Simplified power system with a single power converter providing low power consumption and a soft on/off feature

摘要

A computer power system with a keyboard, a computer housing, and a single AC to DC power converter that generates a DC power signal as long as it is energized by an AC power source. The power system is digitally controllable by the central processing unit (CPU) or from soft on/off switches on the keyboard and computer housing. This is made possible by a soft on/off controller that receives soft on/off control signals from the CPU and the soft on/off switches and in response generates a power transition signal that triggers shaping circuits to connect (soft on) or disconnect (soft off) power system output lines and power lines from the converter. The shaping circuits also ensure that the rising edge of a digitally switched power system output signal resembles the rising edge of the converter's cold-start power signal. Following a soft off event,, the power system is in a low power standby state as power is not being supplied to the computer's power hungry components even though the converter is still generating a power signal.