Current supply arrangement having a stand-by mode featuring low power consumption

Claim 1

A current supply arrangement for supplying at least one load with electric energy from a source, said current supply arrangement comprising a switching stage for optionally switching-on said at least one load in accordance with a switching signal applied thereto, and a control circuit which, in a switched-off state, cuts off a supply of energy to the switching stage and to said at least one load, and in a switched-on state, controls the supply of energy to at least the switching stage, said control circuit receiving said switching signal for switching between the switched-off state and the switched-on state and comprising a start circuit by which energy required for changing the control circuit from the switched-off state to the switched-on state is supplied from the source to the control circuit, said start circuit being made operative for the supply of energy to the control circuit by the switching signal, said current supply arrangement further comprising a switching signal transmission device for transmitting the switching signal to the switching stage and to the control circuit, said switching signal transmission device being supplied with electrical energy required for its operation from the start circuit, characterized in that said current supply arrangement further comprises switched mode power supply means for receiving energy from said source and for supplying energy to said at least one load and said switching device, said switched mode power supply means having a switching element controlled by the control circuit and an inductive element charged with electric energy from said source by said switching element, said inductive element, in the switched-on state of said control circuit, supplying the energy for the switching stage, and said at least one load, to a supply voltage terminal of the control circuit and, in turn, to the switching signal transmission device, wherein said control circuit assumes the switched-off state when a voltage applied to said supply voltage terminal falls short at least once from a first threshold value and does not exceed a second, higher threshold value, and assumes the switched-on state when the voltage at the supply voltage terminal exceeds the second threshold value at least once and does not fall short of the first threshold value, said control circuit further comprising a capacitive energy storage device coupled to said supply voltage terminal for receiving the energy from said inductive element and coupled to said start circuit for receiving the energy for the switching signal transmission device from the start circuit, said capacitive energy storage device being switched to an active state by the switching signal for the control circuit, and a voltage limiter circuit shunting the capacitive energy storage device, said voltage limiter circuit being operated by the switching signal and limiting the voltage at the capacitive energy storage device for the switched-off state of the control circuit to a value near the second threshold value and lower than the second threshold value.