A lot depends on what "gave 5v power supply to raspberry pi from the pc" means in practice (via a USB2 port, USB3 port, via molex/SATA connector, ...) and, if using a USB port, whether or not the PC does per port current limiting, and how it handles current supply to devices that are not enumerated.
Typical bare board consumption of a 4B is stated as 600mA. USB 2 devices are not supposed to draw more than 500mA and that's after enumeration (so the host knows and agrees how much to supply/allow). Before that, 100mA maximum. If the PC enforces those limits all bets are off.
If the PC port is USB C and you have an early production 4B it may have the resistor problem that makes the PC think it's a pair of headphones and doesn't need any power supply.
Typical bare board consumption of a 4B is stated as 600mA. USB 2 devices are not supposed to draw more than 500mA and that's after enumeration (so the host knows and agrees how much to supply/allow). Before that, 100mA maximum. If the PC enforces those limits all bets are off.
If the PC port is USB C and you have an early production 4B it may have the resistor problem that makes the PC think it's a pair of headphones and doesn't need any power supply.
Statistics: Posted by thagrol — Mon Jan 06, 2025 3:32 pm