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General Tests:

•  Program microcontroller
•  Verify the TVS diode function protects against overvoltage on analog lines
•  Do a full system test with all of the rails powered and make sure nothing explodes

48V Power

•  Power onboard + touch test, verify components and the board itself does not get too hot
•  Verify all ICs, details, LEDs, etc. are powered on successfully. Communicate with all peripherals

STM:

•  Verify the enable pins (N-CH MOSFET gate) can be driven high and low (PC1, PC3, PC5, PA6)
•  Gate and source pins are reversed in the footprint
•  Verify the analog read of the current sense amplifier outputs (PC0, PC2, PA5, PA7)
•  Verify the analog read of the VBAT rail (PC4)

Electrical:

•  Verify the 48V outputs can be enabled and disabled via N-CH FET (can draw load from the output when enabled, can’t otherwise)
•  Verify the analog output of the amplifier matches expectations

5V Power:

•  Power onboard + touch test, verify components and the board itself does not get too hot
•  5V_1
•  5V_2
•  Verify all ICs, details, LEDs, etc. are powered on successfully. Communicate with all peripherals
•  5V_1
•  5V_2

STM:

•  Verify the enable pins can be driven high and low (PC14, PC11, PB9, PD2)
•  Verify the STM can read the state of the OC pins accurately (PC13, PC12, PC10, PB8)
•  Verify the analog reads of both of the 5V rails (PB7, PC15)
•  Both of the pins for this are not analog capable, but was able to read from a peripheral

Electrical

•  Verify enable condition on all 4 switches (can draw load from the output when enabled, can’t otherwise)
•  Verify output current limit (2.4A)
•  The current limit is actually 2A not 2.4A
•  Verify the OC pin goes low in this condition

Problems:

• at 1A load, the 5V output is dropping to 4.3V

  • Actually even at the power supply input it is 4.3V, so maybe it’s the power supply

  • Does it even when connecting power supply directly to the reload, maybe power drop through wires

    • Ya it is, its 5v right at the power supply terminal but

• Highside switched shut down the output at 2A not 2.3 or whatever

17V Power

•  Power onboard + touch test, verify components and the board itself does not get too hot
•  Current sense amplifier blew up when powerd
•  Verify all ICs, details, LEDs, etc. are powered on successfully. Communicate with all peripherals

STM:

•  Verify the enable pin (N-CH MOSFET gate) can be driven high and low (PB2)
•  Verify the analog read of the current sense amplifier output (PB1)
•  Verify the analog read of the 17V rail (PB0)

Electrical:

•  Verify the 17V output can be enabled and disabled vis N-CH FET (can draw load from the output when enabled, can’t otherwise)
•  N-CH footprint has source and drain pins reversed
•  Verify the analog output of the amplifier matches expectations
•  Verify the TVS diode function protects against an oversimplification of signal

Problem:

• When 17V was powered without 48V, there was a leakage to 48V, only 100 ohms between the rails

  • IC VCC is 48, though it is measuring at 17

• When 48V was supplied without 17V, nothing

• When both 17V and 48V were connected, IC blew up, shorted 48V though the IC,

• I think pull resistors on N-CH/P-CH load switch has the output enabled by default

  • No, they are off by default

Changes for Next Rev

• R44 and R45 are 0603 and should be 0805

• Change 0.1uF 10V to 50V for consistency (5V high side switched)

• 3.3k (r2) 0603 part number

• There are 16V, 50V and 100V 1uF caps on the board

• It should probably double the power rating on the current sense resistors for the 24V buck

• Add label to 3v3 led

• N-Ch fet description says 340mS instead of 340 mA

• Add polarity indicators to terminals

• STM reset button footprint is wrong, shorts itself out

• Add testpoint labels where convenient

• SHDN on CAN should have a test point

• RST pin on microcontroller should have testpoint w label

• Add clippy testpoints to all of the voltage rails

• reduce the small terminal through hole size for better alignment

• Both 5V rail ADC pins do not go to ADC capable pins

• Current sens +/- pin name wrong

• N-CH footprint is wrong

• LED doens’t work

• 17V current sense should be supplier by 17V so it doesn’t blow up

• Either combine the 5V rails or make sure all of the start up conditions are on the same 5V rail

• Make the current gain max out at 1.8V, change out the TVs diode for one that hopefully works,

  • In the firmware, the STM should shutdown the output when the voltage reaches 1.8V so it has a margin of error to shut down the output before it becomes dangerous to the stm