hi
i am building dc dc boost converter.....volt in 5v...vout 8v .....load 2ohm...n-ch Mosfet irlz44 ...mcu pic16f628a to drive the mosfet...inductor 3.3u 18A Current - Saturation 32A..........computer power supply...now the problem is that: when start with 25khz 1% duty the voltage step up a little ...25khz 10% duty the voltage step up a little.....25khz 20% duty the voltage step up a little....25khz 30% duty the voltage start to fall!...25khz 40% duty the voltage fall more!! what is the problem with my setup? i had tried 20khz and 30khz and 60 khz!...at low duty the voltage step up little then its begin to fall and fall and fall
hope any one help me
my inductor http://www.digikey.com/product-detail/en/0/SRP1250-3R3MCT-ND
i am building dc dc boost converter.....volt in 5v...vout 8v .....load 2ohm...n-ch Mosfet irlz44 ...mcu pic16f628a to drive the mosfet...inductor 3.3u 18A Current - Saturation 32A..........computer power supply...now the problem is that: when start with 25khz 1% duty the voltage step up a little ...25khz 10% duty the voltage step up a little.....25khz 20% duty the voltage step up a little....25khz 30% duty the voltage start to fall!...25khz 40% duty the voltage fall more!! what is the problem with my setup? i had tried 20khz and 30khz and 60 khz!...at low duty the voltage step up little then its begin to fall and fall and fall
hope any one help me
my inductor http://www.digikey.com/product-detail/en/0/SRP1250-3R3MCT-ND
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