CAT3644 Datasheet, PDF (4/14 Pages) Catalyst Semiconductor – 4-Channel Ultra High Efficiency Quad-Mode TM LED Driver

CAT3644
Table 4. RECOMMENDED EN/DIM TIMING
(For 2.4 V ≤ V_IN ≤ 5.5 V, over full ambient temperature range −40°C to +85°C.)
Symbol
Name
Conditions
T_SETUP
T_LO
T_HI
T_PWRDWN
T_LED
EN/DIM setup from shutdown
EN/DIM program low time
EN/DIM program high time
EN/DIM low time to shutdown
LED current settling time
T_SETUP
T_HI
Min
Typ
Max
Units
10
ms
0.2
100
ms
0.2
ms
1.5
ms
40
ms
T_PWRDWN
EN/DIM
T_LED
LED
Current
Shutdown
100%
T_LO
100%
50%
25% _{12.5% 6.25% 3.12%}
Figure 2. EN/DIM Digital Dimming Timing Diagram
LED Current Setting
The nominal LED current is set by the external resistor
connected between the RSET pin and ground. Table 5 lists
standard resistor values for several LED current settings.
Table 5. RESISTOR RSET AND LED CURRENT
LED Current (mA)
RSET (kW)
2
40.0
5
15.8
10
7.87
15
5.23
20
4.02
25
3.16
30
2.67
Shutdown
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