JPS60252929A - Reference voltage generating circuit - Google Patents

Abstract

PURPOSE:To obtain an optional stabilized output voltage level from variation of a resistance ratio between a collector and an emitter, by connecting the bases of transistors to each other after inserting a diode between a current source and a voltage stabilizing circuit of a band gap reference type voltage generating circuit. CONSTITUTION:The voltage of a resistance R5 is set so that an approximately equal level is obtained between a current I3 flowing to a transistor TRQ4 and a current I4 flowing to a TRQ5. Thus the base-emitter voltage VBE4 of the TRQ4 is equal to that of the TRQ5. Therefore the voltage VR5 obtained at both ends of a resistance R5 is equal to the output voltage V1 of a circuit VG. While the voltage V0 of an output terminal OUT is equal to VR5.R4/R5. In this case, V1 means the output of the circuit VG, i.e., a band gap reference type voltage generating circuit and is stable to the variation of temperatures.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a reference voltage generation circuit, and in particular to a reference voltage generating circuit that uses a stabilized voltage circuit such as a bandgap reference type and allows the output voltage to be set arbitrarily. Regarding generation circuits.

(Prior Art) FIG. 4 shows a conventional band gap reference type temperature compensated reference voltage generation circuit. In the same figure, Q +
, Qt, and Qs are NPli type transistors, and in particular, transistors QI and Q constitute a kind of current mirror circuit. R1 is a resistor that determines the current flowing through the diode-connected transistor Q1;
2 and R1 are resistors set so that the temperature gradient of the reference output voltage v0 becomes, for example, zero. IS is a current source that supplies current to such a reference voltage generation circuit.

In the circuit of FIG. 4, since the circuit of transistors Q1 and Qt constitutes a current mirror, the current 1. and ■2
The value of the ratio It/1g remains constant regardless of temperature. In addition,
This current ratio 1 +/I z has a value larger than 1.

If the voltage across the resistor R5 is Vll, then ■. =Vllll! l VIIE□ ... (11, but this is because the base-emitter voltage ■□ and vIIE□ of each transistor Q1 and Q2 are respectively. Also, the voltage ■R□ across the resistor R8 is therefore the reference The voltage output V0 is v, = Vl123 + vxz. Here, since the base-emitter voltage v mts of the transistor Q3 has a negative temperature characteristic (approximately -2 mV/℃), I + / I z and R1 / R3 By appropriately selecting the value of , the first term and the second term in equation (6)
The temperature characteristics of the term cancel out and the reference voltage output ■.

For example, the temperature characteristics of can be set to zero.

However, in the circuit of FIG. 4, as is clear from equation (6), the output is ■. so that the temperature characteristics of I/I/
When the values of I* and R1/R3 are determined, the magnitude of the reference voltage output v0 naturally becomes a determined value, which is disadvantageous in that it is not possible to obtain an arbitrary output voltage under the condition that the temperature characteristic is zero.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problems of the conventional type described above.
The present invention is based on the concept of using a voltage magnification changing circuit constituted by a transistor, a resistor, etc. in a reference voltage generation circuit, and the objective is to make it possible to obtain an arbitrary temperature-compensated output voltage with a simple circuit configuration.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has a first terminal and a second terminal, and a power supply current is supplied to the first terminal via a current source circuit. , a voltage stabilizing circuit that outputs a stabilized voltage from the first terminal, a diode circuit inserted in a forward direction between the first terminal of the voltage stabilizing circuit and the current source circuit, and the diode circuit and the current. A transistor whose base is connected to a connection point with a source circuit and whose emitter is connected to a second terminal of the voltage stabilizing circuit via an impedance element, and a circuit that generates an output voltage according to the current flowing through the transistor. A reference voltage generation circuit is provided.

(Function) In the present invention, by using the above-described configuration, the voltage obtained by a reference voltage generation circuit such as a bandgap reference type is converted according to the ratio of the resistances of two resistors. Since it can be output, it becomes possible to generate a reference voltage that is temperature compensated and has an arbitrary voltage value.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows a reference voltage generation circuit according to one embodiment of the present invention. The circuit shown in FIG. 4 is obtained by adding transistors Q 4 , Q s and resistors R, , R, to the circuit shown in FIG. 4. In other words, the circuit VC surrounded by the dashed line
and the current source circuit Is is the same as that of the circuit in FIG.
A diode-connected transistor Q4 is inserted between these current sources IS and the circuit VC. The base of the transistor QS is connected to the connection point between the current source circuit is and the transistor Q4, that is, the collector and base of the transistor Q4. Transistor Q.

The emitter of is grounded via a resistor R3, and the collector is connected to the power supply Vcc via a resistor R4.

Note that the transistors Q4 and Q5 are of the same size, for example.

In the circuit shown in FIG. 1, if the value of resistor R7 is set so that the current i flowing through transistor Q4 and the current ■4 flowing through transistor Q are approximately equal, the base-emitter voltage V 114 of each transistor Q4 and Q is set. and ■□ are equal. Therefore, the voltage ■□ across the resistor R2 becomes equal to the output voltage ■1 of the circuit VG. Also,
Voltage ■ between the output terminal OUT, that is, the collector of the transistor Q5 and the power supply Vce. and voltage ■. There are 4 ■ between them. −□■□ ...(7) There is the following relationship. Therefore, 4 ■. =□■, ...(8) R3 In the above equation, the voltage ■ is the output of the circuit VG, that is, the bandgap reference type reference voltage generation circuit, and as mentioned above, it is stabilized against temperature changes. Therefore, the voltage in the chamber ■. Since the value of is determined by the ratio of the resistors R4 and Rs and the voltage ■1, the voltage ■. Also, the voltage is stabilized against temperature changes. Also, the voltage ■. The value of resistor R4
By changing the ratio of R3 and R3, it is possible to set it to an arbitrary value. Therefore, by using the circuit shown in FIG. 1, it is possible to obtain a stabilized output voltage of any voltage.

FIG. 2 shows a reference voltage generation circuit according to another embodiment of the present invention. The circuit shown in the same figure has a transistor Q4 in addition to the circuit shown in FIG. Q! A transistor Q having the same characteristics as 1 and resistors Rh and R'r are added.

In the circuit of FIG. 2, each transistor Qa.

Current flowing through Q s, Q h 13. Resistors R1 and R? so that In and Is are equal. When the value of is set, the base-emitter voltage of each transistor Qa, QS, and Q6 becomes VB! 4+ ■BE%+ ■□6 become equal. Therefore, each of these transistors Q a, Q s,
The voltage between the emitter of Q h and ground Vl, VIS
, Vat are all equal, so each output voltage V, ,
,V. 8 will be each. As is clear from these equations, two types of independent reference voltages can be created by setting the resistors R4 and R1 and the ratio of R4 and R1. , and ■
. You can get 2.

FIG. 3 shows a reference voltage generation circuit according to still another embodiment of the present invention. The circuit of the same figure uses a diode-connected PNP type transistor Q in place of the collector resistor R4 of the transistor Q in the circuit of FIG.
type transistor Q, a PNP type transistor Q whose base and emitter are each commonly connected, and a resistor R4 connected between the collector of the transistor Q and the ground.
is added. The other parts are the same as the circuit of FIG. 1, and the same parts are given the same reference numerals. Note that the transistors Q and Q are of the same size, for example.

In the circuit of FIG. 3, the voltage (2) across the resistor R3 is the same as in the circuits of the respective embodiments described above. becomes equal to the reference voltage ■1 which is stable with respect to temperature. In addition, transistors Q7 and Q,
constitutes a current mirror circuit, so the current (4) flowing through the resistor R3 and the current (2) flowing through the resistor R4 are equal.

Therefore, it becomes. That is, it becomes possible to obtain a reference voltage stable with respect to temperature with respect to the ground potential, and its magnitude can be arbitrarily set by the ratio of resistors R3 and R4. In the circuit of FIG. 3, it is also possible to connect a plurality of circuits similar to the circuit consisting of the transistor Q and the resistor R4 to the base of the transistor Q7 to obtain a plurality of types of reference voltages.

(Effects of the Invention) As described above, according to the present invention, with a simple circuit configuration,
It becomes possible to obtain a stabilized output voltage of any voltage, and it becomes possible to further expand the range of applications of temperature-compensated reference voltage generation circuits such as band gap reference type. Further, according to the present invention, it is possible to output reference voltages of arbitrary values in multiple systems by adding a small number of components.
It becomes possible to simplify the circuit configuration of the reference voltage generation circuit and reduce costs.

44. Brief Description of the Drawings FIGS. 1, 2, and 3 are electrical circuit diagrams showing a reference voltage generation circuit according to an embodiment of the present invention, and FIG.
The figure is an electrical circuit diagram showing a conventional reference voltage generation circuit.

Q,,Q,,...,Qll:) transistor,R,,R
,,...1 R7: Resistor, IS: Current source circuit.

patent applicant Fujitsu Limited patent application agent Patent Attorney Akira Aoki Patent attorney Kazuyuki Nishidate Lawyer Yukio Uchida Patent attorney Akira Yamaguchi Figure 2 cc Figure 3 cc

Claims (1)

[Claims] 1. It has a first and a second terminal, a power supply current is supplied to the first terminal via a current source circuit, and a stabilized voltage is output from the first terminal. a voltage stabilizing circuit, a diode circuit inserted in one direction between a first terminal of the voltage stabilizing circuit and the current source circuit, a base connected to a connection point between the diode circuit and the current source circuit, and an emitter; A reference voltage generating circuit comprising: a transistor connected to a second terminal of the voltage stabilizing circuit via an impedance element; and a circuit that generates an output voltage according to a current flowing through the transistor. 2. Claim 1 in which the diode circuit is constituted by a transistor whose collector and base are connected.
The reference voltage generation circuit described in .