JPS5954326A - Correcting device of series resistance array - Google Patents

Abstract

PURPOSE:To correct the dispersion in resistive elements by themselves, by detecting an error voltage at a ramp voltage generating circuit and a comparator and switching a correcting resistance array with a switch. CONSTITUTION:Both ends of the series resistance array 16 are connected to a reference voltage input terminal 11 via correcting resistance arrays 14, 15 comprising correcting resistors and switches, and an optional voltage is outputted through any of the switches S1-Sn. To correct the linearity of the resistance array 16, a voltage and a reference voltage at points A, B of the resistance array 16 are applied to a comparator 22 via a switch group 21 and they are compared with an output of the ramp voltage generating circuit 23. Further, a reference clock is counted by a counter 25 with the compared value and the correcting amount is obtained from the count value at each switch. The switches of the correcting resistance array 14, 15 are switched based on the correcting amount.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention improves the conversion accuracy of the analog digital transformation] V', one circuit,
11 regarding the primary device.

Conventionally, in an analog to analog converter circuit using a resistor array, the value of each resistor is adjusted by a resistor trimming technique to reduce conversion errors caused by variations in resistance values. Performing such trimming (from L, high resolution 11H, BP 8:f♂
1;''], but this method has the disadvantage that it is necessary to accurately measure the resistance value of the resistors Al, . . . and that it takes time to adjust. be.

In view of the circumstances surrounding this invention: 11, using a resistor array, successive approximation type at 7'', tracking ratio 1+11
Type 2 analog/digital change 1°, '1 time 1i! 1′
Framed by J￥;, 11, (, resistance value (,, I et al' tatami 1〆 generated by -47) change j'L!n'', the difference is ヅ1 Key 81 of Sng'''-γ, there is no need to do it, 4 dimensions of the resistance value and ':) to ('・- rise occurring shift j(f37-,'!i difference to self hf + positive) Gain, replacement 11゛; IEJI can be improved (',)j pi 1
- Column 1i - (Anti-array correction 1 115 1; 1 ↓
(-4- means 1-1.)

Line up the month of January from this date.
,,,i・When it becomes clear, the next,l,is achieved.
For (1-1゛)゛゛〉〈〈〈〈〈〈〉〉〉〉〉〉〉〉〉〉〉〉〉〉〈〉〈〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〈〉
'Two:)Kika;l:+TwoCmo,',<"f-ノ)41@ Derived from the child/,,A L"dj'pressure'i)
1'k: "r-IK M about 1r mo, Rito-J-1 Otsutame (・, f mountain j-j, i!!, anti-Ashi'14.15 ter I (Sho Gerotomo (・2, ] 111 row 1I4'l'L
: The tenth point of the array (A.

B) Detect the error voltage of 1++! , pressure generation 1
In order to reduce the voltage at the erroneous point A and T3, the correction switches 5S+l''S+a+S21 to S23 in the correction resistor array 14.15 are set to J' ( This is to ensure that the switching iii control V is carried out.

Below is the gl of this invention! Explain example m with reference to three drawings.
Ru.

In Figure 1, 11.12 is the 1st. Second reference city: pressure input terminal, 13 is unknown voltage input terminal. 14.15 is a correction resistance array on the A side and the Low side, in which a plurality of series circuits of correction resistances and switches are connected in parallel. One end of the correction resistor array 14 is connected to the first reference i pressure input polarizer 1. One end is connected to the second reference voltage input terminal 12, and the other end (l) is connected to the other end of the series resistor array 716.
Connecting part of the resistive element and press the 2 μm, second reference 'input end''F77, x,? They are connected in common to one end of the comparator 18 through any one of Irr, T', Nia, I, :/-'fS, and ~Sn in parallel. In addition to this comparator 18, the unknown voltage input terminal 13 is connected to QW. And the said Con P.
The output \"11i, 1 of the converter 18 is the conversion control circuit 19
connected to. The conversion control circuit 79 (r, I, the above-mentioned switches Sl to Sn) is turned on in sequence to jQ+, and each switch is set to r.

The output from the comparator 18 is
``The data is sent to the output terminal ■).~Dn-1.

In order to digitally convert the unknown pressure V of the target resistor array x61-J-1 for such an analog-to-digital conversion, it is necessary to use it as a part that generates a reference voltage for comparison. 〒lYX means switch S.
It is desirable that the voltage change when -3 is turned on one after another is linear. However, if there is variation in resistance value between each resistor, it is not possible to obtain a favorable voltage change for l''.
), this circuit is provided with means for automatically correcting variations in the resistance value.

For example, the illustrated point A of the series resistor array 16.

Let point B be the correction point. These correction points A and B are the switch S
After passing through 3I and S32, the comparator 22
is connected to one input end of the tree. Also one switch 531
Switches 833, 834 are also provided in parallel to 1832, which connects one input 1. ! :, each 1st. second reference voltage input terminal 77,
It is connected between yk. switches S31 to 534i,
f,' is used as the resistance value variation detection switch group 21. Next, to the other input terminal of the converter 22, a lamp voltage suitable for the linear method is also inputted to the lamp voltage generating circuit 23.

The comparator 23 compares the output from the switch group 2 with the ramp 0 voltage, and inputs the comparison result to the counter and counter control circuit 25. This counter and counter control circuit 25 counts the clocks from the reference clock generation circuit 24 when the output of the comparator 22 is, for example, a high I7 level. The count value obtained by this counter and counter control circuit 25 is stored in the reno star 26. The correction calculation circuit 27 is a circuit that uses the count value to calculate the difference of 1t11j between the resistance value of the resistor array and the abrasive resistance value. The calculation result of the correction calculation circuit 27 is input to the correction switch circuit 28.
Is this the 28th correction switch circuit? Based on the correction ■ (resistance array 14, 1υ of the switch of 1.5 is performed 4 times, series 1J (resistance array 16
It is set so that the voltage Iff from the right resistor f changes constantly by +7.

One embodiment of the present invention is constructed as described above, and its operation will be explained next.

Now, for example, assume that layer 11 is at point A, and the button is used to detect whether or not the 'IIi pressure here is the desired (direct, &) level. A
Ideal point', :t br bone, 11, by the following relation QC, T 1 "1 can be obtained. Using the 21st ゛・, 1, i explanation J, first correspond to the lap ′ voltage X. te, J-, i'; Memi Ti, j pressure Vraf (-) to Vrpf (4)
II (min time i'r(T (+) at 1. The principle of point A; time 0 to t 't at which the voltage becomes 4 voltage υl is determined by the number of resistors in the resistor array. Therefore, , Vre
The integration time from f(-) to υ1 is 1. Then, t,
+/To −υ' / (Vrcf (4,)
The l'J4i system of rL, f (-)) is hl
ζStanding size.

By doing this, if you know the count number G at time t1 and the cock frequency, you can determine it in advance.

Next, find the actual voltage at point A. Karinku system f111
Circuit 25 &; I1, lamp city: Start the pressure generation circuit 23 and turn on the switch 833. Therefore, the reference voltage Vref(-) and the lamp's screaming pressure are inputted to the comparator 22, and both are compared and a point of agreement is obtained. For convenience of explanation, we will refer to this matching point as 0 in Figure 2.
This will be explained as a point in time. From this time point 0, the counter and counter fl+lJ control circuit 25d1 turns on the switch S31 connected to the point A.

From this point on, the lamp voltage and the low voltage at point A in the figure are input to the comparator 22 and compared. As shown in FIG. 2, the lamp voltage X increases over time,
tI, 1 at the moment! Suppose that it matches the actual voltage v/ at point A, which is 7. At this time, in the counter and counter control circuit 25, it is 1 from the time (), and '11 is 11 (: cycle time, dandruff count 1.).

Here, since the buried pressure at point A7)L pressure is υ1, dirt - v
I's d Wu difference? If the potential pressure is a, then h is two things.

Also, as shown in IK of pit 21, from time 0, 1/.

At that moment, Naoman looked up at Y and said, ``Tolt'! l at point i
, -) is assumed to be the error voltage Δ■(→,), which can be obtained by calculating the voltage value at time 10 from the previous counter 6r value by 8'l in advance. It will be done. Here the error is 715. The pressure ΔV(→) corresponds to the 'tE pressure applied to the correction resistor array 14. Now switch S1
2 is closed! At my father-in-law, if ΔV(→-) is approximately ±I,a
If there is a voltage corresponding to the voltage of
,' If the state where pressure is applied (n, switch Sll is closed), there will be an error at point A. 7. Error rlI,
IiE? ]'1? J 1 will be smaller than before.

, the above correction resistance A/-14 switch, ticket system fIll
There are 11 correction switch control times and 28 V each.

This correction switch control circuit 28 stores data corresponding to the negative 1■η error voltage Δ■(+) in the correction calculation -1 path 2.
7: A small amount is input. Then, the control circuit 28 controls the switch SX in the correction resistor A/-14 based on the data corresponding to the error voltage ΔV(+).
1 to SI3 will be controlled. In this switch control circuit 28, several types of conversion tables for switch control are stored corresponding to input data. So-〇, switch S11 to S+3
The on state of 4Je can be switched on or off by switching one by one, or by a combination.

The above explanation is based on the error at point A 〒b, pressure τ/, −υl
To correct, from time 0 to 119, t'1''Il
], then count the clocks, calculate the straight line extension Y shown in Figure 2 from the R1 number (forced to 11), and calculate the time, a'
]' Find the error voltage ΔV(+) at o, and generate the corresponding field data in the correction calculation circuit 27.'
Met. (Data t corresponding to the value of the counter,
Correction@:M: In the 1rjl path, the river 1 is stored in advance in a read-only memory, for example. ) Previous error voltage Δ■(+)υ'': This is used to switch and control the switches in the correction resistor array 14.

Next, the correction [[(switches 821 to S2 in the anti-array 15
In order to switch and control 1.3, a straight line extension W shown in FIG. 2 is assumed. , second base i'tp%: voltage vref (-3 side error voltage ΔV(-) can be found. It can be assumed that /, ), then the count value of Nori Rinta is 1 at time 0. ? Rikoto can do it. Therefore, a voltage corresponding to this error voltage ΔV(-) is also input to the correction switch control circuit 28. Accordingly, the correction switch control circuit 28 performs switching control of the switches 521-8 and 521-3 so as to reduce the error voltage τ'1-v.

The second operation; the situation is the error voltage υ'Xia at point A in the diagram -1
) 1 has been described, the correction operation at point A has been described, but if one point is 7 Jr. as shown in FIG. To know the full-scale characteristics of the resistor array voltage Z at a more detailed point in time, what is the best way to find out the error at multiple points? 1): Yes, if you use a pressure detector.

Therefore, at point B in FIG.
Corrections are made.

In this way, when error voltages are detected at multiple locations and the supplementary IE processing MP is performed, for example, as shown in FIG. 3, the envelope of the count for the lamp voltage X is 7! allb, 1C9
11 (Anti-array voltage characteristics can be obtained by matching the threads of ld. The difference between ΔV(+) and Δ■(-) is -!-LS
It is better to determine the envelope 7BM'c than to not exceed B. However, strictly speaking, the resistor array voltage characteristic corrected only once does not necessarily have ideal linearity.

Therefore, the above correction processing operation is repeated from the previous correction switch (B) to E, %j, and the new correction switch is turned off. By performing I control, as shown in Fig. 4, the ideal lamp voltage X with good linearity,
IJ (resistance to 7 rays' tonnage pressure'jlf property is brought closer to tjb (
The difference is 1'. 4th resistor array voltage! 1'(
('C(x IJ1 1 ノ; h+ , lci
, 19dl), (6a2, /h
2 + Ac2 +'d2), (/, 3, l
! b5.4c3) respectively show a situation in which the lamp voltage Xt= gradually approaches -ζ''.

In this way, the correction operation is performed every time the lamp 01h, the pressure is 3U, and 14=. ,/I) Conversion speed equivalent to converter, filr minute IA/L: converter 4I] High precision, high resolution A
7 x 1 switch can be used 2).

Kirani front suspension: correction su/(nochi j+, 1.l (jll
Times 11'F52 Rniyl l.

(d, % unknown human power 2 pressure Vin positive, pressure 17 (information is input from the conversion control circuit 19. unknown T1
The output price information is used in the correction switch control circuit 28 as conversion table switching information 7;111. That is, if the unknown input voltage is close to the voltage at time 00 in Figure 2, there is almost no false voltage in this vicinity, so there is no need to modify the correction resistor array, and the unknown voltage information is used as the judgment information. Use 1 fru. Furthermore, depending on the value of the unknown input voltage, it may be sufficient to modify either one of the correction resistor arrays 2, and the unknown voltage information is also used for this determination. Is this kind of correction necessary or unnecessary?
nt, 7E tube/N, and a range determination function is provided for t'1.
? :i, the unknown input voltage range can be expanded by l, and accurate conversion can be obtained.

The present invention is not limited to the above embodiments, and although the above description has been given as an example of application to an analog-to-digital converter, it can also be applied to a digital-to-analog converter. For example, if the switches S and -Sn are turned on in correspondence with the digital quantity, inputted to the voltage follower circuit, and -C outputted to rΣ etc. via the buffer circuit, a digital-to-analog conversion output can be obtained. In such a case as well, it is possible to correct the variations between the series resistor elements and obtain a high-quality conversion output by switching the correction resistor array i:il (jl l) in the same way as in the previous case. Furthermore, in the above embodiment, the reference clock generation circuit 24, the counter and counter control circuit 25, the register 26, the correction calculation circuit 27, and the correction switch control 11 former SUI 28 are used as the correction resistance array switching control means. However, this part can be modified in various ways.

For example, an A/D converter may be used that amplifies the output analog voltage of the comparator 22 itself and outputs the supplementary i [switch switching number 44] according to its level.
In this case, the configuration becomes simple.

As mentioned above, in this invention, even if the resistance value is distributed between the resistor array resistance elements of the i+;I and iFi columns,
It is possible to provide a correction device for a surface array resistor array, which eliminates the need for performing adjustment operations such as resistor trimming, enables self-correction, and improves conversion accuracy in analog to digital conversion.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention. Figures 2, 3, and 4 are circuit diagrams of the iCb circuit shown to explain an example of the operation of the circuit in Figure 1. FIG. )4,1. Evening...N+LI positive resistance array, Noro...
Series resistor array, 18.22...□Comparator, 1
9... Conversion control circuit, 23... Rump 0 voltage generation circuit, 24... Reference clock generation circuit, 2, 5... Counter and counter control circuit, 26... Register, 2
8... Correction switch control circuit.

Claims (5)

[Claims] (1) 1st on both ends. A series resistance array to which a second reference voltage is applied, and a correction resistance element and a correction switch connected in series between a part of the series resistance array and at least one of the reference voltages, each having a different resistance value. A correction resistor array having series circuits connected in parallel, and a comparator for comparing an arbitrary error detection point of the series resistor array with the lamp voltage. The IH column resistor array is characterized by comprising means for periodically detecting an error voltage between the error voltage and the actual voltage at the error detection point, and selectively controlling a correction switch in the correction resistor array. correction device. (2) The means for switching and controlling the correction switch includes:
The scope of the patent is characterized in that it has means for introducing the output of the comparator every time the lamp voltage occurs so as to sequentially change and control the state of the front correction switch every time the lamp voltage occurs. 2. A correction device for a series resistor array according to item 1. (3) The correction resistor array (l) is provided between one end of the series resistor array and the first reference voltage, and the voltage is provided between the other end of the series resistor array and the second reference voltage. Characteristics of the range of the first term of the range of 1q and 8IV of the series resistance A1/- of the ?+ii positive device. (4) means i, t for switching and controlling the correction switch;
Counts the reference clock according to the low level change of the output of the =+regulator ・A counter and counter control circuit that sends data to the register, and stores the contents of the register and the register in advance. a correction calculation circuit that generates data corresponding to the 6μ difference "rlf and pressure in accordance with predetermined contents; a correction switch control circuit that selectively switches the correction switch based on the output data of the correction calculation circuit; A correction device for a nearly single-row resistor array as claimed in claim 1, comprising/herein. (5) The correction switch control circuit 111 changes the analog-to-digital conversion to the unknown input voltage value 11:, and then changes the 1-way selection switching mode of the previous 6E correction switch! A correction device for a series resistor array according to claim 4, characterized in that: τ.