anticache

Characterization and Implementation of a power consumption measurement and profiling circuit (Abschlusskolloquium )

25.10.2011

Khaled Kombas


Abstract:

Texas Instrument's MSP430 micro-controllers are optimized for ultra low power applications through their different low power operation modes. They have several power states with different power consumptions adjusted to different operation modes. Accurately determining how much power is being drawn by the micro-controller and its peripherals in different power states, requires a precise dynamic system, which can keep track of the real-time power consumption of the micro-controller. In this thesis a profiling solution was developed to sense the current consumption of MSP430 micro-controllers. The goal was to sense currents ranging from 0,1µA to 100mA with a measurement bandwidth of 10kHz and a budget limitation of 7$ in terms of bill of material. The current profiling circuit was intended to be integrated into the debugging interface and to be usable for all MSP430 generations. The circuit implemented in this thesis is based on resistive current sensing. It consists of a shunt resistor within the supply line of the MSP430 and a unit measuring the voltage drop across it. Simulation data in combination with measurement results have shown a trade-of between the measurement bandwidth and the lowest current that can be sensed: the higher the bandwidth, the more difficult it becomes to sense very tiny currents and vice versa. The designed circuit is capable of measuring currents in the range of 1µA to 50µA with a maximum bandwidth of 5kHz and currents ranging from 50µA to 100mA with a dynamic of 8kHz