Current detection circuit and electronic equipment

Abstract

The utility model relates to the technical field of current detection, in particular to a current detection circuit and electronic equipment. The current detection circuit comprises a shunt sampling resistor and a current detection unit, wherein the shunt sampling resistor is provided with a first sampling point, a second sampling point and a third sampling point, and a first resistance value between the first sampling point and the third sampling point is equal to the sum of a second resistance value between the first sampling point and the second sampling point and a third resistance value between the second sampling point and the third sampling point; the current detection unit is connected with the first sampling point, the second sampling point and the third sampling point. According to the utility model, the measuring range of current detection can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of current detection, in particular to a current detection circuit and an electronic device. Background Art

[0002] In the related art, in a shunt current detection circuit, the current passing through a shunt sampling resistor is detected by detecting the voltage across the shunt sampling resistor. Since the resistance value of the shunt sampling resistor is fixed, the corresponding current sampling range will also be fixed and unchanged, and the range of current detection is small. Summary of the Utility Model

[0003] The utility model provides a current detection circuit and an electronic device, and the main purpose is to improve the range of current detection.

[0004] According to one aspect of the utility model, a current detection circuit is provided, including: a shunt sampling resistor and a current detection unit; wherein,

[0005] A first sampling point, a second sampling point and a third sampling point are arranged on the shunt sampling resistor, and the first resistance value between the first sampling point and the third sampling point is equal to the sum of the second resistance value between the first sampling point and the second sampling point and the third resistance value between the second sampling point and the third sampling point;

[0006] The current detection unit is respectively connected to the first sampling point, the second sampling point and the third sampling point.

[0007] Optionally, in an embodiment of the utility model, the shunt sampling resistor includes a substrate; wherein,

[0008] The first sampling point, the second sampling point and the third sampling point are all arranged on the substrate;

[0009] A hollowed-out area is arranged on the substrate, and the hollowed-out area is used to adjust the proportion of the second resistance value and the third resistance value in the first resistance value.

[0010] Optionally, in an embodiment of the utility model, the substrate includes a first material area and a second material area; wherein,

[0011] The first sampling point, the second sampling point and the third sampling point are all connected to the second material area;

[0012] The hollowed-out area is arranged in the first material area;

[0013] The conductivity of the second material area is lower than that of the first material area.

[0014] Optionally, in an embodiment of the present utility model, the second material region is disposed in the middle of the first material region, and the second material region divides the first material region into a first sub-region and a second sub-region. The first sampling point is disposed in the first sub-region and connected to the first end of the second material region, the second sampling point is disposed in the second sub-region and connected to the first end of the second material region, and the third sampling point is disposed in the second sub-region and connected to the second end of the second material region.

[0015] Optionally, in an embodiment of the present utility model, the material corresponding to the first material region is copper, and the material corresponding to the second material region is an alloy.

[0016] Optionally, in an embodiment of the present utility model, the proportions of the second resistance value and the third resistance value in the first resistance value are determined by at least one of the following factors:

[0017] The area of the hollowed-out region;

[0018] The position of the hollowed-out region;

[0019] The shape of the hollowed-out region.

[0020] Optionally, in an embodiment of the present utility model, the current detection unit includes a first current detection sub-unit, a second current detection sub-unit, and a third current detection sub-unit; wherein,

[0021] The first input end of the first current detection sub-unit is connected to the first sampling point, and the second input end of the first current detection sub-unit is connected to the third sampling point;

[0022] The first input end of the second current detection sub-unit is connected to the first sampling point, and the second input end of the second current detection sub-unit is connected to the second sampling point;

[0023] The first input end of the third current detection sub-unit is connected to the second sampling point, and the second input end of the third current detection sub-unit is connected to the third sampling point.

[0024] Optionally, in an embodiment of the present utility model, the current detection unit further includes a first redundant current detection sub-unit, a second redundant current detection sub-unit, and a third redundant current detection sub-unit; wherein,

[0025] The first redundant current detection sub-unit, the second redundant current detection sub-unit, and the third redundant current detection sub-unit are used to detect the working state of the current detection circuit.

[0026] Optionally, in an embodiment of the present utility model, the first redundant current detection sub-unit includes a first voltage comparator, the second redundant current detection sub-unit includes a second voltage comparator, and the third redundant current detection sub-unit includes a third voltage comparator; wherein,

[0027] When the current detection circuit is in normal operation, the first voltage output by the first voltage comparator is equal to the sum of the second voltage output by the second voltage comparator and the third voltage output by the third voltage comparator.

[0028] According to another aspect of the present invention, there is provided an electronic device, comprising: a power supply module and the current detection circuit as described in any one of the foregoing aspects.

[0029] In summary, for the current detection circuit and the electronic device provided by the embodiments of the present invention, by providing a first sampling point, a second sampling point, and a third sampling point on the shunt sampling resistor, the current detection unit can perform current sampling according to the first sampling point and the third sampling point, or can perform current sampling according to the first sampling point and the second sampling point, or can also perform current sampling according to the second sampling point and the third sampling point; since the first resistance value between the first sampling point and the third sampling point is equal to the sum of the second resistance value between the first sampling point and the second sampling point and the third resistance value between the second sampling point and the third sampling point, therefore, the current sampling ranges between the first sampling point and the second sampling point and between the second sampling point and the third sampling point are both greater than the current sampling range between the first sampling point and the third sampling point. Compared with the current sampling range between the first sampling point and the third sampling point, the current detection range of the current detection circuit is improved.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0032] Figure 1 FIG. is a schematic structural diagram of a Shunt current detection circuit in the related art provided by an embodiment of the present invention;

[0033] Figure 2 FIG. is a schematic structural diagram of a current detection circuit provided by an embodiment of the present invention.

[0034] Description of reference numerals: shunt sampling resistor 100, alloy material region 101, first sub-region 111, second sub-region 112, second material region 120, hollow region 130, first sampling point 1, second sampling point 2, third sampling point 3, current detection unit 200, first current detection sub-unit 211, second current detection sub-unit 212, third current detection sub-unit 213, first redundant current detection sub-unit 221, second redundant current detection sub-unit 222, third redundant current detection sub-unit 223. Detailed implementation manners

[0035] Here, some embodiments of the present invention will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. Various changes, modifications, and equivalents of the structures described herein will become apparent after understanding the present invention. For example, the connection relationships of the structures described herein are merely examples and are not limited to the connection relationships set forth herein, but can be changed as will be apparent after understanding the present invention, except for the connections that must be made in a specific connection relationship. Additionally, for the sake of clarity and conciseness, the description of features known in the art may be omitted.

[0036] The implementation manners described in some embodiments of the present invention below do not represent all implementation manners consistent with the present invention. On the contrary, they are merely examples of structures consistent with some aspects of the present invention as detailed in the appended claims.

[0037] Figure 1 It is a schematic structural diagram of a Shunt current detection circuit in a related art provided for an embodiment of the present invention. As Figure 1 shown, the shunt sampling resistor 100 includes an alloy material region 101, and the current passing through the shunt sampling resistor 100 is detected by detecting the voltage across the shunt sampling resistor 100.

[0038] As Figure 1 shown, the purpose of setting the three pairs of differential voltage sampling points 1a, 1b, 2a, 2b, 3a, and 3b is to perform redundant current detection and overcurrent detection. Among them, during redundant current detection, the current difference between ADC 1ab and ADC 2ab is compared. If the current difference between ADC 1ab and ADC 2ab is within a certain range, it is considered that the current detection function is normal; when an overcurrent occurs, through OC 1ab , OC 2ab , OC 3abThe current values obtained by these three OCs are compared. If the current values of more than two OCs exceed the overcurrent detection threshold, it is considered that overcurrent has occurred.

[0039] It should be noted that since the resistance value of the shunt sampling resistor 100 is fixed, its corresponding current sampling range will also be fixed and unchanged, and the measurement range of current detection is small. For example, when the resistance value of the shunt sampling resistor 100 is 25 uΩ, the maximum current measurement range of this Shunt current detection circuit is 5200 A. When an open circuit occurs, currents exceeding 5200 A cannot be read. However, the short-circuit current is generally greater than 10000 A. That is to say, this Shunt current detection circuit can only collect part of the short-circuit current, and the current sampling range is low.

[0040] Secondly, this Shunt current detection circuit needs to use three pairs of differential voltage sampling points to achieve redundant current sampling, and uses more ADCs and connecting wire harnesses, resulting in a higher cost.

[0041] The present utility model will be described in detail below with reference to specific embodiments.

[0042] Figure 2 The following is a schematic structural diagram of a current detection circuit provided by an embodiment of the present utility model. As Figure 2 shown,

[0043] As Figure 2 shown, this current detection circuit includes: a shunt sampling resistor 100 and a current detection unit 200; wherein,

[0044] A first sampling point 1, a second sampling point 2, and a third sampling point 3 are provided on the shunt sampling resistor 100. The first resistance value R13 between the first sampling point 1 and the third sampling point 3 is equal to the sum of the second resistance value R12 between the first sampling point 1 and the second sampling point 3 and the third resistance value R13 between the second sampling point 2 and the third sampling point 3;

[0045] The current detection unit 200 is respectively connected to the first sampling point 1, the second sampling point 2, and the third sampling point 3.

[0046] According to some embodiments, the current detection unit 200 can perform current sampling based on the first sampling point 1 and the third sampling point 3, can also perform current sampling based on the first sampling point 1 and the second sampling point 2, and can also perform current sampling based on the second sampling point 2 and the third sampling point 3. Since R13 = R12 + R23, the current sampling ranges between the first sampling point 1 and the second sampling point 2 and between the second sampling point 2 and the third sampling point 3 are both greater than the current sampling range between the first sampling point 1 and the third sampling point 3. Compared with the current sampling range between the first sampling point 1 and the third sampling point 3, the current detection range of the current detection circuit is improved.

[0047] In some embodiments, when the sampled current does not exceed the current sampling range between the first sampling point 1 and the third sampling point 3, the current detection unit 200 may perform current sampling according to the resistance between the first sampling point 1 and the third sampling point 3, and at this time, the current sampling accuracy is relatively high. When the sampled current exceeds the current sampling range between the first sampling point 1 and the third sampling point 3, the current detection unit 200 may perform current sampling according to the resistance between the first sampling point 1 and the second sampling point 2 and / or the resistance between the second sampling point 2 and the third sampling point 3.

[0048] For example, the circuit to be detected is connected to the current detection circuit. When the circuit to be detected is in a normal operating state, its operating current can be sampled through the resistance between the first sampling point 1 and the second sampling point 3 to ensure the current sampling accuracy; when the circuit to be detected is in a short - circuit or over - current state, current detection can be performed according to a larger current sampling range corresponding to the resistance between the first sampling point 1 and the second sampling point 2 and / or the resistance between the second sampling point 2 and the third sampling point 3.

[0049] In addition, the current detection unit 200 can be connected to the first sampling point 1, the second sampling point 2, and the third sampling point 3 respectively only through three connection lines, and compared with Figure 1 the six connection lines required by the Shunt current detection circuit shown, the cost is lower.

[0050] Optionally, as Figure 2 shown, the shunt sampling resistor includes a substrate; wherein,

[0051] the first sampling point 1, the second sampling point 2, and the third sampling point 3 are all arranged on the substrate;

[0052] a hollowed - out area 130 is arranged on the substrate, and the hollowed - out area 130 is used to adjust the proportion of the second resistance value R12 and the third resistance value R23 in the first resistance value R13.

[0053] According to some embodiments, the positions of the first sampling point 1, the second sampling point 2, and the third sampling point 3 on the substrate are not limited, as long as R13 = R12 + R23 is ensured.

[0054] In some embodiments, the specific values of R12, R23, and R13 can be obtained through calibration.

[0055] According to some embodiments, the proportion of the second resistance value R12 and the third resistance value R23 in the first resistance value R13 is determined by at least one of the following factors:

[0056] the area of the hollowed - out area 130;

[0057] The position of the hollowed-out area 130;

[0058] The shape of the hollowed-out area 130.

[0059] In some embodiments, the shape of the hollowed-out area 130 includes, but is not limited to, a rectangle, a U shape, etc.

[0060] It should be noted that by adjusting the proportion of the second resistance value R12 and the third resistance value R23 in the first resistance value R13 through the hollowed-out area 130, therefore, the current sampling range between the first sampling point 1 and the second sampling point 2 and the current sampling range between the second sampling point 2 and the third sampling point 3 can be adjusted. Furthermore, the current detection over the full current range can be achieved, and the current measurement range can reach more than 40000 A, which can improve the flexibility of the current detection circuit during use.

[0061] Optionally, as Figure 2 shown, the substrate includes a first material area and a second material area 120; wherein,

[0062] The first sampling point 1, the second sampling point 2, and the third sampling point 3 are all connected to the second material area 120;

[0063] The hollowed-out area 130 is arranged in the first material area;

[0064] The conductivity of the second material area 120 is lower than that of the first material area.

[0065] It should be noted that since the first sampling point 1, the second sampling point 2, and the third sampling point 3 are all connected to the second material area 120, and the conductivity of the second material area 120 is lower than that of the first material area, therefore, the resistance between the first sampling point 1 and the second sampling point 2, the resistance between the second sampling point 2 and the third sampling point 3, and the resistance between the first sampling point 1 and the third sampling point 3 can all be regarded as the resistance in the second material area 120; in this case, by arranging the hollowed-out area 130 in the first material area, the current path in the second material area 120 can be adjusted, and further the purpose of adjusting the proportion of the second resistance value R12 and the third resistance value R23 in the first resistance value R13 can be achieved.

[0066] Optionally, as Figure 2As shown, the second material region 120 is disposed in the middle of the first material region, and the second material region 120 divides the first material region into a first sub-region 111 and a second sub-region 112. The first sampling point 1 is disposed in the first sub-region 111 and connected to the first end of the second material region 120. The second sampling point 2 is disposed in the second sub-region 112 and connected to the first end of the second material region 120. The third sampling point 3 is disposed in the second sub-region 112 and connected to the second end of the second material region 120. In this case, R13 can be approximately equal to the total resistance value of the second material region 120, and the current sampling accuracy is relatively high when detecting current through the first sampling point 1 and the third sampling point 3. Secondly, a hollowed-out region 130 can be disposed near at least one of the first sampling point 1, the second sampling point 2, and the third sampling point 3. In this case, the effect of resistance adjustment is relatively obvious, and among them, the adjustment effect of the hollowed-out region 130 disposed near the second sampling point 2 is the highest.

[0067] According to some embodiments, the total resistance value of the second material region 120 can be, for example, 25 micro-ohms.

[0068] In some embodiments, the material corresponding to the first material region can be, for example, copper, and the material corresponding to the second material region 120 can be, for example, an alloy.

[0069] Optionally, as Figure 2 shown, the current detection unit includes a first current detection sub-unit 211, a second current detection sub-unit 212, and a third current detection sub-unit 213; wherein,

[0070] The first input end of the first current detection sub-unit 211 is connected to the first sampling point 1, and the second input end of the first current detection sub-unit 211 is connected to the third sampling point 3;

[0071] The first input end of the second current detection sub-unit 212 is connected to the first sampling point 1, and the second input end of the second current detection sub-unit 212 is connected to the second sampling point 2;

[0072] The first input end of the third current detection sub-unit 213 is connected to the second sampling point 2, and the second input end of the third current detection sub-unit 213 is connected to the third sampling point 3.

[0073] According to some embodiments, as Figure 2 shown, the first current detection sub-unit 211, the second current detection sub-unit 212, and the third current detection sub-unit 213 can all include a voltage comparator and an analog-to-digital conversion unit.

[0074] Among them, the voltage comparator can output the voltage difference between two sampling points. For example, the voltage difference U12 between the first sampling point 1 and the second sampling point 2, the voltage difference U13 between the first sampling point 1 and the third sampling point 3, and the voltage difference U23 between the second sampling point 2 and the third sampling point 3. Therefore, the corresponding current value can be obtained according to the voltage difference output by the voltage comparator and the corresponding resistance value.

[0075] Among them, the analog-to-digital conversion unit can be used to convert the analog voltage signal output by the voltage comparator into a digital voltage signal, so as to calculate the corresponding current value according to the digital voltage signal and the corresponding resistance value.

[0076] Optionally, as Figure 2 shown, the current detection unit 200 further includes a first redundant current detection sub-unit 221, a second redundant current detection sub-unit 222, and a third redundant current detection sub-unit 223; among them,

[0077] The first input terminal of the first redundant current detection sub-unit 221 is connected to the first sampling point 1, and the second input terminal of the first redundant current detection sub-unit 221 is connected to the third sampling point 3;

[0078] The first input terminal of the second redundant current detection sub-unit 222 is connected to the first sampling point 1, and the second input terminal of the second redundant current detection sub-unit 222 is connected to the second sampling point 2;

[0079] The first input terminal of the third redundant current detection sub-unit 223 is connected to the second sampling point 2, and the second input terminal of the third redundant current detection sub-unit 223 is connected to the third sampling point 3.

[0080] According to some embodiments, the first redundant current detection sub-unit 221, the second redundant current detection sub-unit 222, and the third redundant current detection sub-unit 223 can be used to detect the working state of the current detection circuit.

[0081] In some embodiments, as Figure 2 shown, the first redundant current detection sub-unit 221 includes a first voltage comparator, the second redundant current detection sub-unit 222 includes a second voltage comparator, and the third redundant current detection sub-unit 223 includes a third voltage comparator; among them,

[0082] When the current detection circuit is in normal operation, the first voltage U13 output by the first voltage comparator is equal to the sum of the second voltage U12 output by the second voltage comparator and the third voltage U23 output by the third voltage comparator.

[0083] It should be noted that if the first voltage U13 output by the first voltage comparator is not equal to the sum of the second voltage U12 output by the second voltage comparator and the third voltage U23 output by the third voltage comparator, it indicates that at least one of the resistance values of R12, R13, and R23 is abnormal, and a fault occurs in the current detection circuit. For example, the connection of at least one of the first sampling point 1, the second sampling point 2, and the third sampling point 3 is disconnected.

[0084] In summary, for the current detection circuit provided by the embodiment of the present invention, by setting the first sampling point, the second sampling point, and the third sampling point on the shunt sampling resistor, the current detection unit can perform current sampling based on the first sampling point and the third sampling point, can also perform current sampling based on the first sampling point and the second sampling point, and can also perform current sampling based on the second sampling point and the third sampling point; since the first resistance value between the first sampling point and the third sampling point is equal to the sum of the second resistance value between the first sampling point and the second sampling point and the third resistance value between the second sampling point and the third sampling point, therefore, the current sampling range between the first sampling point and the second sampling point and the current sampling range between the second sampling point and the third sampling point are both greater than the current sampling range between the first sampling point and the third sampling point. Compared with the current sampling range between the first sampling point and the third sampling point, the current detection range of the current detection circuit is improved.

[0085] According to the embodiment of the present invention, the present invention also provides an electronic device.

[0086] The electronic device includes: the current detection circuit as shown in any one of the foregoing embodiments.

[0087] In summary, for the electronic device provided by the embodiment of the present invention, by using the above current detection circuit, the current detection range of the current detection circuit can be improved.

[0088] In addition, the word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be understood as being advantageous compared to other aspects or designs. Instead, the use of the word exemplary is intended to present concepts in a concrete manner. As used herein, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X applies A or B" is intended to mean any arrangement in a natural inclusive arrangement. That is, if X applies A; X applies B; or X applies both A and B, then "X applies A or B" is satisfied in any of the foregoing instances. Additionally, unless otherwise specified or clear from the context referring to the singular form, the articles "a" and "an" as used in this application and the appended claims are generally understood to mean "one or more".

[0089] Similarly, although the present utility model has been shown and described with respect to one or more implementations, those skilled in the art will envision equivalent variations and modifications after reading and understanding this specification and the accompanying drawings. The present utility model includes all such modifications and variations and is limited only by the scope of the claims. Specifically with respect to the various functions performed by the components (e.g., elements, resources, etc.) described above, unless otherwise indicated, the terms used to describe such components are intended to correspond to any component (functionally equivalent) that performs the specific function of the described component, even if not structurally equivalent to the structure of the present utility model. Additionally, although a particular feature of the present utility model may have been invented with respect to only one of several implementations, such a feature may be combined with one or more other features of other implementations as may be desired and advantageous for any given or particular application. Further, with respect to the use of "comprises", "has", "includes", "with", or variations thereof in the detailed description or claims, such terms are intended to be inclusive in a manner similar to the term "comprising".

[0090] After considering the specification and practicing the invention of the present utility model, those skilled in the art will readily conceive of other embodiments of the present utility model. This application is intended to cover any variations, uses, or adaptations of the present utility model that follow the general principles of the present utility model and include known common knowledge or conventional technical means in the technical field of the present utility model that have not been invented by the present utility model. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present utility model are pointed out by the following claims.

[0091] It should be understood that the present utility model is not limited to the exact structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the present utility model is limited only by the appended claims.

Claims

1. A current detection circuit, characterized in that: include: Shunt sampling resistor and current detection unit; wherein, The shunt sampling resistor is provided with a first sampling point, a second sampling point and a third sampling point, and a first resistance value between the first sampling point and the third sampling point is equal to the sum of a second resistance value between the first sampling point and the second sampling point and a third resistance value between the second sampling point and the third sampling point; The current detection unit is connected to the first sampling point, the second sampling point and the third sampling point respectively.

2. The current detection circuit according to claim 1, characterized in that: The shunt sampling resistor includes a substrate; wherein, The first sampling point, the second sampling point and the third sampling point are all arranged on the substrate; A hollow area is provided on the substrate, and the hollow area is used to adjust the proportion of the second resistance value and the third resistance value in the first resistance value.

3. The current detection circuit according to claim 2, characterized in that: The substrate comprises a first material region and a second material region; wherein, The first sampling point, the second sampling point and the third sampling point are all connected to the second material area; The hollow area is arranged in the first material area; The electrical conductivity of the second material region is lower than the electrical conductivity of the first material region.

4. The current detection circuit according to claim 3, characterized in that: The second material region is arranged in the middle of the first material region, and the second material region divides the first material region into a first sub-region and a second sub-region, the first sampling point is arranged in the first sub-region and connected to the first end of the second material region, the second sampling point is arranged in the second sub-region and connected to the first end of the second material region, and the third sampling point is arranged in the second sub-region and connected to the second end of the second material region.

5. The current detection circuit according to claim 3, characterized in that: The material corresponding to the first material region is copper, and the material corresponding to the second material region is alloy.

6. The current detection circuit according to claim 2, characterized in that: The ratio of the second resistance value and the third resistance value to the first resistance value is determined by at least one of the following factors: The area of ​​the hollowed-out region; The position of the hollowed-out area; The shape of the hollow area.

7. The current detection circuit according to claim 1, characterized in that: The current detection unit includes a first current detection subunit, a second current detection subunit and a third current detection subunit; wherein, The first input end of the first current detection subunit is connected to the first sampling point, and the second input end of the first current detection subunit is connected to the third sampling point; The first input terminal of the second current detection subunit is connected to the first sampling point, and the second input terminal of the second current detection subunit is connected to the second sampling point; The first input terminal of the third current detection subunit is connected to the second sampling point, and the second input terminal of the third current detection subunit is connected to the third sampling point.

8. The current detection circuit according to claim 7, characterized in that: The current detection unit further includes a first redundant current detection subunit, a second redundant current detection subunit and a third redundant current detection subunit; wherein, The first redundant current detection subunit, the second redundant current detection subunit and the third redundant current detection subunit are used to detect the working state of the current detection circuit.

9. The current detection circuit according to claim 8, characterized in that: The first redundant current detection subunit includes a first voltage comparator, the second redundant current detection subunit includes a second voltage comparator, and the third redundant current detection subunit includes a third voltage comparator; wherein, When the current detection circuit is in normal operation, the first voltage output by the first voltage comparator is equal to the sum of the second voltage output by the second voltage comparator and the third voltage output by the third voltage comparator.

10. An electronic device, characterized in that: include: A current detection circuit as claimed in any one of claims 1 to 9.

Images