Tool/software:
Hi. everyone.
I want to input positive power to LDO and output negative power -0.7V.
If I input +5V and GND in reverse like the circuit above,
and output 4.3V compared to +5V,
I expect to output -0.7V compared to GND.
Can I make negative power supply like this?
Is the above circuit correct for -0.7V output?
PMIC_5V5 of GND1, GND2 is a typo.
PMIC_5V is correct.
Thank you for your help.
KYU.
Hello Kang,
You cannot make a negative supply like this. Linear regulators are designed to convert a positive input voltage to a lower positive input voltage, or to convert a negative input voltage to higher (less negative) negative output voltage. With the setup shown in your schematic, you are violating absolute maximum conditions on VIN, VFB and VOUT. So this device will fail if used as illustrated.
You can use LM317 as shown below to generate a negative voltage:
Best regards
Ishaan
