Other Parts Discussed in Thread: LM3410, TPS92692, TPS92691
I am currently using the LM3410-Q to drive a Bridgelux COB Gen 8 V8, 17.5V @ 1A output. This is being used in an underwater video light.
It works fine for awhile with a freshly charged battery (8.2V for a six cell NiMH pack). As the battery runs down it starts blinking. At first I thought it was the 3410 overheating. But after much testing it appears that the current limit is being hit. In the table it shows the current limit between 2.1 and 2.8 AMPS. I thought I would be OK since the output current in my design is 1 amp. Turns out that current spec on the data sheet is for the input current. On the surface it works reasonably well but put the circuit in an enclosure and it does not run nearly as long. It starts blinking as the battery runs down. Of course as the battery runs down the input current goes up and hits the current limit. Though it is not mentioned in the datasheet, it appears that as the LM3410 ambient temperature goes up, the current limit goes down. So as the temperature inside the enclosure goes up, the current limit goes down and it starts blinking. It does not get up to 165° C for the 3410 to go into thermal shutdown. So it looks like it is a current limit that is temp. dependent. My next step is to pursue heat sink modifications.
If I run the above setup at .7 amps output, it works just fine
So my question is, does TI have a driver that is more suitable for my application? Input is 7.2 - 8.2V and output is 17.5 @ 1 amp.
Best regards,
Roger
