JPH01153724U - - Google Patents
Info
- Publication number
- JPH01153724U JPH01153724U JP5143988U JP5143988U JPH01153724U JP H01153724 U JPH01153724 U JP H01153724U JP 5143988 U JP5143988 U JP 5143988U JP 5143988 U JP5143988 U JP 5143988U JP H01153724 U JPH01153724 U JP H01153724U
- Authority
- JP
- Japan
- Prior art keywords
- transistor
- protection circuit
- drive transistor
- power amplifier
- short
- 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
- 230000006378 damage Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 2
Landscapes
- Amplifiers (AREA)
Description
第１図は、本考案の一実施例を示す回路図、及
び第２図は従来のパワーアンプを示す回路図であ
る。
３……駆駆トランジスタ、４，６……出力トラ
ンジスタ、１０，１１，１２……定電流トランジ
スタ、２０……短絡トランジスタ、２１……抵抗
。
FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional power amplifier. 3... Drive transistor, 4, 6... Output transistor, 10, 11, 12... Constant current transistor, 20... Short circuit transistor, 21... Resistor.
Claims (1)
を有するパワーアンプを破壊から保護する為の保
護回路であつて、正側出力トランジスタを駆動す
る駆動トランジスタと、該駆動トランジスタに動
作電流を供給する定電流トランジスタと、前記駆
動トランジスタのベースと前記定電流トランジス
タのコレクタとの間に接続された抵抗と、電源ラ
インに混入する大振幅のサージ電圧を検出し、前
記駆動トランジスタのベースを接地する保護回路
部とから成り、前記サージ電圧に対して出力トラ
ンジスタ及び定電流トランジスタを同時に保護す
る様にしたことを特徴とするパワーアンプの保護
回路。 (2) 前記保護回路部は、ツエナーダイオードか
ら得られる基準電圧と、電源電圧を分圧して得ら
れる電圧とを比較する比較手段と、該比較手段の
出力信号に応じてオンする短絡トランジスタとを
備え、該短絡トランジスタにより駆動トランジス
タのベースをアースに短絡する様にしたことを特
徴とする請求項第１項記載のパワーアンプの保護
回路。[Claims for Utility Model Registration] (1) A protection circuit for protecting a power amplifier having a push-pull connected output transistor from destruction, which includes a drive transistor that drives a positive output transistor, and a drive transistor that operates on the drive transistor. A constant current transistor that supplies current, a resistor connected between the base of the drive transistor and the collector of the constant current transistor, and a resistor that detects a large-amplitude surge voltage mixed into the power supply line and connects the base of the drive transistor. A protection circuit for a power amplifier, comprising a protection circuit section for grounding the power amplifier, and simultaneously protecting an output transistor and a constant current transistor against the surge voltage. (2) The protection circuit section includes a comparison means for comparing a reference voltage obtained from a Zener diode and a voltage obtained by dividing a power supply voltage, and a short-circuit transistor that is turned on in response to an output signal of the comparison means. 2. A protection circuit for a power amplifier according to claim 1, further comprising: a short-circuiting transistor which short-circuits the base of the drive transistor to ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1988051439U JPH0635536Y2 (en) | 1988-04-15 | 1988-04-15 | Power amplifier protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1988051439U JPH0635536Y2 (en) | 1988-04-15 | 1988-04-15 | Power amplifier protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01153724U true JPH01153724U (en) | 1989-10-23 |
| JPH0635536Y2 JPH0635536Y2 (en) | 1994-09-14 |
Family
ID=31277462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1988051439U Expired - Lifetime JPH0635536Y2 (en) | 1988-04-15 | 1988-04-15 | Power amplifier protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0635536Y2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60152108A (en) * | 1984-01-20 | 1985-08-10 | Hitachi Ltd | Amplifier circuit |
-
1988
- 1988-04-15 JP JP1988051439U patent/JPH0635536Y2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60152108A (en) * | 1984-01-20 | 1985-08-10 | Hitachi Ltd | Amplifier circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0635536Y2 (en) | 1994-09-14 |
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