Power Consumption Reduction Technology in Multifunction Device Controllers

As awareness of environmental issues continues to grow, so too does the demand for reduced power consumption and lower CO2 emissions in office multifunction devices. In order to satisfy this demand, multifunction devices are equipped with a sleep mode designed to reduce the amount of electricity consumed during standby. However, even while in sleep mode, the controller of a multifunction device can never be completely switched off. Governing the entire machine, the controller must remain ready to quickly process requests for printing, job monitoring, and status confirmation from networked host PCs.

A leader in the industry: reducing power consumption in sleep mode to 0.5 WAC (CPFS)Note 1

Within the controller circuit configuration, one particularly heavy consumer of power is the CPU. Fuji Xerox, targeting its efforts to reduce power use in this area, succeeded in developing a circuit configuration capable of swiftly waking from sleep mode to deliver required responses to processing requests sent in from networked host PCs even when the CPU power is off. This quick response time is made possible by the functions of (1) high-speed CPU recovery and (2) storage of communication packets in the controller memory (see Fig. 1), both of which are implemented into the controller as part of the control circuit.

In addition to these advancements, the refinement of the nanofabrication manufacturing process of the SoCNote 2 semi-conductor chip used in the controller has allowed for reductions in SoC voltage. Furthermore, power-gating has been employed in the SoC power supply block, meaning that when in sleep mode, distribution of power is limited to the power management circuit and network interface circuit. These developments have allowed for optimal control over device power, as well as simultaneously delivering enhanced network performance and compliance with power-saving network standards.

Fig. 1: Overview of power consumption reduction technology used in the controller

The result of these technological achievements is a sleep mode power consumption of 0.5 WAC (CPFS)—a 52% reduction from that of its predecessor and one of the smallest power footprints in the industry.

  • Note 1 CPFS: models equipped with copy, print, fax, and scan functions.
  • Note 2 SoC (System-on-a-Chip): a circuit that integrates all the necessary components (system) into a single semiconductor chip.