Is the LM3431 capable of delivering 750mA - 1,000mA to each of the three independant LED strings?
Several months ago I was trying to decide what IC I was going to use for an upcoming project (design parameters below) and I thought that I had settled on using the LM3431. Coming back to the project now, I'm not sure that I have made the correct choice, please correct me where I am wrong or advise any alternative solutions :)
Input Voltage: 10 - 25V (DC) Battery pack design still has some flexibility
Output: ~30 WLEDs (preferably in 3 or 4 separate strings) *Cree XBD WLEDs - 700 - 1,000mA drive current, Max. Vf = 3.5V (typically 3.2V - 3.3V)
- 35V (max) @ 1,000mA (max) x 3-strings....... 30x WLEDs total
or - 28V (max) @ 1,000mA (max) x 4-strings....... 32x WLEDs total
If I use NFETs instead of NPN transistors (perhaps CSD18501's) for the current regulators on NDRV1, NDRV2, NDRV3, will the LM3431 be able to handle the desired LED string currents of 1,000mA??
I am also planning on using the same type NFET for the boost switcher (LG pin)
is there anything else that I need to give further attention to?
any help/advice appreciated
