Abstract: A charging apparatus having a power supply circuit that provides a DC output current via a sense resistor. A current detector amplifies, detects and provides a voltage across the sense resistor. A controller designates the output of the current detector as a determination signal when the DC output current is equal to a preset voltage. Responsive to the determination signal, the controller generates a control signal in order to control the DC output current of the power supply circuit. More particularly, the current detector includes a first differential amplifier that amplifies and output the voltage across the sense resistor, a second differential amplifier amplifies and supplies a differential voltage between the output of the first differential amplifier and a predetermined first reference voltage, and a first output circuit responsive to the output of the second differential amplifier delivers the determination signal.

Abstract: In a self-oscillating power-supply circuit for charging a battery (B) the switching transistor (T2) is turned off if the voltage across the sensing resistor (R3) exceeds the threshold voltage of a zener diode (D5). Instead of the zener diode (D5) it is possible to use a switching transistor which is actuated when the current through the switching transistor exceeds a given value. A diode (D6) is arranged in series with the zener diode (D5) and can be short-circuited by means of a switch (T3) in order to switch the power-supply circuit from slow charging to rapid charging. A voltage sensor may be added to monitor the battery voltage and to eliminate the short-circuit of the diode (D6) when a given battery voltage is reached, as a result of which the power-supply circuit changes over to slow charging.

Abstract: In a self-oscillating power-supply circuit for charging a battery, the main switching transistor is turned off by a second switching transistor (T2) of an opposite conductivity type, which is arranged in series with the main switching transistor (T1) via a sensing resistor (R8). This configuration allows rapid switching of the main switching transistor (T1). The power-supply circuit can be turned on and off in a simple manner (R7, T4). Moreover, it is simple to provide a compensation (R4) for varying mains voltages, an auxiliary voltage (D6, C4) for powering additional circuits (R9, R10), which auxiliary voltage also remains available when the power-supply circuit is turned off.

Abstract: A low cost load sensing technique that is suitable for use in sensing batteries in a battery charging circuit is disclosed. The circuit is adapted to be utilized in conjunction with a power supply which may include a primary converter and a voltage feedback circuit. A transformer with a dual secondary winding is connected between the primary converter and the output terminals of the charging circuit. When no load or battery is present, a first feedback loop is utilized with both of the secondary transformer windings in series, which supplies a constant output voltage at the output terminals. When a load is present, a second feedback loop is utilized which includes one of the secondary windings to provide the voltage of the output terminals. A capacitor is connected in parallel with the other secondary winding. When a load is present, a step increase in voltage occurs across the capacitor due to the fact that the both secondary windings are in phase when a load is present.

Abstract: A self-oscillating buck mode battery charger apparatus 10. The apparatus 10 includes a main switching transistor 22, a first control transistor 34 and a second control transistor 36. The control transistors 34 and 36 are arranged such that neither control transistor sees the full input mains voltage across input terminals 12 of the apparatus 10 when the switching transistor 22 is turned off. An alternative embodiment of the invention includes a high and low main sensing circuit 102 in which a controller 120 is used to detect an excessively high mains voltage condition as well as an undesirably low mains voltage condition. The controller 120 turns off a PWM control circuit 104 when either condition is present for a predetermined length of time. Turning off the PWM control circuit 104 causes the main switching transistor 106 to be turned off, thereby preventing damage to the components of the charger apparatus 100.

Abstract: A method of charging and/or transferring charge between a multiplicity of accumulators connected in series, the method includes connecting at least one electrical storage device in parallel to the accumulators on a cyclic basis. The electrical storage devices are made up of transformer elements which are charged by the accumulators. During charging operations, the at least one electrical storage device is switched, on a cyclic basis, as the secondary coil of a transformer, a powered coil wound on the same core acts as the primary coil. During charge-transfer operations, the at least one electrical storage device is switched, on a cyclic basis, as a transmission coil in which a voltage is induced from the whole battery of accumulators, or one or more individual accumulators.