SU1238198A1 - Class d amplifier - Google Patents

Abstract

FIELD: electrical engineering; used in drive control systems. The performance is developed. The amplifier contains a pulse-width modulation unit 1, each amplifier arm is executed on a power transistor (T) 2 of the same structure, switching T 3 of the same structure, controlling T 4 other structure, diode 5, bias resistor 6, T of feedback 7 other, a structure limiting resistor 8, an optocoupler photodiode 9, five resistors 10-14. The transition from closed state to open state is an avalanche-like regenerative character due to a strong positive feedback. The process of locking is also an avalanche. The switching processes are characterized by processes with a negative dynamic resistance. The goal is achieved by the introduction of a photodiode 9, a resistor. 8, T 7, five resistors 10-14,, 1 Il. (L

Description

The invention relates to electrical engineering and can be used in electric drive control systems.

The purpose of the invention is to improve speed.

The drawing shows the electrical circuit of the class D amplifier.

Class D amplifier contains block

Moreover, at the time of opening the transistors of the diagonal shoulders between the shoulders, a positive connection also arises through the photodiode 9 and the limiting resistor 8, an increase through the diode 5 of one arm causes an even greater opening of the similar commutator and power transistors of the diagonal shoulder. In the moment

1 pulse width modulation (PWM), 10 photodiode effect terminations

9 begins the reverse process of recording. In this case, the control transistor 4 is locked, which leads to the locking of the switching 3 and power 2 transistors. The locking of the commutation transistor 3 leads to the locking of the transistor 7 feedback. The process of locking also occurs as an avalanche. In essence, the switching process is characterized by a process with a negative dynamic resistance.

Each arm of a class D amplifier is made on a power transistor 2 of one structure, a switching transistor 3 of the same structure, a control terminal of a transistor 4 of a different structure, a diode 5, a bias resistor 6, a transistor 7 feedback of another structure limiting the resistor; 8, the photodiode 9 of the optocoupler, the first, second, third, fourth, and fifth resistors 10, AND, 12, 13, and 14, respectively. .

Class D amplifier works as follows.

In the initial state, all the transistors are locked and current does not flow through the load. When exposed from the output of the 1 PWM block to the photodird 9 of the light pulse optocoupler, the latter goes into the conducting state. In this case, to the base of the ynpaa-jo structure, the control transistor

Opening potential is applied to the base transistor 4 and the base of the similar control transistor of the diagonal arm. The control transistor 4 begins to open, and the current ({through the bias resistor 6 and the control transistor 4 opens the switching 3 and the power 2 transistors. As the switching transistor 3 opens, the voltage on the resistor 14 decreases to the base of the transistor 7 feedback through the third resistor 12 is applied opening its potential. As the feedback transistor 7 opens, the current through the diode 5 and the control transistor 4 increases, due to which the switching transistor 3 enters the saturation even more, saturation and feedback transistor 7, the current of which through the fourth resistor 13 is added to the current of the switching transistor 3. This total current introduces the power transistor 2. to saturation.Thus, the transition of the transistors from the closed to the open state has an avalanche-like generative character due to the strong positive feedback besides.

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Moreover, at the time of opening the transistors of the diagonal shoulders between the shoulders, a positive feedback through the photodiode 9 and the limiting resistor 8 also occurs, an increase in the current through the diode 5 of one arm causes an even greater opening of the similar switching and power transistors of the diagonal shoulder. In the moment

9, the reverse process of locking begins. In this case, the control transistor 4 is locked, which leads to the locking of the switching 3 and power 2 transistors. The locking of the switching transistor 3 causes the locking of the transistor 7 feedback. The process of locking is also an avalanche. In essence, the switching processes are of the nature of a process with a negative dynamic resistance.

Claims (1)

Invention Formula A class D amplifier with control from a pulse-width modulation unit, made according to a bridge circuit, containing in each arm of power and commutation transistors one five 0 another structure, a series-connected diode and a bias resistor, collectors of power transistors connected to the respective power supply sources, and bases - to the emitters of the corresponding switching transistor, characterized in that, in order to improve speed, between the bases of the control diagonal transistors are included, sequentially the connected photodiode of the optocoupler and the limitation of vacancies; a resistor; a feedback transistor of a different structure is inserted into each arm, first, second, third, fourth, and fifth The resistors, the base of the switching transistor through the first resistor is connected to the collector of the control of the transistor, the base of which is connected to the base of the transistor through the fourth resistor through the fourth resistor connected to the base of the power transistor, the connection point of the cathode diode and one of the terminals of the bias resistor is connected to the emitter of the control transistor, and the emitter of the reverse transistor 5 five 3 12381984 connection, another pin of the resistor and to the commutator displacement and one of the transistor transistors, the diode anode is connected to the resistor is connected and connected to the feedback collector of the transistor, the other power supply bus wiring, and the photodiode input of the optocoupler connected to that resistor is connected to the point j to the output of the second-to-third c-modulation pulse-to-mass junction unit.