Circuit design of 0.75W tamper-proof meter power supply

MOS power IC full range

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

inductance

SMD aluminum electrolytic capacitor

Summary:

The tamper-proof meter power supply circuit design uses the LNK363DN to generate an isolated output of 5 V and 150 mA. The transformer designed here has sufficient inductance to enable the power supply to provide the required power. Even if someone uses a strong external magnetic field to saturate the core in an attempt to tamper with the meter, the power supply will not be affected.

Tamper-proof meter power supply design features

• Low cost and low component count
• Enhanced tamper-proof protection with iron powder core material
• Can still work normally under the interference of external magnetic field
• Low working flux density (400 Gauss), reduced core loss (<40 mW)
• High efficiency (up to 58% at full load)
• Efficient use of the available power at the input (the limit of the IEC10362 standard is 2 W, 10 VA)
• Fully extend the maintenance time
• The time-consuming electrical energy is stored in the input capacitor
• No need for large output capacitors or a second higher output voltage
• Conforms to EN55022B conducted EMI limits, EMI margin >6 dBmV

Circuit diagram of 0.75W tamper-proof meter power supply

See the uploading documentation for details (click to download)