Semiconductor device, radio communication terminal using same, and clock frequency control method
View Patent ↗A semiconductor device 1 includes a clock generation circuit 15 that changes a frequency of an output clock signal according to a control signal div, an arithmetic circuit (e.g., CPU 0 ) that operates according to the clock signal, a storage circuit (e.g., IC 0 ) that is activated according to access from the arithmetic circuit CPU 0 , a memory access detection unit 12 that detects a number of accesses from the arithmetic circuit CPU 0 to the storage circuit IC 0 , and when the number of accesses increases, outputs a request signal (e.g., psreq 1 ), and a clock control circuit 14 that generates the control signal div for lowering the frequency of the clock signal according to the request signal psreq 1.
1. A semiconductor device comprising:
a clock generation circuit that generates a clock signal;
an arithmetic circuit that operates according to the clock signal;
a storage circuit that is activated according to access from the arithmetic circuit;
a memory access detection unit that detects a number of accesses from the arithmetic circuit to the storage circuit and applies a weight to the number of accesses; and
a clock control circuit that lowers the frequency of the clock signal when a variation of the weighted number of accesses exceeds a variation threshold.
2. The semiconductor device according to claim 1 , wherein the weight is a value for one access.
3. A clock frequency control method for a clock signal supplied to a semiconductor device with an arithmetic circuit that operates according to the clock signal and a storage circuit that is activated according to access from the arithmetic circuit, the clock frequency control method comprising:
detecting a number of accesses from the arithmetic circuit to the storage circuit;
applying a weight to the number of accesses; and
lowering a frequency of the clock signal when a variation of the weighted number of accesses exceeds a variation threshold.
4. The method according to claim 3 , wherein the weight is a value for one access.