| ??? 07/19/05 20:41 Modified: 07/19/05 20:51 Read: times |
#97647 - I drive optoisolators directly from port Responding to: ???'s previous message |
Current plan:
Port pin ----> PNP transistor -----> optoisolator ----> high-side driver ----> N-channel MOSFET I drive optoisolators directly from port pins. The diode on some/most does not require more current than a port pin can sink. e.g. the PS2705 that I use works just fine with 5 mA. Of course, to do this you will need to use a '51 that can deliver more than the measly 25mA the Dallas chip allow you. The lowly LPC93x chips will do a total of 80mA, the P89C51Rx2 has no package limitation but the max power just 15mA per pin. I never caought on to the fact that Dallas only allow measly currents, but then, I have not used them often. Erik |
| Topic | Author | Date |
| Parts count when driving many MOSFETs | 01/01/70 00:00 | |
| Logic Level MOSFET? | 01/01/70 00:00 | |
| Reducing parts count with many MOSFETs | 01/01/70 00:00 | |
| Much more information needed | 01/01/70 00:00 | |
| Reducing parts count | 01/01/70 00:00 | |
| Automotive drivers | 01/01/70 00:00 | |
| Mosfet driver | 01/01/70 00:00 | |
| I drive optoisolators directly from port | 01/01/70 00:00 | |
| digital optos | 01/01/70 00:00 | |
| parts count | 01/01/70 00:00 | |
Simply | 01/01/70 00:00 |