PCS - Bring Up & Test Plan (WIP)

Post-Assembly Design Test:

Before we start testing the PCB under high voltage conditions, it is important to first check the board over while it is disconnected from power or any load. To do so, check all connections for proper solder joints, make sure diodes are oriented correctly, and nothing is shorting. Resistance, diode and continuity checks with a multimeter will be useful for this. Additionally, the boards will be inspected against the 3D viewer on Altium to catch any immediate issues.

Please note before we get into HV testing, that proper safety precautions must be taken to minimize the risk associated with high voltages. This includes protecting from dangers like exploding capacitors and careful use of equipment such as the HV supply and oscilloscope.

Quick Design Test:

As a minimum, the following tests are strongly recommended once the PCB is assembled:

1. Maximum Drain Voltage – Verify that VDS of InnoSwitch4-CZ does not exceed the maximum continuous drain voltage and SR FET do not exceed 90% of breakdown voltages at the highest input voltage and peak (overload) output power in normal operation and during start-up.

2. Maximum Drain Current – At maximum ambient temperature, maximum input voltage and peak output (overload) power. Review drain current waveforms for any signs of transformer saturation or excessive leading-edge current spikes at start-up. Repeat tests under steady-state conditions and verify that the leading edge current spike is below ILIMIT(MIN) at the end of tLEB(MIN). Under all conditions, the maximum drain current for the primary switch should be below the specified absolute maximum ratings.

3. Thermal Check – At specified maximum output power, minimum input voltage and maximum ambient temperature, verify that temperature specification limits for InnoSwitch4-CZ IC, transformer, output SR FET, and output capacitors are not exceeded. Enough thermal margin should be allowed for part-to-part variation of the RDS(ON) of the InnoSwitch4-CZ IC. Under low-line, maximum power, a maximum InnoSwitch4-CZ SOURCE pin temperature of 110 °C is recommended to allow for these variations.

(Source : Innoswitch4-CZ Datasheet)

Voltage Test at Test Points

Efficiency: 

Tools:

• HV supply

• DMM

Procedure:

1. Open https://docs.google.com/spreadsheets/d/1j4ExuqtmNUZ8RIEcoD0iXZhGC9C0vgVWgL9Wz4GZ-gI/edit?usp=sharing

2. Set HV supply to specified test voltage (90V-150V)

3. Log current output value from HV supply in https://docs.google.com/spreadsheets/d/1j4ExuqtmNUZ8RIEcoD0iXZhGC9C0vgVWgL9Wz4GZ-gI/edit?usp=sharing

4. Measure with DMM Vout (output voltage), put value in https://docs.google.com/spreadsheets/d/1j4ExuqtmNUZ8RIEcoD0iXZhGC9C0vgVWgL9Wz4GZ-gI/edit?usp=sharing

5. Measure with DMM Iout (output current), put value in https://docs.google.com/spreadsheets/d/1j4ExuqtmNUZ8RIEcoD0iXZhGC9C0vgVWgL9Wz4GZ-gI/edit?usp=sharing

6. The spreadsheet will tell efficiency (in %)

7. Repeat 2 - 6 for each row of https://docs.google.com/spreadsheets/d/1j4ExuqtmNUZ8RIEcoD0iXZhGC9C0vgVWgL9Wz4GZ-gI/edit?usp=sharing

(Also use R10 current shunt for current sensing if necessary to validate)

This includes measuring the voltage drop over the shunt with DMM and using Ohm’s Law. The purpose if verify the accuracy of our readings. Could add a column in PCS Test Table to show percent deviation?

Voltage Regulation:

Procedure

1. Check that output is 12V under different inputs 90V - 150V while testing Efficiency

2. Comment out any outputs that are outliers

Load Stability:

Test at different current loads and modulate to see if there's any issues

Tools:

• Load Tester

• Oscilloscope

Procedure

• Set Load Tester to CC mode, and set to 1-5A to test

• Use oscilloscope at output

• See and note voltage regulation (+/- 10%)

• Comment any discrepancies

Results:

Efficiency: 

(show average efficiency of PCS board)

Voltage Regulation:

(note any issues and discrepancies with output voltages)

Load Stability: