DN85 Datasheet, PDF (1/6 Pages) Zetex Semiconductors – ZXSC400 1W/3W buck LED drivers

DN85
ZXSC400 1W/3W buck LED drivers
Ray Liu, Applications Engineer, Zetex Semiconductors
Description
In Figure 1, ZXSC400 is configured as a high efficiency buck LED driver. The target applications
are either 1W (350mA) or 3W (700mA) drivers for white LED driven from a 4 cell battery, or a 2
alkaline cell input for flashlights. The supply voltage for ZXSC400 reference design is:
V_IN = 3.8V to 6V.
Parts lists for 1W and 3W design are shown in Table 1 and Table 2 respectively. Performance data
is measured based on two different LED's V_F binning with 0.3V V_F difference.
C3
V_IN = 4V to 6V
L1
D1
C2
U1
V_CC V_DRIVE
Q1
Stdn
V_FB
C1
GND ^ISENSE
ZXSC400
R3
R2
R1
Figure 1 Schematic diagram
Issue 1 - August 2007
1
© Zetex Semiconductors plc 2007
www.zetex.com