//Chapter 10_Special Purpose Amplifiers //Caption : Class B Power Amplifier //Example10.3: A class-B audio power amplifier has a supply voltage of abs(Vcc)=15V. The closed loop gain Av=50 and the amplifier has to deliver 10W of power into an 8 ohm load.Find: //a)the peak output voltage swing //b)the peak output current swing //c)the input signal required(rms) //d)the total power from the power supply //e)the power dissipated in the amplifier //f)the power conversion efficiency clear; clc; //a)Solution: Po=10;//power in Watt Rl=8;//load resistance in Ohm; Vorms=sqrt(Po*Rl);// since output power Po=Vorms^2/Rl Vom=sqrt(2)*Vorms;//peak output voltage swing disp('V',abs(Vom),'The peak output Voltage swing:') //b)Solution: Iom=Vom/Rl; disp('A',abs(Iom),'The peak output current swing is:') //c)Solution: Av=50;//closed loop gain Vsrms=Vorms/Av; disp('V',Vsrms,'The input rms signal required is:') //d)Solution: Vcc=15;//absolute value of poer supply in volt Pin=2*Vcc*Iom/%pi;// since Iorms*2^(1/2)=Iom disp('W',Pin,'The total power from power supply is:') //e)Solution: Pd=(2/%pi)*Vcc*sqrt(2*Po/Rl)-Po; disp('W',Pd,'The power dissipated in the amplifier is:') //f)Solution: n=(Po/Pin)*100; disp('%',n,'The power conversion efficiency is:') //Note: //Vcc,Vom and Iom can be of either polarity but here only absolute value is considered and calculated