STMicroelectronics STEVAL-L3751V12, Руководство пользователя

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5 Board setting capability
The STEVAL-L3751V12 overcurrent limit is set to 18 A (average) through R5. Increasing or decreasing this
resistor, it is possible to increase or decrease the current limit (check the datasheet or eDesignSuite for further
details).
The switching frequency is set through R10. It can be changed from 100 KHz to 1 MHz. Considering that the
increasing of Fsw can charge a large amount of self-heating (check the datasheet or
eDesignSuite for further
details).
The
STEVAL-L3751V12 is a 100 W power evaluation board. So, it is considered IoutMax = 15 A for V
OUT
= 5 V
and IoutMax = 10 A for V
OUT
= 12 V. For high output power, we suggest to use a 200 LMF air flow to decrease
the self-heating and avoid that OTP occurs.
The high input current can increase the EMI inductor temperature. In this case, it is possible to shortcut the
inductor by using R18 = 0 Ohm or selecting an inductor with a higher Irms.
The V
IN
UVLO is set to 14.5 V. However, it is possible to change the V
IN
UVLO by changing the R9 and R19
partition (check the datasheet or eDesignSuite for further details).
V
OUT
can be selected from 5.07 V to 12.18 V by using J1.
It is possible to change V
OUT1
and V
OUT2
by selecting different values for R12, R13 and R21.
• V
OUT1
→pin 6 to GND→V
OUT
= (R12 +R13//R21)/(R13//R2) 1 x V
FB
where V
FB
is fixed to 0.8 V.
• V
OUT2
→ pin 6 to floating → V
OUT
= (R12 +R13)/R13 x V
FB
where V
FB
is fixed to 0.8 V (see the L3751
datasheet for further details).
UM3024
Board setting capability
UM3024 - Rev 1
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