Question

Q5. 5.a. Sketch the circuit arrangement of a DC-DC boost (step up) converter, clearly labelling each circuit element [4 тarks] [Refer to lecture notes] Sketch all significant operating waveforms for this converter for continuous conduction conditions over two switching periods, in particular showing 5.b. the voltage across the main switching device and the boost diode. [2 marks the voltage across the inductor [3 тarks] the current flowing through the inductor [3 marks [Refer to lecture notes] 5.c. The DC-DC boost converter is required to produce a 24V output from an input voltage that varies over the range 8-16V. It switches at a frequency of 20 kHz, has an output capacitance of 470HF, and feeds a load of at least 6W Calculate the duty cycle range required to achieve this specification, assuming continuous conduction 5.c.i [4 marks] [Dmax = 0.67; AND [D min = 0.33] 5.c.ii Calculate the minimum inductance required for the converter to operate in continuous mode over the entire input voltage range [4 marks [Lf 355.564H]

Answer 1

BooST Converte 5-9 Sw

is TLmax AIL TLmin Yde min Vac-Ve st TLmin Vo -Vo -Vo Vac t AVo T

No24 V 5.C S - 20 KH t 오식 2 \-D |-D -- = O 2 2쳐 &3 3 Dmin 2 3 0 33

DCI-D) RT DCI-D RT 24 R 2 2ux24-96 0.33 1-033) x 9 2 x 26x103 355 52 MH