Driving control method and driving system of power device

Abstract

The invention discloses a driving control method and a driving system of a power device. The method comprises the following steps: sampling the voltage of a power tube source, namely a first node, and the grid voltage of the power tube in real time; introducing the input voltage information of the switching power supply into the sampled voltage at the first node to generate a compensation comparison voltage; comparing the compensation comparison voltage with the adjustment voltage, and controlling on and off of a power tube according to a comparison result, so that peak values of output current of the switching power supply are kept consistent, and accurate sampling of source voltage of a power tube is ensured; adjusting the grid voltage of the power tube according to the voltage at the first node and the grid voltage of the power tube, so that the grid voltage of the power tube is increased along with the increase of the voltage at the first node; and stablizing the driving voltage from the grid electrode to the source electrode of the power tube in a range which can start the power tube and does not exceed a drain-source voltage safe working area of the power tube. Thus, the power tube is ensured to be completely conducted without overvoltage damage, and the safety of the switching power supply is improved.

Description

technical field [0001] The invention belongs to the technical field of switching power supplies, and relates to a driving control method of a power device and a driving system thereof, which are used for controlling the driving voltage from the grid to the source of a power tube in a switching power supply to be stable so that the power tube can be turned on and does not exceed the power tube drain. source voltage within the safe operating area. Background technique [0002] The field of switching power supply includes AC-DC, DC-DC and other structures, taking flyback switching power supply as an example, such as figure 1 As shown, it includes a power transistor Q1 and a transformer T1. The drain of the power transistor Q1 is connected to the primary winding of the transformer, and its source is marked as the first node CS. The basic working principle of the flyback switching power supply is as follows: when the primary switching tube, that is, the power tube Q1, is turned ...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problems that the chips in the above-mentioned existing methods require more off-chip devices, which lead to increased system costs, difficulties in PCB layout, and difficulty in realizing on-chip integration, the present invention proposes a drive control method for power devices and a specific implementation circuit Firstly, the internal line voltage compensation method is used to ensure the accurate sampling and monitoring of the source voltage of the power transistor Q1, and then combined with the real-time monitoring of the gate voltage and source voltage of the power transistor Q1, the gate voltage of the power transistor Q1 is accurately controlled, so that the power transistor Q1 The driving voltage VGS from the gate to the source of Q1 is stable within the range that can turn on the power tube and does not exceed the safe working area of ​​the drain-source voltage of the power tube, ensuring that the power tube is completely turned on and at the same time ensuring that the power tube VGS does not overvoltage and damage the power tube

Images