Some question about AGC in PA design
Hi,
Frankly i am not understand what you want. So please expalin again and give some more detils or skech
David
I mean the power control range is not very large,how can i make the output power variable between -17dbm and 5dbm through change the tail current?
tail current? do you want to control the current to arrive the AGC aim, in fact, you can use a attenuator before the amplifier to arrive this aim, how about your idea?
You should post the schematics of your design.
Actually, you can use switch to turn on and off the cascode transistors to tune the range, that is tune the current.
Hi,
You should use voltage control attenuator [for example AT108 macom],
If you want I will put on the schematic on net of my PA with AGC
Simple agc design with LM324
David
Thans for you help me , I still don't know the mathod you suggest,the PA strccture I adopt is from NODIC.Does someone familiar this circurt ,the biggest problem is the drive stage ,can you detail it ? thank you ![/quote]
plike post your circuit so we can give you a propper sugesstions and maybe a solution.
MY SCHEMATIC.THANKS!
Hi,
David.
Could you please post the schematic on net of your PA with AGC
Simple agc design with LM324.
Added after 13 minutes:
I am designing a cmos RF PA for bluetooth. The PA's output power must vary from -30dBm to 0dBm. Now i change the size of output cmos transistor to control the output power. Controlling the tail current can also control the output power. But the control range is not large. David said, PA's power control can be realized by adding a voltage attenuator. Perhaps this is an good method.
David, Could you please post the schematic on net of your PA with AGC
Simple agc design with LM324?
Hi,
I attach below AGC with At108 [MACOM] for Power Amp. with LM324.
David