Question

Question 1 As a power electronics engineer, you have been contracted by a mobile phone manufacturing company, STK Mobile, to design a converter to supply power to the microprocessors for the mobile phones. Your task is to design a converter to meet the following specifications: 1. the microprocessors operate effectively at 8 V and 1 A. 2. continuous current conduction mode at all the time. 3. peak-to-peak inductor current should not be more than 30% of its average value at all operating conditions. 4. output voltage ripple should not be more than 2%. NOTE: Typical output voltage of batteries for the mobile phones range from 3.6 V to 12 V DC, depending on the charge state. You are required to write a short report for your design. The report should cover at least the following, with explanations: (a) block diagram, explaining how the whole system would operate. (b) your choice of converter(s) and its (their) circuits. Explain the operation of your choice of converter(s). (c) derive expressions for the relationships between output and input voltages and currents for your choice of converter (s).

Question 1 As a power electronics engineer, you have been contracted by a mobile phone manufacturing company, STK Mobile, to design a converter to supply power to the microprocessors for the mobile phones. Your task is to design a converter to meet the following specifications: 1. the microprocessors operate effectively at 8 V and 1 A. 2. continuous current conduction mode at all the time. 3. peak-to-peak inductor current should not be more than 30% of its average value at all operating conditions. 4. output voltage ripple should not be more than 2%. NOTE: Typical output voltage of batteries for the mobile phones range from 3.6 V to 12 V DC, depending on the charge state. You are required to write a short report for your design. The report should cover at least the following, with explanations: (a) block diagram, explaining how the whole system would operate. (b) your choice of converter(s) and its (their) circuits. Explain the operation of your choice of converter(s). (c) derive expressions for the relationships between output and input voltages and currents for your choice of converter (s).

How would you solve this question?

Answer 1

a) Block Diagram - <De-De conva) LOAD Switch mode + Full Bridge LC type Feedback <Filters <Rectifier)

*) Explanation → From the AC power supply, sinusoidal voltage will be converted to de by Full Bridge Rectifier filter will reduce ripple of de wave SM de-de converter will reduce the magnitude of de voltage. → Feedback will help to maintain constant de output voltage LI Ti ERL im AP3 EN 263 DI Volt) -C2 + GolHZ L2 D4 D2 OF Gate Сек- v=2300 <ec = Control circuit Di, D2, D3, D4 - Normal diodes Ds = High frequency diode: sa power mosfet (IRFP450) Ti = Flyback transformer,

explanation through diagram 1 V₂ Vo The converter used as de-de conversion medium is - Flybaew converter. Design of flyback, converteri Assuming V2 = pure des { ADV2} <D = Duty ratic) Lets set, (Nz] N1) (1:10) so, as, V2 = 2(%)82 for, Vo= qV; Ve 207.07 V

D= (Na)(vo/v2) 0.38 whew, s son: N2 L2h { t = D/f) Vo 4) v2 + N1 Whew, S off: di to=0 2 <t2 = (1-D)/> La dan using equ. and (di) = A IL = N2X KXD11-0) NI FL2 013 A Lets, say, f = 100 k H2 { switching freq. of 5) for, AIL = 307. of IA Nz V₂ D (1-D) Ni f L₂ 50, 5013 so, L2 > 48.78 MH Lets, take, L2 = 50ult

Again, it can be shown that AVO NzV2D(ID) Ni 8 frez la - As, given that, AV, 2. of 8V = 0.16V soy C3 ) 1.21 MF so, Lets take, C3 = 1.3MF / Filter design! L = 10MH ) 22 I'mF This will give smooth de output. #> eseplanation Flyback corn. through graph I229 LEDIf Ile