JP3315060B2 - Reference voltage generation circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reference voltage generating circuit,
In particular, the present invention relates to a reference voltage generation circuit that is formed on a semiconductor integrated circuit and generates a temperature-compensated reference voltage using a bandgap voltage.

[0002]

2. Description of the Related Art A reference voltage generator utilizing a bandgap voltage is used as a reference voltage source of a semiconductor integrated circuit. FIG. 3 shows an example of such a conventional reference voltage generating circuit. The emitter area ratio of the transistor Q ₁₁ and the transistor Q ₁₂ is N: set to 1, each of the collector currents I
_C1 and I _C2 are transistors Q ₄₁ and Q ₄₂ , resistors R ₄₄ and R ₄₅
And the current values are equal. The emitter of the transistor Q ₁₁ is grounded through a resistor R _13, the resistor R _14, the emitter of the transistor Q ₁₂ is grounded through a resistor R _14. Further, the common base of the transistors Q ₁₁ and Q ₁₂ are connected to the output terminal O _REF of the reference voltage, the transistor Q ₄₃ in the output terminal O _REF to a buffer amplifier
The emitter is connected, and is configured to supply current to the base of the transistor Q _11, Q _12.

In the circuit shown in FIG.
The collector current I _C2 of the collector current I _C1 and the transistor Q ₁₂ of the _11, unit charge amount q, absolute temperature T, when the Boltzmann constant _{k, I C1 = I C2 =} (k · T / q · R 13 ) · In (N) (1) If I _C1 is determined, R ₁₃ can be obtained. The reference voltage V _REF, when the base-emitter voltage of the transistor Q ₁₂ and V _BE12, can be expressed by _{V REF = 2 · I C1 ·} R 14 + V BE12 ··· (2). As described above, since the collector current I _C1 is a constant determined by the resistor R ₁₃ and V _BE12 is also a constant, the reference voltage V _REF is determined by the value of the resistor R ₁₄ .

The temperature characteristic of the reference voltage (∂ / ∂T) V _REF is
Since the collector current I _C1 and the base-emitter voltage V _BE12 fluctuate due to temperature changes, (∂ / ∂T) V _REF = 2 ・ R ₁₄・ (∂ / ∂T) I _C1 + (∂ / ∂T) V _BE12 (3) Here, (∂ / ∂T) I _C1 is an equation obtained by differentiating the above equation (1) with the absolute temperature T. When this is substituted into the above equation (3), (∂ / ∂T) V _REF = 2 · (R ₁₄ / R ₁₃ ) · (k / q) · In (N) + (∂ / ∂T) V _BE12 (4) In the circuit shown in FIG. 3, even if the resistors R ₁₃ and R ₁₄ have temperature characteristics, if a resistor having the same temperature coefficient is used, (R ₁₄ / R ₁₃ ) in the above equation (4) is used. In addition, the temperature characteristic of the resistor can be canceled. It is known that the temperature characteristic (∂ / ∂T) V _BE12 of the base-emitter voltage in the second term on the right side of the above equation (4) has a negative temperature coefficient. And the temperature characteristic of the reference voltage V _REF can be set to zero. That the resistance of the resistor R _14, R ₁₄ = - setting the relationship of _{{R 13 · q / 2 ·} k · In (N)} · {(∂ / ∂T) V BE12} ··· (5) Thus, the temperature characteristic of the reference voltage can be set to zero. For example, temperature characteristics (∂ / ∂T) V
When the _BE12 and -2.5mV / k °, 2 (R 14 / R 13) · In (N) = 29.4
The reference voltage V is independent of temperature
_REF = 1.205V (in the case of silicon) is obtained.

[0005]

However, in the conventional reference voltage generating circuit, as described above, when a temperature-compensated (temperature characteristic (∂ / ∂T) V _REF = 0) reference voltage is to be obtained,
The output reference voltage V _REF is fixed at about 1.2V. Although be varied resistance R ₁₄ the value of V _REF can be changed, the temperature characteristic is changed as shown in FIG. 4, obtained can not be realized the temperature characteristic 0, therefore 1.2V or more reference voltages In such a case, there is a problem that a voltage conversion circuit must be provided at a subsequent stage of the circuit.

The present invention has been made in order to solve such a problem. For example, a reference voltage having a desired value of 1.2 V or more is generated at a temperature characteristic of 0. (1.2V or more).

[0007]

Reference voltage generating circuit according to the present invention According to an aspect of the base-emitter new resistor between R ₃₁ of the emitter area ratio of the conventional circuit transistor Q ₁₂ is 1
Connect is obtained by the adjusting the resistance value of the resistor R ₃₁ and the resistor R _14.

[0008] With such a circuit configuration, the reference voltage V _REF obtained is the base-emitter voltage V _BE12 of the transistor Q ₁₂ an emitter area ratio of 1, the resistance R ₁₄ between the emitter-GND It is the sum of the generated voltage _VR14 . Voltage V _R14 occurring in the resistor R ₁₄ is determined by the current flowing through the resistor R ₁₄ and its resistance. Current flowing through the resistor R ₁₄ is provided with a collector current I _C1, I _C2 of the two transistors Q _11, Q _12, the sum of the current flowing through the resistor R ₃₁ connected between the base and emitter of the transistor Q _12. Since the base-emitter voltage V _BE12 is a constant value,
It is possible to change the sum of the current flowing through the resistor R ₁₄ by a resistor R ₃₁ connected between the emitter. Accordingly, the resistance value of the resistor R ₁₄ between the emitter-GND of the transistor Q _12, by the resistance of the resistor R ₃₁ between the base and emitter, can determine the reference voltage V _REF to be output.

On the other hand, the temperature characteristic of the reference voltage (∂ / ∂T) V _REF
Includes a temperature characteristic of the base-emitter voltage of the transistor Q ₁₂ emitter area is _{1 (∂ / ∂T) V BE12} , temperature characteristics of the voltage generated in the resistor R ₁₄ between the emitter-GND (∂ /
∂T) V Sum of _R14 . Base-emitter voltage V _BE12
Has a constant negative temperature characteristic as described above. The temperature characteristics of the voltage generated in the resistor R ₁₄ between the emitter · GND becomes multiplied by resistance to the temperature characteristic of the current flowing through the resistor R _14. Collector current I flowing through the resistor R _14
C1 and I _C2 have a positive temperature characteristic and an emitter area of 1
Current flowing through the resistor R ₃₁ connected between the base and emitter of the transistor Q ₁₂ is a current also having a negative temperature characteristic because the base-emitter voltage has a negative temperature characteristic. Therefore, the collector currents I _C1, I _C2, the temperature characteristic of the current flowing through the resistor R ₃₁ is changed to the opposite direction. Thus the resistors R _31, and controls the temperature characteristic of the current flowing through the resistor R ₁₄ connected between the emitter · GND, it is possible to set the temperature characteristic of the voltage generated in the resistor R _14. Temperature characteristics of the base-emitter voltage as described above (∂ / ∂T) V _BE12, since a negative constant value, so as to cancel this, the temperature characteristics of the voltage generated in the resistor R ₁₄ (∂ /
If ∂T) V _R14 is set to the same positive temperature characteristic, the temperature characteristic (∂ / ∂T) V _REF of the output reference voltage becomes zero.

[0010] The reference voltage generating circuit specifically the present invention is formed a connected emitter surface product respective emitters to the power supply in the transistors 41 and 42 of a pair of the <br/> axis, of one
The collector of transistor 41 is the base of both transistors 41 and 42.
A current mirror circuit connected to the over scan, emitter area ratio N: 1, a transistor of a pair of the base are connected to each other, the collector before Quito lunge <br/> Star 41 transistors 11 and connected to the collector of
Its collector is connected to the collector of the transistor 42.
A transistor 12, and an output terminal OREF connected to said transistor 11,1 2 based <br/> scan, a resistor 13 connected between the emitters of said transistors 12 of the transistor 11, The emitter of the transistor 12 and GN
A resistor 14 connected between by D, a collector connected to said power source, base of the transistor 42,12 collector
A transistor connected between a transistor 43 for supplying a current to the prior SL transistors 11, 12 based of
A voltage generated at the resistor 14 and the transistor
The reference voltage, which is the sum of the base-emitter voltage of the
In the reference voltage generating circuit that outputs to the output terminal OREF,
And one end is connected to the base of the transistors 11 and 12
Connected, the other end connected to the emitter of the transistor 12
The resistor 31 and the transistor 43
A current is supplied to the resistor 14 via 31 to obtain a high reference voltage.
Characterized in that that.

Further, an output terminal OREF, the respective emitter area ratio N: 1, a transistor of a pair of the base are connected to each other, a collector resistor 21
The transistor 11 connected to the output terminal OREF through
And a resistor whose collector has the same resistance value as the resistor 21.
Connected to the output terminal OREF via a resistor 22;
A transistor 12 having a collector connected to its base;
A resistor 13 connected between the emitter and the GND of the transistor 11, a base connected to the collector of the transistor 11, a collector connected to said output terminal OREF, a transistor having an emitter connected to the GND , a transistor 15 which also the transistor 12 and the emitter surface product, comprising a base emitter of the transistor 12
And the voltage generated at the resistor 22.
Reference voltage generation circuit for outputting a reference voltage to the output terminal OREF
In addition, one end has a base of the transistors 11 and 12.
And the other end connected to GND.
Connected between the base of transistor 15 and GND,
Having a resistor 31 and a resistor 32 having the same resistance value,
It is characterized by obtaining a high reference voltage .

Further, these circuits are characterized in that they are circuits formed on a semiconductor integrated circuit.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of a circuit configuration of a reference voltage generation circuit according to the present invention. In FIG. 1, 11 and 12 have respective emitter area ratios N:
One transistor Q ₁₁ , Q ₁₂ , OREF is a transistor Q
₁₁ is an output terminal connected to the common base of Q _12.
The resistance R ₁₃ of the emitter of the transistor Q ₁₁ is 13,
Via the resistor R ₁₄ of 14 are grounded, the emitter of the transistor Q ₁₂ is grounded through a resistor R ₁₄ of 14. Reference numeral ₃₁ denotes a pair of transistors Q ₄₁ , Q ₄₂ , 44, and 45 which are provided between the base and the emitter of the transistor Q ₁₂ and form a current mirror circuit with the same emitter area ratio. Are resistors R ₄₄ and R ₄₅ forming a current mirror circuit, and 43 is a transistor Q ₄₃ forming a buffer amplifier. The resistance R ₁₃
Values are determined by the collector current I _C1 of the prior art as well as the transistor Q _11.

Reference voltage V obtained by the circuit shown in FIG.
_REF is, between the base and emitter of the transistor Q ₁₂ voltage V
And _BE12, as it determines the sum of the voltage V _R14 occurring in the resistor _{R 14, V REF = V BE12} + V R14 = V BE12 + {(2 · I C1) + (V BE12 / R 31)} · R 14 (6). From these equations, the resistance R ₁₄ and the resistance R ₃₁
R ₃₁ = (R ₁₄ · V _BE12 ) / (V _REF -V _{BE 12} -2 · R ₁₄ · I _C1 ) (7)

The temperature characteristic of the obtained reference voltage V _REF (∂ /
(∂T) V _REF is (∂ / ∂T) V _REF = (∂ / ∂T) V _BE12 + ｛2 ・ (∂ / ∂T) I _C1 + (1 / R ₃₁ ) ・ (∂ / ∂T) V _BE12 ｝ · R ₁₄ ... (8) From this equation (8), the resistance R ₁₄ and the resistance
Relation R _{31 is, R 31 = {R 14 ·} (∂ / ∂T) V BE12} / {(∂ / ∂T) V REF - (∂ / ∂T) V BE12 -2 · R 14 · (∂ / {T) I _C1 } (9) The resistance R ₁₄ derived from the reference voltage V _{REF in the} above equation (6)
And the relationship between the resistor R _31, and a relationship between the temperature characteristics (∂ / ∂T) and a resistor R ₁₄ which is derived from V _REF resistor R ₃₁ of the reference voltage of the aforementioned formula (8), the resistor R ₁₄ and the resistor R ₃₁ is required. That is, from equation (8), (、 / ∂T) V _REF = 2 · R ₁₄ · (∂ / ∂T) I _C1 + (1 + R ₁₄ / R ₃₁ ) · (∂
/ ∂T) V _BE12・ ・ ・ (10) is obtained, where (∂ /
(∂T) V _REF = 0, (∂ / ∂T) I _C1 = α, (∂ / ∂T) V _BE12 =
When replaced by β, R ₁₄ = −β / {2α + (β / R ₃₁ )} (11) From Expressions (6) and (11), V _REF = V _BE12 + ｛(2 · I _C1 ) + (V _BE12 / R ₃₁ )｝ · −β / {2α + (β / R ₃₁ )} (12), and V _REF can be determined by a function of R ₃₁ and R ₁₃ .
The R ₁₄ can also be defined as a function of R ₃₁ and R _13.

In this circuit, if the output reference voltage V _REF is 1.2 V or less, the resistance R ₁₄ or the resistance R ₃₁ becomes a negative value. Therefore, the obtained reference voltage V _REF is an arbitrary value of 1.2 V or more. Value.

As an application example, the temperature characteristic of the reference voltage arbitrarily set by this circuit can be changed to some extent. As an example, the temperature characteristics of the output reference voltage (∂ /
The ∂T) V _REF, a temperature characteristic of the base-emitter voltage of the transistor Q ₁₂ (∂ / ∂T) Consider the case of setting equal to V _BE12. Output reference voltage temperature characteristics (∂ / ∂T) V _REF
From obtained from the resistor R ₁₄ and relationship of the resistance R ₃₁ (9), the resistance R _{31 is, R 31 = - {(∂} / ∂T) V BE12} / {2 · (∂ / ∂T) I C1} (13) Note that (∂ / ∂T) V _{BE12 in} equation (13) is a constant negative value as described above, and (∂ / ∂T) I _C1 is a constant positive value.

FIG. 2 is a circuit diagram showing another embodiment of the present invention. 2, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and ₂₁ , ₂₂ , and 32 denote resistors R ₂₁ and R ₂₁ , respectively.
R ₂₂ , R ₃₂ , and 15 are transistors Q _{15. In} order to make the collector currents of the transistors Q ₁₁ and Q ₁₂ the same, the resistances of the resistors R ₂₁ and R ₂₂ and the resistors R ₃₁ and R ₃₂ resistance value is set equal to the emitter area of the transistor Q ₁₅ is set to be the same as the emitter area of the transistor Q _12.

[0019] The collector current I _C1 of the transistor Q ₁₁ is,
When the base-emitter voltage of the transistor Q ₁₅ and V _BE15, expressed by _{I C1 = (V REF -V BE15} ) / R 21 -V BE15 / R 32 ··· (14). In addition, the collector current I _C2 of the transistor Q ₁₂
Is, the base-emitter voltage of the transistor Q ₁₂ V
_{Assuming BE12} , I _C2 = (V _REF -V _BE12 ) / R ₂₂ -V _BE12 / R ₃₁ (15) Since the transistor Q ₁₂ and the transistor Q ₁₅ has the same characteristics, V _BE12 and V _BE15 are equal, also the resistance R ₂₁ and the resistor R _22, since the resistor R ₃₁ resistor R ₃₂ are equal, the above equation (14) Since the right sides of (15) and (15) are equal, I _C1 and I _C2 are the same. The value of the resistor R _13, the collector current I of the prior art as well as the transistor Q ₁₁
Determined by _C1 .

Reference voltage V obtained in this circuit configuration
_REFIs the transistor Q₁₂ Base-emitter voltage V
_BE12 And the resistance R_{twenty two} Voltage V generated at_R22 Determined by the sum of
Then V_REF= V_BE12+ V_R22 = V_BE12+ (I_C1+ V_BE12/ R₃₁) ・ R_{twenty two}(16), and from these equations, the resistance R_{twenty two} And resistance R₃₁ Relationship with
The clerk, R₃₁= (R_{twenty two}・ V_BE12) / (V_REF-V_BE12-I_C1・ R₁₂) (17) Also, the obtained reference voltage V_REF Temperature characteristics (∂ /
∂T) V_REF Is (∂ / ∂T) V_REF= (∂ / ∂T) V_BE12+ ｛(∂ / ∂T) Ic₁+ (1 / R₃₁) ・ (∂ / ∂T) V_BE12｝ ・ R _{twenty two} .. (18). From this equation (18), the resistance R_{twenty two} And resistance
R₃₁ The relationship is R₃₁= ｛R_{twenty two}・ (∂ / ∂T) V_BE12｝ / ｛(∂ / ∂T) V_REF-(∂ / ∂T) V_BE12-R_{twenty two}・ (∂ / ∂T) Ic₁｝ ... (19)

[0021] The temperature characteristic of the resistor R ₂₂ derived from the reference voltage V _REF obtained by the above equation (16) and the relationship of the resistor R _31, a reference voltage obtained by the aforementioned formula (18) (∂ / ∂ T) V
The relationship between the resistance R ₂₂ guided resistor R ₃₁ from _REF, 1
The resistance R ₃₁ and the resistor R ₂₂ in the same manner as the circuit shown in demanded. In this circuit, the output reference voltage V _REF is
If it is below 1.2V, the resistance R ₂₂ or a resistance R ₃₁ is a negative value, the reference voltage obtained is the arbitrary value of more than 1.2V.

Also in the circuit of FIG. 2, the temperature characteristics of the arbitrarily set reference voltage can be changed to some extent. As an example, the temperature characteristics of the output reference voltage
(∂ / ∂T) Temperature characteristics of the base-emitter voltage of the V _REF transistor Q ₁₂ (∂ / ∂T) Consider the case of setting equal to V _BE12. Temperature characteristics of output reference voltage (∂ / ∂T) V
Relationship between the resistance R ₂₂ obtained from _REF resistor R ₃₁ (1
From 9), the resistance R ₃₁ becomes R ₃₁ = − ₃₁ (∂ / ∂T) V _BE12 ｝ / ｛(∂ / ∂T) I _C1 ｝ (20)

[0023]

Reference voltage generating circuit of the present invention as described above, according to the present invention, by the emitter area is a resistor between the base and emitter of the transistor Q ₁₂ is 1, the temperature characteristic of the reference voltage output is An arbitrary voltage of 1.2 V or more can be obtained at 0, and connection of a voltage conversion circuit in a semiconductor integrated circuit requiring a high reference voltage can be eliminated, and the entire circuit can be simplified. Since a desired reference voltage can be set and the temperature characteristics of the reference voltage can be selected within a certain range, the temperature characteristics of other circuits connected in the semiconductor integrated circuit can be offset without using a temperature characteristic conversion circuit. Can,
Even in such a case, there is an effect that the size of the entire circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of the configuration of a conventional reference voltage generation circuit of this type.

4 is a diagram showing a problem of the conventional circuit shown in FIG.

[Explanation of symbols]

11, 12, 15, 41, 42, 43 Transistors 13, 14, 21, 22, 31, 32, 44, 45 Resistance I _C1 , I _c2 Collector current having the same current value OREF Output terminal

Claims (3)

(57) [Claims] 1. Each emitter is connected to a power supply .
Formed by transistors 41 and 42 of a pair of like-emitter surface product, the collector of one transistor 41 both Trang
Current mirror circuit connected to the bases of the transistors 41 and 42
If, emitter area ratio N: 1, a transistor of a pair of the base is contact <br/> connection with each other, its collector connected to the collector of <br/> before Quito transistor 41 and transistor <br/> motor 11, and a transistor 12 whose collector is connected to <br/> Kuta of the transistor 42, base over scan the connected output terminals of the transistors 11 and 12
And OREF, a resistor 13 connected between the emitters of said transistors 12 of the transistor 11, a resistor 14 connected between the emitter and the GND of the transistor 12 is connected collector to said power source , a voltage to a transistor whose base is connected between the collector of the transistor 42,12, a front Symbol transistors 11, 12 transistor 43 supplies current to the base of comprises, generated in the resistor 14 , The transistor 12
Output a reference voltage that is the sum of the source-emitter voltage
In the reference voltage generating circuit for outputting to the terminal OREF , one end is further connected to the bases of the transistors 11 and 12
And the other end is connected to the emitter of the transistor 12.
The resistor 14 via the resistor 31 from the transistor 43.
A reference voltage generating circuit for supplying a current to the circuit and obtaining a high reference voltage . (2)Output terminal OREF, Each emitter area ratio is N: 1AndIts base
ButEach otherConnectedoneA pair of transistors,That
A collector is connected to the output terminal OREF via a resistor 21.
Transistor 11 and its collector are connected to the resistor 21
Connected to the output terminal OREF via a resistor 22 with the same value
And the collector is connected to its base
Transistor 12,  Connected between the emitter of the transistor 11 and GND
Resistance 13When,  The base is connected to the collector of the transistor 11,
Lector is saidOutput terminal OREFAnd the emitter is connected to GND
A transistor connected to the
12 and emitter surfaceMultiplySame transistor 15When,With The base-emitter voltage of the transistor 12,
A reference voltage that is the sum of the voltage generated at the resistor 22 and the output
In the reference voltage generation circuit that outputs to the terminal OREF, further, One end is connected to the bases of the transistors 11, 12,
A resistor 31 whose end is connected to GND, Connected between the base of the transistor 15 and GND;
A resistor 32 having the same resistance value as the resistor 31; To obtain a high reference voltage Reference voltage source
Raw circuit. 3. The reference voltage generation circuit according to claim 1, wherein the reference voltage generation circuit is a circuit formed on a semiconductor integrated circuit.