Regarding LED7707 based design

[kiran23]

Posted on June 10, 2010 at 13:52

One of our client facing following problems.

                They want to use the LED7707 for Solar Lantern application.  their output will be 3Nos of 1W LED string for which they need constant current output of 150mA. But their Board is not working.  

1. They  shorted the Rows with connecting wires by soldering.  Will this affect the IC?

2. The output is  connected to V boost and GND.

3.What to do with SW1 and SW2?

They  want it to work with a 6VBattery.

That is they will be giving a input voltage from 4.5V to about 7.5V.

The circuit that they  want to build up is attached .

Pls Reply ASAP.

[mallik.ranajay]

Posted on June 16, 2010 at 10:47

Hi,

What is the status of the DIM pin? Is it fed with a PWM or is it floating? Is the device oscillating at all? Have you seen the Lx pin waveform? What are the values of the RILIM and BILIM resistors? Is the inductor having suitable Isat rating? Peak currents can be high. Regards, Ranajay