Power tube temperature detection device
By using copper wire connection and temperature detection circuit between the driver controller chip and the power transistor chip, the problems of high design difficulty and low accuracy of power transistor temperature detection in the prior art are solved, realizing fast and accurate temperature protection and reducing design complexity and cost.
Patent Information
- Application Number
- CN202423096529.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-12-16
AI Technical Summary
Existing power transistor temperature detection methods suffer from high design difficulty, increased cost, and low detection accuracy, especially in high-current applications, where it is difficult to achieve fast and accurate temperature protection.
The source terminals of the driver controller chip and the power transistor chip are connected by copper wire. The temperature of the power transistor is detected in real time through a temperature detection circuit. The negative temperature characteristic of the temperature sampling diode and the comparator are used to achieve fast and accurate temperature detection, reducing design complexity and cost.
It enables rapid and accurate temperature detection of power transistors under high current applications, improving the reliability and response speed of temperature protection, and reducing design difficulty and cost.
Smart Images
Figure CN223500521U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to power stage chips, specifically to a power transistor temperature detection device. Background Technology
[0002] Intelligent power stage chips, such as driver power transistor chips and motor driver chips, generally consist of two parts: a driver controller and a power transistor. In high-current applications, the power transistor typically needs to provide 50A to 100A of current, and its on-resistance R... DS(on) The requirement is to keep the resistance within 1mΩ. This is difficult to achieve optimal performance using common manufacturing processes for drive controllers, so discrete components are generally used: the on-resistance R is adjusted by modifying the power transistor's process. DS(on) The optimal driving loss is achieved, while the analog driving circuit adopts a general process design so that the two do not affect each other.
[0003] For such high-current, high-reliability applications, temperature protection is required for the high-current path, i.e., the power transistor, to prevent overheating and damage to the power transistor, which could further lead to the burnout of subsequent circuits.
[0004] In the existing technology, there are two main methods for sampling the temperature of power transistors:
[0005] Figure 1 This is a schematic diagram of a device for detecting the temperature of a power transistor in the prior art. Figure 1 As shown, a temperature sampling circuit A1 is integrated on the power transistor chip A to sample and monitor the temperature of the power transistor and transmit this sampled signal to the drive control chip B. A temperature protection circuit B1 is provided on the drive control chip B to receive the temperature signal transmitted by the temperature sampling circuit A1. A bonding wire C connects the temperature sampling circuit A1 and the temperature protection circuit B1.
[0006] Temperature sampling circuit A1 uses a diode to sample the temperature of the power transistor. Because the diode's voltage drop has a negative temperature characteristic, when the temperature of power transistor chip A is too high, temperature protection circuit B1 receives the changing voltage signal and drives control chip B to shut down the power transistor. The bonding wire C is used to transmit the voltage signal.
[0007] Because the temperature sampling circuit A1 is located inside the power transistor chip A, it can synchronously detect the temperature of the power transistor. The control chip B can then instantly issue a protection action by detecting the voltage signal. However, this method requires the temperature sampling circuit A1 to be integrated inside the power transistor chip A. This not only increases the design complexity of the power transistor chip A, but also, because the temperature sampling circuit A1 occupies a portion of the area of the power transistor chip A, it increases the on-resistance R of the power transistor chip A for the same area. DS(on)The size increases. In addition, most commercially available general-purpose power transistor chips A do not have temperature detection functionality. If this function is required, the power transistor chip A must be redesigned, which greatly increases the design cost and time.
[0008] Figure 2 This is a schematic diagram of another device for controlling the temperature of a power transistor in the prior art. For example... Figure 2 As shown, a first temperature monitoring circuit B1 and a second temperature monitoring circuit B2 are set in the drive control chip B to detect the internal temperature gradient change of the drive control chip B. By detecting this temperature difference, the temperature difference between the power transistor chip A and the drive control chip B is simulated, thereby achieving the purpose of protecting the power transistor.
[0009] However, after chip packaging, the power transistor chip A and the drive control chip B are surrounded by encapsulating epoxy resin. When a large current flows through the power transistor chip A and its temperature rises, the temperature is conducted to the drive control chip B through the epoxy resin. At this time, the temperature difference between the power transistor chip A and the first temperature monitoring circuit B1 can be used to simulate the temperature difference between the power transistor chip A and the first temperature monitoring circuit B1, thereby realizing the temperature protection function of the power transistor chip A. This method obviously does not require the power transistor chip A to integrate a temperature detection unit, reducing the design difficulty and cost of the power transistor; however, since the distance between the power transistor chip A and the drive control chip B cannot be precisely determined, and the temperature conduction is not completely linear, the accuracy of this detection method is not high. On the other hand, the thermal conductivity of the chip encapsulating epoxy resin is 0.2~0.4W / m*K, which means that for 1W of power, a distance of 1cm, and a unit time of 1s, the temperature transferred is 20~40K. This means that when the power transistor chip A suddenly draws in a large current and its temperature rises rapidly, it takes about 4 to 5 seconds for the controller to detect the temperature and activate the protection. This could lead to the power transistor chip A overheating and being damaged before the control signal issues the protection action. Therefore, this temperature detection method has a relatively large delay. Utility Model Content
[0010] To address the shortcomings of existing technologies, this utility model discloses a power transistor temperature detection device.
[0011] The technical solution adopted in this utility model is as follows:
[0012] A power transistor temperature detection device is provided for detecting the temperature of a power transistor in a power stage chip. The power stage chip includes a driver controller chip and a power transistor chip. The driver controller chip generates a control signal. The power transistor chip includes a power transistor. The power transistor receives the control signal and turns on or off according to the control signal. The power transistor temperature detection device includes: a first pad disposed on the driver controller chip; a second pad disposed on the source of the power transistor on the power transistor chip; a wire bond, with its two ends soldered to the first pad and the second pad respectively; and a temperature detection circuit disposed on the driver controller chip for detecting the temperature of the first pad and outputting a temperature detection signal to the driver controller chip.
[0013] The further technical solution is that the wire is made of copper wire.
[0014] A further technical solution is that the temperature detection circuit is located below or beside the first pad.
[0015] A further technical solution is as follows: multiple first pads are provided; multiple bonding wires are provided, and the number corresponds to the number of first pads; the first ends of the multiple bonding wires are soldered to the multiple first pads one by one; the second ends of the bonding wires are all soldered to the second pads; the second ends of the bonding wires are soldered to different positions of the second pads.
[0016] The further technical solution is that the length of the bonding wire is 0.3mm to 0.5mm.
[0017] The further technical solution is as follows: the power transistor is a discrete device and is a vertical power transistor; a source electrode is provided at the top of the power transistor, and the first pad is provided at the source electrode at the top of the power transistor chip.
[0018] A further technical solution is as follows: the temperature detection circuit includes: a temperature sampling diode, the forward voltage drop of which has a negative temperature characteristic; a DC current source for driving the temperature sampling diode; a reference voltage source for providing a reference voltage; a comparator, the positive input terminal of which receives the reference voltage, the inverting input terminal of which receives the forward voltage of the temperature sampling diode, and the comparator outputting a temperature detection signal.
[0019] A further technical solution is as follows: the drive controller chip includes a drive control circuit, the drive control circuit includes: a logic OR circuit, the first input terminal of the logic OR circuit is used to receive a PWM signal; the second input terminal of the logic OR circuit is used to receive a protection signal; the protection signal includes a temperature detection signal; the logic OR circuit outputs a first drive signal; the control signal turns off the power transistor according to the first drive signal.
[0020] A further technical solution is as follows: the drive control circuit further includes: an upper drive circuit, which receives the first drive signal, amplifies it, and outputs a second drive signal; a lower drive circuit, which receives the first drive signal, amplifies it, and outputs a third drive signal; an upper drive transistor, the first end of which is connected to a power supply voltage, and the gate of which receives the second drive signal; a lower drive transistor, the type of which is opposite to that of the upper drive transistor; the first end of which is connected to a ground terminal, the second end of which is connected to the second end of the upper drive transistor, and the gate of which receives the third drive signal; wherein, the common terminal of the upper drive transistor and the lower drive transistor outputs a control signal for controlling the power transistor to be turned on or off.
[0021] The beneficial effects of this utility model are as follows:
[0022] The temperature detection device in this invention achieves temperature transfer through wire bonding. On the one hand, it is compatible with existing power transistor designs, eliminating the need for costly redesign of the power transistor chip. On the other hand, compared with the temperature gradient detection scheme in existing designs, it can detect the temperature of the power transistor more accurately and quickly, providing higher reliability. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of a power transistor temperature detection device in the prior art.
[0024] Figure 2 This is a schematic diagram of another implementation of a power transistor temperature detection device in the prior art.
[0025] Figure 3 This is a schematic diagram of the power tube temperature detection device in an embodiment of this utility model.
[0026] Figure 4 This is a schematic diagram of the structural layout of the top of the vertical power transistor in an embodiment of this utility model.
[0027] Figure 5 This is a schematic diagram of another embodiment of the power tube temperature detection device in this utility model.
[0028] Figure 6 This is a schematic diagram of the temperature detection circuit in an embodiment of the present invention.
[0029] Figure 7 This is a schematic diagram of the drive control circuit in an embodiment of the present invention. Detailed Implementation
[0030] The specific embodiments of this utility model are described below with reference to the accompanying drawings.
[0031] Figure 3 This is a schematic diagram of the power tube temperature detection device in an embodiment of this utility model. Figure 3 As shown, this embodiment discloses a power transistor temperature detection device for detecting the temperature of the power transistor in a power stage chip. The power stage chip includes a driver controller chip B and a power transistor chip A. The driver controller chip B is used to generate control signals. The power transistor chip A includes a power transistor. The power transistor is used to receive the control signals and turn on or off according to the control signals.
[0032] The power transistor temperature detection device includes a temperature detection circuit B1, a first pad PAD1, a second pad PAD2, and a wire bond C. The first pad PAD1 is located on the driver controller chip B. The second pad PAD2 is located at the source of the power transistor on the power transistor chip A. The two ends of the wire bond C are soldered to the first pad PAD1 and the second pad PAD2, respectively. The temperature detection circuit B1, located on the driver controller chip B, is used to detect the temperature of the first pad PAD1 and output a temperature detection signal to the driver controller chip B.
[0033] The first pad PAD1 and the second pad PAD2 are interconnected via wire bonding C to transfer temperature. Preferably, wire bonding C is made of copper wire, which has good thermal conductivity, with a thermal conductivity of approximately 400 W / m*K, which is much greater than the thermal conductivity of the epoxy resin used for chip packaging (0.2–0.4 W / m*K), thus improving the speed of temperature detection.
[0034] The second pad, PAD2, is located at the source of the power transistor, where the transistor's on-resistance R passes through. DS(on) The temperature at this point after the voltage drop can indirectly reflect the actual temperature of the power transistor by detecting the temperature at this point.
[0035] Furthermore, the power transistor is a discrete device and is a vertical power transistor. The top of the power transistor is the source, and the back is the drain. The first pad covers the top of the power transistor chip. In this embodiment, the power transistor is a VDMOS (Vertical Double-diffused Metal-Oxide-Semiconductor Field-Effect Transistor). Figure 4 This is a schematic diagram of the structural layout of the top of the vertical power transistor in an embodiment of this utility model. Figure 4 As shown, the source PAD3 and gate PAD4 of the power transistor are both located at the top (front) of the power transistor, while the drain is located at the back (side) of the power transistor. Figure 4 The diagram shown is on the opposite side. The second pad, PAD2, is preferably positioned in the middle of the source electrode, PAD3, of the power transistor for more accurate temperature detection.
[0036] Preferably, the temperature detection circuit B1 is located below or beside the first pad PAD1, making the temperature detection circuit B1 more suitable for detecting the temperature of the first pad PAD1. Figure 3 In the embodiment shown, the temperature detection circuit B1 is located next to the first pad PAD1.
[0037] In such Figure 1 In the prior art shown, the temperature of the power transistor is mainly achieved through a temperature sampling circuit A1 disposed on the same chip substrate. In a typical implementation, the thermal conductivity of the chip substrate is approximately 148 W / m*K. By controlling the wire bonding length and increasing the number of wires, a good temperature detection effect can be achieved. For example, the thermal conductivity of copper wire is approximately 400 W / m*K. If the distance between the device used for temperature sampling in the temperature detection circuit B1 and the power transistor is approximately 200 μm, the thermal conductivity through the substrate is 148 / 200 μm = 740 KW*K. To achieve the same effect as the prior art, the wire bonding length can be selected as (400 W / m*K) / (740 KW*K) = 0.54 mm. That is, the solution of this utility model embodiment can achieve the same temperature detection effect as the prior art, but the design difficulty and design cost of this utility model are far lower than those of the prior art.
[0038] Preferably, the wire length is 0.3mm to 0.5mm. Because the thermal conductivity of copper wire is greater than that of the substrate, controlling its length within the range of 0.3mm to 0.5mm can achieve better technical results.
[0039] Figure 5 This is a schematic diagram of another embodiment of the power tube temperature detection device in this utility model. For example... Figure 5As shown, preferably, multiple first pads PAD1 are provided. Multiple bonding wires C are used, and their number corresponds to the number of first pads PAD1. The multiple first pads PAD1 are all located near the temperature detection circuit B1, for example, they can all be located around the temperature detection circuit B1, or selectively located beside or above the temperature detection circuit B1. The first ends of the multiple bonding wires C are soldered one-to-one to the multiple first pads PAD1. The second ends of the bonding wires C are all soldered to second pads PAD2. The second ends of the bonding wires C are soldered to different positions on the second pads PAD2. Since some temperature is lost when the first pads PAD1 are transferred through the bonding wires C, multiple bonding wires C can be used to increase the accuracy of the detection.
[0040] Figure 6 This is a schematic diagram of the temperature detection circuit in an embodiment of this utility model. Figure 3 and Figure 5 The temperature detection circuit B1 in the middle can be specifically described as follows: Figure 6 The circuit structure shown is an implementation. Of course, those skilled in the art will know that other circuit structures with the same function can also be used to implement the temperature detection function.
[0041] like Figure 6 As shown, the temperature detection circuit includes a temperature sampling diode D1, a DC current source I1, and a comparator U1. The voltage drop of the temperature sampling diode D1 has a negative temperature characteristic. That is, when the temperature rises, the forward voltage drop of the temperature sampling diode D1 decreases, and when the temperature falls, the forward voltage drop of the temperature sampling diode D1 increases. This is a common physical characteristic of diodes. The DC current source I1 drives the temperature sampling diode D1. A reference voltage source is also included to provide a reference voltage Vref. The positive input terminal of comparator U1 receives the reference voltage Vref, and the inverting input terminal receives the voltage of the temperature sampling diode D1. That is, the inverting input terminal of comparator U1 is connected to the anode of the temperature sampling diode D1, and the cathode of the temperature sampling diode D1 is connected to ground. Comparator D1 outputs a temperature detection signal. The temperature detection signal can be subsequently input to the driver control chip to generate a shutdown signal when the temperature is too high, thereby turning off the power transistor in the power transistor chip and protecting the power transistor. Figure 6 In the circuit shown, since the voltage drop of the temperature sampling diode D1 has a negative temperature characteristic, the value of the anode voltage VBE of the temperature sampling diode D1 decreases as the temperature rises, while the reference voltage Vref does not change with the temperature. When the temperature is higher than the protection point, the anode voltage VBE will be lower than the reference voltage Vref. At this time, the comparator U1 flips and outputs a temperature detection signal as a protection signal for the power transistor.
[0042] Figure 7This is a schematic diagram of the drive control circuit in an embodiment of the present invention. The drive controller chip includes a drive control circuit, such as... Figure 7 As shown, the drive control circuit includes a logic OR circuit, an upper drive circuit X1, a lower drive circuit X2, an upper drive transistor MP1, and a lower drive transistor MN1. The first input of the logic OR circuit receives a PWM signal. The second input of the logic OR circuit receives a protection signal FAULT. The protection signal FAULT includes a temperature detection signal; however, it can also include other types of signals. The logic OR circuit outputs a first drive signal.
[0043] The upper driving circuit X1 receives the first driving signal, amplifies it, and outputs the second driving signal. The lower driving circuit X2 receives the first driving signal, amplifies it, and outputs the third driving signal. The upper driving transistor MP1 is a PMOS transistor, with its first terminal connected to the power supply voltage, and its gate receiving the second driving signal output by the upper driving circuit X1. The lower driving transistor MN1 is an NMOS transistor, with its first terminal connected to ground, its second terminal connected to the second terminal of the upper driving transistor MP1, and its gate receiving the third driving signal output by the lower driving circuit X2. Figure 6 In this configuration, the first terminal of the upper driving transistor MP1 is the source of the PMOS transistor, and the second terminal of MP1 is the drain of the PMOS transistor. The first terminal of the lower driving transistor MN1 is the drain of the NMOS transistor, and the second terminal of MN1 is the source of the NMOS transistor. The common terminal of the upper driving transistor MP1 and the lower driving transistor MN1 outputs the fourth driving signal to the power transistor POERMOS in the power transistor chip.
[0044] exist Figure 7 In the circuit diagram shown, when the protection signal FAULT is low, regardless of the PWM signal state, the first drive signal output by the logic OR circuit is low, which will turn off the power transistor POERMOS in the power transistor chip. Combined with... Figure 6 As shown in the circuit, when the temperature is too high, the anode voltage VBE will be lower than the reference voltage Vref. At this time, the comparator U1 flips and outputs a low-level temperature detection signal as a protection signal to the logic OR circuit, which protects the power transistor POERMOS.
[0045] The above description is an explanation of the present utility model and not a limitation thereof. The scope of the present utility model is defined by the claims. The present utility model can be modified in any form without departing from its basic structure.
Claims
1. A power transistor temperature detection device, characterized in that, This device is used to detect the temperature of the power transistor in a power stage chip; the power stage chip includes a driver controller chip and a power transistor chip; the driver controller chip is used to generate a control signal; the power transistor chip includes a power transistor; the power transistor receives the control signal and turns on or off according to the control signal; The power transistor temperature detection device includes: The first pad is located on the driver controller chip; The second pad is disposed at the source of the power transistor on the power transistor chip; Wire bonding, wherein the two ends of the wire bonding are respectively soldered to the first pad and the second pad; A temperature detection circuit, located in the drive controller chip, is used to detect the temperature of the first pad and output a temperature detection signal to the drive controller chip.
2. The power tube temperature detection device according to claim 1, characterized in that: The bonding wire is made of copper wire.
3. The power tube temperature detection device according to claim 1, characterized in that: The temperature detection circuit is located below or beside the first pad.
4. The power tube temperature detection device according to claim 1, characterized in that: The first pad is provided in multiple ways; the bonding wires are multiple in number and the number corresponds to the number of the first pads; the first ends of the multiple bonding wires are soldered to the multiple first pads one by one; the second ends of the bonding wires are all soldered to the second pads; the second ends of the bonding wires are soldered to different positions of the second pads.
5. The power tube temperature detection device according to claim 1, characterized in that: The length of the bonding wire is 0.3mm to 0.5mm.
6. The power tube temperature detection device according to claim 1, characterized in that: The power transistor is a discrete device and is a vertical power transistor; a source electrode is provided at the top of the power transistor, and the first pad is provided at the source electrode at the top of the power transistor chip.
7. The power tube temperature detection device according to claim 1, characterized in that, The temperature detection circuit includes: A temperature sampling diode, wherein the forward voltage drop of the temperature sampling diode has a negative temperature characteristic; A DC current source is used to drive the temperature sampling diode; A reference voltage source is used to provide a reference voltage. The comparator receives the reference voltage at its positive input terminal and the forward voltage of the temperature sampling diode at its inverting input terminal. The comparator outputs a temperature detection signal.
8. The power tube temperature detection device according to claim 1, characterized in that, The drive controller chip includes a drive control circuit, which includes: The logic OR circuit has a first input terminal for receiving a PWM signal and a second input terminal for receiving a protection signal, including a temperature detection signal. The logic OR circuit outputs a first drive signal, and the control signal turns off the power transistor according to the first drive signal.
9. The power tube temperature detection device according to claim 8, characterized in that, The drive control circuit also includes: The upper driving circuit receives the first driving signal, amplifies it, and then outputs the second driving signal. The lower drive circuit receives the first drive signal, amplifies it, and then outputs the third drive signal. An upper driving transistor, the first terminal of which is connected to a power supply voltage, and the gate of which receives the second driving signal; The lower driving transistor is of the opposite type to the upper driving transistor; the first end of the lower driving transistor is connected to the ground terminal, the second end of the lower driving transistor is connected to the second end of the upper driving transistor, and the gate of the lower driving transistor receives the third driving signal. The common terminal of the upper driving transistor and the lower driving transistor outputs a control signal to control the power transistor to turn on or off.