JP5223398B2 - Resistor circuit and resistance value adjusting method for the resistor circuit - Google Patents

Description

  The present invention relates to a resistance value adjusting method for a resistance circuit that can change the series resistance value by cutting one of the resistors connected in parallel by laser or electrical stress. Resistance circuits whose resistance values are adjusted by this method are used in constant voltage generation circuits and voltage detection circuits, and these circuits are mounted on, for example, semiconductor integrated circuits including analog electronic circuits.

  FIG. 7 is a circuit diagram illustrating an example of a voltage detection circuit. Reference numeral 15 denotes an operational amplifier. A reference voltage generating circuit 13 is connected to an inverting input terminal of the operational amplifier 15 and a reference voltage Vref is applied. The voltage of the terminal to be measured input from the input terminal (Vin) 23 is divided by the voltage dividing resistors 11 (Rt and RT) and 12 (Rb) and input to the non-inverting input terminal of the operational amplifier 15. The output of the operational amplifier 15 is output to the outside through the output terminal 19. In this voltage detection circuit 20, when the voltage of the terminal to be measured is high and the voltage divided by the voltage dividing resistors 11 and 12 is higher than the reference voltage Vref, the output of the operational amplifier 15 maintains “H”, When the voltage at the terminal to be measured drops and the voltage divided by the voltage dividing resistors 11 and 12 becomes lower than the reference voltage Vref, the output of the operational amplifier 15 becomes “L”.

  FIG. 8 is a circuit diagram showing an example of a constant voltage generation circuit. A constant voltage generating circuit 9 is provided in order to stably supply power from the DC power supply 5 to the load 7. The constant voltage generating circuit includes an input terminal 11 to which the DC power supply 5 is connected, a reference voltage generating circuit (Vref) 13, an operational amplifier 15, and a P-channel MOS transistor (hereinafter abbreviated as PMOS) 17 constituting an output driver. , Voltage dividing resistors R1 and R2 and an output terminal (Vout) 19 are provided. In the operational amplifier 15 of the constant voltage generating circuit 9, the output terminal is connected to the gate electrode of the PMOS 17, the reference voltage Vref is applied from the reference voltage generating circuit 13 to the inverting input terminal, and the output voltage Vout is applied to the non-inverting input terminal by the resistor R1. And the voltage divided by R2 are applied, and the divided voltage of the resistors R11 and R12 is controlled to be equal to the reference voltage Vref.

  In general, in the voltage detection circuit shown in FIG. 7 and the constant voltage generation circuit shown in FIG. 8, the reference voltage Vref from the reference voltage generation circuit fluctuates due to variations in the manufacturing process. A resistor RT whose resistance value can be adjusted is provided in the voltage dividing resistor to adjust the resistance value of the voltage dividing resistor. As this type of voltage dividing resistor, the resistance value of the voltage dividing resistor is adjusted by using a resistance circuit capable of adjusting the resistance value by cutting a fuse.

  FIG. 9 is a circuit diagram showing a conventional resistor circuit constituting a voltage dividing resistor. Resistance elements Rb, n + 1 (n is a positive integer) setting resistors RT1, RT2,..., RTn, and a resistor Rt are connected in series. .., RTn are connected in parallel with fuses f1,..., Fn corresponding to the respective setting resistors. Such a resistance circuit is disclosed in Patent Document 1 and the like.

  In such a resistance circuit, a desired series resistance value can be obtained by cutting arbitrary fuses f1,..., Fn with a laser beam. In this case, by making the resistance values of the fuses f1,..., Fn smaller than the resistance values of the set resistance elements RT1,. .

  When the resistance circuit of FIG. 9 is applied to the voltage dividing resistors R11 and R12 of the constant voltage generation circuit of FIG. 8, for example, the resistance element Rb end is grounded, the resistance element Rt end is connected to the drain of the PMOS 17, and the resistance elements Rb, A terminal node L between RT1 is connected to the non-inverting input terminal of the operational amplifier 15.

Further, when the resistor circuit of FIG. 9 is applied to the voltage dividing resistors R11 and R12 of the voltage detection circuit of FIG. 7, for example, the resistor element Rb end is grounded, the resistor element Rt end is connected to the input terminal 23, and the terminal node L is connected to the non-inverting input terminal of the operational amplifier 15. In these cases, the voltage dividing resistor R11 is constituted by Rb, and the voltage dividing resistor R12 is constituted by Rt, setting resistors RT1,..., RTn and fuses f1,.
JP 2003-37179 A

  In the resistor circuit shown in FIG. 9, a predetermined fuse is cut in order to adjust the resistance value. However, manufacturing variations occur in the semiconductor manufacturing process. When the resistance value is adjusted by cutting the fuse corresponding to the bit, the total error may exceed the correction amount by cutting the fuse. For example, as shown in FIG. 6, when the manufacturing error is 10%, the correction amount ΔV of bit 1 is 8, the correction amount ΔV4 of bit 2 is 4, the correction amount ΔV of bit 3 is 2, and the correction amount of bit 1 Let ΔV be 1. The respective errors are 0.8, 0.4, 0.2, and 0.1. When the fuse is cut up to bit 3, the total error becomes 1.4, and the correction amount in the next bit 1 is exceeded, and there is a problem that correction cannot be performed.

  The object of the present invention is to solve the above-mentioned conventional problems, and takes into account errors due to manufacturing variations, and by adjusting the resistance values including those errors, a highly accurate resistance value is obtained. It is an object to provide a method for adjusting a resistance circuit.

The resistor circuit of this invention, a plurality of resistors are connected in series, and each resistor is connected to a resistance value correcting resistor group in which a cutting fuse is connected in parallel, and a plurality of resistors are connected in series to each resistor. The body includes an error correction resistor group in which cutting fuses are connected in parallel, and the resistance value correction resistor group and the error correction resistor group are connected in series to adjust the resistance value. The fuse is cut from the resistance correction resistor group, and the error correction resistor fuse corresponding to the error is cut from the error correction resistor group according to the error value of the manufacturing variation of the resistor. A resistance circuit ,
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
The resistance value of each resistor in the error correction resistor group is set to the error of the resistance value of the corresponding resistor in the resistance value correction resistor group .

According to the resistance adjustment method of the resistance circuit of the present invention, a plurality of resistors are connected in series, and a resistance value correcting resistor group in which a cutting fuse is connected in parallel to each resistor, and a plurality of resistors are connected in series. Each resistor is provided with an error correcting resistor group in which a cutting fuse is connected in parallel. The resistance value correcting resistor group and the error correcting resistor group are connected in series to adjust the resistance value. To select the resistor for cutting the fuse from the resistance value correcting resistor group, obtain the error of the selected resistor, and cut the fuse of the resistor having a large resistance value from the selected resistor Then, before cutting the large resistor fuse, compare the obtained error with the allowable error range, and if it exceeds the allowable range, correct the error from the error correction resistor group. Select a resistor for the fuse and cut the fuse of this resistor Te, a resistance value adjustment method of the resistor circuit you correct the error,
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
The resistance value of each resistor in the error correction resistor group is set to the error of the resistance value of the corresponding resistor in the resistance value correction resistor group .

Also, the resistance adjustment method of the resistance circuit is such that a plurality of resistors are connected in series, a resistance value correcting resistor group in which a cutting fuse is connected in parallel to each resistor, and a plurality of resistors are connected in series. Each resistor includes an error correction resistor group in which a cutting fuse is connected in parallel, and the resistance value correction resistor group and the error correction resistor group are connected in series to adjust the resistance value. Therefore, the trimming code is obtained, the smallest bit among the resistors whose resistance value correction resistors are larger than the total error is obtained, the fuse of the corresponding minimum bit is cut, and the error amount is obtained from the error correction resistor group. select a correction to the error correction resistor, a resistance value adjustment method of the resistor circuit you correct the error by cutting the fuses of the resistor,
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
The resistance value of each resistor in the error correction resistor group is set to the error of the resistance value of the corresponding resistor in the resistance value correction resistor group .

  According to the present invention, before the total error exceeds the correction amount that can be corrected by the resistor for correcting the resistance value, the error can be adjusted by the error correcting resistor, including errors in manufacturing variations of the resistor. Therefore, it is possible to provide a resistance circuit that can be adjusted with high accuracy.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated in order to avoid duplication of description. FIG. 1 is a circuit diagram showing an embodiment of a resistance circuit used in the present invention.

  As shown in FIG. 1, a resistance value correcting resistor group 1 and an error correcting resistor group 2 are connected in series. In the resistance value correcting resistor group 1, a plurality of resistors R1, R2,..., Rn,... Rm are connected in series, and the resistors R1, R2,. f2, ..., fn, ..., fm are connected in parallel. In the error correction resistor group 2, a plurality of error correction resistors Ra1,..., Ram are connected in series, and a cutting fuse fa1,. It is connected.

  In this embodiment, the resistance value correcting resistor group 1 is connected to the top-side resistor Rt, and the resistance value is set so as to decrease in a binary number in order from the top side. The resistor R1 on the top side resistor Rt side corresponds to the bit 1 (B1), and the resistance value decreases in a binary number to m resistors R1 up to the resistor Rm for the bit m (Bm). R2, ..., Rm are connected in series.

  The error correction resistor group 2 is connected in series between the resistance value correction resistor group 1 and the bottom resistor Rb. The error correction resistors Ra1,..., Ram are configured to have, for example, a 10% resistance of the resistance value correction resistor corresponding to the error.

  When adjusting the resistance value, it is mounted on a circuit using a resistance circuit and actually operated, and a trimming code for adjusting the resistance is obtained online, and the code is converted into a binary number. Corresponding bit cutting fuses f1, f2,..., Fn-1... Fm are selected according to the trimming code converted into binary numbers. The corresponding fuses f1, f2,..., Fn-1,.

  The correction of the resistance value when the embodiment of the resistor circuit of FIG. 1 is applied to the voltage dividing resistors R11 and R12 of the voltage detection circuit of FIG. 7 will be described. An embodiment of the voltage detection circuit will be described with reference to FIGS. For example, the resistance element Rb end is grounded, the resistance element Rt end is connected to the terminal 23, and the terminal node L between the resistance elements Rb and RT is connected to the non-inverting input terminal of the operational amplifier 15. The voltage dividing resistor R11 is Rt, resistance value correcting resistors R1, R2,..., Rm, error correcting resistors Ra1,... Ram, and cutting fuses f1, f2,. .., Fan and the voltage dividing resistor R12 is composed of Rb.

  When adjusting the divided voltage input from the terminal node L to the non-inverting input terminal of the operational amplifier 15, the trimming code T can be obtained from the following equation (1).

T = (Rt + Rb) × (Vset / Vmes−1) / Rt
Here, Vset is a detection voltage setting value of the voltage detection circuit, Vmes is an input voltage value at the input terminal 23 at which the output of the operational amplifier 15 set and changed before the fuse is blown is inverted from “H” to “L”, for example. is there.

  The trimming code T obtained by the above equation is converted into a binary number, and the detection voltage is set to the set voltage by cutting the fuse of the bit resistor corresponding to the resistance correction resistors R1, R2,. Become.

  In the description of this embodiment, the correction amount is obtained by ΔV, and the correction amounts corresponding to the correction bits are also set to ΔV1, ΔV2,... ΔV as shown in FIGS. Since the correction amount ΔVn and the correction resistor Rn have the following relationship, if the reference voltage Vref and the correction amounts ΔVn and Rb are given, the resistance value of Rn of the correction resistor can be obtained.

  ΔVn = (Rn / Rb) × Vref

  As shown in FIGS. 5 and 6, an error occurs in each correction amount in the manufacturing process. In this embodiment, the error is determined in advance based on actual manufacturing variations in mass production and variations expected from experience from the process layout. For example, when the error is 10%, a value of 10% of the correction amount Δn becomes the error αn.

  As described above, the trimming code is obtained, and the resistance value is adjusted so that the detection voltage becomes the set voltage by cutting the fuse of the corresponding bit. However, there is also an error in the correction resistor. This error may cause an error that cannot be handled by the LSB bit even if the fuse of the predetermined bit is cut. In this case, there is a problem that the accuracy deteriorates due to this error. This problem will be described with reference to FIGS.

  In order to simplify the description, a case where the correction bit is 4 bits will be described as an example below. The correction amount Δ is 16. For each correction amount, bit 1 is 8, bit 2 is 4, bit 3 is 2, and bit 1 (LSB) is 1. The error was 10%.

  FIG. 2 shows a case where all the errors are −10%. By cutting the fuse of each bit and correcting bit 4, the correction amount is designed to be within “1” within the range of LSB. However, as shown in FIGS. 2, 4 and 6, the total error after processing bit 4 is 1.5. For this reason, the correction scheduled in design cannot be performed.

  Therefore, in the present invention, in consideration of this error, processing is performed so that the error of the shortage is compensated by using the error correction resistors Ra1... Ram.

  In this embodiment, the total error of the correction amount is obtained based on the calculated trimming code. That is, each total error is obtained when the corresponding bit is cut. As shown in FIG. 5, the total error of the correction amount Δn is α1 + α2 +.

  In this embodiment, the minimum bit that satisfies total error (Errn) <correction amount Δn is obtained. In the example of FIG. 6, the error is 1.4 and the correction amount is 2 for 3 bits. Further, the correction amount in the case of 4 bits is 1, and this error exceeds an allowable range that can be handled by the next correction amount. That is, the obtained total error is within the error tolerance range that can be handled by the next correction amount. Comparing the permissible ranges of this error and determining whether or not the permissible range is exceeded, finds the minimum bit that satisfies total error (Errn) <correction amount Δn.

  In the case of 4 bits shown in FIG. 4, the minimum bit that satisfies the total error (Errn) <correction amount Δn is 3 bits. Therefore, after the 3-bit fuse is cut, the total error Ernn is corrected. The error correction amount by the error correction resistors Ra1... Ram is within a range of 1.7 which is ½ of the total error (1.4) to (total error correction amount + processing bit correction amount). Select a bit.

  The error correction resistors Ra1,..., Ram corresponding to the error correction amount are selected, and the corresponding cutting fuses fa1,. The error correction resistors Ra1,..., Ram correspond to the error, for example, in the case where each of the resistance correction resistors Ra1,. What is necessary is just to comprise a bit. In this case, the error correction bit corrects the error by cutting the fuse of the error correction resistors Ra1... Ram of the bits up to the calculated minimum bit. By this error correction, correction can be performed within the range of the correction amount of the resistance value correcting resistor to be selected next.

  In this 4-bit example, as shown in FIG. 4, after the 3-bit processing, correction within the 4-bit, that is, LSB range can be performed by the error correction bit processing.

  FIG. 3 shows a case where the errors are all + α (10%). Then, the target value is exceeded before 4-bit processing. Therefore, even in such a case, if the 4-bit fuse is cut, the accuracy becomes worse. Therefore, if the 4-bit error correction fuse is used to correct the error α4, the 4-bit fuse is not cut. Good.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

It is a circuit diagram which shows one Embodiment of the resistance circuit used for this invention. It is a figure for demonstrating the adjustment method of the resistance circuit of this invention. It is a figure for demonstrating the adjustment method of the resistance circuit of this invention. It is a figure which shows the relationship between a total error when a 3-bit process is performed, and a correction amount. It is a figure which shows the relationship between a bit, correction amount (DELTA), an error, and a total error. It is a figure which shows the relationship between a bit, correction amount (DELTA), an error, and a total error. It is a circuit diagram which shows an example of a voltage detection circuit. It is a circuit diagram which shows an example of a constant voltage generation circuit. It is a circuit diagram which shows the conventional resistance circuit which comprises a voltage dividing resistor.

Explanation of symbols

1 resistance value correcting resistor group, R1, R2,..., Rn,... Rm resistor, f1, f2,..., Fn cutting fuse, 2 error correcting resistor group, Ra1,. Resistor, fa1,..., Fan cutting fuse.

Claims (3)

A plurality of resistors are connected in series, a resistance value correcting resistor group in which a cutting fuse is connected in parallel to each resistor, and a plurality of resistors are connected in series, and each resistor is connected to a cutting fuse Are connected in parallel, and the resistance value correcting resistor group and the error correcting resistor group are connected in series, and the resistance value correcting resistor group is used to adjust the resistance value. A resistor circuit in which the fuse of the error correction resistor corresponding to the error is cut from the error correction resistor group in accordance with the error value of the variation in manufacturing of the resistor .
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
A resistance circuit characterized in that the resistance value of each resistor in the error correction resistor group is set to an error in the resistance value of the resistor in the corresponding resistance value correction resistor group . A plurality of resistors are connected in series, a resistance value correcting resistor group in which a cutting fuse is connected in parallel to each resistor, and a plurality of resistors are connected in series, and each resistor is connected to a cutting fuse Are connected in parallel, and the resistance value correcting resistor group and the error correcting resistor group are connected in series, and the resistance value correcting resistor group is used to adjust the resistance value. Select the resistor to cut the fuse from, select the error of the selected resistor, cut the fuse of the resistor with the large resistance value from the selected resistor, and then connect the fuse with the large resistor Before cutting, compare the obtained error with the allowable error range.If the error exceeds the allowable range, select the error correction resistor that corrects the error from the error correction resistor group. by cutting the fuse, correct the error resistance circuit resistance A settling method,
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
A resistance value adjusting method, wherein the resistance value of each resistor in the error correcting resistor group is set to an error in the resistance value of the corresponding resistor in the resistance value correcting resistor group . A plurality of resistors are connected in series, a resistance value correcting resistor group in which a cutting fuse is connected in parallel to each resistor, and a plurality of resistors are connected in series, and each resistor is connected to a cutting fuse Are connected in parallel, the resistance correction resistor group and the error correction resistor group are connected in series, and a trimming code is obtained to adjust the resistance value, Find the smallest bit among the resistors whose resistance value correction resistor is larger than the error, cut the fuse of the corresponding minimum bit, and then select the error correction resistor that corrects the error from the error correction resistor group. , a resistance value adjustment method of the resistor circuit you correct the error by cutting the fuses of the resistor,
The number of resistors in the resistance value correcting resistor group is the same as the number of resistors in the error correcting resistor group, and each resistor in the resistance value correcting resistor group and each resistor in the error correcting resistor group And
A resistance value adjusting method, wherein the resistance value of each resistor in the error correcting resistor group is set to an error in the resistance value of the corresponding resistor in the resistance value correcting resistor group .

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