Braun Aktiengesellschaft

Braun Gmbh

Braun Aktiengesselschaft

Gerhard Lang

Jurgen Wolf

Gerhard E Schwarz

Kurt Pittroff

A self-oscillating buck converter includes a controllable switch, a device for controlling the controllable switch, a device for sensing the output voltage of the buck converter, a device for sensing the output current of the buck converter, and a device for sensing the input voltage of the buck converter. The control device controls the controllable switch in such fashion that the output current level varies in dependence upon the output voltage and the input voltage.

Output Controlled Buck Converter

The invention is directed to an electrical device in which an electrical load is powered by a battery via an electronic switching device. A display means serves the function of indicating the charge status of the battery, and a time measurement means determines the connection time of the load to the battery. Following expiration of a predetermined connection time of the load to the battery, when the display means indicates the charge status 'zero', the time measurement means will disconnect the electrical load from the battery by means of the electronic switching device.

Apparatus for controlling battery discharge

Electronic switched-mode power supply for supplying power to an

Charge status indicator

Circuit arrangement for automatically decreasing the load current

Circuit arrangement to detect a voltage

The invention is directed to a discharge indicating means for a storage battery (B) in which a choke (L) and a first transistor (T1) are connected to the storage battery via a switching device (S). The base of a second transistor (T2) arranged between the base of the first transistor (T1) and reference potential is controlled such that the circuit arrangement will start oscillating and an indicating device connected in parallel with the first transistor (T1) will light when the battery voltage (UB) has dropped below a predetermined threshold.

Discharge indicating means for a storage battery

The subject of the invention is a circuit for monitoring the charge state of a battery for supplying voltage to an electrical consumer through a mode selector switch which may be switched from an OFF-state for disconnecting the electrical consumer from the battery into an ON-state for connecting the electrical consumer with said battery whereby in said ON-state different modes of operation of said electrical consumer are possible. The charge state of the battery is determined when the mode selector switch is in the ON-state and, when the voltage drops below an adjustable threshold value, an acoustic and/or optical indication is triggered after the electrical consumer is switched off. The circuit in the ON-state consumes only a very slight amount of energy and no additional energy in the OFF-state. In addition to the mode selector switch for switching the electrical consumer on and off, no battery test button or additional battery test position of the mode selector switch is required.

Method and circuit for optical and/or acoustic indication of the charge

A battery charging circuit having an electromagnetic transformer with primary and secondary coils, a rectifier connected between the secondary coil and the battery, a first transistor connected in series with the primary coil and a resistor to form a circuit in parallel with a power source, the base of the first transistor being connected to the secondary coil, and a second transistor electrically connected to the base of the first transistor. The first transistor has a high switching frequency, and the battery is charged with a constant reverse current during its blocking phase, regardless of the power source voltage. The first transistor is protected from reverse kick-back voltage pulses induced during its blocking phase by the provision of a diode and Zener diode connected in series across the primary coil and a capacitor interposed between the secondary coil and the base of the first transistor.

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Altweilnau, Germany

Gerhard Lang