MEMORY EXPANDING DEVICE AND PORTABLE MOBILE DEVICE USING THE SAME

摘要

PURPOSE: A memory expanding device and a portable mobile device using the same are provided to expand a memory in a high speed by connecting the memory expanding device and an external device through an optical interface only when an additional memory is required. CONSTITUTION: An interface unit (1010) exchanges information with a portable mobile device using an optical signal, and a volatile memory unit (1030) stores the information. A control unit (1020) controls the volatile memory unit in response to the optical signal transmitted through the interface unit. The interface unit includes an optical transmitter (1010a) that converts an output electrical signal transferred from the control unit into an output optical signal and an optical receiver (1010b) that converts an input optical signal received from the portable mobile device into an input electrical signal. The optical transmitter includes a direction control circuit, a level shifter, and an optical module.