JPH11121694A - Reference voltage generating circuit and method for adjusting it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize dependency on temperature through trimming by comprising a resistance element and a bipolar transistor or diode, while a first variable means for changing the value of a first voltage and a second variable means for changing the value of a second voltage are provided. SOLUTION: A band gap reference(BGR) circuit 10 comprises a first operation amplifier 1, a second resistance element R2 connected, in series, between the output end of the first operation amplifier 1 and a ground electric potential, a first resistance element R1 and a first diode D1, and a third resistance element R3 connected, in series, between the output end of the operation amplifier 1 and the ground electric potential and a second diode D2. Related to the BGR circuit 10, a variable means for changing BGR output voltage VBGR is connected. Related to an output correction circuit 20, a second variable means for changing a correction output voltage Vref is connected. Thus, correction is so made as to decrease fluctuation of a voltage value of the BGR output voltage VBGR and temperature-dependency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference voltage generation circuit formed in a semiconductor device and a method of adjusting the reference voltage generation circuit, and more particularly to a reference voltage generation circuit having a band gap reference (BGR) circuit and a circuit for correcting the output voltage thereof. And a method for adjusting the output voltage thereof, and is applied to, for example, a reference voltage supply circuit of an analog / digital conversion circuit.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device, there is a case where a reference voltage generating circuit for generating a reference voltage having little dependency on temperature and power supply voltage is formed. In this case, the band gap value of silicon (1.20
A band gap reference (BGR) circuit that generates a reference voltage substantially equal to 5 V) is widely used.

[0003] Reference 1 (DF Hilbiber, 1964 ISSCC Dig
est of Technical Papers, vol.7, pp. 32-33) Reference 2 (RJ Widlar, IEEE Journal of Solid-State)
Circuits, vol.SC-6, pp. 2-7, Feb. 1971) Reference 3 (KE Kuijk, IEEE Journal of Solid-State C)
ircuits, vol. SC-8, pp. 222-226, 1973) FIG. 10 shows a basic configuration of a BGR circuit of Conventional Example 1.

In FIG. 10, Q1, Q2, and Q3 are NP
N transistors, R1, R2, and R3 are resistance elements, I is a constant current source, and Vref is an output voltage (reference voltage). This B
The GR circuit has a forward voltage VF (having a negative temperature coefficient) of a PN junction diode or a base-emitter PN junction (hereinafter referred to as a diode) of a bipolar transistor whose collector and base are connected to each other (diode connection). ) And a voltage several times the voltage (having a positive temperature coefficient) of the difference between the forward voltages VF of the diodes whose current densities have been changed, so that a temperature coefficient of about 1.25 V is output, which is almost zero. Is configured.

If the characteristics of the transistors Q1 and Q2 are uniform, the base-emitter voltages of the transistors Q1, Q2 and Q3 are changed to VBE1, VBE2 and VBE3, and the transistors Q1 and Q2.
, Q2 are represented by I1 and I2, the emitter voltage V2 of the transistor Q2 becomes V2 = VBE1-VBE2 = VT.ln (I1 / I2), and Vref = VBE3 + (R3 / R2) V2 = VBE3 + (R3 / R2) VT * ln (I1 / I2).

The first term in the above equation has a temperature coefficient of approximately -2 mV / ° C., while the second term has a temperature coefficient of (R 3 / R 2) (k / q) ln (I 1 / I 2). Is zero if k=1.38.times.10@23 J / K q=1.6.times.10@-19 C. (R3 / R2) ln (I1 / I2) = 23. 2

If V BE3 = 0.65 V at 23 ° C.,
Vref in the above equation is Vref = 0.65 + 0.6 = 1.25 V, which is the bandgap value of silicon (1.2
05).

FIG. 11 shows an example of a BGR circuit of the second conventional example. The principle of operation of this BGR circuit is PN
The temperature difference between the temperature coefficient (negative) of the forward voltage of the junction diode (base-emitter voltage of the bipolar transistor) and the forward voltage (base-emitter voltage of the bipolar transistor) of the PN junction diode with the changed current density By making the linear sum of the coefficient (positive) zero, the temperature dependency of the BGR output voltage VBGR is eliminated.

As shown in FIG. 11, the linear coefficient of the temperature coefficient is determined by a plurality of resistance elements R1, R2,
It depends on the resistance ratio of R3 and, for example, the number ratio of a plurality of diode-connected bipolar transistors D1 and D2.
The BGR can be obtained at the output terminal of the operational amplifier circuit (operational amplifier) 1.

In reality, when the threshold voltage and the resistance value of the MOS transistor used in the operational amplifier (first operational amplifier 1) in the BGR circuit and the saturation current of the bipolar transistor vary due to variations in the manufacture of the semiconductor device,
These variations are amplified and the BGR output voltage VBGR varies.

For this reason, as shown in FIG.
An output correction circuit for correcting the voltage value (absolute value) by multiplying the output voltage VBGR of the circuit by the resistance ratio may be used.

The conventional output correction circuit has a BGR output voltage V
A second operational amplifier 2 whose BGR is input to a (+) input terminal as a reference voltage, and a voltage (output voltage) of the output terminal of the second operational amplifier 2 between the output terminal of the second operational amplifier 2 and the ground potential Vss. Vref) and a variable resistance dividing circuit which can change the resistance dividing ratio.

This variable resistance dividing circuit includes a first resistance element Rd, a second resistance element Re, and a third resistance element Rf connected in series, and a fuse element connected in parallel to the third resistance element Rf. F. Then, the voltage at the connection node between the first resistance element Rd and the second resistance element Re (the divided voltage of the output voltage Vref) is input to the (-) input terminal of the second operational amplifier 2 as a feedback signal.

The output voltage Vref of the second operational amplifier 2
When the fuse element F is not cut, Vref = VBGR · (Rd + Re) / Re. When the fuse element 2 is cut, Vref = VBGR · (Rd + Re + Rf) / (Re + R)
f), the variation in the BGR output voltage VBGR can be absorbed by cutting the fuse element F and adjusting the resistance ratio.

However, if the resistance value and the saturation current of the bipolar transistor vary due to manufacturing variations, the BG
Since not only the voltage value of the R output voltage VBGR but also the temperature dependency changes, the BGR is calculated using a conventional output correction circuit.
Even if the voltage value of the output voltage VBGR is trimmed, the temperature dependency remains largely as shown in FIG.

[0016]

As described above, in the conventional BGR circuit, when the resistance value and the saturation current of the bipolar transistor vary due to manufacturing variations of the semiconductor device,
Since not only the absolute value of the BGR output voltage but also the temperature dependency changes, there is a problem that the temperature dependency remains even if the voltage value is trimmed.

An object of the present invention is to provide a reference voltage generating circuit which can minimize not only the absolute value of the BGR output voltage at a certain temperature but also its temperature dependency by trimming. Aim.

[0018]

A reference voltage generation circuit according to the present invention has a plurality of resistance elements and a plurality of bipolar transistors or diodes, and outputs a first voltage. Alternatively, the divided voltage is used as a first input voltage, a second voltage is output, and the second
An operational amplifier circuit that uses a divided voltage of the voltage as a second input voltage; first variable means for changing the value of the first voltage; and second variable means for changing the value of the second voltage Means.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment of a reference voltage generation circuit formed in a semiconductor device.

In FIG. 1, reference numeral 10 denotes a BGR circuit having a plurality of resistance elements and a plurality of bipolar transistors (diodes) diode-connected to generate a BGR output voltage VBGR, and 20 denotes a BGR output voltage VBGR multiplied by a resistance ratio. And an output correction circuit for correcting the voltage value (absolute value).

The configuration example of the BGR circuit 10 includes a first operational amplifier 1 and a second resistance element R2 connected in series between the output terminal of the first operational amplifier 1 and the ground potential Vss.
A first resistor element R1 and a first diode D1, and a third resistor element R3 and a second diode D2 connected in series between the output terminal of the first operational amplifier 1 and the ground potential Vss. I do. Then, the second resistance element R
The connection point n1 between the second resistance element R1 and the first resistance element R1 is input to the (-) input terminal of the first operational amplifier 1, and the connection point n2 between the third resistance element R3 and the second diode D2 is The signal is input to the (+) input terminal of the first operational amplifier 1.

The BGR circuit 10 further includes the BG
First variable means capable of changing the R output voltage VBGR is connected. As an example of the first variable means, one or a plurality of first fuse elements F1 are used, and one or more of the plurality of resistance elements R1 to R3 are selected according to the cut state / non-cut state. Is adopted in which the resistance value of the resistance element is changed.

That is, in this embodiment, a part of the first resistance element R1 and a part of the third resistance element R3 each have a plurality of division points, and the first fuse element is provided between adjacent division points. (For example, polysilicon fuse) F1 is connected. Thus, the first resistance element R1 is divided into, for example, two resistance elements R11 and R12, and the third resistance element R3 is divided into, for example, two resistance elements R31 and R32.

Thus, the desired first fuse element F
1 is controlled by, for example, laser light irradiation, so that the resistance of the first resistor R1 and the third resistor R
It is possible to change the resistance value of 3.

On the other hand, an example of the configuration of the output correction circuit 20 is as follows.
A second operational amplifier 2 in which the BGR output voltage VBGR (or a divided voltage thereof) is input to a (+) input terminal as a reference voltage, and a second operational amplifier 2 between the output terminal of the second operational amplifier 2 and the ground potential Vss. And a resistance dividing circuit for dividing the voltage (output voltage Vref) at the output terminal of the operational amplifier 2.

The resistor dividing circuit includes a fifth resistor R5
And the fourth resistance element R4 are connected in series, and the voltage at the connection node between the fifth resistance element R5 and the fourth resistance element R4 (the divided voltage of the output voltage Vref) is equal to that of the second operational amplifier 2.
(−) Input terminal as a feedback signal.

The output correction circuit 20 is further connected to a second variable means capable of changing the correction output voltage Vref. As an example of the second variable means,
There is provided a variable resistance dividing circuit which uses one or a plurality of second fuse elements F2 and is capable of changing a resistance dividing ratio of the resistance dividing circuit according to a cut state / non-cut state.

In this variable resistance dividing circuit, a part of the fourth resistance element R4 has a plurality of division points, and a second fuse element (for example, a polysilicon fuse) is provided between adjacent division points. ) F2 is connected. That is, the fourth resistance element R4 is, for example, two resistance elements R41,
It is divided into R42. This makes it possible to change the resistance value of the fourth resistance element R4 by controlling the cutting of the desired second fuse element F2 by, for example, laser beam irradiation.

In the reference voltage generating circuit shown in FIG. 1, the first variable means includes the BGR output voltage VBGR.
And the second variable means is set so as to minimize the difference between the output voltage Vref and a target value.

Next, the principle of adjusting the temperature dependency and the absolute value of the output voltage in the reference voltage generating circuit of FIG. 1 will be described. B
The input offset voltage of the first operational amplifier 1 in the GR circuit 10 is stabilized at dVin, the resistance ratio R2 / R1 is dx1, the resistance ratio R2 / R3 is dx2, and the saturation current ratio IS1 / IS2 of the diodes D1 and D2 is dn. When there is variation, the BGR output voltage VBGR deviates by dVBGR from the value when there is no variation.

DVBGR = ｛1+ (R2 / R1)｝ dVin + ｛γdx1 + (R2 / R1) (dx2 + dn)｝ kT / q (1) γ = (R2 / R1) ln ｛IS2 / R2 / IS1 / R3｝ (2) Here, IS1 and IS2 indicate the saturation currents of the diodes D1 and D2, respectively.

From the above equation (1), the resistance ratios R2 / R1, R2
It can be seen that when the / R3 and the saturation current ratio IS1 / IS2 vary, the BGR output voltage VBGR has a temperature dependency. Therefore, first, the resistance ratio R2 / R1 is set to dr1, the resistance ratio R2 / R
3 by dr2, and the values of dr1 and dr2 so as to minimize the absolute value of the temperature coefficient a, | γ (dx1 + dr1) + (R2 / R1) (dx2 + dr2 + dn) = a | Have decided. At this time, the BGR output voltage VBGR still varies by dVBGR = {1+ (R2 / R1)} dVin + akT / q (4).

Therefore, if the design value of the BGR output voltage VBGR is represented by VBGR "and the design value of the output voltage Vref of the output correction circuit 20 is represented by Vref", the target is Vref "= VBGR" / x3 (5) The resistance ratio x3 of R5 and R4 is shifted by dr3 to minimize | (VBGR "+ dVBGR) / (x3 + dr3) -VBGR" / x3 = (dVBGR-VBGR "dr3 / x3) / x3 | ... (6) I have to.

FIG. 2 shows an example of the temperature dependence of the output voltage Vref of the reference voltage generating circuit of FIG. As can be seen from the characteristics of FIG. 2, even if the resistance value and the saturation current of the bipolar transistor vary due to manufacturing variations, the BGR
It is possible to correct so that the fluctuation of the voltage value of the output voltage VBGR and the temperature dependency are reduced.

FIGS. 3A and 3B show an example of the cross-sectional structure and circuit connection (equivalent circuit) of the bipolar transistor used as the first diode D1 and the second diode D2 in FIG.

That is, an N-type well 32 is formed in a P-type substrate 31, and a P + diffusion layer 33 is formed in the N-type well 32. The layer 32a and the P + diffusion layer 31a for leading out the electrode of the P-type substrate 31 are connected. The PN junction between the P + diffusion layer 33 and the N-type well 32 is used as a diode.

The diodes D1 and D2 are:
One diode or a plurality of diodes connected in series or in parallel to each other may be used. <First Embodiment of Reference Voltage Generating Circuit> FIG. 4 shows a first embodiment of the reference voltage generating circuit of FIG.

The reference voltage generating circuit shown in FIG. 4 is different from the reference voltage generating circuit shown in FIG. 1 in that a probing pad for voltage measurement for trimming is connected to the BGR circuit 10. If the resistance element R1 is a plurality of resistance elements R
The point that it is divided into 11 to R14, the third resistor R3 is divided into a plurality of resistors R31 to R34, and the fourth resistor R4 is divided into a plurality of resistors R41 to R44. The differences are the same, and the others are the same.

That is, the reference voltage generating circuit of the first embodiment
A plurality of first diodes D1 connected in series or in parallel with each other, and a plurality of second diodes D2 connected in series or in parallel with each other;
A second resistor element R2 and a first resistor element R1 connected in series to the first diode D1 and connected to each other at a first connection point n1; and a second connection point to the second diode D2. a third resistor R3 connected in series with n2
A first operational amplifier 1 that receives a first voltage appearing at the first connection point n1 and a second voltage appearing at the second connection point n2 and outputs a third voltage; Voltage measuring means for measuring the first voltage, the second voltage and the third voltage, first variable means (for example, a first fuse element F1) for changing the third voltage, and an output correction circuit 20
And a second variable means (for example, a second fuse element F2) for changing the output voltage Vref of the output correction circuit 20. According to the three voltage values measured by the voltage measuring means, Thus, the third voltage is changed by the first variable means.

The voltage measuring means is connected to the first connection point n.
A first probing pad P1 and a second probing pad P2 connected to the first and second connection points n2, respectively; and a third probing pad P3 connected to the output terminal of the first operational amplifier 1. And
The voltage of each pad can be measured by an external tester (not shown).

FIG. 5 is a flowchart showing an example of a trimming method for voltage correction of the reference voltage generation circuit of the first embodiment shown in FIG. The outline of the trimming method shown in the flowchart of FIG. 5 is as follows. First, trimming is performed so as to minimize the temperature dependency of the BGR output voltage VBGR, and the output voltage value is further trimmed so as to minimize the difference from the target value. Thus, a reference voltage with small temperature dependence and small variation in absolute value is obtained.

Next, the trimming method shown in the flowchart of FIG. 5 will be described in detail. First, the first step S1
Then, the voltage value at each pad is measured by an external tester (not shown).

In the next step S2, the difference dVin between the two input voltages of the first operational amplifier 1 and the difference dVBGR between the measured value of the bandgap voltage and the design value are calculated. In the next step S3, the equation (1) at the temperature To at the time of voltage measurement is used.
Is the coefficient e e = dVBGR-{1+ (R2 / R1)} dVin · q / k when the second term is expressed as e · kTo / q.
Calculate To.

In the next step S4, a parameter set (dr1, dr2) for minimizing the temperature coefficient aa = | e + γ · dr1 + (R2 / R1) dr2 | defined by the above equation (3) is determined.

In the next step S5, the resistance ratio (R2 / R
1) and (R2 / R3) correspond to (R2 / R1
) + Dr1, (R2 / R3) + dr2.

In the next step S6, the variation d of the bandgap voltage after trimming defined by the above equation (4)
Calculate VBGR. In the next step S7, the expression (6)
The parameter dr3 for minimizing the difference between the target value and the design value Vref "of the output voltage Vref of the output correction circuit 20 is determined.

In the next step S8, trimming is performed so that the resistance ratio x3 of R5 and R4 is changed to x3 + dr3.
Step S5 can be trimmed at the same time as step S8 after steps S6 and S7. In this case, it is possible to blow the trimming fuse at a time.

<Embodiment 2 of Reference Voltage Generating Circuit> FIG.
2 shows a second embodiment of the reference voltage generating circuit of FIG. FIG.
4 is different from the reference voltage generating circuit shown in FIG. 4 in that the output correction circuit 20 is also connected to a probing pad for voltage measurement for trimming, and the other components are the same. Therefore, the same reference numerals as in FIG. 4 are used.

That is, the reference voltage generating circuit of the second embodiment
A plurality of first diodes D1 connected in series or in parallel with each other, and a plurality of second diodes D2 connected in series or in parallel with each other;
A second resistor element R2 and a first resistor element R1 connected in series to the first diode D1 and connected to each other at a first connection point n1; and a second connection point to the second diode D2. a third resistor R3 connected in series with n2
A first operational amplifier 1 that receives a first voltage appearing at the first connection point n1 and a second voltage appearing at the second connection point n2 and outputs a third voltage; And the second operational amplifier 2 that outputs the fourth voltage or the divided voltage thereof as the first input voltage, outputs the fourth voltage, and uses the fourth voltage or the divided voltage thereof as the second input voltage, Voltage measuring means for measuring the voltage, the second voltage, the third voltage and the fourth voltage, and variable means for changing the third voltage and the fourth voltage (for example, the first fuse element F1 And a second variable means using a second fuse element F2), and the variable means according to the four voltage values measured using the voltage measuring means. Changes the third voltage and the fourth voltage.

The voltage measuring means is connected to the first connection point n
A first probing pad P1 and a second probing pad P2 connected to the first and second connection points n2, respectively; and a third probing pad P3 connected to the output terminal of the first operational amplifier 1. A fourth probing pad P4 connected to the output terminal of the second operational amplifier 2, and a fifth probing pad P5 connected to the input terminal of the second input voltage of the second operational amplifier 2. And the voltage of each pad can be measured by an external tester (not shown).

FIG. 7 is a flowchart showing an example of a trimming method for voltage correction of the reference voltage generation circuit of the second embodiment shown in FIG. This flowchart is shown in FIG.
As compared with the flowchart of the first embodiment shown in FIG. 1, in step S11, the voltage value of the output terminal of the second operational amplifier 2 and the voltage value of the input terminal of the second input voltage are also measured.
In step S17, the difference ω between the design value Vref "of the output voltage Vref of the output correction circuit 20 and the target value defined by the following equation (8) is minimized in consideration of the temperature dependence of the second operational amplifier 2. To determine the parameter dr3
The other steps S12 to S16 and S18 are the same as steps S2 to S6 and S8 shown in FIG.

That is, assuming that the input offset voltage of the second operational amplifier 2 is dVin2 and the variation of the resistance division ratio x3 of R5 and R4 is dx3, VBGR + dVin2 = Vref (x3 + dx3) (7) The difference ω between the target value Vref "of the output voltage Vref of the circuit 20 and Vref when the resistance ratio x3 of R5 and R4 is shifted by dr3 is ω = [dVBGR- ｛Vref" (dx3 + dr3) / x3｝ + dVin2] / x3... (8), and the trimming may be performed with dr3 so as to minimize this ω.

In the description of the first embodiment,
In order to trim the temperature dependency of the BGR output voltage VBGR, two resistance elements R1 and R3 in the BGR circuit 10 are used.
Is changed, but the present invention is not limited to this. Even if the value of one resistor R2 in the BGR circuit 10 is changed,
It is possible to trim the temperature dependency of the GR output voltage VBGR.

That is, the above equation (3) can be modified as the following equation. By changing R2 / R1 by dr1, | c (dx1 + dr1) + (R2 / R1) (dx2 + d
n) = a |.

By changing R3 / R2 by dr2, | c.dx1 + (R2 / R1) (dx2 + dr2 + d
n) = a |.

By changing n by dr4, | c.dx1 + (R2 / R1) (dx2 + dn + dr4
) = A |.

Generally, A, B, and C are 0 or 1,
As a constant, at least one of A, B and C is 1, | c (dx1 + A.dr1) + (R2 / R1) (dx2
+ B.dr2 + dn + C.dr4) = a | so that dr1 or dr2 or d is minimized.
r4 or a combination thereof may be determined.

As can be seen from the above description, the method of adjusting the reference voltage generating circuit of the present invention can be implemented as described in the following examples. <Adjustment method 1 of reference voltage generation circuit> First resistance ratio x1,
A bandgap reference circuit having a first operational amplifier circuit for outputting a voltage dependent on the second resistance ratio x2 and the first saturation current ratio n;
Variable means for changing 1 (i) (1 = <i = <I), variable means for changing the second resistance ratio x2 by dr2 (j) (1 = <j = <J), and / or The saturation current ratio n of 1 is dr4 (k)
(1 = <k = <K) When adjusting the reference voltage generating circuit having a variable means for changing by x, when x1 fluctuates by dx1, x2 fluctuates by dx2, and n fluctuates by dn, A, B, and C take 0 or 1, and A, B,
X1 ln [x2 n] (dx1 + Adr1 (i)) + x1 (d
x2 + Bdr2 (j) + dn + Cdr4 (k)) so that dr1 (i), dr2 (j) and / or d
Determine r4 (k) and change x1 by dr1 (i), x2 by dr2 (j) and / or n by dr4 (k).

<Method 2 for Adjusting Reference Voltage Generating Circuit> A first operational amplifier circuit for outputting a first voltage dependent on the first resistance ratio x1, the second resistance ratio x2, and the first saturation current ratio n. A bandgap reference circuit having:
Means for changing the resistance ratio x1 of the second resistor by dr1 (i) (1 = <i = <I), and the second resistance ratio x2 by dr2 (j) (1 = <j = <J)
And the variable means for changing the first saturation current ratio n by dr4 (k) (1 = <k = <K), and the first voltage or the divided voltage thereof by the first means. A second operational amplifier circuit for inputting and outputting a second voltage dependent on the third resistance ratio x3, and for providing the third resistance ratio x3 as dr
3 (l) When adjusting the reference voltage generating circuit having variable means for changing by 1 (<l = <L), x1 fluctuates by dx1, x2 fluctuates by dx2, and n fluctuates by dn. When fluctuating, A, B, and C take 0 or 1;
X1 ln [x2 n] (dx1 + Adr1 (i)) + x1 (d
x2 + Bdr2 (j) + dn + Cdr4 (k)) dr1 (i), dr2 (j) and / or dr4 (k) are determined so as to minimize x1, and x1 is changed by dr1 (i). (i), x2 is changed by dr2 (i), and / or n is changed by dr4 (k), the amount of change in the first voltage and x1, x2, n and the first operational amplifier circuit. The first voltage (V) when the input offset voltage is zero
When the input offset voltage of the second operational amplifier circuit is dVin2 and x3 fluctuates by dx3, dV-V0 (dr3 (l) + dx3) / x3 + dVin2 is minimized. Is determined, and x3 is changed by dr3 (l).

<Third Embodiment of Reference Voltage Generating Circuit> In each of the first and second embodiments, a plurality of diodes connected in series or in parallel to each other may be used as the first diode D1. When a plurality of diodes connected in series or in parallel to each other are used as the second diode D2, one or a plurality of first fuse elements are used, and their cut / non-cut states are used. The temperature dependency of the reference voltage may be trimmed by using a variable means for changing the number of the diodes to be used according to the following.

FIG. 8 shows a third embodiment of the reference voltage generating circuit. The reference voltage generation circuit shown in FIG. 8 is basically different from the reference voltage generation circuit shown in FIG.
Are different from each other, and the other components are the same.

Specifically, one or a plurality of fuse elements are used as the first variable means, and are connected to the second diode D2 (or the first diode D1) according to the cut state / non-cut state. A configuration is adopted in which the number of diodes connected in parallel is changed.

That is, one fuse element (for example, polysilicon fuse) F1 and one diode D2a are connected in series with one end (connection point n2) of the diode D2 and the ground potential Vss in parallel with the diode D2. Connected to the fuse element F1 and the diode D2a.
Another fuse element F1 and another diode D2a are connected in series between the connection point of the second and the ground potential Vss in parallel with the diode D2a. Thereafter, the same connection is repeated a required number of times. I have.

Similarly, one fuse element (for example, a polysilicon fuse) F1 and one diode D1a are connected in series between one end of the diode D1 and the ground potential Vss in parallel with the diode D1. Further, another one fuse element F1 and one diode D1a are connected in parallel with the diode D1a between the connection point of the fuse element F1 and the diode D1a and the ground potential Vss.
Are connected in series, and thereafter, the same connection is repeated a required number of times.

Thus, it is possible to change the number of diodes connected in parallel with the diode D2 or D1 by controlling the cutting of the desired fuse element F1 by, for example, irradiating a laser beam.

<Embodiment 4 of Reference Voltage Generating Circuit> In the present invention, like the first embodiment shown in FIG. 1, a reference voltage generating circuit using a BGR circuit introduced by Kuijk The present invention can be similarly applied not only to a circuit but also to a reference voltage generating circuit using another BGR circuit.

FIG. 9 shows a second embodiment of the reference voltage generating circuit according to the present invention.
In the fourth embodiment, the present invention is applied to a reference voltage generating circuit including a BGR circuit introduced by Widlar of the above-mentioned Document 2 and an output correction circuit for amplifying the output voltage of the BGR circuit.
Is shown.

Also in the reference voltage generating circuit of the fourth embodiment, the resistance value of at least one of the three resistance elements R1 to R3 in the BGR circuit, or at least one of the three bipolar transistors Q1 to Q3 First variable means (for example, fuse element F1) for changing the base-emitter junction area of one transistor
, The temperature dependency of the reference voltage can be trimmed.

Further, by using the second variable means (for example, fuse element F2) for changing the resistance value of at least one of the two resistance elements R5 and R4 in the output correction circuit, the absolute value of the reference voltage can be reduced. Values can be trimmed.

[0070]

As described above, according to the present invention, trimming can be performed so as to minimize the temperature dependency of the output voltage of the bandgap reference circuit, and the difference between the trimmed output voltage value and the target value can be minimized. Thus, it is possible to provide a reference voltage generation circuit capable of generating a reference voltage that can be further trimmed to generate a reference voltage with small temperature dependency and small absolute value variation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a reference voltage generation circuit according to the present invention.

FIG. 2 is a characteristic diagram showing temperature dependence of an output voltage of the reference voltage generation circuit of FIG.

FIG. 3 is a sectional structure and circuit connection (equivalent circuit) of a bipolar transistor used as a diode in FIG.
FIG.

FIG. 4 is a circuit diagram showing a first embodiment of the reference voltage generation circuit of FIG. 1;

5 is a flowchart showing an example of a trimming method for voltage correction of the reference voltage generation circuit shown in FIG.

FIG. 6 is a circuit diagram showing a second embodiment of the reference voltage generating circuit of FIG. 1;

FIG. 7 is a flowchart illustrating an example of a trimming method for voltage correction of the reference voltage generation circuit illustrated in FIG. 6;

FIG. 8 is a circuit diagram showing a third embodiment of the reference voltage generating circuit of FIG. 1;

FIG. 9 is a circuit diagram showing a second embodiment of the reference voltage generation circuit of the present invention.

FIG. 10 is a circuit diagram showing a first conventional example of a reference voltage generation circuit.

FIG. 11 is a circuit diagram showing a conventional example 2 of a reference voltage generation circuit.

12 is a characteristic diagram showing the temperature dependence of the output voltage of the circuit of FIG.

[Explanation of symbols]

 Reference numeral 10: BGR circuit, 20: output correction circuit, 1, 2: operational amplifier, D1, D2: diode element, R1 to R5: resistance element, F1, F2: fuse element, P1 to P5: probing pad.

Claims (16)

[Claims] A bandgap voltage generating circuit having a plurality of resistive elements and a plurality of bipolar transistors or diodes and outputting a first voltage; and a first input voltage, wherein the first voltage or a divided voltage thereof is a first input voltage. And outputs the divided voltage of the second voltage to the second voltage.
An operational amplifier circuit as an input voltage, a first variable means for changing the value of the first voltage, and a second variable means for changing the value of the second voltage. Characteristic reference voltage generation circuit. 2. The reference voltage generation circuit according to claim 1, wherein said first variable means is means for changing a resistance value of one or a plurality of resistance elements of said plurality of resistance elements. Characteristic reference voltage generation circuit. 3. The reference voltage generating circuit according to claim 1, wherein said first variable means is means for changing the number of said bipolar transistors or diodes used. 4. The reference voltage generating circuit according to claim 1, wherein said second input voltage is a resistance divided voltage obtained by dividing said second voltage by a resistor. 5. The reference voltage generating circuit according to claim 1, wherein said first variable means is set so as to minimize the temperature dependency of said first output voltage, and said second variable means is A reference voltage generating circuit set to minimize a difference between the second output voltage and a target value. 6. A bandgap voltage generating circuit having a plurality of resistive elements and a plurality of bipolar transistors or diodes and outputting a first voltage, wherein the first voltage or a divided voltage thereof is a first input voltage, And outputs the divided voltage of the second voltage to the second voltage.
An operational amplifying circuit that is an input voltage of
One or more first fuse elements for changing the value of the voltage, and one or more first fuse elements connected to a circuit for generating the divided voltage of the second voltage, for changing the value of the second voltage. A reference voltage generating circuit comprising: one or a plurality of second fuse elements. 7. The reference voltage generating circuit according to claim 6, wherein the first fuse element is one or more of the plurality of resistance elements depending on a cut state / non-cut state of the first fuse element. A reference voltage generation circuit characterized by changing a resistance value. 8. The reference voltage generating circuit according to claim 6, wherein the first fuse element changes the use number of the bipolar transistor or the diode in accordance with a cut state / non-cut state. Reference voltage generation circuit. 9. The reference voltage generation circuit according to claim 6, wherein the second input voltage is a resistance divided voltage obtained by dividing the second voltage by a resistor. 10. The reference voltage generating circuit according to claim 6, wherein a cut point of the first fuse element is selected so as to minimize the temperature dependency of the first voltage, and the second variable means is provided. Wherein a cutting point is selected so as to minimize a difference between the second voltage and a target value. 11. One or more first diodes connected in series or parallel to each other, one or more second diodes connected in series or parallel to each other, and the first diode A first resistance element connected in series at a first connection point, a second resistance element connected in series to the second diode, and a second resistance element connected to each other at a second connection point; An operational amplifier circuit to which a first voltage appearing at the first connection point and a second voltage appearing at the second connection point are input, and which outputs a third voltage; A voltage measuring means for measuring a voltage and a third voltage; and a variable means for changing the third voltage, wherein the voltage is measured in accordance with the three voltage values measured using the voltage measuring means. Changing the third voltage by the variable means Reference voltage generating circuit according to claim. 12. The reference voltage generating circuit according to claim 11, wherein the voltage measuring means includes a first probing pad connected to the first connection point and a second probing pad connected to the second connection point, respectively. And a third probing pad connected to an output terminal of the first operational amplifier circuit. 13. One or a plurality of first diodes connected in series or parallel to each other; one or a plurality of second diodes connected in series or parallel to each other; and the first diode A first resistance element connected in series at a first connection point, a second resistance element connected in series to the second diode, and a second resistance element connected to each other at a second connection point; A first operational amplifier circuit to which a first voltage appearing at the first connection point and a second voltage appearing at the second connection point are input, and which output a third voltage; A second operational amplifier circuit that uses the divided voltage as a first input voltage, outputs a fourth voltage, and uses the fourth voltage or the divided voltage as a second input voltage, For measuring the second voltage, the third voltage and the fourth voltage A voltage measuring unit; and a variable unit for changing the third voltage and the fourth voltage, wherein the variable unit changes the third voltage according to the four voltage values measured by using the voltage measuring unit. A reference voltage generating circuit, wherein the third voltage and the fourth voltage are changed. 14. The reference voltage generating circuit according to claim 13, wherein a first probing pad and a second probing pad connected to the first connection point and the second connection point, respectively, A third probing pad connected to an output terminal of the first operational amplifier circuit;
And a fifth probing pad connected to an input terminal of a second input voltage of the second operational amplifier circuit, and a fourth probing pad connected to an output terminal of the operational amplifier circuit. Reference voltage generating circuit. 15. A first resistance ratio x1 and a second resistance ratio x2.
And a bandgap reference circuit having a first operational amplifier circuit for outputting a voltage dependent on the first saturation current ratio n, and the first resistance ratio x1 as dr1 (i) (1 = <i = <I)
Means for changing the second resistance ratio x2 by dr
2 (j) (1 = <j = <J), and / or variable means for changing the first saturation current ratio n by dr4 (k) (1 = <k = <K). A method for adjusting a reference voltage generating circuit, wherein when x1 fluctuates by dx1, x2 fluctuates by dx2, and n fluctuates by dn, A, B, and C are 0
Or 1 as a constant in which at least one of A, B, and C is 1, x1 ln [x2 n] (dx1 + Adr1 (i)) + x1 (d
x2 + Bdr2 (j) + dn + Cdr4 (k)) so that dr1 (i), dr2 (j) and / or d
A method for adjusting a reference voltage generating circuit, comprising the step of determining r4 (k) and changing x1 by dr1 (i), x2 by dr2 (j) and / or n by dr4 (k). 16. A first resistance ratio x1 and a second resistance ratio x2.
A bandgap reference circuit having a first operational amplifier circuit for outputting a first voltage dependent on a first saturation current ratio n, and a first resistance ratio x1 as dr1 (i) (1 = <i = <I) to change the second resistance ratio x2 by dr2 (j) (1 =
<j = <J), and / or a variable means for changing the first saturation current ratio n by dr4 (k) (1 = <k = <K); The divided voltage as the first input,
A second output of a second voltage dependent on a third resistance ratio x3;
And a variable means for changing the third resistance ratio x3 by dr3 (l) (1 = <l = <L), wherein x1 is dx1 A, B, and C are 0 when x2 fluctuates by dx2 and n fluctuates by dn.
Or 1 as a constant in which at least one of A, B, and C is 1, x1 ln [x2 n] (dx1 + Adr1 (i)) + x1 (d
x2 + Bdr2 (j) + dn + Cdr4 (k)) dr1 (i), dr2 (j) and / or dr4 (k) are determined so as to minimize x1, and x1 is changed by dr1 (i). (i), x2 is changed by dr2 (i), and / or n is changed by dr4 (k), the amount of change in the first voltage and x1, x2, n and the first operational amplifier circuit. The first voltage (V) when the input offset voltage is zero
0), the input offset voltage of the second operational amplifier circuit is dVin2, and the x3 is dx3
A step of determining dr3 (l) that minimizes dV-V0 (dr3 (l) + dx3) / x3 + dVin2 and changing x3 by dr3 (l). How to adjust the circuit.