low power audio amplifier IC

[mozikluv]

hi,

this concerns low power audio amp ic with output of 600mw to 11w, all this amps have either bootstrap pin, if none a feedback circuit is provided.
my question is what would be the outcome of the sound produced when possible action is taken:
1. the bootstrap pin is not used with no feedback circuit provided
2. the bootstrap pin is unused but with feedback circuit provided
3. the bootstrap pin is used together with a feedback circuit

thanx

 

[stevez]

I'd appreciate it if anyone could explain what the bootstrap pin does - something I've wondered about for some time.

 

[mozikluv]

hi stevez,

if my memory serves me right, the bootstrap pin is used to pull up the voltage to supply level or a little bit higher and this also serves as a feedback path. that pin is connected to the base of the driver transistor.

the reason why am posting this query is because i saw a post saying that he remove the cap connected between the output and the bootstrap pin and the sound came out better. i just can't remember where i saw that post.

on my next post i'll try to give the proper answer to your question

 

[mozikluv]

audio ic bootstrap pin

hi stevez,

the bootstrap pin has 2 functions.
1. a capacitor can be connected between the output and this pin. the cap is used to set the low freq. pole
2. a resistor can be connected between the supply rail and this pin. the resistor is used to set the drive current of the output stage.