disclosed is a variable drive current driver circuit , comprising : a pair of push - pull circuits for driving a load circuit complementarily ; a first current source circuit for having a bias current flow into the pair of push - pull circuits ; a second current source circuit for having the bias current flow out of the pair of push - pull circuits ; and a control circuit for varying both the bias current flowed by the first current source circuit and the bias current flowed by the second current source circuit according to a control signal .