Hi all
I do have a school project to do: a 3 stages power amplifier circuit.
+-16V power supply
+- 175mV input signal swing corresponding to +- 14V output swing. (closed loop voltage gain = 80).
open loop gain of the 3 stages ampli = 2450
resistive load >= 10ohm
amplifier input resistence >= 10kohm
bandwidth >=80 kHz
phase margin 80°
efficiency >=60%
THD <=1%
I have to use only transistors listed in the ltspice database.
That's why I had to choose 2N3055 (npn) and D45H11 (pnp): the only ones capable of dealing with 10W power dissipation (I've read that from their datasheets).
I've started the project from the output stage.
Class AB output stage using a Vbe multiplier as biasing and a current mirror (current source as first attempt).
I just wanted to see if I could get it right... Something went wrong... Obviously...
I gave it a 14V sinusoidal input with -1.3 DC offset and I hoped to see sinusoidal 14V oscillating around 0V as vo.
I got a distorted sinusoidal waveform oscillating around -280 mV.
How can I fix that? What am I doing wrong?
Any suggestions is appreciated.
Cheers
I do have a school project to do: a 3 stages power amplifier circuit.
+-16V power supply
+- 175mV input signal swing corresponding to +- 14V output swing. (closed loop voltage gain = 80).
open loop gain of the 3 stages ampli = 2450
resistive load >= 10ohm
amplifier input resistence >= 10kohm
bandwidth >=80 kHz
phase margin 80°
efficiency >=60%
THD <=1%
I have to use only transistors listed in the ltspice database.
That's why I had to choose 2N3055 (npn) and D45H11 (pnp): the only ones capable of dealing with 10W power dissipation (I've read that from their datasheets).
I've started the project from the output stage.
Class AB output stage using a Vbe multiplier as biasing and a current mirror (current source as first attempt).
I just wanted to see if I could get it right... Something went wrong... Obviously...
I gave it a 14V sinusoidal input with -1.3 DC offset and I hoped to see sinusoidal 14V oscillating around 0V as vo.
I got a distorted sinusoidal waveform oscillating around -280 mV.
How can I fix that? What am I doing wrong?
Any suggestions is appreciated.
Cheers
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