LM4991: Usage

Hi Ti,

The load is 8Ω.

Best regards,

Hi Atsuo,

it seems this is not a good design. 

the output level can't exceed the supply voltage, and in fact, usually it is a little lower than the supply voltage and there is loss inside the chipset.

and regarding the input signal, if it equals to the power supply, it may cause clipping.

Br,

Wenbin

Thank you for your prompt reply.

LM4991 is a bridge output, right?

In case of 6Vpp, I think the outputs of Vo1 and Vo2 are 3V, but is it different?

If so, I don't think the supply voltage is exceeded.

Best regards,

Hi Ti,

Sorry, I misunderstood.

My understanding is that Vo1 and Vo2 are outputs of 1V to 4V, respectively.

Therefore, I am aware that the supply voltage is not exceeded.

Best regards,

Hi Atsuo,

Yes, if the input signal is 5Vpeak to peak, it is ok. 

and your design should be achieved.

Br,

Wenbin

Thank you for your prompt reply.

If 6Vpp is output into 8Ω load, the power will be 2.25W.

The datasheet states 1.5W (Typ.) when VDD=5V and RL=8Ω.

The graph also shows only up to 1.5W. (Figure 24)

Is there a problem?

Best regards,

Thank you for your careful explanation.

I now understand how to use it and that there is no problem.

Best regards,