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This lesson talks about the related circuits of the speakers of the HiSilicon platform

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In the circuit of this speaker, let's take a look at the components

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The one on the right is J3701

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The speaker is connected to the socket J3701 through a flat cable

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This is a small audio, usually called an audio power amplifier, also called a ringtone amplifier chip

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Its English is mostly SMARTPA on Android phones, and PA is the power amplifier

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This speaker is primarily driven by a small audio

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Look at the main audio chip

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The main audio chip is also called big audio, it is identified as CODEC or CDC in the drawings

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The CPU is a main chip that converts and controls these sound signals

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The main components related to the sound circuit in this circuit are these four components

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How does the speaker make sound?

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For example, if we want to play music, the CPU controls the program,

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and transmits the Internet data to the main audio through the bus

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The main audio decodes the sound signal,

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and finally gives the small audio through the I2S bus

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This I2S bus belongs to a digital signal, and this digital signal is a source of sound

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Then small audio internal conversion from digital to analog circuit, and then power amplification

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After the power is amplified, the sound signal is output to drive the speaker connected to the seat

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In this way, the speaker can produce sound when there is no problem with itself

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This is the general flow of how it works

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In this circuit, we can know that there are four

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When we check the line, we also start from the speaker,

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and then look for the line from the speaker seat to the small audio

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This is a frame diagram

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In fact, there are not only these two signals on the circuit from the small audio to the speaker,

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but also the detection signal

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Small audio also has its own working conditions,

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including power supply, clock, reset, boost circuit, and bus circuit

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The bus is just a transmission channel for sound signals

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The power amplifier needs to perform a series of processing on this sound signal, and then amplify it

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After amplifying, the output sound signal pushes the speaker

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The main audio mainly plays a role of transit

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Sometimes in Huawei P40 maintenance, the recording cannot be recorded,

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and the other party cannot hear the sound when making a call,

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and there is no sound from the speaker

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At this time, we have to consider the failure of the main audio,

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because both of them are related to it

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If the recording is normal or the other party can hear the sound when making a call,

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but there is no sound from the speaker, or there is no sound when the hands-free is turned on,

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and there is no sound when playing music

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At this time, it is necessary to consider the relevant circuits from the small audio to the speaker,

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and the CPU is generally not considered

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If there is no sound at all, we need to remove the large audio,

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and measure whether there is any problem with the related bus from the large audio to the CPU,

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or whether there is any problem with the working conditions of the large audio

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This is the relevant circuit of the P40 speaker

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That's all for this lesson