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LP8553: Boost Conversion Ratio

Part Number: LP8553

Data sheet of LP8553 shows a max boost conversion ratio of 10 with Fsw = 1.25 MHz.  Can this range be increased by reducing the switching frequency? If limit is due to a min off-time requirement,  then reducing the frequency might increase the allowed conversion ratio.

Design would like to boost from 2.7V to 30V, which is a ratio of 11.11

  • Hi Mark,

    Thank you for the question. 

    Yes, conversion ratio is limited by the min off-time and data sheet does not have that spec. But with 10V/V ratio, min off time seems to be 80ns at 1.25MHz. 

    If you can select 625kHz, off-time with new conversion ratio (11.11V/V) is 144ns, which looks promising. However, it is good to confirm on the bench. There might be other parameters such as temp, rise & fall times that affect this off-time. So, we may not guarantee across the spec  if >10V/V is used.

    Best,

    -Harini