Switchable voltage follower and bridge-type driving circuit using switchable voltage follower

The present invention relates to a switchable voltage follower and bridge-type driving circuit apparatus using switchable voltage follower. The switchable voltage follower is composed of an output transistor pair, three switches and one operation amplifier. By using a polarity terminal to control each switch, a circuit is switched to a pull-up voltage follower or a pull-down voltage follower. The bridge type circuit apparatus is composed of two sets of switchable voltage followers such that a driving function of bridge-type push-pull is obtained by alternately driving these two sets of switchable voltage followers.