EC4101-G datasheet(4/6 Pages) ETC2

4 / 6 page

Four Channel Constant Current LED Driver

EC4101

ISET Pin

The ISET pin is the servo point of an amplifier configured as a voltage to current converter. The voltage at

this pins servos to the internal bandgap potential. A set resistor can be connected from the Iset pin to

ground to generate a reference current for the following current gain stages. A current could alternately be

applied to this pin in the form of a current source or current output DAC. This pin can also have a PWM

signal applied to control the LED brightness.

The RSET value may be determined as RSET = 1.5 * 1200/IOUT, kΩ where 1.5 is a typical ISET pin voltage,

1200 is a typical current multiplication ratio, and IOUT is a required LED current in mA.

Cathode Voltage, Supply Voltage and Power Dissipation

The voltage applied to the cathode of each LED determines the overall efficiency of the EC4101 circuit.

The EC4101 is designed to be able to sink 125mA at each of its four outputs; LED1 - 4. The EC4101 is

also designed to be able to handle up to 18V on these pins. This voltage handling capability assumes the

total power can be dissipated by the EC4101. The power dissipation inside the EC4101 will de directly

related to the voltage and current applied to these pins. For example, the typical operating cathode voltage

is 500mV. At maximum current the power dissipated by one LED driver output is 125mA * 500mV =

62.5mW. The following charts show the power dissipation of the EC4101 under various conditions. The

power dissipation should be kept below 1.3W for safe operation and long term reliability at room

P 4 / 6

DR18EC070105-VER1.0

EC4101-G Datasheet(PDF) 4 Page - List of Unclassifed Manufacturers