One-time side control switching power regulator

Abstract

The invention relates to a power supply regulator of switching over type controlled by primary side, which consists of a transformer with primary side winding and an auxiliary winding being separately coupled to positive and negative electric rails, a switch being series-connected to two said windings, a control circuit coupled to switch and auxiliary winding, a supply capacity for providing power to control circuit, a dipolar body coupled to negative rail and supply capacity. The auxiliary winding comprises a leakage inductance for releasing stored energy to supply capacity through diode when switch is off and for storing energy when switch is on. The setting method between the transformer and the switch in the invention can improve the efficiency of the switching over type power supply regulator and reduce the electromagnetic interference.

Description

Technical field: [0001] The invention relates to a power regulator, in particular to a switching power regulator controlled by the primary side. Background technique: [0002] By the way, switching power regulators have been widely used to provide adjustable voltage and current. At present, the focus of research on power regulators is how to make power regulators more efficient to save power. A switch mode power regulator usually includes a control circuit, a switch and a transformer. The control circuit is used to sense the output voltage and / or output current of the switch mode power regulator, and generate a control signal to control the switching and adjustment switching of the switch The output voltage and / or output current of the type power regulator. [0003] see figure 1 , is a circuit diagram of a conventional switching power regulator. As shown in the figure, a conventional switching power supply regulator includes a transformer 10, which includes a primary side...

AI Technical Summary

Problems solved by technology

The first disadvantage is that the leakage inductance of the transformer 10 leads to high power consumption. In addition, because the leakage inductance will store energy, it is easy to form a high voltage surge, which is easy to damage the switch 11. Therefore, the conventional switching power regulator is designed to protect the switch 11. There is a snubber circuit, which includes a snubber diode 19, a snubber capacitor 20 and a snubber resistor 21, used to consume the energy stored in the leakage inductance of the transformer 10, avoiding the formation of high voltage surges to protect the switch 11

[0013] The second disadvantage is the lack of regulation of switching power supply regulators under light load and no load conditions

If the output load of the switching mode power regulator is lower than the auxiliary winding N A When the load is high, the energy stored in the transformer 10 can only pass through the diode 18 and the auxiliary winding N A Released to the supply capacitor 17, so that when the switch 11 is turned off, the rectifier 13 will remain in the off state, so the output voltage V of the switch mode power regulator O not available from the auxiliary winding N A Feedback to the control circuit 25, so in the light load and no load state, the detection voltage V generated by the voltage detection terminal VS DET1 It is only related to the voltage of the supply terminal VDD, so the conventional switching power supply regulator lacks adjustment

[0014] Another known technology is the US Patent No. 6,853,563 "Primary-side controlled flyback power converter (Primary-side controlled flyback power converter)" proposed by Mr. Yang et al. One of the main shortcomings of this known technology It is Electromagnetic Interference (Electric and Magnetic Interference, EMI), which is caused by the fact that the drain of the switch is directly connected to the positive supply rail, so a parasitic capacitance of the switch is coupled with a parasitic inductance, thus forming a high-frequency resonance tank, so Will generate high electromagnetic interference

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