I am designing an Operational Transconductance Amplifier whose maximum output current should be 15mA. Using Super Class AB amplifier, I was able to get a maximum output current of up to 2mA. The supply voltage is 5V. So to boost the output current, I need to cascade it with a current amplifier with a small gain. What would be the best way to do so? Can I get a current in mA range using CMOS current mirror technique? Or should I design another opamp and a mosfet/bjt at the output the boost the current?

 

I am designing an Operational Transconductance Amplifier whose maximum output current should be 15mA. Using Super Class AB amplifier, I was able to get a maximum output current of up to 2mA. The supply voltage is 5V. So to boost the output current, I need to cascade it with a current amplifier with a small gain. What would be the best way to do so? Can I get a current in mA range using CMOS current mirror technique? Or should I design another opamp and a mosfet/bjt at the output the boost the current?

You should start with showing us your schematic so we can recommend changes.

 

Can't you just use larger transistors in the output stage?

 

This is the schematic of the OTA stage

 

Can't you just use larger transistors in the output stage?

Well I am supposed to design a two-stage circuit. So I though going with a current amplifier in the second stage would be a good idea.

 

Some ref material -

http://www.ti.com/lit/an/snoa600b/snoa600b.pdf

http://www.ka-electronics.com/images/pdf/Op_Amp_Booster_Stages_pt1.pdf

Regards, Dana.