Low-voltage protection circuit and electronic device
By combining a comparator and a switching circuit with a voltage setting circuit, the design solves the problems of slow response and false triggering in existing low-voltage protection circuits, achieving fast response and stable power supply, and adapting to the voltage regulation needs of different devices.
Patent Information
- Application Number
- CN202423100692.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-16
AI Technical Summary
Existing low-voltage protection circuits have slow response speed, high complexity, high cost, and are prone to false triggering when fluctuating around the power supply voltage threshold, failing to meet the flexible voltage regulation needs of different devices.
A comparator and switching circuit combined with a voltage setting circuit are used. The comparator compares the power supply voltage with the set voltage to control the switching circuit to turn on and off. The voltage setting circuit adjusts the voltage threshold when the voltage fluctuates to avoid false triggering.
It improves the response speed and reliability of the low voltage protection circuit, avoids false triggering caused by power supply voltage fluctuations, and ensures stable power supply to subsequent circuits.
Smart Images
Figure CN223613042U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the technical field of circuit protection, and in particular, to a low-voltage protection circuit and an electronic device. BACKGROUND
[0002] In the field of integrated circuit technology, the reliability of the power supply affects the performance and safety of the entire circuit. Low-voltage protection circuits are widely used in various electronic and electrical devices to ensure that the device can enter a protection state in time when the power supply voltage is abnormal. Low-voltage protection circuits are usually used to avoid failures or damage of electrical equipment due to low voltage, especially in the fields of power supply equipment, power electronic equipment, communication systems, etc., low-voltage protection is particularly important. SUMMARY
[0003] The present disclosure provides a low-voltage protection circuit and an electronic device to improve the reliability of the power supply of the electronic device. In a first aspect, a low-voltage protection circuit is provided, comprising: a comparator, a first input terminal of the comparator being configured to be coupled to a first power supply terminal; a voltage setting circuit connected between the first power supply terminal and a second input terminal of the comparator, configured to provide a first voltage to the comparator based on the voltage of the first power supply terminal; a switch circuit, an input terminal of the switch circuit being configured to be coupled to the first power supply terminal and an output terminal of the comparator; the comparator is further configured to compare the voltage of the first power supply terminal and the first voltage, when the voltage of the first power supply terminal is greater than or equal to the first voltage, the comparator controls the switch circuit to be turned on; when the voltage of the first power supply terminal is less than the first voltage, the comparator controls the switch circuit to be turned off, and the voltage setting circuit adjusts the first voltage to a second voltage, wherein the first voltage is less than the second voltage.
[0004] Optionally, the voltage setting circuit comprises: a first resistor, a second resistor and a first zener diode; the first resistor and the second resistor are connected in series between the first power supply terminal and the first input terminal of the comparator; the anode of the first zener diode is coupled to a ground terminal, and the cathode is coupled between the first resistor and the second resistor.
[0005] Optionally, further comprising: a third resistor and a fourth resistor; the third resistor is connected between the first power supply terminal and the first input terminal of the comparator, and the fourth resistor is connected between the first input terminal of the comparator and the ground terminal.
[0006] Optionally, the switch circuit comprises a first switch tube, a second switch tube, a fifth resistor, a sixth resistor and a seventh resistor; a first end of the first switch tube is coupled to the first power supply end, and a second end of the first switch tube is coupled through the fifth resistor, a third end of the first switch tube is configured to output a voltage of the first power supply end externally when the first switch tube is turned on; a first end of the second switch tube is coupled to the output end of the comparator through the sixth resistor, and a second end of the second switch tube is coupled through the seventh resistor, a second end of the second switch tube is coupled to the ground end, and a third end of the second switch tube is coupled to the second end of the first switch tube.
[0007] Optionally, the voltage setting circuit further comprises a third switch tube, an eighth resistor, a ninth resistor and a tenth resistor; a first end of the third switch tube is coupled to the output end of the comparator, a second end of the third switch tube is coupled to the second input end of the comparator through the eighth resistor; a third end of the third switch tube is coupled to the second end of the third switch tube through the ninth resistor, coupled to the first end of the third switch tube through the tenth resistor, and coupled to the ground end.
[0008] Optionally, further comprising an eleventh resistor connected between the first power supply end and the output end of the comparator.
[0009] Optionally, the first switch tube is a PMOS tube, and the second switch tube and the third switch tube are NMOS tubes.
[0010] Optionally, further comprising a first capacitor connected between the first power supply end and the ground end, and a second capacitor connected between the output end of the switch circuit and the ground end.
[0011] Optionally, a first power supply end of the comparator is coupled to the first power supply end, and a second power supply end of the comparator is coupled to the ground end; further comprising a third capacitor connected between the first power supply end of the comparator and the ground end.
[0012] In a second aspect, an electronic device is provided, comprising the low-voltage protection circuit provided in the first aspect. BRIEF DESCRIPTION OF DRAWINGS
[0013] The following briefly introduces the drawings used in the description of the embodiments of the present disclosure:
[0014] Figure 1 FIG. 1 shows a circuit structure diagram of a low-voltage protection circuit provided in some embodiments of the present application;
[0015] Figure 2 FIG. 2 shows a circuit structure diagram of another low-voltage protection circuit provided in some embodiments of the present application. DETAILED DESCRIPTION
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, specific implementations of the present disclosure will be described below with reference to the drawings. The drawings in the following description are only some embodiments of the present disclosure, and for those of ordinary skill in the art, other drawings or embodiments can be obtained from these drawings or embodiments without creative labor, and adjustments and improvements made without departing from the concept of the present disclosure are within the protection scope of the present disclosure.
[0017] In order to make the drawing simple, each drawing only shows the part related to the embodiment, and it does not represent the actual structure of the product. In addition, in order to make the drawing simple and easy to understand, only some structures or components are shown schematically, and there may be more or less similar structures or components.
[0018] Low voltage protection circuits are widely used in various electrical devices to ensure that the device can enter a protection state in time when the power supply voltage is abnormal. Low voltage protection circuits are usually used to avoid electrical equipment from malfunctioning or being damaged due to low voltage, especially in battery-powered devices, power electronic devices, communication systems, etc. The response speed of existing low voltage protection circuits is usually slow, which may cause the device to be damaged or work abnormally when the voltage drops below the safe range. Secondly, the traditional protection circuit often has high complexity and cost in design, especially in high-precision and high-stability application scenarios, the design and implementation of the circuit still have certain technical problems. At the same time, some existing low voltage protection circuits lack flexibility in adjusting the voltage threshold, and cannot adapt to the needs of different devices, and cannot solve the problem of false triggering of low voltage protection circuit when the power supply voltage fluctuates near the flip threshold. Therefore, the present application provides a low voltage protection circuit, which can ensure the low voltage protection effect while avoiding the false triggering of low voltage protection caused by the fluctuation of power supply voltage near the low voltage threshold. The following will be described in conjunction with the drawings:
[0019] Figure 1A circuit structure diagram of a low-voltage protection circuit provided in some embodiments of the present application is shown. The low-voltage protection circuit 100 includes a comparator 110, a first input end of the comparator 110 is configured to be coupled to a first power supply end V1; a voltage setting circuit 120 connected between the first power supply end V1 and a second input end of the comparator 110, configured to provide a first voltage to the comparator 110 based on a voltage of the first power supply end V1; a switch circuit 130, an input end of the switch circuit 130 is configured to be coupled to the first power supply end V1 and an output end of the comparator 110; the comparator 110 is further configured to compare the voltage of the first power supply end V1 and the first voltage, when the voltage of the first power supply end V1 is greater than or equal to the first voltage, the comparator 110 controls the switch circuit 130 to be turned on; when the voltage of the first power supply end V1 is less than the first voltage, the comparator 110 controls the switch circuit 130 to be turned off, and the voltage setting circuit 120 adjusts the first voltage to a second voltage, wherein the first voltage is less than the second voltage.
[0020] In the above low-voltage protection circuit, the voltage setting circuit 120 can provide a first voltage, which is a threshold voltage, to the comparator 110 through the voltage division of the power supply voltage from the first power supply terminal V1. When the power supply voltage from the first power supply terminal V1 is input to the first input terminal of the comparator 110, the comparator 110 compares the input voltage with the first voltage. For example, when the input voltage is greater than or equal to the current first voltage, it indicates that the power supply voltage is relatively stable and meets the working requirements of the subsequent circuit of the low-voltage protection circuit. Therefore, the comparator 110 can control the switch circuit 130 to be turned on, so that the power supply voltage from the first power supply terminal V1 can be input to the subsequent circuit through the switch circuit 130, thereby realizing normal power supply. When the input voltage is less than the current first voltage, it indicates that the power supply voltage provided by the first power supply terminal V1 is relatively low, which may have an adverse effect on the subsequent circuit connected to the low-voltage protection circuit. There may be a large current in the load, thereby damaging the key components in the subsequent circuit. At this time, the comparator 110 can output a control signal to the switch circuit 130, so that the switch circuit 130 is turned off, thereby disconnecting the subsequent circuit from the first power supply terminal V1, to realize circuit protection. Meanwhile, there may be a phenomenon in the circuit that the power supply voltage from the first power supply terminal V1 is unstable, causing the power supply voltage to fluctuate around the first voltage. In order to avoid the comparator 110 constantly controlling the on-off of the switch circuit 130, so that the power supply voltage is intermittently supplied to the subsequent circuit, the application can raise the first voltage to a second voltage through the voltage setting circuit 120 when the power supply voltage from the first power supply terminal V1 is lower than the first voltage. Since the first voltage as the threshold voltage is raised, the unstable power supply voltage may not meet the condition for the comparator 110 to control the switch circuit 130 to be turned on, thereby avoiding the low-voltage protection circuit being constantly triggered by mistake when the unstable power supply voltage fluctuates around the flip threshold, thereby improving the reliability of the low-voltage protection circuit and providing stable circuit protection for the subsequent circuit.
[0021] Figure 2 A circuit structure diagram of another low-voltage protection circuit provided in some embodiments of the application is shown. The voltage setting circuit 120 includes a first resistor R1, a second resistor R2, and a first zener Z1. The first resistor R1 and the second resistor R2 are connected in series between the first power supply terminal V1 and the first input terminal of the comparator 110. The anode of the first zener Z1 is coupled to the ground terminal, and the cathode is coupled between the first resistor R1 and the second resistor R2.
[0022] In some embodiments, the circuit further includes a third resistor R3 and a fourth resistor R4. The third resistor R3 is connected between the first power supply terminal V1 and the first input terminal of the comparator 110, and the fourth resistor R4 is connected between the first input terminal of the comparator 110 and the ground terminal.
[0023] In some embodiments, the switch circuit 130 comprises a first switch Q1, a second switch Q2, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7. The first terminal of the first switch Q1 is coupled to the first power supply terminal V1, and the second terminal of the first switch Q1 is coupled to the first terminal of the first switch Q1 through the fifth resistor R5. The third terminal of the first switch Q1 is configured to output the voltage of the first power supply terminal V1 when the first switch Q1 is turned on. The first terminal of the second switch Q2 is coupled to the output terminal of the comparator 110 through the sixth resistor R6, and the second terminal of the second switch Q2 is coupled to the second terminal of the second switch Q2 through the seventh resistor R7. The second terminal of the second switch Q2 is coupled to the ground terminal. The third terminal of the second switch Q2 is coupled to the second terminal of the first switch Q1.
[0024] In the above switch circuit 130, when the comparator 110 controls the second switch Q2 to be turned on, the conduction condition of the second switch Q2 can be met correspondingly, so that the power supply voltage of the first power supply terminal V1 can be input to the subsequent circuit. For example, the first terminal of the second switch Q2 is the gate, the second terminal is the source, and the third terminal is the drain. The comparator 110 can control the conduction or turn-off of the second switch Q2 by providing a voltage signal meeting the conduction or turn-off condition to the gate of the second switch Q2. At the same time, the first terminal of the first switch Q1 is the source, the second terminal is the gate, and the third terminal is the drain. After the second switch Q2 is turned on, the gate-source voltage of the first switch Q1 can meet the conduction condition, so that the first switch Q1 is turned on, and the power supply voltage of the first power supply terminal V1 is provided to the subsequent circuit.
[0025] In some embodiments, the voltage setting circuit 120 further comprises a third switch Q3, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10. The first terminal of the third switch Q3 is coupled to the output terminal of the comparator 110. The second terminal of the third switch Q3 is coupled to the second input terminal of the comparator 110 through the eighth resistor R8. The third terminal of the third switch Q3 is coupled to the second terminal of the third switch Q3 through the ninth resistor R9, coupled to the first terminal of the third switch Q3 through the tenth resistor R10, and coupled to the ground terminal.
[0026] The above voltage setting circuit 120, when the comparator 110 determines that the power supply voltage of the first power supply end V1 meets the power supply requirement (i.e., the power supply voltage is greater than or equal to the first voltage), the third switch tube Q3 is turned on at the same time, thereby short-circuiting the ninth resistor R9, and determining the voltage of the first voltage through the voltage division of the first resistor R1, the second resistor R2 and the eighth resistor R8. When the comparator 110 determines that the power supply voltage does not meet the power supply requirement, the third switch tube Q3 is turned off, and the ninth resistor R9 is connected to the circuit due to the high resistance state of the path, and the second input end of the comparator 110 inputs the voltage division based on the first resistor R1, the second resistor R2, the eighth resistor R8 and the ninth resistor R9, so as to raise the first voltage to the second voltage, prevent the power supply voltage from fluctuating around the first voltage (threshold voltage), and cause the low voltage protection to malfunction, thereby providing the reliability of the circuit protection.
[0027] In some embodiments, further comprising an eleventh resistor R11 connected between the first power supply end V1 and the output end of the comparator 110.
[0028] In some embodiments, the first switch tube Q1 is a PMOS tube, and the second switch tube Q2 and the third switch tube Q3 are NMOS tubes.
[0029] In some embodiments, further comprising a first capacitor C1 connected between the first power supply end V1 and the ground end, and a second capacitor C2 connected between the output end of the switch circuit 130 and the ground end.
[0030] The first capacitor C1 can filter and stabilize the power supply voltage provided by the first power supply end V1, so as to ensure that the power supply voltage is smoother and more stable when entering the circuit. The second capacitor C2 can also stabilize the voltage output by the low voltage protection circuit, so as to improve the stability of the voltage output by the low voltage protection circuit.
[0031] In some embodiments, the first power supply end of the comparator 110 is coupled to the first power supply end V1, and the second power supply end of the comparator 110 is coupled to the ground end; further comprising a third capacitor C3 connected between the first power supply end of the comparator 110 and the ground end.
[0032] In a second aspect, an electronic device is provided, comprising the low voltage protection circuit provided in the first aspect.
[0033] In the present disclosure, unless otherwise explicitly specified and limited, ordinal words such as "first", "second", etc. are only used to distinguish the description of the associated objects, and cannot be understood as indicating or implying the relative importance or order between the associated objects. In addition, the ordinal words also do not represent the number of the associated objects.
[0034] "Multiple" includes two or more, and other quantifiers are similar.
[0035] The terms "or," "and / or," used in the disclosure are used to describe associations between items in an inclusive sense, that is, there existence of the associations between the items is not mutually exclusive. For example, "A and / or B" and "A or B" each can include "A," "B," or "A and B," where A and B can include singular or plural items. As another example, "A, B, and / or C," "A, B, or C," and "A, B, and C" each can include "A," "B," "C," "A and B," "A and C," "B and C," or "A, B, and C," where A, B, and C can include singular or plural items. Additionally, " / " in the disclosure is used to represent an "or" relationship between the associated items. The meanings of "at least one of A or B" and "one or more of A and B" in the disclosure are the same as the meaning of "A or B" above, and the meanings of "one or more of A, B, and C" and "at least one of A, B, or C" are the same as the meaning of "A, B, or C" above. The meaning of "one or more of A, B, and C" is the same as the meaning of "A, B, or C" above.
[0036] In the above embodiments, the description of each embodiment is focused on, and the part not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments. In addition, the above embodiments can be freely combined as needed.
Claims
1. A low voltage protection circuit, characterized by, The application relates to a voltage setting circuit, comprising: a comparator, a first input end of the comparator being configured to be coupled with a first power supply end; a voltage setting circuit, connected between the first power supply end and a second input end of the comparator, configured to provide a first voltage to the comparator based on a voltage of the first power supply end; a switch circuit, an input end of the switch circuit being configured to be coupled with the first power supply end and an output end of the comparator; the comparator is further configured to compare the voltage of the first power supply end with the first voltage, when the voltage of the first power supply end is greater than or equal to the first voltage, the comparator controls the switch circuit to be turned on; when the voltage of the first power supply end is less than the first voltage, the comparator controls the switch circuit to be turned off, and the voltage setting circuit adjusts the first voltage to a second voltage, wherein the first voltage is less than the second voltage.
2. The low voltage protection circuit of claim 1, wherein, the voltage setting circuit comprises a first resistor, a second resistor and a first zener diode; the first resistor and the second resistor are connected in series between the first power supply end and the first input end of the comparator; an anode of the first zener diode is coupled with a ground end, and a cathode of the first zener diode is coupled between the first resistor and the second resistor.
3. The low voltage protection circuit of claim 2, wherein, Further comprising: a third resistor and a fourth resistor; the third resistor is connected between the first power supply end and the first input end of the comparator, and the fourth resistor is connected between the first input end of the comparator and the ground end.
4. The low voltage protection circuit of claim 3, wherein, the switch circuit comprises a first switch tube, a second switch tube, a fifth resistor, a sixth resistor and a seventh resistor; a first end of the first switch tube is coupled with the first power supply end, and a second end of the first switch tube is coupled with the first switch tube through the fifth resistor, and a third end of the first switch tube is configured to output the voltage of the first power supply end when the first switch tube is turned on; a first end of the second switch tube is coupled with the output end of the comparator through the sixth resistor, and a second end of the second switch tube is coupled with the ground end through the seventh resistor, and a third end of the second switch tube is coupled with the second end of the first switch tube.
5. The low voltage protection circuit of claim 4, wherein, the voltage setting circuit further comprises a third switch tube, an eighth resistor, a ninth resistor and a tenth resistor; a first end of the third switch tube is coupled with the output end of the comparator, and a second end of the third switch tube is coupled with the second input end of the comparator through the eighth resistor; a third end of the third switch tube is coupled with the second end of the third switch tube through the ninth resistor, coupled with the first end of the third switch tube through the tenth resistor, and coupled with the ground end.
6. The low voltage protection circuit of claim 5, wherein, Further comprising: an eleventh resistor connected between the first power supply end and the output end of the comparator.
7. The low voltage protection circuit of claim 6, wherein, the first switch tube is a PMOS tube, and the second switch tube and the third switch tube are NMOS tubes.
8. The low voltage protection circuit according to any of claims 1-7, characterized in that, Further comprising: a first capacitor connected between the first power supply end and a ground end; a second capacitor connected between an output end of the switch circuit and the ground end.
9. The low voltage protection circuit according to any of claims 1-7, characterized in that, a first power supply end of the comparator is coupled with the first power supply end, and a second power supply end of the comparator is coupled with the ground end; Also included is a third capacitor connected between the first power supply terminal and the ground terminal of the comparator.
10. An electronic device, comprising: The low voltage protection circuit of any one of claims 1-9.