Patent ID: 8183900

Claim:
A charge pump circuit for connection to another circuit via an output node of the charge pump and for causing a current to flow either into or out of the other circuit via the output node in dependence on a current output by first and second current paths in the charge pump, each current path comprising: a current source; and a current control device having two switched nodes, one of which is arranged to receive a current from the current source, and a control node arranged to control a current flow between the two switched nodes in dependence on a voltage at the control node, the current control devices of the first and second paths being of the same type such that they are responsive to the same polarity of voltage at their control node to be conducting between their switched nodes; the charge pump further comprising: a capacitive element having first and second capacitive plates; and a switching arrangement arranged such that, during a first time period, the first and second capacitive plates are each in communication with a respective one of the current paths, whereby a current output by the first current path causes an electrical charge to be formed on the first capacitive plate and a current output by the second current path causes an electrical charge to be formed on the second capacitive plate, and during a second time period, the first and second capacitive plates are connected to a reference voltage and the output node respectively, the electrical charge formed on the first and second capacitive plates during the first time period thereby being discharged to form a current at the output node.