Question

1. We are given a DC-DC converter as shown below. If the duty cycle is the fraction of each period that the switch is closed:

Please answer parts a & b with detail. This problem will help me study for my upcoming exam.

1. We are given a DC-DC converter as shown below. If the duty cycle is the fraction of each period that the switch is closed: a. Give the function that describes in terms of duty cycle. What is the output voltage if the duty cycle is 50%, what is the output voltage? If the duty cycle is 100%, what is the output voltage based on you equation? If you reason through what the circuit is actually doing in the 100% duty cycle case, explain why this may not make much sense. b. Let l'-5W, D-05, RL-50Ω C-100μF, L-5μΗ , and clock the switch at 10 MHz. What is the ripple in the output voltage? (O L C

Answer 1

when switch is ON V_L(on) = V_1 I_(c ON) = -I_ compositefunction when switch is oFF V_L()FF) = V_ compositefunction I_c(OFF) + I_L + I_ compositefunction = 0 I_c(OFF) = -(I _ compositefunction + I_L) From voltage second balance V_L ON T_ON + V_L(OFF) T_(OFF) = 0 V_1 DT + V_ compositefunction T - V_ compositefunction DT = 0 V_s DY = -V_ compositefunction (1 - D) T V_ compositefunction = -V_s D/1 - D For V_ compositefunction polaril V_ compositefunction = V_s D/1 - D For \r\n V_ compositefunction/V_1 = D/D - 1 When D = 50% = 0. V_ compositefunction/V_1 = 0.5/1 - 0.5 = 0.5/0.5 = 1 V_ compositefunction/V_1 when D = 100% = 1. V_ compositefunction/V_1 = 1/1 - 1 = 1/0 = infinity V_ compositefunction = infinity But the above condition practically can not be possible The ripple voltage for is delta V_C = I_ compositefunction D/cf V_1 = 5, D = 0.5, R_L