Products > Test Equipment
Inside the Owon P4603/P4305 linear PSU
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Pnoxi:
Today I bought a new power supply Owon P4603 60V/3A, 180W, resolution 1mV/1mA, 3.7 inch TFT LCD display, RS232 - 137.55€ (My version does not have USB and Voltage/Current Curve)



Some components:
4xNPN - NJW0281G
CPU - GD32F103 + C8051F350 (ADC,DAC?)
Op-amp - SGMOP17C ?
Toroid 250VA ?

Pros:
60V/3A (P4603), 30V/5A (P4305)
Linear PSU
Nice, clear display shows all the necessary information
Simple, intuitive control
Response time <100uS (I can't verify it!)
Adjustment accuracy 1mV/1mA
Power measurement
Backlit button (Output On/Off)

Cons:
The Keylock button must be held for at least 10 seconds
Unable to switch off OVP, OCP (maximum set value 3.1A / 61V)
The changed settings are not saved immediately (system settings, stored values), the PSU must be left on for some time
It is noisy at maximum load
It does not have a USB only RS232


Manual:
http://files.owon.com.cn/probook/Single_Output_Power_Supply_USER_MANUAL.pdf

Site:
https://www.owon.com.hk/products_owon_1ch_liner_dc_power_supply

Few photos:















Kleinstein:
The shunt and the power transistors look good. However the current rating on the transformer is somewhat suspicious, as I don't see a switched mode part. Normally a 3 A transformer is good for some 1.8-2 A of DC current (if the filter cap is no too large). So I would be a little careful using the full 3 A current for an extended time, especially at higher voltage.

The ratings on the transformer could be about 220-250 VA: 3 A at some 65 V + some smaller windings.
The 65 V value is rather high - lots of spare voltage for ripple.

THE C8051F350 sound like a µC with integrated high resolution ADC.
Pnoxi:
A weak transformer is a problem for most cheap power supplies. :-[
Behind the cooler are two relays for connecting the transformer winding.

I made a video review, you can find it in the first post. (I don't have an oscilloscope for a more accurate review...)
Pnoxi:
Here are some images from oscilloscope. I'll do a more thorough test later.

Set voltage is 3.3V.

Power On (Main Power 230V)


Short (CV -> CC):

Cliff Matthews:
Good review. If Owon could drop the price another $50, these would fly off the shelves! I like the vertical layout and deeper cabinet, it makes for more bench room (perhaps they could have tilted the display up 10-15 degrees). One thing about your changes not being saved (eg: at 3:52 you were supposed to hit OK to confirm changes).
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