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Power Adapter Safety And Electromagnetic Compatibility

Shenzhen GEO Technology Co.,Ltd | Updated: Oct 19, 2017

Power adapter safety and EMC electromagnetic compatibility, for the industry that is "well-known", but for the vast number of consumers may be relatively unfamiliar, and we as a senior power adapter manufacturers, today to give you Explain, so that we can better understand the power adapter:

Safety regulations (GB 4943-2001)

First, the insulation space requirements. UL, CSA, VDE safety specifications emphasize the distance between the live parts and the surface and space between the live and non-charged metal parts. UL, CSA requirements: between the voltage between 250VAC high voltage conductors, and between the high voltage conductor and non-charged metal parts (not including the wire between), whether in the surface or in space, should be 0.1 inches distance VDE requires a 3mm creep or 2mm net clearance between the AC lines. IEC Requirements: There is a clearance clearance of 3mm between the AC line and a 4mm clearance clearance between the AC line and the ground conductor. In addition, VDE, IEC requirements in the power output and input between, at least 8mm space spacing.

Second, the leakage current. The leakage current is the current flowing through the input side of the ground, in the switching power supply is mainly through the squelch filter bypass capacitor leakage current. UL, CSA are required to expose the non-charged metal parts should be connected with the earth, leakage current measurement is through these parts and the earth between a 1.5K ohm resistance, the leakage current should not be greater than 5 mA. VDE allows: with 1.5K ohm resistor and 150nP capacitor and then. Power adapter And the application of 1.06 times the rated voltage, the data processing equipment, leakage current should not be greater than 3.5 mA. Usually about 1 mA.

EMC Electromagnetic Compatibility (GB9254-1998)

The electromagnetic compatibility of the power supply is divided into electromagnetic sensitivity and conducted radiation harassment.

First, the capacitive compatibility

1. Magnetic field sensitivity: (immunity) The degree of unwanted response of the device, sub-system or system to exposure to electromagnetic radiation. The smaller the sensitivity level, the higher the sensitivity, the worse the immunity. Power adapter Fixed frequency, peak-to-peak magnetic field.

2. Electrostatic Discharge Sensitivity: Charge transfer with objects with different electrostatic potentials that are close to or in direct contact with each other. 300PF capacitor charge to -15000V, through the 500 ohm resistor discharge. Can be poor, but after the release to normal. Data transfer, storage, can not be lost

3. Power Transient Sensitivity: Includes spike signal sensitivity (0.5us 10us 2x), voltage transient sensitivity (10% -30%, 30S recovery), Power adapter frequency transient sensitivity (5% -10%, 30S restore).

4. Radiation Sensitivity: A measure of the radiation interference field that causes degradation of the equipment. (14K-1GHZ, electric field strength of 1V / M).

5. Conductivity Sensitivity: A measure of the interference signal or voltage on the power supply, control, or signal line when the device is unwanted to respond or cause degradation of its performance. (30HZ-50KHZ 3V, 50K-400M 1V).

6. Non-working state Magnetic field interference: Packing box 4.6m Magnetic flux density less than 0.525uT, 0.9m 0.525Ut.

7. Working state magnetic field interference: upper, lower, left and right AC magnetic flux density less than 0.5mT. 2, conduction interference: interference along the conductor transmission. 10KHz-30MHz 60 (48) dBuV.

Second, the radiation interference: Power adapter through the space in the form of electromagnetic waves to spread the electromagnetic interference. 10KHz-1000MHz 30 shielded room 60 (54) uV / m.