Digital controlled amplifier

A digital controlled amplifier, comprising:

• an input terminal for receiving an analog signal to be amplified,
• an output terminal for receiving an amplified analog signal,
• a current transfer circuit adapted to receive an input current signal and to produce an output current signal in response thereto, said current transfer circuit including control terminal means to receive a control signal, said control signal governing the magnitude of the output current signal relative to the input current signal,
• input circuit means connected between the input terminal and the current transfer circuit for presenting an analog signal at the input terminal as an input current signal for the current transfer circuit,
• output circuit means connected between the current transfer circuit and the output terminal for presenting an output current signal from the current transfer circuit as an output analog signal at the output terminal,
• means for producing a reference current,
• a plurality of bit circuits adapted to produce a corresponding plurality of bit currents, said bit currents being progressively decremented with respect to the reference current and to each other,
• a plurality of digital input circuits, corresponding in number to the number of bit circuits, for receiving a multi-bit digital control signal, and
• a plurality of bit switches, each switch connected to interface between a respective digital input circuit, a respective bit circuit and the control terminal means for the current transfer circuit, each bit switch completing or interrupting a circuit connection between its respective bit circuit and the control terminal means in response to the digital signal at its respective digital input circuit, whereby as a collective result of the operation of each of the bit switches a control signal is applied to the current transfer circuit to control the magnitude of the output analog signal at the output terminal.