Battery charger with monitor and protection circuits

A charging apparatus for charging a battery, the charging apparatus comprising:

• a direct current power source;
• an inverter for converting a direct current from the power source into an alternating current;
• a transformer including a first coil and a second coil, wherein the second coil produces an alternating voltage when the alternating current from the inverter is applied to the first coil, and wherein the second coil has a pair of terminals;
• a booster circuit connected between the terminals of the second coil for increasing the alternating voltage produced in the second coil;
• a rectifier circuit for rectifying the alternating voltage increased in the booster circuit to a direct current voltage, the rectifier circuit applying the direct current voltage to the battery for charging;
• a monitor for monitoring the direct current voltage from the rectifier circuit, wherein the monitor outputs a drive signal when the direct current voltage is equal to or higher than a predetermined permissible value;
• a short circuit for short-circuiting the terminals of the second coil in response to the drive signal from the monitor;
• a first circuit including the direct current power source, the inverter, and the first coil;
• and
• a second circuit including the second coil, the booster circuit, the rectifier circuit, the monitor, and the short circuit, wherein the first circuit and the second circuit are detachably joined through the coils.

A method for charging a battery based on an alternating voltage produced in a second coil of a transformer, wherein the second coil includes a pair of terminals, the method comprising steps of:

• increasing the alternating voltage produced in the second coil with a booster circuit;
• rectifying the alternating voltage increased by the booster circuit into a direct current voltage with a rectifier circuit, the rectifier circuit applying the direct current voltage to the battery for charging;
• monitoring the direct current voltage produced by the rectifier circuit to determine if the direct current voltage exceeds a predetermined value;
• generating a drive signal when the direct current voltage exceeds the predetermined value, as determined by the monitoring step;
• and
• short circuiting the terminals of the second coil in response to the drive signal.

A method for charging a battery, the method comprising steps of:

• converting a direct current from a direct current power source into an alternating current with an inverter;
• applying the alternating current generated by the inverter to a first coil of a transformer such that a second coil of the transformer produces an alternating voltage;
• increasing the alternating voltage produced in the second coil with a booster circuit;
• rectifying the increased alternating voltage produced by the booster circuit into a direct current voltage with a rectifier circuit;
• applying the direct current from the rectifier to a battery for charging;
• monitoring the direct current voltage from the rectifier circuit to determine if the direct current voltage is equal to or higher than a predetermined permissible voltage;
• and
• short-circuiting a pair of terminals of the second coil when the direct current voltage is equal to or higher than the predetermined permissible voltage, as determined by the monitoring step.