Patent ID: 8823209

Claim:
A semiconductor device comprising: a plurality of power domains, power of which is allowed to be on/off-controlled, including a first and a second power domains, the second power domain being not supplied with power during a time when the first power domain is not supplied with power, the second power domain being enabled to be supplied with power during a time when the first power domain is supplied with power, the first power domain being supplied with power before supplying power to the second power domain; and a power management unit configured to control power supply to the plurality of power domains, wherein the power management unit includes: a plurality of power controlling circuits assigned to the power domains, respectively, the plurality of power controlling circuits having a same circuit configuration as each other, each of the plurality of power controlling circuits configured to output a valid signal indicating that power is supplied to the assigned power domain, a first power controlling circuit of the plurality of power controlling circuits assigned to the first power domain, a second power controlling circuit of the plurality of power controlling circuits assigned to the second power domain, and wherein: the valid signal output from the first power controlling circuit is input to the second power controlling circuit as an enable signal allowing the second power controlling circuit to control power supply to the second power domain and to output the valid signal corresponding to the second power domain, and the valid signal output from the second power controlling circuit is input to the first power controlling circuit as a disable signal prohibiting a power cut-off of the first power domain.