“The practical aspects of utilizing Digital Power Controller for monitoring of power supply operation”

Utilization of digital control in the design of power controllers provides designers with the capability to monitor multiple operational parameters of a power converter. This functionality is often harder to achieve with converter designs based on analog controllers. The reason for this difference is that the information used for internal control purposes in the case of a digital controller is digitized, and thus is readily available for reading by an external device. In the case of an analog controller, this is not the case, so achieving monitoring and measurement functionality with an analog controller requires significant increases in system complexity. Monitor and measurement capabilities are in many cases very much welcomed by both power and system designers. To be able to fully utilize this functionality, however, and to be able to realize reliable results from measurements made internally by the controller poses a set of complex challenges that most of engineers who design power converters have little familiarity with. The purpose of this paper is to review some of the measurement techniques, the design considerations involved in the utilization of these techniques, and also to assess what are reasonable expectations for the accuracy of such measurements. To achieve this goal we are going to review examples of how Input Voltage, Output Voltage, Output Current and Temperature sensing are implemented, as well as the influence of external components, board layout and operating range on the results of such measurements. We are also going to review what kind of information from the controller IC manufacturer is required to properly realize the maximum achievable accuracy of readings for a specific design.