MP2488 – 2A, 200kHz, 55V HIGH-POWER LEDS DRIVER
3. Determine if the second compensation
capacitor (CCOM2) is required, which is connected
from COMP pin to GND. It is required if the ESR
zero of the output capacitor is located at less
than half of the switching frequency:
1
2 COUT
RESR
fS
2
If this is the case, then add the second
compensation capacitor (CCOM2) to set the pole
fP3 at the location of the ESR zero. Determine the
CCOM2 value by the equation:
CCOM2
COUT RESR
RCOM
External Bootstrap Diode
An external bootstrap diode may enhance the
efficiency of the regulator. In below cases, an
external BST diode is recommended from the 5V
to BST pin:
There is a 5V rail available in the system;
VIN is not greater than 5V;
VOUT is between 3.3V and 5V;
The bootstrap diode can be a low cost one such
as IN4148 or BAT54.
5V
BST
MP2488
SW
Figure 2—External Bootstrap Diode
MP2488 Rev. 1.0
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11
6/20/2011
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