FDA903D-EHT datasheet(51/82 Pages) STMICROELECTRONICS

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FDA903D

Additional features

12.4

Real time load current monitoring

FDA903D provides the current sensing function, an innovative feature for real time load

monitoring. The continuous load monitoring enables many applications that could check,

control and optimize the speakers operation for their entire life.

The current sensing circuit is the basis for the following diagnostic features: DC Diagnostic,

Open Load in Play Detector and Output Current Offset Detector.

When the user enables the real time load current monitoring, the data collected by the

current sensing circuit is also properly processed and directly provided to the user through

I2S bus.

The overall current sensing path is shown in Figure 63:

Figure 63. Current sensing path

In particular, the output data represents the following current: ICS=(IOUTP-IOUTM)/2.

12.4.1

Result communication and I2C control

In order to enable the real time load current monitoring, the user must set IB8[3-1]='011'.

The default current sensing full scale is 8 A, but it can be configured through IB8[7,6].

The current sensing stream is provided on I2Stest pin according to the following

instructions:



The data stream matches the same timings of I2S clock and I2S word select, according

to the configuration set trough IB0[5-1] and IB1[7-5]. The feature is available both in I2S

and in TDM mode, guaranteeing the maximum flexibility.



The I2Stest pin data could be generated on the I2S clock rising or on falling edge. The

selection is possible properly setting IB7[1], thus adapting to user system

requirements.



Each word is composed of 15 significant bits, placed in the 15 MSB of the 32-bits word

marked by I2S word select slot. The words are coded with two's complement notation.

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