spencer
Enlightened
I am looking for a driver that needs to have the following:
- run off of an automotive system (14.4v - 8vish)
- 1A - low mA variable output
- have dimming with the use of a potentiometer
- The ability to drive 30 LEDs (I know I won't find this so either few boost or many buck)
- fairly high efficiency (85%+)
I was originally thinking about the CCHIPO driver but was wondering if there was a cheaper option. I would have used 3 of them to drive 10 LEDs each. I was playing around with National's WebBench tool and have come up with some options but none of them have dimming (it may be able to add a pot somewhere in the circuit but I don't know how) and most of them have a duty cyle of around 33% at 14.4v. These would be used in an offroad light so 33% might not be enough.
A solution from National would be an option for me if it can be adapted. I have the ability to solder all of the surface mount parts they suggest and I can get the PCB made.
The solution I came up with from them would drive 6 LEDs so I would have to use 5 of them but they are only about $13 each so that is definately cheaper than 3 CCHIPOs. Any way I drive them I want each driver to drive the same amount of LEDs (ex. 3 boost driving 10 each, 5 boost driving 6 each, 6 boost driving 5, 10 buck/boost driving 3, 15 buck driving 2).
Also, all the drivers have to be connected to the same pot. The more drivers I have the weirder it will get trying to get them all on the same pot.
Finally, what considerations have to be taken when using a dirty automotive supply. I have heard that some systems have spikes of 30 some volts. Maybe put a diode or something before the driver to prevent anything over 15V in?
Thanks,
Spencer
- run off of an automotive system (14.4v - 8vish)
- 1A - low mA variable output
- have dimming with the use of a potentiometer
- The ability to drive 30 LEDs (I know I won't find this so either few boost or many buck)
- fairly high efficiency (85%+)
I was originally thinking about the CCHIPO driver but was wondering if there was a cheaper option. I would have used 3 of them to drive 10 LEDs each. I was playing around with National's WebBench tool and have come up with some options but none of them have dimming (it may be able to add a pot somewhere in the circuit but I don't know how) and most of them have a duty cyle of around 33% at 14.4v. These would be used in an offroad light so 33% might not be enough.
A solution from National would be an option for me if it can be adapted. I have the ability to solder all of the surface mount parts they suggest and I can get the PCB made.
The solution I came up with from them would drive 6 LEDs so I would have to use 5 of them but they are only about $13 each so that is definately cheaper than 3 CCHIPOs. Any way I drive them I want each driver to drive the same amount of LEDs (ex. 3 boost driving 10 each, 5 boost driving 6 each, 6 boost driving 5, 10 buck/boost driving 3, 15 buck driving 2).
Also, all the drivers have to be connected to the same pot. The more drivers I have the weirder it will get trying to get them all on the same pot.
Finally, what considerations have to be taken when using a dirty automotive supply. I have heard that some systems have spikes of 30 some volts. Maybe put a diode or something before the driver to prevent anything over 15V in?
Thanks,
Spencer
