TLD1326EL_15 Datasheet, PDF (20/34 Pages) Infineon Technologies AG – 3 Channel High Side Current Source

TLD1326EL
8
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
VIN_SET
VIN_SET(N-1)
GND
Figure 12 Block Diagram IN_SET pin
8.1
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
(10)
The gain factor k (R_SET * output current) is specified in Pos. 10.2.4 and Pos. 10.2.5. 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.
8.2
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 13. 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 15 for details. In addition, the IN_SET pin offers the
diagnostic feedback information. In case of a fault event the IN_SET voltage is increased to V_{IN_SET(N-1)} Pos. 9.3.2.
Therefore, the device has two voltage domains at the IN_SET-pin, which is shown in Figure 16.
Microcontroller
(e.g. XC866)
OUT ^RSET/2
R_SET/2
IN_SET
Current
adjust
IN
V_DDP = 5 V
Figure 13 Schematics IN_SET interface to µC
Basic LED Driver
Data Sheet
20
GND
Rev. 1.1, 2015-03-24