ZHCU740 April 2020
Choosing LED capacitor is very important when it comes to rise times, delay times, and current ripple. Here is a table what capacitor measurements that we made to help choose proper capacitor based on rise time and current ripple requirements. Capacitor choice might be different for Blue vs. Green LEDs. Green and top side pump are placed in parallel and are a larger load to the driver compared to just a Blue LED by itself.
| COLOR | CAP (UF) | ENABLE DELAY (US) | RISE TIME (US) | ENABLE DELAY + RISE TIME | RIPPLE PEAK TO PEAK (A) |
|---|---|---|---|---|---|
| Green | 6.60 | 16.70 | 4.30 | 21.00 | 0.60 |
| Green | 4.40 | 12.40 | 4.40 | 16.80 | 0.80 |
| Green | 3.30 | 7.00 | 3.00 | 10.00 | 1.00 |
| Green | 2.20 | 6.50 | 2.70 | 9.20 | 0.60 |
| Blue | 10.0 | 11.20 | 3.60 | 14.80 | 0.64 |
| Blue | 6.60 | 11.50 | 4.80 | 16.30 | 0.56 |
| Blue | 4.40 | 8.70 | 3.40 | 12.10 | 0.72 |
| Blue | 3.30 | 5.50 | 3.30 | 8.80 | 0.60 |
| Blue | 2.20 | 4.00 | 1.90 | 5.90 | 0.56 |