JPH02186705A - Push-pull amplifier bias circuit - Google Patents

Abstract

PURPOSE:To reduce a bias current by permitting an input current to flow from a collector to an emitter in a transistor(Tr) and permitting it to flow from a collector to an emitter in other Tr through a resistor, a coil, and an output transistor so as to attain grounding through resistor. CONSTITUTION:The collector of Tr 3 is connected to the first terminal of a first winding in a transformer 2, and the emitter is connected to the first terminal of a second winding in the transformer through the resistor 11 and the coil 13. On the other hand, the collector of Tr 4 is connected to the second terminal of the second winding in the transformer 2, and the emitter is grounded through a resistor 12. The second terminal of the first winding in the transformer 2 and the first terminal of the second winding in the transformer 2 are grounded through respective capacitors 14 and 15, and the second terminal of the first winding is set to be the power terminal of feeding. Since the DC bias current flows in two Tr in serial in such constitution, the current can be reduced to half.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a Bushdel amplifier bias circuit.

[Conventional technology]

The collectors of transistors 3 and 4 are connected to both terminals of the winding 20, and power is supplied from the center tap of the winding of the transformer 2, and the emitter of each transistor 3 and 4 is grounded through a resistor 11 and 12'i, respectively. are doing. 1 in internal causes
is the input transformer, 2 is the output transformer, 5.6.15.1
9.20 is a capacitor.

? , 8.9, 10.11.12 are resistors, and 16 is an input terminal.

17 is an output terminal, and 18 is a power supply terminal.

[Problem to be solved by the invention]

The above-mentioned conventional Bushzol amplifier has the drawback that it consumes a large amount of current because sufficient collector currents are passed through both transistors in order to maintain good distortion characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bushing amplifier bias circuit which eliminates the above-mentioned drawbacks and reduces the collector current of the transistor.

[Failure to solve the problem]

According to the present invention, in a Bushgur amplifier using an output transformer having 3 turns and 1 tJt, the collector of the first transistor is connected to the first terminal of the first winding of the transformer, and the emitter of the first transistor is connected to the first terminal of the first winding of the transformer. 1 resistor and a coil to a first terminal of a second winding of the transformer, and a collector of a second transistor is connected to a second terminal of a second winding of the transformer; The emitter of the second transistor is grounded via a second resistor, and the second terminal of the first winding and the first terminal of the second winding of the transformer are each grounded via a capacitor. The first winding or the second winding or the first and 20th windings are grounded through a capacitor, and the first winding of the transformer is grounded through a capacitor. A push-pull amplifier bias circuit characterized in that terminal No. 2 is used as a power supply terminal is obtained.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention.

In FIG. 1, the collector of the first transistor 3 is connected to the first terminal of the first winding of the transformer 2, and the emitter of the first transistor 3 is connected through the first resistor 11 and the coil 13i. the collector of the second transistor 4 is connected to the second terminal of the second winding of the transformer 2; The emitter is grounded via a second resistor 12, and the second terminal of the first winding and the first terminal of the second winding of the transformer 2 are respectively grounded via a capacitor or a capacitor. Connect via.

Furthermore, the first winding, the second winding, or the first and second windings are grounded via a capacitor, and the second terminal of the first winding of the transformer is used as a power supply terminal.

In such a configuration, the current supplied from the power supply terminal 18 flows through the output transformer 2 from the collector to the emitter of the transistor 3, passes through the resistor 11 and the coil 13, and passes through the output transformer 2.

Flows from the collector of transistor 4 to the emitter.

From the resistor 12 to the ground point.

As a result, the DC bias current flows through the two transistors in series, so the current can be halved compared to the conventional one. Also, at this time, by selecting the beginning of the winding of the output transformer as shown in Figure 1, the magnetic fluxes caused by the direct current generated in the two windings cancel each other out, thereby preventing magnetic envelopment caused by the direct current. This point is the same as the prior art.

〔Effect of the invention〕

As explained above, in the present invention, the bias current is set to about 172, which results in the effect of saving power consumption.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a Bushnor amplifier employing the present invention, and FIG. 2 is a block diagram of an example of a conventional push-pull amplifier. 1...Input transformer, 2...Output transformer, 3.4
...Transistor, 5, 6, 14.15j19.20
...Capacitor, 7-12...Resistor, 13...
Coil, 16...Input terminal, 17...Output terminal, 1
8...Power supply terminal.

Claims (1)

[Claims] In a push-pull amplifier using an output transformer with one or three windings, the collector of the first transistor is connected to the first terminal of the first winding of the transformer;
connecting an emitter of a transistor to a first terminal of a second winding of the transformer through a first resistor and a coil;
A collector of a second transistor is connected to a second terminal of a second winding of the transformer, an emitter of the second transistor is grounded via a second resistor, and a collector of the second transistor is connected to a second terminal of a second winding of the transformer. The second terminal of the wire and the first terminal of the second winding are each grounded or connected through a capacitor, and A push-pull amplifier bias circuit characterized in that the second winding is grounded via a capacitor, and the second terminal of the first winding of the transformer is used as a power supply terminal.