DC-DC converters are power electronic circuits that convert a DC voltage to a different DC voltage...

 

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DC-DC converters are power electronic circuits that convert a DC voltage to a different DC voltage level, often providing a regulated output. One way of obtaining a DC output is to insert a low-pass filter after the switch. The diode provides a path for the inductor current when the switch is opened and is reverse-biased when the switch is closed. This circuit is called a buck converter or a step-down converter because the output voltage is less than the input. a) Sketch the buck converter circuit (3 marks) b) Design a buck converter to produce an output voltage of 9V across a 25 ohm load resistor. The output voltage ripple must not exceed 0.35 percent. The DC supply is 24V. Design for continuous current with the value of new inductor is 15% larger and the switching frequency is 50 kHz. Sketch the buck converter circuit, specify the duty ratio, the values of inductor and capacitor, the rms current in the inductor. Assume the components are ideal. (22 marks) DC-DC converters are power electronic circuits that convert a DC voltage to a different DC voltage level, often providing a regulated output. One way of obtaining a DC output is to insert a low-pass filter after the switch. The diode provides a path for the inductor current when the switch is opened and is reverse-biased when the switch is closed. This circuit is called a buck converter or a step-down converter because the output voltage is less than the input. a) Sketch the buck converter circuit (3 marks) b) Design a buck converter to produce an output voltage of 9V across a 25 ohm load resistor. The output voltage ripple must not exceed 0.35 percent. The DC supply is 24V. Design for continuous current with the value of new inductor is 15% larger and the switching frequency is 50 kHz. Sketch the buck converter circuit, specify the duty ratio, the values of inductor and capacitor, the rms current in the inductor. Assume the components are ideal. (22 marks)