An over-temperature protection circuit with rising and falling thresholds

Abstract

The present invention relates to an over-temperature protection circuit with rising and falling thresholds. The circuit includes a bias module, a sampling voltage generation module, a reference voltage generation module, a comparator, a Schmitt circuit for generating rising and falling thresholds, and an over-temperature protection circuit. The over-temperature protection circuit includes a trigger MOS transistor M37 connected to an ADC circuit and a cascade driver connected to both the Schmitt circuit and the trigger MOS transistor M37. When the circuit temperature exceeds the rising threshold or falls below the falling threshold, the cascade driver controls the trigger MOS transistor M37 to change its conduction state, thereby implementing over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver controls the trigger MOS transistor M37 to return to its initial conduction state or a predetermined conduction operating state, thereby resuming normal operation of the ADC circuit. The present invention can effectively prevent damage to electronic components in the ADC circuit due to overheating, thereby improving the reliability and service life of the ADC circuit.

Description

Technical Field

[0001] The present invention belongs to the technical field of analog-to-digital converters, and in particular relates to an over-temperature protection circuit with rising and falling thresholds. Background Art

[0002] With the rapid development of modern electronic technology, analog-to-digital converters (ADCs) play a vital role in numerous electronic systems. ADCs accurately convert real-world analog signals into digital signals for subsequent processing, storage, and transmission by digital circuits. They are widely used in fields such as communications, healthcare, industrial control, and aerospace.

[0003] However, as a complex semiconductor device, the performance of ADC is significantly dependent on the ambient temperature. In actual operation, excessively high temperatures may cause internal circuit performance degradation, parameter drift, or even permanent damage. Excessively high temperatures can also affect the accuracy, linearity, and stability of the ADC, causing large errors in the conversion results, thereby affecting the reliability of the entire electronic system.

[0004] Therefore, the present invention provides an over-temperature protection circuit with rising and falling thresholds to solve the above technical problems. Summary of the Invention

[0005] In response to the above problems, the present invention aims to provide an over-temperature protection circuit with rising and falling thresholds, which has an over-temperature protection function and can effectively prevent damage to electronic components in the ADC circuit due to overheating, thereby improving the reliability and service life of the ADC circuit.

[0006] The present invention provides an over-temperature protection circuit with rising and falling thresholds, comprising:

[0007] A bias module, used to generate stable bias current and bias voltage;

[0008] a sampling voltage generating module, connected to the bias module, and configured to convert the bias current generated by the bias module into a sampling voltage signal;

[0009] A reference voltage generating module, which is used to generate a reference voltage signal;

[0010] a comparator, connected to both the sampling voltage generating module and the reference voltage generating module, configured to compare the sampling voltage signal with the reference voltage signal and output a comparison result signal;

[0011] A Schmitt circuit, comprising a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a transistor Q2, and a transistor Q3, wherein the gate of the transistor Q2 is connected to the output terminal of the comparator, and is configured to receive the comparison result signal and perform signal processing on the comparison result signal to generate a rising threshold and a falling threshold for preventing thermal oscillation;

[0012] An over-temperature protection circuit includes a trigger MOS transistor M37 connected to an ADC circuit and a cascade driver connected to the transistor Q3, the resistor R5, and the trigger MOS transistor M37. When the circuit temperature exceeds a rising threshold or falls below a falling threshold, the cascade driver controls the trigger MOS transistor M37 to change its conduction state to implement over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver controls the trigger MOS transistor M37 to return to an initial conduction state or a predetermined conduction operating state to restore the ADC circuit to normal operation.

[0013] Preferably, the bias module adopts a current mirror structure, and the current mirror structure includes a first current mirror structure and a second current mirror structure; the first current mirror structure is composed of transistors M1-M8 connected, and the second current mirror structure is composed of transistors M20-M23 connected.

[0014] Preferably, the reference voltage generation module includes a transistor Q1 and a first RC filter; the sampling voltage generation module includes a resistor R3 and a second RC filter; the comparator is composed of transistors M9-M17 connected together; the transistor Q1 is used to generate the reference voltage signal, and the first RC filter is simultaneously connected to the emitter of the transistor Q1, the collector of the transistor Q1, and the gate of the transistor M10, for filtering the reference voltage signal and transmitting the filtered reference voltage signal to the transistor M10; the resistor R3 is connected to the second current mirror structure, for converting the bias current into the sampling voltage signal, and the second RC filter is simultaneously connected to the resistor R3 and the gate of the transistor M11, for filtering the sampling voltage signal and transmitting the filtered sampling voltage signal to the transistor M11.

[0015] Preferably, the drain of the transistor M11 is connected to the drain of the transistor M15 and then connected to the gate of the transistor Q2, so that a specific electrical connection relationship is established between the Schmitt circuit and the comparator.

[0016] Preferably, the cascade driver is composed of transistors M31-M36 connected together, and the drain of the transistor M31 is connected to the drain of the transistor M32 and then connected to the collector of the transistor Q3 and the resistor R5, so that a specific electrical connection relationship is established between the Schmitt circuit and the cascade driver; the drain of the transistor M35 is connected to the drain of the transistor M36 and then connected to the gate of the trigger MOS tube M37.

[0017] Preferably, the first RC filter is composed of a resistor R1 connected to a transistor M18; the second RC filter is composed of a resistor R2 connected to a transistor M19.

[0018] Compared to related art, the present invention provides an over-temperature protection circuit with rising and falling thresholds, comprising a bias module, a sampling voltage generation module, a reference voltage generation module, a comparator, a Schmitt circuit for generating rising and falling thresholds, and an over-temperature protection circuit. The over-temperature protection circuit comprises a trigger MOS transistor M37 connected to an ADC circuit and a cascade driver connected to both the Schmitt circuit and the trigger MOS transistor M37. When the circuit temperature exceeds the rising threshold or falls below the falling threshold, the cascade driver controls the trigger MOS transistor M37 to change its conduction state to implement over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver controls the trigger MOS transistor M37 to return to its initial conduction state or a predetermined conduction state, allowing the ADC circuit to resume normal operation. The above-described structural arrangement not only enables timely detection and processing of over-temperature conditions, effectively preventing damage to electronic components in the ADC circuit due to overheating, but also prevents fires or other safety accidents caused by overheating, thereby improving the reliability, service life, and safety of the ADC circuit. Furthermore, the protection threshold can be automatically adjusted according to actual operating conditions to adapt to different temperature environments and operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural block diagram of an over-temperature protection circuit with rising and falling thresholds according to the present invention;

[0020] Figure 2 The present invention is a circuit diagram of an over-temperature protection circuit with rising and falling thresholds. DETAILED DESCRIPTION

[0021] The present invention provides an over-temperature protection circuit with rising and falling thresholds, aiming to solve the problems of poor reliability, small adaptability and low safety of existing ADC circuits.

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Please see the attached Figure 1-2 As shown, the present invention provides an over-temperature protection circuit with rising and falling thresholds, which includes:

[0024] Bias module 1, used to generate stable bias current and bias voltage;

[0025] a sampling voltage generating module 2, connected to the bias module 1, and configured to convert the bias current generated by the bias module into a sampling voltage signal;

[0026] A reference voltage generating module 3, which is used to generate a reference voltage signal;

[0027] a comparator 4, connected to both the sampling voltage generating module 2 and the reference voltage generating module 3, for comparing the sampling voltage signal with the reference voltage signal and outputting a comparison result signal;

[0028] a Schmitt circuit 5, which is composed of a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a transistor Q2, and a transistor Q3, wherein the gate of the transistor Q2 is connected to the output terminal of the comparator 4, and is used to receive the comparison result signal and perform signal processing on the comparison result signal to generate a rising threshold and a falling threshold for preventing thermal oscillation;

[0029] The over-temperature protection circuit 6 includes a trigger MOS transistor M37 connected to the ADC circuit and a cascade driver 61 connected to the transistor Q3, the resistor R5, and the trigger MOS transistor M37. When the circuit temperature exceeds the rising threshold or falls below the falling threshold, the cascade driver 61 controls the trigger MOS transistor M37 to change its conduction state to implement over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver 61 controls the trigger MOS transistor M37 to return to an initial conduction state or a predetermined conduction working state to resume normal operation of the ADC circuit.

[0030] In the above structure, when overtemperature occurs, a high-level signal is generated. This high-level signal is transmitted to the trigger MOS transistor M37. The increased voltage causes the trigger MOS transistor M37 to conduct, lowering the resistance of the signal transmission path. Normal operation resumes after the temperature cools. This structure not only allows for timely detection and processing of overtemperature conditions, effectively preventing damage to electronic components in the ADC circuit due to overheating, but also prevents fires or other safety incidents caused by overheating, thereby improving the reliability, service life, and safety of the ADC circuit. Furthermore, the protection threshold can be automatically adjusted based on actual operating conditions to adapt to different temperature environments and operating conditions.

[0031] In this embodiment, the bias module 1 adopts a current mirror structure, and the current mirror structure includes a first current mirror structure 11 and a second current mirror structure 12; the first current mirror structure 11 is composed of transistors M1-M8 connected, and the second current mirror structure 12 is composed of transistors M20-M23 connected.

[0032] Specifically, the reference voltage generation module 3 includes a transistor Q1 and a first RC filter; the sampling voltage generation module 2 includes a resistor R3 and a second RC filter; the comparator 4 is composed of transistors M9-M17 connected together; the transistor Q1 is used to generate the reference voltage signal, and the first RC filter is simultaneously connected to the emitter of the transistor Q1, the collector of the transistor Q1, and the gate of the transistor M10, for filtering the reference voltage signal and transmitting the filtered reference voltage signal to the transistor M10; the resistor R3 is connected to the second current mirror structure 12, for converting the bias current into the sampling voltage signal, and the second RC filter is simultaneously connected to the resistor R3 and the gate of the transistor M11, for filtering the sampling voltage signal and transmitting the filtered sampling voltage signal to the transistor M11.

[0033] In this embodiment, the first RC filter is formed by connecting a resistor R1 and a transistor M18; the second RC filter is formed by connecting a resistor R2 and a transistor M19.

[0034] Furthermore, the drain of the transistor M11 is connected to the drain of the transistor M15 and then connected to the gate of the transistor Q2 , so that a specific electrical connection relationship is established between the Schmitt circuit 5 and the comparator 4 .

[0035] Furthermore, the cascade driver 61 is composed of transistors M31-M36, and the drain of the transistor M31 is connected to the drain of the transistor M32 and then connected to the collector of the transistor Q3 and the resistor R5, so that a specific electrical connection relationship is established between the Schmitt circuit 5 and the cascade driver 61; the drain of the transistor M35 is connected to the drain of the transistor M36 and then connected to the gate of the trigger MOS tube M37.

[0036] It should be noted that, in order to facilitate understanding of the technical solution of the present invention, the principle of the above structure is explained below:

[0037] The present invention provides an over-temperature protection circuit with rising and falling thresholds. Under normal temperature conditions, it is assumed that the current in the circuit follows the formula I = IPTAT = VTln(n) / R, where VT is the thermal voltage, n is a parameter related to transistor characteristics, and R is the specific resistance value. At this time, the voltage between the base B and emitter E of transistor Q1 is VBE0, the temperature coefficient is A, and the initial setting VA>VB, where VA is the reference voltage signal generated by the reference voltage generation module 2, and VB is the sampling voltage signal generated by the sampling voltage generation module 2. In this state, OTP is triggered to a high level, and transistor M11 is turned on, so that the voltage on resistor R1 is zero, and it is obtained. V A =V BE =V BEO -AT; As the temperature continues to rise, VA decreases due to the negative temperature coefficient of the transistor. When the threshold value of the shutdown temperature is reached, VA = VB, the threshold point Toff at this time can be calculated as: When the temperature continues to rise, VB will be greater than VA, and the output of comparator 4 will be low. At this time, transistor M11 will be turned off. At this time, the output OTP of over-temperature protection circuit 6 will be low, making the entire circuit in the off state. When the temperature starts to drop, the output OTP of over-temperature protection circuit 6 will be low at the beginning, transistor M11 will be in the off state, and the entire circuit will also be in the off state. At this time, the voltage of VB is: As the temperature continues to drop, VB will gradually decrease and VA will gradually increase. When VA is equal to VB, the circuit will start working again. The temperature threshold point Ton at this time is: When the temperature drops below Ton, the circuit will resume normal operation. Based on the above analysis, the temperature hysteresis ΔT of the over-temperature protection circuit can be calculated as follows:

[0038] The off temperature Toff can be adjusted by resistor R2, while the temperature hysteresis ΔT can be adjusted by resistor R1.

[0039] Compared to related art, the present invention provides an over-temperature protection circuit with rising and falling thresholds, comprising a bias module, a sampling voltage generation module, a reference voltage generation module, a comparator, a Schmitt circuit for generating rising and falling thresholds, and an over-temperature protection circuit. The over-temperature protection circuit comprises a trigger MOS transistor M37 connected to an ADC circuit and a cascade driver connected to both the Schmitt circuit and the trigger MOS transistor M37. When the circuit temperature exceeds the rising threshold or falls below the falling threshold, the cascade driver controls the trigger MOS transistor M37 to change its conduction state to implement over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver controls the trigger MOS transistor M37 to return to its initial conduction state or a predetermined conduction state, allowing the ADC circuit to resume normal operation. The above-described structural arrangement not only enables timely detection and processing of over-temperature conditions, effectively preventing damage to electronic components in the ADC circuit due to overheating, but also prevents fires or other safety accidents caused by overheating, thereby improving the reliability, service life, and safety of the ADC circuit. Furthermore, the protection threshold can be automatically adjusted according to actual operating conditions to adapt to different temperature environments and operating conditions.

[0040] The embodiments described above are to be understood as illustrative rather than limiting the scope of the present invention, which is to be determined by the claims. It will be apparent to those skilled in the art that non-essential improvements and adjustments to the present invention, without departing from the spirit and scope of the present invention, still fall within the scope of the present invention.

Claims

1. An over-temperature protection circuit with rising and falling thresholds, characterized in that: The over-temperature protection circuit with rising and falling thresholds includes A bias module, used to generate stable bias current and bias voltage; a sampling voltage generating module, connected to the bias module, and configured to convert the bias current generated by the bias module into a sampling voltage signal; A reference voltage generating module, which is used to generate a reference voltage signal; a comparator, connected to both the sampling voltage generating module and the reference voltage generating module, configured to compare the sampling voltage signal with the reference voltage signal and output a comparison result signal; A Schmitt circuit, comprising a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a transistor Q2, and a transistor Q3, wherein the gate of the transistor Q2 is connected to the output terminal of the comparator, and is configured to receive the comparison result signal and perform signal processing on the comparison result signal to generate a rising threshold and a falling threshold for preventing thermal oscillation; An over-temperature protection circuit includes a trigger MOS transistor M37 connected to the ADC circuit and a cascade driver connected to the transistor Q3, the resistor R5, and the trigger MOS transistor M37. When the circuit temperature exceeds the rising threshold or falls below the falling threshold, the cascade driver controls the trigger MOS transistor M37 to change its conduction state, thereby implementing over-temperature protection for the ADC circuit. When the circuit temperature returns to a normal range, the cascade driver controls the trigger MOS tube M37 to return to an initial conduction state or a predetermined conduction working state, so that the ADC circuit resumes normal operation.

2. The over-temperature protection circuit with rising and falling thresholds according to claim 1, characterized in that: The bias module adopts a current mirror structure, and the current mirror structure includes a first current mirror structure and a second current mirror structure; the first current mirror structure is composed of transistors M1-M8 connected, and the second current mirror structure is composed of transistors M20-M23 connected.

3. The over-temperature protection circuit with rising and falling thresholds according to claim 2, characterized in that: The reference voltage generation module includes a transistor Q1 and a first RC filter; the sampling voltage generation module includes a resistor R3 and a second RC filter; the comparator is composed of transistors M9-M17 connected together; the transistor Q1 is used to generate the reference voltage signal, and the first RC filter is connected to the emitter of the transistor Q1, the collector of the transistor Q1, and the gate of the transistor M10 to filter the reference voltage signal and transmit the filtered reference voltage signal to the transistor M10; The resistor R3 is connected to the second current mirror structure for converting the bias current into the sampled voltage signal. The second RC filter is connected to the resistor R3 and the gate of the transistor M11 for filtering the sampled voltage signal and transmitting the filtered sampled voltage signal to the transistor M11.

4. The over-temperature protection circuit with rising and falling thresholds according to claim 3, characterized in that: The drain of the transistor M11 is connected to the drain of the transistor M15 and then connected to the gate of the transistor Q2, so that a specific electrical connection relationship is established between the Schmitt circuit and the comparator.

5. The over-temperature protection circuit with rising and falling thresholds according to claim 4, characterized in that: The cascade driver is composed of transistors M31-M36 connected together, and the drain of the transistor M31 is connected to the drain of the transistor M32 and then connected to the collector of the transistor Q3 and the resistor R5, so that a specific electrical connection relationship is established between the Schmitt circuit and the cascade driver; the drain of the transistor M35 is connected to the drain of the transistor M36 and then connected to the gate of the trigger MOS tube M37.

6. The over-temperature protection circuit with rising and falling thresholds according to claim 5, characterized in that: The first RC filter is formed by connecting a resistor R1 and a transistor M18; the second RC filter is formed by connecting a resistor R2 and a transistor M19.

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