We have tested the two different boost modules from TI and have run into a few discrepancies with the specifications listed in the datasheet.
For all tests, we are using the following test conditions:
Vin: 5VDC
Ta: 25°C
Vout: 12VDC
Iout: 1A
PTN04050C
We found that, at 25°C this device will only deliver 1A for 1:30 before it goes into protection mode. We have no fan and based on the datasheet, we should see no de-rating at 1A until ambient reaches 55°C. Once the device cools [and comes out of protection], it will only run for an additional 20 seconds and then turn off for 8 seconds. This cycle will repeat indefinitely.
We were able to identify the stable point as ~750mA which would allow the device to run indefinitely at 25°C. It appears as though the system shuts down when it’s components reach 113°C. The other issue we have is the efficiency rating. This part is rated around 85% efficiency with 12VDC output @ 1A but our measurements on two different units show only 67%. I understand that the specs may be slightly off and some is probably lost in the test leads but a 22% delta is a bit large. PT5040 The plot above also shows the efficiency for the ‘5040 and it is clear that the part is a horrible performer above 500mA and is ~33% under spec at 1A out! Again, the de-rating curve for this part shouldn’t affect performance until 55C. The data also shows that the device was only able to deliver ~350mA before reducing the output voltage. In fact, 1A @12V was never even possible. Are these devices performing unexpectedly or are they missing something?
