A power device, temperature sampling system and method

Abstract

A power device, a temperature sampling system and a method. The power device comprises a main control terminal, a start control terminal, a temperature sampling terminal, a drain terminal, a first source terminal and a second source terminal; a drain of a main switch tube is connected to the drain terminal, a source is connected to the first source terminal, and a gate is connected to the main control terminal to realize power conversion; a drain of a start switch tube is connected to the drain terminal, a source is connected to the second source terminal, and a gate is connected to the start control terminal to generate a start power supply; a resistance is connected between the drain terminal and the gate of the start switch tube; one end of a temperature detection element is connected to the temperature sampling terminal, and the other end is connected to the start control terminal or the main control terminal to generate a temperature detection signal of the power device. The power device, the temperature sampling system and the method of the application can complete temperature measurement by only adding a temperature sampling terminal, reduce the pin resource occupation of the power device, and avoid the interference of the switching noise of the main switch tube and the external coupling noise on the temperature sampling accuracy.

Description

Technical Field

[0001] This application relates to the field of power semiconductor technology, and in particular to a power device, a temperature sampling system and method. Background Technology

[0002] Existing Smart MOS devices integrate a main switch Q1, a sampling switch Q2, a start-up switch Q3, and a resistor R, such as... Figure 1 As shown, the main switch Q1 is the core device for power conversion. The sampling switch Q2 is mirror-matched with the main switch Q1 to achieve current sampling in the main circuit. The start-up switch Q3 provides initial power to the control circuit during the system power-on phase. A resistor R is connected between the gate of the start-up switch Q3 and the start-up control terminal, serving as the start-up resistor. During initial startup, the start-up switch Q3 conducts under the action of the start-up resistor to provide initial power to the control circuit. After startup, the control circuit outputs a PWM drive signal from the main control terminal to control the high-frequency switching of the main switch Q1 to complete power conversion. The sampling switch Q2 mirrors the current flowing through the main switch Q1 to achieve feedback and protection control.

[0003] To achieve over-temperature protection in Smart MOS, an additional temperature sensing device needs to be added to the existing Smart MOS for temperature detection. However, this approach has two inherent drawbacks: First, the added temperature sensing device requires multiple independent pins to output temperature measurement signals, thus consuming the chip's limited pin resources; second, the grounding connection structure of the temperature sensing element allows switching noise from the main power transistor and external electromagnetic noise to couple into the temperature sensing device, leading to deviations in the temperature readings and compromising measurement accuracy. Summary of the Invention

[0004] In order to solve at least one of the problems existing in the prior art, the purpose of this application is to provide a power device, a temperature sampling system and method, reduce the pin resource occupation of the power device, and avoid the interference of the switching noise of the main switch and external coupling noise on the temperature sampling accuracy.

[0005] To achieve the above objectives, this application provides a power device, comprising: Main control terminal, start control terminal, temperature sampling terminal, drain terminal, first source terminal, and second source terminal; The main switch transistor has its drain connected to the drain terminal, its source connected to the first source terminal, and its gate connected to the main control terminal to achieve power conversion. A start-up switch is configured, wherein the drain of the start-up switch is connected to the drain terminal, the source of the start-up switch is connected to the second source terminal, and the gate of the start-up switch is connected to the start-up control terminal to generate a start-up power supply. A resistor connected between the drain terminal and the gate of the power-on switch transistor; A temperature sensing element, one end of which is connected to the temperature sampling terminal and the other end of which is connected to the start control terminal or the main control terminal, is used to generate a temperature detection signal for the power device.

[0006] Furthermore, when the gate node connected to the temperature sensing element is in a low-level state, the temperature sampling terminal generates a temperature sensing signal output.

[0007] Furthermore, the temperature sensing element includes at least one diode, a thermistor, or a switching transistor in the form of a diode connection.

[0008] Furthermore, the temperature sensing element is a diode, with the anode of the diode connected to the temperature sampling terminal and the cathode connected to the start control terminal or the main control terminal. When the start control terminal or the main control terminal is at a low level, the temperature sampling terminal generates a temperature detection signal output.

[0009] Furthermore, it also includes: a sampling switch and a third source terminal; the drain of the sampling switch is connected to the drain terminal, the source of the sampling switch is connected to the third source terminal, and the gate of the sampling switch is connected to the main control terminal, forming a current mirror structure with the main switch to generate a sampling current.

[0010] To achieve the above objectives, this application also provides a temperature sampling system for a power device, including a power device and an over-temperature detection circuit, wherein, The power device is the power device described above; The over-temperature detection circuit is connected to the temperature sampling terminal and generates an over-temperature indication signal based on the temperature detection signal output by the temperature sampling terminal.

[0011] Furthermore, the over-temperature detection circuit includes a bias current source, a reference voltage generation circuit, and a comparator, wherein, The bias current source is connected to the temperature sampling terminal to provide bias current for the temperature sensing element; The reference voltage generating circuit outputs a reference voltage; The comparator receives the temperature detection signal and the reference voltage respectively, and outputs an over-temperature indication signal.

[0012] Furthermore, the reference voltage generating circuit and the temperature detection element are connected to the same control terminal; when the temperature detection element is connected to the start control terminal, the reference voltage generating circuit is connected to the start control terminal; when the temperature detection element is connected to the main control terminal, the reference voltage generating circuit is connected to the main control terminal.

[0013] Furthermore, the reference voltage generating circuit consists of a reference current source connected in series with two voltage divider resistors. The reference current source outputs a constant reference current to power the voltage divider resistors to generate a stable reference voltage.

[0014] To achieve the above objectives, this application also provides a temperature sampling method for a power device, applied to the temperature sampling system of the power device as described above, comprising the following steps: The temperature sensing element is used to generate a temperature sensing signal for the power device; The over-temperature detection circuit generates an over-temperature indication signal based on the temperature detection signal.

[0015] The power device, temperature sampling system, and method of this application can complete temperature measurement by adding only a single temperature sampling terminal ST. The original gate of the main switch and the gate node of the start-up switch are reused to build the temperature measurement path. There is no need to add an additional independent dedicated temperature measurement pin, which alleviates the problem of tight package pins of power devices and is conducive to device miniaturization and reducing packaging and PCB layout costs.

[0016] The power device, temperature sampling system, and method of this application abandon the traditional wiring method of grounding temperature sensing elements. The temperature sensing path is built based on the gate node, avoiding the power ground loop. It effectively isolates the coupling of high-frequency switching noise of the main power tube and external electromagnetic interference to the temperature sensing signal, eliminates temperature sensing voltage drift and protection threshold offset problems, avoids device false over-temperature protection or failure to protect against over-temperature, and improves the overall reliability of the machine.

[0017] The power device, temperature sampling system, and method of this application perform temperature measurement only when the multiplexed gate is in the low-level range: continuous temperature measurement is performed when the gate of the multiplexed startup switch is used; when the gate of the multiplexed main switch is used, sampling is performed only during the low-level window of the PWM, without interfering with the normal high-frequency power conversion of the main switch, thus balancing the temperature measurement function with the basic operating performance of the power supply system.

[0018] The power device, temperature sampling system, and method of this application only require adding a temperature detection element inside the chip, and a complete over-temperature protection can be achieved by using an external over-temperature detection circuit. The temperature detection element can be a conventional device such as a diode, thermistor, or transistor, which is easy to integrate, requires a small increase in chip area, and has controllable mass production costs.

[0019] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the present application and form part of the specification. Together with the embodiments of the present application, they serve to explain the present application but do not constitute a limitation thereof. In the drawings: Figure 1 The schematic diagram of an existing power device circuit; Figure 2 This is a schematic diagram of the power device circuit of Embodiment 1 of this application; Figure 3 This is a schematic diagram of the power device circuit in Embodiment 2 of this application; Figure 4 This is a schematic diagram of the power device circuit in Embodiment 3 of this application; Figure 5 This is a block diagram illustrating the principle of the temperature sampling system for the power device in Embodiment 4 of this application; Figure 6 This is a circuit diagram of the temperature sampling system for the power device in Embodiment 5 of this application; Figure 7 This is a circuit diagram of the temperature sampling system for the power device in Embodiment 6 of this application; Figure 8 This is a circuit diagram of the temperature sampling system for the power device in Embodiment 7 of this application. Detailed Implementation

[0021] To better understand and explain this application, a further detailed description will be provided below with reference to the accompanying drawings. This application is not limited to these specific embodiments. Rather, any modifications or equivalent substitutions made to this application should be covered within the scope of the claims.

[0022] It should be noted that many specific details are provided in the following embodiments. Those skilled in the art should understand that this application can be implemented without these specific details. In the various embodiments given below, principles, structures, and components well known in the art are not described in detail in order to highlight the main points of this application.

[0023] It should be understood that although terms such as "first," "second," etc., may be used herein to describe various units or data, these units or data should not be limited by these terms. These terms are used merely to distinguish one feature from another. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.

[0024] It should be understood that the power devices in this application are not limited to Smart MOS devices. As long as the device contains a power switching transistor, the technical concept of this application can be adopted: setting a temperature sampling terminal, multiplexing the temperature sensing element and the reference voltage generation circuit using the same gate control node to complete device temperature sampling, achieving temperature detection with fewer pins and noise immunity. Those skilled in the art can make adaptive modifications based on the level characteristics of different devices to achieve the same technical effects as this invention.

[0025] Terminology Explanation: Smart MOS (Intelligent Power MOSFET) is an integrated power device specifically designed for switching power supplies / power semiconductors, distinct from purely discrete ordinary MOSFETs. It integrates the main power switch, a matching auxiliary MOSFET, and passive components within a single chip, achieving integrated power conversion, current sampling, and power-on self-powering. Combined with an external PWM control circuit, it can form a complete switching power supply power stage, widely used in consumer electronics applications such as fast charging adapters, DC-DC buck power supplies, and low-power offline power supplies. Smart MOS pinouts include: G: Main control terminal (gate of main switch Q1); SG: Start-up control terminal (starts up the gate of switch Q3); ST: Temperature sampling terminal (a new pin added in this invention); S: First source extreme; SS: Second source extreme; SE: Third source extreme; D: Leakage to the extreme.

[0026] This application provides a power device and a temperature sampling system, wherein the power device includes: Main control terminal, start control terminal, temperature sampling terminal, drain terminal, first source terminal, and second source terminal; The main switch transistor has its drain connected to the drain terminal, its source connected to the first source terminal, and its gate connected to the main control terminal to achieve power conversion. A start-up switch is configured, wherein the drain of the start-up switch is connected to the drain terminal, the source of the start-up switch is connected to the second source terminal, and the gate of the start-up switch is connected to the start-up control terminal to generate a start-up power supply. A resistor connected between the drain terminal and the gate of the power-on switch transistor; A temperature sensing element, one end of which is connected to the temperature sampling terminal and the other end of which is connected to the start control terminal or the main control terminal, is used to generate a temperature detection signal for the power device.

[0027] Figure 2This is a schematic diagram of the power device circuit in Embodiment 1 of this application, as shown below. Figure 2 As shown, the power device 10 of Embodiment 1 of this application includes: a main switch transistor Q1, a start-up switch transistor Q3, a resistor R, and a temperature detection element.

[0028] The power device 10 has the following pins: main control terminal G, start control terminal SG, temperature sampling terminal ST, drain terminal D, first source terminal S, and second source terminal SS.

[0029] The drain of the main switch Q1 is connected to the drain terminal D, the source of the main switch is connected to the first source terminal S, and the gate of the main switch is connected to the main control terminal G to achieve power conversion.

[0030] The drain of the start-up switch Q3 is connected to the drain terminal D, the source of the start-up switch Q3 is connected to the second source terminal SS, and the gate of the start-up switch is connected to the start-up control terminal SG to generate a start-up power supply.

[0031] Resistor R is connected between the drain terminal D and the gate of the start-up switch Q3.

[0032] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG or the main control terminal G, which is used to generate a temperature detection signal for the power device.

[0033] In Embodiment 1 of this application, the start-up control terminal SG is connected to the gate node of the start-up switch Q3, and the main control terminal G is connected to the gate node of the main switch Q1. One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is selectively connected to either the start-up control terminal SG or the main control terminal G, thereby multiplexing the gate node of the start-up switch Q3 or the gate node of the main switch Q1 to form a temperature measurement path. When the gate node of the start-up switch Q3 or the gate node of the main switch Q1 multiplexed by the temperature sensing element is in a low-level state, the temperature sampling terminal ST generates a temperature detection signal V. ST Output.

[0034] For example, Figure 2 One end of the temperature sensing element of the power device 10 on the left is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG. The gate node of the start switch Q3 is used to form a temperature measurement path.

[0035] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0036] When the external control circuit is working normally, the start control terminal SG remains at a low level, and the start switch Q3 remains off, reducing the static power consumption of the system.

[0037] During steady-state operation of the system, the start-up control terminal SG remains at a low level, ensuring continuous conduction of the temperature measurement path and forming a temperature measurement current loop from the temperature sampling terminal ST, the temperature sensing element, to the start-up control terminal SG. The temperature sensing element can acquire the temperature of the power devices in real time and output a temperature detection signal V that varies with the temperature. ST .

[0038] The temperature sensing element forms a temperature measurement path by reusing the gate node of the start-up switch Q3. Only the temperature sampling terminal ST needs to be added to realize the temperature acquisition of the power device. No additional device pins are required, and the switching noise interference caused by traditional grounding temperature measurement is avoided.

[0039] For example, Figure 2 In the power device on the right, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G. The gate node of the main switch Q1 is used to form a temperature measurement path.

[0040] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0041] During normal power conversion, the external control circuit inputs a high-frequency PWM drive signal through the main control terminal G to control the main switch Q1 to periodically turn on and off, thereby achieving power conversion. Only when the PWM signal at the main control terminal G is in the low-level range, the potential of the main control terminal G is low, the temperature measurement path meets the conduction condition, and temperature sampling can be completed normally; when the PWM signal is high, the potential of the main control terminal G rises, the temperature measurement path is disconnected, and the temperature of the power device cannot be collected temporarily.

[0042] When each PWM signal is low, the temperature sampling pin ST, the temperature sensing element, and the main control pin G form a complete temperature measurement loop. The temperature sensing element acquires the temperature of the power device and outputs a temperature detection signal. .

[0043] The temperature sensing element forms a temperature measurement path by reusing the gate node of the main switch Q1. Temperature acquisition can be achieved by simply adding a temperature sampling terminal ST, without the need to add additional device pins, while avoiding the switching noise interference caused by traditional grounding temperature measurement.

[0044] Figure 3 The circuit schematic of the power device in Embodiment 2 of this application is shown below. Figure 3 As shown, the power device in Embodiment 2 of this application differs from that in Embodiment 1 in that it uses a diode VD as a temperature sensing element. The anode of the diode VD is connected to the temperature sampling terminal ST, and the cathode of the diode VD is connected to the start-up control terminal SG or the main control terminal G, thus forming a temperature measurement circuit.

[0045] In this embodiment, a diode VD is used as a temperature sensing element connected between the temperature sampling terminal ST and the start-up control terminal SG or the main control terminal G. Utilizing the temperature-dependent characteristics of the PN junction voltage drop, the internal temperature of the power device is converted into a voltage signal, enabling temperature sensing and acquisition. This structure can reduce interference caused by ground potential fluctuations and utilizes the reference voltage of the main control terminal G or the start-up control terminal SG for temperature measurement, thus improving measurement accuracy.

[0046] Preferably, the temperature sensing element is at least one diode, but it can also be multiple diodes connected in series or in parallel.

[0047] Multiple diodes connected in forward configuration are used as the temperature sensing element. The total forward voltage drop is the sum of the voltage drops of each diode, amplifying the voltage change corresponding to temperature, increasing the voltage swing of the temperature signal, and increasing V. ST By varying the temperature range, the temperature measurement resolution is improved, the difficulty for the comparison circuit to identify the signal is reduced, and the temperature measurement sensitivity is enhanced.

[0048] Using multiple diodes connected in forward parallel as temperature sensing elements, the total current is distributed among the diodes, reducing the current density flowing through a single diode and improving device reliability. At the same time, it has a certain averaging effect on the process deviation of a single diode, weakening the temperature measurement error caused by the individual process discreteness of a single diode and improving batch consistency.

[0049] Preferably, the temperature sensing element is at least one thermistor or diode-connected switching transistor. The thermistor or diode-connected switching transistor is connected across the start-up control terminal SG or the main control terminal G. The diode-connected switching transistor forms an equivalent diode as the temperature sensing element, relying on the negative temperature coefficient of the PN junction forward voltage to achieve temperature acquisition, enabling more accurate acquisition of the internal temperature of the power device.

[0050] Figure 4 This is a schematic diagram of the power device circuit in Embodiment 3 of this application, as shown below. Figure 4 As shown, the power device of Embodiment 3 of this application includes: a main switch Q1, a sampling switch Q2, a start-up switch Q3, a resistor R, and a temperature detection element.

[0051] The power device 10 has the following pins: main control terminal G, start control terminal SG, temperature sampling terminal ST, drain terminal D, first source terminal S, second source terminal SS, and third source terminal SE.

[0052] The drain of the main switch Q1 is connected to the drain terminal D, the source of the main switch is connected to the first source terminal S, and the gate of the main switch is connected to the main control terminal G to achieve power conversion.

[0053] The drain of sampling switch Q2 is connected to the drain terminal D, the source of sampling switch Q2 is connected to the third source terminal SE, and the gate of sampling switch Q2 is connected to the main control terminal G. Together with the main switch Q1, they form a current mirror structure to generate a sampling current signal.

[0054] The drain of the start-up switch Q3 is connected to the drain terminal D, the source of the start-up switch is connected to the second source terminal SS, and the gate of the start-up switch is connected to the start-up control terminal SG to generate a start-up power supply.

[0055] Resistor R is connected between the drain terminal D and the gate of the start-up switch Q3.

[0056] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG or the main control terminal G. In this way, the gate node of the start switch Q3 or the gate node of the main switch Q1 is reused to form a temperature measurement path to realize the temperature acquisition of the power device.

[0057] For example, Figure 4 In the power device on the left, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG. The gate node of the start switch Q3 is reused to construct the temperature measurement path.

[0058] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0059] When the external control circuit is working normally, the start control terminal SG remains at a low level, and the start switch Q3 remains off, reducing the static power consumption of the system.

[0060] During steady-state operation, the start-up control terminal SG remains at a low level, ensuring continuous conduction of the temperature measurement path. This forms a temperature measurement current loop from the temperature sampling terminal ST, the temperature sensing element, to the start-up control terminal SG. The temperature sensing element can acquire the internal temperature of the power device in real time and output a temperature detection signal that varies with the temperature. .

[0061] The sampling switch Q2 mirrors the main power current of the main switch Q1 and outputs a sampling current signal to the outside through the third source terminal SE. The external circuit obtains the magnitude of the main circuit current based on the sampling current signal of the third source terminal SE, which is used for overcurrent detection and overcurrent protection of power devices.

[0062] The temperature sensing element forms a temperature measurement path by reusing the gate node of the start-up switch Q3. Only the temperature sampling terminal ST needs to be added to realize the temperature acquisition of the power device. No additional device pins are required, and the switching noise interference caused by traditional grounding temperature measurement is avoided.

[0063] For example, Figure 4 In the power device on the right, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G. The gate node of the main switch Q1 is reused to construct the temperature measurement path.

[0064] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0065] During the normal power conversion phase of the system, the external control circuit inputs a high-frequency PWM drive signal through the main control terminal G to control the main switch Q1 to periodically turn on and off, thereby realizing power conversion. Only when the PWM signal at the main control terminal G is in the low-level range, the potential of the main control terminal G is low, the temperature measurement path meets the conduction condition, and temperature acquisition can be completed normally; when the PWM signal is high, the potential of the main control terminal G rises, the temperature measurement path is disconnected, and temperature acquisition is temporarily impossible.

[0066] When each PWM signal is low, the temperature sampling pin ST, the temperature sensing element, and the main control pin G form a complete temperature measurement loop. The temperature sensing element acquires the temperature of the power device and outputs a temperature detection signal. .

[0067] The sampling switch Q2 mirrors the main power current of the main switch Q1 and outputs a sampling current signal to the outside through the third source terminal SE. The external circuit obtains the magnitude of the main circuit current based on the sampling current signal of the third source terminal SE, which is used for overcurrent detection and overcurrent protection of power devices.

[0068] The temperature sensing element forms a temperature measurement path by reusing the gate node of the main switch Q1. Only the temperature sampling terminal ST needs to be added to realize the temperature acquisition of the power device. There is no need to add additional device pins, and the switching noise interference caused by traditional grounding temperature measurement is avoided.

[0069] Figure 5 This is a block diagram illustrating the principle of the temperature sampling system for the power device in Embodiment 4 of this application. Figure 5 As shown, the temperature sampling system for the power device in Embodiment 4 of this application includes a power device 10 and an over-temperature detection circuit 20, wherein, The power device 10 integrates a main switch Q1, a start-up switch Q3, a resistor R, and a temperature sensing element. The power device 10 has the following pinouts: main control terminal G, start-up control terminal SG, temperature sampling terminal ST, drain terminal D, first source terminal S, and second source terminal SS.

[0070] The drain of the main switch Q1 is connected to the drain terminal D, the source of the main switch is connected to the first source terminal S, and the gate of the main switch is connected to the main control terminal G to achieve power conversion.

[0071] The drain of the start-up switch Q3 is connected to the drain terminal D, the source of the start-up switch is connected to the second source terminal SS, and the gate of the start-up switch is connected to the start-up control terminal SG to generate a start-up power supply.

[0072] Resistor R is connected between the drain terminal D and the gate of the start-up switch Q3.

[0073] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end can be connected to the start control terminal SG or the main control terminal G. In this way, the gate node of the start switch Q3 or the gate node of the main switch Q1 are reused to form a temperature measurement path to generate a temperature detection signal for the power device.

[0074] The over-temperature detection circuit 20 is located outside the power device 10. The over-temperature detection circuit 20 is connected to the temperature sampling terminal ST and outputs an over-temperature indication signal MOS_OTP for the external control circuit to perform over-temperature protection.

[0075] The over-temperature detection circuit 20 provides a drive bias current to the temperature detection element through the temperature sampling terminal ST, and acquires a temperature detection signal related to the temperature of the power device 10 from the temperature sampling terminal ST. And based on the temperature detection signal Determine if the device temperature exceeds the limit, and generate the corresponding over-temperature indication signal MOS_OTP for the external control circuit to perform over-temperature protection.

[0076] For example, such as Figure 5 In the system (a) shown, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG. The gate node of the start switch Q3 is reused to construct the temperature measurement path.

[0077] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0078] When the external control circuit is working normally, the start control terminal SG remains at a low level, and the start switch Q3 remains off, reducing the static power consumption of the system.

[0079] During steady-state operation, the start-up control terminal SG remains at a low level, ensuring continuous conduction of the temperature measurement path and forming a temperature measurement current loop from the temperature sampling terminal ST, the temperature sensing element, to the start-up control terminal SG. The temperature sensing element can acquire the internal temperature of the power device in real time and output a temperature detection signal that varies with the temperature. .

[0080] The temperature sensing element forms a temperature measurement path by reusing the gate node of the start-up switch Q3. Only the temperature sampling terminal ST needs to be added to realize the temperature acquisition of the power device. No additional device pins are required, and the switching noise interference caused by traditional grounding temperature measurement is avoided.

[0081] The over-temperature detection circuit 20 provides a drive bias current to the temperature detection element through the temperature sampling terminal ST, and adjusts the current based on the real-time temperature detection signal. Determine if the device temperature exceeds the limit, and generate the corresponding over-temperature indication signal MOS_OTP for the external control circuit to perform over-temperature protection.

[0082] For example, such as Figure 5 In the system (b) shown, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G. The gate node of the main switch Q1 is reused to construct the temperature measurement path.

[0083] During the initial power-on phase, the external control circuit sets the start control terminal SG to a high level, controls the start switch Q3 to conduct through the resistor R, and supplies power to the external control circuit through the high voltage self-drain terminal D, thus completing the system startup.

[0084] During the normal power conversion phase of the system, the external control circuit inputs a high-frequency PWM drive signal through the main control terminal G to control the main switch Q1 to periodically turn on and off, thereby realizing power conversion. Only when the PWM signal at the main control terminal G is in the low-level range, the potential of the main control terminal G is low, the temperature measurement path meets the conduction condition, and temperature acquisition can be completed normally; when the PWM signal is high, the potential of the main control terminal G rises, the temperature measurement path is disconnected, and temperature acquisition is temporarily impossible.

[0085] When each PWM signal is low, the temperature sampling pin ST, the temperature sensing element, and the main control pin G form a complete temperature measurement loop. The temperature sensing element acquires the temperature of the power device and outputs a temperature detection signal. .

[0086] The over-temperature detection circuit 20 provides a drive bias current to the temperature detection element through the temperature sampling terminal ST, and collects the temperature detection signal at each low level of the PWM signal. Determine if the device temperature exceeds the limit, and generate the corresponding over-temperature indication signal MOS_OTP for the external control circuit to perform over-temperature protection.

[0087] Preferably, in Embodiment 4 of this application, the temperature sensing element is a diode, a thermistor, or a diode-connected switching transistor. The diode-connected switching transistor, by shorting the base and collector of the transistor, utilizes the emitter junction (PN junction) to form an equivalent diode as the temperature sensing element. It relies on the negative temperature coefficient of the emitter junction's forward voltage to achieve temperature acquisition, enabling more accurate acquisition of the internal temperature of the power device.

[0088] Preferably, in Embodiment 4 of this application, the temperature sensing element is at least one diode, or it can be multiple diodes connected in series or in parallel.

[0089] like Figure 5 In the systems (c) and (d) shown, a single diode is used as the temperature sensing element. By utilizing the negative temperature coefficient of the forward voltage of the PN junction, the temperature change causes a change in the forward voltage drop, which converts the internal temperature of the power device into a voltage signal, thereby realizing temperature sensing and completing temperature sampling.

[0090] Multiple diodes connected in forward bias are used as the temperature sensing element. The total forward voltage drop is the sum of the voltage drops of each diode, amplifying the voltage change corresponding to temperature, increasing the voltage swing of the temperature signal, and thus increasing the temperature sensing signal. By varying the temperature range, the temperature measurement resolution is improved, the difficulty for the comparison circuit to identify the signal is reduced, and the temperature measurement sensitivity is enhanced.

[0091] Using multiple diodes connected in forward parallel as temperature sensing elements, the total current is distributed among the diodes, reducing the current density flowing through a single diode and improving device reliability. At the same time, it has a certain averaging effect on the process deviation of a single diode, weakening the temperature measurement error caused by the individual process discreteness of a single diode and improving batch consistency.

[0092] Preferably, in embodiment 4 of this application, the power device 10 further includes: a sampling switch Q2 and a third source terminal SE. The drain of the sampling switch Q2 is connected to the drain terminal D, the source of the sampling switch Q2 is connected to the third source terminal SE, and the gate of the sampling switch Q2 is connected to the main control terminal G, forming a current mirror structure with the main switch Q1 to generate a sampling current signal; the external circuit obtains the magnitude of the main circuit current based on the sampling current signal of the third source terminal SE, which is used for overcurrent detection and overcurrent protection of the power device.

[0093] Figure 6 This is a circuit schematic diagram of the temperature sampling system for the power device in Embodiment 5 of this application, as shown below. Figure 6 As shown, the temperature sampling system for the power device in Embodiment 5 of this application includes: a power device 10 and an over-temperature detection circuit 20, wherein, The power device 10 is the same as in Embodiment 4 above.

[0094] The over-temperature detection circuit 20 is located outside the power device 10. The over-temperature detection circuit 20 includes a bias current source IBIAS, a reference voltage generation circuit, and a comparator CMP.

[0095] Bias current source I BIAS The temperature sampling terminal ST of the power device 10 is connected to provide a constant bias current for the temperature sensing element.

[0096] Temperature detection signal output from temperature sampling terminal ST and the reference voltage output by the reference voltage generation circuit The two input terminals of the comparator CMP are connected to the comparator CMP respectively. The output terminal of the comparator CMP outputs an over-temperature indication signal MOS_OTP, which is sent to the external main control circuit.

[0097] For example, Figure 5 In the system on the left, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG. The gate node of the start switch Q3 is reused to construct the temperature measurement path.

[0098] During the initial power-on phase, before the external control circuit has established a power supply, the start-up switch Q3 is turned on by the resistor R, and the high-voltage self-draining terminal D supplies power to the external control circuit through the start-up switch Q3 to complete the system startup.

[0099] When the external control circuit is working normally, the start control terminal SG remains at a low level, and the start switch Q3 remains off, reducing the static power consumption of the system.

[0100] During steady-state operation of the system, the start-up control terminal SG remains at a low level, ensuring continuous conduction of the temperature measurement path. The over-temperature detection circuit 20 provides bias to the temperature sensing element via the temperature sampling terminal ST, forming a temperature measurement current loop from the over-temperature detection circuit 20, the temperature sampling terminal ST, the temperature sensing element, to the start-up control terminal SG. The temperature sensing element can sense the internal temperature of the power device in real time and output a temperature detection signal that changes with the temperature. Provide the over-temperature detection circuit 20.

[0101] The reference voltage output by the internal reference voltage generation circuit of the temperature detection circuit 20 and the temperature detection signal output by the temperature sampling terminal ST The temperature detection signal is fed into the two input terminals of the comparator CMP respectively. The comparator CMP will convert the temperature detection signal into a signal. With reference voltage Perform real-time comparison and output the over-temperature indication signal MOS_OTP.

[0102] When the internal temperature of power device 10 is lower than the preset over-temperature threshold, the temperature detection signal is output in real time by the temperature sampling terminal ST. Greater than the reference voltage The comparator CMP outputs a high level; when the internal temperature of power device 10 exceeds the preset over-temperature threshold, the temperature detection signal output by the temperature sampling terminal ST is activated. Reduced to below the reference voltage When the comparator CMP flips to output a low level, it generates a valid over-temperature indication signal MOS_OTP. Upon receiving the MOS_OTP signal, the external control circuit performs an over-temperature protection action.

[0103] For example, Figure 5 In the system on the right, one end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G. The gate node of the main switch Q1 is reused to construct the temperature measurement path.

[0104] During the initial power-on phase, before the external control circuit has established a power supply, the start-up switch Q3 is turned on by the resistor R, and the high-voltage self-draining terminal D supplies power to the external control circuit through the start-up switch Q3 to complete the system startup.

[0105] During the normal power conversion phase of the system, the external control circuit inputs a high-frequency PWM drive signal through the main control terminal G to control the main switch Q1 to periodically turn on and off, thereby realizing power conversion. Only when the PWM signal at the main control terminal G is in the low-level range, the potential of the main control terminal G is low, the temperature measurement path meets the conduction condition, and temperature sampling can be completed normally; when the PWM signal is high, the potential of the main control terminal G rises, the temperature measurement path is disconnected, and temperature cannot be collected temporarily.

[0106] When each PWM signal is low, the over-temperature detection circuit 20 forms a complete temperature measurement loop through the temperature sampling terminal ST pin, the temperature sensing element, and the main control terminal G. The temperature sensing element collects the internal temperature of the power device and outputs a temperature detection signal. Provide the over-temperature detection circuit 20.

[0107] The output reference voltage of the internal reference voltage generation circuit of the temperature detection circuit 20 and the temperature detection signal output by the temperature sampling terminal ST The temperature detection signal is fed into the two input terminals of the comparator CMP respectively. The comparator CMP will convert the temperature detection signal into a signal. With reference voltage Perform real-time comparison and output the over-temperature indication signal MOS_OTP.

[0108] When the PWM signal is low and the internal temperature of power device 10 is lower than the preset over-temperature threshold, the temperature detection signal output by the temperature sampling terminal ST is... Greater than the reference voltage The comparator outputs a high level; when the internal temperature of power device 10 exceeds the preset over-temperature threshold, the temperature detection signal output by the temperature sampling terminal ST is activated. Reduced to below the reference voltage When the comparator CMP flips to output a low level, it generates a valid over-temperature indication signal MOS_OTP. Upon receiving the MOS_OTP signal, the external control circuit performs an over-temperature protection action.

[0109] In Embodiment 5 of this application, the two input terminals of the comparator CMP of the over-temperature detection circuit 20 respectively receive temperature detection signals from the temperature sampling terminal ST of the power device 10. and the reference voltage from the output of the reference voltage generation circuit And compare the temperature detection signals in real time. and reference voltage Based on the comparison result, the over-temperature indication signal MOS_OTP is output, realizing the over-temperature indication of power device 10.

[0110] Figure 7 This is a circuit schematic diagram of the temperature sampling system for the power device in Embodiment 6 of this application, as shown below. Figure 7 As shown, the temperature sampling system for the power device in Embodiment 6 of this application includes a power device 10 and an over-temperature detection circuit 20, wherein, The power device 10 is the same as in Embodiment 4 above.

[0111] The over-temperature detection circuit 20 is located outside the power device 10. The over-temperature detection circuit 20 includes a bias current source IBIAS, a reference voltage generation circuit, and a comparator CMP.

[0112] Bias current source The temperature sampling terminal ST of the power device 10 is connected to provide a constant bias current for the temperature sensing element.

[0113] The reference voltage generation circuit and temperature detection element can be selectively connected to the start control terminal SG or the main control terminal G, respectively.

[0114] Temperature detection signal output from temperature sampling terminal ST and the reference voltage output by the reference voltage generation circuit The two input terminals of the comparator CMP are connected to the comparator CMP respectively. The output terminal of the comparator CMP outputs an over-temperature indication signal MOS_OTP, which is sent to the external main control circuit.

[0115] For example, Figure 7 In the system on the left, the temperature sensing element is connected to the start control terminal SG, and the reference voltage generation circuit is also connected to the start control terminal SG.

[0116] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start-up control terminal SG. A reference voltage generation circuit is connected to the start-up control terminal SG, using the potential of the start-up control terminal SG as a reference to generate a reference voltage. .

[0117] During the power-on phase, before the external control circuit is powered, the start-up switch Q3 is turned on by resistor R. The high-voltage self-drain terminal D supplies power to the external control circuit through the start-up switch Q3, completing the system startup. After the system stabilizes, SG remains low, and the start-up control terminal SG is turned off to reduce power consumption. In steady state, the start-up control terminal SG remains at a low potential, and the temperature measurement path remains open.

[0118] Bias current source A temperature measurement loop is formed from the temperature sampling terminal ST, the temperature detection element, and the start control terminal SG to obtain the temperature detection signal. At room temperature The comparator outputs a high level; when the device heats up to the over-temperature threshold, The comparator level flips to output an over-temperature indication signal MOS_OTP, triggering overheat protection.

[0119] In Embodiment 6 of this application, the temperature detection element and the reference voltage generation circuit are both connected to the start control terminal SG. The two share the SG node as the potential reference point, which can eliminate the level offset caused by the inconsistency of the reference potential and improve the accuracy of the over-temperature detection threshold. At the same time, the working timing of the reference voltage generation circuit is synchronized with the temperature measurement path, which can also reduce the interference of externally introduced switching noise.

[0120] For example, Figure 7 In the system on the right, the temperature sensing element is connected to the main control terminal G, and the reference voltage generation circuit is also connected to the main control terminal G.

[0121] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G, forming a temperature measurement loop. The voltage divider resistor below the reference voltage generation circuit is connected to the main control terminal G, using the potential of the main control terminal G as a reference to generate the reference voltage. .

[0122] During operation, the main control terminal G outputs a high-frequency PWM signal to drive the main switch Q1; the temperature measurement circuit is turned on only when the PWM signal is in the low level range, and the temperature detection element collects the internal temperature of the power device; the temperature measurement circuit is turned off when the PWM signal is in the high level range.

[0123] When the PWM signal is in the low-level range, the temperature sensing element generates a temperature sensing signal. And fed into the comparator and reference voltage A threshold comparison is performed. When the internal temperature of power device 10 is lower than the preset over-temperature threshold, the temperature detection signal... Greater than the reference voltage The comparator outputs a high level; when the internal temperature of power device 10 exceeds the preset over-temperature threshold, the temperature detection signal... Reduced to below the reference voltage The comparator CMP flips the output level, generating a valid over-temperature indication signal MOS_OTP. Upon receiving the MOS_OTP signal, the external control circuit executes the over-temperature protection action.

[0124] In Embodiment 6 of this application, the temperature detection element and the reference voltage generation circuit are both connected to the main control terminal G. They share the G node as the potential reference point to eliminate the level offset caused by different reference potentials and ensure the accuracy of the over-temperature comparison threshold. The reference voltage generation circuit is synchronized with the temperature measurement path according to the G node level and only works when G is at a low level to reduce external noise interference.

[0125] Figure 8 This is a circuit schematic diagram of the temperature sampling system for the power device in Embodiment 7 of this application, as shown below. Figure 8 As shown, the temperature sampling system for the power device in Embodiment 7 of this application includes a power device 10 and an over-temperature detection circuit 20, wherein, The power device 10 is the same as in Embodiment 4 above.

[0126] The over-temperature detection circuit 20 is located outside the power device 10. The over-temperature detection circuit 20 includes a bias current source IBIAS, a reference voltage generation circuit, and a comparator CMP.

[0127] Bias current source The temperature sampling terminal ST of the power device 10 is connected to provide a constant bias current for the temperature sensing element.

[0128] The reference voltage generation circuit consists of a reference current source. It consists of two voltage divider resistors connected in series, with the upper voltage divider resistor connected to a reference current source. The voltage divider resistors below can be connected to either the start-up control terminal SG or the main control terminal G. The connection point between the two voltage divider resistors outputs a reference voltage. .

[0129] Preferably, the voltage divider resistor and temperature sensing element below the reference voltage generation circuit can be selectively connected to the start control terminal SG or the main control terminal G, respectively.

[0130] Temperature detection signal output from temperature sampling terminal ST and the reference voltage output by the reference voltage generation circuit The two input terminals of the comparator CMP are connected to the comparator CMP respectively. The output terminal of the comparator CMP outputs an over-temperature indication signal MOS_OTP, which is sent to the external main control circuit.

[0131] For example, Figure 8In the system on the left, the temperature sensing element reuses the start-up control terminal SG, and the voltage divider resistor below the reference voltage generation circuit is connected to the start-up control terminal SG.

[0132] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the start control terminal SG, forming a temperature measurement loop; the voltage divider resistor below the reference voltage generation circuit is connected to the start control terminal SG, and the reference voltage is generated using the potential of the start control terminal SG as the voltage divider reference. .

[0133] During the power-on phase, the start control terminal SG outputs a high level to turn on the start switch Q3, which supplies power to the peripheral circuits.

[0134] After the system stabilizes, the start-up control terminal SG remains low, and the start-up switch Q3 is turned off to reduce static power consumption. Under steady-state conditions, the start-up control terminal SG remains at a low potential, and the temperature measurement path remains conductive.

[0135] Bias current source A temperature measurement loop is formed from the temperature sampling terminal ST, the temperature detection element, and the start control terminal SG. A temperature detection signal is generated in real time at the temperature sampling terminal ST. At room temperature The comparator outputs a high level; when the device heats up to the over-temperature threshold, The comparator level flips to output an over-temperature indication signal MOS_OTP, triggering overheat protection.

[0136] In Embodiment 7 of this application, the temperature detection element is connected to the start-up control terminal SG, and the upper voltage divider resistor of the reference voltage generation circuit is connected to the reference current source. The voltage divider resistor below is connected to the start-up control terminal SG, which can eliminate potential offset. The reference voltage automatically matches the temperature measurement sequence according to the SG level, suppressing external noise interference; with the help of a reference current source... It provides a stable bias, ensuring a stable reference voltage output, and the circuit is simple and requires no additional component pins.

[0137] For example, Figure 8 In the system on the right, the temperature detection element reuses the main control terminal G, and the reference voltage generation circuit is connected to the main control terminal G.

[0138] One end of the temperature sensing element is connected to the temperature sampling terminal ST, and the other end is connected to the main control terminal G, forming a temperature measurement loop. The voltage divider resistor below the reference voltage generation circuit is connected to the main control terminal G, using the potential of the main control terminal G as a reference to generate the reference voltage. .

[0139] During operation, the main control terminal G outputs a high-frequency PWM signal to drive the main switch Q1; the temperature measurement circuit is turned on only when the PWM signal is in the low level range, and the temperature detection element collects the internal temperature of the power device; the temperature measurement circuit is turned off when the PWM signal is in the high level range.

[0140] When the PWM signal is in the low-level range, the temperature sensing element generates a temperature sensing signal. And fed into the comparator and reference voltage A threshold comparison is performed. When the internal temperature of power device 10 is lower than the preset over-temperature threshold, the temperature detection signal... Greater than the reference voltage The comparator outputs a high level; when the internal temperature of power device 10 exceeds the preset over-temperature threshold, the temperature detection signal... Reduced to below the reference voltage The comparator CMP flips the output level, generating a valid over-temperature indication signal MOS_OTP. Upon receiving the MOS_OTP signal, the external control circuit executes the over-temperature protection action.

[0141] In Embodiment 7 of this application, the temperature sensing element is connected to the main control terminal G, and the upper voltage divider resistor of the reference voltage generation circuit is connected to the reference current source. The voltage divider resistor below is connected to the main control terminal G, which can eliminate potential offset. The reference voltage automatically matches the temperature measurement timing with the level of G, suppressing noise interference. Achieve stability The circuit is simple and requires no additional component pins.

[0142] This application also provides a temperature sampling method for a power device, applied to the temperature sampling system of the aforementioned power device, comprising the following steps: Temperature sensing elements are used to generate temperature sensing signals for power devices; The over-temperature detection circuit generates an over-temperature indication signal based on the temperature detection signal.

[0143] It will be understood by those skilled in the art that the above are merely preferred embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A power device, characterized in that, include: Main control terminal, start control terminal, temperature sampling terminal, drain terminal, first source terminal, and second source terminal; The main switch transistor has its drain connected to the drain terminal, its source connected to the first source terminal, and its gate connected to the main control terminal to achieve power conversion. A start-up switch is configured, wherein the drain of the start-up switch is connected to the drain terminal, the source of the start-up switch is connected to the second source terminal, and the gate of the start-up switch is connected to the start-up control terminal to generate a start-up power supply. A resistor connected between the drain terminal and the gate of the power-on switch transistor; A temperature sensing element, one end of which is connected to the temperature sampling terminal and the other end of which is connected to the start control terminal or the main control terminal, is used to generate a temperature detection signal for the power device.

2. The power device according to claim 1, characterized in that, When the gate node to which the temperature sensing element is connected is in a low-level state, the temperature sampling terminal generates a temperature sensing signal output.

3. The power device according to claim 1 or 2, characterized in that, The temperature sensing element includes at least one diode, a thermistor, or a switching transistor in the form of a diode connection.

4. The power device according to claim 1 or 2, characterized in that, The temperature sensing element is a diode. The anode of the diode is connected to the temperature sampling terminal, and the cathode is connected to the start control terminal or the main control terminal. When the start control terminal or the main control terminal is at a low level, the temperature sampling terminal generates a temperature detection signal output.

5. The power device according to claim 1 or 2, characterized in that, Also includes: The sampling switch transistor has a third source terminal; the drain of the sampling switch transistor is connected to the drain terminal, the source of the sampling switch transistor is connected to the third source terminal, and the gate of the sampling switch transistor is connected to the main control terminal, forming a current mirror structure with the main switch transistor to generate a sampling current.

6. A temperature sampling system for a power device, comprising a power device and an over-temperature detection circuit, characterized in that, The power device is the power device according to any one of claims 1 to 5; The over-temperature detection circuit is connected to the temperature sampling terminal and generates an over-temperature indication signal based on the temperature detection signal output by the temperature sampling terminal.

7. The temperature sampling system for power devices according to claim 6, characterized in that, The over-temperature detection circuit includes a bias current source, a reference voltage generation circuit, and a comparator, wherein... The bias current source is connected to the temperature sampling terminal to provide bias current for the temperature sensing element; The reference voltage generating circuit outputs a reference voltage; The comparator receives the temperature detection signal and the reference voltage respectively, and outputs an over-temperature indication signal.

8. The temperature sampling system for power devices according to claim 7, characterized in that, The reference voltage generating circuit and the temperature detection element are connected to the same control terminal; when the temperature detection element is connected to the start control terminal, the reference voltage generating circuit is connected to the start control terminal; when the temperature detection element is connected to the main control terminal, the reference voltage generating circuit is connected to the main control terminal.

9. The temperature sampling system for power devices according to claim 8, characterized in that, The reference voltage generating circuit consists of a reference current source connected in series with two voltage divider resistors. The reference current source outputs a constant reference current to power the voltage divider resistors to generate a stable reference voltage.

10. A temperature sampling method for a power device, applied to the temperature sampling system of the power device according to any one of claims 6 to 9, characterized in that, Includes the following steps: The temperature sensing element is used to generate a temperature sensing signal for the power device; The over-temperature detection circuit generates an over-temperature indication signal based on the temperature detection signal.

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