switch 70 a transmits a first input control signal 58 a which in one embodiment is either a first control signal 62 e g clock signal or a second control signal 67 e g complementary clock signal to a control terminal 63 a of the first switch 15 a optionally the clock signals 62 67 can be replaced by other forms of switching signals the first input to control signal 58 a causes the voltage provided at the output terminal 46 a of the first switch 15 a to alternate between the first voltage and the second voltage the clock signal 62 is applied as a second input control signal 58 b to a control terminal 63 b of the second switch 15 b a second control switch 70 b transmits a third input control signal 58 c which is either the first control signal 62 or the second control signal 67 to a control terminal 63 c of the third switch 15 c the third input control signal 58 c causes the voltage provided at the output terminal 46 c of the third switch 15 c to alternate between the first voltage and the second voltage a first selection signal 105 a is applied to a selection terminal 68 a of the first control switch 70 a and controls the operation of the first control switch 70 a a second selection signal 105 b is applied to.