Timeline for Op-amp circuit voltages after power off
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 4, 2018 at 0:35 | vote | accept | Anonymous | ||
| Jun 15, 2017 at 15:16 | comment | added | Spehro 'speff' Pefhany | Yes, you are correct. The 220K/47uF controls how fast the op-amp input approaches 0V when powered up- the average DAC output is Vdda/2. It is a high-pass filter with a sub-1Hz rolloff. If your entire amplifier was DC coupled and had no power-up mute the speaker cones would slam over to one side and then slowly return. You don't need to change them as a result of changing the other parts. Diodes failing in the field should not be a big worry- they can handle 600mA surge 200mA continuous and 30V, none of which should exist in your circuit. | |
| Jun 15, 2017 at 15:07 | history | edited | Spehro 'speff' Pefhany | CC BY-SA 3.0 |
deleted 3 characters in body
|
| Jun 15, 2017 at 15:04 | comment | added | Anonymous | I am slightly hesitant adding diodes this way, if one of them fail in the field I may get into big trouble. DAC outputs voltage of 0-3.3 V (always positive), thus 1k must be enough to keep 3.3 mA internal clamping current. Would you agree? Should I also change 220k resistor value (and by the way, why it is there, and why 220k?) | |
| Jun 15, 2017 at 14:59 | history | answered | Spehro 'speff' Pefhany | CC BY-SA 3.0 |