Negative to Positive DC/DC

Hi Matthew

maybe you could use a boost converter as following. could you just share the input voltage range, output voltage and output current? other engineers may have better suggestion.

Jasper,

Thank you for your response. The input voltage range will be between -30V and -20V, with a -24V nom. Output would be +5V @500mA max.

I found a Tina file slvm755.tsc, is there a way I can modify it to show the system? Also, What would the level shifter look like?

Lastly, I would consider other topologies like a flyback if you think it could be a better option.

Regards,
Matthew

Hi Matthew
Please refer this application note i just found "Negative Input to Positive Output made SIMPLE"
www.ti.com/.../snva740.pdf

as i know, the circuit can's simulate in TINA, because the internal circuit of the model is connected to zero volt. but we need to connect the GND pin of the IC to -24V in this circuit. i would suggest you post a new question in the forum about the simulation tool. maybe engineer there have a solution. should be this link "e2e.ti.com/.../"

flyback is also a solution, efficiency should be higher. but you need a transformer and the output voltage feedback is still a challenge.

Jasper,

Reviewing the datasheet I discovered a few discrepancies between the schematic (figure 2) on P.2 and the BOM (table 1) on P.8. Can you please advise which are correct?


Item DESIGNATOR Schematic Value BOM Value
---- ---------- --------------- ----------
1 Cc 0.22uF 0.1uF
2 Cin1 56uF 10uF
3 Cin2 10uF 1uF
5 Cout3 10uF 1uF
12 Rfbt 4.07k Not standard Value
13 Cc2 1nf Not in BOM

Hi Matthew
i had replied you through email