Power supply device and temperature regulation method

Abstract

A power supply device includes a power switch, a control circuit, and a temperature sensing circuit. The power switch converts an input voltage signal into an output voltage signal according to a control signal; the control circuit generates a control signal to drive the power switch and adjusts the control signal according to an over-temperature protection signal to regulate the temperature of the power switch; the temperature sensing circuit includes a reference voltage generation circuit, a metal-oxide-semiconductor transistor, and a comparator circuit. The reference voltage generation circuit generates a reference voltage signal based on a first reference voltage and an input voltage signal. The metal-oxide-semiconductor transistor is disposed on the power switch, with its drain connected to the input voltage signal, its gate connected to a second reference voltage, and its source generating a sensed voltage signal. The comparator circuit compares the sensed voltage signal with the reference voltage signal to generate an over-temperature protection signal.

Description

Technical Field

[0001] This invention relates to a power supply device and a temperature regulation method, and more particularly to a power supply device and a temperature regulation method capable of accurately monitoring and real-time adjusting the temperature of a power switch. Prior Technology

[0002] In modern electronic systems, power management technology plays a crucial role, with power switches being widely used in power supply devices to achieve voltage or current conversion and regulation. In high-power applications, such as amplifiers, switching regulators, linear regulators, LED drivers, and battery management ICs, power MOSFETs (Power MOS) are common power switching components due to their high efficiency and fast response characteristics. To improve the power handling capability and reliability of the system, conventional technology often employs a multi-chip module (MCM) packaging architecture, integrating the Power MOS and control circuitry into a single package. However, this configuration faces several technical challenges in practical applications, particularly issues related to temperature sensing and thermal management.

[0003] In previous technologies, temperature monitoring of power switches typically relied on traditional bipolar junction transistor (BJT) temperature sensing elements. However, when power switches are implemented using Power MOS and integrated into an MCM architecture, due to process differences, BJT temperature sensing elements cannot be directly placed on the Power MOS platform. This results in the control circuit only being able to indirectly sense the temperature around the Power MOS, rather than the actual temperature of the Power MOS itself. Generally, current flowing through a Power MOS generates significant heat, directly affecting its operating temperature. However, the indirect sensing method makes the temperature data inaccurate and unable to effectively reflect the thermal state of the Power MOS. Furthermore, when the Power MOS overheats, the heat must be transferred to the temperature sensing element at the control circuit level to trigger the protection mechanism. This delay can lead to a slow response, or even cause the Power MOS to burn out before protection is activated, affecting the reliability and stability of the system.

[0004] Therefore, the industry urgently needs a technical solution that can accurately sense the temperature of power switches in order to improve the performance and reliability of power supply devices. Summary of the Invention

[0005] Therefore, the present invention mainly provides a power supply device and a temperature regulation method, which can accurately sense the temperature of the power switch.

[0006] This invention discloses a power supply device for receiving an input voltage signal and generating an output voltage signal. It includes a power switch for converting the input voltage signal into the output voltage signal according to a control signal; a control circuit for generating the control signal to drive the power switch and adjusting the control signal according to a first over-temperature protection signal to regulate the operating temperature of the power switch; and a temperature sensing circuit including a reference voltage generation circuit for generating a reference voltage signal based on a first reference voltage and the input voltage signal; and a first metal-oxide-semiconductor transistor. The first metal-oxide-semiconductor transistor is disposed on the power switch. The first transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to a second reference voltage, and a source generating a first sense voltage signal. A first comparator circuit is electrically connected to the source of the first transistor to receive the first sense voltage signal, and electrically connected to the reference voltage generation circuit and the control circuit to compare the first sense voltage signal with the reference voltage signal to generate the first over-temperature protection signal, and output the first over-temperature protection signal to the control circuit.

[0007] This invention also discloses a temperature regulation method for a power supply device. A power switch in the power supply device converts an input voltage signal into an output voltage signal according to a control signal. The temperature regulation method includes generating a reference voltage signal based on a first reference voltage and the input voltage signal; disposing a first metal-oxide-semiconductor transistor on the power switch, wherein the first metal-oxide-semiconductor transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to a second reference voltage, and a source generating a first sense voltage signal; and comparing the first sense voltage signal with the reference voltage signal to generate a first over-temperature protection signal, wherein the first over-temperature protection signal is used to adjust the control signal to regulate the operating temperature of the power switch. Simple Explanation of the Diagram

[0008] Figure 1 is a schematic diagram of a power supply device according to one embodiment of the present invention. Figure 2 is a schematic diagram of the threshold voltage versus temperature relationship of a metal oxide semiconductor transistor. Figure 3 is a schematic diagram of the relationship between the first sense voltage signal and the drain-source voltage in Figure 1. Figure 4 is a schematic diagram of a reference voltage generation circuit according to one embodiment of the present invention. Figures 5A, 5B, and 5C are schematic diagrams illustrating the changes in the relevant signals in Figure 1 at different temperatures. Figures 6A and 6B are schematic diagrams illustrating the changes in relevant signals before and after the compensation mechanism is added, respectively. Figures 7A and 7B are schematic diagrams illustrating the timing of the over-temperature protection signal level change when the compensation mechanism is not added and when the compensation mechanism is added, respectively. Figure 8 is a schematic diagram of a power supply device according to one embodiment of the present invention. Figure 9 is a schematic diagram of a temperature regulation process according to one embodiment of the present invention. Implementation

[0009] When power switches are implemented using Power MOS and integrated into an MCM architecture, a feasible technique for sensing the temperature of the Power MOS is to place a small metal-oxide-semiconductor (MOSFET) as a temperature sensing element around the Power MOS, utilizing the negative temperature characteristic of its threshold voltage (Vth) for temperature sensing. However, this method is limited in practical applications by input voltage variations. Specifically, changes in the drain-source voltage of the MOSFET can induce channel length modulation, causing the sensed voltage to vary unintended with the input voltage, thereby reducing the accuracy of temperature sensing.

[0010] To address the aforementioned problems, this invention provides a power supply device and its temperature regulation method. By setting a temperature sensing element on the power switch and combining it with input voltage slope compensation technology, the device achieves accurate sensing and real-time adjustment of the power switch temperature, thereby improving the system's performance and reliability.

[0011] Please refer to Figure 1, which is a schematic diagram of a power supply device 10 according to one embodiment of the present invention. The power supply device 10 includes a power switch 12, a control circuit 14, and a temperature sensing circuit 16. The power supply device 10 can receive an input voltage signal VIN and generate an output voltage signal VOUT, and can sense the temperature on the power switch 12 and control the power switch 12 according to the sensed temperature, thereby realizing temperature regulation of the power switch 12. Specifically, the power switch 12 converts the input voltage signal VIN into an output voltage signal VOUT according to a control signal VG generated by the control circuit 14. The control circuit 14 is responsible for generating the control signal VG to drive the power switch 12, and adjusting the control signal VG according to a first over-temperature protection signal OTP1 provided by the temperature sensing circuit 16, thereby regulating the operating temperature of the power switch 12. The temperature sensing circuit 16 includes a reference voltage generation circuit 161, a first metal-oxide-semiconductor transistor 162, and a first comparator circuit 163. The reference voltage generation circuit 161 generates a reference voltage signal VREFOT (also known as a slope-compensated reference voltage signal VREFOT) based on a first reference voltage VREF and an input voltage signal VIN. In one embodiment, the first reference voltage VREF is preferably a fixed value, which can be determined according to the temperature threshold used for over-temperature protection. A first metal-oxide-semiconductor transistor 162, as a temperature sensing element, is disposed on the power switch 12. Its drain is electrically connected to the input voltage signal VIN, its gate is electrically connected to a second reference voltage VR, and its source generates a first sensing voltage signal Vsense1. Preferably, the second reference voltage VR is a fixed value, so that the first metal-oxide-semiconductor transistor 162 can operate under a fixed gate voltage, thereby more accurately reflecting the effect of temperature changes on the first sensing voltage signal Vsense1, and improving the stability and accuracy of temperature sensing. Furthermore, one end of a load 164 is electrically connected between the source of the first metal-oxide-semiconductor transistor 162 and the positive terminal (+) of the first comparator circuit 163, and the other end is electrically connected to ground. Referring to Figure 1, in this embodiment, the load 164 is implemented using a resistor RL10. The positive terminal (+) of the first comparator circuit 163 receives a first sense voltage signal Vsense1, and its negative terminal (-) is electrically connected to a reference voltage generation circuit 161 to receive a reference voltage signal VREFOT. This is used to compare the first sense voltage signal Vsense1 with the reference voltage signal VREFOT to generate a first over-temperature protection signal OTP1, which is then output to the control circuit 14, causing the control circuit 14 to adjust the control signal VG accordingly.

[0012] In this embodiment, the power switch 12 is a power MOSFET, the operating principle of which is well known to those skilled in the art. In this embodiment, the first MOSFET 162 and the power MOSFET system implementing the power switch 12 are manufactured using the same process. In one embodiment, the power switch 12, control circuit 14, and temperature sensing circuit 16 can be integrated into a multi-chip module (MCM) package architecture. Specifically, the first MOSFET 162 of the power switch 12 and temperature sensing circuit 16 is disposed on one chip, while the reference voltage generation circuit 161, the first comparator circuit 163, and the load 164 of the control circuit 14 and temperature sensing circuit 16 are disposed on another chip. These two chips can be integrated into a single package, and their connection is achieved through wire bonding. This configuration allows the temperature sensing circuit 16 to directly sense the temperature on the power switch 12 through the first MOSFET 162, significantly improving the accuracy and immediacy of sensing compared to traditional indirect sensing methods.

[0013] In detail, please refer to Figure 2, which is a schematic diagram of curve 20. Curve 20 represents the relationship between a threshold voltage Vth of the first metal-oxide-semiconductor transistor 162 and temperature. As shown in curve 20, the threshold voltage Vth decreases with increasing temperature, exhibiting a negative temperature coefficient characteristic. This characteristic allows the first metal-oxide-semiconductor transistor 162 to convert temperature changes into changes in the first sensing voltage signal Vsense1. Specifically, when the temperature rises, the threshold voltage Vth decreases, leading to an increase in the first sensing voltage signal Vsense1; conversely, when the temperature decreases, the threshold voltage Vth increases, and the first sensing voltage signal Vsense1 decreases. Therefore, the first sensing voltage signal Vsense1 has a positive temperature coefficient characteristic and can be used as an indicator of temperature sensing.

[0014] However, variations in the input voltage signal VIN can affect the accuracy of the first sense voltage signal Vsense1 due to channel length modulation. For example, refer to Figure 3, which illustrates curves 30, 32, and 34. Curves 30, 32, and 34 represent the relationship between the first sense voltage signal Vsense1 and the drain-source voltage VDS of the first metal-oxide-semiconductor transistor 162 when the resistance of resistor RL10 is 100 ohms, 1K ohms, and 10K ohms, respectively. As shown in Figure 3, at the same drain-source voltage VDS, the higher the resistance of resistor RL10, the lower the first sense voltage signal Vsense1. Furthermore, at the same resistance of resistor RL10 and the same temperature, the first sense voltage signal Vsense1 changes with the drain-source voltage VDS due to the channel length modulation effect.

[0015] The channel length modulation effect refers to the slight shortening of the equivalent channel length of the first metal-oxide-semiconductor transistor 162 when the drain-source voltage VDS increases, resulting in an increase in output current and causing an additional offset in the first sense voltage signal Vsense1. In other words, even if the temperature remains constant, the first sense voltage signal Vsense1 will still change with the drain-source voltage VDS. Since the drain-source voltage VDS is related to the input voltage signal VIN, this causes the first sense voltage signal Vsense1 to exhibit unexpected variations with the input voltage signal VIN, thus reducing the accuracy of temperature sensing. To solve this problem, the present invention correlates the reference voltage signal VREFOT with the input voltage signal VIN, causing it to increase with the increase of the input voltage signal VIN or decrease with the decrease of the input voltage signal VIN (i.e., input voltage slope compensation technology). In this way, the dynamic adjustment mechanism of the reference voltage signal VREFOT can offset or compensate for the non-temperature-dependent changes in the first sense voltage signal Vsense1 caused by the channel length modulation effect, ensuring that the comparison result between the first sense voltage signal Vsense1 and the reference voltage signal VREFOT can reflect the real temperature changes.

[0016] Furthermore, the first comparator circuit 163 compares the first sensed voltage signal Vsense1 with the compensation reference voltage signal VREFOT. When the first sensed voltage signal Vsense1 exceeds the compensation reference voltage signal VREFOT, it indicates that the power switch 12 is overheating. The first comparator circuit 163 generates a first over-temperature protection signal OTP1 or adjusts the level of the first over-temperature protection signal OTP1, notifying the control circuit 14 to adjust the control signal VG, for example, by pulling the control signal VG low to reduce the conduction level of the power switch 12 or turn off the power switch 12, thereby preventing overheating damage.

[0017] In short, in the power supply device 10, the reference voltage signal VREFOT generated by the reference voltage generation circuit 161 is related not only to the fixed first reference voltage VREF, but also to the input voltage signal VIN. This allows the reference voltage signal VREFOT to dynamically track changes in the input voltage signal VIN, thereby effectively compensating for the influence of channel length modulation effect on temperature sensing. In other words, the operation of the reference voltage generation circuit 161 can be considered as combining the first reference voltage VREF with a portion of the input voltage signal VIN to form the reference voltage signal VREFOT. Thus, the reference voltage signal VREFOT can dynamically track changes in the input voltage signal VIN, offsetting or compensating for the influence of channel length modulation effect on temperature sensing. Therefore, the present invention can significantly improve the accuracy of temperature sensing and enhance the reliability and stability of the system.

[0018] In order for the reference voltage signal VREFOT to dynamically track changes in the input voltage signal VIN, in one embodiment, the reference voltage generation circuit 161 generates the reference voltage signal VREFOT based on the input voltage signal VIN and the first reference voltage VREF, such that it achieves the following relationship:

[0019] (Formula 1) VREFOT = VREF + VIN × Gain;

[0020] Here, Gain is a gain coefficient. In this way, by adjusting the gain coefficient Gain, the reference voltage signal VREFOT can be dynamically compensated as the input voltage signal VIN changes, thereby offsetting or compensating for the error introduced by the first sense voltage signal Vsense1 due to the variation of the input voltage signal VIN.

[0021] It should be noted that the implementation of the reference voltage generation circuit 161 is not limited to a specific architecture, as long as the reference voltage signal VREFOT can change with the input voltage signal VIN, such as the relationship in Equation 1. For example, please refer to Figure 4, which is a schematic diagram of a reference voltage generation circuit 40 according to one embodiment of the present invention. The reference voltage generation circuit 40 is used to implement the reference voltage generation circuit 161, and includes a voltage divider circuit 400, a first voltage-to-current conversion circuit 402, a first current mirror 404, a second voltage-to-current conversion circuit 406, a second current mirror 408, and a current-to-voltage conversion circuit 410. The voltage divider circuit 400 is composed of resistors R1 and R2 connected in series, and is electrically connected to the input voltage signal VIN to divide the input voltage signal VIN to generate a voltage divider signal Vdiv, that is, Vdiv = VIN × (R1 / (R1 + R2)). The first voltage-to-current conversion circuit 402 consists of an operational amplifier 4020, a resistor 4022, and a metal-oxide-semiconductor transistor 4024. Its operation is well-known in the art. In short, the first voltage-to-current conversion circuit 402 converts the voltage divider signal Vdiv into a first current I1. The first current mirror 404 consists of transistors 4040 and 4042, used to convert the first current I1 into a second current I2, where I2 = I1 × M, and M is the current mirror factor of the first current mirror 404, typically determined by the size ratio of the two transistors 4040 and 4042 in the first current mirror 404. It provides the function of current amplification, reduction, or mirroring, and its operation is well-known in the art. The second voltage-to-current conversion circuit 406 has the same circuit architecture as the first voltage-to-current conversion circuit 402, consisting of an operational amplifier 4060, a resistor 4062, and a metal-oxide-semiconductor transistor 4064, used to convert the first reference voltage VREF into a third current I3. The second current mirror 408 is composed of transistors 4080 and 4082 and performs a mirrored replication of the current to convert the third current I3 output by the second voltage-to-current conversion circuit 406 into a fourth current I4. The current-to-voltage conversion circuit 410 is implemented by a resistor 4100, which adds the second current I2 and the fourth current I4 and converts the added current into a voltage signal to generate a reference voltage signal VREFOT.

[0022] In the reference voltage generation circuit 40, the component of the input voltage signal VIN is adjusted by the voltage divider circuit 400 and the current mirror multiplier M of the first current mirror 404, and then added to the component of the first reference voltage VREF to form the compensation reference voltage signal VREFOT. In this case, the gain coefficient Gain can be expressed as:

[0023] (Equation 2) Gain = (R1 / (R1 + R2)) / M;

[0024] Where (R1 / (R1 + R2)) is the ratio of the voltage divider signal Vdiv to the input voltage signal VIN. In other words, the component of the input voltage signal VIN in the reference voltage signal VREFOT is related to the ratio of the voltage divider signal Vdiv to the input voltage signal VIN and the multiplier M of the first current mirror 404. Therefore, by adjusting resistors R1 and R2 and the current mirror multiplier M, the component of the input voltage signal VIN in the reference voltage signal VREFOT can be precisely controlled, thereby modulating the gain coefficient Gain to match the characteristics of the first metal-oxide-semiconductor transistor 162, ensuring that the compensation reference voltage signal VREFOT can accurately compensate for the variation in the first sense voltage signal Vsense1 caused by the input voltage signal VIN.

[0025] It is important to note that the gain coefficient (Gain) can be adjusted during the production or manufacturing stage of the power supply device 10 to ensure that the reference voltage signal VREFOT accurately matches the characteristics of the first metal-oxide-semiconductor transistor 162. Specifically, the manufacturer can optimize the gain coefficient (Gain) by detecting the first sense voltage signal Vsense1 under different input voltage signals VIN and dynamically adjusting resistors R1, R2, and the current mirror multiplier M. This adjustment can be achieved through laser trimming or a programmable resistor network to ensure that each power supply device achieves optimal temperature compensation before leaving the factory. Furthermore, during system operation, if environmental conditions or component aging cause characteristic drift, the gain coefficient (Gain) can also be fine-tuned through software or hardware feedback mechanisms to maintain the accuracy of temperature sensing.

[0026] Furthermore, the reference voltage generation circuit 40 is merely one embodiment of the reference voltage generation circuit 161. Those skilled in the art can achieve the same function or make different modifications using various electronic components or modules, and are not limited thereto. For example, the voltage divider circuit 400 can be implemented by series resistors or by a digitally controlled adjustable voltage divider. The first voltage-to-current conversion circuit 402 and the second voltage-to-current conversion circuit 406 can be implemented by a combination of operational amplifiers, resistors, and metal-oxide-semiconductor transistors, or by a voltage-controlled current source (VCCS) module or any circuit that can convert voltage to current. The first current mirror 404 and the second current mirror 408 are used to amplify, reduce, and mirror current, and can be implemented by any circuit or module with the same function. The current-to-voltage conversion circuit 410 is used to convert current to voltage, and is not limited to resistors, but can be implemented by any circuit or module with the same function. Furthermore, it is worth noting that the resistors used in the first voltage-to-current conversion circuit 402, the second voltage-to-current conversion circuit 406, and the current-to-voltage conversion circuit 410 are preferably resistors of the same resistance value to ensure a consistent temperature coefficient in the circuit, reduce errors caused by temperature changes, and improve system stability. However, depending on design requirements, resistors of different resistance values ​​or adjustable resistors can also be used to achieve more flexible adjustment functions.

[0027] To more clearly illustrate the effect of the compensation mechanism of this invention, please refer to Figures 5A-5C, 6A, 6B, 7A, and 7B. First, assume that the system requires a temperature protection level above 150°C for the power switch 12 (i.e., the temperature threshold for over-temperature protection). Figures 5A, 5B, and 5C are schematic diagrams showing the changes in the first sense voltage signal Vsense1, the compensation reference voltage signal VREFOT, and the first over-temperature protection signal OTP1 for different input voltage signals VIN when the power switch 12 operates at 25°C, 130°C, and 170°C. In Figures 5A, 5B, and 5C, the horizontal axis represents the input voltage signal VIN, the vertical axis represents voltage, curves 50, 53, and 56 represent the compensation reference voltage signal VREFOT, curves 51, 54, and 57 represent the first sense voltage signal Vsense1, and curves 52, 55, and 58 represent the first over-temperature protection signal OTP1. As shown in Figures 5A, 5B, and 5C, both the first sense voltage signal Vsense1 and the compensation reference voltage signal VREFOT change in the same direction as the input voltage signal VIN. That is, when the input voltage signal VIN increases, both the first sense voltage signal Vsense1 and the compensation reference voltage signal VREFOT also increase. Furthermore, comparing Figures 5A, 5B, and 5C, it can be seen that when the temperature of the power switch 12 is below 150°C (i.e., Figures 5A and 5B), the first over-temperature protection signal OTP1 remains at a low level, and the power switch 12 can continue to operate. However, when the temperature of the power switch 12 reaches 150°C (i.e., Figure 5C), the first over-temperature protection signal OTP1 turns to a high level to notify the control circuit 14 to adjust the control signal VG, for example, by pulling the control signal VG low to reduce the conduction level of the power switch 12 or to turn off the power switch 12, thereby preventing overheating damage.

[0028] Next, please refer to Figures 6A and 6B. Figures 6A and 6B are schematic diagrams showing the changes in the first sense voltage signal Vsense1 and the first over-temperature protection signal OTP1 before and after the compensation mechanism of the present invention is added, respectively. Figures 6A and 6B are a continuation of the example in Figure 5A, i.e., the power switch 12 is operating at 25°C. The horizontal axis represents the input voltage signal VIN, and the vertical axis represents the voltage. Curve 50 represents the compensation reference voltage signal VREFOT, and curve 51 represents the first sense voltage signal Vsense1. In addition, in Figures 6A and 6B, curve 60 represents the level of the first reference voltage VREF, curve 61 represents the first over-temperature protection signal OTP1 without the compensation mechanism of the present invention, and curve 62 represents the first over-temperature protection signal OTP1 after the compensation mechanism of the present invention is added. The case where the compensation mechanism of the present invention is not added here means that the first comparison circuit 163 compares the first sense voltage signal Vsense1 with the first reference voltage VREF to generate the first over-temperature protection signal OTP1. First, as shown in Figure 6A, due to the channel length modulation effect, the first sense voltage signal Vsense1 changes not only with temperature but also with the input voltage signal VIN. Therefore, at point P, the first sense voltage signal Vsense1 touches (is greater than or equal to) the first reference voltage VREF, causing the first over-temperature protection signal OTP1 to switch from a low level to a high level at point N. However, at this time, the power switch 12 still operates at 25°C. It is only because the input voltage signal VIN increases that the first sense voltage signal Vsense1 touches the first reference voltage VREF, which in turn causes the first over-temperature protection signal OTP1 to switch from a low level to a high level at point N, where no switching is required, and thus the power switch 12 is turned off. In contrast, as shown in Figure 6B, after adding the compensation mechanism of the present invention, the first sense voltage signal Vsense1 will still change with the input voltage signal VIN due to the channel length modulation effect, but at the same time, the compensation reference voltage signal VREFOT will also adaptively change with the input voltage signal VIN. Therefore, as shown in Figure 6B, the first over-temperature protection signal OTP1 after incorporating the compensation mechanism of this invention will not erroneously switch to a high level, and can more accurately reflect temperature changes, eliminating the influence of input voltage signal VIN variations on sensing.

[0029] Further, please refer to Figures 7A and 7B. Figures 7A and 7B are schematic diagrams showing the timing of level changes of the first over-temperature protection signal OTP1 before and after the compensation mechanism of the present invention is added. In Figures 7A and 7B, the horizontal axis represents the temperature of the power switch 12, and the vertical axis represents the voltage. Curves 70 and 71 represent the first sensing voltage signal Vsense1 under higher and lower input voltage signals VIN, respectively. Curve 73 represents the level of the first reference voltage VREF. Curves 74 and 75 represent the first over-temperature protection signal OTP1 under different conditions without the compensation mechanism of the present invention. Curves 78 and 79 represent the first over-temperature protection signal OTP1 under different conditions after the compensation mechanism of the present invention is added. Curves 76 and 77 represent the compensation reference voltage signal VREFOT under higher and lower input voltage signals VIN, respectively. First, as mentioned earlier, due to the channel length modulation effect, the first sense voltage signal Vsense1 changes not only with temperature but also with the input voltage signal VIN. Therefore, as shown in Figures 7A and 7B, under the same temperature of the power switch 12, the level of curve 70 is higher than that of curve 71. In this case, as shown in Figure 7A, at point P1, curve 70 (corresponding to the first sense voltage signal Vsense1 under the higher input voltage signal VIN) touches (is greater than or equal to) curve 73 (the first reference voltage VREF), causing curve 74 (the first over-temperature protection signal OTP1) to switch from a low level to a high level at point N1, and at this time the temperature of the power switch 12 is t1. At point P2, curve 71 (corresponding to the first sense voltage signal Vsense1 under the lower input voltage signal VIN) touches (is greater than or equal to) curve 73 (the first reference voltage VREF), causing curve 75 (the first over-temperature protection signal OTP1) to switch from a low level to a high level at point N2, and at this time the temperature of power switch 12 is t2. Therefore, without the compensation mechanism of this invention, the over-temperature protection critical temperature of power switch 12 changes from t1 to t2 under high and low input voltage signals VIN. This phenomenon causes the trigger point of over-temperature protection to be inconsistent with changes in input voltage VIN, failing to accurately reflect the actual temperature of power switch 12, thus affecting the reliability and safety of the system.

[0030] Conversely, as shown in Figure 7B, at point P3, curve 70 (corresponding to the first sense voltage signal Vsense1 under the higher input voltage signal VIN) touches (is greater than or equal to) curve 76 (corresponding to the compensation reference voltage signal VREFOT under the higher input voltage signal VIN), causing curve 78 (the first over-temperature protection signal OTP1) to switch from a low level to a high level at point N3, and at this time the temperature of power switch 12 is t3. At point P4, curve 71 (corresponding to the first sense voltage signal Vsense1 under the lower input voltage signal VIN) touches (is greater than or equal to) curve 77 (corresponding to the compensation reference voltage signal VREFOT under the lower input voltage signal VIN), causing curve 79 (the first over-temperature protection signal OTP1) to switch from a low level to a high level at the same point N3, and at this time the temperature of power switch 12 is t3. Therefore, it can be seen that after adding the compensation mechanism of the present invention, the over-temperature protection critical temperature of the power switch 12 remains unchanged at t3 under both high and low input voltage signals VIN. In other words, regardless of how the input voltage signal VIN changes, the trigger temperature of the over-temperature protection of the power switch 12 remains stable at t3 after adding the compensation mechanism of the present invention. This eliminates the influence of input voltage VIN fluctuations on temperature sensing, making the trigger point of over-temperature protection consistent and significantly improving the accuracy and stability of the system.

[0031] Therefore, as shown in Figures 7A and 7B, without the compensation mechanism of the present invention (Figure 7A), the trigger temperature of the over-temperature protection changes with the input voltage signal VIN from t1 to t2, resulting in inconsistency; while with the compensation mechanism of the present invention (Figure 7B), the trigger temperature of the over-temperature protection is fixed at t3 and does not change with the input voltage signal VIN, ensuring consistency and reliability.

[0032] In short, the compensation mechanism of this invention can dynamically adjust the reference voltage signal VREFOT, effectively offsetting or compensating for the influence of channel length modulation effect on the first sensing voltage signal Vsense1, so that the trigger point of over-temperature protection remains consistent under different input voltage signals VIN, ensuring the accuracy of temperature sensing and the stability of the system.

[0033] It should be noted that in the power supply device 10, the temperature sensing circuit 16 senses the temperature of the power switch 12 through a single first metal-oxide-semiconductor transistor 162. However, it is not limited to this; those skilled in the art can derive the method by using two or more metal-oxide-semiconductor transistors as temperature sensing elements to sense the temperature at different locations on the power switch 12. For example, please refer to Figure 8, which is a schematic diagram of a power supply device 80 according to one embodiment of the present invention. The power supply device 80 is derived from the power supply device 10, so the same components are represented by the same symbols. The power supply device 80 differs from the power supply device 10 in that the temperature sensing circuit 16 further includes a second metal-oxide-semiconductor transistor 862, a second comparator circuit 863, and a load 864. Referring to Figure 8, in this embodiment, the load 864 is implemented using a resistor RL80. In the MCM packaging architecture, the power switch 12, the first metal-oxide-semiconductor transistor 162, and the second metal-oxide-semiconductor transistor 862 are mounted on one chip, while the control circuit 14, the reference voltage generation circuit 161, the first comparator circuit 163, the second comparator circuit 863, and the loads 164 and 864 are mounted on another chip. The second metal-oxide-semiconductor transistor 862 serves as another temperature sensing element, capable of sensing the temperature at different locations on the power switch 12 compared to the first metal-oxide-semiconductor transistor 162. Otherwise, the operation of the second metal-oxide-semiconductor transistor 862 and the second comparator circuit 863 is largely the same as that of the first metal-oxide-semiconductor transistor 162 and the first comparator circuit 163. That is, the drain of the second metal-oxide-semiconductor transistor 862 is electrically connected to the input voltage signal VIN, the gate is electrically connected to the second reference voltage VR, and the source generates a second sensing voltage signal Vsense2. Furthermore, one end of resistor RL80 is electrically connected between the source of the second metal-oxide-semiconductor transistor 862 and the positive terminal (+) of the second comparator circuit 863, and the other end is electrically connected to ground. The positive terminal (+) of the second comparator circuit 863 receives the second sensed voltage signal Vsense2, and its negative terminal (-) is electrically connected to the reference voltage generation circuit 161 to receive the reference voltage signal VREFOT. This is used to compare the second sensed voltage signal Vsense2 with the reference voltage signal VREFOT to generate a second over-temperature protection signal OTP2, which is then output to the control circuit 14, allowing the control circuit 14 to adjust the control signal VG accordingly.

[0034] In the power supply device 80, the control circuit 14 can adjust the control signal VG according to the first over-temperature protection signal OTP1 and the second over-temperature protection signal OTP2. It can also add an OR gate to perform an OR operation on these signals to adjust the control signal VG based on the result of the OR operation. That is, when either the first over-temperature protection signal OTP1 or the second over-temperature protection signal OTP2 indicates an over-temperature condition, the control circuit 14 can trigger the protection. Furthermore, the control circuit 14 can also determine the specific location of the temperature anomaly on the power switch 12 based on different over-temperature protection signals, achieving more precise temperature management.

[0035] It should be noted that the power supply device 80 in Figure 8 includes two temperature sensing elements (a first metal-oxide-semiconductor transistor 162 and a second metal-oxide-semiconductor transistor 862). In practice, depending on system requirements and design considerations, those skilled in the art should be able to appropriately place multiple temperature sensing elements at different locations on the power switch 12 and correspondingly configure multiple comparison circuits, not limited to two, to achieve more comprehensive temperature monitoring. Regardless of whether a single or multiple temperature sensing elements are placed on the power switch 12, the power supply device of the present invention can utilize input voltage slope compensation technology to achieve accurate monitoring and real-time adjustment of the power switch temperature, overcoming the shortcomings of inaccurate temperature sensing and response delay in the prior art, and improving the system's performance and reliability.

[0036] The operation of the power supply devices 10 and 80 described above can be summarized as a temperature regulation process 90, as shown in Figure 9. The temperature regulation process 90 includes the following steps:

[0037] Step 900: Begin.

[0038] Step 902: Generate a reference voltage signal VREFOT based on the first reference voltage VREF and the input voltage signal VIN.

[0039] Step 904: The first metal-oxide-semiconductor transistor 162 is disposed on the power switch 12, wherein the drain of the first metal-oxide-semiconductor transistor 162 is electrically connected to the input voltage signal VIN, the gate is electrically connected to the second reference voltage VR, and the source generates a first sensing voltage signal Vsense1.

[0040] Step 906: Compare the first sense voltage signal Vsense1 with the reference voltage signal VREFOT to generate a first over-temperature protection signal OTP1, wherein the first over-temperature protection signal OTP1 is used to adjust the control signal VG to regulate the operating temperature of the power switch 12.

[0041] Step 908: End.

[0042] For detailed instructions on the operation of temperature regulation process 90, please refer to the foregoing description. It will not be repeated here.

[0043] In prior art, temperature monitoring of power switches typically relies on traditional bipolar junction transistor (BJT) temperature sensing elements. Due to manufacturing limitations, BJT temperature sensing elements cannot be directly mounted on the power switch platform, resulting in inaccurate temperature sensing and response delays. This fails to reflect the true temperature of the power switch in a timely manner, increasing the risk of system damage in overheating situations. This invention, by directly mounting a temperature sensing element on the power switch and combining it with input voltage slope compensation technology, achieves precise monitoring and real-time adjustment of the power switch temperature, effectively overcoming the shortcomings of previous methods and improving system performance and reliability.

[0044] In summary, the power supply device and its temperature regulation method of the present invention effectively solve the problems of inaccurate temperature sensing and response delay in the prior art by directly setting a temperature sensing element on the power switch and using input voltage slope compensation technology, thereby realizing accurate monitoring and real-time adjustment of the power switch temperature and improving the system efficiency and reliability. The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the scope of the claims of the present invention shall be covered by the present invention.

[0045] 10: Power supply device

[0046] 12: Power Switch

[0047] 14: Control Circuit

[0048] 16: Temperature sensing circuit

[0049] 161: Reference Voltage Generation Circuit

[0050] 162: First Metal-Oxide-Semiconductor Transistor

[0051] 163: First Comparator Circuit

[0052] 164: Load

[0053] 40: Reference voltage generation circuit

[0054] 400: Voltage divider circuit

[0055] 402: First voltage-to-current conversion circuit

[0056] 4020: Operational Amplifier

[0057] 4022: Resistor

[0058] 4024: Metal-Oxide-Semiconductor Transistor

[0059] 404: First Current Mirror

[0060] 4040, 4042: Transistors

[0061] 406: Second voltage-to-current conversion circuit

[0062] 4060: Operational Amplifier

[0063] 4062: Resistor

[0064] 4064: Metal-Oxide-Semiconductor Transistor

[0065] 408: Second Current Mirror

[0066] 4080, 4052: Transistors

[0067] 410: Current to Voltage Conversion Circuit

[0068] 4100: Resistor

[0069] 20, 30, 32, 34, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 62, 70, 71, 73, 74, 75, 76, 77, 78, 79: Curve

[0070] 80: Power supply device

[0071] 862: Second Metal-Oxide-Semiconductor Transistor

[0072] 863: Second Comparator Circuit

[0073] 90: Temperature Control Procedure

[0074] 900~908: Steps

[0075] VIN: Input voltage signal

[0076] VOUT: Output voltage signal

[0077] VG: Control Signal

[0078] OTP1: First over-temperature protection signal

[0079] OTP2: Second over-temperature protection signal

[0080] VREF: First reference voltage

[0081] VR: Second reference voltage

[0082] VREFOT: Reference Voltage Signal

[0083] Vsense1: First sensing voltage signal

[0084] Vsense2: Second sensing voltage signal

[0085] Vth: Threshold voltage

[0086] VDS: Drain-Source Voltage

[0087] Vdiv: Voltage divider signal

[0088] I1: First current

[0089] I2: Second current

[0090] I3: Third Current

[0091] I4: Fourth Current

[0092] R1: Resistor

[0093] R2: Resistor

[0094] RL10, RL80: Resistors

[0095] M: Magnification of the current mirror

[0096] P, P1, P2, P3, P4, N, N1, N2, N3, N4: Points

[0097] t1, t2, t3: Temperature

Claims

1. A power supply device for receiving an input voltage signal and generating an output voltage signal, comprising: A power switch for converting an input voltage signal into an output voltage signal according to a control signal; a control circuit for generating the control signal to drive the power switch and adjusting the control signal according to a first over-temperature protection signal to regulate the operating temperature of the power switch; and a temperature sensing circuit, comprising: a reference voltage generation circuit for generating a reference voltage signal according to a first reference voltage and the input voltage signal; and a first metal-oxide-semiconductor transistor disposed on the power switch, wherein the first metal-oxide-semiconductor transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to a second reference voltage, and a source. A resistor is electrically connected between the source of the first metal-oxide-semiconductor transistor and a ground terminal, wherein a first sense voltage signal is generated at a common node between the source of the first metal-oxide-semiconductor transistor and the resistor; and a first comparator circuit is electrically connected to the source of the first metal-oxide-semiconductor transistor to receive the first sense voltage signal, and electrically connected to the reference voltage generation circuit and the control circuit to compare the first sense voltage signal with the reference voltage signal to generate the first over-temperature protection signal, and output the first over-temperature protection signal to the control circuit.

2. The power supply device as claimed in claim 1, wherein the power switch, the control circuit, and the temperature sensing circuit are integrated in a multi-chip module (MCM) package architecture, the power switch including a transistor, and the transistor having the same conductivity type as the first metal-oxide-semiconductor transistor.

3. The power supply device as claimed in claim 1, wherein the reference voltage generating circuit comprises: a voltage divider circuit electrically connected to the input voltage signal for generating a voltage-divided signal of the input voltage signal; a first voltage-to-current conversion circuit electrically connected to the voltage divider circuit for converting the voltage-divided signal into a first current; a first current mirror electrically connected to the first voltage-to-current conversion circuit for converting the first current into a second current, the first current and the second current being a multiple of each other; a second voltage-to-current conversion circuit for converting the first reference voltage into a third current; a second current mirror electrically connected to the second voltage-to-current conversion circuit for converting the third current into a fourth current; and a current-to-voltage conversion circuit electrically connected to the first current mirror, the second current mirror, and the first comparator circuit for adding the second current and the fourth current, and converting the sum of the second current and the fourth current into a voltage signal to generate the reference voltage signal; wherein... The reference voltage signal is the sum of the first reference voltage and the input voltage signal multiplied by a gain, and the gain product is determined by the voltage divider circuit and the multiplier relationship.

4. The power supply device as described in claim 1, wherein the temperature sensing circuit further comprises: A second metal-oxide-semiconductor transistor is disposed on the power switch. The second metal-oxide-semiconductor transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to the second reference voltage, and a source generating a second sense voltage signal. A second comparator circuit is electrically connected to the source of the second metal-oxide-semiconductor transistor to receive the second sense voltage signal, and electrically connected to the reference voltage generation circuit and the control circuit to compare the second sense voltage signal with the reference voltage signal to generate a second over-temperature protection signal, and output the second over-temperature protection signal to the control circuit. The control circuit adjusts the control signal according to the first over-temperature protection signal and the second over-temperature protection signal to regulate the operating temperature of the power switch. The first metal-oxide-semiconductor transistor and the second metal-oxide-semiconductor transistor are respectively disposed at different positions on the power switch; and the control circuit includes an OR gate for performing an OR operation on the first over-temperature protection signal and the second over-temperature protection signal, and adjusting the control signal according to the result of the OR operation.

5. The power supply device as claimed in claim 1, wherein the input voltage signal varies due to the channel length modulation effect of the power switch, and the reference voltage signal is used to compensate for the portion of the first sense voltage signal affected by the variation of the input voltage signal.

6. A method for temperature regulation in a power supply device, wherein a power switch in the power supply device is used to convert an input voltage signal into an output voltage signal according to a control signal, the temperature regulation method comprising: generating a reference voltage signal based on a first reference voltage and the input voltage signal; and disposing a first metal-oxide-semiconductor transistor on the power switch, wherein the first metal-oxide-semiconductor transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to a second reference voltage, and a source generating a first sensing voltage signal, wherein... The second reference voltage is a fixed value; and the first sense voltage signal is compared with the reference voltage signal to generate a first over-temperature protection signal, wherein the first over-temperature protection signal is used to adjust the control signal to regulate the operating temperature of the power switch.

7. The temperature regulation method as described in claim 6, wherein the power switch and the first metal-oxide-semiconductor transistor system are integrated in a multi-chip module (MCM) package architecture.

8. The temperature regulation method as described in claim 6, wherein generating the reference voltage signal comprises: dividing the input voltage signal to generate a voltage divider signal; converting the voltage divider signal into a first current; converting the first current into a second current, the first current being a multiple of the second current; converting the first reference voltage into a third current; converting the third current into a fourth current; and adding the second current and the fourth current, and converting the sum of the second current and the fourth current into a voltage signal to generate the reference voltage signal.

9. The temperature regulation method as described in claim 6, further comprising: disposing a second metal-oxide-semiconductor transistor on the power switch, wherein the second metal-oxide-semiconductor transistor includes a drain electrically connected to the input voltage signal, a gate electrically connected to the second reference voltage, and a source generating a second sense voltage signal; comparing the second sense voltage signal with the reference voltage signal to generate a second over-temperature protection signal; and performing an OR operation on the first over-temperature protection signal and the second over-temperature protection signal, and adjusting the control signal according to the result of the OR operation; wherein the first over-temperature protection signal and the second over-temperature protection signal are used to adjust the control signal to regulate the operating temperature of the power switch; and wherein the first metal-oxide-semiconductor transistor and the second metal-oxide-semiconductor transistor are respectively disposed at different positions on the power switch.

10. The temperature regulation method as described in claim 6, wherein the first sensing voltage signal has a positive temperature coefficient.

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