Another app note from Richtek introducing solutions for reducing the input voltage spike on power switches. Link here
The power switch is a low voltage, single N-Channel MOSFET high-side power switch, optimized for self-powered and bus- powered Universal Serial Bus (USB) applications.
In worse operating condition, an input voltage spike may over the chip’s maximum input voltage specification to damage the chip.
Investigative app note from Richtek about the component failure point caused by EOS. Link here (PDF)
Failures in power ICs are often the result of Electrical Over Stress (EOS) on the IC input supply pin. This report explains the structure of power IC input ESD protection and how ESD cells can become damaged due to EOS. Common causes for input EOS are hot-plug events and other transient effects involving wire or trace inductance in combination with low ESR ceramic capacitors. Solutions are presented how to avoid EOS via special circuit and system design considerations.
Another app note from Richtek, this time about transient load testing on power converters and how you can make a simple and low cost fast transient tool. Link here (PDF)
Load transient testing is a quick way to check power converter behavior on several aspects: It will show the converter regulation speed and can highlight loop stability problems. Other power converter aspects like input voltage stability, slope compensation issues and layout problems can be quickly spotted as well. This application note will explain the practical use of load transient testing to diagnose DC/DC power converter problems.
An application note from Richtek on buck converter used in automotive application. Link here (PDF)
Automotive environment can be quite harsh and designing electronics that need to work reliable in this environment takes special care, and often requires automotive qualified parts.
When designing voltage regulators that need to step down an intermediate voltage from the car battery supply, the car battery voltage fluctuation needs to be taken into regard.
The full operating temperature range needs to be considered for all aspects of the design, and all component parameters have to be checked over temperature.
The car radio receiver is nearby, which means that any switch-mode converter radiated emission needs to be minimized to avoid switch noise being coupled into the car radio receiver.
More Li-ion battery applications from Richtek. Link here (PDF)
Lithium-Ion batteries have several advantages when compared with other battery types: They are light weight, and energy density of lithium-ion is typically twice that of the standard nickel-cadmium. Li-Ion batteries have no memory effect, and the self-discharge is 6 ~ 8 times less compared to nickel-cadmium. The high cell voltage of 3.6 volts is often sufficient to power applications from a single cell. These properties make Li-Ion batteries very popular in modern portable electronic applications.
App note from Richtek about several aspects of switching chargers for single cell Li-Ion batteries. Link here (PDF)
Longer battery life and shorter charging times are some of the challenges in battery management in modern hand-held applications like Smart-Phones, Tablet PCs, POS and other portable equipment.
Devices with powerful processors are more power hungry and require larger capacity batteries to guarantee battery life. To quickly charge large capacity batteries, powerful high current chargers are needed. Linear chargers have too limited charge current capability for this purpose, so switching charger topology has to be adopted.