Patent ID: 8255730
Filing Date: 2012-08-28
Classification: G06F,Y02D

Abstract:
1. A power management unit for controlling power supply voltages of first and second power domains to which first and second CPUs belong respectively, the power management unit comprising: a power IC which supplies first and second power supply voltages to the first and second power domains respectively; a clock generating portion which generates first and second clocks and supplies the first and second clocks to the first and second CPUs respectively; and a power and clock control portion which is connected both to the power IC and to the clock generating portion, wherein: the power and clock control portion controls the power IC to change the second power supply voltage in response to a power supply voltage change request for the second power domain from the first CPU and controls the clock generating portion to change the frequency of the second clock in response to a frequency change request for the second clock from the second CPU; and the power and clock control portion prohibits acceptance of the second clock frequency change request in response to the second power domain power supply voltage change request unless the second power supply voltage reaches a voltage level in accordance with the power supply voltage change request.