JPH05249151A - Overcurrent detection circuit - Google Patents
Overcurrent detection circuitInfo
- Publication number
- JPH05249151A JPH05249151A JP4687192A JP4687192A JPH05249151A JP H05249151 A JPH05249151 A JP H05249151A JP 4687192 A JP4687192 A JP 4687192A JP 4687192 A JP4687192 A JP 4687192A JP H05249151 A JPH05249151 A JP H05249151A
- Authority
- JP
- Japan
- Prior art keywords
- current
- temperature characteristic
- circuit
- detection voltage
- negative
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/32—Compensating for temperature change
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
(57)【要約】
【目的】 電流検出電圧の温度特性を調整できる過電流
検出回路を得る。
【構成】 電流検出電圧を発生する抵抗を流れる電流が
正（又は負）の温度特性を持つ電流と、負（又は正）の
温度特性をもつ電流との加算として電流検出電圧の温度
特性を調整する電流回路を備える。
(57) [Abstract] [Purpose] To obtain an overcurrent detection circuit that can adjust the temperature characteristics of the current detection voltage. [Composition] The temperature characteristic of the current detection voltage is adjusted by adding the current having a positive (or negative) temperature characteristic and the current having a negative (or positive) temperature characteristic to the current flowing through the resistor for generating the current detection voltage. A current circuit is provided.
Description
【０００１】[0001]
【産業上の利用分野】この発明は、スイッチングレギュ
レータの過電流検出回路、特にその温度特性を調整可能
とした過電流検出回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcurrent detection circuit for a switching regulator, and more particularly to an overcurrent detection circuit whose temperature characteristic can be adjusted.
【０００２】[0002]
【従来の技術】図２は従来のスイッチングレギュレータ
電源における過電流検出回路の回路図であり、図におい
て、１、２はトランジスタＱ４、Ｑ５で、外部検出電圧
と電流検出電圧とを比較して、外部検出電圧が電流検出
電圧より大きいとき、発振器を停止させ出力スイッチＯ
ＦＦとする機能を持つ回路を構成する。３、４、５はト
ランジスタＱ２、Ｑ３及び抵抗Ｒ０で、電流検出電圧を
発生させるための電流回路を構成する。６は抵抗Ｒ３
で、両端に電流検出電圧を発生する。７はバンドギャッ
プ基準電圧Ｖref である。2. Description of the Related Art FIG. 2 is a circuit diagram of an overcurrent detection circuit in a conventional switching regulator power supply. In the figure, reference numerals 1 and 2 denote transistors Q4 and Q5, which compare an external detection voltage with a current detection voltage. When the external detection voltage is higher than the current detection voltage, the oscillator is stopped and the output switch O
A circuit having a function of FF is configured. Reference numerals 3, 4, and 5 are transistors Q2 and Q3 and a resistor R0, which constitute a current circuit for generating a current detection voltage. 6 is resistance R3
Then, the current detection voltage is generated at both ends. Reference numeral 7 is a bandgap reference voltage Vref.
【０００３】次に動作について説明する。図２におい
て、電流検出電圧ＶIPK はＲ３の両端電圧であり、Next, the operation will be described. In FIG. 2, the current detection voltage V IPK is the voltage across R3,
【０００４】[0004]
【数１】 [Equation 1]
【０００５】となる。ここで、ＶBEQ2はトランジスタＱ
２のベース−エミッタ間電圧であり、ＶBEQ3はトランジ
スタＱ３のベース−エミッタ間電圧である。よって
（１）式よりＶIPK の温度特性は、[0005] Here, V BEQ2 is a transistor Q
V BEQ3 is the base-emitter voltage of the transistor Q3. Therefore, from the equation (1), the temperature characteristic of V IPK is
【０００６】[0006]
【数２】 [Equation 2]
【０００７】となる。ここで、２Ｖref ／２Ｔ＝０とし
た。[0007] Here, 2Vref / 2T = 0.
【０００８】[0008]
【発明が解決しようとする課題】従来の過電流検出回路
は以上のように構成されているので、ＶIPK の温度特性
はＲ３, Ｒ０の値を選ぶことによりその絶対値は可変で
あるが、極性は、正又は負, ０又は負のいずれかであ
り、調整不可能という問題点があった。Since the conventional overcurrent detection circuit is configured as described above, the absolute value of the temperature characteristic of VIPK can be changed by selecting the values of R3 and R0. The polarity is either positive or negative, 0 or negative, and there is a problem that it cannot be adjusted.
【０００９】この発明は上記のような問題点を解消する
ためになられたもので、抵抗地を選ぶことによって、極
性をも含めた形での電流検出電圧の温度特性を調整でき
る過電流検出回路を得ることを目的とする。The present invention has been made in order to solve the above problems, and by selecting a resistance ground, the overcurrent detection in which the temperature characteristic of the current detection voltage including the polarity can be adjusted. Aim to get the circuit.
【００１０】[0010]
【課題を解決するための手段】この発明に係わる過電流
検出回路の温度特性調整回路は、電流検出電圧を発生す
る抵抗を流れる電流が、正（又は負）の温度特性をもつ
電流と、負（又は正）の温度特性をもつ電流との加算と
して得られる電流回路を備えたものである。A temperature characteristic adjusting circuit of an overcurrent detecting circuit according to the present invention is characterized in that a current flowing through a resistor for generating a current detection voltage has a positive (or negative) temperature characteristic and a negative current. It is provided with a current circuit obtained as an addition with a current having a (or positive) temperature characteristic.
【００１１】[0011]
【作用】この発明における過電流検出回路の温度特性調
整回路は、正（又は負）の温度特性をもつ電流と、負
（又は正）の温度特性をもつ電流とを抵抗値を選ぶこと
によりある一定の比率で加算し、その電流により電流検
出電圧を発生させ、電流検出電圧の温度特性を抵抗値を
選ぶことによって調整する。The temperature characteristic adjusting circuit of the overcurrent detection circuit according to the present invention is such that the resistance value is selected between the current having the positive (or negative) temperature characteristic and the current having the negative (or positive) temperature characteristic. The current detection voltage is generated by adding the currents at a constant ratio, and the temperature characteristic of the current detection voltage is adjusted by selecting the resistance value.
【００１２】[0012]
実施例１．以下、この発明の実施例１を図について説明
する。図１はこの発明の実施例１による過電流検出回路
の回路図である。図において、２１, ２２はトランジス
タＱ４, Ｑ５で、外部抵抗ｒにより検出された電圧を電
流検出電圧（ＶIPK ）と比較し、ＶIPK より大きいとき
発振器を停止させ、出力スイッチをＯＦＦさせる信号を
発振器に送る機能を持つ回路を構成する。２３, ２４,
２５は負の温度特性をもつ電流回路を構成するトランジ
スタＱ２, Ｑ３及び抵抗Ｒ２, ２６ａ, ２６ｂは正の温
度特性をもつ電流回路を構成するトランジスタＱ１及び
抵抗Ｒ１, ２７は負の特性を持つ電流との加算された電
流により両端に電流検出電圧（ＶIPK）を発生する抵抗
Ｒ３、２８はバンドギャップ基準電圧Ｖref である。Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a circuit diagram of an overcurrent detection circuit according to a first embodiment of the present invention. In the figure, 21 and 22 are transistors Q4 and Q5, which compare the voltage detected by the external resistance r with the current detection voltage (V IPK ), and when the voltage is larger than V IPK , stop the oscillator and turn off the output switch. Configure a circuit that has the function of sending to the oscillator. 23, 24,
Reference numeral 25 is a transistor Q2, Q3 and resistors R2, 26a, 26b forming a current circuit having a negative temperature characteristic, and transistor R1 and resistors R1, 27 forming a current circuit having a positive temperature characteristic are currents having a negative characteristic. The resistors R3 and 28, which generate a current detection voltage (V IPK ) at both ends by the added current of the above, are the bandgap reference voltage Vref.
【００１３】次に動作について説明する。図１に示すよ
うに、Ｒ３に流れる電流を２つに分け、トランジスタＱ
３、抵抗Ｒ２を流れる電流をＩ１、トランジスタＱ２、
抵抗Ｒ１を流れる電流を１２とすると、Next, the operation will be described. As shown in FIG. 1, the current flowing through R3 is divided into two, and the transistor Q
3, the current flowing through the resistor R2 is I1, the transistor Q2,
If the current flowing through the resistor R1 is 12,
【００１４】[0014]
【数３】 [Equation 3]
【００１５】ここで、２Ｖref ／２Ｔ＝０とした。
（３）式より、ＶIPK の温度特性は、右辺第１項の０ま
たは負の温度特性と、右辺第２項の正の温度特性との加
算となり、抵抗Ｒ１、Ｒ２、Ｒ３の値を選ぶことによ
り、極性を含めた形での温度特性の調整ができる。Here, 2Vref / 2T = 0 is set.
From the equation (3), the temperature characteristic of V IPK is the addition of the 0 or negative temperature characteristic of the first term on the right side and the positive temperature characteristic of the second term on the right side, and the values of the resistors R1, R2, R3 are selected. This makes it possible to adjust the temperature characteristics including the polarity.
【００１６】実施例２．実施例１においては、過電流検
出電圧についてその温度特性の調整について説明した
が、この温度特性調整回路は、温度特性を制御する回路
一般について適用が可能である。Example 2. In the first embodiment, the adjustment of the temperature characteristic of the overcurrent detection voltage has been described, but the temperature characteristic adjusting circuit is applicable to general circuits that control the temperature characteristic.
【００１７】[0017]
【発明の効果】以上のようにこの発明によれば、電流検
出電圧を発生する抵抗を流れる電流が正（又は負）の温
度特性を持つ電流と、負（又は正）の温度特性をもつ電
流との加算として電流検出電圧の温度特性を調整する電
流回路を備えた構成としたので、温度特性の絶対値、極
性について調整できる効果がある。As described above, according to the present invention, the current flowing through the resistor for generating the current detection voltage has a positive (or negative) temperature characteristic and the current having a negative (or positive) temperature characteristic. Since the current circuit for adjusting the temperature characteristic of the current detection voltage is provided as the addition of the above, there is an effect that the absolute value and the polarity of the temperature characteristic can be adjusted.
【図１】この発明の実施例１による過電流検出回路の回
路図である。FIG. 1 is a circuit diagram of an overcurrent detection circuit according to a first embodiment of the present invention.
【図２】従来の過電流検出回路の回路図である。FIG. 2 is a circuit diagram of a conventional overcurrent detection circuit.
２１ トランジスタＱ４ ２２ トランジスタＱ５ ２３ トランジスタＱ２ ２４ トランジスタＱ３ ２５ 抵抗Ｒ２ ２６ａ トランジスタＱ１ ２６ａ 抗Ｒ１ ２７ 抵抗Ｒ３ ２８ バンドギャップ基準電圧Ｖｒｅｆ 21 transistor Q4 22 transistor Q5 23 transistor Q2 24 transistor Q3 25 resistor R2 26a transistor Q1 26a anti-R1 27 resistor R3 28 bandgap reference voltage Vref
Claims (1)
過電流検出回路において、電流検出電圧を発生する抵抗
を流れる電流が正（又は負）の温度特性をもつ電流と、
負（又は正）の温度特性をもつ電流との加算として電流
検出電圧の温度特性を調整する電流回路を備えたことを
特徴とする過電流検出回路。1. An overcurrent detection circuit in a switching regulator power supply, wherein a current flowing through a resistor for generating a current detection voltage has a positive (or negative) temperature characteristic,
An overcurrent detection circuit comprising a current circuit for adjusting a temperature characteristic of a current detection voltage as an addition with a current having a negative (or positive) temperature characteristic.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4687192A JPH05249151A (en) | 1992-03-04 | 1992-03-04 | Overcurrent detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4687192A JPH05249151A (en) | 1992-03-04 | 1992-03-04 | Overcurrent detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05249151A true JPH05249151A (en) | 1993-09-28 |
Family
ID=12759413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4687192A Pending JPH05249151A (en) | 1992-03-04 | 1992-03-04 | Overcurrent detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05249151A (en) |
-
1992
- 1992-03-04 JP JP4687192A patent/JPH05249151A/en active Pending
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