Semiconductor device voltage supply for a system with at least two, especially stacked, semiconductor devices

A system comprising:

• a first semiconductor device, and
• a second semiconductor device,
• wherein the first semiconductor device and the second semiconductor device each comprise a voltage supply device,
• wherein said voltage supply device of said first semiconductor device is connected to said second semiconductor device, so that said voltage supply device of said first semiconductor device can provide a supply voltage for operation of said second semiconductor device, and
• wherein the system is adapted such that, in an external access operating mode of the second semiconductor device, the voltage supply device of said second semiconductor device provides the supply voltage for operation of the second semiconductor device, and, in a standby or refresh operating mode of the second semiconductor device, the voltage supply device of said first semiconductor device provides the supply voltage for operation of the second semiconductor device.