Mobile telephone power management circuit includes fast and slow clock circuits, enabling reduction of power consumption in standby mode

摘要

The circuit offers a standby mode, in which the telephone still maintains synchronization with the mobile network. The mobile telephone (1) has an aerial (2) communicating with the network (3). In order to reduce the consumption of current by the mobile telephone circuit in its standby mode, first (11) and second (12) circuits are used providing rapid and slow clock pulses respectively. The slow clock signal is regularly sampled by the rapid clock signal before cutting the supply of the first circuit (11) when the telephone is to be changed into its standby mode. The telephone receives information from the network indicating a difference between a known date and a previous date. Processing with the slow and rapid clock signals, and this date information, enables the telephone to remain in synchronism with the network.