CN-116125331-B - Device and method for detecting load short circuit and open circuit of loudspeaker on line based on D-type power amplifier

CN116125331BCN 116125331 BCN116125331 BCN 116125331BCN-116125331-B

Abstract

The invention discloses a device and a method for detecting a load short circuit open circuit on line of a loudspeaker based on a class D power amplifier, wherein the detection device comprises a current acquisition module, a current prediction module, a comparator and a fault judgment module, the input end of the comparator is used for comparing the collected upper tube current and lower tube current with the predicted current I EXPECT after the offset is overlapped. The invention compares the collected upper tube current and lower tube current with the predicted current through the comparator, judges the result by the fault judging module and sends out corresponding feedback signals. The detection scheme can not interfere the sound frequency spectrum played by the loudspeaker, and the detection device can be used for rapidly and effectively detecting, and is high in efficiency and low in cost.

Inventors

LIU SHIZHOU
DING SHUANGXI
CAO HUA
WANG XIUYUAN

Assignees

苏州至盛半导体科技有限公司

Dates

Publication Date: 20260505
Application Date: 20221208

Claims (4)

1. The loudspeaker load short-circuit open-circuit on-line detection device based on the class D power amplifier is characterized by comprising a current acquisition module, a current prediction module, a comparator and a fault judgment module, The current acquisition module is used for acquiring and recording the currents of the upper pipe and the lower pipe; The current prediction module is used for predicting the superposition offset of the current I EXPECT according to the input audio signal, the gain of the power amplification system and the impedance of the loudspeaker; the current prediction module comprises a band-pass filter, a first multiplier, a second multiplier, a first divider, a second divider, a first adder and a second adder; the input end of the first divider is electrically connected with the output end of the first multiplier and is used for dividing the audio signal in the set frequency range f L -f H after gain by the maximum impedance of the frequency range loudspeaker to form a first offset, the input end of the second divider is electrically connected with the output end of the second multiplier and is used for dividing the audio signal in the set frequency range f L -f H after gain by the minimum impedance of the frequency range loudspeaker to form a second offset, and the input ends of the first adder and the second adder are respectively electrically connected with the output ends of the first divider and the second divider and are used for respectively superposing the first offset and the second offset on the predicted current I EXPECT ; the input end of the comparator is electrically connected with the output ends of the current acquisition module and the current prediction module, and the comparator respectively compares the acquired upper tube current and lower tube current with the predicted current I EXPECT after the offset is overlapped; The input end of the fault judging module is electrically connected with the output end of the comparator and is used for judging whether the loudspeaker load has open-circuit faults and short-circuit faults or not according to the comparison result of the comparator and sending out corresponding feedback signals.
2. The class D power amplifier-based speaker open load short circuit on-line detection device of claim 1, wherein the fault decision module comprises an open load detection module configured to: S11, regarding the upper tube current and the lower tube current of the audio D-type power amplifier, if the current is always larger than the predicted current I EXPECT after the first offset is overlapped in the set counting period 1/f L , no open circuit fault occurs in the loudspeaker load; S12, regarding the upper tube current and the lower tube current of the audio D type power amplifier, if the predicted current I EXPECT is always smaller than the predicted current I EXPECT after the first offset is superimposed within the set counting period 1/f L and the predicted current I EXPECT is larger than the set threshold I THR , the open-circuit fault of the loudspeaker occurs, the open-circuit alarm of the loudspeaker is reported, and if the predicted current I EXPECT is always smaller than the predicted current I EXPECT after the first offset is superimposed within the set counting period 1/f L and the predicted current I EXPECT does not exceed the set threshold I THR , the detection result is judged to be invalid.
3. The class D power amplifier-based speaker load short-circuit open-circuit on-line detection device of claim 1, wherein the fault determination module further comprises a load short-circuit detection module configured to: s21, regarding the upper tube current and the lower tube current of the audio D-type power amplifier, if the current is always smaller than the predicted current I EXPECT after the second offset is overlapped in the set counting period 1/f L , no short-circuit fault occurs to the loudspeaker load; S22, regarding the upper tube current and the lower tube current of the audio D type power amplifier, if the predicted current I EXPECT is always larger than the predicted current I THR after the second offset is superimposed within the set counting period 1/f L , and the predicted current I EXPECT is larger than the set threshold I THR , the speaker is loaded with a short-circuit fault, and the speaker short-circuit alarm is reported, and if the predicted current I EXPECT is always larger than the predicted current I EXPECT after the second offset is superimposed within the set counting period 1/f L , and the predicted current I EXPECT does not exceed the set threshold I THR , the detection result is judged to be invalid.
4. The method for detecting the open circuit of the load of the loudspeaker based on the class D power amplifier is characterized by being applied to the device for detecting the open circuit of the load of the loudspeaker based on the class D power amplifier according to the claim 1, and comprises the following steps: S1, detecting a load open circuit of a loudspeaker, namely sampling the current of an OUTP and an OUTN upper tube and the current of an OUTP and an OUTN lower tube of an audio D power amplifier in each PWM period, if the current of the upper tube and the current of the lower tube of the audio D power amplifier in a certain counting period 1/f L are always smaller than a predicted current I EXPECT after a first offset is overlapped, and the predicted current I EXPECT is larger than a set threshold I THR , judging that the detection result is effective, and reporting an open circuit alarm of the loudspeaker; S2, detecting a speaker load short circuit, namely sampling the current of the OUTP and OUTN upper tube currents and the OUTP and OUTN lower tube currents of the audio D power amplifier in each PWM period, and if the current of the OUTP and the OUTN upper tube currents and the lower tube currents of the audio D power amplifier in a certain counting period 1/f L are always larger than a predicted current I EXPECT after a second offset is overlapped, and the predicted current I EXPECT is larger than a set threshold I THR , judging that the detection result is effective, and reporting a speaker short circuit alarm.

Description

Device and method for detecting load short circuit and open circuit of loudspeaker on line based on D-type power amplifier Technical Field The invention belongs to the technical field of speakers, and particularly relates to a speaker load short-circuit open-circuit on-line detection device and method based on a class D power amplifier. Background Electric vehicles are being accelerated and popularized, and people pay more attention to driving comfort and safety. Vehicle audio systems are taking a fully upgraded fast lane as a key component affecting the ride experience. The number of speakers is increased from 4 to 8-24 at present, and in addition, as the number of motors in the electric vehicle is increased and the complexity of various heat management systems and battery management systems is improved, the number of wire harnesses in the vehicle is increased, and various wire harnesses are interwoven together, so that higher requirements are put on reliability. The wiring of the loudspeaker is longer in the vehicle body, the standard vehicle-mounted sound system generally detects the state of the loudspeaker before starting up, the traditional detection method mainly carries out diagnosis on the state of the loudspeaker before starting up, but the state of the loudspeaker after the sound system is started up and works cannot be diagnosed in real time, failure alarm cannot be actively carried out in the driving process, the safety is affected, and particularly, the vehicle-mounted sound system is used for rescue interaction scenes. The detection of the speaker short circuit and open circuit is essentially to inject a specific voltage to the speaker load through the audio power amplifier, then detect the corresponding current (or inject a certain current to detect the voltage at both sides of the speaker), and judge the impedance of the current speaker according to the relation between the voltage and the current. In either method (voltage injection or current injection), a core problem is that a test signal of a specific frequency is required to be provided, and the test signal cannot interfere with the played sound spectrum (sound content) of the speaker or fall within the designed sound frequency band of the speaker. Therefore, a device and a method for detecting the open circuit of the load of the speaker based on the class D power amplifier are needed to be proposed. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a device and a method for detecting a load short circuit open circuit on line of a loudspeaker based on a class D power amplifier. In order to solve the technical problems, the invention provides the following technical scheme: the invention provides a class-D power amplifier-based loudspeaker load short-circuit open-circuit on-line detection device, which comprises a current acquisition module, a current prediction module, a comparator and a fault judgment module, The current acquisition module is used for acquiring and recording the currents of the upper pipe and the lower pipe; The current prediction module is used for predicting the superposition offset of the current I EXPECT according to the input audio signal, the gain of the power amplification system and the impedance of the loudspeaker; the input end of the comparator is electrically connected with the output ends of the current acquisition module and the current prediction module and is used for comparing the acquired upper tube current and lower tube current with the predicted current I EXPECT after the offset is overlapped; The input end of the fault judging module is electrically connected with the output end of the comparator and is used for judging whether the loudspeaker load has open-circuit faults and short-circuit faults according to the comparison result of the comparator and the magnitude of the current predicted current value, and sending out corresponding feedback signals. Preferably, the current prediction module comprises a band-pass filter, a first multiplier, a second multiplier, a first divider, a second divider, a first adder and a second adder; The input end of the band-pass filter is electrically connected to the audio signal of the audio D-type power amplifier and is used for acquiring the audio signal in the set frequency band range f L-fH; The input ends of the first multiplier and the second multiplier are electrically connected with the output end of the band-pass filter and are used for multiplying the audio signal in the set frequency band range f L-fH with the amplifying gain G of the power amplifier; The input end of the first divider is electrically connected with the output end of the first multiplier and is used for dividing the audio signal in the set frequency band range f L-fH after gain by the maximum impedance of the frequency band loudspeaker to form a first offset; the input end of the second divider is electrically connected with the output