Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
  • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
  • H03K17/60—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors
  • H03K17/601—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being bipolar transistors using transformer coupling

Definitions

• This invention relates to a circuit for electronically switching of electronic components, electrical compo ⁇ nents or electromechanical components by means of a semiconductor, as can be used in for instance mains switches.
• the circuit for switching of electronic, electrical or electromechanical components by means of semiconductors according to the invention is characte ⁇ rised by energy transfer from the switching component to the switched component by an energy transferring component, that completely isolates the switching component from the switched component.
• the energy transferring component is a transformer.
• circuit according to the invention is provided with means in the primary circuit, by which the maximum energy trans ⁇ fer is limited, in such a way that the switching cir- cuit is protected in case of short circuit in the switching component.
• the means for limiting the maximum energy transfer in the primary circuit consist of a series resistor.
• the switching component In the normal condition, when the electronic, elec ⁇ trical or electromechanical component is to be swit ⁇ ched, the switching component, a semiconductor, passes an alternating current through the primary winding of a transformer, which at its turn generates an alternating current voltage in the depoty winding. This voltage, whether or not rectified, actuates the electronical, electrical or electromechanical component. In the case of short-circuiting or interruption of the switching component a direct current or no current respectively will flow through the primary winding. In both cases there will be no voltage generated in the depoty winding and the switched component can not be excited in any way. According to an embodiment of the present invention a series resistor in the primary circuit limits the maximum energy transfer, so that the switching circuit is protected in case of short circuiting of the swit- ching component, the semiconductor.
• defects in possible peripheral electronic, electrical or electromechanical components can not in any way lead to excitation of the switched component.
• the configuration according to the invention guaranties that the electronic, electrical or electromechanical components, for instance a relay, can not be excited in any way by whatever possible defect in the switching component.
• the invention will now be further described with refe- rence to a drawing of an example of an embodiment of the invention.
• the figure relates to a diagram of a circuit for electronically switching of a relay by means of a semiconductor, as can be applied in for instance a mains switch.
• the switching component 2 in this embodiment a transistor 2, is incorporated in the circuit 1.
• the resistor 2 When at input 3 an alternating current voltage, with well chosen suitable characteristics, is applied, the resistor 2 will pass an alternating cur- rent to the primary winding 4 of the voltage trans ⁇ ferring component 5, in this example of an embodiment the transformer 5.
• a suitable choice of the transfor ⁇ mer, which will lead to a high energy-efficiency of the switching circuit is for instance a close coupled transformer in the 10 KHz range.
• the transformer has in that case a transfer ratio of 1:1 and low core losse which guarantees an efficient energy-transfer. In view of the low voltages no high demands are made upon the insulation between the primary and the propel- ding of the transformer. In this case a lOKHz.
• the relay 8 which consists of an armature with two contacts 9 en 10 and an excitation coil 11, is arranged as a locking relay; when during a short period a signal in the form of the above-mentio ⁇ ned alternating current voltage is offered to the transistor 2, the relay 8 will be excited and will keep itself excited untill the connection between the protective contact breakers 12 and 13 is interrupted. It is possible to incorporate a contact breaker as off- switch at this place in the switching circuit. In this embodiment the switching circuit is active only for a very short period, that is only for the moment of swit- ching. In this embodiment the series resistor 14 in the primary circuit limits the maximum direct current in the primary circuit, in the event of short circuiting of the transistor 2.
• a resis ⁇ tor 15 and a pair of capacitors 16, 17 are shown.
• Through conducting path 18 flows a direct current.
• Through conducting path 19 a signal can be given in the form of an alternating current voltage, with characte ⁇ ristics, that enable the current to allow the transis ⁇ tor 2 and the transformer 5 to perform their respective functions.
• the conducting path 20 is mass.
• the energy reguired for the switched component of the invention is gene ⁇ rated by a converter or generator circuit.
• a converter or generator circuit There are many variations on this embodiment conceivable, which all remain within the scope of the invention; it is possible to use for the energy-generation a full bridge converter, a half bridge converter, an isolated forward converter, an isolated flyback converter, a non-isol ⁇ ated step up converter, a non-isolated step down con ⁇ verter etc.
• the various parts of the switching circuit can be integrated. More in particular it is possible to integrate the resistor 14 in the transformer 5, that functions as voltage transferring component, by choosing a suitable ohmic resistance for the primary winding 4. Furthermore an embodiment is conceivable in which the transformer 5, the eventual rectifier 7 and t .. relay 8 are integra ⁇ ted.
• the switching circuit can be combined with a piezo-electric element, that at a touch gives a voltage pulse. This voltage pulse serves as a signal for the excitation of the switching circuit.
• the switching circuit is provided with a micro-controller, in which the voltage pulse is offered to the micro-controller.
• the micro ⁇ controller is provided with software.
• the microcontrol ⁇ ler processes the offered signals and at its turn controls on the basis of the software stored in the microcontroller the circuit for switching the electro ⁇ nic, electrical or electromechanical components by means of semiconductors, by offering a signal to the ⁇ witching component in the form of a current, that is suitable to enable the switching component and the voltage transferring component to conduct their respec ⁇ tive functions.
• the configu- ration of the switching circuit with a piezo-electric element and a microcontroller as described above is provided with a variable current limiting device and current control system.
• variable current limiting device and the current control system are connected with the microcon ⁇ troller in a favourable manner, it is possible to let the microcontroller process the information from the variable current limiting device and the current con- trolsystem. By doing so, it becomes possible to make the microcontroller switch off the current on the basis of pre-chosen criteria when exceeding pre-determined values.
• variable current limiting device and the current control system consist of a specially designed transformer, that consists of a few or even one turn.
• the wire thickness is selected such, that it is sufficient for the current that is to be measured. In this way the voltage drop over the primary winding is very small.
• the depoty winding is designed such, that the startery voltage is directly proportional with the current through the primary winding. In this way the voltage on the secun ⁇ dary winding is a direct indication for the current in the primary winding.
• the depoty voltage measured in this manner is compared with an adjustable reference voltage. In summary four conditions are possible: no current, overload, short circuit and normal current.
• the current is rated by operating certain pre-chosen margins for the exceeding of the reference voltage at the comparison of the propely voltage with the refe ⁇ rence voltage.
• a status indication system for example in the form of a display with led'3, is connec ⁇ ted to the microcontroller, so that --.t is possible to survey the status of the system.
• the configu- ration of the switching circuit with a piezo-electric element, a microcontroller, a variable current limiting device and current controlsystem and a status indicati ⁇ on system described above is incorpor' ed in an her ⁇ metically sealp' J , environment resistant housing.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Electronic Switches (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=19863939

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Cited By (5)

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• 1994
  • 1994-03-14 NL NL9400394A patent/NL9400394A/nl unknown
• 1995
  • 1995-03-09 EP EP95910016A patent/EP0754369A1/en not_active Withdrawn
  • 1995-03-09 AU AU18256/95A patent/AU1825695A/en not_active Abandoned
  • 1995-03-09 WO PCT/NL1995/000089 patent/WO1995025384A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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