SU1341712A1 - Bridge power amplifier - Google Patents

Description

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The invention relates to radio engineering and can be used in the output stages of key audio frequency amplifiers.

The purpose of the invention is to increase the efficiency.

Figure 1 shows the structural diagram of the bridge power amplifier; Fig. 2 shows an embodiment of a controlled current source.

The bridge power amplifier contains linear cascades 1 and 2, key cascades 3 and 4, input transformer

5 and a controlled current source 6.

Bridge power amplifier works as follows.

In the absence of an input signal due to the small initial current of the bridge power amplifier, the voltage drop across the controlled source

6 current is small. In this case, the supply voltage of the linear cascades I and 2 is significantly lower than that of the key cascades 4 and 3, i.e. DC potential of the bridge diagonal is close

to the potential of the common bus line stages 1 and 2. This mode of the bridge power amplifier provides the maximum efficiency.

With an increase in the input signal and in the presence of a load current given

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controlled current source 6 increases. At the same time, the negative voltage from the output of the bridge power amplifier, acting on one or another, depending on the polarity of the output voltage, controls the input source 6 of the current, changes its conductivity so that the voltage drop across it remains almost unchanged any amplitude of the input signal. There is no common-mode change in the potentials of the output terminals (diagonal) of the bridge power amplifier with respect to the common bus, i.e. no - undesired increase in the voltage of the power supply of the linear cascades 1 and 2 and the associated deterioration in the efficiency of the bridge power amplifier with increasing input signal. Another positive effect of the proposed bridge power amplifier is the reduction in output distortion associated with a stable DC potential across the common bus.

The controlled current source 6 can be made, for example, according to the scheme depicted in FIG. It is a conductivity controlled by a negative voltage across the load of a bridge power amplifier.

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Editor T. Parfenova

Tehred M. Khodanych

Order 4444/56

Circulation 901 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, st {-35, Raushsk nab. 4/5

Production and printing company, Uzhgorod, st. Project, 4

Proofreader S. Shekmar

Claims (1)

BRIDGE POWER AMPLIFIER, each arm of which is made on a linear and key stages, the combined outputs of which are the corresponding output of the bridge power amplifier, and the combined inputs are connected to the corresponding output of the secondary winding of the input transformer, the midpoint of which is connected through a current source to the common line cascade bus bridge power amplifier, characterized in that, in order to increase efficiency, the current source is made controllable, while its control inputs are connected to the corresponding bridging outputs of a bridge power amplifier. Figure 1 "SU„ „1341712 ¹ 1341