Synchronous rectification control circuit and flyback switching power supply
A control circuit, synchronous rectification technology, applied in control/regulation systems, high-efficiency power electronic conversion, electrical components, etc., can solve problems such as it is difficult to avoid parasitic damping oscillations and malfunctions
Pending Publication Date: 2020-10-30
BCD (SHANGHAI) MICRO ELECTRONICS LTD
View PDF0 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Therefore, controlling the rectifier tube M2 according to the amplitude of the voltage at both ends of the secondary winding is difficult to avoid malfunctions caused by parasitic attenuation oscillations
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0037]The core of the invention is to provide a synchronous rectification control circuit and a flyback switching power supply, which can use the volt-second product of the voltages at both ends of the secondary winding as a judgment standard to distinguish the two secondary windings excited by the normal primary switching action. terminal voltage and parasitic damping oscillation, so as to avoid the phenomenon of mistakenly turning on the secondary side rectifier during parasitic damping oscillation; moreover, the volt-second product threshold of this application can be adaptively set according to the output voltage of the switching power supply, so it is suitable for multiple output voltages switching power supply system.
[0038] In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference ...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses a synchronous rectification control circuit and a flyback switching power supply. The synchronous rectification control circuit comprises a volt-second product comparison circuit and a rectifier tube control circuit. The volt-second product comparison circuit is used for generating an amplitude-second product threshold value positively related to the output voltage of the switching power supply, comparing the volt-second product of the voltage at the two ends of the secondary winding of the switching power supply with the volt-second product threshold value, and generating a turn-on permission signal when the volt-second product is greater than the volt-second product threshold value; and the rectifier tube control circuit is used for controlling the rectifier tubeto be switched on after receiving the switching-on permission signal. Visibly, the volt-second product of the voltages at the two ends of the secondary side winding can be used as a judgment standard,the voltages at the two ends of the secondary side winding excited by normal primary side switch action and parasitic attenuation oscillation are distinguished, and therefore the phenomenon that a secondary side rectifier tube is turned on by mistake during parasitic attenuation oscillation is avoided; and moreover, the volt-second product threshold can be adaptively set according to the output voltage of the switching power supply, thereby being suitable for a switching power supply system with multiple output voltages.
Description
technical field [0001] The invention relates to the field of switching power supply control, in particular to a synchronous rectification control circuit and a flyback switching power supply. Background technique [0002] The flyback switching power supply controlled by the primary side has gradually become an important power supply device for electronic components due to its small size and high efficiency. With the development of electronic technology, the output voltage required by load electronic components is getting lower and higher, and the output power is getting higher and higher. Therefore, the forward voltage drop of the rectifier diode has become the main factor limiting the efficiency improvement of the switching power supply. [0003] At present, the commonly used solution is to use a rectifier tube to simulate a diode for rectification, that is, the so-called synchronous rectification technology. Generally, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transis...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Applications(China)
IPC IPC(8): H02M3/335
CPCH02M3/33592Y02B70/10
Inventor 赵安东彭韶华王峰陈波顾朱泉谢宜忠
Owner BCD (SHANGHAI) MICRO ELECTRONICS LTD