ICLS6022J Datasheet, PDF (20/33 Pages) Infineon Technologies AG – LED System Driver ICs

LED System Driver ICs
ICLS6x Series
Functional Description
Extremely precise current limiting is now possible.
For example, I_peak = 0.5 A with R_Sense = 2 Ω. Without propagation delay compensation the current sense threshold
is set to a static voltage level V_csth = 1 V. A current ramp of dI/dt = 0.4 A/µs (that means, dV_Sense/dt = 0.8 V/µs),
and a propagation delay time t_{Propagation Delay} = 180 ns then leads to an I_peak overshoot of 14.4 %. With propagation
delay compensation the overshoot is only about 2 % (see Figure 13).
V
1, 3
1, 25
1, 2
1, 15
1, 1
1, 05
1
0, 95
0, 9
0
with com pensation
without com pensation
0,2 0, 4 0, 6 0, 8
1 1, 2 1, 4 1,6 1,8
dV_Sense
dt
2_V
μs
Figure 13 Overcurrent shutdown
Propagation delay compensation is realized by means of a dynamic threshold voltage V_csth (see Figure 14). If the
slope is steeper, driver switch-off takes place earlier to compensate for the delay.
VOSC _{max. Duty Cycle}
V Sense
V_csth
off time
Propagation Delay t
Signal1
Figure 14 Dynamic voltage threshold V_csth
Signal2
t
Data Sheet
20
Version 1.0, 2011-05-19