DC-DC converter-aware power management for battery-operated embedded systems

ABSTRACT

Most digital systems are equipped with DC-DC converters to supply various levels of voltages from batteries to logic devices. DCDC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of DC-DC converters is changed by the output voltage level and the load current, most existing power management techniques simply ignore the efficiency variation of DC-DC converters. However, without a careful consideration of the efficiency variation of DC-DC converters, finding a true optimal power management will be impossible. In this work, we solve the problem of energy minimization with the consideration of the characteristics of power consumption of DC-DC converter. Specifically, the contributions of our work are: (1) We analyze the effects of the efficiency variation of DC-DC converters on a single task execution in DVS (dynamic voltage scaling) scheme, and propose a technique, called DC_DVS, of DC-DC converter-aware energy-minimal DVS; (2) DC_DVS is then extended to combine the effects of DC-DC converters with the procedures of general DVS techniques with multiple tasks; (3) Conversely, we propose a technique, called DC_CONF, of generating a DC-DC converter that is best suited, in terms of total energy efficiency, to the intended application, and (4) finally, we complete our integrated framework DC-lp, which is based on DC_DVS and DC_CONF, that attempts to solve the DC-DC converter configuration selection problem and the DVS problem simultaneously. To show the effectiveness of the proposed techniques, a set of experimental results is provided. In summary, it is shown that DC-lp is able to save 16.0%~22.1% of energy on the average, which otherwise was dissipated in the previous power management schemes with no consideration of DC-DC converter efficiency variation.

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.8 Performance and Reliability
      B.8.2 Performance Analysis and Design Aids

Additional Classification:
  C. Computer Systems Organization
  C.4 PERFORMANCE OF SYSTEMS

General Terms:
Design, Performance

Keywords:
DC-DC converter, low power, voltage scaling