Timeline for Use MOSFET as low frequency PWM variable resistor for step down regulator
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Jan 19 at 18:21 | comment | added | Sim Son | Note that I mean to add the pot to the feedback resistors, not to replace the resistors with a pot. Btw, 10 Ohm for R1 is faaar too low, the datasheet recommends values between 240 Ohm and 1.5 kOhm. You're probably also fine with 10 kOhm if it's just to drive a fan, but you shouldn't go lower due to unneccessary power dissipation. In case you didn't know: the outputcurrent does not flow through the resistors. | |
| Jan 19 at 18:16 | comment | added | Sim Son | That depends on the voltage range you want. There are also different options how it can be connected to the feedback network, each having a different transfer functions (voltage will not be linear). If it's for a 12V fan you probably don't actually need voltages below 5V(?). | |
| Jan 18 at 23:42 | comment | added | arielnmz | Couldn't edit my prev comment: what would be a good digipot for this application? | |
| Jan 18 at 23:35 | comment | added | arielnmz | Unfortunately, I haven't been able to source them locally in my country. Global marketplaces will take about a month and given how cheap they are I don't really want to spend 30x the cost for a couple in shipping fees nor order 100 of them... | |
| Jan 18 at 20:27 | history | answered | Sim Son | CC BY-SA 4.0 |