| Electronics > Projects, Designs, and Technical Stuff |
| 555 inverter brightness and over current issue |
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| dave_j_fan:
probably smaller core getting saturated , i will adapt to PNP NPN design http://pindiagram.blogspot.com/2012/02/dc-to-ac-inverter.html |
| NiHaoMike:
--- Quote from: dave_j_fan on December 01, 2019, 11:08:13 am ---UC3525A not an option, cost issue --- End quote --- How about TL494? |
| Zero999:
--- Quote from: dave_j_fan on December 01, 2019, 12:27:24 pm ---probably smaller core getting saturated , i will adapt to PNP NPN design http://pindiagram.blogspot.com/2012/02/dc-to-ac-inverter.html --- End quote --- That design is very inefficient due to the huge losses with the 555 driving emitter followers. If you use the original design posted at the start of the thread, with a centre tapped transforer two MOSFETs, the core is less likely to be saturated, since it will be alternately magnetised with opposite polarities, thus be used more efficiently. If you need a smaller solution forget the bulky, inefficient inverter. Use a 12V LED and a small, lightweight, efficient boost converter. |
| dave_j_fan:
--- Quote from: Zero999 on December 01, 2019, 01:54:22 pm --- --- Quote from: dave_j_fan on December 01, 2019, 12:27:24 pm ---probably smaller core getting saturated , i will adapt to PNP NPN design http://pindiagram.blogspot.com/2012/02/dc-to-ac-inverter.html --- End quote --- That design is very inefficient due to the huge losses with the 555 driving emitter followers. If you use the original design posted at the start of the thread, with a centre tapped transforer two MOSFETs, the core is less likely to be saturated, since it will be alternately magnetised with opposite polarities, thus be used more efficiently. If you need a smaller solution forget the bulky, inefficient inverter. Use a 12V LED and a small, lightweight, efficient boost converter. --- End quote --- yes the core saturation was the issue --its resloved! --- 8) 8) 8) -- used Centertapped transformer and dual mosfets -- Achieved good brightness at 230mA so 2200mAH pack will last 8-10hour with 2S4P we can get 20hour backup , which is huge developed an ECO mode , slight less brightness at 155mA on 2200mA ECO mode can pull till 12Long hours All this with palm sized inverter. test shown a 500mA transformer can take two 7Wbulbs ( lower brightness ) but this centertap is very good for one 7W |
| dave_j_fan:
Will the LOGIC mosfets give even better brightness ? AC was approx 185V and the bulbs for 220V do very well now |
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