In a circuit, there is somewhat of a symmetry of power sources being connected together. If they are of equal voltage they would be connected in parallel increasing current at the same voltage. Or if they are of different voltages yet have the same current they are connected in series to output higher voltage at the same current.
Is it possible to have a circuit where there is a power source that would output high current at low voltage, while the other power source would output lower current at high voltage?
Having separate power source for each Voltage and Current?
Answer
Yes, it's common to have different power supplies with different voltages and current capabilities in a system. For example, consider a typical mid-range desktop PC power supply (Corsair HX750):
+3.3V@25A, +5V@25A, +12V@62A, -12V@0.8A, +5VSB@3A
The motherboard and other boards will make additional voltage rails from those provided by the power supply, generally using switching regulators (sometimes inside the IC package). For example, the CPU itself might require around a volt at rather high current (perhaps 50A), and that would be expensive to distribute at that voltage- so the 12V rail is stepped down very close to the die itself.
Embedded systems similarly typically have a plethora of supply voltages- 1.8V, 3.3V, 5V, -5V, maybe +12 or +/-15V.
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