Linear power baseband controller offers cost-down design

The RT9641A/B from RichTek Technology Corp is a triple linear regulator/controller designed to support the ACPI (advanced configuration and power interface) control interface in µP and system applications. It supports the configuration of IAPC (instantly available PC), which enables immediate wake-up by a system that has been suspended to power-saving mode. On wake-up, the previous system state and parameters are restored. In this regard, the controller enables seamless mode transitions, guarding against data and parameter loss.

The RT9641A controls and regulates three power branches, including a 5-V system output (5-V dual), a 3.3-V system output (3.3-V dual), and a selectable 3.3-/2.5-V memory power output (Vmem), where each of the three output power branches can be fed from two power sources. Individual on/off control for 5-V dual and 3.3-V dual provides a high degree of flexibility, supporting a variety of system requirements.

In operation, the RT9641A/B performs seamless switching between power sources, according to the mode of operation, as indicated by signals S3# and S5#, power source availability, and transition delay as set by an external capacitor. As noted, the controller has been designed for seamless transitions between operational modes, in order to prevent data loss.

In addition to supervising the three power output branches, this controller also monitors chip temperature and will flag system overload and overheating. It then waits for a signal for power-down, followed by a reset. It should be noted that error detection is not followed by an immediate power down since this could lead to data loss. Nevertheless, the controller will proceed to shut down if there continues to be a rise in temperature without a response from the system.

The RT9641B differs from the RT9641A in the selectable Vmem, which in the case of the B part is 3.43-/2.6-V, in order to overdrive system memory. In active mode, the controller can detect what types of external power device are connected. It can, for instance, distinguish between a bipolar transistor and a MOS transistor, and the controller is then configured for the optimal driving scheme. Memory operation is crucial to system ability, and this design ensures effective regulation of Vmem and good transient response.

This controller is available in a 16-pin SOIC package. In conjunction with four to five low-cost external power devices, it supports full ACPI functionality, including active mode (S0), suspend-to-RAM (S3), and suspend-to-disk (S5).


Richtek Technology Corp
Fax (886) 3-552-6611
www.richtek-ic.com.tw