ILED = GainTORCH/FLASH

VA

1.3V

RA

1.3V

RSET

Copyright © 2016, Texas Instruments Incorporated

LM2758

ISET

PGND SGND

EN1

EN2

VIN

2.2 µF

C1

+

C2

+

C2

-

C1

-

1 µF

1 µF

2.2 µF

CPOUT

LED-

+

-

RSET

RA

VA

CIN

C1

C2

COUT

9

LM2758

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SNVS551E – APRIL 2008 – REVISED MAY 2016

Product Folder Links: LM2758

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Feature Description (continued)

7.3.6 Analog Brightness Control

Figure 7. Analog Brightness Control

The current through the LED can be varied dynamically by changing the ISET current. Figure 7 shows the circuit.

The current though the LED can be calculated with Equation 2:

(2)

7.3.7 Thermal Protection

Internal thermal protection circuitry disables the LM2758 when the junction temperature exceeds 150°C (typical).

This feature protects the device from being damaged by high die temperatures that might otherwise result from

excessive power dissipation. The device recovers and operates normally when the junction temperature falls

below 140°C (typical). It is important that the board layout provide good thermal conduction to keep the junction

temperature within the specified operating ratings.