GB2310328A - Circuit arrangement for current limitation and for overvoltage protection - Google Patents

Circuit arrangement for current limitation and for overvoltage protection Download PDF

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Publication number
GB2310328A
GB2310328A GB9703332A GB9703332A GB2310328A GB 2310328 A GB2310328 A GB 2310328A GB 9703332 A GB9703332 A GB 9703332A GB 9703332 A GB9703332 A GB 9703332A GB 2310328 A GB2310328 A GB 2310328A
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GB
United Kingdom
Prior art keywords
voltage
circuit arrangement
bipolar transistor
field
effect transistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9703332A
Other versions
GB9703332D0 (en
GB2310328B (en
Inventor
Dietmar Klien
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tridonic Bauelemente GmbH
Original Assignee
Tridonic Bauelemente GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tridonic Bauelemente GmbH filed Critical Tridonic Bauelemente GmbH
Publication of GB9703332D0 publication Critical patent/GB9703332D0/en
Publication of GB2310328A publication Critical patent/GB2310328A/en
Application granted granted Critical
Publication of GB2310328B publication Critical patent/GB2310328B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/001—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/062—Avoiding or suppressing excessive transient voltages or currents
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2851—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2856—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against internal abnormal circuit conditions

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Power Conversion In General (AREA)
  • Thermistors And Varistors (AREA)

Description

Circuit arrangement for current limitation and for overvoltage Protection The present invention relates to a circuit arrangement for electronic ballasts having an active harmonics filter for operating gas discharge lamps, which circuit arrangement limits the switch-on current and protects the electronic ballast against overvoltages.
Active harmonics filters contain, as a rule, large capacitors, in particular electrolytic capacitors, which are disposed in parallel with the input connections of the electronic harmonics filter. Said large capacitors are responsible for undesirably high input currents in the electronic harmonics filter.
To limit these high switch-on currents, various circuit arrangements have been proposed which, as is shown in Figure 2, are connected to further components of the electronic ballast.
As a rule, the electronic load comprises a rectifier circuit 2, which is connected to the mains voltage Ums via an arrangement 1 for radio interference suppression. The rectifier circuit 2 converts the input-side alternating voltage Um, ms into a rectified intermediate circuit voltage which is fed via an electronic harmonics filter 4 to the inverter (not shown) of the electronic ballast. The inverter has alternately switching semiconductor switches and consequently generates a high-frequency alternating voltage of variable frequency from the intermediate circuit voltage. The mark-to-space ratio between the switch-on times of the semiconductor circuits of the inverter may likewise be variable, so that the gas discharge lamp driven by the inverter can be dimmed by altering the frequency and/or the mark-to-space ratio. The circuit arrangement 3 for switch-on current limitation and for overvoltage protection is connected between the rectifier 2 and the electronic harmonics filter 4 comprising an electrolytic capacitor C3 described above and converts the voltage Ue supplied by the rectifier circuit into a voltage Ua applied to the harmonics filter 4.
An exemplary known circuit arrangement 3 is described in EP-B1-O 272 514. The circuit arrangement disclosed therein for switch-on current limitation in the case of switched-mode power supply devices comprises a field-effect transistor whose source-drain section is connected between the input connection 5" and the output connection 6" of the circuit arrangement 3.
The gate connection of the field-effect transistor is driven via a delay element in order to delay the charging of the electrolytic capacitor C3. The actual switch-on current limitation and the protection against overvoltage is carried out by a suitable arrangement which contains a current measuring resistor and an amplifier connected thereto. If the voltage occurring across the current measuring resistor is above a certain threshold value, the amplifier switches the field-effect transistor to the off state. The output of the delay element is connected to the gate connection of the field-effect transistor in the form of an OR circuit by means of the output of the amplifier.
The present invention seeks to provide a further switching arrangement for switch-on current limitation in conjunction with an overvoltage protection for an electronic ballast comprising an electronic harmonics filter.
According to the present invention, there is provided a circuit arrangement for electronic ballasts for operating gas discharge lamps, wherein the circuit arrangement is connectable between a supply voltage source and an electronic harmonics filter of the electronic ballast for switch-on current limitation and for overvoltage protection of the electronic ballast, said circuit arrangement comprising: a field-effect transistor, the source-drain section of which is connected between a first output connection of the circuit arrangement and a first input connection of the circuit arrangement, wherein a second input connection is connected directly to a second output connection; a bipolar transistor, the base voltage of which is dependent on the supply voltage via a voltage divider; and a charging capacitor connected in parallel with the gate-source section of the field-effect transistor, and also connected to the collector-emitter section of the bipolar transistor such that the charging capacitor is charged if the bipolar transistor turns off and the base voltage of the bipolar transistor lies below a predetermined base voltage threshold value of the bipolar transistor, until the voltage of the charging capacitor exceeds a gate voltage threshold value of the field-effect transistor at which threshold voltage the field-effect transistor is turned on such that the first input connection of the circuit arrangement is connected to the first output connection thereof via the source-drain section of the field-effect transistor and the charging capacitor discharges and charges an input capacitor of the electronic harmonics filter, and wherein the field-effect transistor remains switched on until the base voltage at the bipolar transistor exceeds the threshold value thereof to turn on the bipolar transistor and thus short circuit the charging capacitor such that the gate voltage of the field-effect transistor falls below the threshold value thereof and the field-effect transistor is turned off until the base voltage dependent upon the input voltage falls below the base voltage threshold value of the bipolar transistor.
In a preferred embodiment, the voltage divider connected to the base of the bipolar transistor comprises a first resistance connected in parallel with the base-emitter section of the bipolar transistor, and having a first end connected to the first input connection of the circuit arrangement and second end connected, (a) via a first resistor circuit and a capacitor, and (b) via a second resistor circuit, to the second input connection, the second resistor circuit comprising a second resistance connected in parallel with the first resistance via a diode.
Preferably, the first output connection of the circuit arrangement is connected via a further diode to the first resistor circuit and the second capacitor, the further diode reducing the voltage across the first resistor circuit and the first resistance if the field-effect transistor is switched on, such that the bipolar transistor is switched off until a voltage supplied to the base of the bipolar transistor via the second resistor circuit and the diode exceeds the base voltage threshold value of the bipolar transistor.
The circuit arrangement may further comprise a heat-sensitive resistance connected in parallel with the source-drain section of the field-effect transistor as protection against voltage peaks.
The charging capacitor is advantageously connected via a third resistor circuit to the collector and emitter of the bipolar transistor and via a fourth resistor circuit to the second input connection and the second output connection of the circuit arrangement.
In a preferred embodiment, the circuit arrangement is connected in use to the electronic ballast such that operation of an inverter or rectifier of the electronic ballast is interrupted by means of a separate overvoltage cutout provided in the electronic ballast if the field-effect transistor turns off and the base voltage of the bipolar transistor exceeds the base voltage threshold value.
As an aid to understanding the invention, a preferred embodiment thereof will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which: Figure 1 shows a preferred embodiment of a circuit arrangement of the invention; and Figure 2 shows a simplified block circuit diagram for clarifying the connection of the circuit arrangement shown in Figure 1 to an electronic ballast.
Figure 1 shows a preferred embodiment of the circuit arrangement 3 of the invention, the main circuit elements being a field-effect transistor T2 serving as switch-on current limitation and as overvoltage protection and a bipolar transistor T1 for driving the field-effect transistor. In the conducting state, the field-effect transistor makes possible charging of an electrolytic capacitor C3 (shown in Figure 2) of the electronic harmonics filter 4 connected to output connections 6' and 6" of the circuit arrangement 3 by means of its connected-through source-drain section. In the off state, the source-drain section of the field-effect transistor T2 is interrupted and the output connection 6" is separated from the input connection 5", so that the input capacitor C3 of the harmonics filter 4 is no longer charged. The operation of the circuit arrangement 3 shown in Figure 1 for switch-on current limitation and for overvoltage protection is as follows: After the mains voltage Umas, has been switched on, the rectifier circuit 2 (cf. Figure 2) causes a half-wave rectified, pulsating direct voltage to be present at the circuit arrangement 3. Since capacitors C1 and C2 shown in Figure 1 are discharged before the mains voltage Umains is switched on, the input voltage Ue tracks the instantaneous value of said pulsating direct voltage.
A resistor R4 is disposed between the base and the emitter of the bipolar transistor T1 as part of a voltage divider circuit, the voltage divider circuit furthermore comprising, on the one hand, resistors R9 and R10 and the capacitor C2 and, on the other hand, further resistors R1, R2, R3 and a zener diode D7.
It can be seen from Figure 1 that the voltage present across the resistor R4 tracks the input voltage Ue indirectly via the voltage divider circuit. Since the voltage dropping across the resistor R4 corresponds to the base voltage of the bipolar transistor TI, it consequently determines the switching behaviour of the latter. If the voltage dropping across the resistor R4 exceeds a certain base-voltage threshold value, as a rule 0.7 V, the bipolar transistor Tl is switched on, as a result of which, on the other hand, the gate voltage present at the field-effect transistor T2 is limited to a voltage value situated below 0.7 V via further resistors R5 and R6 and a further zener diode D3.
If the input voltage Ue, which tracks the pulsating intermediate circuit voltage after the mains voltage Remains, is switched on, drops below a certain threshold value fixed by the resistors R4, R9 and R10 of the voltage divider, ie. if the base voltage of the bipolar transistor Tl present across the resistor R4 drops below a certain base voltage threshold value, the transistor T1, on the other hand, turns off so that the capacitor C1 connected between the gate connection and the source connection of the field-effect transistor T2 is charged via further resistors R7 and R8, the field-effect transistor T2 still being in the off state. If the voltage present at the charging capacitor C1 now exceeds the threshold voltage of the field-effect transistor T2, the latter is turned on and the charging capacitor C1 is short circuited, so that the input capacitor C3 of the harmonics filter 4 is slowly charged via the source-drain section of the field-effect transistor T2, the charging starting in the vicinity of the passage through zero of the mains voltage Umdjn5-With the aid of a diode D2 connected to resistors R9 and R10 as and to capacitor C2, the voltage across these components can be reduced to approach zero, thereby ensuring that the bipolar transistor T1 turns off and, consequently, the field-effect transistor T2 remains conducting.
However, with the aid of the diode D2, the voltage supplied to the resistor R4 via the voltage divider comprising the circuit elements R1, R2, R3 and D1 is not reduced, so that the bipolar transistor T1 again becomes conducting if the input voltage Ue exceeds a threshold value fixed by the circuit components R1, R2, R3 and D1. In this case, as already described above, the gate voltage of the field-effect transistor T2 is reduced to OV, so that the field-effect transistor T2 turns off and serves as overvoltage protection. This state continues to exist until the base voltage of the bipolar transistor T1 drops below the base voltage threshold value again, as a result of which the bipolar transistor T1 is switched back to the basic off state and the field-effect transistor T2 becomes conducting again.
The process described above consequently repeats as a function of the variation in the pulsating input direct voltage Ue, so that an effective switch-on current limitation and an effective overvoltage protection are ensured for the electronic ballast.
It should be noted that, because of the time constant fixed by the resistor R5 and the charging capacitor C1, brief voltage peaks having a duration of not more than 1 us do not activate the overvoltage protection of the circuit arrangement of the invention.
As a further circuit component, a heat-sensitive resistor R11 is connected in Figure 1 between source connection and drain connection of the field-effect transistor T2, which resistor protects the field-effect transistor T2 against brief voltage peaks. For an effective overvoltage protection, it is not necessary to dimension the field-effect transistor T2 in relation to the maximum input voltage Ue which occurs since the output voltage Ua of the circuit arrangement 3 is always reduced with respect to Ue by the magnitude of the drain-source breakdown voltage.
The circuit arrangement 3 of the invention has, as described in detail above, an overvoltage protection. However, if a user mistakenly connects the electronic ballast between two phases, the lamps would continue to burn despite the overvoltage protection so that the incorrect connection of the electronic ballast is not detectable for the user. In this case, the full overvoltage would drop across the field-effect transistor T2 which acts as overvoltage-protection component, which would, however, result in a very high power loss across the field-effect transistor T2. It is therefore proposed in the present invention to provide an additional overvoltage cutout in the electronic ballast, for example in the electronic harmonics filter, which cutout interrupts the operation of the inverter or rectifier of the electronic ballast if the overvoltage protection circuit of the circuit arrangement 3 of the invention is activated, so that high power losses are avoided.
In conclusion, it should be noted that the switch-on current limitation of the invention does not respond to direct current since, in this case, only the capacitor C2 is charged up via the resistors R9 and R10 and is charged after approximately lOOms to such an extent that the voltage supplied via the resistors R9 and R10 to the base resistor R4 of the bipolar transistor T1 is insufficient to turn the bipolar transistor T1 on, so that, accordingly, the field-effect transistor T2 is always conducting and the electrolytic capacitor of the electronic harmonics filter is charged directly and abruptly, without switch-on current limitation, by means of the input voltage Ue. This direct-voltage state may arise, for example, in the emergency operation of an escape-route lamp fitting, only some of the illumination system always being operated, however, in the emergency operation, so that the failure of the switch-on current limitation does not present a problem in reality in the case of direct-voltage supply.

Claims (7)

  1. CLAIMS: 1. A circuit arrangement for electronic ballasts for operating gas discharge lamps, wherein the circuit arrangement is connectable between a supply voltage source and an electronic harmonics filter of the electronic ballast for switch-on current limitation and for overvoltage protection of the electronic ballast, said circuit arrangement comprising: a field-effect transistor, the source-drain section of which is connected between a first output connection of the circuit arrangement and a first input connection of the circuit arrangement, wherein a second input connection is connected directly to a second output connection; a bipolar transistor, the base voltage of which is dependent on the supply voltage via a voltage divider; and a charging capacitor connected in parallel with the gate-source section of the field-effect transistor, and also connected to the collector-emitter section of the bipolar transistor such that the charging capacitor is charged if the bipolar transistor turns off and the base voltage of the bipolar transistor lies below a predetermined base voltage threshold value of the bipolar transistor, until the voltage of the charging capacitor exceeds a gate voltage threshold value of the field-effect transistor at which threshold voltage the field-effect transistor is turned on such that the first input connection of the circuit arrangement is connected to the first output connection thereof via the source-drain section of the field-effect transistor and the charging capacitor discharges and charges an input capacitor of the electronic harmonics filter, and wherein the field-effect transistor remains switched on until the base voltage at the bipolar transistor exceeds the threshold value thereof to turn on the bipolar transistor and thus short circuit the charging capacitor such that the gate voltage of the field-effect transistor falls below the threshold value thereof and the field-effect transistor is turned off until the base voltage dependent upon the input voltage falls below the base voltage threshold value of the bipolar transistor.
  2. 2. A circuit arrangement according to claim 1, wherein the voltage divider connected to the base of the bipolar transistor comprises a first resistance connected in parallel with the base-emitter section of the bipolar transistor, and having a first end connected to the first input connection of the circuit arrangement and second end connected, (a) via a first resistor circuit and a capacitor, and (b) via a second resistor circuit, to the second input connection, the second resistor circuit comprising a second resistance connected in parallel with the first resistance via a diode.
  3. 3. A circuit arrangement according to claim 2, wherein the first output connection of the circuit arrangement is connected via a further diode to the first resistor circuit and the second capacitor, the further diode reducing the voltage across the first resistor circuit and the first resistance if the field-effect transistor is switched on, such that the bipolar transistor is switched off until a voltage supplied to the base of the bipolar transistor via the second resistor circuit and the diode exceeds the base voltage threshold value of the bipolar transistor.
  4. 4. A circuit arrangement according to any one of the preceding claims, further comprising a heat-sensitive resistance connected in parallel with the source-drain section of the field-effect transistor as protection against voltage peaks.
  5. 5. A circuit arrangement according to any one of the preceding claims, wherein the charging capacitor is connected via a third resistor circuit to the collector and emitter of the bipolar transistor and via a fourth resistor circuit to the second input connection and the second output connection of the circuit arrangement.
  6. 6. A circuit arrangement according to any one of the preceding claims, wherein the circuit arrangement is connected in use to the electronic ballast such that operation of an inverter or rectifier of the electronic ballast is interrupted by means of a separate overvoltage cutout provided in the electronic ballast if the field-effect transistor turns off and the base voltage of the bipolar transistor exceeds the base voltage threshold value.
  7. 7. A circuit arrangement substantially as hereinbefore described with reference to the accompanying drawings.
GB9703332A 1996-02-19 1997-02-18 Circuit arrangement for current limitation and for overvoltage protection Expired - Fee Related GB2310328B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE29602914U DE29602914U1 (en) 1996-02-19 1996-02-19 Circuit arrangement for inrush current limitation and overvoltage protection for an active harmonic filter of an electronic ballast

Publications (3)

Publication Number Publication Date
GB9703332D0 GB9703332D0 (en) 1997-04-09
GB2310328A true GB2310328A (en) 1997-08-20
GB2310328B GB2310328B (en) 1999-10-06

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB9703332A Expired - Fee Related GB2310328B (en) 1996-02-19 1997-02-18 Circuit arrangement for current limitation and for overvoltage protection

Country Status (3)

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DE (1) DE29602914U1 (en)
GB (1) GB2310328B (en)
NL (1) NL1005221C2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3182572A1 (en) * 2015-12-17 2017-06-21 Grundfos Holding A/S Electronic circuit and method for operating an electronic circuit

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016011815B3 (en) * 2016-10-05 2018-02-15 IAD Gesellschaft für Informatik, Automatisierung und Datenverarbeitung mbH Control gear with staggered overvoltage and overcurrent protection for the control of intelligent light sources and devices as well as light sources with this control gear
CN106992501B (en) * 2017-04-19 2023-05-09 赛尔富电子有限公司 Direct-current power supply capable of preventing power supply from being connected by mistake in output and LED lamp and control system thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0423885A1 (en) * 1989-10-17 1991-04-24 Philips Patentverwaltung GmbH Current supply with inrush current limitation
EP0524425A1 (en) * 1991-06-26 1993-01-27 Siemens Aktiengesellschaft Circuit arrangement for limiting the inrush current and overvoltage protection for switching mode current supply devices
WO1995005696A2 (en) * 1993-08-12 1995-02-23 C.M. Personnel Participation B.V. Protection circuit for electronic systems in general and for an electronic ballast operating discharge lamps in particular

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4891728A (en) * 1986-12-23 1990-01-02 Siemens Aktiengesellschaft Circuit arrangement for limiting the switch-on current and for providing an over voltage protection in switch mode power supply devices
DE3801776C2 (en) * 1988-01-22 1995-11-23 Vdo Schindling Protection circuit for a load resistor (consumer) connected to the motor vehicle battery and its switching output stage
DE4013731C2 (en) * 1990-04-28 1995-07-13 Sel Alcatel Ag Circuit arrangement for limiting the inrush current
DE59508863D1 (en) * 1995-08-04 2000-12-21 Siemens Ag Electronic ballast with inrush current limitation and / or surge protection

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0423885A1 (en) * 1989-10-17 1991-04-24 Philips Patentverwaltung GmbH Current supply with inrush current limitation
EP0524425A1 (en) * 1991-06-26 1993-01-27 Siemens Aktiengesellschaft Circuit arrangement for limiting the inrush current and overvoltage protection for switching mode current supply devices
WO1995005696A2 (en) * 1993-08-12 1995-02-23 C.M. Personnel Participation B.V. Protection circuit for electronic systems in general and for an electronic ballast operating discharge lamps in particular

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3182572A1 (en) * 2015-12-17 2017-06-21 Grundfos Holding A/S Electronic circuit and method for operating an electronic circuit
CN106936302A (en) * 2015-12-17 2017-07-07 格兰富控股联合股份公司 Electronic circuit and the method for operating electronic circuit
CN106936302B (en) * 2015-12-17 2019-06-18 格兰富控股联合股份公司 Electronic circuit and method for operating electronic circuit
US10468969B2 (en) 2015-12-17 2019-11-05 Grundfos Holding A/S Electronic circuit and method for operating an electronic circuit

Also Published As

Publication number Publication date
NL1005221C2 (en) 2000-02-15
GB9703332D0 (en) 1997-04-09
GB2310328B (en) 1999-10-06
NL1005221A1 (en) 1997-08-20
DE29602914U1 (en) 1997-06-19

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20150218