| ??? 03/15/12 22:30 Read: times |
#186711 - maybe a couple of mosfets ... Responding to: ???'s previous message |
and a couple of resistors ...
If you have a couple of resistors configured as a divider between Vcc and Gnd, and you then use a mosfet pair, usually an N-channel and a P-channel in an soT of some sort, often costing MUCH less than $1.00US, you can pull to GND with the N-channel, and to Vcc with the P-channel, using each of two I/O pins. When the P-channel is "ON", you conduct from Vcc to the mid-voltage of the divider, and when the N-channel is "ON", you conduct from the mid-voltage to GND, and when neither is "ON", you have the mid-voltage node of the divider. Buffering the mid-voltage to the output through an NPN voltage follower would not be a bad idea, depending, of course, on the required output impedance. Those MOSFET's, BTW, are inverters, so pay attention so you don't turn both of them "ON" at the same time. RE |
| Topic | Author | Date |
| Making a pulse with 3 different voltage level! | 01/01/70 00:00 | |
| No best but consider a voltage divider | 01/01/70 00:00 | |
| derivative with a DAC? | 01/01/70 00:00 | |
| derivative with configurable ports | 01/01/70 00:00 | |
| Thanks Per And Erik | 01/01/70 00:00 | |
| which derivative | 01/01/70 00:00 | |
| with an OPamp | 01/01/70 00:00 | |
| Thanks Erik | 01/01/70 00:00 | |
| So, you need to make -15V, 0V and +15V? | 01/01/70 00:00 | |
| Hi Dear Kai | 01/01/70 00:00 | |
| 74hc series | 01/01/70 00:00 | |
FPGA | 01/01/70 00:00 | |
| I think you can do it wih one resistor. | 01/01/70 00:00 | |
| Most 8051 Systems????? | 01/01/70 00:00 | |
| Well add a pull-up resistor then | 01/01/70 00:00 | |
| Would prefer to not have to match internal resistors | 01/01/70 00:00 | |
| You cannot match the weak internal active pull-up! | 01/01/70 00:00 | |
| Being pedantic. | 01/01/70 00:00 | |
| Hi David | 01/01/70 00:00 | |
| maybe a couple of mosfets ... | 01/01/70 00:00 | |
| Thanks Richard | 01/01/70 00:00 |