JPS5875905A - Amplifier - Google Patents

Abstract

PURPOSE:To obtain a wide-band high-voltage amplifier by bringing a control circuit connected between a power source and an output transistor (TR) under the control of an output signal, and using a low dielectric strength TR as the output TR. CONSTITUTION:An output part 2 consists of the complementary circuit of output TRs 7 and 8, which are applied with plus and minus potentials +B and -B through TRs 12 and 11. The TRs 12 and 11 are applied with proper biases through resistances 16 and 15 and Zener diodes 14 and 13. As an output voltage rises, the emitter potential of the TR12, i.e. the collector potential of the output TR7 also rises following up the output voltage, but the voltage between the collector and an output terminal is held constant and the voltage between the collector of the output TR8 and the output terminal is constant.

Description

[Detailed description of the invention] The present invention relates to a broadband high voltage output amplifier.

Conventionally, it has been easy to obtain transistors with a wide band and a low withstand voltage, but it has been difficult to obtain a transistor with a wide band and a high withstand voltage. For this reason, high voltage amplifiers are limited by the band of the transistors used, making it difficult to widen the band.

The present invention has been made to eliminate the above-mentioned drawbacks, and an object of the present invention is to feed back the output voltage, thereby making it possible to use a low-voltage transistor in the output section, and providing a wide-band high-voltage amplifier.

FIG. 1 shows a conventional signal amplifier. 1 is the front stage section of the amplifier. The output section 2 is composed of a complementary circuit of output transistors 7.8, each of which has a complementary circuit.
8 is supplied with a stable bias by a constant current source 3, a diode 4, and a bias stabilizing resistor 5.6.

Further, the potential element B of iE and the negative potential -B are applied to the collector of the output transistor 7.8. Input terminal 9
After the signal applied to is amplified in the front stage section 1, the output (2) is supplied to the output section 2 and output to the output terminal 10. In order to output high voltage, the output transistors 7.8 are high voltage transistors, but with current technology it is not possible to create high voltage and wide band transistors. This narrows the bandwidth of the amplifier.

The present invention has been made to eliminate the above-mentioned drawbacks, and embodiments will also be described below.

In FIG. 2, transistors 7.8 &! Positive and negative potentials 10 B are applied through transistors 12 and 11, respectively.

-B is applied. The pace of transistor 12 is resistor 16. The base of the transistor 11 is connected to the Zener diode 14, and the base of the transistor 11 is connected to the resistor 15. Zener diode 13
, and both transistors are supplied with an appropriate bias. Now, when the output voltage increases, the emitter potential of the transistor 12, that is, the collector potential of the output transistor 7 increases following the output voltage, but the voltage between the collector of the output transistor 7 and the output terminal does not change and remains constant. Further, the voltage between the collector of the output transistor 8 and the output terminal is also constant. Output transistor at design 7.8
If the voltage applied to the output transistor is kept low, a low voltage transistor can be used as the output transistor.

As described above, according to the present invention, a low withstand voltage transistor can be used as an output transistor, so a wideband high voltage amplifier can be constructed.

[Brief explanation of the drawing] FIG. 1 shows a conventional amplifier 1, FIG. 2 shows the amplifier of the present invention. l: front stage section, 2: output section, 3: constant current source.

Claims (1)

[Claims] In an amplifier that outputs a signal through two complementary connected transistors, the amplifier has a control circuit connected between a power supply and the transistor, and controls the control circuit with the signal to apply the signal to the transistor. The amplifier is characterized in that it controls a power supply voltage.