Abstract:
A portable lighting apparatus comprising a re-chargable battery and a plurality of LED&#39;s (light emitting diode) located on a PCB are housed in separate enclosures. The battery is managed by a first microprocessor in the battery enclosure and operation of the LED(s) is managed by a second microprocessor in the lamp enclosure. The two microprocessors are connected to respective data transmitters which generate signals to pass information and/or commands between the two microprocessors. The electrical systems of the two enclosures are interconnected by a bi-direction data link formed by a twin core cable.

Description:
FIELD 
       [0001]    This invention relates to a battery monitoring device for monitoring the use and condition of a battery of a portable LED lighting device. 
       BACKGROUND OF THE INVENTION 
       [0002]    Portable illumination devices of the type used for the illumination of buildings or work sites are well known and it is typical for the light source of the lamp to be separately housed from a battery container with the lamp being connected to the battery or batteries through a multi-core cable sometimes with the use of pin and socket connectors. In some cases the light source may comprise one or more LEDs and the battery may be connected to the light source through a electronic controller as is shown in EP1072493. In more sophisticated lighting equipment as is shown in CN201215298, the portable light may be provided with a electrical energy management system in which the battery is controlled through an electronic control circuit. Where LEDs are used as the light source they may be operated by driver chips located on a circuit board in the lamp housing. 
         [0003]    The present invention provides an improved portable lamp in which the battery and lamp are housed in separate enclosures. 
       STATEMENT OF INVENTION 
       [0004]    According to the present Invention, there is provided a portable lighting apparatus in which a re-chargable battery and at least one LED (light emitting diode) are housed in separate enclosures, the battery being managed by a first microprocessor in a battery enclosure and the operation of the LED(s) being managed by a second microprocessor in a lamp enclosure, the two microprocessors being in communication to pass information and/or commands between the two microprocessors. 
         [0005]    The apparatus may comprise a plurality of LED&#39;s which are located on a PCB. 
         [0006]    Preferably the battery is a re-chargable battery. 
         [0007]    Preferably, the first microprocessor forms part a battery module electrical system and the second microprocessor forms part of a lamp module electrical system, the two modules being interconnected by a bi-directional data link formed by a twin core cable. 
         [0008]    The bi-directional data link may comprise a first switching device in the battery module electrical system and a second switching device in the lamp module electrical system for selecting a low impedance mode to transfer power to the lamp module electrical circuit and a high impedance mode for sending data between the two modules. Preferably, the switching devices comprise respective field effect transitors, more preferably N-channel metal oxide field effect transistors which may be wired into the negative channel in the electrical system. 
         [0009]    In the high impedance mode a limited amount of DC power, preferably &lt;0.1 Watts can be transferred from the battery to the lamp module electrical system to power the second microcontroller. 
         [0010]    For a portable lighting apparatus according to the first aspect of the present invention, there is provided a method of controlling the transfer of power and data between the first and second microprocessors wherein the battery is connected to a battery module electrical system and the LED is connected to a lamp module electrical system and a bi-directional data link is provided by switching the battery module electrical system and the lamp module electrical system to select a low impedance mode to transfer power to the lamp module electrical circuit and a high impedance mode for sending data between the two modules. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0011]    The Invention will be described by way of Example and with reference to the accompanying drawings in which: 
           [0012]      FIG. 1  is an isometric view of a portable lamp apparatus also according to the present invention. 
           [0013]      FIG. 2  is a schematic sectional drawing through the lamp module, 
           [0014]      FIG. 3  is a block diagram of the electrical system for the lighting apparatus electrical system, and 
           [0015]      FIG. 4  is a Flow diagram showing the operational sequence 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    With reference to  FIG. 1  and  FIG. 2 , there is shown a portable lighting apparatus  51  having a lamp module  10  and a battery module  12 . The lamp module  10  has a separate lamp enclosure  11  and the battery module includes a battery enclosure  12  A. The lamp module  10  is mounted at one end of the battery module  12  and is attached to the battery module  12  by a pin  55  passing through lugs  54  on the battery enclosure  12 A. This allows the lamp module  10  to be adjusted to different angles of orientation relative to the battery module  12 . 
         [0017]    The lamp module  10  comprises a moulded plastics enclosure  11  having a front cover  17  with a transparent central portion  22 . The housing  11  has a PCB (Printed Circuit board)  13  mounted therein with twin core cable  14  connecting the PCB to a twin core connector  45  for connection to a battery module electrical system in the battery enclosure  12 A. The PCB  13  includes an array of high output LED&#39;s  15  arranged in a desired array for example columns and rows. The electrical connector  45  between the battery module  12  and the lamp module  10  comprises two pins  43 , 44  and corresponding sockets (see below). 
         [0018]    Now with reference to  FIG. 3 , there is shown a schematic diagram of a electrical system for the lighting apparatus and which comprises an electrical management system  30  for battery module  12  and a lamp module electrical system  50  which controls operation of the LEDs  15 . In the electrical management system  30  for the battery module, a re-chargable battery  31  has its positive terminal connected to the positive pin  43  of the connector  45  to the lamp module electrical system  50  and its negative terminal connected to a negative pin  44  in the connector  45 . A resistor  42 , in the order of 1K ohm, is in series with the return to negative terminal and is connected in series with a switching device  41  which can allow the resistor  42  to be by-passed. The operation of the switching device  41  is controlled by a microprocessor  34 . 
         [0019]    The DC power from the battery is controlled by a voltage regulator  32  which provides a regulated power supply to the microprocessor  34 . The microprocessor  34  is pre-programmed to manage the battery and monitors battery condition (charge state), controls re-charge, operates low charge state alarms (for example a suitably coloured LED), confirms correct battery type, and will disconnect the load on the battery to prevent damage due to excess discharge. To that end the microprocessor  34  is connected to a plurality of different sensors and devices which are represented by the crystal clock  33  which provide for timed intervals, preferably in the order of 1.0 second. 
         [0020]    The microprocessor  34  is also connected to a data transmitter  36  which provides current pulses for transmitting data from the processor  34  to the lamp module electrical system  50 . A low pass filter  35  is provided in the negative return to the microprocessor  34  to remove high frequency noise from data received from the lamp module as will be described later. 
         [0021]    Such a system will be formed on a PCB housed in the battery enclosure  12 A. 
         [0022]    With reference now to the electrical management system  50  for the lamp module  10 , this will be formed on the PCB  13 . The positive socket  43  of connector  45  is connected to the LED array  15  through a low pass filter  52 . The LED array is connected to the negative socket  44  of connector  45  through the low pass filter  52 , via a current regulator  63  and in series with a switching device  56 . The current regulator  63  controls and regulates the current to, and brightness of, the LEDs  15 . The low-pass filter  52  attenuates noise from the current regulator  63 . 
         [0023]    The positive socket  43  is also connected to a microprocessor  60  through a voltage regulator  59 . The microprocessor  60  is pre-programmed to control the LED illumination in line with battery charge and stores information in relation the operation of the LEDs and communicates with the battery microprocessor  34 . The micro-processor  60  may also control operation other components associated with the illumination, for example, a diffuser. 
         [0024]    The microprocessor  60  is connected to the switching device  56  and is also connected to the current regulator  63  and to a data transmitter  55  which provides current pulses for data transmission to the microprocessor  34  in the battery module. 
         [0025]    An energy storage device  57  is provided in the electrical system to power the LED&#39;s  15  and/or microprocessor  60  when the battery system is in high impedance mode. The storage device  57  is charged by a diode  58  connected across the switching device  56 . The diode  58  provides a circuit for the current from the resistor  42  to reach the energy storage device  57 . The storage device  57  is charged to a peak voltage based on the forward voltage from the battery  31  minus the forward voltage drop of the diode  56 . 
         [0026]    The two switches  41  and  56  may be selected from suitable power switching transistors such as field effect transistors and Bipolar junction transistors and even relays. The preferred option is for the use of N-Channel metal oxide field effect transistors with the negative connection in series with the negative from the lamp. 
         [0027]    The microprocessor  60  is also connected to a wireless 2.4 GHz transceiver  61  which can communicate with a remote control (not shown) which is based on the published IEEE 802.15.4 signaling protocol. The transceiver  61  is required to be available while the lamp module is in the OFF state when power consumption must be kept as low as possible. 
         [0028]    The DC power to the transceiver  61  is cycled between the active (30 mA) and off (3 uA) states, once per second, so that the average power consumption when the lamp is OFF is within the acceptable off-state current load on the battery. 
         [0029]    The two interconnected battery and lamp electrical systems  30  &amp;  50  provide a bidirectional data link between the battery and the lamp modules, so that the lamp module can verify that a battery of the correct type for the lamp is used, as well as manage operation of the battery and pass date between the battery and lamp microprocessors  34  &amp;  60 . 
         [0030]    The invention consists of switching the two interconnected systems using a twin wire connection  14  with the switches  41  &amp;  56  to select either a low impedance power transfer mode, or a high impedance signalling mode, and uses a protocol to switch both ends between the two modes at the same time. 
         [0031]    When the interconnected systems are in the Low Impedance Power Transfer mode, both switch  41  in the battery module and switch  56  in the lamp module are ON. In this mode, the energy storage device  57  in the lamp module is charged directly by the battery. In the low impedance power transfer mode, the circuit is used to convey a significant electrical power of the order of thirty Watts, to the LED,s and no signalling is possible. 
         [0032]    In the High impedance signalling mode, the interconnected systems convey bidirectional signalling pulses allowing communication between the microprocessors  60  &amp;  34  in the lamp module and the battery module respectively. When in the High Impedance Data Transfer mode, both switch  41  in the battery module and switch  56  in the lamp module are OFF. Only a limited amount of DC power, of the order of 0.1 Watts, can be transferred from the battery module to the lamp module, to provide power to the microcontroller  60 , and the remote control receiver  61 , which is located in the lamp module. 
         [0033]    The energy storage device  57  is charged through resistor  42  in the battery module and the reverse body Diode  58 . In both the High Impedance data Transfer mode, or the Low Impedance Power Transfer Mode, DC power from the battery is supplied to the energy storage device  57 , which supplies power to the microprocessor  60  via the regulator  59 . 
         [0034]    Now with reference to  FIG. 4  on start-up (when the user presses the ON button) in Step  80 , typically on a remote control, the control transmits a series of command packets to the wireless transceiver  61  repeating every 4 mS for a timed maximum interval of 10 seconds. When the transceiver  61  in the LED lamp next switches ON, the receiver  61  detects the remote command and sends an acknowledge packet, which causes the remote control to stop sending. The circuit is by default in the High Impedance mode. In steps  81 - 84 , the lamp module microprocessor  60  sends a series of signal pulses to the microprocessor  34  in the battery module which then replies with a series of pulses. Providing that this signalling is completed without error, as determined in steps  85  &amp;  86 , both switches  41  and  56  are switched ON and to the low impedance power delivery mode, step  87 . 
         [0035]    Further, in this arrangement there is a protocol in steps  88 - 90  for determining when the lamp has been switched off, and the battery should switch back to the high impedance state. In the present invention this is done in the Battery unit by testing the current draw step  89  after a timed interval Step  88 , once per second. If the lighting apparatus is off, the system is switched back to high impedance mode in step  90 . 
         [0036]    Further to this power conservation method, is a method for indicating to the user the status of the battery in the lamp unit. One of the bytes in the acknowledge packet is varied according to the voltage of the battery in the battery module plugged into the lamp LED unit, using an A-D converter. 
         [0037]    Then the LED indicator in the remote control signals the user by showing Green, Yellow, Red, or Flashing Red status, the need for charging the battery in the lamp unit, without requiring any further signalling.