CASCODE DIFFERENTIAL AMPLIFIER WITH CONTROLLED GAIN Russian patent published in 2010 - IPC H03F3/45 H03G3/30 

FIELD: physics, radio.

SUBSTANCE: invention relates to radio engineering and communication and can be used in automatic gain control devices, phase detectors and modulators, in phase-locked loop and frequency multiplication systems or as an amplifier whose voltage transfer ratio depends on the control signal level. The controlled amplifier is the basic block of modern systems for receiving and processing high-frequency and microwave signals, and analogue computer and measurement equipment. The cascode differential amplifier with controlled gain has an input voltage-to-current converter (1), having first (2) and second (3) inputs and first (4) and second (5) current inputs connected to emitters of the first (6) and second (7) output transistors, load elements (8) connected to collectors of the first (6) and second (7) output transistors, a bias voltage source (9) connected to the base of the first (6) and second (7) output transistors through the first (10) and second (9) antiphase sources of the amplified signal. A first additional capacitor (12) is connected between the emitter of the first (6) output transistor and the power supply bus, and collectors of the output transistors (6) and (7) are connected to each other and to the load element (8).

EFFECT: reduced effect of the control signal on the load current.

5 cl, 16 dwg