Battery charger and emergency power supply for illumination device

Claim 1

A power supply arrangement for an electrically energized illumination device of the type adapted to receive electrical energy from a primary electrical energy source and supply electrical energy to the illumination device for a normal condition of operation wherein the voltage of the primary electrical energy source is above a predetermined value and for an emergency condition wherein the voltage of the primary electrical energy source is less than a preselected value which is less than the predetermined value, comprising, in combination: voltage control means for receiving electrical energy from the primary electrical energy source and providing a first voltage controlled power input signal, and a second voltage controlled battery charging signal, and said voltage control means connected to the illumination device to transmit said first voltage controlled power output signal thereto; battery means for receiving said second voltage controlled battery charging signal for charging said battery means, and said battery means connected to the illumination device for providing an emergency electrical energy signal thereto for the emergency condition; a first switch means for controlling said first voltage controlled power output signal for transmitting said first voltage controlled power output signal for said first switch means in a transmitting condition, and blocking said first voltage controlled power output signal for said first switch means in a blocking condition; a second switch means for controlling said second voltage controlled battery charging signal to transmit said battery charging signal for said second switch means in a transmitting condition, and blocking said second voltage controlled battery charging signal for said second switch means in a blocking condition; a third switch means for controlling said emergency electrical energy signal for transmitting said emergency electrical energy signal for said third switch means in a transmitting condition, and for blocking said emergency electrical energy signal for said third switch means in a blocking condition; voltage sensing means for sensing the magnitude of the voltage of the primary electrical energy source and battery charge condition and said voltage sensing means having control means portion for operating said first, said second and said third switch means in response to the sensed magnitude of the voltage of the primary electrical energy source and battery charge condition and said control means maintaining said first and said second switch means in said transmitting condition and said third switch means in said blocking condition for the normal condition of operation wherein the sensed magnitude of the voltage of the primary electrical energy source is greater than the preselected value, and said control means for substantially simultaneously switching said first switch means to said blocking condition and switching said third switch means to said transmitting condition for the emergency condition wherein the sensed voltage of the primary electrical energy source is less than the preselected value as the voltage of the primary electrical energy source decreases, and said control means for substantially simultaneously switching said first switch means to said transmitting condition and said third switch means to said blocking condition for said voltage of the primary electrical energy source above the predetermined value as the voltage of the primary electrical energy increases and said control means switching said second switch means between said transmitting condition and said blocking condition in response to said sensed voltage magnitude of said battery charge condition and said sensed voltage magnitude of said primary electrical energy; and voltage limiting means for limiting the maximum voltage value of said second voltage controlled battery charging signal.