Switcher ICs from Power Integrations up efficiency while reducing component count
June 30, 2021
Power Integrations has upped the game in the switching power-supply space with the release of its LinkSwitch-TNZ ICs. The devices combine offline power conversion, lossless zero-cross detection and, optionally, X-capacitor discharge functions, all in a compact SO-8C package. The parts can be used for non-isolated buck and buck-boost power supplies with an output current of up to 575 mA and can provide up to 12 W output for universal-input isolated flyback designs. These are specs that are suited for smart home and appliance applications.
The goal is to provide an accurate signal indicating that the sinusoidal AC line is at 0 V, a signal that’s used to control the switching of relays, IGBTs, and TRIACs to minimize switching stress and system in-rush current. LinkSwitch-TNZ’s detection of the zero-cross point consumes less than 5 mW, reducing standby power losses versus alternative approaches.
The LinkSwitch-TNZ switching power supply ICs enable ±3% regulation across line and load, no-load consumption of less than 30 mW with external bias and have an IC standby current of less than 100 µA. Its feature set also adheres to most global regulatory guidelines.
The parts sell for $ 0.84 each in lots of one thousand. Four reference designs are available for download. DER-874 and RDR-866 are non-isolated buck designs delivering 6V/80mA output and 5V/500mA output respectively. RDR-877 describes a 12V/0.5A output isolated flyback with secondary-side ZCD signal, while DER-879 describes a 12V/0.75A and 5V/0.2A isolated flyback with ZCD and integrated X-capacitor discharge circuitry.