Ver3.0

13

LD1510

3Channel Output LED Driver with 12 bit PWM Controller

LED SUPPLY VOLTAGE( VLED )

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V

LED

Vf

LD1510

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V

LED

Vf

LD1510

It is very important to select the proper value of Load Resistor( RL ). Because the optimal VOUT value

guarantees the constant output current and long life time of LED driver IC without over power consumption.

For example, let’s calculate the Load Resistor value at VLED=12V, Iout=50mA, LED Forward Voltage(Vf)=3V.

1) The full current of LD1510 = 50mA x 3 (channels) = 150mA

2) The power consumption is 150mA x VOUT voltage.

- when VOUT = 1V, the power consumption is 150mW.

- when VOUT= 2V, the power consumption is 300mW.

Therefore, the Load Resistor (RL) = (VLED – VOUT– Vf*3) / Iout

= (12V –VOUT –9V) / 50mA

= 40Ω (When VOUT = 1V)

Vf

Vf

Vf

Vf