Abstract: A charge pump for a current switch having at least one current source includes a current summation circuit for generating an output to the current switch. A first current source supplies a first current to the summation circuit. A second current source selectively supplies a second current to the summation circuit. A switch connects the second current source to the summation circuit, such that the current source of the current switch is proportional to the output of the summation circuit.

Abstract: A variable gain amplifier includes a voltage divider input stage for receiving a signal to be amplified. A first voltage amplifier is connected in cascade with the voltage divider for amplifying the signal to be amplified. The voltage divider input stage includes a variable impedance circuit having a second voltage amplifier. The second voltage amplifier includes an input and an output. An impedance element is connected between the voltage amplifier input and output. The voltage divider input stage is connected in series to a second impedance element. Each of the voltage amplifiers has its gain controlled by a bias current source.