Shivaki STV-24LEDGR7, Руководство по обслуживанию

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D-class power amplifier
R2A15120FA
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CONFIDENTIAL
12. Notes
The PWM output stage of a D-class amplifier treat a large current of the high frequency. So,please note the
following points besides a basic matter in board such as "Shortest wiring", "Low parasitic impedance making",
and "Part use with an excellent high frequency characteristic".
(1) Reduction of power GND high frequency impedance
There is high-frequency large current pulse on pre-driver power supply pin (DVDD) to drive output Power
MOS FET. If combine GND of capacitor which connect to DVDD with Analog GND, it is possible that high
frequency noise caused by PWM oscillation might influent to any functions of internal circuit or analog circuit
and it caused performance deterioration.
In order to reduce this high frequency noise, it is very effective to reduce GND impedance of high frequency.
We recommend DVDD capacitor connect to Power.
When a power supply line in a common mode or EMI from the I/O line become
problems, the use of the common mode filter is recommended.
(2) Treatment of Exposed die-pad
The main heat radiation of this IC is done from the heat radiation pad by exposure die-pad.
This die-pad is connected with sub straight of IC chip. Please take care in case the leaking current of high
frequency might flow to sub straight at Pulse changing timing. Please design effective heat radiation board
pattern. Otherwise,it would be easy to accumulate heat into the IC under load-short or another stress
conditions.
In that situation,there is a possibility to bring about destruction power Tr.
(3) Treatment of Analog ground pin
In order to reduce the interference with low level signal ground from output stage ground (Vs terminal of
each bridge), please connect low level signal ground to power feed point separately.
(4) Prevention against destruction
This IC have several protection circuits, however over current appears on output, in case of short circuit,
ground fault of output and starting PWM circuit. In that case, overshoot voltage of output terminal become
very large. If this overshoot voltage exceed allowance voltage,it is possible the IC might be destroyed. So,
please design the circuit board carefully, in order not to anytime exceed absolute maximum ratings at each
terminal.
(There is a possibility to be destroy IC in the situation that the pattern layout of the board is different from the
Renesas EVB. In that case,it is recommended to insert Protection diode at the output terminal. )
(5) Q dump measures
When the speaker is always connected with the output terminal of the amplifier, it is possible to omit it
depending on the impedance characteristic of the speaker (Depend on the speaker). Q dump circuit are
always recommended to be used for considering stable operation and safe operation.
These contents are notes for using the D-class power amplifier R2A15120FA, and do not
guarantee all of the operation and a property.
In a board design, please consider these contents and confirm that an operation and a property
are satisfactory by yourself after IC mounting.
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