JPH03110562U - - Google Patents
Info
- Publication number
- JPH03110562U JPH03110562U JP1830890U JP1830890U JPH03110562U JP H03110562 U JPH03110562 U JP H03110562U JP 1830890 U JP1830890 U JP 1830890U JP 1830890 U JP1830890 U JP 1830890U JP H03110562 U JPH03110562 U JP H03110562U
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- light source
- emitting elements
- light emitting
- resistor
- 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.)
- Granted
Links
- 238000010586 diagram Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 2
Description
第１図は本考案による光源駆動回路の一実施例
を示す回路図、第２図はこの実施例を用いた光学
情報読取装置の一例を示すブロツク図、第３図は
従来の光源駆動回路の一例を示す回路図、第４図
は乾電池の出力電圧の経時変化の試験結果を示す
グラフ図である。
１〜１０……ＬＥＤ、１８……光源、３０……
光源駆動回路、３１〜３５……トランジスタ、３
６〜３８……抵抗、３９……差動増幅回路、４０
……電源電圧の入力端子、４１……定電圧の入力
端子。
Fig. 1 is a circuit diagram showing an embodiment of a light source driving circuit according to the present invention, Fig. 2 is a block diagram showing an example of an optical information reading device using this embodiment, and Fig. 3 is a circuit diagram showing an example of an optical information reading device using this embodiment. A circuit diagram showing an example, and FIG. 4 is a graph diagram showing test results of changes in output voltage of a dry battery over time. 1 to 10...LED, 18...Light source, 30...
Light source drive circuit, 31-35...transistor, 3
6-38...Resistor, 39...Differential amplifier circuit, 40
...Input terminal for power supply voltage, 41...Input terminal for constant voltage.
Claims (1)
電源電圧を印加し、該発光素子を発光させるよう
にした光源駆動回路において、該発光素子夫々に
同一チツプ上に形成されたトランジスタを１つず
つ直列接続するとともに、該トランジスタ夫々に
流れる電流の合計電流が流れる抵抗と、該合計電
流による該抵抗の両端電圧と一定の基準電圧とを
比較する差動増幅回路とを設け、該差動増幅回路
の出力により、該抵抗の両端電圧と該基準電圧と
の差が一定となるように、該トランジスタを全て
制御することを特徴とする光源駆動回路。 In a light source drive circuit in which a DC power supply voltage is commonly applied to a plurality of light emitting elements forming a light source to cause the light emitting elements to emit light, one transistor formed on the same chip is connected to each of the light emitting elements. A resistor connected in series and through which a total current of the currents flowing through each of the transistors flows, and a differential amplifier circuit that compares a voltage across the resistor due to the total current with a constant reference voltage, the differential amplifier circuit 1. A light source driving circuit, wherein all of the transistors are controlled by the output of the transistor so that the difference between the voltage across the resistor and the reference voltage is constant.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1830890U JPH0751638Y2 (en) | 1990-02-27 | 1990-02-27 | Light source drive circuit |
| US07/653,191 US5144117A (en) | 1990-02-27 | 1991-02-07 | Illumination type optical recorded information reading device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1830890U JPH0751638Y2 (en) | 1990-02-27 | 1990-02-27 | Light source drive circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03110562U true JPH03110562U (en) | 1991-11-13 |
| JPH0751638Y2 JPH0751638Y2 (en) | 1995-11-22 |
Family
ID=31521471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1830890U Expired - Lifetime JPH0751638Y2 (en) | 1990-02-27 | 1990-02-27 | Light source drive circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0751638Y2 (en) |
-
1990
- 1990-02-27 JP JP1830890U patent/JPH0751638Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0751638Y2 (en) | 1995-11-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |