Data Sheet

2

Rev. 1.2, 2004-04-13

TLE 4241 GM

Circuit Description

Figure 1

Block Diagram

An internal reference voltage of typ. 1.20 V supplies the REF pin which is connected to

GND via an external resistor. In the SET = H mode the reference current flowing on the

REF pin is mirrored with an amplification to form the desired output current. The typ.

output current in the SET = H mode calculates:

(1)

The output current is shown as a function of the reference resistance on Page 10 for the

high as well as for the low current mode.

With the PWM input the LED brightness can be regulated via duty cycle. Also PWM = L

sets the TLE 4241 in sleep mode resulting in a very low current consumption of << 1

µA

typ. Due to the high impedance of the PWM input (see timing diagram

I

on Page 12) the PWM pin can thus also be used as an Enable input.

AEB03003

Regulation

High

Regulation

Low

Reference

Voltage

Q

REF

SET

PWM

ST

I

GND

,

/mA

1.20

----------------------

487

0.1

+

×

=