A charge pump circuit

A charge pump circuit (1) comprises a load capacitor (math) across which an output voltage of approximately twice the supply voltage (math) is provided. A pump capacitor (math) is charged from the supply voltage (math) through first and second charge switches (SC1,SC2), and a first pump switch (SP1) raises the voltage on the pump capacitor (math) to twice the supply voltage (math), which is then in turn applied to the load capacitor (math) through a second pump switch (SP2). The switches (SC1, Sc2, SP1, SP2) are each provided with a high resistance switch (SR1) and a low resistance switch (SR2) parallel to each other. A select pin (math) of the switches (SC1,SC2,SP1, SP2) alternatively selects the high resistance (SR1) and the low resistance switch (SR2). On initial charging of the capacitors (math) the high resistance switches (SR1) are selected for minimising the initial current drawn from the supply voltage (math) and after the capacitors (math) have been initially charged, the high resistance switches (SR1) are deselected and the low resistance switches (SR2) are selected for steady state operation of the charge pump circuit (1).