The sodium/potassium pump uses energy (ATP) because it has to pump sodium ions out of the cell and potassium ions into the cell. This is against the concentration gradient. The difference between the sodium outside and the potassium inside produces an electrical gradient. The outside of the cell is more positive than the inside. This allows a signal or "current" to be transmitted.
Proteins that carry out passive transport include channel proteins and carrier proteins. Passive transport is "passive" because it does not use energy. The use of passive transport is also called "facilitated diffusion." Proteins that carry out passive transport includes the proton pump and the sodium-potassium pump; these require energy to function.