Power Integrations (Nasdaq: POWI), a well-known company in the field of high-voltage integrated circuit high-efficiency power conversion, recently announced the launch of a new switching power supply IC product – LinkSwitch™-TNZ, which is a high-efficiency switching power supply IC in Off-line power conversion, lossless zero-crossing detection, and optional X-capacitor discharge are integrated into a compact SO-8C package for non-isolated buck and buck-boost power supply applications with output currents up to 575mA. With an isolated flyback design, it can deliver up to 12W of output power at universal input voltage.

Adnaan Lokhandwala, Product Marketing Manager at Power Integrations, said: “The new LinkSwitch-TNZ ICs provide precise indications of sinusoidal AC input voltages of zero volts. These signals are used in smart home and smart building (HBA) products and appliance applications. Controls switching of relays, IGBTs and TRIACs to reduce switching stress and system inrush current. LinkSwitch-TNZ consumes less than 5mW at zero-crossing detection, unlike those that require ten or more discrete components and consume 50-100mW of continuous power The LinkSwitch-TNZ IC saves more standby power compared to the method”

Devices such as light switches, dimmers, sensors, and plugs use relays or thyristors to periodically connect and disconnect from AC lines. Usually a discrete circuit is required to detect the zero-crossing point of the AC input to control the access switching of the main power device, while reducing switching losses and inrush current. But this approach requires a lot of components and is very lossy, consuming almost half of the standby power budget in some cases. Likewise, home appliances often use discrete zero-crossing detection circuits to control motor and microcontroller timing. These applications also require auxiliary power to power functions such as wireless connectivity, gate drivers, sensors, and displays.

LinkSwitch-TNZ ICs provide best-in-class light-load efficiency, enabling more system functions to be powered while meeting stringent standby standards. For example, the European Commission’s (EC) Home Appliances Standard (1275) requires devices to consume no more than 0.5W in standby or off mode; ENERGY STAR’s version 1.1 Smart Home Energy Management System (SHEMS) standard incorporates smart lighting controls The standby power consumption of the device is limited to less than 0.5W; while China’s national standard GB24849 requires that the power consumption of the microwave oven in shutdown mode be limited to less than 0.5W. Compared with discrete component designs, the LinkSwitch-TNZ solution can reduce the component count by more than 40%.

In addition, for high-power applications, the X capacitor discharge function in the product (LNK331x) package can be used to reduce the PCB footprint, reduce the number of BOM components and improve reliability.

LinkSwitch-TNZ switching power supply ICs provide ±3% regulation accuracy over a wide range of input voltages and loads, with no-load power consumption below 30mW when using external bias, and IC standby current below 100µA. The new device solution is simple to use, has an integrated soft-start function, and is suitable for both isolated and non-isolated topologies.

Supply and related resources

The LinkSwitch-TNZ switching power supply IC is priced at $0.84 per piece based on 1000-piece bulk purchases. There are four reference design examples available for download in the package. The DER-874 and RDR-866 are non-isolated step-down designs that provide 6V/80mA output and 5V/500mA output, respectively. The RDR-877 is an isolated flyback power supply with a secondary-side zero-crossing (ZCD) signal detection function that provides 12V/0.5A output, while the DER-879 is a ZCD function and an integrated X-capacitor discharge circuit that provides Isolated flyback power supplies with 12V/0.75A and 5V/0.2A outputs.