor, and the third resistor are set to compensate for a second term on the right side of the above equation, thereby achieving temperature compensation.
Preferably, the reference signal received by the operational amplifier is a reference signal obtained by compensating an input offset voltage of the operational amplifier.
Preferably, the monitoring device further comprises a driving module, wherein the driving module is connected with the operational amplifier so as to amplify the error signal into the monitoring signal.
Preferably, the driving module includes: the input end of the push-pull amplifier receives the error signal, and the output end of the push-pull amplifier provides the monitoring signal; and the low-resistance holding module is connected between the output end and a ground end, wherein the low-resistance holding module provides a low-resistance path to the ground when a transistor in the push-pull amplifier is in saturated conduction, so that linear output is maintained.
Preferably, the low resistance holding module includes at least two resistors of opposite temperature coefficients, or a pull-down constant current source, connected in series between the output terminal and a ground terminal.
Preferably, the push-pull amplifier includes: the first amplifying transistor, the fourth resistor, the fifth resistor and the second amplifying transistor are sequentially connected in series between a power supply end and a grounding end, wherein the first amplifying transistor and the second amplifying transistor are respectively bipolar transistors and of opposite types, the input end of the push-pull amplifier is connected to the intermediate node of the first amplifying transistor and the intermediate node of the second amplifying transistor, and the output end of the push-pull amplifier is connected to the intermediate node of the fourth resistor and the intermediate node of the fifth resistor.
Preferably, the method further comprises the following steps: the sixth resistor is connected between the inverting input end of the operational amplifier and the output end of the driving module; and the seventh resistor is connected between the inverting input end of the operational amplifier and the output end of the temperature detection module, wherein the sixth resistor and the seventh resistor form a feedback loop of the operational amplifier.
According to the utility model discloses a third aspect provides a power chip, includes: the high-side switch and the low-side switch are connected in series between a power supply end and a grounding end to form a bridge arm, and the middle node of the high-side switch and the low-side switch is connected to an output end; and a driving chip connected to the control terminal of the high-side switching tube and the control terminal of the low-side switching tube for providing a first switching control signal and a second switching control signal, wherein a temperature monitoring circuit is integrated in the driving chip, and the temperature monitoring circuit includes: the temperature detection module is used for obtaining a detection signal; the operational amplifier, non-inverting input end and inverting input end receive reference signal and the detected signal respectively, and the output provides the error signal, wherein, temperature monitoring circuit produces the monitored signal according to the error signal, the temperature detection module includes: the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and at least one bipolar transistor connected in series, connected with the output end of the last stage current mirror of the at least two current mirrors, and the respective base collector electrodes are shorted to be connected in a diode mode, wherein a detection signal representing temperature information is provided at the output end of the last stage current mirror, and the detection signal represents the temperature information by using the base emitter voltage of the at least one bipolar transistor.
Preferably, the amplification factor of the at least two current mirrors is set according to the second order temperature characteristic of the detection signal, thereby compensating for the second order temperature characteristic of the detection signal.
Preferably, the method further comprises the following steps: and a first resistor and a second resistor connected in series between a power supply terminal and an input terminal of the first stage current mirror so as to generate the reference current, wherein the first resistor and the second resistor have opposite temperature coefficients to obtain the reference current with a constant temperature coefficient.
Preferably, the method further comprises the following steps: and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
Preferably, the amplification of the at least two current mirrors is selected according to the following formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of a first resistor, a second resistor, and a third resistor, respectively, k represents the number of the at least one bipolar transistor, and m × n represents an amplification factor of the at least two current mirrors, where the amplification factor of the at least two current mirrors and the first resistor are setThe resistance values of the second resistor and the third resistor compensate for the second term on the right side of the above equation, thereby realizing that the temperature is compensated.
Preferably, the reference signal received by the operational amplifier is a reference signal obtained by compensating an input offset voltage of the operational amplifier.
Preferably, the monitoring device further comprises a driving module, wherein the driving module is connected with the operational amplifier so as to amplify the error signal into the monitoring signal.
Preferably, the driving module includes: the input end of the push-pull amplifier receives the error signal, and the output end of the push-pull amplifier provides the monitoring signal; and the low-resistance holding module is connected between the output end and a ground end, wherein the low-resistance holding module provides a low-resistance path to the ground when a transistor in the push-pull amplifier is in saturated conduction, so that linear output is maintained.
Preferably, the low resistance holding module includes at least two resistors of opposite temperature coefficients, or a pull-down constant current source, connected in series between the output terminal and a ground terminal.
Preferably, the push-pull amplifier includes: the first amplifying transistor, the fourth resistor, the fifth resistor and the second amplifying transistor are sequentially connected in series between a power supply end and a grounding end, wherein the first amplifying transistor and the second amplifying transistor are respectively bipolar transistors and of opposite types, the input end of the push-pull amplifier is connected to the intermediate node of the first amplifying transistor and the intermediate node of the second amplifying transistor, and the output end of the push-pull amplifier is connected to the intermediate node of the fourth resistor and the intermediate node of the fifth resistor.
Preferably, the method further comprises the following steps: the sixth resistor is connected between the inverting input end of the operational amplifier and the output end of the driving module; and the seventh resistor is connected between the inverting input end of the operational amplifier and the output end of the temperature detection module, wherein the sixth resistor and the seventh resistor form a feedback loop of the operational amplifier.
In the temperature monitoring circuit of this embodiment, the temperature detection module uses the base-emitter voltage VBE of the bipolar transistor to characterize the temperature information. Because the bipolar transistor is used as a sensitive element, the temperature detection module can be integrated in a chip. Each module of the temperature monitoring circuit can be realized by adopting a universal BCD process. The BCD process is a monolithic IC fabrication process that combines bipolar and CMOS processes. Therefore, a temperature monitoring circuit can be integrated in the driving chip of the power chip, and the temperature sensitive resistor is omitted. The temperature monitoring circuit integrated inside the chip improves the accuracy of temperature measurement.
In a preferred embodiment, the temperature detection module sets the amplification factor of the current mirror according to the second-order temperature characteristic of the detection signal, so that the second-order temperature characteristic of the detection signal is compensated, and the linear range of the high-temperature region can be expanded. The temperature detection module may further include a low resistance holding module providing a low resistance path to ground when the transistor in the push-pull amplifier is in saturation conduction, thereby maintaining a linear output of the monitoring signal and thus expanding a linear range of the low temperature region. According to the utility model discloses temperature monitoring module has all enlarged linear range in high low temperature district, therefore can enlarge the detection range of temperature.
In the existing power chip, the thermistor and the driving chip are independent elements, and are connected by a bonding wire and then packaged in the same package. Different from the prior art, according to the utility model discloses temperature monitoring module integration is inside driver chip to can save the bonding connection of encapsulation stage, and save power chip's additional pin and peripheral component.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 shows a schematic block diagram of a power chip according to the prior art.
Fig. 2 shows a schematic block diagram of a temperature monitoring circuit according to an embodiment of the invention.
FIG. 3 is a graph showing the temperature dependence of the detection signal of the temperature monitoring circuit of FIG. 1.
Fig. 4 shows a schematic circuit diagram of a temperature detection module of the temperature monitoring circuit of fig. 1.
Fig. 5 shows a schematic circuit diagram of a drive module of the temperature monitoring circuit of fig. 1.
Fig. 6 shows a schematic block diagram of a power chip according to an embodiment of the present invention.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The present invention will be further explained with reference to the drawings and examples.
Fig. 2 shows a schematic block diagram of a temperature monitoring circuit according to an embodiment of the invention.
The temperature monitoring circuit 100 includes a temperature detection module 110, an operational amplifier 120, a driving module 130, and resistors R0 and R1.
The temperature sensing module 110 uses the base-emitter voltage VBE of the bipolar transistor to characterize the temperature information, thereby generating the sensing signal Vt. The operational amplifier 120 has a non-inverting input receiving the reference signal Vref and an inverting input receiving the detection signal Vt, respectively, and an output providing the error signal Va. The reference signal Vref is an internal reference voltage, ideally with a zero temperature coefficient (over a wide temperature range rather than at a certain temperature point). Since the operational amplifier 120 does not have an output driving capability, the driving module 130 serves as an output buffer stage for amplifying the error signal Va to the monitor signal Vtm, thereby improving the driving capability of the port and providing the electrostatic protection characteristic.
The resistors R0 and R1 form a feedback loop, and the resistor types of the resistors R0 and R1 are consistent to satisfy the matching principle. The resistor R0 is connected between the inverting input terminal of the operational amplifier 120 and the output terminal of the driving module 130, and the resistor R1 is connected between the inverting input terminal of the operational amplifier 120 and the output terminal of the temperature detecting module 110. The feedback loop feeds back the monitoring signal Vtm to the inverting input of the operational amplifier 120.
In the temperature monitoring circuit 100 of this embodiment, the temperature detection module 110 uses the base-emitter voltage VBE of the bipolar transistor to represent temperature information, and compensates for the second-order temperature characteristic, so that the linear range of the detection signal can be expanded.
Further, each module of the temperature monitoring circuit 100 can be implemented by using a general BCD process. The BCD process is a monolithic IC fabrication process that combines bipolar and CMOS processes, and can produce bipolar transistors and MOS field effect transistors on a wafer. Therefore, the temperature monitoring circuit 100 and the MCU (microcontroller) can be integrated at the same time in the power chip.
In the existing power chip, a thermistor and an MCU are independent elements, connected by a bonding wire, and then packaged in the same package. Different from the prior art, according to the utility model discloses temperature monitoring module and MCU then can be integrated into single chip to can save the bonding connection of encapsulation stage, and save power chip's additional pin and peripheral component.
FIG. 3 is a graph showing the temperature dependence of the detection signal of the temperature monitoring circuit of FIG. 1.
In the temperature monitoring circuit 100 according to the embodiment of the present invention, the temperature detecting module 110 obtains the detecting signal Vt representing the temperature information, the operational amplifier 120 compares the detecting signal Vt with the reference signal Vref to generate the error signal Va, and the driving module 130 amplifies the error signal Va into the monitoring signal Vtm.
The signal relationship of the temperature monitoring circuit 100 can be derived from the following equation:
where Vt represents a detection signal at the inverting input terminal of the operational amplifier, Vtm0 represents an initial detection signal obtained by the temperature detection module, Vref0 represents an initial reference signal, Vos represents an input offset voltage of the operational amplifier 120, R0 represents a value of the resistor R0, and R1 represents a value of the resistor R1.
Therefore, the method has the advantages that in the method,
therefore, as can be seen from equation 2, the initial sensing signal Vtm0 is composed of two parts, i.e., the initial reference signal Vref0 at the non-inverting input terminal, and the sensing signal Vt at the inverting input terminal of the operational amplifier.
The utility model discloses in, owing to need obtain the monitor signal of high accuracy, designed the trimming mode of compensation input offset voltage Vos, thereby it offsets input offset voltage Vos to go to in the equivalent reference signal Vref of input offset voltage Vos soon. Therefore, the monitoring signal Vtm can be further expressed as:
where Vref denotes a reference signal obtained by compensating the input offset voltage Vos in the initial reference signal Vref 0.
If the temperature characteristic of the proportional resistor is neglected, the temperature coefficient k of the monitoring signal Vtm can be obtainedTExpression:
the utility model discloses in the temperature monitoring circuit, the temperature coefficient design of reference signal Vref is the zero temperature characteristic in the wide range, and the detected signal Vt is the negative temperature coefficient to realize the voltage output of a positive temperature coefficient's control signal Vtm along with the linear change of temperature. Compared with the packaging thermistor (NTC/PTC) mode, the temperature-voltage characteristic improvement that the embodiment of the utility model obtains is obvious.
In the low temperature region, Vtm ≧ Vref, current paths for the detection signal Vt and the monitor signal Vtm to ground will occur, which may cause nonlinearity of the monitor signal Vtm if the ground path design of the driving module 130 is not reasonable.
Referring to fig. 3, curves Ls1 and Ls2 respectively show the output characteristics of the temperature monitoring circuit of the prior art, the temperature range of the linear output is small, and the linear output enters a non-linear region at high and low temperatures. Curve La represents the output characteristic of the temperature monitoring circuit according to an embodiment of the present invention. The linear range of the monitoring signal Vtm is close to-40 ℃ to 150 ℃, and the output saturation voltage V0 in the low-temperature region is approximately equal to 0.
Therefore, according to the utility model discloses temperature monitoring module has all enlarged linear range in high low temperature district.
Fig. 4 shows a schematic circuit diagram of a temperature detection module of the temperature monitoring circuit of fig. 1.
The temperature sensing module 110 includes at least two cascaded current mirrors. For example, the temperature sensing module includes NMOS transistors N0 and N1 constituting a first current mirror, and PMOS transistors P0 and P1 constituting a second current mirror. The width-to-length ratio of the NMOS transistors N0 and N1 is 1: m, PMOS transistors P0 and P1 are 1: n is the same as the formula (I).
The resistors R10 and R11 are resistors with opposite temperature characteristics, and are connected in series with the NMOS transistor N0 between the power supply terminal VREG and the ground terminal GND, so as to generate the reference current Iref with a constant temperature coefficient, thereby realizing temperature compensation. The reference current is coupled through the first current mirror and the second current mirror as a driving current Io n m Iref.
Further, a PMOS transistor P1, k bipolar transistors Q10, and a resistor R12 are connected in series between the power supply terminal VREG and the ground terminal GND in this order. The bipolar transistors Q10 are each connected as a diode, i.e., a base-collector short. The voltage drop generated at each bipolar transistor Q10 is the base-emitter voltage VBE. This embodiment uses the base-emitter voltage VBE of k bipolar transistors Q10, where k is an integer greater than or equal to 1, to characterize the temperature information.
From the above schematic circuit diagram, an expression of the detection signal Vt can be given:
wherein Vt represents a detection signal obtained by the temperature detection module, VBE represents a base emitter voltage of the bipolar transistor Q10, VREG represents a supply voltage, VGS represents a source-drain voltage of the PMOS transistor P1, R10, R11, and R12 each represent a resistance value of a corresponding resistor in the figure, k represents the number of the bipolar transistors Q10, and m and n each represent a current amplification factor of the first current mirror and the second current mirror.
According to the foregoing, the resistors R10 and R11 have a certain temperature compensation effect, and the second term on the right side of equation 5 is a second-order term of the temperature characteristic, so that the second-order temperature characteristic of VBE can be effectively compensated. Therefore, the size ratios m and n of the NMOS/PMOS transistors and the resistors R10, R11, R12 can be adjusted to realize the negative temperature characteristic linearization of the sense signal Vt, i.e., the negative temperature characteristic linearization
Where C represents the first order temperature coefficient (i.e., constant) of the base emitter voltage VBE of bipolar transistor Q10.
As can be seen from equation 6, the temperature detection module 110 characterizes temperature information using the base-emitter voltage VBE of the bipolar transistor and compensates for the second-order temperature characteristic, so that the linear range of the detection signal can be expanded in a high temperature region.
Fig. 5 shows a schematic circuit diagram of a drive module of the temperature monitoring circuit of fig. 1.
The operational amplifier 120 and the driving module 130 in the temperature monitoring circuit 100 perform signal processing on the detection signal Vt obtained by the temperature detection module 110 to obtain the monitoring signal Vtm.
The driver module 130 includes bipolar transistors Q20 and Q21 of opposite type, resistors R20 and R21.
The bipolar transistor Q20, the resistors R20 and R21, and the bipolar transistor Q21 are sequentially connected in series between the power supply terminal VCC and the ground terminal GND, thereby constituting the push-pull amplifier 131. The load charging and discharging current of the push-pull amplifier 131 depends on the emitter areas of the bipolar transistors Q0 and Q1. The bases of bipolar transistors Q20 and Q21 are commonly connected to the input to receive the error signal Va. The intermediate node of resistors R20 and R21 is connected to the output terminal to provide the monitor signal Vtm. The resistors R20 and R21 are used for improving the electrostatic protection capability of the output port.
On the basis of the above equation 6, the temperature system k of the monitoring signal Vtm can be further obtainedTIs shown as
Where k denotes the number of bipolar transistors Q10 in the temperature detection module 110, and C denotes a first-order temperature coefficient (i.e., constant) of the base-emitter voltage VBE of the bipolar transistor Q10.
As can be seen from equation 7, the temperature detection block 110 in the temperature monitoring circuit 100 represents temperature information using the base-emitter voltage VBE of the bipolar transistor and compensates for the second-order temperature characteristic, so that the linear range of the detection signal can be expanded in a high temperature region. Therefore, the monitor signal Vtm also expands the linear range of the detection signal accordingly.
In a preferred embodiment, the drive module 130 may include an additional low resistance holding module 132. The low resistance holding module 132 is, for example, two resistors with opposite temperature coefficients connected in series between the output terminal and the ground terminal, or a pull-down constant current source.
In the middle and high temperature region, the error signal Va at the input of the push-pull amplifier 131 is higher, and the bipolar transistor Q21 is linearly turned on. The monitor signal Vtm is correlated with the sense signal Vt, and thus temperature information is represented by the sense signal Vt.
In the low temperature region, the error signal Va at the input terminal of the push-pull amplifier 131 is close to the low level, and the bipolar transistor Q21 is in saturation conduction. The low resistance hold block 132 provides a low resistance path to ground when the transistors in the push-pull amplifier are conducting in saturation, thereby maintaining a linear output of the monitor signal Vtm.
The driving module 130 of the preferred embodiment can ensure that the monitoring signal Vtm keeps changing linearly even when the bipolar transistor in the low-temperature push-pull amplifier 131 is turned on in saturation, so as to effectively improve the problem of non-linearity of the output of the monitoring signal Vtm in the low-temperature region.
Fig. 6 shows a schematic block diagram of a power chip according to an embodiment of the present invention. The driver chips 211 to 213, the high-side switch transistor M21 and the low-side switch transistor M12 forming the first leg, the high-side switch transistor M21 and the low-side switch transistor M22 forming the second leg, and the high-side switch transistor M31 and the low-side switch transistor M32 forming the third leg are encapsulated in the package of the power chip 210.
The driver chip 211 is connected to the control terminal M11 of the high-side switch and the control terminal of the low-side switch M12, and provides corresponding switch control signals, respectively. The driver chip 212 is connected to the control terminal M21 of the high-side switch and the control terminal of the low-side switch M22, and provides corresponding switch control signals. The driver chip 213 is connected to the control terminal M31 of the high-side switch and the control terminal of the low-side switch M32, and provides corresponding switch control signals.
Further, the temperature monitoring circuit 100 shown in fig. 2 is integrated in the driving chip 211. Since the driver chips 211 to 213, the high-side switch M21 and the low-side switch M12 constituting the first bridge arm, the high-side switch M21 and the low-side switch M22 constituting the second bridge arm, and the high-side switch M31 and the low-side switch M32 constituting the third bridge arm are sealed in the package of the power chip 210, when the Temperature of the power chip 210 rises, the Temperature of the driver chip 211 also rises, and the Temperature detection circuit (Temperature Sensor)110 integrated therein converts the Temperature signal into a linear voltage signal VTH.
In practical products (such as a mobile power supply or a charger), the power chip 210 is connected to a Microcontroller (MCU)220, and directly transmits the voltage signal VTH to the MCU to monitor the temperature of the smart power module in real time.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In accordance with the embodiments of the present invention as set forth above, these embodiments are not exhaustive and do not limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The present invention is limited only by the claims and their full scope and equivalents.
Claims (27)
1. A temperature sensing module, comprising:
the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and
at least one bipolar transistor connected in series, connected to an output terminal of a final-stage current mirror of the at least two current mirrors, and having respective base collectors shorted to be connected in a diode form,
and providing a detection signal at the output end of the final stage current mirror, wherein the detection signal adopts the base emitter voltage of the at least one bipolar transistor to represent temperature information.
2. The temperature sensing module of claim 1, wherein the amplification of the at least two current mirrors is set according to a second order temperature characteristic of the sensing signal, thereby compensating for the second order temperature characteristic of the sensing signal.
3. The temperature sensing module of claim 2, further comprising:
a first resistor and a second resistor connected in series between a supply terminal and an input terminal of the first-stage current mirror to generate the reference current,
wherein the temperature coefficients of the first resistor and the second resistor are opposite to obtain a reference current with a constant temperature coefficient.
4. The temperature sensing module of claim 3, further comprising:
and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
5. The temperature sensing module of claim 4, wherein the amplification of the at least two current mirrors is set according to the following formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of the first resistor, the second resistor, and the third resistor, respectively, k represents the number of the at least one bipolar transistor, m × n represents an amplification factor of the at least two current mirrors,
wherein the amplification factor of the at least two current mirrors, and the resistance values of the first resistor, the second resistor, and the third resistor are set to compensate for the equation
Second term on right side, thereby realizing temperatureAnd (5) degree compensation.
6. A temperature monitoring circuit, comprising:
the temperature detection module is used for obtaining a detection signal;
an operational amplifier having a non-inverting input terminal and an inverting input terminal for receiving the reference signal and the detection signal, respectively, an output terminal for providing an error signal,
wherein the temperature monitoring circuit generates a monitoring signal based on the error signal,
the temperature detection module includes:
the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and
at least one bipolar transistor connected in series, connected to an output terminal of a final-stage current mirror of the at least two current mirrors, and having respective base collectors shorted to be connected in a diode form,
and providing a detection signal representing temperature information at the output end of the final stage current mirror, wherein the detection signal represents the temperature information by adopting the base emitter voltage of the at least one bipolar transistor.
7. The temperature monitoring circuit of claim 6, wherein the amplification of the at least two current mirrors is set according to a second order temperature characteristic of the detection signal, thereby compensating for the second order temperature characteristic of the detection signal.
8. The temperature monitoring circuit of claim 7, further comprising:
a first resistor and a second resistor connected in series between a supply terminal and an input terminal of the first-stage current mirror to generate the reference current,
wherein the temperature coefficients of the first resistor and the second resistor are opposite to obtain a reference current with a constant temperature coefficient.
9. The temperature monitoring circuit of claim 8, further comprising:
and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
10. The temperature monitoring circuit of claim 9, wherein the amplification of the at least two current mirrors is selected according to the formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of the first resistor, the second resistor, and the third resistor, respectively, k represents the number of the at least one bipolar transistor, m × n represents an amplification factor of the at least two current mirrors,
wherein the amplification factor of the at least two current mirrors, and the resistance values of the first resistor, the second resistor, and the third resistor are set to compensate for the equation
The second term on the right, thereby achieving that the temperature is compensated.
11. The temperature monitoring circuit of claim 6, wherein the reference signal received by the operational amplifier is a reference signal obtained by compensating an input offset voltage of the operational amplifier.
12. The temperature monitoring circuit according to any one of claims 6 to 11, further comprising a driving module connected to the operational amplifier to amplify the error signal into the monitoring signal.
13. The temperature monitoring circuit of claim 12, wherein the driver module comprises:
the input end of the push-pull amplifier receives the error signal, and the output end of the push-pull amplifier provides the monitoring signal; and
a low resistance holding module connected between the output terminal and a ground terminal,
wherein the low resistance holding module provides a low resistance path to ground when a transistor in the push-pull amplifier is in saturation conduction, thereby maintaining a linear output.
14. The temperature monitoring circuit of claim 13, wherein the low resistance holding module comprises at least two resistors of opposite temperature coefficients connected in series between the output terminal and ground, or a pull-down constant current source.
15. The temperature monitoring circuit of claim 13, wherein the push-pull amplifier comprises:
a first amplifying transistor, a fourth resistor, a fifth resistor, and a second amplifying transistor connected in series in sequence between the power supply terminal and the ground terminal,
the first amplifying transistor and the second amplifying transistor are bipolar transistors and are opposite in type, the input end of the push-pull amplifier is connected to the middle node of the first amplifying transistor and the middle node of the second amplifying transistor, and the output end of the push-pull amplifier is connected to the middle node of the fourth resistor and the middle node of the fifth resistor.
16. The temperature monitoring circuit of claim 12, further comprising:
the sixth resistor is connected between the inverting input end of the operational amplifier and the output end of the driving module; and
a seventh resistor connected between the inverting input terminal of the operational amplifier and the output terminal of the temperature detection module,
wherein the sixth resistor and the seventh resistor form a feedback loop of the operational amplifier.
17. A power chip, comprising:
the high-side switch and the low-side switch are connected in series between a power supply end and a grounding end to form a bridge arm, and the middle node of the high-side switch and the low-side switch is connected to an output end; and
a driving chip connected to the control terminal of the high-side switching tube and the control terminal of the low-side switching tube for providing a first switching control signal and a second switching control signal respectively,
wherein, the drive chip is integrated with a temperature monitoring circuit, and the temperature monitoring circuit comprises:
the temperature detection module is used for obtaining a detection signal;
an operational amplifier having a non-inverting input terminal and an inverting input terminal for receiving the reference signal and the detection signal, respectively, an output terminal for providing an error signal,
wherein the temperature monitoring circuit generates a monitoring signal based on the error signal,
the temperature detection module includes:
the current source circuit comprises at least two cascaded current mirrors, wherein a first stage current mirror of the at least two current mirrors receives a reference current, and a last stage current mirror provides a driving current which is amplified by the reference current; and
at least one bipolar transistor connected in series, connected to an output terminal of a final-stage current mirror of the at least two current mirrors, and having respective base collectors shorted to be connected in a diode form,
and providing a detection signal representing temperature information at the output end of the final stage current mirror, wherein the detection signal represents the temperature information by adopting the base emitter voltage of the at least one bipolar transistor.
18. The power chip of claim 17, wherein the amplification of the at least two current mirrors is set according to a second order temperature characteristic of the detection signal, thereby compensating for the second order temperature characteristic of the detection signal.
19. The power chip of claim 18, further comprising:
a first resistor and a second resistor connected in series between a supply terminal and an input terminal of the first-stage current mirror to generate the reference current,
wherein the temperature coefficients of the first resistor and the second resistor are opposite to obtain a reference current with a constant temperature coefficient.
20. The power chip of claim 19, further comprising:
and a third resistor connected in series with the at least one bipolar transistor between the output terminal of the final stage current mirror and a ground terminal.
21. The power chip of claim 20, wherein the amplification of the at least two current mirrors is selected according to the following formula,
wherein Vt represents a detection signal of the temperature detection module, VBE represents a base emitter voltage of the at least one bipolar transistor, VREG represents a supply voltage, VGS represents a source-drain voltage of a transistor of the at least two current mirrors, R10, R11, and R12 represent resistance values of the first resistor, the second resistor, and the third resistor, respectively, k represents the number of the at least one bipolar transistor, m × n represents an amplification factor of the at least two current mirrors,
wherein the amplification factor, the first resistor, the second resistor and the third resistor of the at least two current mirrors are setTo compensate for said equation
The second term on the right, thereby achieving that the temperature is compensated.
22. The power chip of claim 17, wherein the reference signal received by the operational amplifier is a reference signal obtained by compensating an input offset voltage of the operational amplifier.
23. The power chip of any one of claims 17 to 22, further comprising a driving module connected to the operational amplifier to amplify the error signal into the monitor signal.
24. The power chip of claim 23, wherein the driving module comprises:
the input end of the push-pull amplifier receives the error signal, and the output end of the push-pull amplifier provides the monitoring signal; and
a low resistance holding module connected between the output terminal and a ground terminal,
wherein the low resistance holding module provides a low resistance path to ground when a transistor in the push-pull amplifier is in saturation conduction, thereby maintaining a linear output.
25. The power chip of claim 24, wherein the low resistance holding module comprises at least two resistors of opposite temperature coefficients connected in series between the output terminal and a ground terminal, or a pull-down constant current source.
26. The power chip of claim 24, wherein the push-pull amplifier comprises:
a first amplifying transistor, a fourth resistor, a fifth resistor, and a second amplifying transistor connected in series in sequence between the power supply terminal and the ground terminal,
the first amplifying transistor and the second amplifying transistor are bipolar transistors and are opposite in type, the input end of the push-pull amplifier is connected to the middle node of the first amplifying transistor and the middle node of the second amplifying transistor, and the output end of the push-pull amplifier is connected to the middle node of the fourth resistor and the middle node of the fifth resistor.
27. The power chip of claim 23, further comprising:
the sixth resistor is connected between the inverting input end of the operational amplifier and the output end of the driving module; and
a seventh resistor connected between the inverting input terminal of the operational amplifier and the output terminal of the temperature detection module,
wherein the sixth resistor and the seventh resistor form a feedback loop of the operational amplifier.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109764972A (en) * | 2018-12-29 | 2019-05-17 | 杭州士兰微电子股份有限公司 | Temperature detecting module, temperature monitoring circuit and power chip |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109764972A (en) * | 2018-12-29 | 2019-05-17 | 杭州士兰微电子股份有限公司 | Temperature detecting module, temperature monitoring circuit and power chip |
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