EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: EAvMx on August 10, 2021, 03:09:59 pm
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Hello, I'm looking for a circuit capable of receiving 5-24V in its input and output 5V and a maximum of 500mA.
As far as I know, for LDOs worst case scenarios are Vin=24V where the LDO would waste too much power dissipated and Vin=5V where Vout would be lower than 5V because of the voltage dropped by the LDO.
The latter being the same problem I'm facing while searching for Buck Switching Regulators.
I found the TPS55165-Q1 but unluckily, its Vin needed to startup is 5.3V and it wouldn't work for me.
I've been told that what I need is a SEPIC IC that boosts/bucks the input voltage to a fixed output voltage but so far after reading lots of datasheets I haven't been able to find a proper IC. Can someone please help me out recommending one?
Thanks!
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There are "low dropuout" buck regulators with P-cannel MOSFETs out there. For example, the common on auction sites XL4016 advertises 300mV dropout, presumably at full 8A load, which appears to be solely due to 40mΩ Rds(on) and could become 20mV at 0.5A. Because it's PMOS, it can be switched on 100% of time. But it needs 8V to run.
Another potential alternative to complex switching topologies could be paralleling an ordinary linear LDO with an ordinary buck and adding some hack to turn on the linear reg when the buck can't work. But with linear LDOs it seems to be "cheap, ultlra low dropout, high input voltage range, pick two".
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maybe something like that:
https://www.ebay.de/itm/272638443626 (https://www.ebay.de/itm/272638443626)
https://www.ebay.de/itm/311568532268 (https://www.ebay.de/itm/311568532268)
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Easiest is one of the small isolated DC/DC modules, eg, from Traco www.tracopower.com (http://www.tracopower.com).