AUDIO-FREQUENCY POWER AMPLIFIER Russian patent published in 1998 - IPC

FIELD: electronic engineering. SUBSTANCE: amplifier has input stage 1 built around operational amplifier 2 with negative feedback circuit common for ac and DC currents in the form of voltage divider. Operational amplifier 2 is supplied with power through parametric regulators built around transistors 3 and 4. Voltage amplifying stage 22 uses balanced circuit arrangement with two transistors 23 and 24 connected into common-base circuit and is provided with circuit setting potential across these transistors which has two groups of parallel-connected diodes 26,27 and 28,29 integrated by resistor 30. Current amplifying unit 31 uses balanced circuit arrangement and has stages built around transistors 32-37 connected into common- collector circuit. Output stage of unit 31 has two series- connected resistors 38 and 39 connected to respective transistors 36 and 37. Unit 31 is also provided with temperature controller 43 using transistors 44 and 45 of different structure; power amplifier has negative feedback circuit common for DC and ac currents. EFFECT: reduced nonlinear distortions and improved reliability. 1 dwg