| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a larger power saving effect by deciding and supplying the combination of an operation frequency and a drive current capable of operating system logic. SOLUTION: A frequency control circuit 1 decides a frequency to be supplied to the system logic and reports it to a frequency variable oscillation circuit 2 by using control signals (a). For the decision method of the frequency, an operation is performed by a maximum frequency capable of operating the system logic at the time of a normal operation, and at the time of wanting to reduce power consumption, at the time of using a battery for instance, the system logic is operated at a low frequency. Simultaneously, a drive current decision circuit 3 decides a minimum drive current capable of operating the system logic at the frequency decided in the frequency control circuit 1 based on the control signals (a). The drive current decided by the drive current decision circuit 3 is reported to a drive circuit 4 by the control signals (c), and by turning parallelly connected transistors on and off, only a required current is driven.</p> |
