The RDK-866 reference design describes a non-isolated buck converter power supply with an input-line zero-crossing detection output signal. The nominal output is 5 V/500 mA across the input range of 90 V to 300 V ac.
The system is powered by the LinkSwitch-TNZ IC controller. The LinkSwitch-TNZ family of ICs combines power conversion with lossless generation of an ac zero-crossing signal used typically for system clock and timing functions. The device incorporates a 725 V power MOSFET, oscillator, a high-voltage switched current source for self-biasing, frequency jittering, fast (cycle-by-cycle) current limit, hysteretic thermal shutdown, and output and input overvoltage protection circuitry in a monolithic IC.
Designs using the highly integrated LinkSwitch-TNZ ICs are more flexible than discrete implementations, reducing component count by 40% or more. The key design goal is low cost, low audible noise and compact form factor for use in wireless and relay power supplies.