Regulated Power Supply for LTP/VAS needed?

[danny92]

Hi everyone,

With this design I should use a regulated power supply for the LTP/VAS, because of low PSRR? Or that's not necessary, I've seen some designers, splitting the reference current resistor that connects to ground at the current sources and then connecting the middle point to a capacitor and this capacitor to Vcc or to ground, this increases the PSRR? Or the capacitor has other reasons for being used?

Thank you for your help,
Best regards,
Daniel Almeida

 

[jaycee]

The main reason to use a regulated supply on a MOSFET amp, is where the voltage is higher in order to get maximum drive capability out of the MOSFETs.

 

[nigelwright7557]

I use a 33r in series with the supply and a 470uf to ground after the 33r on my LPT/VAS stages.

I noticed that without this I was getting a bit of hum on the output.

 

[danny92]

Right, thank you very much for your help