JPH0954625A - Reference voltage generating circuit and semiconductor device using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce variation in reference voltage with a supplied current. SOLUTION: Resistances R1 and R2 are equal in resistance value to each other, the rate of the current density of the collector current of an NPN type transistor(TR) Q2 to the current value of the collector current of an NPN TR Q1 is >=1, and NPN type TRs Q3 and Q4 have the same characteristics. An output voltage VRR = (baseemitter voltage of Q3)+(R2/R3).(difference between the base-emitter voltage of Q2 and the base emitter voltage of Q1) is equalized to the energy gap of a semiconductor. The current IB4 which flows from the resistance R1 to the base of the NPN type TR Q4 and the current IB3 which flows from the resistance R2 to the base of the NPN type TR Q3 become equal to each other and the NPN type TR Q3 performs feedback control so as to make the currents I1 and I2 constant, so even if a current I0 varies, the output voltage VRR becomes constant.

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 for canceling a positive temperature coefficient of a base-emitter voltage difference and a negative temperature coefficient of a base-emitter voltage to reduce temperature drift, and a reference voltage generating circuit using the same. Related semiconductor device.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional reference voltage generating circuit. The terminal voltage ΔVBE of the resistor R3 is the difference between the base-emitter voltage of the NPN transistor Q2 and the base-emitter voltage of the NPN transistor Q1. N
PN transistor Q1 collector current IC1 and NPN
ΔVBE = (kT / q) when the collector current IC2 of the n-type transistor Q2 is equal to each other and the collector current density of the NPN-type transistor Q2 is N times (N> 1) the collector current density of the NPN-type transistor Q1. lnN (1) and the temperature coefficient becomes positive. Here, q is the charge of the electron, T is the absolute temperature, k is the Boltzmann constant, and ln is the natural logarithm. On the other hand, the temperature coefficient of the base-emitter voltage of the NPN transistor is negative. The base-emitter voltage of the NPN transistor Q13 is VBE (Q13)
Then, the output voltage VRR becomes: VRR = VBE (Q13) + (R2 / R3) ΔVBE (2), and there is a condition that theoretically does not depend on temperature (temperature drift becomes 0). , This condition is output voltage VR
R is equal to the band gap voltage of the semiconductor forming the transistor, which is 1.2 V in the case of silicon.

NPN type transistors Q1, Q2 and Q1
The current I0 from the constant current source 10 is distributed and supplied to 3. However, due to the temperature fluctuation of the semiconductor substrate, the current I
When 0 changes and the base current IB13 of the NPN transistor Q13 changes, a difference occurs between the collector current IC1 and the collector current IC2, the above equation (1) is not satisfied, and the output voltage VRR changes.

In order to solve this problem, a reference voltage generating circuit as shown in FIG. 6 has been proposed (Japanese Patent Laid-Open No. 3-8).
004 publication). In this circuit, the voltage across terminals of the resistor R15, VBE (Q2) + (R12 / R3) ΔVBE, is made equal to the bandgap voltage, so that the temperature of the output wiring VRR multiplied by {1+ (R14 / R15)} The drift becomes zero. Here, VBE (Q2) is NP
This is the base-emitter voltage of the N-type transistor Q2. In the figure, 11 and 12 are current mirror circuits,
Q13, Q15 and Q16 are NPN type transistors, and D is a diode.

[0005]

However, even in the circuit of FIG. 6, when the current I0 supplied to the reference voltage generating circuit changes due to temperature fluctuations of the semiconductor substrate, the base current I0 is changed.
B13 changes, and due to the asymmetry of the connection between the collector side of the NPN type transistor Q1 and the collector side of the NPN type transistor Q2, the collector current I1C and the collector current I
2C and a difference occurs, and the output voltage VRR changes as in the case of FIG. Further, since the current mirror circuits 11 and 12 are used, the number of transistor stages increases, and the resistance value of the resistor R14 cannot be set to 0, and the output voltage VRR becomes higher than the band gap voltage. The power supply voltage VCC is lowered in order to reduce the power consumption of the semiconductor integrated circuit, and accordingly, a lower output voltage VRR is required.

In view of the above problems, it is an object of the present invention to provide a reference voltage generation circuit capable of reducing the change in the reference voltage with respect to the change in the supply current, and a semiconductor device using the reference voltage generation circuit.

[0007]

In the reference voltage generating circuit of the first invention, for example, as shown in FIG. 1, the collector of the first NPN transistor Q1 and the second NPN transistor are connected.
The collector of the transistor Q2 has a first resistor R1
And an emitter of the first NPN type transistor Q1 and an emitter of the second NPN type transistor Q2 are directly connected to each other and a third NPN type transistor via a third resistor R3. It is connected to the collector of Q3 and the emitter and base of the third NPN transistor Q3 are respectively connected to the second wiring V.
SS and the collector of the second NPN transistor Q2, and the emitter and base of the fourth NPN transistor Q4 are the second wiring VSS and the first NPN, respectively.
Type transistor Q1 is connected to the collector of the fourth NP
The collector of the N-type transistor Q4 has fourth resistors R4 and R4.
5 is connected to the first wiring VRR via
The base of the second transistor Q1 and the base of the second NPN transistor Q2 are set to substantially the same potential, and a current supply means for supplying a substantially constant current is connected to the first wiring,
The resistance values of the first resistor R1 and the second resistor R2 are substantially equal to each other, and the ratio of the collector current current density of the second NPN transistor Q2 to the collector current current density of the first NPN transistor Q1 is 1 or less. Large, the third NPN
Type transistor Q3 and the fourth NPN type transistor Q4
Characteristics are substantially equal to each other and substantially equal to the energy gap of the semiconductor forming the first, second and third NPN transistors Q1, Q2 and Q3 between the first wiring VRR and the second wiring VSS. The same voltage is output as the reference voltage.

In the first aspect of the invention, even if the currents I1 and I2 change due to the change of the current I0 supplied by the current supply means, the current IB4 flowing from the first resistor R1 to the base of the fourth NPN transistor Q4 and The current IB flowing from the second resistor R2 to the base of the third NPN type transistor Q3
3 becomes substantially equal to each other, the collector current I1C of the first NPN transistor Q1 and the collector current I2C of the second NPN transistor Q2 become substantially equal to each other, and the output voltage between the first wiring VRR and the second wiring VSS. Becomes almost constant. Also, the third NPN transistor Q3
By this, the currents I1 and I2 are feedback-controlled so as to be substantially constant, so that the output voltage becomes more constant.

In the first aspect of the first invention, for example, as shown in FIG. 1, the collector of the fourth NPN transistor Q4 is connected to one end of the fourth resistor R5, and the fourth resistor R5 is connected.
The other end of which is connected to the bases of the first and second NPN transistors Q1 and Q2 on the one hand, and the fifth on the other hand.
It is connected to the second wiring VRR through the resistor R4.

In this first aspect, the first and second NPN
Since the bases of the type transistors Q1 and Q2 are connected to the other end of the fourth resistor R5, the structure is simplified. In the second aspect of the first aspect of the invention, for example, as shown in FIG. 3, the current supply means includes a fifth NPN whose collector and emitter are connected to the power supply line VCC and the first wiring VRR, respectively.
Type transistor Q5, the power supply line VCC and the fifth N
A constant current source 10A connected between the base of the PN transistor Q5 and turned on / off by a control signal S, and a collector, an emitter and a base of the fifth NPN transistor Q5, the second wiring VSS, and And a sixth NPN transistor Q6 connected to the collector of the fourth NPN transistor Q4.

According to the second aspect, when the constant current source 10A is turned off by the control signal S, the base current and collector current I5 of the fifth NPN transistor Q5 become 0, and power saving is achieved. In the third aspect of the first invention,
For example, as shown in FIG. 4, the constant current source 10A includes a current mirror circuit 13 that supplies a second current proportional to the first current to the base of the fifth NPN transistor Q5 and the collector of the sixth NPN transistor Q6. The first current is turned on / off by the control signal S, and the switch circuit 14 keeps the first current substantially constant when turned on.

The semiconductor device of the second invention has any one of the above reference voltage generation circuits.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 shows a reference voltage generating circuit according to the first embodiment. The reference voltage generating circuit is a part of a semiconductor integrated circuit used in, for example, a mobile phone.

The collector of the NPN transistor Q1 and the collector of the NPN transistor Q2 are connected to the output wiring VRR via resistors R1 and R2, respectively. The emitter of the NPN type transistor Q1 and the emitter of the NPN type transistor Q2 are connected to the collector of the NPN type transistor Q3 directly and via the resistor R3, respectively. The emitter and base of the NPN type transistor Q3 are connected to the ground line VSS and the collector of the NPN type transistor Q2, respectively.

The output voltage VRR is VRR = VBE (Q3) + (R2 / R3) ΔVBE (3) Where ΔVBE is the NPN transistor Q
VBE is the difference between the base-emitter voltage of 2 and the base-emitter voltage of the NPN transistor Q1.
(Q3) is the base-emitter voltage of the NPN transistor Q3. By making the output voltage VRR equal to the bandgap voltage when the ratio N of the collector current I1C of the NPN transistor Q1 and the collector current I2C of the NPN transistor Q2 is greater than 1 and constant. , The temperature drift of the output voltage VRR theoretically becomes zero.

A constant current source 10 is connected between the output wiring VRR and the power supply line VCC, a constant current I0 is supplied from the constant current source 10 to the main body 20, and resistors R1 and R2 are provided.
The currents I1 and I2 flowing through are constant. However, when the current I0 changes due to the temperature change of the semiconductor substrate, the currents I1 and I2 change, the base current IB3 of the NPN transistor Q3 also changes, and a difference occurs between the collector current I1C and the collector current I2C. The current density ratio N changes, which causes the output voltage VRR to change.

Therefore, even if the current I0 changes, IC1 = I
In order to establish 2C, R1 = R2 and NPN transistor Q4 having the same characteristics as NPN transistor Q3.
Of the NPN transistor Q1 is connected to the collector of the NPN transistor Q1, the emitter of the NPN transistor Q4 is connected to the ground line VSS, and the collector of the NPN transistor Q4 is connected to the output wiring VRR via the resistors R5 and R6. There is. Further, the base of the NPN transistor Q1 and the base of the NPN transistor Q2 are both connected to the connection point of the resistors R4 and R5, and the NPN transistor Q is connected.
The resistance values of the resistors R4 and R5 are determined so that the current flowing in 3 becomes equal to the current flowing in the NPN transistor Q4.

The NPN transistor Q3 functions so that the currents I1 and I2 are constant. That is, the current I
When 2 increases, the emitter potential of the NPN transistor Q1 decreases and the current I1 also increases. In addition, the current I1 increases to increase the base potential VRR of the NPN transistor Q4.
-When I1 and R1 decrease, NPN transistor Q4
Collector current I4 of the NPN transistor Q
The base potentials VRR-I4.R4 of 1 and Q2 rise and the currents I1 and I2 increase. However, since the base potential VRR-I2 · R2 of the NPN transistor Q3 decreases, the collector current of the NPN transistor Q3 decreases, and the currents I1 and I2 decrease, the currents I1 and I2 decrease.
Feedback control is performed so that 2 becomes constant.

In the first embodiment, even if the currents I1 and I2 change due to the change in the current I0 supplied to the main body 20, the current IB4 flowing from the resistor R1 to the base of the NPN transistor Q4 and the resistor R2 change. Since the current IB3 flowing through the base of the NPN type transistor Q3 becomes equal to each other, the collector current I1C of the NPN type transistor Q1.
And the collector current I2C of the NPN transistor Q2 become equal to each other, and the current density ratio N becomes constant,
The output voltage VRR becomes constant. Further, the output voltage VRR is controlled to be more constant by the feedback control.

[Second Embodiment] FIG. 2 shows a reference voltage generating circuit according to a second embodiment. In the main body 20A, the collector of the NPN transistor Q4 is connected to the output wiring VRR via the resistor R6, and the output wiring VRR and the ground line VS are connected.
The voltage division between the resistor R4 and the resistor R5 connected in series with S is supplied to the base of the NPN transistor Q1 and the base of the NPN transistor Q3. Other points are
The configuration is the same as that of FIG. 1, and obviously the same effect as in the case of FIG. 1 is obtained.

[Third Embodiment] FIG. 3 shows a reference voltage generating circuit according to a third embodiment. In this circuit, in order to save power by setting the current supplied to the main body 20 to 0 in the standby mode, the collector and the emitter of the NPN transistor Q5 are connected to the power supply line VCC and the output line VRR, respectively.
A constant current source 10A that is turned on / off by a control signal S is connected between the power supply line VCC and the base of the NPN transistor Q5. In addition, the constant current source 1
In order to pass an extra output current of 0 A to the ground line VSS side and prevent this current from affecting the output voltage VRR, the collector, emitter and base of the NPN transistor Q6 are respectively the base of the NPN transistor Q5, Ground line VSS and NPN type transistor Q4
Connected to the collector.

In the above configuration, when the constant current source 10A is turned off by the control signal S, the NPN transistor Q5
The base current and collector current I5 of 0 become 0, and power saving is achieved. Also, due to the change in the current I0, the current I5
Even if the value of VRR changes, the output voltage VRR is prevented from fluctuating due to the reason described in the first embodiment. [Fourth Embodiment] FIG. 4 shows a reference voltage generating circuit according to the fourth embodiment.

In this circuit, the constant current source 10A is composed of a current mirror circuit 13 and a switch circuit 14. The current mirror circuit 13 includes a PNP type transistor Q7 and a PNP type transistor Q8, and a switch circuit 14 has Darlington-connected NPN type transistors Q9 and Q10, a resistor R6 for increasing the input impedance, and an NPN type transistor. It comprises a resistor R7 for applying a base voltage to Q10. Also, N
Between the collector and emitter of the PN transistor Q6,
A capacitor C for compensating the phase and preventing oscillation is connected. The other points are the same as in the third embodiment.

In the above structure, when the control signal S is set to a high level, the NPN type transistors Q9 and Q10 are turned on, a constant collector current flows in the PNP type transistor Q7, and a collector current proportional to this is generated in the PNP type transistor Q8. Flow to. When the control signal S is set to a low level, the NPN type transistors Q9 and Q10 are turned off, the PNP type transistors Q7 and Q8 and the NPN type transistor Q5 are also turned off, and I0 = 0.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a reference voltage generation circuit according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a reference voltage generation circuit according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a reference voltage generation circuit according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a conventional reference voltage generation circuit.

FIG. 6 is a diagram showing another conventional reference voltage generation circuit.

[Explanation of symbols]

 10, 10A constant current source 20, 20A main body 13 current mirror circuit 14 switch circuit

Claims (5)

[Claims] 1. The collector of the first NPN type transistor and the collector of the second NPN type transistor are respectively the first
A resistor and a second resistor are both connected to the first wiring, and the emitter of the first NPN transistor and the second NPN are connected.
The emitter of the N-type transistor is connected directly and via the third resistor to the collector of the third NPN-type transistor, and the emitter and base of the third NPN-type transistor are connected to the second wiring and the collector of the second NPN-type transistor, respectively. An emitter and a base of the fourth NPN transistor are connected to the second wiring and a collector of the first NPN transistor, respectively, and a collector of the fourth NPN transistor is connected to the first wiring through a fourth resistor, The base of the first NPN-type transistor and the base of the second NPN-type transistor are set to a substantially constant same potential, and a current supply means for supplying a substantially constant current is connected to the first wiring, and the first resistor and the first resistor are connected. The resistance values of the two resistors are substantially equal to each other, and the collector current of the second NPN transistor is the current. The ratio of the density to the current density of the collector current of the first NPN type transistor is greater than 1, the characteristics of the third NPN type transistor and the fourth NPN type transistor are substantially equal to each other, and the first wiring and the second wiring are In the meantime, a reference voltage generating circuit, which outputs a voltage substantially equal to an energy gap of a semiconductor forming the first, second and third NPN transistors as a reference voltage. 2. The collector of the fourth NPN transistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the bases of the first and second NPN transistors on the one hand, On the other hand, the reference voltage generation circuit according to claim 1, wherein the reference voltage generation circuit is connected to the second wiring via a fifth resistor. 3. The current supplying means includes a fifth NPN transistor having a collector and an emitter connected to a power supply line and the first wiring, respectively, and between the power supply line and the base of the fifth NPN transistor. A constant current source that is connected and is turned on / off by a control signal, and a collector, an emitter, and a base are each the fifth NPN.
-Type transistor base, the second wiring and the fourth N
A sixth NPN connected to the collector of a PN transistor
3. The reference voltage generation circuit according to claim 1, further comprising a type transistor. 4. The constant current source includes a current mirror circuit for supplying a second current proportional to the first current to the base of the fifth NPN transistor and the collector of the sixth NPN transistor, and the first mirror according to a control signal. 4. The reference voltage generation circuit according to claim 3, further comprising a switch circuit that turns on / off the current and makes the first current substantially constant when the current is on. 5. A semiconductor device comprising the reference voltage generation circuit according to claim 1. Description: