A charge pump circuit comprising: an input terminal for connection to an input voltage; a common terminal; first and second output terminals, said first and second output terminals being coupled, in use, to said common terminal via respective first and second reservoir capacitors (CR1, CR2); at least one pair of first and second flying capacitor terminals for connection, in use, to a flying capacitor (Cf); a switch network for interconnecting said input terminal, said flying capacitor terminals, said common terminal and said first and second output terminals; and a controller for operating said switch network; characterised in that said controller is operable in first and second modes to generate output voltages at said output terminals wherein the output voltages are different in the different modes, and where, in the first of said modes the controller is configured to operate said switch network in a sequence of states having at least first and second states to generate at said output terminals a first positive output voltage (Vout+) and a first negative output voltage (Vout-) that are each equal in magnitude to a fraction of the magnitude of said input voltage, wherein the switch network is operable in the first state to divide the input voltage between the at least one flying capacitor and the first reservoir capacitor in series and operable in the second state to apply at least one flying capacitor's portion of said divided voltage across the second reservoir capacitor; and wherein the circuit further comprises an input selector for receiving, in use, a plurality of different voltage inputs and operable to select one of said plurality of different voltage inputs (+Vin1,..., +VinN) as said input voltage to be connected to the input terminal. an input terminal for connection to an input voltage; a common terminal; first and second output terminals, said first and second output terminals being coupled, in use, to said common terminal via respective first and second reservoir capacitors (CR1, CR2); at least one pair of first and second flying capacitor terminals for connection, in use, to a flying capacitor (Cf); a switch network for interconnecting said input terminal, said flying capacitor terminals, said common terminal and said first and second output terminals; and a controller for operating said switch network; characterised in that said controller is operable in first and second modes to generate output voltages at said output terminals wherein the output voltages are different in the different modes, and where, in the first of said modes the controller is configured to operate said switch network in a sequence of states having at least first and second states to generate at said output terminals a first positive output voltage (Vout+) and a first negative output voltage (Vout-) that are each equal in magnitude to a fraction of the magnitude of said input voltage, wherein the switch network is operable in the first state to divide the input voltage between the at least one flying capacitor and the first reservoir capacitor in series and operable in the second state to apply at least one flying capacitor's portion of said divided voltage across the second reservoir capacitor; and wherein the circuit further comprises an input selector for receiving, in use, a plurality of different voltage inputs and operable to select one of said plurality of different voltage inputs (+Vin1,..., +VinN) as said input voltage to be connected to the input terminal.