Limit voltage protection circuit with adjustable limit voltage
By designing an adjustable voltage limiting protection circuit, which combines high-voltage and low-voltage limiting circuits with an adjustable voltage circuit, the problem of voltage inability to be adjusted in the circuit is solved, and dynamic adjustment of voltage within a suitable range is achieved, ensuring circuit safety and stability.
Patent Information
- Application Number
- CN202520126371.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-20
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-01-20
AI Technical Summary
The voltage limitation in the existing circuit cannot be adjusted, which cannot meet the different requirements of different circuits for the highest and lowest voltages, and may cause damage to components under abnormal voltage conditions.
An adjustable voltage limiting protection circuit was designed. By combining high-voltage and low-voltage limiting circuits with an adjustable voltage circuit, dynamic voltage regulation is achieved to ensure that the voltage is within a suitable range. The circuit includes a combination of components such as U6A and U6B comparators, D1-D7 diodes, transistors, and amplifiers to achieve multi-level voltage regulation.
It effectively protects the circuit from damage due to excessively high or low voltage, ensures the safety and stability of the circuit, adapts to the voltage requirements of different circuits, and expands the application range of the circuit.
Smart Images
Figure CN223872043U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit technology, and in particular to a voltage limiting protection circuit with adjustable voltage limit. Background Technology
[0002] In electronic devices, circuit stability and safety are paramount. Due to various reasons such as power fluctuations, load changes, and component aging, circuit voltage may rise or fall abnormally, posing a serious threat to normal circuit operation and component lifespan. Therefore, a protective circuit capable of monitoring and limiting voltage is needed to ensure circuit safety and stability. However, voltage-limiting circuits are generally fixed and cannot meet the varying maximum and minimum voltage requirements of different circuits; thus, a circuit capable of adjusting the maximum and minimum voltage limits is needed. Summary of the Invention
[0003] Purpose of the invention: In order to overcome the shortcomings of the existing technology, this utility model provides an adjustable voltage limiting protection circuit. By adjusting the highest and lowest voltage limits, the circuit can be kept stable under various operating conditions, avoiding damage to other components in the circuit due to excessively high or low voltage output by the voltage output circuit, and ensuring the safety and stability of the circuit.
[0004] Technical Solution: To achieve the above objectives, this utility model provides an adjustable voltage limiting protection circuit, comprising a voltage output circuit, a high voltage limiting circuit, a low voltage limiting circuit, a first adjustable voltage circuit, and a second adjustable voltage circuit. The detection terminals of the high voltage limiting circuit and the low voltage limiting circuit are electrically connected to the output terminal of the voltage output circuit. The input terminal of the high voltage limiting circuit is electrically connected to the output terminal of the first adjustable voltage circuit. The first adjustable voltage circuit adjusts and controls the output voltage, serving as the highest limiting voltage of the high voltage limiting circuit. The input terminal of the low voltage limiting circuit is electrically connected to the output terminal of the second adjustable voltage circuit. The second adjustable voltage circuit adjusts and controls the output voltage, serving as the lowest limiting voltage of the low voltage limiting circuit.
[0005] Furthermore, the high-voltage limiting circuit includes a U6A comparator, a D1 diode, and a D4H transistor; the negative input terminal of the U6A comparator is electrically connected to the output terminal of the voltage output circuit through a resistor R4; the output terminal of the U6A comparator is electrically connected to the negative terminal of the D1 diode, the negative terminal of the D1 diode is electrically connected to the base of the D4H transistor through a resistor R2, and the emitter of the D4H transistor is electrically connected to the output terminal of the voltage output circuit.
[0006] Furthermore, the low-voltage limiting circuit includes a U6B comparator, a D7 diode, and a D5L transistor; the negative input terminal of the U6B comparator is electrically connected to the output terminal of the voltage output circuit through a resistor R5; the output terminal of the U6B comparator is electrically connected to the negative terminal of the D7 diode, the negative terminal of the D7 diode is electrically connected to the base of the D5L transistor through a resistor R3, and the emitter of the D5L transistor is electrically connected to the output terminal of the voltage output circuit.
[0007] Furthermore, the first adjustable voltage circuit includes a first amplifier, an MN1 transistor, and an MN2 transistor; the source of the MN1 transistor is electrically connected to the drain and gate of the MN2 transistor, the source of the MN2 transistor is electrically connected to the input terminal of the first amplifier, and the output terminal of the first amplifier is electrically connected to the positive input terminal of the U6A comparator.
[0008] Furthermore, the first adjustable voltage circuit also includes transistors MN3, MN4, and MN5; the source of transistor MN1 is electrically connected to the drain of transistors MN3, MN4, and MN5; the source of transistor MN2 is electrically connected to the source of transistor MP1 and the drain of transistor MN3; the drain of transistor MP1 is electrically connected to the source of transistor MP2 and the drain of transistor MN4; and the drain of transistor MP2 is electrically connected to the drain of transistor MN5.
[0009] Furthermore, the second adjustable voltage circuit includes a second amplifier, an MN6 transistor, and an MN7 transistor; the source of the MN6 transistor is electrically connected to the drain and gate of the MN7 transistor, the source of the MN7 transistor is electrically connected to the input of the second amplifier, and the output of the second amplifier is electrically connected to the positive input of the U6B comparator.
[0010] Furthermore, the second adjustable voltage circuit also includes transistors MN8, MN9, and MN10; the source of transistor MN6 is electrically connected to the drain of transistors MN8, MN9, and MN10; the source of transistor MN7 is electrically connected to the source of transistor MP3 and the drain of transistor MN8; the drain of transistor MP3 is electrically connected to the source of transistor MP4 and the drain of transistor MN9; and the drain of transistor MP4 is electrically connected to the drain of transistor MN10.
[0011] Beneficial effects: This utility model provides an adjustable voltage limiting protection circuit. By controlling the output voltage of the voltage output circuit within a suitable and optimal range through high-voltage limiting circuits and low-voltage limiting circuits, it protects the subsequent circuits from damage due to excessively high voltage and from affecting the operation of subsequent circuits due to excessively low voltage, thus ensuring the safety and stability of the circuit. By controlling the magnitude of the maximum and minimum limiting voltages through two adjustable voltage circuits, it can adapt to the maximum and minimum voltage requirements of different circuits, expanding the application range of the circuit. Attached Figure Description
[0012] Figure 1 Circuit diagram of a voltage limiting protection circuit with adjustable voltage limit. Detailed Implementation
[0013] The present invention will be further described below with reference to the accompanying drawings.
[0014] like Figure 1 As shown, an adjustable voltage limiting protection circuit includes a voltage output circuit 1, a high voltage limiting circuit 2, a low voltage limiting circuit 3, a first adjustable voltage circuit 4, and a second adjustable voltage circuit 5. The detection terminals of the high voltage limiting circuit 2 and the low voltage limiting circuit 3 are electrically connected to the output terminal of the voltage output circuit 1. The input terminal of the high voltage limiting circuit 2 is electrically connected to the output terminal of the first adjustable voltage circuit 4. The first adjustable voltage circuit 4 adjusts and controls the output voltage, which serves as the highest limiting voltage of the high voltage limiting circuit 2. The input terminal of the low voltage limiting circuit 3 is electrically connected to the output terminal of the second adjustable voltage circuit 5. The second adjustable voltage circuit 5 adjusts and controls the output voltage, which serves as the lowest limiting voltage of the low voltage limiting circuit 3.
[0015] like Figure 1 As shown, the high voltage limiting circuit 2 includes a U6A comparator 21, a D1 diode 22, and a D4H transistor 23; the negative input terminal of the U6A comparator 21 is electrically connected to the output terminal of the voltage output circuit 1 through a resistor R4; the output terminal of the U6A comparator 21 is electrically connected to the negative terminal of the D1 diode 22, the negative terminal of the D1 diode 22 is electrically connected to the base of the D4H transistor 23 through a resistor R2, and the emitter of the D4H transistor 23 is electrically connected to the output terminal of the voltage output circuit 1.
[0016] The negative input terminal of the U6A comparator 21 is electrically connected to the output terminal of the U6A comparator 21 through capacitor C2, and the collector of transistor D4H 23 is grounded; the two power supply terminals of the U6A comparator 21 are respectively input to +10V and -10V, the +10V is used as the high level of the output of the U6A comparator 21, and the -10V is used as the low level of the output of the U6A comparator 21.
[0017] like Figure 1 As shown, the low voltage limiting circuit 3 includes a U6B comparator 31, a D7 diode 32, and a D5L transistor 33; the negative input terminal of the U6B comparator 31 is electrically connected to the output terminal of the voltage output circuit 1 through a resistor R5; the output terminal of the U6B comparator 31 is electrically connected to the negative terminal of the D7 diode 32, the negative terminal of the D7 diode 32 is electrically connected to the base of the D5L transistor 33 through a resistor R3, and the emitter of the D5L transistor 33 is electrically connected to the output terminal of the voltage output circuit 1.
[0018] like Figure 1 As shown, the negative input terminal of the U6B comparator 31 is electrically connected to the output terminal of the U6B comparator 31 through capacitor C3, and the collector of the D5L transistor 33 is grounded; the two power supply terminals of the U6B comparator 31 are distributed with inputs of +10V and -10V, with +10V serving as the high level output of the U6B comparator 31 and -10V serving as the low level output of the U6B comparator 31.
[0019] The first adjustable voltage circuit 4 includes a first amplifier 41, an MN1 transistor, and an MN2 transistor; the source of the MN1 transistor is electrically connected to the drain and gate of the MN2 transistor, the source of the MN2 transistor is electrically connected to the input terminal of the first amplifier 41, and the output terminal of the first amplifier 41 is electrically connected to the positive input terminal of the U6A comparator 21.
[0020] like Figure 1 As shown, the first adjustable voltage circuit 4 further includes transistors MN3, MN4, and MN5. The source of transistor MN1 is electrically connected to the drains of transistors MN3, MN4, and MN5; the source of transistor MN2 is electrically connected to the source of transistor MP1 and the drain of transistor MN3; the drain of transistor MP1 is electrically connected to the source of transistor MP2 and the drain of transistor MN4; and the drain of transistor MP2 is electrically connected to the drain of transistor MN5. The gates of transistors MN1, MN3, MN4, and MN5 are all grounded, and transistors MN3, MN4, and MN5 have the same aspect ratio and characteristics. The gates of transistors MP1 and MP2 are respectively connected to a control circuit, which outputs a low or high level to control the conduction of transistors MP1 and MP2.
[0021] During operation, if both the gates of transistors MP1 and MP2 are high-level inputs and neither is conducting, then the source and drain of transistor MN3 carry the current, and the source output of transistor MN2 is a voltage similar to the reference voltage Vref. If the gate of transistor MP1 is low-level input and conducts, while the gates of transistors MP2 are both high-level inputs and not conducting, then the source and drain of transistors MN3 and MN4 share the current. The overall width-to-length ratio of the transistors in the circuit becomes twice the original, causing the reference voltage output from the source of transistor MN2 to become Vre. Half of f, the reference voltage is 1 / 2 voltage Vref; the gates of transistors MP1 and MP2 are both input to a low level and are both turned on. At this time, the sources and drains of transistors MN3, MN4, and MN5 share the current, and the overall width-to-length ratio of the transistors in the circuit becomes three times the original, so the reference voltage output from the source of transistor MN2 becomes 1 / 3 of Vref, and the reference voltage is 1 / 3 voltage Vref; at least three voltage levels can be adjusted through the first adjustable voltage circuit 4, so at least three different voltages can be output. The reference voltage output from the source of transistor MN2 is too small, so it is amplified by a first amplifier 41 with a fixed amplification factor, amplifying the three different voltages to a higher limit voltage LMVH that is more suitable for the high voltage limiting circuit 2.
[0022] like Figure 1 As shown, the second adjustable voltage circuit 5 includes a second amplifier 51, an MN6 transistor, and an MN7 transistor; the source of the MN6 transistor is electrically connected to the drain and gate of the MN7 transistor, the source of the MN7 transistor is electrically connected to the input terminal of the second amplifier 51, and the output terminal of the second amplifier 51 is electrically connected to the positive input terminal of the U6B comparator 31.
[0023] like Figure 1As shown, the second adjustable voltage circuit 5 further includes transistors MN8, MN9, and MN10. The source of transistor MN6 is electrically connected to the drains of transistors MN8, MN9, and MN10; the source of transistor MN7 is electrically connected to the source of transistor MP3 and the drain of transistor MN8; the drain of transistor MP3 is electrically connected to the source of transistor MP4 and the drain of transistor MN9; and the drain of transistor MP4 is electrically connected to the drain of transistor MN10. The gate of transistor MN6, and the sources of transistors MN8, MN9, and MN10 are all grounded, and transistors MN8, MN9, and MN10 have the same aspect ratio and characteristics. The gates of transistors MP3 and MP4 are connected to a control circuit, which outputs a low or high level to control the conduction of transistors MP3 and MP4, respectively. Controlling the output voltage through transistors reduces circuit power consumption and saves circuit resources.
[0024] During operation, if both the gates of the MP3 and MP4 transistors are input with a high level, they are not conducting. In this case, the source and drain of the MN8 transistor carry the current, and the source output of the MN7 transistor is similar to the reference voltage Vref. When the gate of the MP3 transistor is input with a low level, it conducts, and the gates of the MP4 transistors are both input with a high level, they are not conducting. In this case, the source and drain of the MN8 transistor and the source and drain of the MN9 transistor share the current. The overall width-to-length ratio of the transistors in the circuit becomes twice the original, causing the reference voltage output from the source of the MN7 transistor to become Vre. Half of f, the reference voltage is 1 / 2 voltage Vref; the gates of MP3 and MP4 transistors are both input to a low level and are both turned on. At this time, the sources and drains of transistors MN8, MN9, and MN10 share the current, and the overall width-to-length ratio of the transistors in the circuit becomes three times the original, so that the reference voltage output from the source of transistor MN2 becomes 1 / 3 of Vref, and the reference voltage is 1 / 3 voltage Vref; at least three voltage levels can be adjusted through the first adjustable voltage circuit 4, so at least three different voltages can be output. The reference voltage output from the source of transistor MN7 is too small, so it is amplified by a second amplifier 51 with a fixed amplification factor, amplifying the three different voltages to a minimum limiting voltage LMVL that is more suitable for the low voltage limiting circuit 3.
[0025] Example
[0026] During normal operation, the first adjustable voltage circuit 4 selects a suitable voltage value from the three voltage levels as the highest limiting voltage LMVH of the high voltage limiting circuit 2; the second adjustable voltage circuit 5 selects a suitable voltage value from the three voltage levels as the lowest limiting voltage LMVL of the low voltage limiting circuit 3. At this time, the OUT voltage output by the voltage output circuit 1 is compared with the TMV voltage obtained by the negative input terminal of the U6A comparator 21 in the high voltage limiting circuit 2 through the resistor R4. When the TMV voltage is higher than the highest limiting voltage LMVH, the U6A comparator 21 outputs a low level -10V. Since the low level is a negative voltage, it can be output through diode D1 to transistor D4H, so that the OUT voltage output by the voltage output circuit 1 is grounded through the emitter and collector of transistor D4H, preventing the OUT voltage output by the voltage output circuit 1 from being input to the subsequent circuit.
[0027] Similarly, in the low-voltage limiting circuit 3, the negative input terminal of comparator 31 (U6B) collects the OUT voltage output from voltage output circuit 1 via resistor R5 as the TMV voltage and compares it with the minimum limiting voltage LMVL at the positive input terminal of comparator 31 (U6B). When the TMV voltage is lower than the minimum limiting voltage LMVL, comparator 31 (U6B) outputs a high level of +10V. Since a high level is a positive voltage, it can be output through diode D7 to transistor D5L 32, causing the OUT voltage output from voltage output circuit 1 to be grounded through the emitter and collector of transistor D4H. This prevents the OUT voltage output from voltage output circuit 1 from being input to subsequent circuits. This limits the OUT voltage output from voltage output circuit 1 to protect subsequent circuits.
[0028] Simultaneously, when the maximum voltage required by the subsequent circuit becomes smaller and the minimum voltage becomes larger, the control circuit can control the conduction or cutoff of transistors MP1 and MP2, as well as transistors MP3 and MP4, to change the reference voltage outputs of the first adjustable voltage circuit 4 and the second adjustable voltage circuit 5. These changed maximum limit voltages LMVH and LMVL are then amplified to obtain the modified maximum limit voltages LMVH and LMVL, making them suitable for the subsequent circuit. Similarly, when the maximum voltage required by the subsequent circuit increases and the minimum voltage decreases, or when both the maximum and minimum voltages increase or decrease simultaneously, the control circuit can control the conduction or cutoff of transistors MP1 and MP2, as well as transistors MP3 and MP4, to ensure that the first adjustable voltage circuit 4 and the second adjustable voltage circuit 5 output appropriate maximum and minimum limit voltages.
[0029] The above description is merely a preferred embodiment of the present utility model. Those skilled in the art can make several modifications and optimizations based on the above disclosure without departing from the basic principles described above. These modifications and optimizations should be considered as the scope of protection of the present utility model as understood.
Claims
1. A voltage limiting protection circuit with adjustable voltage, characterized in that: It includes a voltage output circuit (1), a high voltage limiting circuit (2), a low voltage limiting circuit (3), a first adjustable voltage circuit (4), and a second adjustable voltage circuit (5); the detection terminals of the high voltage limiting circuit (2) and the low voltage limiting circuit (3) are electrically connected to the output terminal of the voltage output circuit (1), the input terminal of the high voltage limiting circuit (2) is electrically connected to the output terminal of the first adjustable voltage circuit (4), the first adjustable voltage circuit (4) adjusts and controls the output voltage and serves as the highest limiting voltage of the high voltage limiting circuit (2); the input terminal of the low voltage limiting circuit (3) is electrically connected to the output terminal of the second adjustable voltage circuit (5); the second adjustable voltage circuit (5) adjusts and controls the output voltage and serves as the lowest limiting voltage of the low voltage limiting circuit (3).
2. The voltage limiting adjustable protection circuit according to claim 1, characterized in that: The high voltage limiting circuit (2) includes a U6A comparator (21), a D1 diode (22), and a D4H transistor (23); the negative input terminal of the U6A comparator (21) is electrically connected to the output terminal of the voltage output circuit (1) through a resistor R4; the output terminal of the U6A comparator (21) is electrically connected to the negative terminal of the D1 diode (22), the negative terminal of the D1 diode (22) is electrically connected to the base of the D4H transistor (23) through a resistor R2, and the emitter of the D4H transistor (23) is electrically connected to the output terminal of the voltage output circuit (1).
3. The voltage limiting adjustable protection circuit according to claim 1, characterized in that: The low voltage limiting circuit (3) includes a U6B comparator (31), a D7 diode (32), and a D5L transistor (33); the negative input terminal of the U6B comparator (31) is electrically connected to the output terminal of the voltage output circuit (1) through a resistor R5; the output terminal of the U6B comparator (31) is electrically connected to the negative terminal of the D7 diode (32), the negative terminal of the D7 diode (32) is electrically connected to the base of the D5L transistor (33) through a resistor R3, and the emitter of the D5L transistor (33) is electrically connected to the output terminal of the voltage output circuit (1).
4. The voltage limiting adjustable protection circuit according to claim 2, characterized in that: The first adjustable voltage circuit (4) includes a first amplifier (41), an MN1 transistor and an MN2 transistor; the source of the MN1 transistor is electrically connected to the drain of the MN2 transistor and the gate of the MN2 transistor, the source of the MN2 transistor is electrically connected to the input terminal of the first amplifier (41), and the output terminal of the first amplifier (41) is electrically connected to the positive input terminal of the U6A comparator (21).
5. The voltage limiting adjustable protection circuit according to claim 4, characterized in that: The first adjustable voltage circuit (4) further includes transistors MN3, MN4, and MN5; the source of transistor MN1 is electrically connected to the drain of transistors MN3, MN4, and MN5; the source of transistor MN2 is electrically connected to the source of transistor MP1 and the drain of transistor MN3; the drain of transistor MP1 is electrically connected to the source of transistor MP2 and the drain of transistor MN4; and the drain of transistor MP2 is electrically connected to the drain of transistor MN5.
6. The voltage limiting adjustable protection circuit according to claim 3, characterized in that: The second adjustable voltage circuit (5) includes a second amplifier (51), an MN6 transistor and an MN7 transistor; the source of the MN6 transistor is electrically connected to the drain of the MN7 transistor and the gate of the MN7 transistor, the source of the MN7 transistor is electrically connected to the input terminal of the second amplifier (51), and the output terminal of the second amplifier (51) is electrically connected to the positive input terminal of the U6B comparator (31).
7. The voltage limiting adjustable protection circuit according to claim 6, characterized in that: The second adjustable voltage circuit (5) further includes transistors MN8, MN9, and MN10; the source of transistor MN6 is electrically connected to the drain of transistors MN8, MN9, and MN10; the source of transistor MN7 is electrically connected to the source of transistor MP3 and the drain of transistor MN8; the drain of transistor MP3 is electrically connected to the source of transistor MP4 and the drain of transistor MN9; and the drain of transistor MP4 is electrically connected to the drain of transistor MN10.