TLD5085EJ.PDF

Infineon ® Power LED Driver

TLD5085EJ

1.8A DC/DC Step-Down Converter

Datasheet

Rev. 1.1, 2009-12-16

Automotive Power

1.8A DC/DC Step-Down Converter

TLD5085EJ

Overview

• Wide Input Voltage Range from 4.75V to 45V

• Constant Current or Constant Voltage Regulation

• Drives LEDs in Buck Topology

• Very low shutdown current consumption (typ. 0.1µA)

• 370 kHz switching frequency

•PWM Dimmig

• Integrated power-switch (output current up to 1.8A)

• Internal Soft-Start function

• ± 2% output current tolerance (± 4% for full load current range)

• Small thermally enhanced exposed heatslug package

• Over Temperature Shutdown

• AEC Qualified

• Green Product (RoHS Compliant)

PG-DSO-8 (e-Pad)

Description

The TLD5085EJ is a smart LED buck converter with an integrated power-switch, capable of driving up to 1.8A load

current with excellent line and load regulation. The main function of this device is to step-down the input voltage

and regulating a constant LED current. The constant current regulation is especially beneficial for LED color

accuracy and longer lifetime. The TLD5085EJ also has a PWM input which can be used for LED dimming. The

switching frequency of 370kHz allows to use small and inexpensive passive components. An Enable function is

implemented to reduce the shut-down current consumption to typ. 0.1µA. This IC is suited for use in the harsh

automotive environments and provides protection functions such as current limitation and overtemperature

shutdown. The integrated soft-start feature avoids a current and voltage overshot at the output during start-up of

the device.

Applications

• Automotive Lighting (Reading Light, Dome Light, Dashboard Backlighting)

• High Power LED Applications

• Constant Current and Voltage Source

Type

Package

Marking

TLD5085EJ

PG-DSO-8 (e-Pad)

TLD5085

Datasheet

Rev. 1.1, 2009-12-16

TLD5085EJ

Block Diagram

Enable

Charge Pump

Over

Temperature

Shutdown

BDS

Feedforward

COMP

Buck

Converter

BUO

PWMI

Oscillator

Bandgap

Reference

Soft start ramp

generator

TLD5085

GND

Figure 1

Block Diagram

Datasheet

Rev. 1.1, 2009-12-16

TLD5085EJ

Pin Configuration

3.1

Pin Assignment

PWMI

TLD5085

GND

COMP

BUO

BDS

S 08_ Pinout _TLD5085 .vsd

Figure 2

Pin Configuration

3.2

Pin Definitions and Functions

Pin Symbol Function

1 I PWM Input for;

Provides LED dimming option. If not used connect to VS.

2 D Ground;

Connect to system ground.

3 COMP Compensation Input;

Frequency compensation for regulation loop stability.

Connect R and C network to pin for stability.

4 B Feedback Input;

Connect a defined power resistor (RFB=0.6V/ILED) to get the needed LED output current.

For adjustable output voltages connect this pin via a voltage divider in parallel to the output

capacitor.

5 S Buck Driver Supply Input;

Connect the bootstrap capacitor between this pin and pin BUO.

6 O Buck Switch Output;

Source of the integrated power-switch. Connect directly to the cathode of external freewheeling

diode and the buck circuit inductance.

7 N Enable Input;

Apply logic high signal to enable the device. A pull down resistor is integrated.

8 S Supply Voltage Input;

Connect to supply voltage source.

Exposed Pad;

Connect to heatsink area and GND by low inductance wiring.

Datasheet

Rev. 1.1, 2009-12-16

TLD5085EJ

General Product Characteristics

4.1

Absolute Maximum Ratings

Absolute Maximum Ratings 1)

T j = -40 ° C to +150 ° C; all voltages with respect to ground (unless otherwise specified)

Pos.

Parameter

Symbol

Limit Values

Unit Conditions

Min.

Max.

Voltages

4.1.1

PWMI (Pin1)

PWM Input

V PWMI

-0.3

–

4.1.2

COMP (Pin 3)

Compensation Input

V COMP

-0.3

5.5

–

4.1.3

6.2

t < 10s 2)

4.1.4

FB (Pin 4)

Feedback Input

V FB

-0.3

5.5

–

4.1.5

BDS (Pin 5)

Buck Driver Supply Input

V BDS V BUO

- 0.3

V BUO

+ 5.5

V–

4.1.6

BUO (Pin 6)

Buck Switch Output

V BUO

-2.0

V VS + 0.3 V

–

4.1.7

EN (Pin 7)

Enable Input

V EN

-40

–

4.1.8

VS (Pin 8)

Supply Voltage Input

V S

-0.3

–

Temperatures

4.1.9

Junction Temperature

T j

-40

150

° C–

4.1.10

Storage Temperature

T stg

-55

150

° C–

ESD Susceptibility

4.1.11

ESD Resistivity all Pins to GND

V ESD

-2

HBM 3)

1) Not subject to production test, specified by design

2) Exposure to those absolute maximum ratings for extended periods of time ( t > 10s) may affect device reliability

3) ESD susceptibility HBM according to EIA/JESD 22-A 114B (1.5k Ω ,100pF).

Note: Stresses above the ones listed here may cause permanent damage to the device. Exposure to absolute

maximum rating conditions for extended periods may affect device reliability.

Note: Integrated protection functions are designed to prevent IC destruction under fault conditions described in the

data sheet. Fault conditions are considered as “outside” normal operating range. Protection functions are

not designed for continuous repetitive operation.

Datasheet

Rev. 1.1, 2009-12-16

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