Abstract: There is proposed a control unit for an internal combustion engine, which comprises a boost circuit, a switching element, a current detecting resistor and a controller and is designed to be actuated such that the boost circuit is used to boost a power source voltage to create a boosted voltage and the controller is used to control the switching element so as to enable the boosted voltage to flow to the injector solenoid coil. This control unit is designed such that, when the boost circuit goes out of order, the injector solenoid coil is excited by making use of the power source voltage without using the boosted voltage and without creating a peak current to thereby generate a first holding current required for opening the injector and a second holding current required for retaining the opened state of the injector, the second holding current being lower in intensity than the first holding current.

Abstract: A solenoid-operated valve controller includes a first signal line and a second signal line, which are connected respectively to ends of a first solenoid coil and a second solenoid coil. The first solenoid coil and the second solenoid coil have other ends, which are electrically connected in common to a switch. One of the first and second solenoid coils, which corresponds to signal states of a plurality of input signals that are supplied respectively to the first and second signal lines, is selected, and the switch is turned on and off to control the selected one of the first and second solenoid coils.

Abstract: A normally closed solid state power relay with an optionally optically coupled input circuit at an input terminal with a driver circuit electrically coupled to input terminal to drive one or more a power transistors, preferably MOSFET transistors so that the power transistor is held in the on state by the driver when no voltage or a low level voltage is applied to the input terminal, and the power transistor is held in the off state by the driver when a high level voltage is applied to the input terminal. An energy storage device, a battery or capacitor, is coupled to the driver to powers the driver with the energy storage device being charged by energy from the input terminal when said input terminal when a high level voltage is applied to the input terminal. The energy storage device is charged by leakage current through a diode or through a resistor from the input circuit when the input circuit is in a high state.

Abstract: A method for controlling the operation of a solenoid (14), in which solenoid the movement of the plunger is caused by bringing electric energy to the solenoid, whereby an electric current flows through the solenoid, the method comprising the following steps. defining a model (6) for describing the current signal of the solenoid at certain time intervals from the activation moment of the solenoid onwards, measuring the true current signal (7) of the solenoid at time intervals corresponding with the model, defining a residual signal (8), which is the remainder between the signal of the model (6) and the true current signal (7), and performing a threshold analysis (25) for the residual signal.

Abstract: A fluid dispenser having a dispensing valve movable between open and closed positions for controlling the flow of the fluid from the fluid dispenser. A solenoid is operatively connected to the dispensing valve and is capable of moving the dispensing valve between the open and closed positions. The fluid dispenser further includes a power supply having a voltage and a driver circuit electrically connected to the solenoid and the power supply. The driver circuit provides an output signal to the solenoid having a time variable component, for example, a peak current duration, determined as a function of the voltage of the power supply. Thus, the driver circuit automatically adjusts to, and can be used with, power supplies of different voltages. The invention further includes a method by which the driver circuit provides the output signal as a function of the power supply voltage.

Abstract: When a power source voltage is applied to a switch control section, a control signal is supplied from the switch control section to a transistor. The transistor is placed in an ON state during a period of time corresponding to a pulse width of the control signal. The power source voltage is applied as a first voltage to a solenoid coil. On the other hand, when supply of the control signal to the transistor is stopped, the transistor is placed in an OFF state. A voltage-generating section generates a DC voltage, which is lower than the power source voltage. The transistor applies the generated DC voltage as a second voltage to the solenoid coil.

Abstract: A power switching control apparatus for acquiring pieces of making operation time information of individual phase switches more precisely according to loads and making instants. Making operation time information detecting means outputs the making operation time information of at least one of individual phase switches on the basis of the motion of the movable contact of the phase switch, and outputs the making operation time information of at least another of the individual phase switches on the basis of the phase current of the phase switch. Moreover, the making operation time information detecting means outputs the making operation time information ITA, ITB and ITC of an A-phase switch, a B-phase switch and a C-phase switch individually on the basis of either the detected output of a contact operation sensor and the detected output of a phase current sensor.

Abstract: A method and a device for triggering an injector are described, allowing expansion of the metering range of the injector. The injector is triggered by a trigger voltage that is adjusted according to a predefined voltage for opening the injector, the trigger voltage being first increased to open the injector, starting from the predefined voltage, and then reduced after a predefined time. The predefined time is selected in such a way that the energy stored in an energy accumulator mechanism of the injector has reached a steady-state energy level after the predefined time.

Abstract: The present invention is disclosed by that the power source device with variable output voltage is operatively controlled by the switching device to provide higher voltage power to the driving coil installed in the electromagnetic actuating device so as to produce larger electromagnetic effective force, wherein the power source device with variable output voltage after actuation is operatively controlled by the switching device to be switched to provide lower voltage power thus allowing smaller current to pass through the driving coil thereby holding electrification for excitation, while required operating characteristics of the electromagnetic actuating device can still be ensured.

Abstract: At least two sets of driving coils of the same individual electromagnetic actuating device of the present invention in parallel connection or series-parallel connection to appear relatively lower impedance being electrified to obtain larger actuating force is further manipulated by the switching device to be switched to series connection and series-parallel connection to appear relatively higher impedance thus reducing currents passing through driving coils, while required operating characteristics of the electromagnetic actuating device can still be satisfied.

Abstract: A system and method for controlling electromechanical valves operating in an engine is presented. According to the method, valve operation can be improved by heating the valves, at least during some conditions.

Abstract: An operative control circuit of multiple electromagnetic actuating devices in series and parallel connections, wherein individually installed driving coils of two or more than two electromagnetic actuating devices being operatively controlled by a switching device to appear lower impedance in parallel connection or series and parallel connection for electrification thereby producing a larger electromagnetic actuating power is switched to appear relatively higher impedance in series connection or series and parallel connection thereby reducing currents passing through driving coils while required operating characteristics for individual electromagnetic actuating devices after electrification are still satisfied.

Abstract: An electromechanical solenoid control system with reduced hold current includes an electromechanical solenoid including an armature and a coil; a voltage source; a resistor placed in an electrical line between the voltage source and the solenoid coil; a switching device configured to selectively apply power from the voltage source to the solenoid coil; and a control element connected electrically to the switching device, the control element operable to receive a signal from the electrical line and use the signal to control the switching device to selectively apply power from the voltage source to the solenoid coil.

Abstract: A solenoid-operated valve device is provided which includes a valve, a solenoid actuator designed to be supplied with electric power from a battery to operate on voltage substantially identical with that outputted from the battery to move the valve, and a controller working to energize said solenoid actuator. Prior to entering a main energization mode to energize the solenoid actuator to open or close the valve, the controller works to supply a low current to the solenoid actuator to create magnetic field therein to assist in energizing the solenoid actuator in the main energization mode quickly at a high speed. The controller may alternatively be designed to step-up the voltage to be applied to the solenoid actuator initially prior to entering the main energization mode.

Abstract: An amperage control for an electrically operated valve having a coil. A process control apparatus generates a plurality of electrical operating data signals, each signal corresponding to an operating parameter of the valve. A valve control apparatus transmits voltage to the coil of the valve to control the operation of the valve, the valve control apparatus receiving at least one operating data signal generated by the process control apparatus. A current flow is created in the coil of the valve upon receiving voltage from the valve control apparatus. A current senses the flow of current in the electrically controlled valve, and creates an electrical signal responsive to the current flow in the coil of the valve. When the signal created by the current sensing apparatus is applied to the valve control apparatus, the valve control apparatus modifies the operation of the valve responsive to the signal created by the current sensing apparatus.

Abstract: An injector drive device includes a power supply unit that is supplied with power from a battery mounted in a vehicle and generates a voltage higher than the voltage of the battery, and EDU having a drive unit that is supplied with power from the power supply unit and drives an injector. The drive unit is housed in a housing. The power supply unit is placed externally to the EDU, that is, externally to the housing, so that the housing need not be made large against heat generation of the power supply unit.

Abstract: A dual coil half bridge converter adapted to be coupled to a dual coil actuator of a cylinder valve in an internal combustion engine is described. In one example, the converter has a first and second capacitor and a voltage source, where the converter is actuated via switches to individually energizing coils in said dual coil actuator. A voltage regulator is also shown for maintaining midpoint voltage during unequal loading of different actuator coils in the converter.

Abstract: A method and apparatus for operating a magnetic actuator in a power switching device by transmitting at least two different electrical current waveforms to the actuator. Both waveforms are sent to the actuator from a controller in the same direction to move an actuator's armature from a first position to a second position. The first current waveform causes the armature to move from the first position to the second position. The second waveform is transmitted to the actuator to keep the armature moving towards the second position without overdriving the armature.

Abstract: The present invention provides a system and method for controlling a solenoid that ensures accurate timing between the enabling of the driving circuit and the activation of the solenoid, while simultaneously providing a two energy level driving scheme to reduce power consumption. The present invention utilizes a single enable signal and supplies the solenoid two different energy levels, a higher “set” level and a lower “hold” level. The generation of these two levels is based on the enabling signal and guarantees that the higher “set” level is present when the solenoid is activated, thereby minimizing undesirable timing jitter.

Abstract: With a method for operating an internal combustion engine with a fuel injector (18) that is opened and closed electrically, a booster capacitor (BK) serving to increase the current intensity when the fuel injector (18) is opened, reliable fuel injection is ensured, even in extreme cases, such as resumption of fuel injection after an overrun condition, and in a starting procedure after a shutoff phase that is accompanied by an increase in pressure in the high pressure fuel system due to the fuel heating up, when booster capacitors are used that were designed for normal operation, by switching the current profile in certain operating states of the internal combustion engine from a standard value to an increased value and/or to a longer duration and, when the certain operating state ends, by resetting it to the standard value and the standard duration.

Abstract: Systems, apparatuses and methods for controlling valves through controlled power escalation towards the actuation threshold of the valve. A power signal is applied to a control input of a valve at a level less than a valve switch threshold at which the valve will be actuated. The power to the control input is then progressively increased. The valve is actuated when the power signal eventually reaches the valve switch threshold, thereby actuating the valve using a power signal commensurate with the actual valve switch threshold of the particular valve and its current operating conditions.

Abstract: An electromagnetic actuator comprises a yoke, a core, at least two windings and switching means of the windings from a series position to a parallel position and vice-versa. It comprises control means comprising regulating means of the electric current flowing in the windings. The control means comprise inrush means controlling the voltage supplied to the windings during a closing operation, and controlling the switching means to place the windings in parallel mode. The control means also comprise holding means controlling the current supplied to the windings during a holding operation of the actuator in the closed position and controlling the switching means to place the windings in series mode.

Abstract: The present disclosure is directed to systems and methods for controlling energy consumption in a system having a battery and including a controller and one or more solenoids. In accordance with the disclosure, the controller provides a controlling mechanism, such as a control algorithm, that will provide the necessary power to operate the one or more solenoids throughout the range of battery voltage in a manner that optimizes the voltage discharge from the battery and simultaneously maximizes battery life. Further power conservation measures are implemented by using a controller and an associated control algorithm to operate a solenoid throughout the range of battery voltage in a manner that places the discharge of the battery in reduced power consumption operating modes as the capacity of the battery is reduced.

Abstract: A solenoid test device includes a clock circuit, a control circuit, and an output port configured for coupling to two ends of a solenoid. The clock circuit generates a clock signal and sends it to the control circuit. The control circuit periodically and alternately couples one of the two ends of the solenoid to ground via the output port under the control of the clock signal. The solenoid test device is used to generate a periodic control signal to test service life and stability of solenoids.

Abstract: By switching the NMOS (11) on and off, a drive current passes through a solenoid (15). The drive current passes through a conversion circuit (16), and an amplifier circuit (17) outputs a current detection result by amplifying the output voltage of the conversion circuit (16). Because a plurality of resistor elements (161 to 16n) that constitute the conversion circuit (16), together with elements that constitute the amplifier circuit (17) are formed diffused to a semiconductor substrate (100), even if the attribute changes by the conversion circuit (16) generating heat, by the drive current, the amplifier circuit (17) becomes approximately the same temperature, and the attribute changes. Therefore, a highly accurate current detection becomes possible without using components for temperature correction.

Abstract: A coloring apparatus 1 includes a coloring nozzle 31 for spouting a coloring material, a signal generator 53, and a controller 19. The coloring nozzle 31 includes an electromagnetic valve 51. The signal generator 53 outputs signals for spouting the coloring material from the coloring nozzle 31 to both a CPU 62 of the controller 19 and a driving circuit 64. The CPU 62 outputs a signal for keeping the electromagnetic valve 51 open to the driving circuit 64 when a frequency of the signals from the signal generator 53 is higher than a specific frequency. When at least one of the signals from the CPU 62 and the signal generator 53 is inputted, the driving circuit 64 applies a spike voltage A and then applies a hold voltage B to a coil 40. While at least one of the signals from the CPU 62 and the signal generator 53 is inputted, the driving circuit 64 applies a spike voltage A and then continuously applies a hold voltage B to a coil 40.

Abstract: A method is provide for controlling an inductive load device (ILD). The method includes providing a voltage potential across ILD and disabling a flow of current through the ILD resulting from the voltage potential across the ILD when a voltage across a sensing device rises to substantially equal an upper threshold value. The rate at which the voltage across the sensing device rises is a function of resistive and inductive characteristics of the ILD. The method additionally includes enabling the flow of current through the ILD resulting from the voltage potential across the ILD when the voltage across the sensing device decays to substantially equal a lower threshold value. The rate at which the voltage across the sensing device decays is a function of the resistive and inductive characteristics of the ILD.

Abstract: A control circuit for an electromagnetic drive includes first and second electronic switching elements, which in conjunction with a timing element subject the drive coil to a corresponding direct current in the starting phase or in the maintenance phase. A starting current and a maintenance current are provided by means of a current source that is controlled by the timing element and a direct current converter with downward control.

Abstract: A first voltage-to-current converter converts a difference voltage between a command voltage and a reference voltage into a current. A second voltage-to-current converter converts a difference voltage between a positive output terminal and a negative output terminal of a PWM drive apparatus into a current. A low-pass filter is connected to a connection point between an output terminal of the first voltage-to-current converter and an output terminal of the second voltage-to-current converter. An amplifier amplifies a difference voltage between a voltage at the connection point and a reference voltage. A PWM modulator PWM-modulates an output voltage of the amplifier. A drive section drives a load in accordance with an output signal of the PWM modulator.

Abstract: In a direct-current voltage-driven magnetic contactor, a main contact is in an open circuit condition in an attraction period of an initial period of excitation by an operating coil, and in a closed circuit condition in a subsequent holding period, and a drive circuit includes a direct-current power supply voltage detecting circuit that gives a start signal when an applied voltage of a exciting direct-current power supply exceeds a predetermined value, a first drive circuit that makes a starting semiconductor switching element perform an ON operation on receiving the start signal, and a second drive circuit that makes a current limiting semiconductor switching element perform a switching operation when a terminal voltage of a charging capacitor reaches the predetermined value.

Abstract: In a method for operating an internal combustion engine with an electrically openable and closable fuel injector (18), the injectors are reliably held open in all operating conditions by the fact that the holding current for an open valve (18) is switched from a standard value to a higher value in certain operating states of the internal combustion engine, and it is reset to the standard value when the certain operating condition has ended.

Abstract: A potential of an end of the coil is inputted to a plate-OFF detecting portion which detects OFF-tendency in which a plate of a relay is about to get apart from a head of a core of the relay. When the OFF-tendency is detected, a coil current for supplying a coil of the relay is set to a first current value with which a plate of an electromagnetic relay is drawn and a movable contact of the relay comes in contact with a fixed contact of the relay. When an external disturbance ends, the coil current is returned to a second current value, which is smaller than the first current value, so that the movable contact and the fixed contact are kept in contact with each other.

Abstract: The present invention is related to a device for the control of electrically excited magnetic load such as electromagnetic braking device, electromagnetic clutch, electromagnetic switch, electromagnetic relay, electromagnetic valve, electromagnetic iron, electromagnetic lock, and toroidal coil, etc., or driving coils installed on the excited windings of electromotor or generator, for the full voltage actuation and reduction of excited winding voltage and for sustaining the operation of electrical excitation through the reduction of voltage for saving of energy.

Abstract: There is described a method of operating a device (1) controlling electric actuators (3), and having a pair of input terminals (4, 5) connected to an electric energy source (6, 10); a number of pairs of output terminals (7, 8), between each of which a respective electric actuator (3) is connected in use; and controlled switches (11, 12) for connecting the electric actuators (3) to the electric energy source (6, 10) independently of one another; the method including the step of controlling the controlled switches (11, 12) to supply an electric current to the electric actuators (3) via the electric energy source (6, 10).

Abstract: Prior to the operation of a solenoid type of fuel injector, a DC voltage is applied across the injector to create a current through the injector that is below the activation current of the injector. A capacitor is then placed in series with the injector and the flyback energy from the injector transfers a charge onto the capacitor. When the injector current drops to a predetermined level, the capacitor is removed from the circuit and isolated. This process is repeated until a minimum charge is on the capacitor. By placing the capacitor charge onto the injector at the time that the injector is to be activated, the opening response of the injector is improved. By applying the charge on the capacitor to the injector in a manner to neutralize the eddy currents when the voltage across the injector is removed, the closing response is improved.

Abstract: A solenoid (30) has one end connected to the ground G and the other end connected to an N-MOS transistor (33) which applies current from a battery (31) to the solenoid (30). On the other hand, regenerative current generated when the N-MOS transistor turns off flows from a diode (34) whose anode is connected to the ground, via a resistor (32) to the solenoid (30). Accordingly, without connecting the anode of the diode (34) to the solenoid (30) using a lead line, the solenoid (30) can be driven by current. Moreover, since the current flowing from the battery (31) to the solenoid (30) does not flow to the resistor (32), heating is reduced and a solenoid drive apparatus can be made in an IC.

Abstract: A drive control circuit supplies power to a solenoid coil in an in-cylinder injector of a cylinder in response to a fuel injection signal. A failure detection circuit to detect disconnection failure at an in-cylinder injector is arranged to be shared among cylinders whose phase of each stroke differs 360 degrees in crank angle. An engine ECU detects failure including identification of the injector with disconnection failure based on a failure detection signal from the failure detection circuit, and a crank angle detected by a crank angle sensor. The driver is notified of the failure detection result through the engine ECU.

Abstract: Methods and circuits for driving a coil-armature device are disclosed. The circuits are configured to drive the coil-armature device to a first energy level for a period of time sufficient to retract the armature to the center of the coil, and then, to drive the coil-armature device to a second energy level subsequently. The first energy level is greater than the second energy level. The second energy level may be achieved by alternatively connecting and disconnecting a driving voltage to the coil-armature device according to a “hold” mode duty cycle. The first energy level may be achieved by connecting the driving voltage to the coil-armature device continuously for a period of time sufficient to retract the armature to the center of the coil. Alternatively, the first energy level may be achieved by alternatively connecting and disconnecting the driving voltage to the coil-armature device according to a “pull-in” mode duty cycle, which is different from the “hold” mode duty cycle.

Abstract: A driving unit of the present invention comprises a moving element, an elastic body configured to support the moving element, a permanent magnet fixed on said moving element, an electromagnet disposed to be opposed to said permanent magnet, and a controller. The moving element and the elastic body constitute a resonance system. The electromagnet includes a magnetic material and a coil wounded around the magnetic material. The controller magnetizes the magnetic material by feeding a current through the coil and gives a vibration force to the moving element by magnetic force acting between the magnetic material and the permanent magnet. The feature of the present invention resides in that the controller determines a current waveform necessary for an intended motion of the moving element, and applies a voltage to the coil intermittently so that a current in the form of the current waveform flows through said coil.

Abstract: A PWM controller for a bridge driver circuit for controlling current in an inductive load such as a motor, can set the driver into a forward mode, a slow decay mode or a fast decay mode, and can switch from slow decay mode into forward mode or into fast decay mode for the duration of pulses at controlled time intervals to provide pulse width modulated control of the current. This is a simpler control scheme avoiding complex switching schemes related to mixed mode decay. By using a controlled PWM frequency, it is easier to avoid the problems of variable frequency such as increased heat dissipation or acoustic noise generation. It can have a selector for selecting top or bottom sense switching, enabling a wider range of stable PWM duty-cycles to be used (e.g. 0% to 100%), which is useful to compensate for Back emf influence on coil-drive.

Abstract: A relay device includes plural relay units, each having a coil for opening/closing a contact point, a base plate made of resin and having wiring metal pieces, and a control circuit mounted on the base plate for controlling current supply to the coil. The control circuit has a function of stabilizing the holding current irrespective of environmental variation. Thus, the holding current can be further reduced and heating and power consumption can be reduced without losing the function of keeping the contact point state.

Abstract: A solenoid control circuit that includes two switching networks that are selectively opened and closed in a current limit cycle to control the magnitude of the current flowing through the solenoid. The configuration of the switching networks is such that current flows through an energy dissipating resistor only when the solenoid is commanded off by the solenoid control circuit, and not during the current limit cycle. Thus, the energy dissipated by this resistor is reduced relative to other solenoid control circuits, making it more efficient, and reducing EMI emissions from the circuit while providing for a fast solenoid response.

Abstract: A circuit arrangement and also a method for controlling a bistable magnetic valve in which a magnetic valve is to be supplied with a pulse of electrical current in order to switch over the magnetic valve from a first stable state into a second stable state, comprises a power supply source to provide a supply voltage, a power supply device fed by the power supply source and able to be activated for the duration of the current pulse by an entered control signal (Enable) to create a coil current (I) flowing through the magnetic coil, with the coil current (I) being set to a setpoint, where changeover means are provided in order to reduce the setpoint of the coil current during the current pulse. This advantageously allows the power dissipation of the activation of bistable magnetic valves to be reduced.

Abstract: A linear vibration motor comprises: a stator provided with one of a permanent magnet and an electromagnet including a winding; a vibrator provided with the other of the permanent magnet and the electromagnet and supported to be able to vibrate; a movement detection unit for detecting movement of the vibrator; a control output unit for supplying electric power to the winding of the electromagnet based on an output of the movement detection unit so as to generate vibration of the vibrator; a rechargeable battery for supplying electric power to the control output unit; and a power supply unit for supplying electric power to the control output unit and to the rechargeable battery, wherein the power supply unit supplies electric power in an intermittent mode with synchronized timing such that the timing of the intermittent power supply is synchronized with the timing of the power supply to the winding.

Abstract: A circuit for sensing a current in an inductor is described. Integrator circuitry is operable to generate a first signal representing an integration of a voltage across the inductor. Comparison circuitry is operable to generate a reset signal each time the first signal reaches either a positive or negative threshold. The reset signal is for resetting the integrator circuitry. Logic circuitry is operable to generate a count direction signal indicating which of the positive and negative thresholds was reached to generate the reset signal. Counter circuitry is operable to increment or decrement a count representing the current in the inductor in response to the reset and count direction signals.

Abstract: A control device executes an overlap injection operation, in which one of the plurality of injectors is energized first to inject fuel, and a next one of the plurality of injectors is energized to inject fuel after starting of the energization of the one of the plurality of injectors while the one of the plurality of injectors is still kept energized. The control device corrects an energization period of the next one of the injectors by lengthening the energization period of the next one of the injectors in comparison to a normal energization period of the next one of the injectors, which is set for a non-overlap injection operation of the next one of the plurality of injectors.

Abstract: A description is provided of a device (2) for control of an electro-actuator (3), comprising a first and a second input terminal (4,5) which are connected to an electrical energy source (6); and a first and a second output terminal (10,11) which are connected to the electro-actuator (3). The control device (2) additionally comprises a threshold comparator (30) which can compare the voltage (VHS,VLS) present at the first or second output terminal (10,11) of the control device (2) with a threshold voltage (VTH—EOI) and can generate a signal (VEOI) which is indicative of the instant of end of actuation of the electro-actuator, when this voltage (VHS,VLS) passes through the threshold voltage (VTH—EOI).

Abstract: The present invention provides a system and method for controlling a solenoid that ensures accurate timing between the enabling of the driving circuit and the activation of the solenoid, while simultaneously providing a two energy level driving scheme to reduce power consumption. The present invention utilizes a single enable signal and supplies the solenoid two different energy levels, a higher “set” level and a lower “hold” level. The generation of these two levels is based on the enabling signal and guarantees that the higher “set” level is present when the solenoid is activated, thereby minimizing undesirable timing jitter.

Abstract: A solenoid drive circuit includes a control circuit which comprises a detector with a resistor for discerning current flow therethrough to produce electric signals that correspond to level of current flow through a solenoid connected to the resistor; an amplifier for amplifying the electric signals from the resistor; and an integrator for integrating the amplified output from the amplifier.

Abstract: The invention relates to a method and an apparatus for regulating a current through an inductive load, which can be connected to a power supply, to a prescribed nominal current value, where the method comprises the following method steps: a) turning on and off the power supply in pulsed fashion, with the power supply being turned on when the current (I) flowing through the load (L) reaches a first limit value (I—1), which is below the nominal current value (I_nominal) by a hysteresis value (H), and with the power supply being turned off when the current (I) reaches a second limit value (I—2), which is above the nominal current value (I_nominal) by the hysteresis value (H), b) determining a period duration between two successive turn-on or turn-off times, c) comprising determined the period duration with a given period duration (Tnominal), and d) changing the hysteresis value (H) on the basis of the comparison between the determined period duration and the prescribed period duration (Tnominal).