Half-bridge circuit

Abstract

The invention discloses a half-bridge circuit being capable of suppressing direction connection of a power tube. The half-bridge circuit has two power tubes with alternate conduction. High-frequency isolating conversion is carried out on a direct-current voltage of an external DC source by a voltage transformer under alternate conduction of the two power tubes and outputting is carried out. The transformer contains two primary-side windings that have identical numbers of turns, opposite dotted terminals, and different inductance values and are used for transmitting voltages to secondary sides alternately to realize input-output conversion. Simultaneous conduction detection of the two power tubes is realized by obtaining the change of voltage signal difference values of the dotted terminals of the two primary-side windings; and thus corresponding control signals can be generated to turn off drive signals of the corresponding power tubes, thereby realizing short-circuit prevention and stable outputting. According to the half-bridge circuit, a phenomenon that two power tubes Q1 and Q2 are burned due to heavy short-circuit currents generated by simultaneous conduction of the two power tubes Q1 and Q2 can be avoided; and thus the circuit reliability is substantially improved.

Description

technical field [0001] The invention belongs to the field of conversion circuits, and more specifically relates to a half-bridge circuit. Background technique [0002] Half-bridge circuits (also known as half-bridge converters) are widely used in PWM motor control, DC-AC inverter, electronic ballast and other occasions. Among them, it includes two power switch tubes connected in series to form a bridge arm. The two power switch tubes are controlled by an antiphase signal. When one power tube is turned on, the other is turned off, so that a pulse voltage signal is obtained at the output point. [0003] like figure 1 As shown, a traditional half-bridge converter generally includes a power switch tube Q1, a power switch tube Q2, a voltage divider capacitor C1, a voltage divider capacitor C2, and a DC blocking capacitor C3, wherein the power switch tube Q1 and the power switch tube Q2 form a bridge of the half bridge arm; the capacitor voltage division branch formed by connect...

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned technical means may have complex topology, cumbersome control methods, complicated overall structure of the circuit, or poor control effect, and the problem of simultaneous conduction cannot be avoided.

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