This application guide introduces the LinkSwitch‑TN family, a non‑isolated power device that integrates a high‑voltage MOSFET switch with an on/off controller. It explains the device’s self‑powered operation, fault protection features, and suitability for a wide range of consumer‑grade applications such as household appliances, LED drivers, and night‑light circuits.
The document provides detailed circuit topologies (buck and buck‑boost), feedback options (direct and optocoupler), component‑selection tables, and design equations. It also compares continuous‑conduction (CCM) and discontinuous‑conduction (MDCM) modes, offering step‑by‑step procedures for selecting inductors, diodes, capacitors, and feedback networks to achieve target output voltage, current, and efficiency.
| Typical full‑load efficiency (12 V output) | >75 % |
|---|---|
| No‑load input power | <100 mW |
| Auto‑restart support | LNK304‑306 only |
| Minimum load for direct‑feedback operation | 3 mA |
The circuit requires at least a 3 mA load to maintain regulation.
Auto‑restart is available on the LNK304 and LNK306 devices.
Typical full‑load efficiency exceeds 75 % for a 12 V output.