LM3697_15 Datasheet, PDF (27/43 Pages) Texas Instruments – High-Efficiency Three-String White LED Driver

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LM3697
SNOSCS2C – NOVEMBER 2013 – REVISED OCTOBER 2015
V_IN = 3.6 V, full-scale current = 20.2 mA, LEDs are WLEDs part # SML-312WBCW(A), Typical Application Circuit , T_A = 25°C
unless otherwise specified. Efficiency is V_OUT × (I_HVLED1 + I_HVLED2 + I_HVLED3)/(V_IN × I_IN), matching curves are (ΔI_{LED_MAX}/I_{LED_AVE}).
Two String, L=4.7µH, 500kHz
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
C002
Top to Bottom: 2x3, 2x4, 2x5, 2x6, 2x7, 2x8, 2x9, 2x10 (LEDs)
Two String, L=4.7µH, 1MHz
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
C002
Top to Bottom: 2x3, 2x4, 2x5, 2x6, 2x7, 2x8, 2x9, 2x10 (LEDs)
Figure 30. Boost Efficiency vs V_IN
Figure 31. Boost Efficiency vs V_IN
One String, L=4.7µH, 500kHz
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
C002
Top to Bottom: 1x3, 1x4, 1x5, 1x6, 1x7, 1x8, 1x9, 1x10 (LEDs)
Figure 32. Boost Efficiency vs V_IN
One String, L=4.7µH, 1MHz
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
C002
Top to Bottom: 1x3, 1x4, 1x5, 1x6, 1x7, 1x8, 1x9, 1x10 (LEDs)
Figure 33. Boost Efficiency vs V_IN
Three String, L=22µH, 500kHz
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
0.00 12.00 24.00 36.00 48.00 60.00
ILED (mA)
C002
Top to Bottom: 3x3, 3x4, 3x5, 3x6, 3x7 (LEDs)
Figure 34. Boost Efficiency vs I_LED
Three String, L=22µH, 1MHz
90%
88%
86%
84%
82%
80%
78%
76%
74%
72%
70%
0
12
24
36
48
60
ILED (mA)
C002
Top to Bottom: 3x3, 3x4, 3x5, 3x6, 3x7 (LEDs)
Figure 35. Boost Efficiency vs I_LED
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