List of figures

AN1714

4/46

List of figures

Figure 1.

Typical powerline modem applications scenario. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 2.

Mains signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 3.

Aggregate European powerline impedance (by Malack and Engstrom). . . . . . . . . . . . . . . . 7

Figure 4.

Voltage spectra of a 100 W light dimmer, a notebook PC, a desktop PC, a CFL lamp,

a TLE lamp, all working with a 50 Hz/~220 V supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 5.

FSK modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 6.

ST7538Q transceiver block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 7.

ST7538Q demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 8.

Demonstration board layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 9.

Demonstration board schematic: microcontroller and PC interface . . . . . . . . . . . . . . . . . . 12

Figure 10.

Demonstration board schematic: line coupling interface and power supply . . . . . . . . . . . . 13

Figure 11.

Demonstration board ST7538Q powerline interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 12.

Demonstration board ST7538Q transmission coupling circuit . . . . . . . . . . . . . . . . . . . . . . 15

Figure 13.

Simplified schematic of the transmission filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 14.

Simulated characteristics of the transmission coupling filter. . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 15.

Figure 16.

Demonstration board ST7538Q receiving circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 17.

Measured filtering characteristic of the demonstration board at the RAI pin in receive

mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 18.

Powerline output characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 19.

Voltage regulation and current protection components . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 20.

Voltage regulation/current protection loop logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 21.

Current protection loop characteristic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 22.

Voltage regulation and current protection feedback signals . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 23.

Power supply EMC disturbances filter circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 24.

Noise generation in resistive supply or ground path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 25.

A recommended oscillator section layout for noise shielding . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 26.

Common mode and differential mode spikes example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 27.

Microcontroller/RS232 interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 28.

ST7538Q / microcontroller interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 29.

Conducted disturbance setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 30.

Output signal spectrum, channel 132.5 kHz, mains 220 V~, fixed tone . . . . . . . . . . . . . . . 38

Figure 31.

Output signal spectrum, channel 132.5 kHz, mains 220 V~, random sequence . . . . . . . . 38

Figure 32.

Output signal spectrum, channel 132.5 kHz, mains 110 V~, random sequence . . . . . . . . 39

Figure 33.

Output signal spectrum, channel 110 kHz, mains 220 V~, random sequence . . . . . . . . . . 39

Figure 34.

Narrowband conducted interferences setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 35.

Signal/noise ratio for the 132.5 kHz channel, signal level 85 dBuV . . . . . . . . . . . . . . . . . . 40

Figure 36.

Signal/noise ratio for the 132.5 kHz channel, signal level 85 dBuV, mains 110 V~ . . . . . . 41

Figure 37.

Signal/noise ratio for the 110 kHz channel, signal level 91 dBuV. . . . . . . . . . . . . . . . . . . . 41

Figure 38.

Output board impedance measurement setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 39.

Output demonstration board impedances (CN1) in receiving condition . . . . . . . . . . . . . . . 42

Figure 40.

Output demonstration board impedances (CN1) in transmitting condition . . . . . . . . . . . . . 42

Figure 41.

Zero-crossing coupling circuit, nonisolated solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Figure 42.

Zero-crossing coupling circuit, isolated solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43