MP8716 – SYNCHRONOUS STEP-DOWN CONVERTER WITH INTERNAL MOSFETS

MP8716 Rev. 0.9

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13

4/23/2010

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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 is:

Duty cycle is high: D=

IN

OUT

V

V

>65%

In this case, an external BST diode is

recommended from the VCC pin to BST pin, as

shown in Figure 5

SW

BST

MP8716

C

L

BST

External BST Diode

VCC

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.