An over / under voltage detection circuit

Abstract

The application provides an over / under voltage detection circuit, which comprises a chip to be detected, the chip to be detected having a voltage detection pin; a current branch arranged in the interior of the chip to be detected and connected with the voltage detection pin, used for providing a non-zero current at the voltage detection pin; and a resistance branch arranged in the exterior of the chip to be detected and connected with the voltage detection pin, used for setting overvoltage protection points and under-voltage protection points under the action of the current branch, and adjusting the proportion of the overvoltage protection points and the under-voltage protection points, so as to realize overvoltage protection and under-voltage protection of the chip to be detected. OVP The application provides the over / under voltage detection circuit, which solves the problem that the application is limited due to the fixed proportion of U1 UVP and U1 UVP .

Description

Technical Field

[0001] The present invention relates to the field of integrated circuits, and in particular to an over-voltage and under-voltage detection circuit. Background Art

[0002] For the power supply system, voltage protection is required when the voltage at a certain point is too high or too low. There is a voltage detection solution such as Figure 1 As shown, it uses two independent pins to detect the voltage of the power chip, one pin is used to detect overvoltage, and the other pin is used to detect undervoltage; the advantage of this method is that the overvoltage protection point and undervoltage protection point of the measured voltage can be adjusted, and the two are independent of each other and do not affect each other; its disadvantage is that the peripheral detection circuit is slightly complicated, and two pins are required for judgment. When the chip itself does not have enough pins, its functions need to be compromised, or the package with more pins needs to be replaced, which will inevitably lead to an increase in chip cost.

[0003] There is another voltage detection scheme such as Figure 2 As shown, it will Figure 1 The two pins in the circuit are combined and the voltage is detected through one pin; the overvoltage protection point of the measured voltage is Undervoltage protection point of the measured voltage Where: R1 is the first resistor, R2 is the second resistor, OVP is the overvoltage reference inside the chip, and UVP is the undervoltage reference inside the chip. In this solution, U1 is adjusted by adjusting the resistance of R1 and R2. OVP and U1 UVP , but no matter how you change the resistance of R1 and R2, U1 OVP and U1 UVP The ratio of U1 is fixed and cannot be adjusted. OVP and U1 UVP There are different requirements. Although the above solution has a simple peripheral detection circuit, due to U1 OVP and U1 UVP The ratio is fixed, and the two can only be adjusted at the same time, and only one of them cannot be adjusted, which limits the application. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an over-voltage and under-voltage detection circuit for solving the problem of the existing detection circuit due to U1 OVP and U1 UVP The problem of limited application is caused by the fixed ratio.

[0005] To achieve the above-mentioned and other related purposes, the present invention provides an overvoltage and undervoltage detection circuit, the overvoltage and undervoltage detection circuit comprising:

[0006] a chip to be detected, the chip to be detected having a voltage detection pin;

[0007] a current branch, arranged inside the chip to be detected and connected to the voltage detection pin, for providing a non-zero current at the voltage detection pin;

[0008] a resistance branch, arranged outside the chip to be detected and connected to the voltage detection pin, for setting overvoltage protection point and undervoltage protection point under the action of the current branch, and adjusting the proportion of the two, so as to realize overvoltage protection and undervoltage protection of the chip to be detected.

[0009] Optionally, the current branch comprises a current source, and the current source is connected to the voltage detection pin.

[0010] Optionally, the current branch comprises a current source, and a current input end of the current source is connected to the voltage detection pin, and a current output end of the current source is grounded.

[0011] Optionally, the current branch comprises a current source, and a current input end of the current source is connected to the voltage detection pin, and a current output end of the current source is grounded.

[0012] Optionally, the resistance branch comprises a first detection resistance and a second detection resistance, one end of the first detection resistance is connected to a measured voltage, the other end of the first detection resistance is connected to one end of the second detection resistance and the voltage detection pin, and the other end of the second detection resistance is grounded.

[0013] Optionally, the chip to be detected comprises an overvoltage comparator, an undervoltage comparator and a logic controller, wherein,

[0014] a first input end of the overvoltage comparator is connected to the voltage detection pin, a second input end of the overvoltage comparator is connected to an overvoltage reference, and an output end of the overvoltage comparator is connected to the logic controller, for comparing the voltage at the voltage detection pin with the overvoltage reference and outputting a comparison result;

[0015] a first input end of the overvoltage comparator is connected to the voltage detection pin, a second input end of the overvoltage comparator is connected to an overvoltage reference, and an output end of the overvoltage comparator is connected to the logic controller, for comparing the voltage at the voltage detection pin with the overvoltage reference and outputting a comparison result;

[0016] the logic controller is used for judging whether the chip to be detected is in an overvoltage state or an undervoltage state according to the comparison results output by the overvoltage comparator and the undervoltage comparator.

[0017] Optionally, the chip to be detected comprises a power supply chip.

[0018] As mentioned above, the over-voltage and under-voltage detection circuit of the present application can increase or decrease a non-zero current at the voltage detection pin inside the chip to be detected by adding a current branch, so as to achieve the purpose of setting the over-voltage protection point and the under-voltage protection point through only one chip pin, and the ratio of the two can be adjusted to avoid the limitation of the circuit application. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A schematic diagram of an existing over-voltage and under-voltage detection circuit is shown.

[0020] Figure 2 A schematic diagram of another existing over-voltage and under-voltage detection circuit is shown.

[0021] Figure 3 A schematic diagram of the over-voltage and under-voltage detection circuit according to the first embodiment of the present application is shown.

[0022] Figure 4 A schematic diagram of the over-voltage and under-voltage detection circuit according to the second embodiment of the present application is shown.

[0023] Figure 5 A schematic diagram of the over-voltage and under-voltage detection circuit according to the third embodiment of the present application is shown.

[0024] Element number explanation

[0025] 100 chip to be tested

[0026] 101 over-voltage comparator

[0027] 102 under-voltage comparator

[0028] 103 logic controller

[0029] 200 current branch

[0030] 300 resistance branch DETAILED DESCRIPTION

[0031] The embodiments of the present application will be described in detail with specific reference felt to the drawings. The skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. The present application can also be implemented or applied in other different embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application.

[0032] Reference will be made to Figures 3 to 5It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concepts of the present application, and the diagrams only show the components related to the present application, rather than the number, shape and size of the components in actual implementation. The shape, number and ratio of the components in actual implementation can be arbitrarily changed, and the layout of the components can be more complex.

[0033] Embodiment One

[0034] As shown in the following Figure 3 , the present embodiment provides an over / under voltage detection circuit, which comprises:

[0035] a chip to be detected 100, wherein the chip to be detected 100 has a voltage detection pin DET;

[0036] a current branch 200, which is arranged inside the chip to be detected 100 and connected to the voltage detection pin DET, for providing a non-zero current at the voltage detection pin DET;

[0037] a resistance branch 300, which is arranged outside the chip to be detected 100 and connected to the voltage detection pin DET, for setting overvoltage protection point and under-voltage protection point under the action of the current branch 200, and adjusting the proportion of the two, so as to realize overvoltage protection and under-voltage protection of the chip to be detected 100.

[0038] As an example, the chip to be detected 100 is any existing circuit chip that needs overvoltage protection and under-voltage protection; alternatively, in the present example, the chip to be detected 100 is a power chip.

[0039] As an example, as shown in the following Figure 3 , the chip to be detected 100 comprises an overvoltage comparator 101, an under-voltage comparator 102 and a logic controller 103, wherein,

[0040] the first input end of the overvoltage comparator 101 is connected to the voltage detection pin DET, the second input end is connected to an overvoltage reference OVP, and the output end is connected to the logic controller 103, for comparing the voltage at the voltage detection pin DET with the overvoltage reference OVP and outputting the comparison result;

[0041] the first input end of the under-voltage comparator 102 is connected to the voltage detection pin DET, the second input end is connected to an under-voltage reference UVP, and the output end is connected to the logic controller 103, for comparing the voltage at the voltage detection pin DET with the under-voltage reference UVP and outputting the comparison result;

[0042] The logic controller 103 is used to determine whether the chip to be detected 100 is in an overvoltage state or an undervoltage state according to the comparison results output by the overvoltage comparator 101 and the undervoltage comparator 102, thereby realizing overvoltage protection and undervoltage protection for the chip to be detected 100.

[0043] In this example, the first input terminal of the overvoltage comparator 101 is the inverting input terminal, and the second input terminal of the overvoltage comparator 101 is the non-inverting input terminal; in actual application, when the chip to be detected 100 is overvoltage, the voltage at the voltage detection pin DET gradually increases to the overvoltage reference OVP. At this time, the output of the overvoltage comparator 101 is reversed, that is, from a high level to a low level. The logic controller 103 determines that the chip to be detected 100 is in an overvoltage state according to the output of the overvoltage comparator 101, thereby controlling the relevant circuits to perform overvoltage protection on the chip to be detected 100. The first input end of the undervoltage comparator 102 is a non-inverting input end, and the second input end of the undervoltage comparator 102 is an inverting input end. In actual application, when the chip to be detected 100 is undervoltage, the voltage at the voltage detection pin DET gradually decreases to the undervoltage reference UVP. At this time, the output of the undervoltage comparator 102 is reversed, that is, from a high level to a low level. The logic controller 103 determines that the chip to be detected 100 is in an undervoltage state according to the output of the undervoltage comparator 102, thereby controlling the relevant circuits to perform undervoltage protection on the chip to be detected 100.

[0044] As an example, Figure 3 As shown, the current branch 200 includes a current source I1 connected to the voltage detection pin DET to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs and is not limited in this example.

[0045] As an example, Figure 3 As shown, the resistance branch 300 includes: a first detection resistor R1 and a second detection resistor R2, one end of the first detection resistor R1 is connected to the measured voltage U1, the other end of the first detection resistor R1 is connected to one end of the second detection resistor R2 and the voltage detection pin DET, and the other end of the second detection resistor R2 is grounded.

[0046] like Figure 3 As shown, the overvoltage and undervoltage detection circuit of this embodiment adds a current component that is not affected by R1 and R2 to the voltage detection pin inside the chip to be detected, and its overvoltage protection point is Undervoltage protection point At this time, the ratio of overvoltage protection point to undervoltage protection point is: As can be seen, due to the presence of I1, the change of R1 and R2 can not only adjust the value of U1 OVP and U1 UVP , but also the ratio of the two.

[0047] Embodiment Two

[0048] As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example. Figure 4 As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example.

[0049] Figure 4 As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example. At this time, the ratio of the overvoltage protection point to the under-voltage protection point is: As can be seen, due to the presence of I1, the change of R1 and R2 can not only adjust the value of U1 OVP and U1 UVP , but also the ratio of the two.

[0050] Embodiment Three

[0051] As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example. Figure 5 As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example.

[0052] Figure 5 As shown in the figure, the over / under voltage detection circuit of the present embodiment is different from that of Embodiment One in that the current branch 200 of the present embodiment comprises a current source I1, the current input end of which is connected to the voltage detection pin DET, and the current output end of which is grounded, so as to add a non-zero current I1 at the voltage detection pin DET. It should be noted that the size of the current source I1 can be set according to actual needs, and the size thereof is not limited in the present example. At this time, the ratio of the overvoltage protection point to the under-voltage protection point is: As can be seen, due to the presence of I1, the change of R1 and R2 can not only adjust the value of U1​​​​OVP and U1 UVP The value of U1 and the value of U2 can be adjusted, and the ratio of the two can also be adjusted.

[0053] In summary, the over-voltage and under-voltage detection circuit of the present application can increase or decrease a non-zero current at the voltage detection pin inside the chip to be detected by adding a current branch, so as to achieve the purpose of setting the over-voltage protection point and the under-voltage protection point through only one chip pin, and the ratio of the two can also be adjusted, avoiding the limitation of circuit application. Therefore, the present application effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0054] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. An over-voltage and under-voltage detection circuit, characterized in that: The over-voltage and under-voltage detection circuit comprises: A chip to be detected, wherein the chip to be detected has a voltage detection pin; a current branch, provided inside the chip to be detected and connected to the voltage detection pin, for providing a non-zero current at the voltage detection pin; a resistor branch, disposed outside the chip to be detected and connected to the voltage detection pin, for setting an overvoltage protection point and an undervoltage protection point under the action of the current branch, and adjusting a ratio between the overvoltage protection point and the undervoltage protection point, thereby achieving overvoltage protection and undervoltage protection for the chip to be detected; Wherein, the chip to be detected includes: an overvoltage comparator, an undervoltage comparator and a logic controller; The first input terminal of the overvoltage comparator is connected to the voltage detection pin, the second input terminal thereof is connected to the overvoltage reference, and the output terminal thereof is connected to the logic controller, and is used to compare the voltage at the voltage detection pin with the overvoltage reference and output the comparison result; The undervoltage comparator has a first input connected to the voltage detection pin, a second input connected to the undervoltage reference, and an output connected to the logic controller, for comparing the voltage at the voltage detection pin with the undervoltage reference and outputting a comparison result; The logic controller is used to determine whether the chip to be detected is in an overvoltage state or an undervoltage state according to the comparison results output by the overvoltage comparator and the undervoltage comparator.

2. The over-voltage and under-voltage detection circuit according to claim 1, wherein: The current branch includes: a current source, and the current source is connected to the voltage detection pin.

3. The over-voltage and under-voltage detection circuit according to claim 1, wherein: The current branch includes: a current source, a current input end of the current source is connected to the voltage detection pin, and a current output end of the current source is grounded.

4. The over-voltage and under-voltage detection circuit according to claim 1, wherein: The current branch includes: a current supply resistor, one end of the current supply resistor is connected to a preset voltage, and the other end of the current supply resistor is connected to the voltage detection pin.

5. The over-voltage and under-voltage detection circuit according to claim 1, wherein: The resistance branch includes: a first detection resistor and a second detection resistor, one end of the first detection resistor is connected to the measured voltage, the other end of the first detection resistor is connected to one end of the second detection resistor and the voltage detection pin, and the other end of the second detection resistor is grounded.

6. The over-voltage and under-voltage detection circuit according to claim 1, wherein: The chip to be detected includes a power chip.

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