MP2565 datasheet(15/20 Pages) MPS

15 / 20 page

MP2565 – 2.5A, 4MHz, 50V STEP-DOWN CONVERTER

MP2565 Rev. 0.91

www.MonolithicPower.com

4/19/2011

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

External Bootstrap Diode

It is recommended that an external bootstrap

diode be added when the input voltage is no

greater than 5V or the 5V rail is available in the

system. This helps improve the efficiency of the

regulator. The bootstrap diode can be a low

cost one such as IN4148 or BAT54.

MP2565

BST

0.1

Figure 3—External Bootstrap Diode

This diode is also recommended for high duty

cycle operation (when VOUT /VIN >65%) or low

VIN (<5Vin) applications.

At no load or light load, the converter may

operate in pulse skipping mode in order to

maintain the output voltage in regulation. Thus

there is less time to refresh the BST voltage. In

order to have enough gate voltage under such

operating conditions, the difference of (VIN –

VOUT) should be greater than 3V. For example,

if the VOUT is set to 3.3V, the VIN needs to be

higher than 3.3V+3V=6.3V to maintain enough

BS voltage at no load or light load. To meet this

requirement, EN pin can be used to program

the input UVLO voltage to Vout+3V.

MP2565 Datasheet(PDF) 15 Page - Monolithic Power Systems