Fail-safe load power management system
First Claim
1. In apparatus having at least one load power circuit controlling the level of electrical power applied to at least one load from a power source, each load power circuit of the type setting the level of power applied to the load as a predetermined function of the voltage applied to a control terminal of the load power circuit and removing power from the load when the voltage at the load power circuit'"'"'s control terminal is within a first voltage range, an interface circuit having an output terminal for connection to the load power circuit'"'"'s control terminal and an input terminal for receiving a variable energy management control voltage, said interface circuit including:
- (a) a voltage translator means having an input terminal comprising the interface circuit'"'"'s input terminal and receiving the energy management control voltage thereat and a disable input at which is received a disable signal, and having an output terminal comprising the interface circuit'"'"'s output terminal, for supplying when the disable signal is absent, a voltage at the interface circuit'"'"'s output terminal which is a predetermined function of the energy management control voltage and which includes at least a part of the first voltage range, and for supplying at the interface circuit'"'"'s output terminal when the disable signal is present at the disable input, a predetermined safety voltage which is outside of the first voltage range; and
(b) a threshold detector receiving the energy management control voltage and providing the disable signal to the disable input of the voltage translator means responsive to the energy management control voltage falling within a second voltage range.
1 Assignment
0 Petitions
Accused Products
Abstract
An electric power consuming system such as the lighting in a building has local control units for adjusting the power consumed by a preselected load or loads associated with each local control unit. The control units generate a selectable control voltage which has a first range specifying to the loads that no power should be consumed by the loads with voltage outside the first range specifying by its level the amount of power which the loads should draw. The system also includes energy management apparatus whose output is connected across the output of the control units and which can limit the power individual control units can specify to their loads. The invention comprises an interface circuit which connects the energy management apparatus to the control units and translates control voltages from the energy management apparatus falling within a second voltage range within the first range of the selectable control voltage, to a voltage falling outside the first voltage range. The energy management apparatus is of the type which during common failure modes, provides a control voltage within the second range. In this way, safety is not compromised by reason of malfunctioning energy management apparatus turning off lights in occupied areas.
27 Citations
20 Claims
-
1. In apparatus having at least one load power circuit controlling the level of electrical power applied to at least one load from a power source, each load power circuit of the type setting the level of power applied to the load as a predetermined function of the voltage applied to a control terminal of the load power circuit and removing power from the load when the voltage at the load power circuit'"'"'s control terminal is within a first voltage range, an interface circuit having an output terminal for connection to the load power circuit'"'"'s control terminal and an input terminal for receiving a variable energy management control voltage, said interface circuit including:
-
(a) a voltage translator means having an input terminal comprising the interface circuit'"'"'s input terminal and receiving the energy management control voltage thereat and a disable input at which is received a disable signal, and having an output terminal comprising the interface circuit'"'"'s output terminal, for supplying when the disable signal is absent, a voltage at the interface circuit'"'"'s output terminal which is a predetermined function of the energy management control voltage and which includes at least a part of the first voltage range, and for supplying at the interface circuit'"'"'s output terminal when the disable signal is present at the disable input, a predetermined safety voltage which is outside of the first voltage range; and (b) a threshold detector receiving the energy management control voltage and providing the disable signal to the disable input of the voltage translator means responsive to the energy management control voltage falling within a second voltage range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A voltage level shifting circuit having an input terminal to which may be applied a input voltage varying from within to outside of a predetermined voltage range, and an output terminal at which the circuit supplies an output voltage, comprising
(a) a voltage translator means having input and output terminals comprising the circuit'"'"'s input and output terminals respectively, and having a disable terminal at which is received a disable signal, for supplying when the disable signal is absent, a voltage at the output terminal which is a predetermined function of the input voltage, and for supplying at the output terminal when the disable signal is present at the disable terminal, a voltage outside of the voltage range; - and
(b) a threshold detector receiving the input voltage and providing the disable signal to the disable terminal of the voltage translator means responsive to the input voltage falling within the voltage range. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- and
Specification