TLD1313EL Datasheet, PDF (15/31 Pages) Infineon Technologies AG – 3 Channel High Side Current Source Basic LED Driver

TLD1313EL
6
IN_SET Pin
The IN_SET pin is a multiple function pin for output current definition, input and diagnostics:
IN_SET Pin
Logic
IN_SET
IIN_SET
high impedance
VIN_SET
VIN_SET(OL /SC)
GND
Figure 7 Block Diagram IN_SET pin
6.1
Output Current Adjustment via RSET
The output current for all three channels can only be adjusted simultaneously. The current adjustment can be done
by placing a low power resistor (R_SET) at the IN_SET pin to ground. The dimensioning of the resistor can be done
using the formula below:
R_SET
=
-----^k------
I_OUT
(2)
The gain factor k (R_SET * output current) is specified in Pos. 9.2.4 and Pos. 9.2.5. The current through the R_SET is
defined by the resistor itself and the reference voltage V_{IN_SET(ref)}, which is applied to the IN_SET during supplied
device.
6.2
Smart Input Pin
The IN_SET pin can be connected via R_SET to the open-drain output of a µC or to an external NMOS transistor as
described in Figure 8. This signal can be used to turn off the output stages of the IC. A minimum IN_SET current
of I_{IN_SET(act)} is required to turn on the output stages. This feature is implemented to prevent glimming of LEDs
caused by leakage currents on the IN_SET pin, see Figure 11 for details. In addition, the IN_SET pin offers the
diagnostic feedback information, if the status pin is connected to GND. Another diagnostic possibility is shown in
Figure 9, where the diagnosis information is provided via the ST pin (refer to Chapter 7 and Chapter 8) to a micro
controller. In case of a fault event with the ST pin connected to GND the IN_SET voltage is increased to
V_{IN_SET(OL/SC)} Pos. 8.4.2. Therefore, the device has two voltage domains at the IN_SET-pin, which is shown in
Figure 12.
Data Sheet
15
Rev. 1.0, 2013-08-08