TB429 Datasheet, PDF (1/7 Pages) Intersil Corporation – Using the EL7515 Demo Board

®
Technical Brief
Using the EL7515 Demo Board
June 7, 2004
TB429
The complete schematic of EL7515
demo board is shown in Figure 1. With
different components stuffed, this
demo board can easily be configured into the applications
shown in this technical brief. The standard demo board
being sent out is the complete 5V to 12V converter shown in
Figure 2, which occupies less than 0.4 in² area with
components on top side only. Layout diagrams are given at
the end of this document.
1. V_IN = 2V-5.5V. Can be higher with higher voltage rated
C₁
2. V_O = 12V. Can be set according to the following formula:
V_O
=
V_FB
×



1
+
RR_{-----21- }
where V_FB is shown in the V_FB vs V_DD curve.
3. I_O - up to 600mA depending on input voltage, provided
that diode and inductor can handle the corresponding
currents (refer to data sheet for the chart)
4. Switching frequency - can be set by R₃
5. R₄ can be 10Ω - 51Ω if V_O is less than 10V. If V_O is larger
than 12V, it can be calculated by:
R₄
=
V_-----O-----–_-----1_---0_--
I_DD
where I_DD is a function of switching frequency, as shown
in the I_DD vs F_S curve.
V_IN
R₇
R₈
C₂₁
D₂₁
C₁₄
D₁₂
C₁₁
D₁₁
L₁
D₁
C₁
R₄
1 PGND
LX 10
2 SGND
VDD 9
R₃
3 RT
R₆
EN
4 EN
FB 8
SS 7
C₄
C₃
5 LBI
LBO 6
V_O4
C₂₂
V_O3
C₁₅
V_O2
C₁₂
C₁₃
V_O1 Q₁ L₂
C₅
C₆
V_O11
C₈
R₂
R₁
C₇
R₉
LBO
FIGURE 1. COMPLETE SCHEMATIC OF EL7515 DEMO BOARD
V_IN
R₆
L₁
D₁
C₁
R₄
1 PGND
LX 10
2 SGND
R₃
3 RT
4 EN
VDD 9
FB 8
SS 7
C₄
R₂
C₃
R₁
5 LBI
LBO 6
FIGURE 2. 5V TO 12V CONVERTER
V_O1
C₅
C₆
C₁₀
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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