Reverse battery protection for battery-powered devices

A battery-powered biosensor meter comprising:

• a microcontroller configured to determine a property of an analyte in a fluid;
• a memory coupled to the microcontroller to store measurement results;
• a battery holder configured to receive a plurality of batteries;
• a reverse battery protection circuit coupled to the battery holder, the microcontroller, and the memory;
• and
• a housing configured to house the microcontroller, the memory, the battery holder, and the reverse battery protection circuit,
• wherein the reverse battery protection circuit includes:
• a first load terminal;
• a second load terminal;
• a first P-channel MOSFET having a drain, a gate, and a source coupled to the first load terminal;
• a first N-channel MOSFET having a drain, a gate, and a source coupled to the second load terminal;
• a first positive battery terminal connector coupled to the drain of the first P-channel MOSFET and to the gate of the first N-channel MOSFET, the first positive battery terminal connector configured to electrically connect to a first battery terminal;
• and
• a first negative battery terminal connector coupled to the drain of the first N-channel MOSFET and to the gate of the first P-channel MOSFET, the first negative battery terminal connector configured to electrically connect to a second battery terminal.

A reverse battery protection circuit comprising:

• a first P-channel MOSFET having a gate, a drain, and a source;
• a second P-channel MOSFET having a gate, a drain coupled to the gate of the first P-channel MOSFET, and a source coupled to the source of the first P-channel MOSFET;
• a first N-channel MOSFET having a gate coupled to the gate of the second P-channel MOSFET, a drain coupled to the drain of the second P-channel MOSFET and to the gate of the first P-channel MOSFET, and a source;
• a first load terminal coupled to the drain of the first P-channel MOSFET;
• a first positive battery terminal connector coupled to the source of the first P-channel MOSFET and to the source of the second P-channel MOSFET, the first positive battery terminal connector configured to electrically connect to a first battery terminal;
• a second positive battery terminal connector coupled to the gate of the first N-channel MOSFET and to the gate of the second P-channel MOSFET, the second positive battery terminal connector configured to electrically connect to a second battery terminal;
• a first negative battery terminal connector configured to electrically connect to a third battery terminal;
• a second negative battery terminal connector configured to electrically connect to a fourth battery terminal;
• and
• a second load terminal;
• wherein:
• the first negative battery terminal, the second negative battery terminal, the second load terminal, and the source of the first N-channel MOSFET are coupled to each other.

A method of protecting a load from a reverse battery connection, the method comprising:

• coupling a source of a first P-channel MOSFET to a first load terminal;
• coupling a source of a first N-channel MOSFET to a second load terminal;
• coupling a first positive battery terminal connector to a drain of the first P-channel MOSFET and to a gate of the first N-channel MOSFET, the first positive battery terminal configured to electrically connect to a first battery terminal;
• and
• coupling a first negative battery terminal connector to a drain of the first N-channel MOSFET and to a gate of the first P-channel MOSFET, the first negative battery terminal configured to electrically connect to a second battery terminal.