| ??? 04/09/08 13:29 Read: times |
#153052 - Hhm... Responding to: ???'s previous message |
Erik said:
An ideal constant Current Source has a resistance of zero ohms and that makes T = RC very small. According to R = dU / dI, an ideal current source shows an infinitely high source resistance. Why? Because an ideal current source allows huge dU while regulating dI to zero, making R infinitely high. An ideal voltage source, on the other hand, allows huge dI while regulating dU to zero, making R to zero. By the way, take care that the pull-ups does not decrease too much. The I2C bus can be extended over a larger area. Too fast rise and fall times would be problematic because of transmission line effects like ringing, overshots and phase margin violations. Kai |
| Topic | Author | Date |
| I2C pullup requirements | 01/01/70 00:00 | |
| Multi master | 01/01/70 00:00 | |
| Pull-up is needed | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Confirm pullup needed | 01/01/70 00:00 | |
| correct all | 01/01/70 00:00 | |
| It depends | 01/01/70 00:00 | |
| not just that | 01/01/70 00:00 | |
| I2C R pull ups Requements | 01/01/70 00:00 | |
| Or use a constant Current Source | 01/01/70 00:00 | |
| and a good one if it is .. | 01/01/70 00:00 | |
| Hhm... | 01/01/70 00:00 | |
| Extend over a distance... | 01/01/70 00:00 | |
Thanks for this informative reply! | 01/01/70 00:00 | |
| OK | 01/01/70 00:00 |