JPH03180915A - Reference voltage generating circuit - Google Patents

Abstract

PURPOSE:To obtain a circuit reducing the number of elements and its reactive current by setting up the offset voltage of a differential amplifier as a reference voltage by using a constant voltage generating circuit and a voltage detecting circuit. CONSTITUTION:The differential input stage of a differential amplifier is formed by transistors(MOS type FETs) 11 to 14 and a constant current circuit 15 and the output of the differential input stage is received by an output circuit 16 to form a differential amplifier. When transistors(TRs) 11, 12 are fed back by resistors 17 to 19, an offset voltage to be the difference between the gate- source voltage of the TR 11 and the gate-source voltage of the TR 12 is amplified by the resistors 17 to 19. Since the offset voltage of the differential input part is fed back to the MOS FETs 11 to 14 and inputted as the reference voltage, the reference voltage generating circuit reducing the reactive current and the number of elements and generating the stable reference voltage can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a reference voltage generation circuit used in a constant voltage generation circuit, a voltage detection circuit, etc., and in particular to a reference voltage generation circuit that can realize a stable power supply circuit. Regarding circuits.

[Conventional technology]

Conventionally, MOS (Metal Oxide Sem1
The configuration of the reference voltage circuit used in a conductor-type semiconductor integrated circuit is a MOS-type FET (Field
Two or more effect transistors (or) are connected in series, and a reference voltage with good characteristics is generated at the connection point.

For example, in the constant voltage circuit shown in FIG. 2, the reference voltage generation circuit 2
It receives the output of 9 and amplifies the voltage and current. Further, the voltage detection circuit shown in FIG. 3 also performs voltage detection by receiving the output of the reference voltage generation circuit 39 at the differential amplifier circuit 30. In addition, in the 21st evening 1, 26
is an output M path, 27.28 is a single resistor, 31 to 34 are MOS transistors, 35 is a constant current circuit, and 37.38 is a resistor.

Related circuits of this type include, for example, Japanese Unexamined Patent Publication No. 5
6-108258.

[Problems to be Solved by the Invention] In the prior art described in section 2, when using a base i'11i voltage oscillator circuit, the problem of high output impedance usually occurs, so the voltage is and current amplification.

However, such a circuit is wasteful in terms of current consumption and number of elements, and has problems in terms of efficiency.

An object of the present invention is to improve such problems, to obtain a stable reference voltage with less reactive current and fewer elements, and to provide a reference voltage (offset voltage) with good temperature characteristics, or An object of the present invention is to provide a reference voltage generation circuit that can realize a reference voltage that is not affected by variations in threshold voltage.

[Means to solve the problem]

Ir, in order to achieve the objective, the reference voltage I of this defense is
The F generation circuit uses MOS transistors, and is a semiconductor device equipped with a differential amplifier and a voltage detection resistor. It is characterized by having the means.

In addition, the differential input section 2 is characterized in that MnS type FETs of the same conductivity type but different threshold levels are installed, and an offset voltage is generated by the threshold level difference of the MOSO3 type T.

Further, the differential input section (-) is characterized in that it is equipped with MO8 FETs of the same conductivity type but of different transistor sizes, and that an offset voltage is generated depending on the size ratio.

[Operation] In the present invention, standard 71! JT: A configuration that incorporates a generation circuit and an internal differential amplifier for the purpose of amplifying the voltage and current of the base 1'Pi voltage generated by the reference voltage generation circuit. This reduces reactive current and the number of elements, resulting in a stable base 1'I! Can generate voltage.

Further, when configuring a differential amplifier, by using two types of MOSO3 type Ts of the same conductivity type with different threshold levels, a reference voltage with good temperature characteristics can be realized.

Furthermore, by using MO8 type FETs with the same threshold level and different sizes, it is possible to realize a 'J+';i'1' voltage that is not affected by variations in threshold voltage.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a voltage power supply circuit according to the first embodiment of the present invention.

In Fig. 1, 11 to 14 are transistors (MO8 type FET), 15 is a constant current circuit, +6 is an output circuit, and 17 to
19 is a resistance. Further, the transistor 11 and the transistor star 12, and the transistor 13 and the transistor 1/l have the same conductivity type and have different threshold voltages.

With these transistors 11 to 14 and constant current circuit 15,
A differential input stage of a differential amplifier is formed.

Further, by receiving the output of this differential input stage at the output circuit 16, one differential amplifier is formed.

Furthermore, resistors 17-19 provide transistors 11.1.
By applying feedback to 2, the gate-source voltage V of the transistor 11 is increased. 84. and the gate-source voltage Vc8t2 of the transistor 12 (Vcsu Va
The offset voltage which is sJ is set by the resistor (R1?~R,,)
Amplify by 1.7-19.

As a result, the voltage V at the OUT terminal. , JT is Vour
−(Vcsu Vcsu)(R,, +R,, +R,,
)/R,.

...(1) becomes.

Here, the threshold level and flowing drain current of transistors 11 and 12 are set to VTH45 and VTH45, respectively.
Assuming VTl, +7, and 'jl+'u, the following equation (2) and (
3) Equation is obtained.

I n- ++ (Vcs++ VTHJ' -(
2) I u-Ku (Vasj2%'ru*) ' ・
...(3) However, K1. and 12 is the conductivity coefficient.

Here, the conductivity coefficients of transistors 11 and 12 are 1. .

K, 2 are designed the same, and transistors 13゜14
If the conductivity coefficient and threshold voltage of are also designed to be equal, then K It =K 12, l1l-112,
From equations (2) and (3), equation (4) shown below is obtained.

vas, 2VC811=VT) 1.2VTHII"'
(4) Here, V G31ffi V c1181 is the offset voltage, but this value is V THu V
THII is the difference in the threshold voltage of the terminal lever transistors 11 and 12, and the temperature characteristics are almost the same for threshold levels of the same conductivity type, so the reference voltage V REF =V THlf has extremely good temperature characteristics.
f V THII...(5) is obtained.

Therefore, by substituting equations (4) and (5) into equation (1), it is possible to realize a constant voltage power supply with extremely good temperature characteristics that is independent of power supply fluctuations as shown in equation (6).

■. UT = V R or F (R,, +R,, ten R,,)
/R, . . . (6) Note that R5 and R1 may each be OΩ.

FIG. 4 is a configuration diagram of a voltage detection circuit in a second embodiment of the present invention.

In FIG. 4, 41 to 44 are transistors (MO8 type FET), 45 is a constant current circuit, 46 is an output circuit, and 47 to
49 is a resistance. Further, the transistor 41 and the transistor 42, and the transistor 43 and the transistor 44 are of the same conductivity type, and have different threshold voltages.

In this embodiment, the power supply voltage V. T) value and reference voltage VRE
F is compared and a signal is output to the output terminal OUT. In this case, the reference voltage vR is the difference between the threshold voltages of the transistors 41 and 42 (v7H4°vTH4,), and as in the first embodiment, a reference voltage with extremely good temperature characteristics can be obtained.

FIG. 5 is a configuration diagram of a shunt type constant voltage power supply circuit according to a third embodiment of the present invention.

In FIG. 5, 51 to 54 are transistors (MO8 type FET), 55 is a constant current circuit, 56 is an output circuit, and 57 to 54 are transistors (MO8 type FET).
59 is a resistance. Further, the transistor 51 and the transistor 52, and the transistor 53 and the transistor 54 are of the same conductivity type, and have different threshold voltages.

In addition, in the first to third embodiments, as a differential amplifier, N
The circuit with MO8 input is shown, but it is a PMOS with P-N reflection.
It may also be a type that has an input.

In addition, as for how to generate the offset voltage, the input NMO
In addition to the method of using S with different threshold voltages, for example, the PMOS transistor 13 shown in FIG.
, 14, it is also possible to change the threshold level, such as by changing the threshold voltages of the transistors 43 and 44 in FIG. 4 and the transistors 53 and 54 in FIG. Furthermore, transistor 11 and transistor 12 (
or transistor 13 and transistor 14), the fourth
It is also possible to configure transistors 41 and 42 (or transistors 43 and 44) in the figure, and transistors 51 and 52 (or transistors 53 and 54) in FIG. 5 to be of the same conductivity type with different transistor sizes. .

〔Effect of the invention〕

According to the present invention, since the constant voltage generation circuit and the voltage detection circuit use the offset voltage of the differential amplifier as the reference voltage, elements and current consumption for creating the reference voltage are unnecessary, the number of elements is small, and A circuit with less reactive current can be realized.

Furthermore, by creating an offset voltage based on the difference in the threshold voltages of two types of MO8 type FETs of the same conductivity type, it is possible to use it as a reference voltage with little temperature fluctuation.

In addition, MOSs of the same conductivity type with the same threshold voltage
By using a type FET and creating it with a transistor size ratio, it is possible to use it as a reference voltage that is less affected by variations in threshold voltage.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a constant voltage power supply circuit according to a first embodiment of the present invention, and FIG. 2 is a diagram of a conventional constant voltage power supply circuit. Block diagram of the power supply circuit,
FIG. 3 is a configuration diagram of a conventional voltage detection circuit, FIG. 4 is a configuration diagram of a voltage detection circuit in a second embodiment of the present invention, and FIG. 5 is a configuration diagram of a shunt type in a third embodiment of the present invention. FIG. 3 is a configuration diagram of a voltage power supply port. 11-14.21-2/1.31-34.4I-44.
51-54: Transistor (MOS type FET), 15
, 25, 35, 45, 55: constant current circuit, 16, 26,
36, 46, 56: Output circuit. 17-19, 27, 28, 37, 38.47-49゜5
7-59: Resistance, 20, 30: Differential amplifier circuit. 3 Figure 0 Figure 111111

Claims (3)

[Claims] (1) In a semiconductor device using MOS transistors and equipped with a differential amplifier and a voltage detection resistor, means for inputting an offset voltage of a differential input section of the differential amplifier to the differential amplifier as a reference voltage. A reference voltage generation circuit characterized by comprising: (2) The differential input section is equipped with MOS FETs of the same conductivity type but different threshold levels, and the MOS FET
2. The reference voltage generating circuit according to claim 1, wherein the offset voltage is generated by an ET. (3) The differential input section is equipped with MOS FETs of the same conductivity type but different transistor sizes, and the MOS type FE
2. The reference voltage generating circuit according to claim 1, wherein the offset voltage is generated by T.