Timeline for MOSFET for 5V high-side switch
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Apr 18, 2018 at 4:28 | comment | added | Spehro Pefhany | Maybe it's oscillating due to the electronic load interacting with the power supply or switch. Bypass caps on the +5? Got an oscilloscope? If not, have you tried a 33 ohm 1W resistor instead of the load? Whatever the root cause is I don't think it is shown on your schematic. | |
| Apr 18, 2018 at 2:03 | comment | added | user31708 | not sure I understand that. The current is being measured by the variable load in both cases. How does it "drop" the voltage, and why does it behave differently connected to the output of the switch than it does when connected directly across the power supply? | |
| Apr 18, 2018 at 0:34 | comment | added | Spehro Pefhany | Your ammeter is dropping the voltage, would be my best guess. | |
| Apr 18, 2018 at 0:07 | comment | added | user31708 | Aha! If I check the supply voltage while I'm testing my switch, the supply voltage is drooping almost as low as the output voltage of the switch. HOWEVER, if I just connect my variable load directly to my power supply, it does not droop. (I can draw up to 600 mA before it even drops below 5.0 volts.) So I am puzzled. Why would the supply droop when using the switch, when it doesn't seem to droop under the same load by itself? | |
| Apr 17, 2018 at 23:58 | history | edited | Spehro Pefhany | CC BY-SA 3.0 |
added 1 character in body
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| Apr 17, 2018 at 23:12 | history | answered | Spehro Pefhany | CC BY-SA 3.0 |