Licentia Patent-verwaltungs Gmbh

Temic Telefunken Microelectronic Gmbh

Telefunken Electronic Gmbh

Karl-Diether Nutz

Dieter Hanselmann

Helmut Moser

Berthold Gruber

Bernd Mayer

Stepfan-Peter Weller

Willy Frank

The invention relates to a charging method for storage batteries, in particular for NiCd and NiMH cells. According to the invention, the rise in the charging voltage during each of a number of consecutive charging cycles of a specified duration is measured in the form of a unit corresponding to a certain voltage. The number of these units is transmitted in the form of a counting pulse to two up-down counters during the period of the charging cycle, whereby one counter functions in the down mode and is set at the beginning of a charging cycle to a number corresponding to the number of units established in the preceding charging cycle. In the following charging cycle, the roles of the two counters are reversed, so that the up-counter is now set to the down mode and the other counter to the up mode, whereby the latter is set to a Certain starting counting status. At the end of each charging cycle, the final status of the down counter is compared with the specified starting status, from which a switch-off criterion is derived for the charging process. According to the invention, this process enables both positive and negative changes in the dU/dt value of the charging curve to be detected with a high voltage resolution and, at the same time, minimal cost.

Charging method for storage batteries

A charging method for storage batteries, in particular for NiCd and NiH cells. In accordance with the invention, the charging operation is cyclically interrupted for the purpose of measuring the charging voltage. During these measurement intervals, the charging voltage is cyclically compared with a reference value. If the value of the actual charging voltage is greater than this reference value, the latter is increased by a certain amount to match it to the actual value of the charging voltage and then stored. By contrast, the number of measurement cycles is counted in which the value of the measured charging voltage is consecutively equal to or less than the maximum stored reference value. Finally, the charging current source is switched off or the charging current is reduced at a preset counter reading. As a result, maximum utilization of the available effective capacity together with extensive protection against overcharging is achieved. In addition, the method in accordance with the invention ensures the inexpensive provision of a charging circuit.

Method and apparatus for charging storage batteries to full capacity

A circuit array, adapted to be coupled to a load and a source of a main AC voltage, for reverse phase angle control whereby a current flow in the load is limited to a defined phase angle (.alpha.) of the main AC voltage, comprising the following components for sequential control of the reverse phase angle control: a switching element, connected to the load and coupled to the source of the main AC voltage, for actuating the current flow in the load; a time determining component; and an integrated circuit. The integrated circuit includes: an actuating circuit, connected to the time determining component, responsive to a first control signal for generating a ramp voltage, and responsive to a second control signal for selecting one of at least two predetermined temporal voltage curves for the ramp voltage; a synchronizing circuit, coupled to the source of the main AC voltage and connected to the actuating circuit, for detecting a zero crossing of the main AC voltage, for synchronizing the ramp voltage to the main AC voltage, and for generating the first control signal; an evaluation circuit, connected to the actuating circuit and the synchronizing circuit, for monitoring the ramp voltage during reverse phase angle control and for generating the second control signal and a third control signal; an output stage, connected between the evaluation circuit and the switching element, and responsive to the third control signal for controlling the switching element; and a voltage supply circuit.

Circuit array for limiting a load current by reverse phase angle control

A squaring circuit and an i.sup.2 t circuit utilizing the squaring circuit. The squaring circuit comprises a voltage-controlled oscillator and a frequency/current converter which are connected to one another, with the input voltage signal being supplied to the voltage-controlled oscillator and to the frequency/current converter on the one hand, and with the output voltage signal being tappable at an RC network connected to the output of the frequency/current converter on the other hand. The value of the output voltage is proportional to the square of the value of the input voltage. With this squaring circuit, it is possible to construct an i.sup.2 t protective circuit for protection of an electrical consumer from overload.

Squaring circuit

A circuit for detecting current flow in a triac, wherein the circuit operates with only one operating voltage with one pole of this operating voltage being connected to a current terminal of the triac and simultaneously being the voltage reference point for the triac. The triac gate voltage fluctuating around the voltage reference point is used to detect the triac current flow, the gate voltage of the triac is transformed, if necessary, into the voltage range of the operating voltage of the detector circuit, and digital information is generated as a function of the gate voltage to indicate whether a load current is flowing in the triac or not.

Circuit for detecting the current flow of a triac

A zero voltage switch comprises two parallel connected current branches for taking over the D.C. current from a D.C. current source in half cycles of an A.C. voltage and a third current branch for blocking the other two current branches in zero axis crossing phases of the A.C. voltage so as to produce control pulses, a logic unit being provided for controlling the D.C. current source whereby an extremely small current is provided up to the beginning of a first control pulse, an increased current is provided during the control pulses and an intermediate current is provided between the control pulses.

Zero voltage switch

A constant current switch for controlling a generally constant switchable load current with fluctuating voltage comprises a first transistor connected in to the current branch of the load circuit and having a voltage divider in parallel to its control path for measuring its control voltage and a second transistor connected to the control input of the switch and to the voltage divider.

Constant current switch

A discriminator circuit is arranged to emit a defined output signal when a certain value of a variable direct supply voltage is reached. The discriminator circuit comprises a current mirror circuit in the form of a first transistor connected to the supply voltage source and arranged to divide an input current into two current branches by means of two collector electrodes. One current branch comprises a Zener diode and a first resistor and this branch is connected to a limiter circuit for limiting the rise in the supply voltage to a predetermined maximum value and the other current branch comprises a second resistor and a second transistor for emitting an output signal from the discriminator circuit.

Discriminator circuits

A window discriminator or voltage range sensor has an input for receiving a d.c. voltage to be sensed and an output for providing a signal when the voltage at the sensor input falls within a predetermined range. The sensor employs a differential switch which has first and second inputs and an output which is coupled to the sensor output. A biasing arrangement is coupled with the first input and is adapted to provide a bias voltage which is substantially independent of the voltage at the sensor input. A circuit is coupled between the sensor input and the second input to the differential switch and is arranged to provide at the second input a voltage related to the sensor input voltage, which voltage effects switching of the differential switch to one state when the d.c. input voltage reaches a predetermined lower level and to the other state when the voltage reaches a level determined by the bias voltage.

Window discriminator or voltage range sensor

An oscillator for producing rectangular pulses comprises a Schmitt trigger controlled by an R.C. element connected in series, a constant current source for charging up the capacitor and a current image circuit for ensuring that the discharge current of the capacitor is consistent with its charging current.

Schmitt trigger square wave oscillator

In the control of power supplied to a load from an a.c. power source by varying the phase angle of the a.c. power alternation at which conduction is initiated, conduction triggering pulses are generated by the use of a single capacitor which is first charged at a selected rate starting from a time corresponding to a predetermined phase angle of the a.c. power alternation, until the voltage thereacross reaches a first value, whereupon a triggering pulse is initiated, and the capacitor is then charged at a selected rate until the voltage thereacross reaches a second value, whereupon the triggering pulse is terminated.

Phase control of power to a load using a single capacitor

A zero axis crossing detector for integrated bipolar circuits comprising two current paths connected in parallel to the input for the alternating current signal, for receiving direct current alternately in each path in dependence on the positive and negative half cycles of the alternating current signal and blocking both current paths during zero phases of the alternating current signal, a contant current source providing a direct current output across the paths during positive and negative half cycles and a transistor in each current path connected in a current mirror circuit and connected to provide the same current values of the current supplied by the constant current source in both current paths.

Zero axis crossing detector

A reference source for producing a current independent of temperature comprises a constant current source which feeds two parallel connected current branches each including a Zener diode of a different Zener voltage, one or more diodes driven in the forward direction in the branches, a transistor forming part of a current mirror circuit and having an output voltage across its collector-emitter path substantially determined by the difference in the Zener voltages, and a transistor circuit to which the output voltage of the above transistor is fed. The transistors of the transistor circuit and the diodes are selected so as to render the output current of the reference source independent of temperature with the assistance of the current mirror circuit.

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Oedheim, Germany

Karl-Diether Nutz