150W inverter schematic ?

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bianchi77

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Everyone,
Does anyone know the schematic for :
**broken link removed**

What transformer does it use ?

Thanks
 

It is almost certainly custom made.

Be aware this unit produces 20KHz square wave output, it can not be used to replace a conventional AC line inverter and will almost certainly damage any equipment that uses a capacitive input dropper, an iron cored transformer or a normal bridge rectifier.

Brian.
 
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    badea

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bianchi77 said:
Everyone,
Does anyone know the schematic for :
**broken link removed**

What transformer does it use ?

Thanks
Click to expand...

What i would do, is to actually purchase a unit and reverse-engineer it.
 

bianchi77 said:
what transformer does it use ?
Click to expand...

At 20 kHz operating frequency, the transformer is a regular ferrite core transformer with multiple taps. There is no regulation (else they will not provide multiple taps) or feedback.

The 20kHz output frequency is most inconvenient for many instruments; perhaps regular lamps will work and perhaps fans will not.

It is a good item to teach students who are beginning to study power supplies.
 

My guess would be that it uses an SG3525 (or similar PWM chip) and drives 2 MOSFETs in push-pull configuration. So the transformer would be center-tapped on the low voltage side. The high voltage side has the voltages marked on the board. Hard to tell if it has feedback or not without seeing if there are components on the under side of the board. But seeing as to how there was no rectification on the high voltage side, my guess would be that there is no feedback/output regulation.
 
A 20 kHz inverter can work with primary switching SMPS, but only if they have fast input rectifiers and no EMI filters effective in the 20 kHz range. Otherwise it can damage the connected device as mentioned by betwixt.

To avoid possible damage, it's safer to rectify the inverter output on board and supply high voltage DC.

Very bad that the Ebay offer doesn't clearly specify the limited application range of the inverter or warns about possible incompatibility and device damage. A DIY shop vendor might be held responsible for giving wrong or incomplete information, at Ebay you can sell all kinds of trash without a risk.
 

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