JPS6213020Y2

JPS6213020Y2 -

Info

Publication number: JPS6213020Y2
Application number: JP11386279U
Authority: JP
Priority date: 1979-08-18
Filing date: 1979-08-18
Publication date: 1987-04-03
Also published as: JPS5631365U

Description

【考案の詳細な説明】本考案は、電子機器の電圧比較回路に関するも
のである。[Detailed Description of the Invention] The present invention relates to a voltage comparison circuit for electronic equipment.

従来、電圧比較回路として第１図に示すものが
使われてきた。第１図の電源投入時の波形が第２
図であるが、電源投入時、被比較電圧V₂が不安
定なレベルになる時点でV₂＜Ｖ_REFとなり、電圧
比較器３の出力が反転してしまうことがあつた。 Conventionally, the voltage comparison circuit shown in FIG. 1 has been used. The waveform at power-on in Figure 1 is the second waveform.
As shown in the figure, when the power is turned on, when the voltage to be compared V ₂ reaches an unstable level, V ₂ <V _REF , and the output of the voltage comparator 3 is sometimes inverted.

本考案の目的は、上記した欠点をなくし、電源
投入時に基準電圧をある時間抑えることで、被比
較電圧が不安定な時期に電圧比較器の出力が反転
することがないようにすることである。 The purpose of this invention is to eliminate the above-mentioned drawbacks and to suppress the reference voltage for a certain period of time when the power is turned on, thereby preventing the output of the voltage comparator from inverting when the voltage to be compared is unstable. .

電源投入時、定電圧素子を利用し基準電圧Ｖ_RE
_Ｆを一定時間抑え、比較される電圧が安定してか
ら基準電圧Ｖ_REFを立ち上げ、電圧比較器の反転
を防止する。 When the power is turned on, the reference voltage V _RE is set using a constant voltage element.
_F is suppressed for a certain period of time and the reference voltage V _REF is raised after the voltage to be compared is stabilized to prevent the voltage comparator from inverting.

本考案の一実施例を第３図に、またその各電圧
の電源投入時の波形を第４図に示す。基準電圧Ｖ
_REFは、V₁電源が定電圧素子４の電圧Vzに達する
まで抑えられ、V₁＞Vzとなると立ち上りはじめ
る。そのため、V₂電圧のレベルが不安定な時期
がすぎてからＶ_REFを立ち上げることができるた
め電圧比較器３の出力が反転することを防ぐこと
ができる。 An embodiment of the present invention is shown in FIG. 3, and the waveforms of the respective voltages when the power is turned on are shown in FIG. Reference voltage V
_REF is suppressed until the V ₁ power supply reaches the voltage Vz of the constant voltage element 4, and starts rising when V ₁ >Vz. Therefore, V _REF can be raised after the period when the level of the V ₂ voltage is unstable has passed, so that the output of the voltage comparator 3 can be prevented from being inverted.

本考案によれば、電圧比較回路の基準電圧の立
ち上りを電源投入後の一定時間抑えることができ
るので、比較される電圧が電源投入時不安定にな
つても、電圧比較の出力が反転することがなくな
る。 According to the present invention, the rise of the reference voltage of the voltage comparator circuit can be suppressed for a certain period of time after the power is turned on, so even if the voltage to be compared becomes unstable when the power is turned on, the output of the voltage comparison circuit will not be reversed. disappears.

[Brief explanation of the drawing]

第１図は従来の電圧比較回路を示す回路図、第
２図は第１図における電源投入時の各電圧の立ち
上りを示す波形図、第３図は本考案の一実施例を
示す回路図、第４図はその各電圧の立ち上りを示
す波形図である。図において、１，２は分圧抵抗、３は比較器、
４は定電圧素子、５は電流制限用抵抗である。 FIG. 1 is a circuit diagram showing a conventional voltage comparison circuit, FIG. 2 is a waveform diagram showing the rise of each voltage when the power is turned on in FIG. 1, and FIG. 3 is a circuit diagram showing an embodiment of the present invention. FIG. 4 is a waveform diagram showing the rise of each voltage. In the figure, 1 and 2 are voltage dividing resistors, 3 is a comparator,
4 is a constant voltage element, and 5 is a current limiting resistor.

Claims

[Scope of utility model registration request]

A constant voltage element and a resistor are connected in series from the reference power supply _V1 , the other end of the resistor is grounded, and the voltage at the connection point of the constant voltage element and the resistor is used as the reference voltage and the voltage of the compared power supply _V2 . What is claimed is: 1. A voltage comparator circuit that compares a reference voltage with a voltage comparator using a voltage comparator, and is characterized in that a reference voltage is suppressed until a voltage to be compared reaches a certain level.