With InnoSwitch ICs, designers can easily exceed all global standards for efficiency and no-load power consumption, while minimizing the number of components and providing high-precision constant voltage and constant current up to 25 W. The InnoSwitch family is ideal for smart mobile device chargers and adapters for a wide range of applications such as set-top boxes, networking equipment, and computer peripherals.
Inside the new device, high-precision secondary-side DC voltage and current measurements are communicated across the safety isolation barrier using high-speed digital FluxLink™ technology. This new, patented feedback technique enables precise control without the need for an optocoupler, while avoiding the compromised performance inherent in primary-side regulation (PSR), such as limited accuracy and efficiency, and poor transient response against no-load consumption. Furthermore, unlike primary-side regulated switches, 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 increases manufacturing efficiency and reduces the overall cost of the power supply. Now, mobile device chargers up to 5 A can have a total component count comparable to PSR designs, with precise CV and DC control (+/- 3% and +/- 5%, respectively) and low voltage ripple. With high operating efficiency and <10 mW no-load consumption, the integrated circuits easily meet efficiency standards such as those of the California Energy Commission, the European Code of Conduct (CoC) Version 5, Tier 2, and the upcoming US Department of Energy (DoE 6) regulations, which will be mandatory in February 2016.
InnoSwitch power supply ICs include a high-voltage MOSFET, a 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 leveraging the speed of the FluxLink communication channel, the SR timing switch 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 particularly beneficial in adaptive voltage load 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 startup components. An external bias winding reduces no-load current and increases system efficiency during normal operation. The integrated circuits also include comprehensive system-level features such as overvoltage protection, overload power limiting, thermal hysteresis protection, and frequency jitter protection to reduce EMI.
InnoSwitch-CH, optimized for chargers, are the first devices in the family, and samples are available now. InnoSwitch-CH ICs are priced from $0.59 to $0.78 in quantities of 10,000 pieces. Reference design RDR-420 describes a 5V, 2A USB charger design.
