| 摘要 |
<p>A power supply unit for supplying electric current of a supply voltage to a control unit in an electronic control system has switching regulator dropping an input voltage to an intermediate voltage, a first series regulator producing electric current of the supply voltage from the intermediate voltage, and a second series regulator producing electric current of the supply voltage lower than electric current produced in the first series regulator. During the standby mode of the control unit, an FET of the switching regulator is locked to the on state to accumulate electric charge in a capacitor of a smoothing circuit, while an output transistor of the first series regulator is locked to the off state. When a wake-up condition is satisfied in the control unit, the FET starts the switching operation, and the output transistor immediately starts the driving operation while using the charge supplied from the capacitor.</p> |
