JPH07210265A - Reference voltage generating circuit - Google Patents

Abstract

PURPOSE:To provide a reference voltage generating circuit which does not effect a temperature compensating circuit despite the improvement of a power supply function. CONSTITUTION:The base current of an output transistor TR Q1 is controlled based on the current supplied from a constant current source Ia, and the output voltage Vout is outputted between the emitter of the TR Q1 and the voltage dividing resistances R1 and R2. The temperature compensating resistances R3 and R4 are connected to the emitters of the variance detecting TR Q5 and O6 respectively. Then the detecting voltage VBG is inputted to the bases of both TR Q5 and Q6, and the currents balanced with each other are supplied to the TR Q5 and Q6 from the current control TR Q2 and Q3. A control TR Q7 detects the variance of the balanced currents flowing to the TR Q5 and Q6 based on the variance of the voltage VBG. Then a current distribution control circuit 5 controls the base current of the TR Q1 against the detected degree of current variance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference voltage generating circuit, and more particularly to a reference voltage generating circuit provided in a semiconductor integrated circuit device.

In recent years, the scale and speed of semiconductor integrated circuit devices have been increasing. Along with this, the reference voltage generating circuit that supplies operating power to each internal circuit is required to increase its power supply capability. When increasing the power supply capability of the reference voltage generating circuit, it is necessary to ensure that the output voltage output from the generating circuit is stable.

[0003]

2. Description of the Related Art Conventionally, a bandgap reference type circuit is known as a reference voltage generating circuit. This type of reference voltage generating circuit is excellent in temperature compensation and outputs a constant voltage even if the temperature changes. This reference voltage generating circuit is shown in FIG.
Shown in.

In FIG. 3, an NPN output transistor Q
1, the collector is connected to the high voltage power supply Vcc, and the emitter is connected to the low voltage power supply (ground) via the voltage dividing resistors R1 and R2. The base of the output transistor Q1 is connected to the constant current source Ia. The output voltage Vout is output from the connection point A between the emitter of the output transistor Q1 and the resistor R1. The output transistor Q1, the constant current source Ia, and the voltage dividing resistors R1 and R2 form an output circuit section.

To the connection point A, the emitters of current control PNP transistors Q2 and Q3 are connected. The bases of the transistors Q2 and Q3 are both PNP transistor Q4.
Of the transistor Q4, and the collector of the transistor Q4 is connected to the ground. Also, transistor Q4
Is connected to the collector of the transistor Q2. The three transistors Q2 to Q4 form a current mirror circuit section.

The collector of the transistor Q2 is connected to the collector of a fluctuation detecting NPN transistor Q5, and the emitter of the transistor Q5 is connected to the ground via a temperature compensating resistor R4. Also, the transistor Q3
Is connected to the collector of a fluctuation detecting NPN transistor Q6, and the emitter of the transistor Q6 is connected to a connection point B between the emitter of the transistor Q5 and the resistor R4 via a temperature compensating resistor R3. The area size of the emitter size of the transistor Q6 is set to J times (J> 1) the size of the emitter size of the transistor Q5. Also, a transistor Q6 that is J times larger
The value of the resistor R3 connected to
The emitter currents of 6 are set to be equal.
The bases of both transistors Q5 and Q6 are the resistors R1 and R
It is connected to a connection point C between the two.

The collector of the transistor Q6 is connected to the base of a PNP transistor Q7 for control.
The emitter of the transistor Q7 is connected to the constant current source Ia, and the collector of the transistor Q7 is connected to the ground via the diode D1.

When the output voltage Vout changes, for example, decreases, the voltage VBG at the connection point C also decreases correspondingly. Voltage V
When BG decreases, the collector current of the transistor Q6 decreases and the base current of the transistor Q7 decreases. As a result, the emitter current of the transistor Q7 decreases, and the current flowing from the constant current source Ia to the base of the transistor Q1 increases by the decrease amount. Then, the emitter current of the transistor Q1 is increased to raise the output voltage Vout and the voltage VBG to restore the original constant voltage.

Conversely, when the output voltage Vout rises, the voltage VBG at the connection point C also rises relative to it. When the voltage VBG rises, the collector current of the transistor Q6 increases,
The base current of the transistor Q7 increases. As a result, the emitter current of the transistor Q7 increases and the current flowing from the constant current source Ia to the base of the transistor Q1 decreases by the increase. Then, the emitter current of the transistor Q1 is reduced to lower the output voltage Vout and the voltage VBG and restore the original constant voltage.

In the reference voltage generating circuit, the collector currents Ic5 and Ic6 of the transistors Q5 and Q6 have the same value (I
c5 = Ic6). At this time, the resistance R3
The voltage VR3 across both ends of is expressed by VR3 = (kT / q) lnJ. k is Boltzmann's constant, T is absolute temperature,
q is the amount of electric charge, J is the area ratio of the emitter, and the voltage VBG at the connection point C is VBG = VR4 + VBE5 = 2 ( R4 / R3) · (kT / q) lnJ + VBE5.

As is clear from this equation, VBE5 has a negative temperature coefficient and VR4 has a positive temperature coefficient. Therefore,
The values of R3, R4, and J are appropriately selected to set the temperature coefficient of the voltage VBG to zero so that the output voltage Vout does not fluctuate depending on the temperature.

[0012]

In the reference voltage generating circuit, the power (current) supply depends on the constant current source Ia and the current amplification factor hFE of the transistor Q1. Therefore,
To increase the power supply capacity, the easiest method is to increase the current value output by the constant current source Ia.

However, increasing the current value output from the constant current source Ia means that the current to be controlled by the transistor Q7 increases. When the current to be controlled by the transistor Q7 increases, the base current of the transistor Q7 flowing in the collector of the transistor Q6 also increases. As a result, transistors Q5, Q for temperature compensation
This affects the equilibrium of the current flowing in 6 (Ic5 = Ic6) and causes an error with respect to the voltage VBG at the connection point C.

The present invention has been made in order to solve the above problems, and an object thereof is to improve the power supply capacity, and to increase the capacity not to affect the temperature compensation circuit. It is to provide a voltage generating circuit.

[0015]

FIG. 1 is a diagram for explaining the principle of the present invention. The output circuit unit 1 is composed of a constant current source Ia, an output transistor Q1, and voltage dividing resistors R1 and R2.
The collector of the output transistor Q1 has a high power supply voltage Vc.
c, the emitter is connected to the ground via the voltage dividing resistors R1 and R2, and the output voltage Vou is output from the emitter.
t is output. A constant current source Ia is connected to the base of the output transistor Q1.

The fluctuation detecting circuit section 2 is composed of fluctuation detecting transistors Q5 and Q6 and temperature compensating resistors R3 and R4. The fluctuation detecting transistors Q5 and Q6 are composed of transistors having different emitter sizes. The bases of the fluctuation detecting transistors Q5 and Q6 are connected between the voltage dividing resistors R1 and R2, and the detection voltage (VBG) opposite to the output voltage Vout is input. The emitter of the variation detecting transistor Q6 having the larger emitter size is connected to the ground via the temperature compensating resistors R3 and R4. The emitter of the variation detecting transistor Q5 having the smaller emitter size is connected to the ground via the temperature compensating resistor R4.

The current mirror circuit section 3 is composed of current controlling transistors Q2 and Q3 and a transistor Q4. The transistor Q4 has its emitter connected to the bases of the current control transistors Q2 and Q3, and its collector connected to the ground. The base of the transistor Q4 is connected to the collector of the fluctuation detecting transistor Q5 having the smaller emitter size. Both emitters of the current control transistors Q2 and Q3 are connected to the emitter of the output transistor Q1. The collector of the current control transistor Q2 is connected to the collector of the fluctuation detection transistor Q5. The collector of the current control transistor Q3 is connected to the collector of the fluctuation detection transistor Q6.

The control circuit section 4 comprises a control transistor Q7, the base of which is connected to the collector of the fluctuation detection transistor Q6. The collector of the control transistor Q7 is connected to the ground, and the emitter is connected to the current distribution control circuit 5. The current distribution control circuit 5 has one end connected to the base of the output transistor Q1 and the other end connected to the emitter of the control transistor Q7. The current distribution control circuit 5 is a circuit that supplies a part of the current supplied from the constant current source Ia to the control transistor Q7 side to the control transistor Q7.

[0019]

Therefore, according to the present invention, when the value of the constant current source Ia is increased to increase the power supply capability of the output transistor Q1, the base current of the output transistor Q1 by the control transistor Q7 with respect to the fluctuation of the output voltage Vout. The control amount of becomes large.

That is, the fluctuation range of the current value flowing from the constant current source Ia to the control transistor Q7 side is large. At this time, only a part of the current supplied from the constant current source Ia to the control transistor Q7 side by the current distribution control circuit 5 flows to the control transistor Q7.

Therefore, the base current of the control transistor Q7 controls the emitter current of the transistor Q7 with a small value, and by this control, the base current of the output transistor Q1 with a large value can be controlled.

As a result, the control transistor Q7 can be operated with a small base current,
The balance of the collector currents of the fluctuation detecting transistors Q5 and Q6 for temperature compensation can be maintained in a stable state.

[0023]

An embodiment embodying the present invention will be described below with reference to FIG. Note that, for convenience of explanation, the same components as those in FIG. 3 are designated by the same reference numerals, and the description thereof will be partially omitted.

In FIG. 2, a multi-collector PNP transistor (hereinafter referred to as a multi-collector transistor)
The emitter of Q10 is connected to the constant current source Ia. The multi-collector transistor Q10 has three collectors, one is connected to the bases of the PNP transistors Q2 and Q3, one is connected to the ground, and the remaining one is connected to the anode of the diode D2. As for the area ratio of the size of the three collectors, when the collector connected to the transistors Q2 and Q3 is 1, the collector connected to the ground is m and the collector connected to the diode D2 is n.

The base of the multi-collector transistor Q10 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to the PNP transistor Q described above.
7 emitters. The base of the transistor Q7 is connected to the collector of the NPN transistor Q6, and the collector of the transistor Q7 is directly connected to the ground unlike the conventional example.

The diode D2 is a potential adjusting circuit for making the base potential of the transistor Q4 constituting the current mirror circuit equal to the base potential of the multi-collector transistor Q10. That is, the potential VE of the connection point E viewed from the connection point A and the potential VF of the connection point F viewed from the connection point A are as follows.

VE = Vout-VBE2-VBE4 VF = Vout + VBE1-VBE10-VD2-VBE7 VBE1 is the base-emitter voltage of the transistor Q1,
VBE2 is the base-emitter voltage of the transistor Q2,
VBE4 is the base-emitter voltage of transistor Q4,
VBE7 is the base-emitter voltage of transistor Q7,
VBE10 is the voltage between the base and emitter of the transistor Q10, VD2 is the voltage between the terminals of the diode D2, and in this embodiment, assuming that the voltage between the base and emitter of each transistor and the voltage of the diode are equal, VF = VE. That is, the collector currents IC5 and IC6 are balanced by VF = VE.

Next, the operation of the reference voltage generating circuit configured as described above will be described. When the output voltage Vout fluctuates and decreases, the voltage VBG at the connection point C also decreases correspondingly. When the voltage VBG drops, the collector current I of the transistor Q6
C6 becomes smaller and the base current IB7 of the transistor Q7 decreases. As a result, the emitter current IE7 of the transistor Q7
Is reduced, that is, the emitter current IE10 of the multi-collector transistor Q10 is reduced. Then, the current flowing from the constant current source Ia to the base of the transistor Q1 increases by the decrease amount. Therefore, the emitter current of the transistor Q1 is increased to raise the output voltage Vout and the voltage VBG and return to the original constant voltage.

On the contrary, when the output voltage Vout rises, the voltage VBG at the connection point C also rises relatively. When the voltage VBG rises, the collector current IC6 of the transistor Q6 increases and the base current IB7 of the transistor Q7 increases. As a result, the emitter current IE7 of the transistor Q7 increases, that is, the emitter current I7 of the multi-collector transistor Q10.
E10 increases. The constant current source Ia is increased by the increment.
To the base of the transistor Q1 decreases. Therefore, the emitter current of the transistor Q1 is reduced to lower the output voltage Vout and the voltage VBG and return to the original constant voltage.

Therefore, the reference voltage generating circuit can output the output voltage Vout having a constant value even if the high voltage power supply Vcc fluctuates for some reason. Also,
In this embodiment, in order to increase the power supply capacity, the constant current source I
Even if the value of a is increased, the balance of the collector currents Ic5 and Ic6 of the transistors Q5 and Q6 (Ic5 = Ic6) is maintained, temperature compensation is performed due to temperature fluctuation, and a constant output voltage Vout is output. You can

That is, the factors affecting the balance (Ic5 = Ic6) of the collector currents Ic5 and Ic6 of the transistors Q5 and Q6 are the base currents IB4 and IB7 of the transistors Q4 and Q7, respectively.

The emitter current of the transistor Q4 is IE4,
When the amplification factor is hFE, the base current IB4 of the transistor Q4 is: IB4 = IE4 / (1 + hFE) IE4 = IC10 + (IE2 + IE3) / hFE IC10 is the collector of the multi-collector transistor Q10 connected to the bases of the transistors Q2 and Q3. Collector current, IE2 is the emitter current of transistor Q2, IE4
Is the emitter current of the transistor Q3, and therefore IB4 = {IC10 + (IE2 + IE3) / hFE} / (1 + hF
E) On the other hand, assuming that the emitter current of the transistor Q7 is IE7 and the amplification factor is hFE, the base current IB7 of the transistor Q7.
IB7 = IE7 / (1 + hFE) IE7 = nIC10 + (1 + m + n) IC10 / hFE n, m is the area ratio of the multi-collector transistor Q10,
Therefore, IB7 = {nIC10 + (1 + m + n) IC10 / hFE} /
(1 + hFE) ... Then, assuming that the amplification factors hFE of the transistors Q2 to Q4, Q7, and Q10 are the same, and have a sufficiently large value, and n = 1, the formula is IB4≈IC10 / (1 + hFE) ... IB7≈ IC10 / (1 + hFE) ... Therefore, IB4 = IB7.

On the other hand, the collector current Ic5 of the transistor Q5 is Ic5 = IB4 + {hFE / (1 + hFE)} IE2 The collector current Ic6 of the transistor Q6 is Ic6 = IB7 + {hFE / (1 + hFE)} IE3 At this time, the transistors Q2 and Q3 are the same. Since there is no offset voltage between the two in shape, IE2 = IE3.

Therefore, this IE2 = IE3 and the above-mentioned IB4
= IB7, Ic5 = Ic6 holds. Thus, in this embodiment, the transistors Q2 to Q4, Q7 and Q10 are
Of the collector currents Ic5, Ic6 of the transistors Q5, Q6 by setting the area ratio n of the multi-colenta transistor Q10 to "1" while making the amplification factor hFE of the transistors Q5 and Qc6 the same.
Is maintained, temperature compensation is performed by temperature fluctuation, and a constant output voltage Vout can be output.

Moreover, in this embodiment, the multi-collector Q is used.
10 are provided, and collector currents IC10, mIC10, respectively from the collectors of the multi-collector transistor Q10 are provided.
nIC10 is distributed and output. Therefore, the constant current source Ia
To the multi-collector Q10, that is, the emitter current IE10 (≈ (1 + m + n) IC10) is larger than the base currents IB4 and IB7 of the transistors Q4 and Q7. In other words, even if the emitter current IE10 is large, the base currents IB4 and IB7 can be small. As a result, in order to increase the power supply capacity, the constant current source I
Even if a is increased, the values of the base currents IB4 and IB7 are small, so the influence on the temperature compensation, that is, the balance of the collector currents Ic5 and Ic6 of the transistors Q5 and Q6 (Ic5 = Ic6) is very small, and the stable output is obtained. The voltage Vout can be output.

The present invention is not limited to the above-mentioned embodiment, and for example, one transistor Q1 may be replaced with a plurality of transistors by Darlington connection. In this case, by configuring with a plurality of transistors, a configuration matching the power supply capability becomes possible.

Further, the transistor Q of the current mirror circuit
2, Q3 emitter currents IE2 and IE3 are balanced (IE2 = I
In order to keep E3), a small resistor may be connected to the emitters of the transistors Q2 and Q3 for adjustment.

The technical ideas other than the claims that can be understood from the above-described embodiments will be described below along with their effects. The reference voltage generating circuit according to claim 2, wherein the control transistor Q7 and the PNP multi-collector transistor Q1.
A diode for equalizing the collector potentials of the fluctuation detecting transistors (Q5, Q6) is provided between the diode and 0.
Collector current IC of fluctuation detecting transistors Q5 and Q6
5, balance of IC6 is secured.

[0039]

As described in detail above, according to the present invention, the power supply capability can be increased, and even if the capability is increased, the temperature compensating circuit is not affected.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a reference voltage generation circuit diagram for explaining an embodiment of the present invention.

FIG. 3 is a conventional reference voltage generation circuit diagram.

[Explanation of symbols]

 1 Output Circuit Section 2 Fluctuation Detection Circuit 3 Current Mirror Circuit Section 4 Control Circuit Section 5 Current Distribution Control Circuit Q1-Q7 Transistors Q10 Multi-collector Transistors R1, R2 Voltage Dividing Resistors R3, R4 Temperature Compensating Resistors Ia Constant Current Source

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisao Suzuki 2844-1 Kozoji-cho, Kasugai-shi, Aichi Prefecture

Claims (3)

[Claims] 1. A constant current source (Ia), wherein a voltage dividing resistor (R1, R2) is connected to an emitter of an output transistor (Q1).
The output circuit section (1) that outputs the output voltage (Vout) by controlling the base current of the output transistor (Q1) based on the current from the output transistor and the pair of fluctuation detection transistors (Q5, Q6) having different emitter sizes. ) Is connected to temperature compensating resistors (R3, R4) for detecting the potential difference between the emitters of both transistors (Q5, Q6), and the voltage dividing resistor (R5, Q6) is connected to the bases of both transistors (Q5, Q6). R1,
The fluctuation detection circuit section (2) that receives the detection voltage (VBG) from R2) and the pair of current control transistors (Q2, Q3) driven by the transistor (Q4) generate balanced currents. A current mirror circuit section (3) that flows through the fluctuation detection transistors (Q5, Q6) and a balanced current flowing through the fluctuation detection transistors (Q5, Q6) based on fluctuations in the detection voltage (VBG). A reference voltage generating circuit comprising a control circuit section (4) for detecting a variation in a control transistor (Q7) and controlling a base current of the output transistor (Q1), the control transistor of the control circuit section (4). A reference voltage generation circuit characterized in that a current distribution control circuit (5) is provided between (Q7) and the base of the output transistor (Q1). 2. The control transistor (Q7) of the control circuit section (4) is a PNP transistor, and the current distribution control circuit (5) is a PNP multi-collector transistor (Q10) having a plurality of collectors, and its emitter. Is connected to the base of the output transistor (Q1), the base and one collector are connected to the emitter of the control transistor (Q7), and at least the other one collector is provided in the current mirror circuit section (3) for current control. Transistor (Q
2. The reference voltage generating circuit according to claim 1, wherein the reference voltage generating circuit is connected to the bases of Q2 and Q3. 3. A PNP multi-collector transistor (Q
The number of collectors of 10) is three, one collector is connected to the emitter of the control transistor, one is connected to the base of the current control transistors (Q2, Q3), and the remaining one is connected to the ground. The reference voltage generating circuit according to claim 2.