Resistor circuit and current detection circuit including said resistor circuit

Abstract

To provide a resistance circuit with a small area, which has low temperature dependence and can adjust a resistance value in a wide range from a high resistance value to a low resistance value, and a current detection circuit including the resistance circuit.SOLUTION: A resistance circuit 100 includes a reference resistor R0, a series variable resistor group 10, and a parallel variable resistor group 20 connected between a first terminal 1 and a second terminal 2, the series variable resistance group 10 includes N (N is an integer of 1 or more) parallel variable resistance units RP (N) connected in series with each other, each of the N parallel variable resistors units includes a resistor and a trimming element connected in parallel with this resistor, the parallel variable resistance group 20 includes M series variable resistance units RS (M) connected in parallel to each other (M is an integer of 1 or more), and each of the M parallel variable resistors units includes a resistor and a trimming element connected in series with this resistor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a resistor circuit and a current detection circuit including the resistor circuit. [Background technology]

[0002] Regarding the resistor circuit of a semiconductor integrated circuit, there is a technology in which an insulating layer is provided on a silicon substrate, and a polysilicon layer formed on the insulating layer is used as a resistor element. It is known that the temperature dependency of the resistance value of the polysilicon used as the resistor element varies depending on the dose amount when impurities are ion-implanted into the polysilicon (for example, see Patent Document 1).

[0003] Therefore, in order to obtain a polysilicon resistor element with low temperature dependency, the dose to the polysilicon layer must be controlled within a certain range. On the other hand, the sheet resistance value of polysilicon (resistance value per area) depends on the dose. Therefore, the sheet resistance value of a polysilicon resistor with low temperature dependency falls within a certain range.

[0004] Furthermore, when the constant voltage output circuit is formed by a semiconductor integrated circuit, for example, the resistance value of the resistor circuit is changed by trimming using a trimming element, and the voltage division ratio of the voltage divider circuit is set to a desired value.

[0005] Specifically, when the resistance value of a unit resistor is 1R, resistors such as 1 / 16R, 1 / 8R, 1 / 4R, 1 / 2R, and 1R are connected in series, and fuses are provided in parallel with each resistor. By arbitrarily cutting these fuses in the trimming process during manufacturing, the combined resistance of the entire resistor circuit can be set to the desired resistance value. By setting the resistance value of each resistor connected in parallel to the fuse to the nth power of 2 of the unit resistor (n is a consecutive integer), a resistor circuit with a desired resistance value can be obtained within a range of almost continuous resistance values. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-21909 A Summary of the Invention [Problem to be solved by the invention]

[0007] When realizing a current detection circuit using a semiconductor integrated circuit, current sensing is performed by measuring the voltage generated by passing a current through a resistor circuit for current detection as a method for detecting currents in the range of a few milliamperes (mA) to a few hundred mA. In addition to having a small temperature dependency of resistance value, such a resistor circuit for current detection is required to have a resistance value that can be adjusted with high precision over a wide range from high resistance value to low resistance value according to the current value to be detected.

[0008] However, in the case of a conventional resistor circuit whose resistance value is variable, in order to adjust the resistance value with precision, it is necessary to reduce the minimum resistance value of the resistor connected in parallel with the fuse. As described above, in a resistor element made of polysilicon, the sheet resistance value is constant when the temperature dependency is small, so the resistance value of the unit resistor cannot be arbitrarily reduced.

[0009] Techniques for reducing the minimum resistance value of a resistor circuit include, for example, a technique for increasing the number of resistors connected in parallel and a technique for shortening the length L of a unit resistor and widening the width W of the unit resistor.

[0010] However, when applying technology to increase the number of resistors connected in parallel, to achieve a resistance value of n smaller than the resistance value of 1R of a unit resistor, i.e., smaller resistance values ​​such as 1 / 32R, 1 / 64R, and 1 / 128R, a configuration in which 32, 64, and 128 resistive elements are connected in parallel is required, respectively. Since such a configuration in which resistive elements are connected in parallel includes a very large number of resistive elements, the circuit area becomes large, which in turn leads to an increase in the cost of the semiconductor chip.

[0011] Furthermore, when the resistance value of a unit resistor is reduced by adopting a technology to shorten the length L of the unit resistor and widen the width W of the unit resistor, the number of series resistors increases in order to adjust the resistance value of the entire resistor circuit to a higher resistance value. In this case, too, the circuit area increases, leading to an increase in the cost of the semiconductor chip.

[0012] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a resistance circuit that has little temperature dependency, can adjust the resistance value almost continuously over a wide range from high resistance values ​​to low resistance values, and has a small circuit area, and a current detection circuit that includes such a resistance circuit. [Means for solving the problem]

[0013] A resistor circuit according to an embodiment of the present invention is a resistor circuit having a variable resistance value, which is connected between a first terminal and a second terminal, and includes a reference resistor, a series variable resistor group connected in series with the reference resistor, and a parallel variable resistor group connected in parallel with the reference resistor, wherein the series variable resistor group has N parallel variable resistor units connected in series with each other, the Nth parallel variable resistor unit has an Nth resistor and an Nth trimming element connected in parallel with the Nth resistor, and the parallel variable resistor group has M series variable resistor units connected in parallel with each other, the Mth series variable resistor unit has an Mth resistor and an Mth trimming element connected in series with the Mth resistor, and both M and N are integers equal to or greater than 1. Then, the resistance value of the reference resistor is R 0 The combined resistance of the reference resistor and the parallel variable resistor group is R para The smallest resistance value among the resistance values ​​of the resistors included in the N parallel variable resistor units is R 1min The largest resistance value among the resistance values ​​of the resistors included in the M series variable resistor units is R 2max , the inequality in formula (1) is satisfied.

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[0014] According to the present invention, it is possible to provide a resistor circuit that has little temperature dependency, has a resistance value that can be adjusted almost continuously over a wide range from high resistance values ​​to low resistance values, and has a small area, and a current detection circuit that includes such a resistor circuit. [Brief description of the drawings]

[0015] [Figure 1] 1 is a circuit diagram showing a generalized configuration of a resistor circuit (N parallel variable resistor units, M series variable resistor units) according to an embodiment of the present invention. FIG. [Diagram 2] 3 is a circuit diagram showing a configuration example of a parallel variable resistor unit in the resistor circuit of the present embodiment. FIG. [Diagram 3] 3 is a circuit diagram showing a configuration example of a series variable resistor unit in the resistor circuit of the present embodiment. FIG. [Figure 4] FIG. 2 is a circuit diagram showing a specific configuration example (five parallel variable resistance units, five series variable resistance units) of the resistance circuit of the present embodiment. [Diagram 5] 13 is a table for explaining the number of resistors in a specific configuration example (parallel variable resistor units: 5, series variable resistor units: 5) of the resistor circuit of this embodiment. [Figure 6] 11 is a table illustrating the number of resistors in a resistor circuit of a comparative example. [Figure 7] 1 is a circuit diagram showing a configuration example of a current detection circuit including a resistor circuit according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A resistor circuit and a current detection circuit including the resistor circuit according to embodiments of the present invention will be described below with reference to the drawings.

[0017] FIG. 1 is a circuit diagram showing a generalized configuration of a resistance circuit 100 (including N parallel variable resistance units and M series variable resistance units, where N and M are both integers equal to or greater than 1) which is an example of a resistance circuit according to this embodiment.

[0018] The resistor circuit 100 includes a first terminal 1, a second terminal 2, a reference resistor R0, a series variable resistor group 10 connected in series with the reference resistor R0, and a parallel variable resistor group 20 connected in parallel with the reference resistor R0.

[0019] The reference resistor R0 is a resistive element including a polysilicon layer having a length L and a width W, and having a first end R0a and a second end R0b at both ends. of The resistance element of the reference resistor R0 is composed of a single resistance element or a plurality of resistance elements connected in series or in parallel.

[0020] Here, a resistor element formed from the same polysilicon layer as the reference resistor R0 and having the same length L and width W as the reference resistor R0 is referred to as a "unit resistor." Furthermore, the dose of ion implantation during manufacture of the polysilicon layer is adjusted so that the ideal temperature dependency is zero.

[0021] The series variable resistor group 10 includes a first end 10a connected to the first terminal 1, N parallel variable resistor units RP(1) to RP(N), and a second end 10b connected to a first end R0a of the reference resistor R0.

[0022] The N parallel variable resistance units RP(1) to RP(N) are connected in series, in order from the first end 10a to the second end 10b, as follows: parallel variable resistance unit RP(1), parallel variable resistance unit RP(2), ... (omitted) ..., parallel variable resistance unit RP(N-1), and parallel variable resistance unit RP(N).

[0023] The parallel variable resistor group 20 includes a first terminal 20a connected to a first terminal R0a of the reference resistor R0, M series variable resistor units RS(1) to RS(M), and a second terminal R0b connected to the reference resistor R0. Second end 20b It is equipped with the following:

[0024] The M series variable resistance units RS(1) to RS(M) are connected in parallel between a first end 20a and a second end 20b, with the series variable resistance unit RS(1), the series variable resistance unit RS(2), ... (omitted) ..., the series variable resistance unit RS(M-1) and the series variable resistance unit RS(M). Since the first end 20a and the second end 20b are connected to the first end R0a and the second end R0b, respectively, each of the series variable resistance units RS(1) to RS(M) is also connected in parallel with the reference resistance R0.

[0025] The overall resistance value of the resistor circuit 100 between the first terminal 1 and the second terminal 2 is determined by a composite resistance consisting of a reference resistor R0, a series variable resistor group 10, and a parallel variable resistor group 20. As described below, the parallel variable resistor units RP(1) to RP(N) and the series variable resistor units RS(1) to RS(M) each have a trimming element. Each of the parallel variable resistor units RP(1) to RP(N) and the series variable resistor units RS(1) to RS(M) is configured to be able to adjust the resistance value by setting the trimming element to a connected or disconnected state.

[0026] Figure 2 shows the parallel variable resistor unit RP( X ) is a circuit diagram showing a configuration example. N parallel Variable Resistor Unit RP (1)~RP(N) are resistor R1 [1]~R1[N] and resistor R1 [1]~R1[N] Trimming element T1 connected in parallel with [1]~T1 That is, the Xth parallel variable resistor unit RP(X) has a resistor R1[X] as a resistor and a trimming element T1[X] as a trimming element connected in parallel with the resistor R1[X], where X is an integer satisfying 1≦X≦N. It is.

[0027] Parallel variable resistor unit RP( X ) is connected to the trimming element T1[ X ] and the first end of resistor R1[ X ] and the first end of the parallel variable resistor unit RP(X The other terminal of the trimming element T1[ X ] and the second end of resistor R1[ X ] and a second end of the

[0028] Here, resistor R1[ X ] is composed of one unit resistor or multiple unit resistors connected in series or parallel. X ] is an element that can be switched from a connected state to a non-connected state, such as a fuse. The fuse is in a connected state in the initial state before the trimming process. The resistance value of the fuse is X ] is sufficiently small compared to the resistance of the connected fuse and resistor R1[ X The combined resistance of these resistors approximately equals the resistance of the fuse.

[0029] In the trimming process, the trimming element T1[ X ] is disconnected, i.e., the fuse is blown, the fuse X ] is much higher than the resistance of the fuse and resistor R1[ X ] is the combined resistance of resistor R1[ X ] is almost equal to the resistance value of the trimming element T1[ X ] depending on the connection or disconnection state of the parallel variable resistor unit RP( X ) resistance value is changed.

[0030] Figure 3 shows the serial variable resistor unit RS( X ) is a circuit diagram showing a configuration example. M series variable resistor units RS (1)~RS(M) are resistor R2 [1]~R2[M] and resistor R2 [1]~R2[M] Trimming element T2 connected in series with [1]~T2[M]That is, each of the X-th series variable resistor units RS(X) has a resistor R2[X] as a resistor and a trimming element T2[X] as a trimming element connected in series with the resistor R2[X], where X is an integer satisfying 1≦X≦M. It is.

[0031] Series variable resistor unit RS( X ) is connected to the trimming element T2[ X ] is connected to the first end of the trimming element T2[ X ] is connected to the second end of resistor R2[ X ] is connected to the first end of resistor R2[ X ] two The end is a series variable resistor unit RS( X ) is connected to the other terminal.

[0032] Here, resistor R2[ X ] is composed of one unit resistor or multiple unit resistors connected in series or parallel. X ] is an element that can be switched from a connected state to a non-connected state, for example a fuse. The resistance value of the fuse is resistor R2[ X ] is sufficiently small compared to the resistance value of trimming element T2[ X ] and resistor R2[ X The combined resistance of Resistor R2[X] The resistance value is almost the same.

[0033] In the trimming process, the trimming element T2[ X ] is disconnected, i.e., the fuse is blown, the fuse X ] is much higher than the resistance of the fuse and resistor R2[ X ] is the combined resistance of resistor R2[ X ] resistance value It has a much higher resistance than In this way, the fuse processing (cutting) or non-processing, that is, the trimming element T2 [ X ] depending on the connection or disconnection state of the series variable resistor unit RS( X) resistance value is changed.

[0034] The resistor circuit 100 is preferably configured so that the resistance value can be adjusted with high precision over a wide range from high to low resistance values. In order to make the resistance value adjustable with high precision over a wide range from high to low resistance values, the resistor circuit 100 is preferably configured to satisfy the following formula (1). In the following formula (1), R0 is the resistance value of the reference resistor R0, R para is the combined resistance of the reference resistor R0 and the parallel variable resistor group 20 before trimming, R 1min is resistor R1 [1]~R1 [N] Resistance Value The smallest resistance value among 2max is resistor R2 [1]~R2 [M] Resistance Value The largest resistance value among them.

[0035]

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[0036] According to the resistor circuit 100 according to the above formula (1), the adjustment accuracy does not deteriorate in the range of resistance values ​​that can be obtained after a specific trimming. That is, the resistance value can be adjusted almost continuously and accurately in a wide range.

[0037] From the viewpoint of suppressing an increase in the area of ​​the resistance circuit 100, it is effective to reduce the overlap of the adjustment ranges of the resistance values ​​of the series variable resistor group 10 and the parallel variable resistor group 20. In consideration of suppressing the circuit area of ​​the resistance circuit 100 within an appropriate range, it is preferable that the resistance circuit 100 is configured to satisfy the following formula (2). Note that R0 and R para and R 1min is the same as the above formula (1).

[0038]

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[0039] According to the resistor circuit 100 in accordance with the above formula (2), it is possible to reduce the overlap of the adjustable ranges of the resistance values ​​of the series variable resistor group 10 and the parallel variable resistor group 20, and therefore it is possible to suppress an increase in the circuit area.

[0040] If the resistor circuit 100 is configured to satisfy both the above formula (1) and the above formula (2), it is more preferable than the resistor circuit 100 configured to satisfy either the above formula (1) or the above formula (2). The resistor circuit 100 that satisfies both the above formula (1) and the above formula (2) can adjust the resistance value with high precision over the entire wide range from high resistance values ​​to low resistance values, and can further suppress an increase in the circuit area.

[0041] The adjustable range of the resistance value of the resistor circuit 100 is the range from when the trimming elements T1[1] to T1[N] and the trimming elements T2[1] to T2[M] are all connected to when they are all disconnected (disconnected). 100min , the maximum resistance value is R 100max If the resistance of the fuse is ignored, R 100min and R 100max are expressed by the following formula (3) and formula (4), respectively, where X is an integer satisfying 1≦X≦N.

[0042]

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[0043] The resistor circuit 100 has a resistance value R 100min From R 100max The adjustable range of the resistance value of the resistor circuit 100 is determined by the parallel variable resistor unit RP( 1)~( N) or series variable resistor unit RS( 1)~( This can be easily changed by changing the design value of M, which represents the number of resistors (M), and the number of each resistor.

[0044] The combined resistance of the resistor circuit 100 is R 2maxSince trimming the series variable resistor unit including this resistor enables adjustment of the resistance value to the smallest degree of precision, if you want to adjust the resistance value with even finer precision, this can be achieved by increasing the resistance value of resistor R2[M] in the series variable resistor unit RS(M).

[0045] In conventional resistor circuits, the adjustment accuracy was improved by reducing the resistance value of the resistor connected in parallel with the fuse, but since the resistance value of the fuse and the resistance value of the resistor are close to each other, an error occurs in the change in resistance value due to trimming. In addition, the fuse is ion-implanted with a different dose than the polysilicon resistor, or is formed by salicide, so the temperature dependence of the resistance value is different. As a result, the temperature dependence of the resistor circuit is also worsened.

[0046] In contrast, in the resistor circuit 100 having the above-described configuration, the series variable resistor unit RS( X Resistance in R2[X] However much the resistance adjustment accuracy is improved, the fuse T2[X] Resistance value and resistance R2[X] Since the resistance values ​​of the resistor circuit 100 do not approach each other, no significant error occurs in the change in the resistance value, and no deterioration in temperature dependency occurs. Therefore, the resistor circuit 100 can arbitrarily increase the accuracy of adjusting the resistance value of the resistor circuit 100.

[0047] FIG. 4 is a circuit diagram showing an example of the configuration of a resistor circuit 100a, which is a specific example of the resistor circuit 100. As shown in FIG.

[0048] The resistor circuit 100a is a resistor circuit 100 that satisfies the above-mentioned formula (1) and is configured with N=5 and M=5. In the resistor circuit 100a, the reference resistor R0 is configured by connecting resistors R01 and R02 in parallel. The resistance value R0 of the reference resistor R0, which is the parallel connection of resistors R01 and R02, is expressed as 1 / 2R.

[0049] The resistance values ​​of the resistors of each parallel variable resistor unit in the series variable resistor group 10 are 4R in RP(1), 2R in RP(2), 1R in RP(3), 1 / 2R in RP(4), and 1 / 4R in RP(5).

[0050] The resistance values ​​of the resistors of each series variable resistor unit in the parallel variable resistor group 20 are 1R in RS(1), 2R in RS(2), 4R in RS(3), 8R in RS(4), and 16R in RS(5).

[0051] In the resistor circuit 100a including the series variable resistor group 10 and the parallel variable resistor group 20, the left side of the above formula (1) is calculated to be about 0.011, and the inequality of the above formula (1) is satisfied. The left side of the above formula (2) is calculated to be about 0.14, and the inequality of the above formula (2) is also satisfied. Therefore, the resistor circuit 100a is configured to be able to adjust the resistance value with high precision over a wide range from high resistance values ​​to low resistance values, and further to suppress an increase in the circuit area.

[0052] 5 and 6 are tables illustrating the numbers of resistors in the resistor circuit 100 and the comparative example resistor circuit.

[0053] Here, the resistance circuit of the comparative example (not shown) is a resistance circuit having 10 variable resistance units, which is the same number as the resistance circuit 100, and configured to have the same minimum adjustment accuracy as the resistance circuit 100a. To be more specific, the resistance circuit of the comparative example is configured with variable resistance units RcP(1) to RcP(10) corresponding to the parallel variable resistance units RP(1) to RP(10) instead of the series variable resistance group 10 and the parallel variable resistance group 20 compared to the resistance circuit 100a. Also, the resistance circuit of the comparative example is configured with a reference resistor Rc0 having a resistance value approximately equal to the resistance value of the combined resistance of the reference resistor R0 and the parallel variable resistor group 20 instead of the reference resistor R0 compared to the resistance circuit 100a.

[0054] In the resistor circuit 100a, the total number of resistors between the reference resistor R0, the parallel variable resistor units RP(1)-RP(5), and the series variable resistor units RS(1)-RS(5) is 46 (see FIG. 5). On the other hand, in the resistor circuit of the comparative example, the total number of resistors between the reference resistor Rc0 and the variable resistor units RcP(1)-RcP(10) is 265 (see FIG. 6).

[0055] Comparing the resistor circuit 100a with the resistor circuit of the comparative example, the total number of resistors in the resistor circuit 100a (46 resistors) can be reduced to approximately 17%, or roughly one sixth, of the total number of resistors in the resistor circuit of the comparative example (265 resistors). In other words, the resistor circuit 100a can reduce the circuit area of ​​the resistor elements to roughly one sixth of the circuit area of ​​the resistor elements in the resistor circuit of the comparative example, thereby suppressing an increase in the cost of the semiconductor chip.

[0056] Moreover, the resistance circuit 100a has a minimum resistance value of 1 / 4R. In contrast, the resistance circuit of the comparative example has a minimum resistance value of 1 / 128R. Comparing the minimum resistance value (=1 / 128R) of the resistance circuit of the comparative example with the minimum resistance value (=1 / 4R) of the resistance circuit 100a, the minimum resistance value of the resistance circuit of the comparative example is 1 / 32 times the minimum resistance value of the resistance circuit 100a, which is very small, so that a large error is more likely to occur in the resistance value of the resistance circuit after trimming due to the influence of the fuse resistance value than in the resistance circuit 100a. That is, the resistance circuit 100a can reduce the error in the resistance value of the resistance circuit 100a after trimming compared to the resistance circuit of the comparative example.

[0057] Next, a current detection circuit including the resistor circuit of this embodiment will be described. FIG. 7 is a circuit diagram showing an example of the configuration of a current detection circuit 200, which is an example of the current detection circuit of this embodiment.

[0058] The current detection circuit 200 includes a power supply terminal 3, a ground terminal 4, a sense output terminal 5, a resistance circuit 100 which is an example of the resistance circuit of this embodiment, a load 101, a sense transistor 110, an output transistor 111, a PMOS transistor 112, a gate drive circuit 120, and a current sense amplifier 121. The current detection circuit 200 is configured to detect an output current Iout flowing through the output transistor 111, and to supply to the sense output terminal 5 a voltage converted by a current proportional to the detected output current Iout flowing through the resistance circuit 100.

[0059] Next, the connections of the current detection circuit 200 will be described. The sense transistor 110 has a source connected to the power supply terminal 3, a gate connected to the output terminal of the gate drive circuit 120 and the gate of the output transistor 111, and a drain connected to the source of the PMOS transistor 112 and the inverting input terminal (-) of the current sense amplifier 121. The output transistor 111 has a source connected to the power supply terminal 3, and a drain connected to one terminal of the load 101 and the non-inverting input terminal (+) of the current sense amplifier 121.

[0060] The other terminal of the load 101 is connected to the ground terminal 4. The output terminal of the current sense amplifier 121 is connected to the gate of the PMOS transistor 112. The drain of the PMOS transistor 112 is connected to the first terminal of the resistor circuit 100 and the sense output terminal. The second terminal of the resistor circuit 100 is connected to the ground terminal 4.

[0061] Next, the operation of the current detection circuit 200 will be described. An output current Iout flows through the load 101 between the source and drain of the output transistor 111. The current sense amplifier 121 controls the gate voltage of the PMOS transistor 112 so that the voltage of the inverting input terminal and the voltage of the non-inverting input terminal match.

[0062] The gate voltage of the PMOS transistor 112 is controlled so that the voltage of the inverting input terminal and the voltage of the non-inverting input terminal match, and as a result, the drain voltage of the sense transistor 110 matches the drain voltage of the output transistor 111. Since the source, gate, and drain voltages of the sense transistor 110 and the output transistor 111 match, a sense current Isense proportional to the output current of the output transistor 111 flows through the sense transistor 110.

[0063] The sense current Isense flows through the resistance circuit 100 via the PMOS transistor 112, and a sense voltage Vsense is generated across the resistance circuit 100 and is output to a sense output terminal 5 as an output terminal. The sense voltage Vsense is a voltage obtained by current-voltage conversion of the sense current Isense by the resistance of the resistance circuit 100. Therefore, the sense voltage Vsense is proportional to the output current Iout, and the output current can be detected by reading the sense voltage Vsense from outside.

[0064] The accuracy of current detection in the current detection circuit 200 is affected by manufacturing variations. The main factors that affect the current detection accuracy are the variation in the resistance value of the resistor circuit 100, the relative variation in the characteristics of the sense transistor 110 and the output transistor 111, and the offset voltage between the input terminals of the current sense amplifier. By including the resistor circuit 100, the current detection circuit 200 can expand the current detection range while suppressing the circuit area, and since the variation in the resistance value is compensated for, it is possible to generate a sense voltage Vsense with good accuracy.

[0065] In addition, the accuracy of current detection can be improved by trimming the resistor circuit 100 so as to offset the relative variation in the characteristics of the sense transistor 110 and the output transistor 111 and the influence of the offset voltage between the input terminals of the current sense amplifier.

[0066] It should be noted that the present invention is not limited to the above-described embodiment, and in the implementation stage, it may be implemented in various forms other than the above-described examples, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention.

[0067] For example, the order of connections of resistors and trimming elements may be changed as long as it does not affect the combined resistance before and after trimming.

[0068] For example, in addition to the series variable resistor group 10 and the reference resistor R0, another resistor circuit having a different resistance value composed of the same unit resistors may be connected in series with the resistor circuit 100 between the first terminal 1 and the second terminal 2.

[0069] The trimming elements T1[1] to T1[N] and the trimming elements T2[1] to T2[M] are not limited to fuses. The trimming elements T1[1] to T1[N] and the trimming elements T2[1] to T2[M] may be any elements that can be switched from a connected state to a non-connected state, for example, MOS (Metal Oxide Semiconductor) transistors.

[0070] The MOS transistors serving as the trimming elements T1[1] to T1[N] and the trimming elements T2[1] to T2[M] can be switched between a connected state (on) and a disconnected state (off) by controlling the gate voltage. Note that N, which represents the number of parallel variable resistor units RP(N), and M, which represents the number of series variable resistor units RS(M), do not necessarily need to be different numbers, and may be the same number as long as they are integers equal to or greater than 1.

[0071] The above-described embodiments and their variations are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0072] 1 First terminal 2 Second terminal 10 Series variable resistors 20 parallel variable resistors R0 Reference resistor RP(N) Parallel variable resistor unit RS(M) Series variable resistor unit R1[N], R2[M] resistance T1[N], T2[M] trimming elements 100, 100a resistor circuit 200 Current detection circuit 111 Output transistor 5 Sense output terminal (output terminal)

Claims

1. A resistor circuit having a variable resistance value, connected between a first terminal and a second terminal, comprising: a reference resistor; a series variable resistor group connected in series with the reference resistor; and a parallel variable resistor group connected in parallel with the reference resistor; the series variable resistor group includes N parallel variable resistor units connected in series with each other, each of the N parallel variable resistor units includes a resistor and a trimming element connected in parallel with the resistor; the parallel variable resistor group includes M series variable resistor units connected in parallel to each other, each of the M series variable resistor units includes a resistor and a trimming element connected in series to the resistor; The M and N are each an integer of 1 or more, The resistance value of the reference resistor is R ０ The combined resistance of the reference resistor and the parallel variable resistor group is R ｐａｒａ , the smallest resistance value among the resistance values ​​of the resistors included in the N parallel variable resistor units is R １min The largest resistance value among the resistance values ​​of the resistors included in the M series variable resistor units is R ２max , the inequality in equation (1) is satisfied.

1. A resistor circuit comprising: [0010]

2. The resistance value of the reference resistor is R ０ The combined resistance of the reference resistor and the parallel variable resistor group is R ｐａｒａ , the smallest resistance value among the resistance values ​​of the resistors included in the N parallel variable resistor units is R １min The resistor circuit according to claim 1 , wherein the inequality in formula (2) is satisfied when [0025]

3. the resistor circuit is formed of a semiconductor including a polysilicon layer; 3. The resistor circuit according to claim 1, wherein the reference resistor, the resistors of the N parallel variable resistor units, and the resistors of the M series variable resistor units are formed from the same polysilicon layer included in the semiconductor.

4. A current detection circuit for detecting a current flowing through an output transistor, A resistor circuit according to any one of claims 1 to 3; the output transistor; A current detection circuit characterized in that the resistor circuit has a resistance value adjusted so that a current proportional to the current flowing in the output transistor flows, and a voltage generated across the resistor circuit is supplied to an output terminal.

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