| ??? 08/16/08 21:10 Read: times |
#157516 - that's why they make logic MOSFET's Responding to: ???'s previous message |
The IRLD120, for example has a minimal Vgs of 1 volt and a maximum a 250 uA and Vgs=Vds. By the time Vgs gets up to 3 volts, the MOSFET is ON. Its RdsON is 0.27 ohms at Vgs=5 volts. This is one of the poorer logic MOSFETs of this sort, yet should work just fine. It certainly works fine for me. There are many, much more modern logic level MOSFETs that switch at lower Vgs and have an order of magnitude lower RdsON when the Vgs exceeds the threshold voltage by a volt or more.
The reason I like the N-channel parts is because they're more plentiful. The only "gotcha" is that you have to drive them trough an inverter, as the MCU, being slow to wake up and initialize, comes up with the port pin high, and, even with small pulldown current from its gate, the MOSFET can momentarily be ON. An inverter fixes that. RE |
| Topic | Author | Date |
| How to turn on/off another MCU | 01/01/70 00:00 | |
| Low-power mode? | 01/01/70 00:00 | |
| not a power consumption issue | 01/01/70 00:00 | |
| correction | 01/01/70 00:00 | |
| Logic MOSFET | 01/01/70 00:00 | |
| P-Channel Enhancement Mode Better | 01/01/70 00:00 | |
| that's why they make logic MOSFET's | 01/01/70 00:00 | |
| Makes No Difference | 01/01/70 00:00 | |
| Perhaps you should try a logic-MOSFET | 01/01/70 00:00 | |
| It Still Makes No Difference | 01/01/70 00:00 | |
| Maybe it's the load current | 01/01/70 00:00 | |
| Richard........................... | 01/01/70 00:00 | |
| I wouldn't say that ... | 01/01/70 00:00 | |
| possibly simpler idea | 01/01/70 00:00 | |
Thank you all, | 01/01/70 00:00 |