DER286 might be the another good design example using LinkSwitch-PH for the high power LED driver application.

The functional description of LinkSwitch-PH in the datasheet and the application not, AN-49, explain how to design LED driver using LinkSwitch-PH.

The LinkSwitch-PH is the constant current controll device (CC) with the given LED voltage, and the output current is controlled by the sensed input voltage (Iv) and the reflected output voltage (Ifb).

I looked at the DER286 and it looks prety good. I just need to reduce the output voltage to around 12.3V and increase the current to 1.75Amp. how will I go about this. This is for a non-dimming application.
1. According to the description of the feedback pin is that the current into this pin is directly proportional to the output voltage. Is this correct?
2. Except for the output power level determined by the capacitor on the BP pin. is there any way to fix the output current?
3. On page 7 of the LNK403-409/413-419 family dataheet it ismentioned that "The VOLTAGE MONITORING pin current and the FEEDBACK pin current are used internally to control the average output LED current." In what way? how do we fix/determine the output current. In our product we need 1.75A.

1. The feedback current represents the output voltage to control the output current.

2. The capacitor on the BP pin determines the current gain, and the output current is determined by the feedback current and the voltage monintoring pin, Vpin, current.

3.Attached is the PIXL result for the universal input, 12.3V_1.75A LED driver using LNK416EG. There are all necessary design parameters available in the PIXL result.

Thanks. How will the power factor be influenced by these changes?

Not much.

The power factor will be mostly influenced by the KP factor, which determines the continuous design.

Will the power factor go down or up.
Please pardon my ignorance... What is the KP factor?

Don't bother, I found what it is.
1. "Ripple to Peak Current Ratio" Does this mean the Ripple amplitude?
2. How would this influence the power factor? Is there a positive gradient linear relationship. i.e. does the power factor increase with increasing KP or is it vice versa?

The input current waveshape of the LED driver using LinkSwitch-PH depends on the mode operation, continous or discontinous mode.

As the KP value is lower (KP< 1), continuous mode operation, the input current is shape is sinusoidal.

As the KP value is higher (KP>1), discontinuous mode operation, the input current shape is getting rectangular, and the power factor is lower.

Thanks.
1. What circuit diagram does the resistor values in the designe sofrware refer to?
2. The PIExpert software works well on my Windows XP but does not work when installing it on my Windows 7 - 32 Bit. What can I do?

We have tested the software on Windows 7 (both 32 bit and 64 bit versions). So there must be either something in your regional settings or just a corrupt installation file.
Can you re-install and try again? Version 8.6 is now available from the website for a fresh installation.

There are two resistors in the CC compensated for input voltage variation block in the attached circuit details. The top one is the VR1, and the resistor between Vpin and source pin is the VR2.

There are two resistors in the Output LED voltage feedback block in the attached circuit details. The resistor between bias voltage and FB pin is the RFB1, and the resistor between FB pin and source pin is the RFB2

There are two resistors in the CC compensated for input voltage variation block in the attached circuit details. The top one is the VR1, and the resistor between Vpin and source pin is the VR2.

There are two resistors in the Output LED voltage feedback block in the attached circuit details. The resistor between bias voltage and FB pin is the RFB1, and the resistor between FB pin and source pin is the RFB2

Thanks a lot. I downloaded the 8.6 version, installed it and it works 100%. Thanks