Test Procedure:
1. Switch the electronic load on and set to 10 mA load; switch all of the digital meters on (assuming they are wired
properly for voltage and current sensing); turn the oscilloscope on with sensing in AC mode and 100 mV per
division vertical and a sweep rate of 5 uS per division. Connect the scope probe to the demo board’s output
terminals.
2. With the AC source OFF, set the current limit on the AC source to 400 mA and the output voltage to 120 Vac.
3. Turn on the AC source and the power supply output voltage should be 12.00 Vdc ± 0.5 V on the DVM.
4. Adjust the electronic load from no load slowly up to 1.75A (full load). The output voltage should remain within 120
mV (1%) of nominal if properly regulating. The output ripple (switching frequency) on the oscilloscope should be
less than 150 mV peak-to-peak at full load. (Note – scope probe tip should be decoupled with a 0.1uF ceramic
capacitor and ground wire should not be used to get best accuracy and max attenuation of switching noise pickup.)
5. Adjust the AC source down to 90 Vac and the power supply output should still be in spec. Return the AC source to
120 Vac.
6. Set the output load to 1.5A, check the efficiency. Effic = (Vout x Iout)/Pin. It should be greater than 79%.
7. Continue to increase the load slowly and the over-current protection should kick in between 2~3A. This should
result in a “hick-up” start-stop type of operation.
8. Set the load back to 1.5A and the power supply should recover with proper output voltage.
9. Adjust the electronic load to back to zero, switch the load off, and check the input power (standby power). It should
be below 100mW.
10. Adjust the AC input to 230 Vac and repeat tests (3) through (8) with the exception of (5).
11. Switch the AC source off and disconnect the demo board.
End of Test.
Parts Change for 12Vout Version (See BOM) from 5V Board:
Vout set: R14 to 1K ohms; R1 to 39K
Output Capacitors: C9A/B to 1000 uF, 16V
Transformer: T1 to ICE Components # TO12157
Test Parameter Limits for 12Vout demo board:
Vout nominal = 12.0V +/- 0.5V
Full load = 1.75 amps
Efficiency = > 79% (at full load)
Overcurrent = 2.0 to 3.0 amps @ 120 Vac input
Standby power = < 100 mW