An adjustment circuit for controlling conduction time

Abstract

An adjustment circuit for controlling conduction time belongs to the technical field of electronic circuits. The reference voltage generation circuit is used to generate the required reference voltage. In the voltage sampling circuit, by controlling the minimum on-time control terminal to be suspended or connected to the ground level or an off-chip resistor, different signals are generated and connected to the on-time control circuit to make the on-time The transmission gate in the control circuit outputs different voltage values, and then generates the output signal of the conduction control circuit after passing through the filter composed of the first capacitor and the first resistor; the minimum conduction time output circuit is based on the output signal of the conduction control circuit, the external Feedback of the enable signal and the output signal of the minimum on-time output circuit generates voltage control signals with different on-times. The invention can accurately control the turn-on and turn-off of the switch tube in the switching power supply, and solves the influence of the process deviation of the resistance on the turn-on time.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, in particular to an adjustment circuit for controlling conduction time. Background technique [0002] In the power switch control circuit, due to the influence of technology and external factors, the power switch tube source-drain voltage or current often has glitches or oscillations, which will cause the power switch tube to be turned on or off by mistake, resulting in the failure of the designed system. Unstable and poor reliability. In order to solve this problem, an on-time adjustment circuit is usually added to the driver IC to reduce burrs and oscillations. The traditional method is to use a fixed time in the circuit to turn on or adjust the gate resistance of the drive output terminal, but because different drive ICs have different device processes and models, the required time is also different, which makes the use of fixed time The method has great limitations; secondly, be...

AI Technical Summary

Problems solved by technology

The traditional method is to use a fixed time in the circuit to turn on or adjust the gate resistance of the drive output terminal, but because different drive ICs have different device processes and models, the required time is also different, which makes the use of fixed time The method has great limitations; secondly, because the external resistance changes greatly with temperature and is easily affected by the process, the method of adjusting the gate resistance will cause a large deviation between the obtained result and the ideal value

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