Step Up/Down Inverting Switching Regulator

DC to DC converter/regulator MC34063A.  Has an input range of 3V to 40V, output switch
current of up to 1.5 amp.  Step up, step down and invert capability. 
This is the unit we used in the high voltage ringer circuit for the port-o-rotary phone!
 

תיעוד:
MC34063 Datasheet