JPH0670444A - Overcurrent protection network - Google Patents
Overcurrent protection networkInfo
- Publication number
- JPH0670444A JPH0670444A JP24011892A JP24011892A JPH0670444A JP H0670444 A JPH0670444 A JP H0670444A JP 24011892 A JP24011892 A JP 24011892A JP 24011892 A JP24011892 A JP 24011892A JP H0670444 A JPH0670444 A JP H0670444A
- Authority
- JP
- Japan
- Prior art keywords
- jack
- resistance
- switching element
- fet2
- overcurrent
- 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
Abstract
Description
【０００１】[0001]
【産業上の利用分野】無線通信機における表示器付スピ
ーカマイクロホン等への電源送出用の電源保護回路に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power protection circuit for sending power to a speaker microphone with a display in a wireless communication device.
【０００２】[0002]
【従来の技術】無線通信機の据置形、車載形では本体に
ケーブル付マイクロホンのプラグを挿入して通話を行う
のが普通であるが、この方式のマイクロホンケース内に
スピーカを加えたものや、更に、周波数表示用の表示器
を組込んだものもあり、その外に、電源スイッチ、周波
数及びモード設定等のリモート機能を付加したものも実
用化されている。しかも、現在ではハンディタイプの無
線通信機にもこの表示器付リモコンスピーカマイクロホ
ンが常識となりつつある。2. Description of the Related Art In the stationary type and in-vehicle type of a wireless communication device, it is common to insert a plug of a microphone with a cable into the main body to make a call, but a system in which a speaker is added in a microphone case of this system, Further, there is one that incorporates a display for frequency display, and one that has a remote function such as a power switch and frequency and mode setting in addition to that has been put into practical use. Moreover, nowadays, the remote control speaker microphone with a display is becoming a common sense in handy type wireless communication devices.
【０００３】図３は無線通信機とスピーカマイクロホン
の接続図である。図３の７は無線通信機本体、８はスピ
ーカマイクロホン用ケース、９は接続ケーブルである。
通常はジャック・プラグを使う関係で多芯線ケーブルに
よる接続ではなく、スピーカ用ケーブルと、マイクロホ
ン用ケーブルに分けて接続している。その場合スピーカ
用ケーブルにはスピーカ用信号及びデータ信号の送受用
とし、マイクロホン用ケーブルは送信用のＰＴＴスイッ
チ・マイクロホン信号及び表示器等に供給する電源が送
られる。接続にプラグ・ジャックを用いる事で無線通信
機から送出する電源がプラグの着脱時に基準電位にショ
ートする場合がある。又、その他、表示器付スピーカマ
イクロホン用ケース内で故障が発生して過電流が流れる
場合もあるが、そのために表示器付スピーカマイクロホ
ン用ケースへの電源供給には特別の保護回路は設けられ
てなかった。FIG. 3 is a connection diagram of a wireless communication device and a speaker microphone. In FIG. 3, reference numeral 7 is a main body of the wireless communication device, 8 is a case for a speaker microphone, and 9 is a connection cable.
Normally, because of the use of jacks and plugs, they are not connected by a multi-core cable, but by connecting them to a speaker cable and a microphone cable. In that case, the speaker cable is used for transmitting and receiving a speaker signal and a data signal, and the microphone cable is supplied with power for supplying to a PTT switch / microphone signal for transmission and a display. When a plug / jack is used for connection, the power supplied from the wireless communication device may short-circuit to the reference potential when the plug is attached / detached. In addition, in some cases, a fault may occur in the speaker / microphone case with a display and an overcurrent may flow. Therefore, a special protection circuit is provided for supplying power to the speaker / microphone case with a display. There wasn't.
【０００４】[0004]
【発明が解決しようとする課題】本発明は上述したよう
な無線通信機本体のジャックとプラグを介して接続され
る表示器付スピーカマイクロホン用ケースに供給する電
源線路が基準電位にショートしたり、負荷側の故障等で
発生する定格電流を超える過電流が流れた場合に対処す
る電源用の保護回路の提供を目的とする。SUMMARY OF THE INVENTION According to the present invention, a power supply line supplied to a case for a speaker / microphone with a display connected to a jack and a plug of a wireless communication device body as described above is short-circuited to a reference potential, An object of the present invention is to provide a protection circuit for a power supply, which copes with an overcurrent that exceeds the rated current generated due to a failure on the load side.
【０００５】[0005]
【課題を解決するための手段】無線通信機の電源回路
と、外部負荷とを接続するジャック端子との間に抵抗と
半導体のスイッチング素子を直列に接続する。この抵抗
とスイッチング素子で生じる電圧降下を正常な定格電流
と負荷異常による過電流状態が判断できるように抵抗と
スイッチング素子からなる回路に並列に接続した抵抗に
より電圧降下を検出し、その検出値で過電流による電圧
降下があると制御電圧をスイッチング素子に供給してス
イッチング素子をオフにして電源の供給を遮断する構成
である。A resistor and a semiconductor switching element are connected in series between a power supply circuit of a wireless communication device and a jack terminal for connecting an external load. The voltage drop caused by this resistance and the switching element is detected by the resistance connected in parallel with the circuit consisting of the resistance and the switching element so that the normal rated current and the overcurrent state due to the load abnormality can be judged. When there is a voltage drop due to an overcurrent, the control voltage is supplied to the switching element to turn off the switching element to cut off the power supply.
【０００６】[0006]
【作用】抵抗と半導体のスイッチング素子について、負
荷の正常な定格電流を１００ｍＡとし、抵抗とスイッチ
ング素子の直列抵抗値を１０Ωとすればこの間の消費電
力は０．１Ｗとなる。またこの時の電圧降下は約１Ｖで
ある。負荷側の異常による過電流を２５０ｍＡとすれば
電圧降下は約２．５Ｖとなる。この電圧降下の差によっ
てスイッチング素子をオン・オフすればよい。そこでＰ
ＮＰトランジスタを制御素子とし、０．６Ｖのベースバ
イアスでオン動作になるとすれば検出した電圧降下を１
／５程度に分割してベースバイアスとすることでスイッ
チングの動作点が設定できる。この、ＰＮＰトランジス
タのオン動作でスイッチング素子をオフになるよう構成
すればよい。With respect to the resistance and the switching element of the semiconductor, if the normal rated current of the load is 100 mA and the series resistance value of the resistance and the switching element is 10Ω, the power consumption during this period is 0.1 W. The voltage drop at this time is about 1V. If the overcurrent due to the abnormality on the load side is 250 mA, the voltage drop will be about 2.5V. The switching element may be turned on / off depending on the difference in the voltage drop. So P
If the NP transistor is used as a control element and the ON operation is performed with a base bias of 0.6 V, the detected voltage drop is 1
The operating point of switching can be set by dividing into about / 5 to use as the base bias. The switching element may be turned off by the ON operation of the PNP transistor.
【０００７】[0007]
【実施例】図１は本発明の過電流保護回路の一実施例を
示す回路図である。図面にもとづいて詳細に説明する。
図中１は本発明の過電流保護回路である。この過電流保
護回路は電源を接続端子４の（＋）Ｂ電源端子を介して
抵抗Ｒ1に接続し、抵抗Ｒ1からＦＥＴ２のソース端子に
接続し、ＦＥＴ２のドレーンからマイクロホン用ジャッ
ク５の電源端子に接続し、更に不図示の表示器付マイク
ロホンスピーカのプラグの電源端子（以下外部負荷と記
す）へと接続する。このＦＥＴ２のゲートは抵抗Ｒ2で
基準電位に接続されている。接続端子４の（＋）Ｂ電源
端子から別に抵抗Ｒ3とＰＮＰトランジスタ３のエミッ
タが接続されており、抵抗Ｒ3の他の側はＰＮＰトラン
ジスタのベースと抵抗Ｒ4に接続し、抵抗Ｒ4の他方はＦ
ＥＴ２のドレーンに接続してある。ＰＮＰトランジスタ
３のコレクタはＦＥＴ２のゲートに接続されている。即
ち、抵抗Ｒ1とＦＥＴ２からなる電圧降下機能を備えた
スイッチング回路と、抵抗Ｒ3と抵抗Ｒ4によるベースバ
イアスでスイッチング素子の制御信号を出力する回路と
で構成される。図１にはその他に無線通信機本体からの
接続端子４から表示器付スピーカマイクロホン用のスピ
ーカ線路、データ線路、マイクロホン及びＰＴＴスイッ
チ用線路がスピーカ用ジャック５とマイクロホン用ジャ
ック６に接続されているが、本発明と直接関係がないの
で説明は省略する。FIG. 1 is a circuit diagram showing an embodiment of an overcurrent protection circuit of the present invention. It will be described in detail with reference to the drawings.
In the figure, reference numeral 1 is an overcurrent protection circuit of the present invention. This overcurrent protection circuit connects the power source to the resistor R 1 via the (+) B power source terminal of the connection terminal 4, connects the resistor R 1 to the source terminal of the FET 2, and connects the drain of the FET 2 to the power source of the microphone jack 5. Connect to the power supply terminal (hereinafter referred to as an external load) of the plug of the microphone speaker with a display (not shown). The gate of the FET2 is connected to a reference potential by resistor R 2. The resistor R 3 and the emitter of the PNP transistor 3 are separately connected from the (+) B power supply terminal of the connection terminal 4, and the other side of the resistor R 3 is connected to the base of the PNP transistor and the resistor R 4 , and the resistor R 4 The other is F
It is connected to the drain of ET2. The collector of the PNP transistor 3 is connected to the gate of the FET 2. That is, it is composed of a switching circuit having a voltage drop function, which is composed of the resistor R 1 and the FET 2, and a circuit which outputs a control signal of the switching element by the base bias of the resistors R 3 and R 4 . In FIG. 1, in addition, a speaker line for a speaker with display microphone, a data line, a line for microphone and PTT switch are connected to a speaker jack 5 and a microphone jack 6 from a connection terminal 4 from the main body of the wireless communication device. However, the description is omitted because it is not directly related to the present invention.
【０００８】この過電流保護回路の実施例について数値
を入れて説明する。実施例の回路では抵抗Ｒ1を４．７
Ω抵抗Ｒ2を１００ＫΩ抵抗Ｒ3を４７ＫΩ抵抗Ｒ4を１
５０ＫΩに設定する。ここで外部負荷が正常であれば、
ＦＥＴ２のゲートは抵抗１００ＫΩで基準電位であるの
でゲート・ソース間の電圧ＶGSは最大値であり、従って
ＦＥＴ２はオン動作となって、ＦＥＴ２ソースからドレ
ーンに、ドレーンから外部負荷に電源が供給される。Ｆ
ＥＴ２の内部抵抗ＲDSは約５Ωである。外部負荷が正常
の場合定格電流を１００ｍＡとすると電圧降下用の抵抗
値は、Ｒ1（４．７Ω）＋ＲDS（５．０Ω）＝９．７Ω
となり、約１Ｖの電圧降下となる。この電圧でＰＮＰト
ランジスタ３がオフであるように抵抗Ｒ3が４７ＫΩ、
抵抗Ｒ4を１５０ＫΩとしてあるので、ベースエミッタ
間の電圧は約０．２ＶでＰＮＰトランジスタはオフ状態
を保持し、ＦＥＴ２のオン動作は保持される。An embodiment of this overcurrent protection circuit will be described by including numerical values. In the circuit of the embodiment, the resistance R 1 is 4.7.
Ω resistor R 2 is 100KΩ resistor R 3 is 47KΩ resistor R 4 is 1
Set to 50KΩ. If the external load is normal here,
Since the gate of the FET2 has a resistance of 100 KΩ and the reference potential, the voltage V GS between the gate and the source is the maximum value, and therefore the FET2 is turned on and power is supplied from the FET2 source to the drain and from the drain to an external load. It F
The internal resistance R DS of ET2 is about 5Ω. When the external load is normal and the rated current is 100 mA, the resistance for voltage drop is R 1 (4.7Ω) + R DS (5.0Ω) = 9.7Ω
And the voltage drop is about 1V. The resistance R 3 is 47 KΩ so that the PNP transistor 3 is turned off at this voltage,
Since the resistance R 4 is set to 150 KΩ, the voltage between the base and the emitter is about 0.2 V, the PNP transistor is kept in the OFF state, and the ON operation of the FET 2 is kept.
【０００９】次に外部負荷に異常が発生し過電流が流れ
たとするその過電流を２５０ｍＡとすると、抵抗Ｒ1と
ＦＥＴ２の内部抵抗ＲDSによる電圧降下は約２．５Ｖと
なる。この電圧降下２．５ＶとなるとＰＮＰトランジス
タ３のベースエミッタ間の電圧が約０．６Ｖとなって、
ＰＮＰトランジスタ３はオン動作となる。このようにＰ
ＮＰトランジスタ３のオン・オフ用制御のベースバイア
ス電圧は抵抗Ｒ3と抵抗Ｒ4によって定める。その為過電
流の判定基準を決めればその判定に合わせた抵抗値を設
定すればよい。ＰＮＰトランジスタ３がオンとなるとＦ
ＥＴ２のゲートに正電圧を供給するのでＦＥＴ２はオフ
動作となって外部負荷の電源供給を遮断して電源回路は
保護される。図２はＦＥＴ２の動作電流を示す図である
が、上記のように過電流の判定基準を必要に応じて設定
変えすることでＦＥＴ２のオン・オフ動作点を設定値に
合った電流値に変更できる。Next, assuming that an overcurrent flows when an abnormality occurs in the external load and the overcurrent is 250 mA, the voltage drop due to the resistance R 1 and the internal resistance R DS of the FET 2 becomes about 2.5V. When this voltage drop becomes 2.5V, the voltage between the base and emitter of the PNP transistor 3 becomes about 0.6V,
The PNP transistor 3 is turned on. Thus P
The base bias voltage for on / off control of the NP transistor 3 is determined by the resistors R 3 and R 4. Therefore, if the criterion for determining the overcurrent is determined, the resistance value may be set according to the determination. When the PNP transistor 3 is turned on, F
Since a positive voltage is supplied to the gate of ET2, FET2 is turned off and the power supply to the external load is cut off to protect the power supply circuit. FIG. 2 is a diagram showing the operating current of the FET2. By changing the setting criteria for the overcurrent as described above, the on / off operating point of the FET2 is changed to a current value that matches the set value. it can.
【００１０】ＰＮＰトランジスタ３がオンとなると、そ
れ以降は抵抗Ｒ3と抵抗Ｒ4と外部負荷の抵抗によってＰ
ＮＰトランジスタ３がオン動作を保持する。この電源供
給の遮断状態を解除するためには外部負荷のプラグを引
き抜く事によって解除される。When the PNP transistor 3 is turned on, P is turned on by the resistors R 3 and R 4 and the resistance of the external load thereafter.
The NP transistor 3 holds the ON operation. In order to cancel the power supply cutoff state, the plug of the external load is pulled out.
【００１１】この発明については実施例でＦＥＴとＰＮ
Ｐトランジスタの組合せで述べてきたが、ＦＥＴの代り
に通常のトランジスタを用いる事も、ＰＮＰトランジス
タをＮＰＮ型で構成する事も可能であり、電圧降下の設
定と、設定した電圧を超える電圧降下があると電源供給
回路のスイッチング素子に遮断制御信号を出して電源の
供給を遮断するものである。In the embodiment of the present invention, an FET and a PN are used.
Although it has been described with the combination of P transistors, it is possible to use a normal transistor instead of the FET or to configure the PNP transistor with an NPN type, and the voltage drop setting and the voltage drop exceeding the set voltage may occur. In this case, a cutoff control signal is output to the switching element of the power supply circuit to cut off the power supply.
【００１２】[0012]
【発明の効果】本発明による抵抗と半導体のスイッチン
グ素子の内部抵抗による電圧降下を用いて、電源供給の
接断の制御信号を生成してスイッチング素子に印加し
て、負荷側の異常による過電流で生じた電圧降下ではス
イッチング素子を遮断させるので電源回路を保護する実
用上の効果がある。By using the voltage drop due to the resistance according to the present invention and the internal resistance of the semiconductor switching element, a control signal for disconnecting the power supply is generated and applied to the switching element, and an overcurrent due to an abnormality on the load side is generated. Since the switching element is cut off by the voltage drop generated at 2, there is a practical effect of protecting the power supply circuit.
【図１】本発明の一実施例を示す過電流保護回路の回路
図である。FIG. 1 is a circuit diagram of an overcurrent protection circuit showing an embodiment of the present invention.
【図２】図１に示す回路図の電流による動作特性図であ
る。2 is an operating characteristic diagram according to current in the circuit diagram shown in FIG. 1. FIG.
【図３】無線通信機と表示付スピーカマイクロホンの構
成図である。FIG. 3 is a configuration diagram of a wireless communication device and a speaker microphone with a display.
【符号の説明】１ 過電流保護回路 ２ ＦＥＴ ３ ＰＮＰトランジスタ ４ 端子 ５ スピーカ用ジャック ６ マイクロホン用ジャック ７ 無線通信機 ８ 表示器付スピーカマイクロホン ９ ケーブル Ｒ1,Ｒ2,Ｒ3,Ｒ4 抵抗[Description of symbols] 1 overcurrent protection circuit 2 FET 3 PNP transistor 4 terminal 5 speaker jack 6 microphone jack 7 wireless communication device 8 speaker microphone with display 9 cable R 1 , R 2 , R 3 , R 4 resistance
Claims (1)
ッチング素子とを直列に接続し、該抵抗とスイッチング
素子による電圧降下が所定のレベルを超えると、スイッ
チング素子をオフにして電源供給を遮断するよう構成し
た過電流保護回路。1. A resistor and a semiconductor switching element are connected in series between a power source and a load, and when the voltage drop due to the resistor and the switching element exceeds a predetermined level, the switching element is turned off to supply power. Overcurrent protection circuit configured to shut off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24011892A JPH0670444A (en) | 1992-08-18 | 1992-08-18 | Overcurrent protection network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24011892A JPH0670444A (en) | 1992-08-18 | 1992-08-18 | Overcurrent protection network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0670444A true JPH0670444A (en) | 1994-03-11 |
Family
ID=17054761
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24011892A Pending JPH0670444A (en) | 1992-08-18 | 1992-08-18 | Overcurrent protection network |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0670444A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034705B2 (en) | 2000-08-04 | 2006-04-25 | Matsushita Electric Industrial Co., Ltd. | Emergency information terminal and emergency information system including terminal |
| US7643263B2 (en) * | 2007-08-08 | 2010-01-05 | Motorola, Inc. | Controlling over-current from a power supply to a device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0525945B2 (en) * | 1986-06-03 | 1993-04-14 | Kobe Steel Ltd |
-
1992
- 1992-08-18 JP JP24011892A patent/JPH0670444A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0525945B2 (en) * | 1986-06-03 | 1993-04-14 | Kobe Steel Ltd |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7034705B2 (en) | 2000-08-04 | 2006-04-25 | Matsushita Electric Industrial Co., Ltd. | Emergency information terminal and emergency information system including terminal |
| US7088225B2 (en) | 2000-08-04 | 2006-08-08 | Matsushita Electric Industrial Co., Ltd. | Emergency information terminal and emergency information system including terminal |
| US7643263B2 (en) * | 2007-08-08 | 2010-01-05 | Motorola, Inc. | Controlling over-current from a power supply to a device |
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