JPH02123147U

JPH02123147U -

Info

Publication number: JPH02123147U
Application number: JP3086989U
Authority: JP
Priority date: 1989-03-20
Filing date: 1989-03-20
Publication date: 1990-10-09
Anticipated expiration: 2004-03-20
Also published as: JPH071871Y2

Description

[Brief explanation of drawings]

第１図はこの考案の一実施例を示す接続図、第
２図は従来の回路を示す接続図。１……第１の定電流回路、２……第２の定電流
回路、３……第３の定電流回路、４……増幅用ト
ランジスタ、５……接続点、６……負荷抵抗、７
……増幅器、８，９……ダーリントン回路、１０
……出力点、１２……スピーカ、１３……第１の
スイツチングトランジスタ、１４……抵抗、１５
……キヤパシタ、１６……抵抗、１７……第２の
スイツチングトランジスタ、１９……電圧点。な
お、図中同一符号は同一または相当部分を示す。 FIG. 1 is a connection diagram showing an embodiment of this invention, and FIG. 2 is a connection diagram showing a conventional circuit. DESCRIPTION OF SYMBOLS 1... First constant current circuit, 2... Second constant current circuit, 3... Third constant current circuit, 4... Amplifying transistor, 5... Connection point, 6... Load resistor, 7
...Amplifier, 8,9...Darlington circuit, 10
... Output point, 12 ... Speaker, 13 ... First switching transistor, 14 ... Resistor, 15
... Capacitor, 16 ... Resistor, 17 ... Second switching transistor, 19 ... Voltage point. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims

[Claims for Utility Model Registration] A signal is input to the base of an amplifying transistor 4 whose emitter is connected to a power supply via a first constant current circuit 1 and whose collector is grounded via a second constant current circuit 2. , the output point 10 is connected to the power supply via the third constant current circuit 3, and the input base terminal of the Darlington circuit connected between the output point and the ground is connected to the terminal 5 on the collector side of the amplification transistor 4.
and a load resistor 6 between the terminals 5 and 10.
and connect the corresponding output point 10 of the above Darlington circuit.
In a semiconductor integrated circuit configured to connect a speaker circuit between the amplifying transistor 4 and the ground, a first switch whose collector is connected to the collector side terminal 5 of the amplifying transistor 4 and whose emitter is grounded via a resistor 14 is provided. a capacitor 1 connected in parallel to the resistor 14;
5 and a resistor 16 connected in series; a second switch whose collector is connected to a voltage point having almost the same potential as the terminal 5, and whose emitter side terminal is connected to the emitter of the first switching transistor 13; a switching transistor 17, means for controlling the second transistor 17 so that it is turned off while the first switching transistor 13 is turned on, and that the switching transistor 17 is turned on while the switching transistor 13 is turned off. semiconductor integrated circuits.