Electrical protection circuitry for a docking station base of a hand held meter and method thereof

Abstract

An electrical protection circuitry for a docking station base of a hand held meter and method thereof are disclosed. In the event of a short circuit at a meter interface connector, the protection circuitry removes power at the meter interface connector. Similarly, in the event of an applied voltage outside a specified operating range of the base, the protection circuitry removes power to the meter interface connector. These conditions of the electrical system of the base are monitored regardless whether the meter or the meter's battery is electrically connected to the base. The protection circuitry also provides a visual indication in the event of either the over current and under/over voltage conditions. Additionally, the base is designed to prevent liquid from pooling inside a pocket used to cradle and hold the meter in the base through the use of a drain located at the lowest point in the pocket.

1 . An apparatus providing electrical protection between a rechargeable battery and a power supply, said apparatus comprising: 
 an output terminal for supplying power from the power supply to the rechargeable battery;    a ground terminal for grounding the chargeable battery;    a current monitoring circuit adapted to detect an over-current condition of the rechargeable battery when both the rechargeable battery is coupled to said output and ground terminals and said apparatus is coupled to the power supply, and to output an over-current fault detection signal responsive to said over-current condition;    a voltage supervisor circuit adapted to detect an out-of-range voltage condition of the power supply when the apparatus is coupled thereto and regardless if the rechargeable battery is coupled to said output and ground terminals, and to output a voltage fault detection signal responsive to said out-of-range voltage condition; and    a switch responsive to said fault detection signals, said switch is adapted to inhibit supplying power from the power supply to said output terminal when either said over-current condition or out-of-range voltage condition is detected.    
     
     
         2 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery.  
     
     
         3 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held blood glucose meter providing the rechargeable battery.  
     
     
         4 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery, said base comprising a base drain.  
     
     
         5 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery, said base comprising a base drain with an integral cross-shaped slew portion.  
     
     
         6 . The apparatus of  claim 1  wherein said output and ground terminals are part of a meter interface connector, and said meter interface connector is part of a docking station base for a hand held meter providing the rechargeable battery.  
     
     
         7 . The apparatus of  claim 1  wherein said output and ground terminals are part of a meter interface connector, and said meter interface connector is part of a docking station base for a hand held meter providing the rechargeable battery, said base comprising a base drain and connector dam adapted to seal said base around at least a portion of said meter interface connector.  
     
     
         8 . The apparatus of  claim 1  wherein the power supply is coupled to said apparatus via a power cord.  
     
     
         9 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery, and said apparatus further comprises a data connector adapted to couple said meter to a remote system when said meter is connected to said base.  
     
     
         10 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery, and said apparatus further comprises a meter interface connector providing said output and ground terminals, and a data connector adapted to couple said meter to a remote system when said meter is connected to said base, said data connector being coupled to said meter interface connector.  
     
     
         11 . The apparatus of  claim 1  wherein said current monitoring circuit comprises a current sense amplifier provided in a low side current sense amplifier topology.  
     
     
         12 . The apparatus of  claim 1  wherein said current monitoring circuit comprises a current sense amplifier, wherein said current sense amplifier is adapted to convert an input current I in  from said ground terminal through a resistor R sense  to an appropriately scaled amplifier output voltage V amp     —     out .  
     
     
         13 . The apparatus of  claim 1  wherein said current monitoring circuit comprises an amplifier connected to an over-current detector.  
     
     
         14 . The apparatus of  claim 1  wherein said current monitoring circuit comprises an amplifier connected to an over-current detector, and said over-current fault detection signal is output of said over-current detector.  
     
     
         15 . The apparatus of  claim 1  wherein said current monitoring circuit comprises an amplifier connected to an over-current detector, said over-current detector comprises a comparator with a threshold voltage V  t     —     hold .  
     
     
         16 . The apparatus of  claim 1  wherein said current monitoring circuit comprises a current sense amplifier connected to an over-current detector, said over-current fault detection signal is output of said over-current detector, wherein said over-current detector comprises a comparator with a threshold voltage V  t     —     hold  set with a reference diode, and wherein said reference diode is chosen such that said over-current fault detection signal of said comparator will go low when output of said current sense amplifier corresponds to a predetermined input current limit.  
     
     
         17 . The apparatus of  claim 1  wherein said over-current condition is defined by said current monitoring circuit detecting current flowing through said meter exceeding a predetermined value.  
     
     
         18 . The apparatus of  claim 1  wherein when said over-current condition is detected by said current monitoring circuit, said apparatus is adapted to latch said switch in a current shutoff mode which cuts power to said output terminal, wherein said apparatus is adapted to unlatch said switch if power from the power supply is cycled and said over-current condition is not detected.  
     
     
         19 . The apparatus of  claim 1  further comprising a latch circuit, wherein when said over-current condition is detected by said current monitoring circuit, said latch circuit is adapted to latch said switch in a current shutoff mode which cuts power to said output terminal, and unlatch said switch if power from the power supply is cycled and said over-current condition is not detected.  
     
     
         20 . The apparatus of  claim 1  further comprising a latch circuit, said latch circuit comprises logic and memory providing an output signal having first and second states, said first state indicating that said over-current condition is not detected, and said second state indicating said over-condition is detected, wherein when said over-current condition is detected by said current monitoring circuit, said latch circuit is adapted to latch said switch in a current shutoff mode which cuts power to said output terminal by said logic being adapted to hold said output signal of said memory in said second state until power from the power supply is cycled and said over-current condition is not detected.  
     
     
         21 . The apparatus of  claim 1  further comprising a visual indicator, wherein if said voltage supervisor circuit detects said out-of-range voltage condition regardless if the rechargeable battery is connected to said output terminal, said apparatus is adapted to blink said visual indicator, wherein if the rechargeable battery is coupled to said output terminal and said current monitoring circuit detects said over-current condition, said apparatus is adapted to blink said visual indicator, and wherein if said rechargeable battery is coupled to said output terminal and neither said over-current nor out-of-range conditions are detected by the apparatus, said apparatus is adapted to illuminate said visual indicator continuously.  
     
     
         22 . The apparatus of  claim 1  wherein said out-of-range voltage condition is defined as a voltage from the power supply being outside a specified range, wherein said voltage supervisor circuit is further adapted to restore power to said output terminal when power from the power supply is in said specified range.  
     
     
         23 . The apparatus of  claim 1  wherein said voltage supervisor circuit includes hysteresis to prevent power in said apparatus from oscillating due to noise from the power supply.  
     
     
         24 . The apparatus of  claim 1  wherein said voltage supervisor circuit comprises first and second comparators which control said voltage fault detection signal, said voltage fault detection signal having a first state which indicates no out-of-range condition is detected, and a second state which indicates said out-of-range condition is detected, wherein said first comparator is adapted to place said voltage fault detection signal in said second state if power from said power supply is below a predetermined value, and said second comparator is adapted to place said voltage fault detection signal in said second state if power from the power supply is above a predetermined value.  
     
     
         25 . The apparatus of  claim 1  wherein said switch comprises a transistor.  
     
     
         26 . The apparatus of  claim 1  wherein said switch comprises a transistor having a collector connected to a shutdown circuit of said apparatus, wherein said shutdown circuit is adapted to enable said collector if the rechargeable battery is coupled to said output terminal and neither said over-current condition nor out-of-range voltage condition is detected by the apparatus.  
     
     
         27 . The apparatus of  claim 1  wherein said apparatus is adapted to switch said switch such that power is provided to said output terminal when voltage of said power supply returns to a predetermined range after an out-of-range voltage condition with no over-current condition being detected by said current monitoring circuit.  
     
     
         28 . The apparatus of  claim 1  wherein said apparatus is a docking station base for a hand held meter providing the rechargeable battery, and said apparatus further comprises a serial data connector adapted to couple said meter to a remote system when said meter is connected to said base.  
     
     
         29 . An apparatus providing a data connection to a remote system, a power connection, and electrical protection for a hand held meter having a rechargeable battery, said apparatus comprising: 
 a power supply;    a data connector;    a meter interface connector having an output terminal and a ground terminal, and being connected to said data connector, said meter interface connector couples the rechargeable battery to the power supply;    a current monitoring circuit coupled to the ground terminal, said current monitoring circuit adapted to detect an over-current condition of the rechargeable battery when said battery is coupled to said meter interface connector, and output an over-current fault detection signal in response to detecting said over-current condition;    a voltage supervisor circuit coupled to said power supply, said voltage supervisor circuit is adapted to detect an out-of-range voltage condition of said power supply regardless if the rechargeable battery is coupled to said meter interface connector, and output a voltage fault detection signal in response to detecting said out-of-range voltage condition;    a switch coupled between said output terminal and said power supply, said switch being adapted to inhibit supplying power to said output terminal in response to being switched by either of said fault detection signals; and    a visual indicator adapted to provide a visual indication in response to being activated by either of said fault detection signals.    
     
     
         30 . A blood glucose monitoring system for use with a remote computer system, comprising: 
 a hand held blood glucose meter having a rechargeable battery;    a power supply; and    a docking station base having a base drain and an electrical system, said electrical system comprising: 
 a power connector coupled to said power supply,  
 a data connector adapted to connect to the remote computer system,  
 a meter interface connector having an output terminal and a ground terminal, and being connected to said data connector and said power connector, said meter interface connector couples the rechargeable battery to the power supply, and said meter to the remote computer,  
 a current monitoring circuit coupled to the ground terminal, said current monitoring circuit adapted to detect an over-current condition of the rechargeable battery when said meter is coupled to said meter interface connector, and output an over-current fault detection signal in response to detecting said over-current condition,  
 a voltage supervisor circuit coupled to said power supply, said voltage supervisor circuit is adapted to detect an out-of-range voltage condition of said power supply regardless if the meter is coupled to said meter interface connector, and output a voltage fault detection signal in response to detecting said out-of-range voltage condition,  
 a switch coupled between said output terminal and said power supply, said switch being adapted to inhibit supplying power to said output terminal in response to being switched by either of said fault detection signals, and  
 a visual indicator adapted to provide a visual indication in response to being activated by either of said fault detection signals.  
   
     
     
         31 . A method of providing electrical protection between a rechargeable battery and a power supply, said method comprising: 
 providing an output terminal for supplying power from the power supply to the rechargeable battery;    providing a ground terminal for grounding the rechargeable battery;    monitoring current when the rechargeable battery is coupled to said output and ground terminals via a current monitoring circuit adapted to detect an over-current condition;    monitoring voltage of the power supply regardless if the rechargeable battery is coupled to said output and ground terminals via a voltage supervisor circuit adapted to detect an out-of-range voltage condition of the power supply;    providing an over-current fault detection signal responsive to an over-current condition being detected by said current monitoring circuit;    providing a voltage fault detection signal responsive to said out-of-range voltage condition being detected by said voltage supervisor circuit; and    providing a switch responsive to said fault detection signals, said switch inhibiting power from the power supply coupling with said output terminal when either said over-current condition or out-of-range voltage condition is detected.    
     
     
         32 . The method of  claim 31  wherein said method is performed by a docking station base for a hand held meter providing the rechargeable battery.  
     
     
         33 . The method of  claim 31  wherein said method is performed by a docking station base for a hand held blood glucose meter providing the rechargeable battery.  
     
     
         34 . The method of  claim 31  wherein said method is performed by a docking station base for a hand held blood glucose meter providing the rechargeable battery, and said method further comprises providing means to drain liquid from said base.  
     
     
         35 . The method of  claim 31  wherein said method is performed by a docking station base for a hand held blood glucose meter providing the rechargeable battery, and said method further comprises providing means to prevent liquid ingress into said base.  
     
     
         36 . The method of  claim 31  wherein said output and ground terminals are provided as part of a meter interface connector, and said meter interface connector is provided as part of a docking station base for a hand held meter providing the rechargeable battery.  
     
     
         37 . The method of  claim 31  wherein said current monitoring circuit is provided as a current sense amplifier provided in a low side current sense amplifier topology.  
     
     
         38 . The method of  claim 31  wherein said current monitoring circuit is performed by a current sense amplifier, a capacitor C 1 , and three resistors (R 1 , R 2 , R sense ), wherein said current sense is adapted to convert an input current I in  from said ground terminal through resistor R sense  to an appropriately scaled amplifier output voltage V amp     —     out , which is defined by  
       
         
           
             
               
                 
                   V 
                   amp_out 
                 
                 = 
                 
                   
                     I 
                     
                       i 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       n 
                     
                   
                   ⁢ 
                   
                     
                       R 
                       sense 
                     
                     ⁡ 
                     
                       ( 
                       
                         
                           
                             R 
                             2 
                           
                           
                             R 
                             1 
                           
                         
                         + 
                         1 
                       
                       ) 
                     
                   
                 
               
               , 
             
           
         
       
       and wherein resistors R 1  and R 2  set gain of said amplifier, and resistor R 2  and capacitor C 1  limit bandwidth.  
     
     
         39 . The method of  claim 31  wherein said current monitoring circuit is performed by connecting an amplifier to an over-current detector.  
     
     
         40 . The method of  claim 31  wherein said current monitoring circuit is performed by connecting an amplifier to an over-current detector, and said over-current fault detection signal is output of said over-current detector.  
     
     
         41 . The method of  claim 31  wherein said current monitoring circuit is performed by connecting an amplifier to an over-current detector, said over-current detector comprising a comparator with a threshold voltage V  t     —     hold  set with a reference diode.  
     
     
         42 . The method of  claim 31  wherein said current monitoring circuit is performed by connecting a current sense amplifier to an over-current detector, said over-current fault detection signal is output of said over-current detector, wherein said over-current detector comprises a comparator with a threshold voltage V  t     —     hold  set with a reference diode, and wherein said reference diode is chosen such that said over-current fault detection signal of said comparator will go low when output of said current sense amplifier corresponds to a predetermined input current limit.  
     
     
         43 . The method of  claim 31  wherein said over-current condition is defined by said current monitoring circuit detecting current flowing through said meter exceeding a predetermined value.  
     
     
         44 . The method of  claim 31  further comprising latching said switch in a current shutoff mode which cuts power to said output terminal when said over-current condition is detected by said current monitoring circuit, and unlatching said switch if power from the power supply is cycled and said over-current condition is not detected.  
     
     
         45 . The method of  claim 31  further comprising providing a visual indicator to indicate whether either one of the conditions has been detected.  
     
     
         46 . The method of  claim 31  further comprising providing a visual indicator, wherein if said voltage supervisor circuit detects said out-of-range voltage condition regardless if the rechargeable battery is connected to said output terminal, said apparatus is adapted to blink said visual indicator, wherein if the rechargeable battery is coupled to said output terminal and said current monitoring circuit detects said over-current condition, said apparatus is adapted to blink said visual indicator, and wherein if said battery is coupled to said output terminal and neither said over-current nor out-of-range conditions are detected by the apparatus, said apparatus is adapted to illuminate said visual indicator continuously.  
     
     
         47 . The method of  claim 31  wherein said out-of-range voltage condition is defined as a voltage from the power supply being outside a specified range, and said method further comprises restoring power to said output terminal when power from the power supply is in said specified range.  
     
     
         48 . The method of  claim 31  further comprising preventing power from oscillating due to noise from the power supply.  
     
     
         49 . The method of  claim 31  wherein said voltage supervisor circuit is performed by controlling said voltage fault detection signal using first and second comparators, said voltage fault detection signal having a first state which indicates no out-of-range condition is detected, and a second state which indicates said out-of-range condition is detected, wherein said first comparator is adapted to place said voltage fault detection signal in said second state if power from said power supply is below a predetermined value, and said second comparator is adapted to place said voltage fault detection signal in said second state if power from the power supply is above a predetermined value.  
     
     
         50 . The method of  claim 31  further comprising switching said switch to return power to said output terminal when voltage of said power supply returns to a predetermined range after an out-of-range voltage condition with no over-current condition being detected by said current monitoring circuit.