SU1363439A1 - Cascode amplifier - Google Patents

Abstract

This invention relates to radio engineering and provides increased efficiency. The cascode amplifier contains a high-voltage power supply 1, transistors (T) 2 and 3, a load 4, a resistive voltage divider 5, and a low-voltage power supply 6. direct displaced diode (PSD) 7, reverse-biased diode 8, voltage divider 9 and filter capacitor 13. When the opening signal arrives at base T 2 through PDM 7 and the base-emitter transition T 3, an unlocking current flows. At the same time T 3 is open. . A reverse diode 8 prevents T 3 from entering saturation mode. When the PSD 7 locks the signal to the base T 2, it closes and the voltage on T 2 and 3 is distributed equally. When switching T 2 and 3, the T 2 lock delay does not affect the uniform distribution of the voltage across T 2 and 3. The voltage divider 9 formed by chains of resistor 10, PSD 11, and capacitor 12 reduces the resistance of the excitation circuit T 3 AC, which also reduces the uneven distribution of voltages on T 2 and 3. DED 7, Backward Diode 8 and Divider 9 are introduced. 1 Il. with (L with SG5 with 4 WITH with

Description

This invention relates to radio engineering and can be used in output stages operating in class D mode.

The purpose of the invention is to increase the efficiency of the amplifier.

The drawing shows a circuit diagram of a cascade amplifier.

The cascode amplifier contains high-voltage power supply 1, first 2 and second 3 transistors, load 4, first resistive voltage divider 5, low-voltage power supply 6, first 7 and second 8 reverse biased diodes, second voltage divider 9, resistor 10, additional direct offset diode 11, capacitor 12 and filter capacitor 13.

Kyskodny amplifier works as follows.

If the opening signal arrives at the base of the first transistor 2, then the voltage drop across its collector-emitter junction is minimal, therefore, the unlocking current flows from the low-voltage power supply 6 through the first displaced diode 7 and the base-emitter junction of the second transistor 3 what the second transistor 3 is also open. The second reverse-biased diode 8 prevents the second transistor 3 from entering the saturation mode. When the first transistor 2 receives a blocking signal at the base, it is locked. The tapping potential of the first resistive divider 5 is equal to half the voltage applied to the series-connected first 2 and second 3 transistors, so that the first direct diode 7 is closed. The base current of the second transistor 3 is small, since the closed first transistor 2 is connected to its emitter circuit. The voltage on the emitter of the second transistor 3 is close to the voltage at its base, and since the base of the second transistor 3 has a voltage equal to half applied to a series-connected first 2 and second 3 transistors, the voltage on the transistors is distributed equally

When switching the first 2 and second 3 transistors, the delay of locking the first transistor 2 does not affect

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It does not uniformly distribute the voltages on the first 2 and second 3 transistors, since the second transistor 3 does not enter saturation mode, but is controlled by the collector current of the first transistor 2 and the voltage at the tap of the first resistive divider 5. The use of the second voltage divider 9, formed by two chains of resistor 10, a direct-moving diode 11 and a capacitor 12, allows reducing the excitation circuit of the second transistor 3 in alternating current, which also reduces the uneven distribution of voltages Consequently, the first 2 and second 3 transistors are connected, and ensures the formation of a safe path for switching off the first 2 and second 3 transistors, which leads to an increase in the efficiency of the amplifier in the mode of class D.

Claims (1)

Invention Formula A cascode amplifier containing first and second transistors connected in series with respect to a high-voltage power supply, connected by common emitter circuits — a common base, the base of the first transistor being the input of the cascade amplifier, and the base of the second transistor being connected as well as a low-voltage power source and a filter capacitor, one output of which is connected to a common bus, characterized in that, in order to increase the efficiency, the emitter of the first transistor is connected With the first pins of the first resistive voltage divider, low-voltage and high-voltage power supplies, and between the second low-voltage power supply and the base of the second transistor, the first direct diode is inserted, the collector of the second transistor is connected to the second terminals of the first resistive voltage divider and high-voltage source, and through the inserted second reverse-biased diode, with the second output of the low-voltage power supply, while between the first and the second outputs of the first resistive voltage divider introduced the second voltage divider, the tap of which is connected to the tap of the first re31363439 a diode and a capacitor, while the other arm of the second divider is connected to the connection point of the first connected resistor, connected by a resistor, and biased by a second recirculated offset diodes.