Flyback type power supply control system

Abstract

The invention discloses a flyback type power supply control system. The flyback type power supply control system comprises a transformer, a power tube, a diode, a first resistor, a second resistor, a third resistor and a power supply controller, wherein one end of a primary winding of the transformer is connected with an input system voltage, the other end of the primary winding is connected with a drain end of the power tube, a source end of the power tube is connected with the ground through the first resistor, one end of an auxiliary winding of the transformer is connected with the ground, the other end of the auxiliary winding sequentially passes through the diode, the third resistor and the second resistor and is connected with the source end of the power tube, the power supply controller is provided with a sampling end and a control end, the sampling end is connected between the third resistor and the second resistor, the control end is connected with a gate end of the power tube, and the power supply controller is used for driving the power tube to be periodically switched on, acquiring a detection voltage during switch-on and switch-off periods of the power tube, judging whether the working condition is an abnormal sate or not according to the detection voltage and driving the power tube to be switched off when the working condition is judged to be an abnormal state. By the mode, more safety protection can be achieved by using a few pins.

Description

technical field [0001] The invention relates to the technical field of basic electronic circuits, in particular to a flyback power supply control system. Background technique [0002] The flyback power supply system is more and more widely used in the existing power supply system, so its safety and reliability are also paid more attention by users. The safety standards of various countries also require the safety and security of power supply products and household appliances. Various tests and specifications are performed for reliability. [0003] In the application of the current flyback power supply system, the small size has become an important factor to attract more manufacturers to use. In the existing flyback topology applications, especially in secondary side flyback applications, output overvoltage protection, external overtemperature protection, etc. are required, and in some power systems, the leading edge of the peak current of the primary winding of the transfor...

AI Technical Summary

Problems solved by technology

In applications that require higher reliability, the power supply system is required to provide the above-mentioned safety protection. However, due to the limitation of the pin number of the control chip, more safety protection cannot be provided, so in order to realize these safety protections, the control chip needs more pins for sampling and detection, and this will inevitably lead to problems such as large package volume of the control chip and many peripheral circuits, which will cause defects such as high system application cost and large power supply

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