POWER AMPLIFIER

Abstract: The invention relates to devices to amplify electric signals and more particularly, to power amplifiers. The object of the invention is reduction of distortions and the output resistance in power amplifiers in the wide operating frequency. The object is achieved by so in this power amplifier comprising input and output stages, enveloped with the total negative feedback, in addition the local active negative feedback is lead, that lets to stabilize hard the bias voltage of the output stage of a power amplifier, that cases to reduction of distortions and the output resistance in the wide operating frequency.

Description: Power amplifier This invention relates to devices for amplification of electric signals and more particularly, to power amplifiers. It is known a power amplifier described in Copyright of the USSR No.1443128, H03F3/26 comprising the input and output stage enveloped with the total negative feedback. A drawback of this power amplifier is signal lateness of the negative feedback on high frequency that causes to distortion of input signal and increasing of a power amplifier output resistance. The object of this invention is reducing of distortions and output resistance in a power amplifier in the wide operating frequency. The object is achieved by so that in well known power amplifier comprising the input and output stage enveloped with the negative feedback, in addition the local active negative feedback is lead which lets to stabilize the bias voltage of the output stage and thus, lets to reduce distortions and the output voltage in the wide operating frequency of a power amplifier. A presence of a feature in the preferred device, characterised it from the prototype, namely: "... this one is enveloped in addition with the local active negative feedback determines an accordance of the preferred technical embodiment to the criterion "novelty". For checking the preferred technical embodiment to accord to the criterion "essential distinctions" its distinguish features had been compared with features of well known technical embodiments which showed, that in one of them had been used such feature as: "... this one is enveloped in addition with the local active negative feedback that lets to draw a conclusion about an accordance of the preferred technical embodiment to the criterion "essential distinctions". An accordance of the preferred technical embodiment to the criterion "positive effect" is determined by so that well known device-prototype in addition is enveloped with the local active negative feedback, that lets to stabilize the bias voltage of the output stage and thus, to reduce distortions and the output resistance of a power amplifier in the wide operating frequency. Figure is one of variations for embodiment of a preferred power amplifier. It is proposed to provide a power amplifier comprising the positive and negative inputs 1 and 2, the first and second input transistors 3 and 4, the third and fourth output transistors 5 and 6, the first and second resistors 7 and 8 of the negative feedback and the output 9. A power amplifier functions as follows: An input signal comes to the positive or negative inputs 1 and 2 of a power amplifier in which the input is amplified and comes to the output 9. Besides, an amplifying signal comes from the output 9 through the resistors 7 and 8 of the negative feedback to corresponding leads the input transistors 3 and 4, closing thus, a circuit of the local negative feedback with the help of which the bias voltage is stabilized and as a result of that distortions and the output resistance of a power amplifier are reduced. A proposed power amplifier in comparison with well known in addition is enveloped with the local active negative feedback which stabilizes the bias voltage of the output stage of a power amplifier, that lets to reduce distortions of an output signal and output resistance of a power amplifier in the wide operating frequency.

Claims: Claim A power amplifier, comprising input and output stages, enveloped with the total negative feedback, characterised in that in addition this one is enveloped with the local active negative feedback.

Inventors: ALESHIN EUGENE SERGEYEVICH, ALESHIN, EUGENE SERGEYEVICH
Applicants: ALESHIN EUGENE SERGEYEVICH, ALESHIN, EUGENE SERGEYEVICH
Application year: 2001
Main classification: H03F3
IPC codes: H03F1, H03F3