Circuit for driving gate drive transformer

Abstract

The invention discloses a circuit for driving a gate drive transformer. The circuit comprises a flyback control chip, a diode, a voltage stabilizing diode, a capacitor, and a triode or an MOS tube. The power supply end of the flyback control chip is connected with a power supply; the power supply end of the flyback control chip is respectively connected with one end of the capacitor and the anodeof the voltage stabilizing diode; the cathode of the voltage stabilizing diode is connected with the cathode of the diode; the anode of the diode is connected with the collector of the triode or the drain of the MOS tube; the common connection end of the diode is connected with the synonym end of the primary winding of a gate drive transformer; the base electrode of the triode or the grid electrode of the MOS tube is connected with the driving signal output end of the flyback control chip; the common connecting end of the triode or the grid electrode of the MOS tube is connected with the dotted terminal of the primary winding of the grid driving transformer; and the emitting electrode of the triode or the source electrode of the MOS tube, the grounding end of the flyback control chip and the other end of the capacitor are all grounded. The grid driving transformer has the advantage that the phenomenon of magnetic flux density saturation of the magnetic core of the grid driving transformer in a transient state is avoided.

Description

Technical field [0001] The present invention relates to a gate drive transformer, in particular to a circuit for driving the gate drive transformer. Background technique [0002] In the industrial control industry, switching power supplies are widely used, especially flyback switching power supplies are widely used. Flyback switching power supplies include single-tube flyback switching power supplies and dual-tube flyback switching power supplies. Among them, dual-tube flyback switching power supplies are often used to improve the efficiency of low-power isolated converters. Compared with the single-tube flyback switching power supply, the dual-tube flyback switching power supply requires a floating high-side drive. In the dual-tube flyback switching power supply, the gate of the switching tube is driven by the high level of the gate drive transformer, and the gate drive requires a certain method. If the magnetic core of the gate drive transformer is not in each cycle If it is ...

AI Technical Summary

Problems solved by technology

In order to prevent saturation, a capacitor (DC blocking capacitor) is currently used, and it is one of the most common methods to connect the capacitor in series with the primary winding of the gate drive transformer. This capacitor isolates the DC current, and the magnetic core of the gate drive transformer is in the There will be no magnetic flux density saturation in the steady state, but the magnetic core of the gate drive transformer may be saturated in the transient state. At this time, the DC signal of the drive signal will be lost on the secondary winding of the gate drive transformer. , there is a distortion phenomenon, which causes the level of the gate of the switch tube to drop when the PWM duty cycle increases

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