A linear system and an EER system are used in combination such that the EER system can also be used in a cellular phone with a wide output dynamic range. In the EER system, linear control of an amplifier becomes difficult in a low output range. Thus, use of the EER system is limited to a high output range, and the linear system is used in the low output range as in the past. A power efficiency is improved while requirements of linearity are satisfied by this structure. An effective circuit structure is proposed for a switching control system for two systems. In addition, an up-converter is constituted in combination with a step-down element with high responsiveness, whereby a power supply voltage control circuit for the EER system with a wide control range and high responsiveness is provided.