TAS5719: TAS5719 output PWM duty cycle

Akihisa Tamazaki

Part Number: TAS5719

Hello team,

I have a question about output level.
TAS5719 is open-loop Audio ampliffer, soI belieave its output lebel to speaker depends on the PVDD, however I think the PWM duty cycle (Modulation Level) was determined.

What is the PWM duty cycle (Modulation Level) of TAS5719 output in the following case.

Input : 0dBFS
DAP : set 0dB at all registers (such as EQ,DRC, Power Limit and etc)

Your help would be so appreciated.

Best Regards,
Akihisa Tamazaki

over 7 years ago

0 Diego Melendez over 7 years ago

TI__Guru 57800 points

Hi, Tamazaki-san,

As you mention, the TAS5719 is an open loop amplifier and the output level depends on the power supply voltage. This is a Class-D amplifier where the outputs are PWM signals whose high level will be PVDD. The duty cycle of the PWM outputs is derived from the I²S input, if no I²S input is provided, the duty cycle will be 50%.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 Akihisa Tamazaki over 7 years ago in reply to Diego Melendez

TI__Genius 10915 points

Diego,

Thank you for oyur reply. I understand TAS5719 is open loop class-D ampkifier.
I would like confirm PWM signals in the specific case. Please see the pptx file.
/cfs-file/__key/communityserver-discussions-components-files/6/TAS5719.pptx

My understanding is correct or not?

Your advise would be so appreciated.

Best REgards,
Akihisa Tamazaki

0 Sadanori Kato over 7 years ago in reply to Akihisa Tamazaki

Guru 36490 points

Hi Tamazaki-san,

Excuse me for cutting in.

The calculating formula of the output voltage for BTL configuration is as below.

Output Voltage [Vrms] = 2 * PVDD * (1/(2*SQRT(2)) * ΔDuty Cycle
ΔDuty Cycle = Input Signal * Volume Level * Modulation Level

PVDD              : 12 [V]
Input Signal      : -20 [dBFS]
Volume Level      : 0 [dB]
Modulation Level : 97.7 [%]

Output Voltage = 2 * 12 * (1/(2*SQRT(2)) * 0.1 * 1 * 0.977 = 0.829 [Vrms]

Best regards,
Kato

0 Akihisa Tamazaki over 7 years ago in reply to Sadanori Kato

TI__Genius 10915 points

Kato-san,

Thank you. I understand.

The case I would like to know is
Input Signal : 0 [dBFS]
Volume Level : 0 [dB]
Modulation Level : 97.7 [%] = Modulation Limit

Maximum Duty Cycle = 1* 1* 97.7[%] =97.7%

Best Regards,
Akihisa Tamazaki

Audio

Audio forum

TAS5719: TAS5719 output PWM duty cycle