Patent ID: 8683414

Claim:
A semiconductor integrated circuit device formed on one chip comprising: a first functional block connected to a first power supply and a second power supply; a second functional block connected to the first power supply and a third power supply and communicating with the first functional block; a third functional block connected to the first power supply and a fourth power supply and communicating with the first functional block; a fourth functional block connected to the first power supply and a fifth power supply and communicating with the second functional block; a fifth functional block connected to the first power supply and a sixth power supply and communicating with the second functional block; a first power switch shutting down the first functional block; a second power switch shutting down the second functional block; a third power switch shutting down the third functional block; a fourth power switch shutting down the fourth functional block; and a fifth power switch shutting down the fifth functional block, wherein the second to sixth power supplies are independently supplied from each other, wherein the first functional block is shut down by the first switch only when the second to fifth functional blocks are shut down, wherein the second functional block is shut down by the second switch only when the fourth and fifth functional blocks are shut down, and wherein the signal transmission paths from the first functional block to each of the second to fifth functional blocks, and from the second functional block to each of the fourth and fifth functional blocks have no indefinite signal propagation circuits, and wherein the first functional block comprises a retaining latch circuit that saves a data stored in a latch circuit provided in one of the second to the fifth functional blocks.