abstract the present invention enables a pin on an integrated circuit to provide multiple duties the internal circuit coupled to the selected pin is placed into a high impedance or sampling state based on a recurring signal so that the terminal pin can be sampled the sampled signal is used to control the operation of the circuit such as turning off the internal clock to place the circuit in shutdown mode in that specific example the integrated circuit exits shutdown mode when the sampled signal changes application_number US 24026199 A description fig1 shows a capacitor based quadrupler charge pump circuit 10 having terminal pins 1 8 coupled to input voltage v in output voltage v out external capacitors c 1 c 2 c 3 c in and c out and ground gnd quadrupler charge pump ic 10 comprises first charge pump circuit 20 second charge pump circuit 30 comparator circuit 40 timing circuit 50 sample circuit 70 and bias control circuit 80 one of skill in the art would appreciate that the low voltage start up feature described in u s patent application 09 240 102 entitled u201c ic with enhanced low voltage start up u201d filed concurrently with the present application can be added to this circuit that application is herein incorporated by reference in its entirety voltage v in is input to first charge pump circuit 20 which outputs a voltage approximately two times v in and stores that voltage on capacitor c 2 as voltage v c2 voltage v c2 is then input to second charge pump circuit 30 which outputs a voltage approximately two times voltage v c2 as voltage v out thus output voltage v out is approximately.