EET 422 EMC COMPLIANCE ENGINEERING 1 2 SMPS

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EET 422 EMC & COMPLIANCE ENGINEERING 1

EET 422 EMC & COMPLIANCE ENGINEERING 1

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SMPS DISTURBANCES 3

SMPS DISTURBANCES 3

IDS= IDM IDS Cp ICM IDS 0 VDS 0 ICM 0 4

IDS= IDM IDS Cp ICM IDS 0 VDS 0 ICM 0 4

INSULATION ~ C M NOISE PATHWAY = ICM 5

INSULATION ~ C M NOISE PATHWAY = ICM 5

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DIFFERENTIAL MODE INTERFERENCE 7

DIFFERENTIAL MODE INTERFERENCE 7

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COMMON MODE INTERFERENCE 9

COMMON MODE INTERFERENCE 9

FLYBACK SMPS CCM DCM 10

FLYBACK SMPS CCM DCM 10

10 m. V : Excellent 100 m. V : Average 1 V : Excessive

10 m. V : Excellent 100 m. V : Average 1 V : Excessive 11

SMPS CONDUCTED EMISSIONS 12

SMPS CONDUCTED EMISSIONS 12

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‘INTRINSIC’ DIFFERENTIAL MODE NOISE es. L L C N esr S IDS S o

‘INTRINSIC’ DIFFERENTIAL MODE NOISE es. L L C N esr S IDS S o IDS(AC) G o LISN XC 2 k. W @ 1 MHz XC 2 MW @ 10 k. Hz DM noise normally due to SMPS pulsating current ac component LISN presents 100 W impedance (2 series 50 W) if capacitor esl significant then HF DM source RECTIFIER ‘ON’ HIGHER DM 15

‘INTRINSIC’ DIFFERENTIAL MODE NOISE es. L L C N esr S IDS S o

‘INTRINSIC’ DIFFERENTIAL MODE NOISE es. L L C N esr S IDS S o IDS(AC) G o LISN XC 2 k. W @ 1 MHz XC 2 MW @ 10 k. Hz DM noise normally due to SMPS pulsating current ac component LISN presents 100 W impedance (2 series 50 W) if capacitor esl significant then HF DM source RECTIFIER ‘ON’ HIGHER DM 16

LISN L L CS Cn Cm R Rm L G CS N L Cm

LISN L L CS Cn Cm R Rm L G CS N L Cm R N Rmm IDM Cn G G ANALYSER 17

LISN L L CS Cn Cm R Rm L G CS N L Cm

LISN L L CS Cn Cm R Rm L G CS N L Cm R N Rmm IDM Cn G G ANALYSER 18

COMMON MODE NOISE: MOSFET TURNING ON es. L L C N esr P P

COMMON MODE NOISE: MOSFET TURNING ON es. L L C N esr P P IDS o IDS(AC) o G LISN VDS o XC @ 2 k. W @ 1 MHz XC @ 2 MW @ 10 k. Hz CM noise normally due to SMPS parasitic capacitance and LISN presents 25 W impedance (2 parallel 50 W) 19

COMMON MODE NOISE: MOSFET TURNING ON es. L L C N esr P P

COMMON MODE NOISE: MOSFET TURNING ON es. L L C N esr P P IDS o IDS(AC) o G LISN VDS o XC @ 2 k. W @ 1 MHz XC @ 2 MW @ 10 k. Hz CM noise normally due to SMPS parasitic capacitance and LISN presents 25 W impedance (2 parallel 50 W) 20

LISN L L CS Cn Cm R Rm L G CS N L N

LISN L L CS Cn Cm R Rm L G CS N L N Rm R ICM, L C ICM, N Cn G G ICM, L+ ICM, N ANALYSER 21

LISN L L CS Cn Cm R Rm L G CS N L N

LISN L L CS Cn Cm R Rm L G CS N L N Rm R ICM, L C ICM, N Cn G G ICM, L+ ICM, N ANALYSER 22

COMMON MODE NOISE: MOSFET TURNING OFF es. L L C N esr P P

COMMON MODE NOISE: MOSFET TURNING OFF es. L L C N esr P P IDS o IDS(AC) o G LISN VDS XC 2 k. W @ 1 MHz XC 2 MW @ 10 k. Hz o CM noise normally due to SMPS parasitic capacitance and LISN presents 25 W impedance (2 parallel 50 W) 23

COMMON MODE NOISE: MOSFET TURNING OFF es. L L C N esr P P

COMMON MODE NOISE: MOSFET TURNING OFF es. L L C N esr P P IDS o IDS(AC) o G LISN VDS XC 2 k. W @ 1 MHz XC 2 MW @ 10 k. Hz o CM noise normally due to SMPS parasitic capacitance and LISN presents 25 W impedance (2 parallel 50 W) 24

LISN L L CS Cn Cm R Rm L G N CS R Cm

LISN L L CS Cn Cm R Rm L G N CS R Cm Rm ICM, L C ICM, N Cn N L G G ICM, L+ ICM, N ANALYSER 25

COMMON MODE NOISE: PARASITIC CAPACITANCE es. L L C N esr P P IDS

COMMON MODE NOISE: PARASITIC CAPACITANCE es. L L C N esr P P IDS o IDS(AC) o G LISN VDS o XC 2 k. W @ 1 MHz XC 2 MW @ 10 k. Hz CM noise normally due to SMPS parasitic capacitance and LISN presents 25 W impedance (2 parallel 50 W) 26

SMPS: INPUT FILTER 27

SMPS: INPUT FILTER 27

SMPS: NO INPUT FILTER 28

SMPS: NO INPUT FILTER 28