Abstract: A digital signal voting circuit (10) is described for each module in a modular uninterruptible power supply (UPS) in which a plurality of modules are connected in parallel. The voting circuit (10) includes a first comparator (14) for comparing a decision output signal of the voting circuit, and the cumulative effect of the decision output signals of the voting circuits in parallel modules, with a reference threshold signal (VREF). Comparator (14) generates a first comparison result signal when the decision output signal (D) is greater than the reference threshold signal (VREF). Logic element (12) has two inputs, one of which is fed with a control signal (A1) from the module and a second input which receives an output signal (A2) from the first comparator (14). When the output signal (A3) of logic element (12) is low, it will go high when either one of the input signals (A1 or A2) goes high.

Abstract: A digital signal voting circuit (10) is described for each module in a modular uninterruptible power supply (UPS) in which a plurality of modules are connected in parallel The voting circuit (10) includes a first comparator (14) for comparing a decision output signal of the Voting circuit, and the cumulative effect of the decision output signals of the voting circuits in parallel modules with a reference threshold signal (VREF). Comparator (14) generates a first comparison result signal when the decision output signal (D) is greater than the reference threshold signal (VREF) Logic element (12) has two inputs, one of which is fed with a control signal (A1) from the module and a second input which receives an output signal (A2) from the first comparator (14). When the output signal (A3) of logic element (12) is low, it will go high when either one of the input signals (A1 or A2) goes high.

Abstract: An expandable power connector module in the form of a modular power board or modular power strip 10 is described. The modular power board 10 includes a plurality of power sockets 12 provided on a base structure 14, each of the power sockets being connected to a power cord 16 for connection to a mains supply power outlet. The base structure 14 is designed to connect to one or more additional power modules and is provided with snap-on connectors 20 for physically connecting the base structure to a second power board 22. In this way, the function of the power board can be expanded to provide additional power connection and/or power conditioning features by connecting one or more additional power modules. The base structures 14 and 26 are also provided with electrical connectors for electrically connecting each of the power sockets 12 on the second power board 22 with the power cord 16 of the first power board 10.

Abstract: An uninterruptible power supply (UPS) device 10 is described having only half the number of inductors and storage capacitors of a conventional UPS. The UPS 10 has an input stage 12 connected to an AC power supply and an output stage 14 for supplying AC power to an appliance. The input stage 12 has a first switching means 16 connected in series with the output stage 14 and a second switching means 18 connected in parallel with the output stage 14. The output stage 14 has a third switching means 20 connected in series with the input stage 12 and a fourth switching means 22 connected in parallel with the input stage 12. Each of the switching means 16, 18, 20 and 22 is capable of switching current in two directions depending on control signals supplied to the switching means by a controller 24. The controller 24 controls the direction of current through each of the respective switching means in response to detected changes in power conditions.

Abstract: A modular power supply (2) suitable for application as an uninterruptable power supply for use with electrical equipment such as computers. A module (6) of the power supply may include a battery (32), a charging circuit for the battery (34), a power supply circuit coupled to mains electricity and the battery (30, 36, 40), and a control circuit (38) for selectively providing power to the electrical equipment (12) by way of the power supply circuit from either mains electricity (10) or the battery as source. The module is also provided with a coupling which is adapted to connect the module in parallel with at least one other module. A housing may be provided to receive a plurality of modules, which are connected together in parallel by way of plugs and sockets when received in the housing. The plugs and sockets and the control circuit may be adapted to enable "hot-swapping" of the modules from the housing.