Timeline for Discrete N-channel-MOSFET driver switching circuit with NPN and PNP transistor
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Feb 26, 2023 at 18:36 | comment | added | Tim Williams | @Dakalaom CC has no voltage gain, so you'd have a hard time getting a 12V swing out of a 3 or 5V logic signal with it :) | |
| Feb 26, 2023 at 17:26 | comment | added | Dakalaom | What would be the difference to a common collector; thus PNP on high-side and NPN on low-side, besides changing the logic (on/off). Would there be any other benefits/disadvantages? Because you say, that the circuit above is especially great for pulsed current. | |
| Feb 26, 2023 at 16:04 | comment | added | Tim Williams | @Dakalaom Not quite: the configuration matters as well as the lower resistance. The emitter follower arrangement is good for pulsed current like this. These also don't show a dedicated gate resistor, which is usually preferred for several reasons (but can be quite small, ~ohms, giving fast results still). And an NPN (common emitter) would have a pull-up resistor for collector load. | |
| Feb 26, 2023 at 15:57 | history | edited | Tim Williams | CC BY-SA 4.0 |
Added details
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| Feb 26, 2023 at 15:42 | vote | accept | Dakalaom | ||
| Feb 26, 2023 at 15:41 | comment | added | Dakalaom | Simply speaking: Charge and Discharge speed during high frequency switching of the MOSFET gate pin via separate NPN and PNP transistors without resistors in the collector/emitter path is preferred instead of diodes or just pulldown-resistor in combination with only 1 NPN transistor. Is this an accurate summery for the overall problematic in the circuit mentioned in my question | |
| Feb 26, 2023 at 15:18 | comment | added | Tim Williams | @sai Or during initialization (typically tristate on reset), good point. | |
| Feb 26, 2023 at 15:09 | comment | added | sai | in case there is a possibility of MCU being OFF when +12V is present, Q1 B-E resistor will help define the B-E voltage. | |
| Feb 26, 2023 at 14:28 | vote | accept | Dakalaom | ||
| Feb 26, 2023 at 14:28 | |||||
| Feb 26, 2023 at 14:26 | history | answered | Tim Williams | CC BY-SA 4.0 |