This document describes a 1.6W linear replacement adapter with a 10kV surge withstand specification and an 85-265VAC input, 7.7V, 210mA output. The adapter features a highly efficient and low-cost switching solution, serving as a replacement for existing AC line transformer-based designs. It is designed to withstand 10kV common-mode surges and is ideal for applications connected to the telephone network. Additionally, the adapter is EcoSmart® compliant, meeting all existing and proposed harmonized energy efficiency standards. It has a no-load power consumption of less than 220mW at 265VAC and an active-mode efficiency of 61.3%, exceeding the requirement of 53.2%. The integrated LinkSwitch safety/reliability features include accurate and auto-recovering thermal shutdown function, ensuring safe PCB temperatures under all conditions, and auto-restart protection against output short circuits and open feedback loops. The adapter also meets EN55022 and CISPR-22 Class B conducted EMI with a margin of over 15 dBµV and IEC61000-4-5 Class 4 AC line surge requirement.
This document describes a switched‑mode power supply designed to replace traditional line‑frequency transformer adapters. It uses a Power Integrations LinkSwitch‑LP IC and is capable of withstanding up to 10 kV common‑mode surges, making it suitable for telephone‑line applications such as cordless phones.
The report includes specifications, schematic, PCB layout, bill of materials, transformer details, performance data, thermal performance, waveforms, and EMI compliance information. It also outlines safety features like hysteretic thermal shutdown and auto‑restart functions.
| Input Voltage | 85‑265 VAC |
|---|---|
| Input Frequency | 47‑64 Hz |
| No‑load Input Power (230 VAC) | 0.3 W |
| Output Voltage | 6.7‑7.7‑8.7 V |
| Output Ripple Voltage | 400 mV (20 MHz bandwidth) |
| Output Current | 0.21 A |
| Continuous Output Power | 1.4‑1.6 W |
| Full‑load Efficiency | 60 % |
| Required Average Efficiency | 53 % |
| Conducted EMI Compliance | Meets CISPR22B / EN55022B |
| Safety Standard | UL1950 |
| Common‑mode Surge Immunity | 10 kV |
| Ambient Temperature Range | Up to 50 °C |
The design is rated to survive common‑mode line surges of up to 10 kV.
The worst‑case no‑load power consumption is about 200 mW at 265 VAC (below 220 mW).
Full‑load efficiency is measured at 60 % (at 25 °C).
Yes, it meets CISPR‑22B / EN‑55022B conducted EMI limits with more than 15 dBµV margin.