TLD5098EL Infineon Technologies, TLD5098EL Datasheet - Page 27

• Manufacturer Part Number: TLD5098EL
• Description: IC DC-DC CTRLR BUCK BOOST 14SSOP
• Manufacturer: Infineon Technologies

Specifications of TLD5098EL

• Constant Current: Yes
• Constant Voltage: Yes
• Internal Driver: No
• Type - Primary: Automotive
• Mounting Type: Surface Mount
• Topology: PWM, SEPIC, Step-Down (Buck), Step-Up (Boost)
• Number Of Outputs: 1
• Frequency: 100kHz ~ 500kHz
• Voltage - Supply: 4.5 V ~ 45 V
• Voltage - Output: 4.5 V ~ 5.5 V
• Package / Case: 14-LSSOP (0.150", 3.95mm Width) Exposed Pad
• Packages: PG-SSOP-14
• Vs (min): 4.75 V
• Vs (max): 45.0 V
• Vq (max): -
• Iq (max): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Lead Free Status / Rohs Status: Details

10
This pin is influencing the Feedback Voltage Error Amplifier by generating an internal current accordingly to an
external reference voltage (V
or external > 1.6V supply. Different application scenarios are described in
of the ECU for instance if a thermistor is connected on a separated LED Module and the Analog Dimming Input is
used to thermally protect the LEDs. For reverse battery protection of this pin an external series resistor should be
placed to limit the current.
10.1
1) It is difficult for LED manufacturers to deliver LEDs which have the same Brightness, Colorpoint and Forward
Voltage Class. Due to this relatively wide spread of the crucial LED parameters automotive customers order LEDs
from one or maximum two different colorpoint classes. The LED manufacturer must preselect the LEDs to deliver
the requested colorpoint class. Those preselected LEDs are matched in terms of the colorpoint but a variation of
the brightness remains. To correct the brightness deviation an analog dimming feature is needed. The mean LED
current can be adjusted by applying an external voltage V
2) If the DC/DC application is separated from the LED loads the ECU manufacturers aim is to develop one
hardware which should be able to handle different load current conditions (e.g. 80mA to 400mA) to cover different
applications. To achieve this average LED current adjustment the analog dimming is a crucial feature.
10.2
Application Example:
Desired LED current = 400mA. For the calculation of the correct Feedback Resistor R
be used: This formula is valid if the analog dimming feature is disabled and V
A decrease of the average LED current can be achieved by controlling the voltage at the SET pin (V
0V and 1.6V. The mathematical relation is given in the formula below:
If V
example I
Datasheet
SET
is 100mV the LED current is only determined by the internal offset voltages of the comparators. For this
LED
Analog Dimming
Purpose of Analog Dimming:
Description
= 0A if V
SET
I
LED
<
100mV. Refer to the concept drawing in
=
SET
V
R
). If the analog dimming feature is not needed this pin must be connected to IVCC
REF
FB
I
-->
LED
R
FB
=
=
V
I
V
REF
LED
SET
27
5
-->
SET
*
R
−
at the SET pin.
R
FB
0
FB
=
1 ,
Figure
400
0
V
3 .
mA
V
Figure
17.
SET
=
750
> 1.6V.
18. This pin can also go outside
m
FB
Ω
the following equation can
Rev. 1.0, 2010-10-13
Analog Dimming
TLD5098EL
SET
) between