Why do we use DC-DC converter for power supplies in Mobiles

[dhasmana]

Why do we use DC-DC converter for power supplies in Mobiles (battery chargers etc.) regulators? Is it high current requirement?
Linear LDO will take more area? Linear regulators have higher efficiency than DC-DC SMPS! or regulation required is not very good?
please comment.

Regards,
Jitendra Dhasmana.

 

[wolly]

Re: Why do we use DC-DC converter for power supplies in Mobi

basically less space required as most controllers and mosfets are available in SMD
more efficient
less heat so smaller or no heat sink required
more current

 

[haff99]

Re: Why do we use DC-DC converter for power supplies in Mobi

Typically for mobile applications battery life is key. Switchers are much more efficient then linear regulators. Hence you save power and generate less heat. For instance is you had a linear regulator and needed to step down from 3V to 1V at 1A your efficiency is only 33%. The linear will generate a lot of heat. A switcher can do the same conversion and obtain an efficiency in the 80%90% range.

 

[dumbfrog]

most are boost circuits, boosts 1.2V to 3.3V etc
LDO can't do that (limited by LDO's vdd). If you have Vdd=1.2V, u can't convert it to 3.3V using a LDO.

DC-DC will generate more noise but more efficient

 

[cloudfly88]

Even there are many disadvantages of DCDC for used in battery application for EMI, ripple is large, but the high efficiency is the advantage than LDO.