Debugging item: space radiation

Countermeasure analysis and solution description

1. Contact a small ferrite bead in series at each pin of MOS tube, bridge rectifier and diode.

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2. Change the filtering circuit of input end to the combinating filtering consisting of 1uF X capacitor + 35mH common mode inductor + 1uF X capacitor + 35mH                common mode inductor. And  add a ferrite core to AC wire, winding 8 turns(L/N/G be wound parallel.)

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3. Parallel a 102 ceramic flat capacitor to S/D pin of both Q18 and Q19. 

    Parellel a 101 ceramic flat capacitor to S/D pin of switch MOS and adjust its drive resistor as 68ohm.

    After rectification, add a π type filtering circuit, consisting of CBB224 capacitor + 200uH differential inductor + CBB224 capacitor

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4. Shield L2 with copper foil in both tansversal and longitudinal directions, and link it to earth.

    Add a 102 capacitor between output positive end and earth, and a 104 capacitor between negative end and earth.

    Contact a BEAD1812S90T ferrite bead in series to every positive pole shown below of the power. 

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5. Contact a BEAD1812S121A90T ferrite bead in series to both two poles of output.

    Contact a BEAD1812S121A90T ferrite bead in series to both input and output pins of IC shown in the picture.

    Contact a BEAD1812S121A90T ferrite bead in series to output pins of the two inductors.

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6. Add a small ferrite core to both ends of the three jumper wires of output.

Testing data of conduction

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