Electrical Protection Circuitry For A Docking Station Base Of A Hand Held Meter And Method Thereof

• US 20130265682A1
• Filed: 05/10/2013
• Published: 10/10/2013
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Roche Operations Limited (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Ramey, Blaine Edward, Ecoff, Clint Alan, Sauers, Matthew Carlyle, Kurtock, James R., Edwards, Scott Allen, Hartmann, James Joseph
• Granted Patent: US 8,792,221 B2
• Time in Patent Office: Days
• US Class Current: 361/79
• CPC Class Codes: H02H 7/18 for batteries; for accumulators
• CPC Class Codes: H02H 7/20 for electronic equipment for converters H02H7/10; for electric measuring instruments G01R1/36; for dc voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits

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.

Claims

1. A docking station which provides electrical protection between a rechargeable battery provided in a handheld meter and an external power supply which charges the rechargeable battery via the docking station, the docking station being removably connectable to the power supply and comprising:

a base which removably accommodates the handheld meter;

an output terminal provided in the base which supplies power from the power supply to the rechargeable battery upon both the docking station being connected to the power supply and the handheld meter being accommodated in the base which removably couples the rechargeable battery to the output terminal;

a ground terminal provided in the base which grounds the rechargeable battery upon the handheld meter being accommodated in the base which removably couples the rechargeable battery to the ground terminal;

a current monitoring circuit which detects an over-current condition of the rechargeable battery upon both the rechargeable battery being coupled to the output and ground terminals and the docking station being coupled to the power supply, and which outputs an over-current fault detection signal responsive to the over-current condition;

a voltage supervisor circuit which monitors for an out-of-range voltage condition of the power supply when connected to the docking station and at least during and after the rechargeable battery is coupled to both the output and ground terminals, and which outputs a voltage fault detection signal responsive to detection of the out-of-range voltage condition both with and without the rechargeable battery being coupled to both the output and ground terminals;

a switch responsive to the fault detection signals which inhibits the supply of power from the power supply to the output terminal upon detection of either the over-current condition or out-of-range voltage condition; and

a visual indicator responsive to the fault detection signals which provides a visual indication upon detection of either the over-current condition or out-of-range voltage condition.

2. The docking station of claim 1, wherein the output and ground terminals are part of a meter interface connector provided in the base, and the base provides a base drain with an integral cross-shaped slew portion and a connector dam configured to seal the base around at least a portion of the meter interface connector.

3. The docking station of claim 1, wherein the base provides a data connector which couples the meter to a remote system or network upon the meter being accommodated in the base.

4. The docking station of claim 1, wherein the current monitoring circuit outputs the over-current condition upon detection of current flowing through the battery exceeding a predetermined value.

5. The docking station of claim 1, wherein the current monitoring circuit comprises a current sense amplifier provided in a low side current sense amplifier topology.

6. The docking station of claim 1, wherein the current monitoring circuit comprises a current sense amplifier, wherein the current sense amplifier is configured to convert an input current I_in from the ground terminal through a resistor R_sense to an appropriately scaled amplifier output voltage V_amp—

_out.

7. The docking station of claim 1, wherein the current monitoring circuit comprises an amplifier connected to an over-current detector, and the over-current fault detection signal is output of the over-current detector.

8. The docking station of claim 1, wherein the current monitoring circuit comprises an amplifier connected to an over-current detector, the over-current detector comprises a comparator with a threshold voltage V_t—

_hold set with a reference diode, and wherein the reference diode is chosen such that the over-current fault detection signal of the comparator will go low when output of the current sense amplifier corresponds to a predetermined input current limit.

9. The docking station of claim 1, wherein when the over-current condition is detected by the current monitoring circuit, the docking station is configured to latch the switch in a current shutoff mode which cuts power to the output terminal, wherein the docking station is configured to unlatch the switch if power from the power supply is cycled and the over-current condition is not detected.

10. The docking station of claim 1, further comprising a latch circuit, wherein when the over-current condition is detected by the current monitoring circuit, the latch circuit is configured to latch the switch in a current shutoff mode which cuts power to the output terminal, and unlatch the switch if power from the power supply is cycled and the over-current condition is not detected.

11. The docking station of claim 1, further comprising a latch circuit, the latch circuit comprises logic and memory providing an output signal having first and second states, the first state indicating that the over-current condition is not detected, and the second state indicating the over-current condition is detected, wherein when the over-current condition is detected by the current monitoring circuit, the latch circuit is configured to latch the switch in a current shutoff mode which cuts power to the output terminal by the logic being configured to hold the output signal of the memory in the second state until power from the power supply is cycled and the over-current condition is not detected.

12. The docking station of claim 1, wherein the out-of-range voltage condition is defined as a voltage from the power supply being outside a specified range, wherein the voltage supervisor circuit is further configured to restore power to the output terminal when power from the power supply is in the specified range.

13. The docking station of claim 1, wherein the voltage supervisor circuit includes hysteresis to prevent power in the docking station from oscillating due to noise from the power supply.

14. The docking station of claim 1, wherein the voltage supervisor circuit comprises first and second comparators which control the voltage fault detection signal, the voltage fault detection signal having a first state which indicates no out-of-range condition is detected, and a second state which indicates the out-of-range condition is detected, wherein the first comparator is configured to place the voltage fault detection signal in the second state if power from the power supply is below a predetermined value, and the second comparator is configured to place the voltage fault detection signal in the second state if power from the power supply is above a predetermined value.

15. The docking station of claim 1, wherein the switch comprises a transistor.

16. The docking station of claim 1, wherein the switch comprises a transistor having a collector connected to a shutdown circuit of the docking station, wherein the shutdown circuit is configured to enable the collector if the rechargeable battery is coupled to the output terminal and neither the over-current condition nor out-of-range voltage condition is detected by the docking station.

17. The docking station of claim 1, wherein the docking station is configured to switch the switch such that power is provided to the output terminal when voltage of the power supply returns to a predetermined range after an out-of-range voltage condition with no over-current condition being detected by the current monitoring circuit.

18. The docking station of claim 1, wherein the current monitoring circuit comprises a current sense amplifier, a capacitor C₁, and three resistors (R₁, R₂, R_sense), wherein the current sense amplifier is configured to convert an input current I_in from the ground terminal through resistor R_sense to an appropriately scaled amplifier output voltage V_amp—

_out, which is defined by

19. The docking station of claim 1, wherein the visual indicator blinks the visual indication when either the voltage supervisor circuit detects the out-of-range voltage condition or the current monitoring circuit detects the over-current condition, and illuminates the visual indicator continuously when both the rechargeable battery is coupled to the output terminal and neither the over-current nor out-of-range conditions are detected.

20. A docking station which provides electrical protection between a rechargeable battery provided in a handheld meter and an external power supply which charges the rechargeable battery via the docking station, the docking station being removably connectable to the power supply and comprising:

a base which removably accommodates the handheld meter;

an output terminal provided in the base which supplies power from the power supply to the rechargeable battery upon both the docking station being connected to the power supply and the handheld meter being accommodated in the base which removably couples the rechargeable battery to the output terminal;

a ground terminal provided in the base which grounds the rechargeable battery upon the handheld meter being accommodated in the base which removably couples the rechargeable battery to the ground terminal;

a current monitoring circuit which detects an over-current condition of the rechargeable battery upon both the rechargeable battery being coupled to the output and ground terminals and the docking station being coupled to the power supply, and which outputs an over-current fault detection signal responsive to the over-current condition;

a voltage supervisor circuit which before, during, and after coupling the rechargeable battery to both the output and ground terminals continuously monitors for an out-of-range voltage condition of the power supply when the power supply is connected to the docking station, and which outputs a voltage fault detection signal responsive to detection of the out-of-range voltage condition both with and without the rechargeable battery being coupled to both the output and ground terminals;

a switch responsive to the fault detection signals which inhibits the supply of power from the power supply to the output terminal upon detection of either the over-current condition or out-of-range voltage condition, wherein when the over-current condition is detected by the current monitoring circuit, the docking station is configured to latch the switch in a current shutoff mode which cuts power to the output terminal, wherein the docking station is configured to unlatch the switch if power from the power supply is cycled and the over-current condition is not detected, and wherein the docking station is configured to switch the switch such that power is provided to the output terminal when voltage of the power supply returns to a predetermined range after an out-of-range voltage condition with no over-current condition being detected by the current monitoring circuit; and

a visual indicator responsive to the fault detection signals which provides a visual indication upon detection of either the over-current condition or out-of-range voltage condition.

21. A method of providing electrical protection in a docking station which removably accommodates a handheld meter providing a rechargeable battery and which is removably connectable to an external power supply, the method comprising:

providing an output terminal of the docking station which supplies power from the power supply to the rechargeable battery upon both the docking station being connected to the power supply and the handheld meter being accommodated in the base which removably couples the rechargeable battery to the output terminal;

providing a ground terminal of the docking station which grounds the rechargeable battery upon the handheld meter being accommodated in the base which removably couples the rechargeable battery to the ground terminal;

monitoring continuously voltage of the power supply when connected to the docking station and at least during and after the rechargeable battery is coupled to both the output and ground terminals via a voltage supervisor circuit of the docking station, wherein the voltage supervisor circuit outputs a voltage fault detection signal responsive to detection of an out-of-range voltage condition both with and without the rechargeable battery being coupled to both the output and ground terminals;

monitoring current of the power supply when the rechargeable battery is coupled to the output and ground terminals via a current monitoring circuit of the docking station, wherein the current monitoring circuit outputs an over-current fault detection signal responsive to detection of an over-current condition;

providing a voltage fault detection signal responsive to the out-of-range voltage condition being detected by the voltage supervisor circuit of the docking station;

inhibiting power from the power supply to the output terminal when either the over-current condition or out-of-range voltage condition is detected via a switch of the docking station that is responsive to the fault detection signals; and

providing a visual indication upon detection of either the over-current condition or out-of-range voltage condition via a visual indicator responsive to the fault detection signals.