Patent ID: 8654059

Claim:
A portable apparatus having a battery as a power supply voltage source, comprising: a plurality of light emitting elements of different drive voltages required for the light emission; a plurality of display devices illuminated by said light emitting element; and a light emitting element drive apparatus to which said plurality of light emitting elements are connected in parallel and driving one or more light emitting elements among the plurality of light emitting elements, and a control device to control a displaying function of said plurality of display devices and to control said light emitting element drive apparatus in response to mode of said light emitting element drive apparatus; and a synchronous signal supply circuit which is controlled by said control device supplies a synchronous signal to said light emitting element drive apparatus wherein said light emitting element drive apparatus includes: a plurality of drive circuits connected to corresponding light emitting elements of said plurality of light emitting elements and driving the corresponding light emitting elements with luminances based on set values; a decision circuit for deciding a drive voltage value required for the highest light emission among one or more light emitting elements driven to emit light based on drive states of said plurality of light emitting elements in response to the decision result of said decision circuit, wherein said light emitting element drive apparatus drives a plurality of light emitting elements illuminating a plurality of display devices by a least one of light emitting element drive apparatus.