Controller for battery charger

Claim 2

A controller for a battery charger, including in combination: a differential amplifier having first and second inputs and an output; a first sample and hold circuit having the battery voltage connected as an input and providing an output as one input to said differential amplifier; a second sample and hold circuit having the output of said first sample and hold circuit as an input and providing an output as the other input to said differential amplifier; an AND gate having first and second inputs and an output, with the AND gate output controlling the battery charger; a first slope detector having the output of said differential amplifier as an input and providing an output when a slope of a first sign is detected; a second slope detector having the output of said differential amplifier as an input and providing an output when a slope of the opposite sign is detected, with said second slope detector output connected as one input to said AND gate; and a latch circuit having the output of said first slope detector connected as input and providing an output as the other input to said AND gate.

Claim 3

A controller for a battery charger, including in combination: means for measuring the voltage of the battery to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; and means for shutting off the charger as a function of said change in slope; said analog to digital converter including a comparator having first and second inputs, a summing circuit having first and second inputs, and an output connected as one input to said comparator, a first digital to analog converter having an output connected as one input to said summing circuit, a second digital to analog converter, a divider circuit having as an input, the output of said second digital to analog converter, with the divider circuit output connected as the other input to said summing circuit, and a sample and hold circuit having the battery voltage connected as an input and having an output connected as the other input to said comparator.

Claim 4

A controller for a battery charger, including in combination: means for measuring the voltage of the battery to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; and means for shutting off the charger as a function of said change in slope; said analog to digital converter including a comparator having first and second inputs, a summing circuit having first and second inputs, and an output connected as one input to said comparator, a first digital to analog converter having an output connected as one input to said summing circuit, a second digital to analog converter, a divider circuit having as an input, the output of said second digital to analog converter, with the divider circuit output connected as the other input to said summing circuit, and a sample and hold circuit having the battery voltage connected as an input and having an output connected as the other input to said comparator.

Claim 5

A controller as defined in claim 2 for use with a battery having an identification resistor, including: means for providing an electrical current of known value in said resistor; means for measuring the voltage developed across said resistor by said current; and means for relating the measured voltage to a predetermined battery identification.

Claim 6

A controller for a battery charger for use with a battery having an identification resistor, wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; means for providing an electrical current of known value in said resistor; means for measuring the voltage developed across said resistor by said current; and means for relating the measured voltage to a predetermined battery identification, said means for relating including: a memory; means for converting the measured voltage to a number; and means for looking up in said memory a battery identification corresponding to said number.

Claim 7

A controller for a battery charger for use with a battery having an identification resistor, wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; means for providing an electrical current of known value in said resistor; means for measuring the voltage developed across said resistor by said current; and means for relating the measured voltage to a predetermined battery identification, said means for relating including: a memory; means for converting the measured voltage to a number; and means for looking up in said memory a battery identification corresponding to said number.

Claim 8

A controller for a battery charger wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; a first battery identification resistor; a current source of known value; first circuit means for connecting said current source across said first resistor to provide a first voltage across said first resistor; a set of parameter tables stored in memory; an index table stored in memory, said index table including an index relating voltage numbers and parameter tables; and means for selecting a parameter table as a function of said first voltage across said first resistor.

Claim 9

A controller for a battery charger wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; a first battery identification resistor; a current source of known value; first circuit means for connecting said current source across said first resistor to provide a first voltage across said first resistor; a set of parameter tables stored in memory; an index table stored in memory, said index table including an index relating voltage numbers and parameter tables; and means for selecting a parameter table as a function of said first voltage across said first resistor.

Claim 10

A controller for a battery charger for use with a battery discharge booster having a current source, wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; a discharge current resistor; and circuit means for connecting said resistor to the current source of the battery discharge booster.

Claim 11

A controller for a battery charger for use with a battery discharge booster having a current source, wherein the battery charger operates in a three step sequence consisting of a charging pulse for a first time period, a discharging pulse for a second time period, and no pulse for a third time period, including in combination: means for measuring the voltage of the battery during said third time period to provide a measured voltage; an analog to digital converter for converting the measured voltage from an analog voltage to a digital voltage; means for computing a time derivative of said digital voltage and determining a change in slope of said time derivative; means for shutting off the charger as a function of said change in slope; a discharge current resistor; and circuit means for connecting said resistor to the current source of the battery discharge booster.