Hi,
We found that the gain of the SE mode and the BTL mode are clearly mentioned on page 14 of TAS5602 data sheet as below.
So, could you please tell us the BTL gain of TAS5624A as well?
Best Regards,
Kato
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Kato-san,
I asked my colleague to look into this post. Unfortunately, he won't be back in office until next week.
Hi Damian-san,
Thank you for your reply.
Could you please obtain that information from your colleague since I need to inform our customer of our opinion in this week?
Best Regards,
Kato
Hi Damian-san,
Thank you for your cooperation.
I am looking forward to hearing from you.
Best Regards,
Kato
Hi Kato-san,
It's 12.92V/V. If I assume 3.3V rail from the modulator then 1V is 30.3%, so the SE gain (in Vrms/%) = 12.92/30.3 = 0.426 / Modulation level.
Hi Damian-san,
Thank you very much for your advice.
I understood the calculation of the output voltage amplitude as below.
Could you please give me your advice if I have any misunderstanding?
<Condition>
Input Signal : -20dBFS
Gain : 0.4264(SE Mode) / 0.8528(BTL Mode)
Volume Level : 0dB
Modulation Level : 97.7%
for SE Mode :
Output Voltage = 0.1(-20dBFS) * 1(0dB) * 0.4264(Gain) * 97.7(Modulation Level) = 4.166Vrms
for BTL Mode :
Output Voltage = 0.1(-20dBFS) * 1(0dB) * 0.8528(Gain) * 97.7(Modulation Level) = 8.332Vrms
Best Regards,
Kato
Hi Damian-san,
Thank you for confirming.
I will contact you if I have any questions.
Best Regards,
Kato
Hi Damian-san,
Could you please confirm the unit of the SE gain just in case?
I doubt whether Vrms/% of the unit which you mentioned is correct since that gain is too high, so I am considering as below.
Is my understanding correct?
The gain in Vrms/% is 0.151 if the unit of 0.426 is Vpp/%.
Best Regards,
Kato
Hi Damian-san,
I obtained 0.289Vrms/% as the gain of the BTL mode by evaluating TAS5624A evm.
So, I believe that 0.151Vrms/% is maybe correct as the gain of the SE mode.
Best Regards,
Kato
Hi Kato-san,
Measuring is always best. Can you share your measurement details? Input PWM voltage rail and duty cycle used?
Hi Damian-san,
I have evaluated the evm which TAS5538 and TAS5624A are mounted, those results are shown as below.
Could you please give me your advice if I have any misunderstanding?
(a) case1
PVDD : 28[V]
PWM Input Voltage Rail : 3.3[V]
Input Signal : 0[dBFS]
Volume Level : -12[dB]
Modulation Index Limit : 93.7[%]
Vrms for BTL : 6.779[Vrms]
---> Calculated Gain : 0.2880[Vrms/%]
(b) case2
PVDD : 28[V]
PWM Input Voltage Rail : 3.3[V]
Input Signal : 0[dBFS]
Volume Level : -6[dB]
Modulation Index Limit : 93.7[%]
Vrms for BTL : 13.560[Vrms]
---> Calculated Gain : 0.2887[Vrms/%]
(c) case3
PVDD : 28[V]
PWM Input Voltage Rail : 3.3[V]
Input Signal : 0[dBFS]
Volume Level : -3[dB]
Modulation Index Limit : 93.7[%]
Vrms for BTL : 19.150[Vrms]
---> Calculated Gain : 0.2886[Vrms/%]
Best Regards,
Kato
Kato-san,
Thanks for sharing. Yes you are correct based on the assumption that 0dB (fullscale) is 2Vrms.
Hi Damian-san,
Thank you for confirming.
I will contact you if I have additional questions.
Best Regards,
Kato