JP3403054B2 - Temperature characteristic correction circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature characteristic correction circuit for outputting a correction current according to a temperature characteristic of a transistor. [0002] Conventionally, there has been known a temperature characteristic correction circuit for outputting a correction current according to the temperature characteristic of a transistor as shown in FIG. The power supply Vcc for circuit operation includes:
The emitter of a PNP transistor Q1 whose collector and base are short-circuited is connected. Between the collector of this transistor Q1 and ground, a resistor R1 and a resistor R1 connected in series are connected.
2 (voltage dividing resistor) is connected. Therefore, the power supply voltage V
The voltage V1 = (Vcc−VBE) × R2 / (R1 + R2) obtained by dividing the voltage (Vcc−VBE) lower than cc by VBE by the resistors R1 and R2 is obtained at the connection point between the resistors R1 and R2. A power supply Vcc is connected to a power supply P via a resistor R4.
The emitter of the NP transistor Q3 is connected, and the collector of the transistor Q3 is connected to the ground via a constant current source CC1 for supplying a constant current IEE. The emitter of a PNP transistor Q2 whose collector is connected to the ground is connected to the base of the transistor Q3, and the base of the transistor Q2 is connected to the collector of the transistor Q3. Therefore, the current IEE basically flows through the resistor R4, and the voltage at the lower end of the resistor R4 is Vcc-I
EER3. Further, the voltage V0 at the collector of the transistor Q3 becomes a voltage V0 = Vcc-IEER3-2VBE lower than the voltage at the lower end of the resistor R3 by 2VBE. [0004] A resistor R3 is connected between a connection point between the resistors R1 and R2 that have the voltage V1 and the collector of the transistor Q3 that has the voltage V0. And, for example, 2
When the resistors R1 and R2 are set so that V0 = V1 at 5 ° C. (normal temperature), a current (ΔIH or ΔIH) corresponding to a change in VBE due to a change in temperature is applied to the resistor R3.
L) will flow. Here, the base of the transistor Q3 has:
Since the base of the PNP transistor Q4 whose emitter is connected to the power supply Vcc is connected to the collector of the transistor Q4, the current (ΔIH or ΔIL) flowing through the resistor R3 is added or subtracted to the current IEE according to the direction. The subtracted output current IEEOUT is obtained. Also, by changing the resistance value of the resistor R3, the output current IE
The temperature characteristics of EOUT can be set, and the temperature characteristics of various circuits can be corrected by the output current IEEEOUT. There is no problem if the power supply voltage Vcc does not fluctuate in the above circuit, but if the power supply voltage Vcc fluctuates, the output current IEEEOU
T fluctuates. Therefore, in the conventional circuit,
There has been a problem that the temperature characteristic cannot be corrected properly due to the fluctuation of the power supply voltage Vcc. The present invention has been made in view of the above problems, and has as its object to provide a temperature characteristic correction circuit capable of outputting a stable correction current even when the operating power supply voltage Vcc fluctuates. . According to the present invention, an end is connected to a reference power supply, and a short circuit occurs between a base and a collector.
A reference transistor for obtaining a voltage 1 VBE lower than the reference power supply at the other end, a first voltage-dividing resistor connected between the other end of the reference transistor and the ground for obtaining a first divided voltage at an intermediate point, It is connected between the ground, the intermediate
A second voltage dividing resistor for obtaining a second divided voltage at a point ; a setting resistor for flowing a correction reference current based on a difference between the first divided voltage and the second divided voltage; one end connected to an operating power supply; And an output transistor for outputting a correction current corresponding to the flowing correction reference current. [0009] With this configuration, the first divided voltage set by the first voltage dividing resistor corresponds to the VBE of the reference transistor, and the second divided voltage set by the second voltage dividing resistor. The voltage is independent of the transistor's VBE. Therefore, a current according to the temperature characteristics of the transistor VBE flows through the set resistor. Therefore, by outputting this current as a correction current, a temperature characteristic correction current can be obtained. The temperature characteristic correction current is irrelevant to the voltage of the operation power supply, and can be stabilized regardless of the voltage fluctuation of the operation power supply. Embodiments of the present invention (hereinafter, referred to as embodiments) will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the overall configuration of the present embodiment. This circuit has a reference power supply VREF essentially free from voltage fluctuation. And, this reference power supply VRE
PNP transistor Q whose base collector is short-circuited to F
The emitter of a transistor 11 (reference transistor) is connected, and a series connection (first voltage dividing resistor) of a resistor R11 and a resistor R12 is connected between the collector of the transistor 11 and the ground. Therefore, at the connection point between the resistors R11 and R12, V11 = (Vcc−VBE) × R12 / (R11 +
R12) is obtained. This resistor R11
The base of the PNP transistor Q12 is connected to the connection point of the PNP transistor Q12. The collector of the transistor Q12 is connected to ground, and the emitter is connected to the power supply Vcc via a resistor. The base of an NPN transistor Q13 is connected to the emitter of the transistor Q12. The collector of the transistor Q13 is connected to the power supply Vcc, and the emitter is connected to the ground via the constant current source CC11. Therefore, transistor Q1
A constant current basically flows through the constant current source CC11. A series connection of a resistor R13 and a resistor R14 (second voltage dividing resistor) is connected between the reference power supply VREF and the ground. Therefore, the resistors R13 and R1
V10 = Vcc × R14 / (R13 + R
14) is obtained. The connection point of the resistors R13 and R14 is connected to the base of a PNP transistor Q14. The collector of the transistor Q14 is connected to the ground, and the emitter is connected to the power supply V via a resistor.
Connected to cc. The base of an NPN transistor Q15 is connected to the emitter of the transistor Q14. The collector of this transistor Q13 is connected to a power supply Vcc via a PNP transistor Q16 whose base and collector are short-circuited, and the emitter is a constant current source CC12.
Connected to the ground via Therefore, a constant current basically flowing to the constant current source CC12 flows through the transistors Q15 and Q16. A resistor R15 (set resistor) is arranged between the emitters of the transistors Q13 and Q15. Since the potential at both ends of the resistor R15 rises by 1 VBE and then falls by 1 VBE, it becomes equal to V11 and V10. Therefore, a current based on the difference between the voltages V11 and V12 flows through the resistor R15. Further, the base of the transistor Q16 has a PN emitter connected to a power supply Vcc via a resistor.
The base of P transistor Q17 is connected (transistors Q16 and Q17 form a current mirror). The emitter of a PNP transistor Q18 is connected to the power supply Vcc via a resistor. The collector of the transistor Q18 has a constant current source C
The ground is connected via C13. The base of the transistor Q18 is provided with a PNP transistor Q19.
The collector of the transistor Q19 is connected to ground, and the base is connected to the transistor Q1.
8 collectors. Further, the base of the transistor Q18 is connected to the base of a PNP transistor Q20 (output transistor), and the emitter of the transistor Q20 is connected to the power supply Vcc via a resistor.
A correction current IEEEOUT is output from the collector. The collector of the transistor Q17 is connected to the collector of the transistor Q18, and the collector of the transistor Q17 is connected to the constant current source CC14.
Is connected. Therefore, the current flowing through the transistor Q15 flows through the transistor Q16, which is
7 flows. Here, the constant current sources CC11, CC12, CC
The current flowing through 14 is set the same. Therefore, if the current flowing through the transistor Q16 is the same as the current flowing through the constant current source CC12, all the current flowing through the transistor Q17 flows through the constant current source CC14. Here, V11 at normal temperature (25 ° C.)
And V10 are equal, so that the resistors R11, R12, R
13 and R14. Therefore, at normal temperature, no current flows through the resistor R15. When the temperature changes, a difference occurs between the voltages V11 and V10 across the resistor R15 according to the temperature characteristics of the transistor Q11.
The current of the resistor R15 flows. If the current flowing through the resistor R15 at high temperature is ΔIH and the current flowing at low temperature is ΔIL, the directions are opposite. Therefore, the current flowing through the transistors Q15, Q16, Q17 is
, And the amount of the change is added to the current flowing through the transistor Q18. That is, the current flowing through the transistor Q18 is basically the current IEEE flowing through the constant current source CC13,
When a current flows through the resistor R15, the current ΔIH flowing here
Alternatively, a current obtained by adding ΔIL to the current IEEE flows through the transistor Q18. The current flowing through the transistor Q18 is directly applied to the transistor Q20.
As an output current IEEEOUT. As described above, according to the circuit of this embodiment,
Similarly to the above-described conventional example, the current ΔI (ΔIH or ΔIL) corresponding to the transistor VBE can be output as an output current IEEOUT obtained by adding the current IEE.
The current ΔI can be adjusted by setting the resistance value of the resistor R15. As described above, according to the circuit of this embodiment,
By setting the resistance values of the resistors R11, R12, R13, and R14 and changing the resistance value of the resistor R15, the output current I
It is possible to obtain a correction current IEOUT obtained by adding an arbitrary coefficient of VBE to EEOUT. Then, the output correction current IEEEOUT becomes irrelevant to the power supply voltage Vcc. Therefore, it is possible to provide a temperature characteristic correction circuit that can output a correction current that is not affected by a change in the power supply voltage Vcc. In particular, the power supply Vcc for operating the IC
The circuit is liable to fluctuate due to the operation of the circuit, and this circuit can eliminate the adverse effect caused by the fluctuation of the operation power supply. In the circuit shown in FIG. 1, if the transistor Q16 is arranged upstream of the transistor Q13 instead of upstream of the transistor Q15, it is possible to obtain a correction current IEEOUT whose characteristics with respect to temperature are opposite. As described above, according to the present invention,
It is possible to provide a temperature characteristic correction circuit in which the correction current is not affected even when the voltage of the operation power supply changes.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing a configuration of an embodiment. FIG. 2 is a circuit diagram showing a conventional configuration. [Description of Signs] VREF Reference power supply, Vcc power supply, Q11 to Q20
Transistors, R11-R15 resistors.

Claims (1)

(57) Patent Claims 1. A one end connected to the reference power supply, the base Kore
A reference transistor to obtain a voltage at the other end of drops 1VBE from the reference power by between Kuta is shorted, it is connected between the other end and ground of the reference transistor, the first to obtain a first divided voltage at a midpoint a voltage dividing resistor is connected between the reference power and ground, a second midpoint
A second voltage dividing resistor for obtaining a divided voltage; a setting resistor for flowing a correction reference current based on a difference between the first divided voltage and the second divided voltage; a correction reference current having one end connected to the operating power supply and flowing through the setting resistor And an output transistor that outputs a correction current according to the temperature characteristic correction circuit.