High current driver providing battery overload protection

A high current driver for driving a high current load in an electronic device powered by a battery having a terminal voltage which varies in relation to a level of energy consumption from the battery, said high current driver comprising:

• a voltage reference for generating a predetermined reference voltage;
• and
• a drive current controller comprising
• a first switching element, having a first control input responsive to a drive control signal, for selectively switching said first switching element from an active state for supplying current to the high current load, to an inactive state for inhibiting supplying current to the high current load, and
• a second switching element coupled to said first switching element and having a second control input responsive to the predetermined reference voltage, for proportionally reducing the current supplied to the high current load by said first switching element during the active state when the magnitude of the terminal voltage of the battery is substantially equal to a predetermined voltage level.

A communication receiver powered by a battery having a terminal voltage which varies in relation to a level of energy consumption from the battery, comprising:

• a receiver for receiving and detecting coded message signals including an address signal;
• a decoder, responsive to the address signal received, for generating an alert enable signal when the address signal received matches a predetermined address designating the communication receiver;
• a high current alerting device for generating a sensible alert;
• a high current driver, comprising
• a voltage reference generating a predetermined reference voltage, and
• a differential amplifier, having a bias control input, responsive to the alert enable signal, for selectively switching said differential amplifier from an active state for providing a supply of current to said high current alerting device, to an inactive state for inhibiting the supply of current to said high current alerting device,
• said differential amplifier further having a first input, coupled to said voltage reference, and a second input coupled to the battery, said differential amplifier sensing a magnitude of the terminal voltage of the battery during the active state, and in response thereto, generating a drive control signal for proportionally reducing the current supplied to a high current alerting device when the magnitude of the terminal voltage of the battery sensed is substantially equal to a predetermined voltage level;
• and
• a load control element, coupled to said differential amplifier, and responsive to the drive control signal for supplying current to the high current load when the differential amplifier is in the active state and the magnitude of the battery terminal voltage is greater than the predetermined voltage level, and further for proportionally reducing the supply of current supplied to the high current load when the differential amplifier is in the active state and the magnitude of the battery terminal voltage is substantially equal to the predetermined voltage level.

A communication receiver powered by a battery having a terminal voltage which varies in relation to a level of energy consumption from the battery, comprising:

• a receiver for receiving and detecting coded message signals including an address signal;
• a decoder, responsive to the address signal received, for generating an alert enable signal when the address signal received matches a predetermined address designating the communication receiver;
• a high current alerting device for generating a sensible alert;
• and
• a high current driver, comprising
• a voltage reference generating a predetermined reference voltage, and
• a drive current controller comprising
• a first switching element, having a first control input responsive to alert enable signal, for selectively switching said first switching element from an active state for supplying current to said high current alerting device, to an inactive state for inhibiting supplying current to said high current alerting device, and
• a second switching element coupled to said first switching element and having a second control input responsive to the predetermined reference voltage, for proportionally reducing the current supplied to said high current alerting device by said first switching element during the active state when the magnitude of the terminal voltage of the battery is substantially equal to the predetermined voltage level.