TLE4241GM_15 Datasheet, PDF (4/15 Pages) Infineon Technologies AG – Adjustable Current LITIX™ Linear

TLE4241GM
Application Information
WD R
V_Q
µC
10 kΩ
W
RO
TLE 4271
22 µF
ST
I
PWM
SET ^{TLE 4241G Q}
R_REF
V_Batt
100 nF
LA E67B
OSRAM
AED03098
Figure 3 Application Circuit
Figure 3 shows a typical application with the TLE4241GM LITIX^TM Linear. The 3 LEDs
are driven with an adequate supply current adjusted by the resistor R_REF. Thus
brightness variations due to forward voltage spread of the LEDs are prevented. The
luminosity spread arising from the LED production process can be compensated via
software by an appropriate duty cycle applied to the PWM pin. Hence selection of the
LEDs to forward voltage as well as to luminosity classes can be spared. The slightly
negative temperature coefficient of the TLE4241GM output current protects the LEDs
against over-temperature stress if the IC is placed nearby the LEDs.
The voltage drop (V_I - V_Q) across the TLE4241GM is monitored in order to detect an
open load condition indicated at the status output pin ST. In case of open load, the
voltage drop will decrease below the lower status switching threshold V_dr,L. Hence, the
status output ST will be driven low. In normal operation, the voltage drop is above the
upper status threshold V_dr,H, thus the open collector output ST is in high-ohmic state (see
also section Status Output at the Electrical Characteristics).
The function of ST, SET and PWM as well as their timings are shown in Figure 4.
Data Sheet
4
Rev. 1.4, 2015-10-05