| ??? 01/13/10 05:58 Read: times |
#172408 - driving a triac with a ATMEL MCU |
AT89C4051 or AT89LP4052? turning on and off a sensitive gate triac. The triac is rated at 3 mA gate current Vgt = 2V.
Has anyone tried to drive the gate of a small triac directly with the port pin of the above MCU? Series gate resistor around 600 Ohms. The ATMEL chip can sink up to 10 mA per port pin but can source only 60 uA. Do I need a buffer IC of some sort or can I save on parts count and simply use a series gate resistor? The reason I am asking is the previous person who did this for the company asking me to take over this design project did it with PIC microcontrollers. I don't have the time on this project to learn to speak PIC and would like to do it with 8051 core MCU's instead. And the new PC board won't fit into the tiny space allowed for the design if I have to add a buffer gate for each of the 8 tiny triacs. What am I missing? Am I getting hung up on sourcing current (3 mA) through the MCU port pin when I should only be concerned about the gate voltage needed? How does the gate of the triac get it's 3 mA of gate current if it is not through the port pin of the MCU? |
| Topic | Author | Date |
| driving a triac with a ATMEL MCU | 01/01/70 00:00 | |
| pull-up or other chip? | 01/01/70 00:00 | |
| probably | 01/01/70 00:00 | |
| five volts controlling a hundred | 01/01/70 00:00 | |
| so i answered | 01/01/70 00:00 | |
| Throwing out the baby? | 01/01/70 00:00 | |
| previous | 01/01/70 00:00 | |
| they need freelancers? | 01/01/70 00:00 | |
| I see | 01/01/70 00:00 | |
| Yep | 01/01/70 00:00 | |
| don't forget about "triac drivers" | 01/01/70 00:00 | |
| my prefered way | 01/01/70 00:00 | |
| Do always use a buffer! | 01/01/70 00:00 | |
| there is an old Philips appnote which ... | 01/01/70 00:00 | |
| incredible | 01/01/70 00:00 | |
Thanks! | 01/01/70 00:00 |