Inside the new device, highly accurate secondary-side direct voltage and current measurements are communicated across the safety isolation barrier using high-speed digital FluxLinkTM technology. This proprietary new feedback technique permits precise control without the need for a bulky optocoupler, while avoiding the performance compromises inherent in primary-side regulation (PSR), such as limited accuracy and efficiency and poor transient response versus no-load consumption.

Furthermore, unlike primary-side regulated switchers, InnoSwitch-based secondary-side regulated (SSR) designs are inherently less sensitive to the tolerance of external components such as transformers, diodes, resistors and capacitors. This dramatically increases manufacturing yield and reduces total power supply cost.

Now, mobile device chargers up to 5 A can have a total component count as low as PSR designs, with accurate CV and CC control (+/- 3% and +/- 5% respectively) and low voltage ripple. With high operating efficiency and <10 mW no-load consumption, the ICs easily comply with efficiency standards such as the California Energy Commission, European Union Code of Conduct (CoC) Version 5, Tier 2, and the upcoming US Department of Energy standards (DoE 6), which will become mandatory in February, 2016.

InnoSwitch power-supply ICs include a high-voltage power MOSFET, primary-side controller, FluxLink feedback technology and a secondary-side controller with synchronous rectification (SR). By combining the SR function with the secondary-side master controller and by leveraging the speed of the FluxLink communication channel, the SR switch timing is optimized for maximum efficiency.

The fast communication link also ensures highly reliable SR operation, eliminating shoot-through in either discontinuous conduction mode (DCM) or continuous conduction mode (CCM), even during transient loads and fault conditions. Effective SR operation in both DCM and CCM modes is especially beneficial in adaptive-voltage charger applications.

InnoSwitch ICs start up using bias current drawn from a high-voltage current source connected to the DRAIN pin, eliminating the need for external start-up components. An external bias winding reduces no-load and increases system efficiency during normal operation.

The ICs also include comprehensive system-level features such as output over-voltage protection, overload power limiting, hysteretic thermal protection and frequency jitter to reduce EMI.