MP2380 – 5A, 21V, 600KHz STEP-DOWN CONVERTER

MP2380 Rev.1.2

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10

5/26/2008

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External Bootstrap Diode

An external bootstrap diode may enhance the

efficiency of the regulator, the applicable

conditions of external BST diode are:

Duty cycle is high: D=

IN

OUT

V

V

>65%

In these cases, an external BST diode is

recommended from the output of the voltage

regulator to BST pin, as shown in Fig.5

MP2380

SW

BST

C

L

BST

C

5V or 3.3V

OUT

External BST Diode

IN4148

+

Figure 5—Add Optional External Bootstrap

Diode to Enhance Efficiency

The recommended external BST diode is

IN4148, and the BST cap is 0.1~1µF.

By using this circuit, 5V input voltage can output

3.3V and 2.5V with just 30mA load.