FP7103 datasheet(8/12 Pages) FEELING

8 / 12 page

FP7103

This datasheet contains new product information.

Feeling Technology reserves the rights to modify the product specification without notice.

No liability is assumed as a result of the use of this product. No rights under any patent accompany the sales of the product.

Website: http://www.feeling-tech.com.tw

Rev. 0.94

8/12

Detailed Description

Voltage Reference

A built-in 2.5V reference regulator supplies FP7103 internal circuits. Also, this 2.5V reference

voltage is divided down by an internal resistive divider to provide a 0.25V precision reference voltage to

the error amplifier non-inverting terminal.

Setting the LED Current

FP7103 is a constant current buck regulator. The LEDs are connected between VOUT and FB pin

as shown in the Typical Application Circuit section. The FB pin is 0.25V in regulation. Therefore, the

LEDs current IF is set by VFB and the resistor R2 connected between FB and ground by the following

equation:



IF should not exceed the 3A current capability of FP7103 and therefore R2 minimum must be

approximately 0.083

Output Voltage

The output voltage is primarily determined by the number of LEDs(n) connected between VOUT

and FB pin. Therefore, VOUT can be written as:

)

((

OUT







Where VF is the forward voltage of one LED at the set LED current level (see LED manufacturer

datasheet for forward characteristics curve)

Oscillator

The fixed PWM frequency is generated by an internal oscillator. Its typical values are 320KHz.

Thermal Protection

The thermal protection is triggered when junction temperature is higher than 150

℃ that may

occurs by an abnormal heavy current loading. When this happens, the FP7103 turns output off. Once

the junction temperature is cooled down to lower than 130

℃, FP7103 starts again and turns the power

switch on.

FP7103 데이터시트(PDF) 8 Page - Feeling Technology Corp.