Vehicle loudspeaker working state detection circuit and method

Abstract

The present invention discloses a vehicle loudspeaker working state detection circuit and method. According to vehicle loudspeaker impedance characteristics, when an OTL power amplifier output is connected with a loudspeaker, the direct current impedances of two ends of an LABA+ and an LABA- (which are earthed by default) are about 4 Ohm or 8 Ohm; when the loudspeaker is short circuit, the directcurrent impedances of two ends of the LABA+ and the LABA- are 0; when the OTL power amplifier output is not connected with the loudspeaker, the loudspeaker is equivalent to an open circuit and a suspension state; based on the impedance change of the two ends of the LABA+ and the LABA-, it is determined whether the vehicle loudspeaker is in the open-circuit or short-circuit state or not according to the jumping of the level of a second input end GPIO0 of an MCU processor and different voltage values collected by a first input end A/D of the MCU processor. The vehicle loudspeaker working state detection circuit and method can be applied to a device of a vehicle OTL audio amplifier and offline detection of one earthed end of the in-vehicle loudspeaker to check vehicle horn faults; and moreover, the vehicle loudspeaker working state detection circuit and method are low in cost and convenient to apply, can perform automatic detection for the vehicle sound player and can rapidly determine faults of the loudspeaker.

Description

technical field [0001] The invention relates to the technical field of loudspeaker fault detection, in particular to a circuit and method for detecting the working state of a vehicle-mounted loudspeaker. Background technique [0002] OTL audio power amplifiers are often used in car audio playback products, and the connection methods of OTL audio power amplifiers and speakers are different from those of OCL and BTL power amplifiers; The positive terminal of the speaker is connected to the signal output terminal of the power amplifier, and the negative terminal of the speaker is grounded. In practice, the output of the OTL audio power amplifier is often equipped with a combination of two or more car speakers. A loudspeaker is a transducer device that converts electrical signals into acoustic signals. According to its impedance characteristics, in the application of car audio equipment, the impedance of the speaker or the combined speaker is generally 4 ohms or 8 ohms. Durin...

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Problems solved by technology

During the production process of the car, the speaker and related wiring harness will be pre-buried and installed in a certain position of the car. For complex wiring, judge whether it is open or short circuit, unlike the speaker connected to the OCL and BTL power amplifiers (the speaker is bridge type) Connection method, one end is not grounded), you can use a fixed frequency waveform to scan and detect the speaker, and judge and calculate the existing impedance of the speaker through codec or level jump; and for the speaker with one end grounded, generally only artificial Use a multimeter to detect one by one. When there are multiple speakers at the output end of the OTL audio power amplifier, it is time-consuming and laborious to eliminate the open circuit and short circuit of the speakers through manual detection.

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