CN202143206U

CN202143206U - Speaker detection circuit

Info

Publication number: CN202143206U
Application number: CN201120255047U
Authority: CN
Inventors: 舒彩云; 王凯; 尹玉涛; 李梦婵; 王盟; 薛守博; 苗天凤; 宋云龙; 苗璐; 陈平
Original assignee: JIANGSU TOPPOWER AUTOMOTIVE ELECTRONICS CO Ltd
Current assignee: JIANGSU TOPPOWER AUTOMOTIVE ELECTRONICS CO Ltd
Priority date: 2011-07-19
Filing date: 2011-07-19
Publication date: 2012-02-08
Anticipated expiration: 2021-07-19

Abstract

The utility model discloses a speaker detection circuit, which relates to the technical field of speaker detection. A detection circuit is connected between a power amplifier TDA 7388A and a single chip, the detection circuit comprises five transistors, and base electrodes of the first transistor and the fifth transistor are connected with the single chip to serve as a signal input end; the collector of the first transistor is connected with the pin4 of the power amplifier TDA7388A, and the emitter of the first transistor is connected with the base electrode of the second transistor; the collector of the second transistor is taken as a signal detection end and is connected with the single chip; the collector of the fifth transistor is connected with the pin24 of the power amplifier TDA7388A, and the emitter of the fifth transistor is connected with the base electrode of the third transistor; the collector of the third transistor is connected with the collector of the second transistor, and the emitter of the third transistor is grounded; and the base electrode of the fourth transistor is connected with the pin5 of the power amplifier TDA7388A, and the collector of the fourth transistor is respectively connected with the pin6 and the pin22 of the TDA7388A. The speaker detection circuit has the advantage that the number of the speakers on an automobile can be automatically identified.

Description

The loudspeaker testing circuit

Technical field

The utility model relates to loudspeaker detection technique field, specifically is a kind of loudspeaker testing circuit, is mainly used in the detection of automotive acoustic speaker.

Background technology

At present, along with the direction of automobile industry towards intelligence environment protection develops, the sound equipment that is installed in above the automobile is also constantly upgrading and upgrading.4 loudspeaker (front two with two of back) are all arranged and along with the generation of some compact economical-type automobiles in the general automobile; Only be equipped with two preceding loudspeaker in these cars, so just required automobile audio can discern two sound channels or quadrophonic output automatically, for example: the automobile that four loudspeaker are installed; Automobile audio is just exported four road audio frequency; And the automobile of two loudspeaker in front only has been installed, sound equipment also just requires corresponding output front two-way audio, but the intelligent power output amplification that this band loudspeaker detect on market than the power amplifier with measuring ability is not expensive one times; Consider that from the cost angle such intelligent power output amplification only limits to the sound equipment that is used for some high-end cars.

Summary of the invention

In order to overcome the shortcoming of above-mentioned prior art; The utility model provides a kind of loudspeaker testing circuit; Can discern what adorn above the automobile automatically is two loudspeaker or four loudspeaker; Thereby do corresponding audio frequency output transform, the comparatively simple cost of this circuit is also lower simultaneously, has realized the loudspeaker recognition function that only high-end power amplifier just possesses.

The utility model is realized with following technical scheme: a kind of loudspeaker testing circuit; Between power amplifier TDA7388A and single-chip microcomputer, connect a testing circuit, described testing circuit comprises the first transistor, transistor seconds, the 3rd transistor, the 4th transistor and the 5th transistor; The first transistor is connected as signal input part with single-chip microcomputer with the 5th transistorized base stage, and the collector electrode of the first transistor links to each other with 4 pin of power amplifier TDA7388A, and its emitter is connected with the base stage of transistor seconds; The collector electrode of transistor seconds is connected with single-chip microcomputer as the input end, and collector electrode also is connected its grounded emitter through a pull-up resistor with the 5V power supply; The 5th transistorized collector electrode links to each other with 24 pin of power amplifier TDA7388A, and its emitter is connected with the 3rd transistorized base stage; The 3rd transistorized collector electrode is connected with the collector electrode of transistor seconds, its grounded emitter; The 4th transistorized base stage is connected with 5 pin of power amplifier TDA7388A through a resistance, and its emitter connects the 3V power supply, and collector electrode is connected with 6,22 pin of power amplifier TDA7388A through diode respectively.

The beneficial effect of the utility model is: after increasing by a simple circuit on the common power amplifier, becoming becomes the intelligent power output amplification that the band loudspeaker detect, and satisfies the right function that loudspeaker are detected, and this circuit performance is stable and economical and practical.

Description of drawings

Below in conjunction with accompanying drawing the utility model is described further.

Accompanying drawing 1 is the utility model circuit diagram.

Embodiment

Shown in accompanying drawing; The loudspeaker testing circuit is between power amplifier TDA7388A and single-chip microcomputer, to connect a testing circuit, and described testing circuit comprises the first transistor Q1, transistor seconds Q002, the 3rd transistor Q082, the 4th transistor Q240 and the 5th transistor Q290; The base stage of the first transistor Q1 and the 5th transistor Q290 is connected as signal input part with single-chip microcomputer, and the collector electrode of the first transistor Q1 links to each other with 4 pin of power amplifier TDA7388A, and its emitter is connected with the base stage of transistor seconds Q002; The collector electrode of transistor seconds Q002 is connected with single-chip microcomputer as the input end, and collector electrode also is connected its grounded emitter through a pull-up resistor with the 5V power supply; The collector electrode of the 5th transistor Q290 links to each other with 24 pin of power amplifier TDA7388A, and its emitter is connected with the base stage of the 3rd transistor Q082; The collector electrode of the 3rd transistor Q082 is connected with the collector electrode of transistor seconds Q002, its grounded emitter; The base stage of the 4th transistor Q240 is connected with 5 pin of power amplifier TDA7388A through a resistance, and its emitter connects the 3V power supply, and collector electrode is connected with 6,22 pin of power amplifier TDA7388A through diode respectively.

The utility model be each road output of utilizing power amplifier loudspeaker have and situation about not having under; The output of power amplifier has corresponding resistance change to design, and 8PIN and 10PIN are one group of output of power amplifier TDA7388A, when not inserting loudspeaker; The resistance value of power amplifier output is 120 ohm; So the general resistance of the loudspeaker of installation onboard be 4 ohm when loudspeaker when inserting power amplifier, corresponding variation has taken place in the resistance value of power amplifier output, after loudspeaker insert; The resistance value at power amplifier two ends is 120x4/ (120+4)=3.87 ohm, and detailed process is following:

When machine carried out the loudspeaker diagnostic mode, SPEAK_EN was a high level, and/AMP_STANDBY is a low level; So D1, D408, the 4th transistor Q240; The first transistor Q1 and the 5th transistor Q290 conducting simultaneously; If interior car has only connect two preceding loudspeaker, and loudspeaker not, R1 and the voltage above the R6 do; VR1=VR6 [(3.3V-VD408-VCEQ290)/(20+20+120)] * 20; VR1 and VR6 voltage are about 0.3V; So the 3rd transistor Q082 and transistor seconds Q002 can not conductings; SPK_DET still is a high level, so MCU just knows that working as the front and back loudspeaker does not connect, and so just only exports front two-way loudspeaker.

After loudspeaker also connect after two; At R1 and the voltage above the R6 is R1=VR6 [(3.3V-VD408-VCEQ290)/(20+20+3.87)] * 20, and the voltage of VR1 and VR6 is about 1.2V, so the 3rd transistor Q082 and transistor seconds Q002 conducting; This moment, SPK_DET became low level; This moment, MCU was after detection SPK_DET is low level, just knew that the back loudspeaker connect, and No. four loudspeaker are exported simultaneously before and after will letting so.

Claims

1. loudspeaker testing circuit; It is characterized in that: between power amplifier TDA7388A and single-chip microcomputer, connect a testing circuit, described testing circuit comprises the first transistor (Q1), transistor seconds (Q002), the 3rd transistor (Q082), the 4th transistor (Q240) and the 5th transistor (Q290); The first transistor (Q1) is connected as signal input part with single-chip microcomputer with the base stage of the 5th transistor (Q290), and the collector electrode of the first transistor (Q1) links to each other with 4 pin of power amplifier TDA7388A, and its emitter is connected with the base stage of transistor seconds (Q002); The collector electrode of transistor seconds (Q002) is connected with single-chip microcomputer as the input end, and collector electrode also is connected its grounded emitter through a pull-up resistor with the 5V power supply; The collector electrode of the 5th transistor (Q290) links to each other with 24 pin of power amplifier TDA7388A, and its emitter is connected with the base stage of the 3rd transistor (Q082); The collector electrode of the 3rd transistor (Q082) is connected its grounded emitter with the collector electrode of transistor seconds (Q002); The base stage of the 4th transistor (Q240) is connected with 5 pin of power amplifier TDA7388A through a resistance, and its emitter connects the 3V power supply, and collector electrode is connected with 6,22 pin of power amplifier TDA7388A through diode respectively.