Block Diagram
The block diagram in Figure illustrates an intermediate-complexity, space-efficient application example that demonstrates the functionalities required by many battery-operated devices powered by a standard 5V USB. The MCP73833/4 charges the battery and supplies voltage to the MCP16501/2 PMIC.
At this stage, it may be necessary to include an additional System Power Path Management block, which should be integrated into the final application for certain use cases. As previously mentioned, in case the application needs to run while the battery needs to charge, the charge termination may never be reached because the load current exceeds the charge termination current. In this case, a timer fault will be generated and, to fully charge the battery, additional steps such as removing and reinserting the battery, power cycling the device, or setting the PROG pin to High-Z state. Fortunately, the MCP73834 option offers a Timer Enable Input (instead of the Power Good pin) that can be used to disable the timer when the charger is supplying current to charge the battery and power the system load. In case the MCP73833 is required due to the functionality of the Power Good output, there is already a workaround for this issue explained in a document called “MCP7383X Li-Ion System Power Path Management Reference Design”. This document shows how the System Power Path Management allows end-users to charge their batteries without interruption just by adding a few additional components in the final application.
The PMIC generates the necessary voltage rails and provide an interface to the MPU. Additionally, the PMIC offers power sequencing and voltage programmability, allowing for adjustments in response to various power-saving or performance-enhancing operating modes. It also monitors and controls incoming and outgoing voltage and current, as well as thermal limits during operation, and signals components to respond to any faulty conditions. MCP73833/4 has two status indicators that can be used to illuminate LEDs or can be used as an interface to a host microcontroller.
