NL1038158C2 - METHOD AND DEVICE FOR STARTING A MICROPROCESSOR IN GENERAL AND A MICROCONTROLLER, MICROCOMPUTER OR OSCILLATOR IN PARTICULAR. - Google Patents

Description

Method and device for starting up a microprocessor in general and a microcontroller, microcomputer or oscillator in particular

The present invention relates to a method and device for the start-up of a microprocessor in general and a microcontroller and / or microcomputer and / or oscillator in particular characterized by at least an alternating voltage-supplying first supply source, at least first rectifying means for the supply by the first supply source to supply the alternating voltage supplied at least one first active component from the group of DIACs, thyristors, TRIACs, UJTs which is actively connected to the rectified alternating voltage, at least one electronic component which is connected to the first active component 10 and which triggers and switches on the first active component at least one first capacitor operatively connected to the active component which is charged during the period that the active component is switched on, at least second rectifying means connected in series with the first rectifying means and at least one second capacitor which is operatively connected to the second rectifying means, a first load that is at least operatively connected to the first capacitor and a second load that is at least operatively connected to the second capacitor with the time-average voltage across the first capacitor being at least 10% lower than the time-average voltage across the second capacitor and wherein the first load consists at least of a microprocessor and / or a microcontroller and / or a microcomputer and / or an oscillator. Furthermore, the present invention is characterized by at least one switching power supply consisting of at least the first load and which is started up at least initially and supplied with energy by at least some electrical energy from the first capacitor. Finally, the present invention is characterized by a isolating transformer in the switching power supply which is equipped with an additional secondary winding and which, after starting up the switching power supply with some energy from the first capacitor, takes over the power supply of the first load. This makes the technology according to the present invention extremely suitable for use in equipment for treating electrically conductive fluids such as water.

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preface

In electrical engineering there is often a need to have a high voltage and a stabilized low voltage at the same time. This need arises from the fact that a large number of ICs, including but not limited to microcontrollers, must be supplied with a low voltage of 5 Volts. However, it is undesirable to realize the 5 Volt facility by using a 50 Hz transformer since it has a relatively high cost price and takes up relatively much space on a 1038158 2 PCB. The use of two resistors as a voltage bridge to obtain a DC voltage of 5 volts in this way is not acceptable because of the large amount of electrical energy that is converted into heat in the largest resistor of the voltage divider. Since the 50 Hz transformer used according to the prior art for supplying ICs, including microcontrollers, also serves as a separation transformer between the mains and the low-voltage supply of the IC and / or the microcontroller, the omission of the 50 Hz low-voltage transformer according to state of the art is not obvious. In case the power supply of the microcontroller and / or ICs is not galvanically isolated from the public electricity grid, it is necessary to keep the high voltage power supply galvanically isolated from the microcontroller and / or the ICs. Such a galvanic separation of a high-voltage power supply is particularly important if the power supply is used in an environment where conductive liquids such as water are present. This means that electrical power supplies for treating and / or disinfecting water must meet very high safety requirements.

The present invention relates to a new type of electronic circuit with which it is possible to efficiently obtain a galvanically separated high voltage from the public electricity network, a first low voltage and a second low voltage. With the technology according to the present invention it is considerably cheaper to control ICs, including microcontrollers, via the public electricity network than is possible according to the prior art. In addition, it is possible with the technology according to the present invention to realize switching power supplies reliably, safely and at a low cost. An important advantage of switching power supplies according to the technique of the present invention over prior art is that the switching power supplies according to the technique of the present invention switch off automatically if the switching power supply is overloaded. Furthermore, switching power supplies according to the technology of the present invention do not require a feedback loop.

The switching power supplies according to the technology of the present invention are generally usable and particularly suitable as a building block for equipment for treatment and / or disinfection of water.

Description of the technology according to the present invention

According to a first aspect, the technology according to the present invention consists of an alternating voltage supply first supply source. This power source can be a generator, the public electricity grid or any other alternating voltage source.

According to a second aspect, the present invention consists of at least rectifying means for rectifying the alternating voltage supplied by the first supply source.

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The rectifying means preferably consist of a diode bridge or a single diode or a vacuum tube with diode function.

According to a third aspect, the technology according to the present invention consists of at least one first active component operatively connected to the rectified alternating voltage from the group of DIACs, thyristors, TRIACs, UJTs. The first active component has the function of effectively connecting rectified alternating current only at set times with the first capacitor and / or the first load. The first active component thus serves as a switch and ensures, by means of an adjustable duty cycle, charging of the first capacitor and / or providing the first load with electrical energy. In short, it has great advantages to only effectively connect the first capacitor to the rectified alternating voltage for short time intervals. The length of the time intervals in which the first capacitor is operatively connected to the alternating direct voltage are chosen so short that just enough electrical energy is transported to the capacitor and / or the first load for the first load to function properly. This method has the advantage that it is possible to supply a first load with a time-averaged DC voltage that is considerably lower than the time-averaged DC voltage from the rectified alternating voltage supplied by the first supply source and the rectifying means operatively connected thereto, without this is accompanied by high heat development in a power resistor connected in series with the first load.

In a fourth aspect, the technology according to the present invention consists of means for switching on and off the first active component from the group of DIACs, thyristors, TRIACs, UJTs during the desired time intervals so that a duty cycle is obtained with which the first capacitor with a high electrical efficiency is charged and / or the first load is supplied with electrical energy. Such means preferably consist of a series connection of a resistor and a capacitor or of a trigger circuit which is built around a microprocessor and / or microcontroller and / or computer and / or oscillator. The use of a microcontroller is herein preferable to the other trigger circuits since with a microcontroller the duty cycle and thus the energy efficiency and heat development can be set by software.

According to a fifth aspect, the technology according to the present invention consists of second rectifying means, preferably at least one diode, connected in series with the first rectifying means and at least a second capacitor which is operatively connected to the second rectifying means and at least a second load at least operatively connected to the second capacitor wherein the time-averaged 4 voltage across the first capacitor is at least 10% lower than the time-averaged voltage across the second capacitor. It is clear to the skilled person that by using the second rectifying means the second capacitor has no flattening properties for the alternating direct voltage encountered by the first active components from the group of DIACs, thyristors, TRIACs, UJTs. This makes it possible to trigger the first active components with the aid of the alternating direct voltage and to adjust the duty cycle with which the alternating direct voltage is effectively connected to the first capacitor to a desired value.

According to a sixth aspect, the technology according to the present invention consists of means for protecting the first capacitor against too high a voltage, i.e., against a voltage that is higher than the maximum voltage for which the first capacitor is designed. A non-limiting example of means for protecting the first capacitor from a voltage higher than this maximum voltage for which the first capacitor is designed is a zener diode that is connected in parallel with the first capacitor.

According to a seventh aspect, the technology according to the present invention consists of at least one switching power supply consisting of at least the first load and which is started up at least initially and supplied with energy by at least some electrical energy from the first capacitor. As previously noted, the first load in the switching power supply is preferably a microprocessor and / or a microcontroller and / or a computer and / or an oscillator. Even more preferably, the first load is applied to start the switching power supply, i.e., to control the switching active components of the switching power supply, which are usually power FETs. Most preferably, the first load drives FETs which are connected in the configuration of a push pull amplifier and which alternately connect one half of the primary coil of a transformer, later called the first switching power supply transformer, to a direct current source. The secondary coil of the capacitor therefore supplies an alternating voltage. The frequency of the alternating voltage supplied by the secondary coil of the transformer is determined by the frequency with which the first load drives the power FETs. According to an eighth aspect, the technology according to the present invention consists of means for supplying the first load, i.e. the control of the switching power supply, with electrical energy as soon as the first load has started the switching power supply. In short, in this case the first load causes the switching power supply to operate, after which part of the electrical energy produced by the switching power supply is used to take over the driving task of the first load. The means for supplying the first load, i.e. the control of the switching power supply, with electrical energy as soon as the first load has started the switching power supply are referred to below as permanent control means. The permanent control means 5 preferably originate from an additional secondary coil which forms part of the first switching power supply transformer. This extra secondary coil has just as many turns as necessary to deliver the voltage at which the first load functions. This makes the control very efficient. Preferably, the alternating voltage supplied by the secondary coil is rectified by a diode and / or diode bridge 10 and smoothed by a third capacitor. Even more preferably, a diode is connected between the third capacitor and the first load. In addition, a diode is most preferably also connected between the first capacitor and the first load. This ensures that the means for starting up the power supply and the permanent control means do not adversely affect each other. It is clear to the person skilled in the art that through smart switching of diodes it is also possible to replace the first and the third capacitor by a single capacitor.

According to a ninth aspect, the technology according to the present invention consists of a protection that protects the switching power supply against overload.

This protection consists of at least one and preferably more than one of the following protection elements: • A first switching power supply transformer designed in such a way that the voltage of the additional secondary coil, which supplies the voltage on which the permanent control means operate, collapses when the first switching power supply transformer being overloaded. The result is that the microprocessor and / or microcontroller and / or oscillator is no longer supplied with sufficient electrical energy to control the switching power supply. This causes the switching power supply to fail. Parameters for designing the first switching power supply transformer such that the voltage of the secondary coils collapse in the event of overload are: gap size in the applied ferrite core, saturation of the core, applied frequency and duty cycle with which the first switching power supply transformer is controlled, number of turns of primary coil and the secondary coil on the transformer.

A current coil in series with the primary winding of the first switching power supply transformer, preferably followed by a rectifier and a capacitor to obtain a smoothed DC voltage which is a measure of the current flowing through the primary winding of the first switching power supply transformer, an analog-to-digital converter which is preferably operatively connected to a microprocessor and / or a microcontroller and / or a computer or which forms part of a microprocessor and / or microcontroller and / or a computer, software that supplies it to the analog-to-digital converter automatically interpret the signal and adjust the duty cycle of the signal produced by the set of permanent control means and the first load such that the maximum acceptable time-averaged current is not exceeded.

A current coil in series with a secondary winding of the first switching power supply transformer, preferably followed by a rectifier and a capacitor to obtain a smoothed DC voltage which is a measure of the current flowing through the relevant secondary winding of the first switching power supply transformer , an analog-to-digital converter that is preferably operatively connected to a microprocessor and / or a microcontroller and / or a computer or that forms part of a microprocessor and / or microcontroller and / or a computer, software that connects it to the analog-to-digital converter signal applied automatically and adjusts the duty cycle of the signal produced by the set of permanent control means and the first load such that the maximum acceptable time-averaged current is not exceeded.

· A fuse in any electrical circuit of the switching power supply or in the circuit of any load connected to the switching power supply whereby this fuse is accelerated by a SCR (silicon controlled) in case of a short circuit or a determined too high current rectifier such as a thyristor or triac). In short, this accelerated-blown fuse functions as follows: if a protection circuit detects too high a current and / or short-circuit, the SCR, which is preferably operatively connected to the plus and minus of the power supply, is activated. The consequence of this is that a very large current flows through the SCR for a short time. The fuse provided in the protection circuit is positioned such that the current through the SCR also passes through this fuse. The consequence of this is that the fuse blows very quickly as soon as the SCR is activated.

Now that the characteristics of the technology according to the present invention have been set out, 2 examples follow that further explain the technology according to the present invention.

It is noted that the technology according to the present invention has numerous embodiments and that the examples are cited as non-limiting examples for further explanation of the technology according to the present invention.

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Example 1

In this example, the circuit in Figure 1 serves to further explain the technology according to the present invention. An alternating voltage is rectified with diode bridge DB. This results in a varying direct voltage which, as is clearly visible in Figure 1, is not smoothed by means of a capacitor. This alternating direct voltage is effectively connected via resistor R2 to zener diode D2. Transistor T1 is driven by a current through R3 and R2 as long as the voltage across control transistor TR is smaller than the voltage across zener diode D2. As a result, the thyristor D1 is conducting during this period. As soon as the voltage across the control transistor TR threatens to become larger than the voltage across the zener diode, transistor T1 is cut off with the result that the thyristor D1 is cut off and capacitor C1 is no longer charged. The net result is that the time-average voltage drop across transistor TR is approximately equal to the voltage across zener diode D2. By controlling the voltage at point P by using a voltage controller, for example a circuit based on a controller of the type LM317 or by using a voltage controller that is controlled by means of a microcontroller and / or microprocessor, the voltage at point A can be accurately set. An essential advantage that application of the circuit in Figure 1 entails over other circuits is that the low voltage at point A is obtained without using a load resistor. In fact, the low voltage is set by automatically creating the correct duty cycle with which thyristor D1 conducts to charge capacitor C1. Since hardly any electrical energy is dissipated in heat when D1 is switched off, the circuit in Figure 1 is an efficient solution for obtaining a lower flattened direct voltage from a high alternating direct voltage. The example in Figure 1 is one of the many possible configurations with which a stabilized low voltage can be obtained from a high alternating direct voltage. The technology according to the present invention involves feeding a microprocessor and / or a microcontroller and / or an oscillator by connecting it to the low voltage obtained from a high alternating direct voltage. In the non-limiting example in figure 1, the microprocessor and / or microcontroller and / or oscillator is connected to point A. If desired, the microprocessor and / or microcontroller and / or oscillator is not directly connected to point A, but use is made of a second low voltage stabilizer which further lowers the low voltage at point A to a voltage on which the microprocessor and / or microcontroller and / or oscillator operates, such as, for example, a voltage of 5.0 Volts in the case that the microcontroller is of the PIC16F88 type. Namely, it can be particularly advantageous to set the voltage in point A to a value that is higher than 5.0 Volts. For the voltage in point A, a value of 8 approximately 24 Volts (between 10 Volts and 30 Volts) is preferably chosen. By subsequently lowering this voltage to 5 Volt by using a second voltage regulator, 2 low voltages are obtained. The first and lowest low voltage can be used to control a microprocessor and / or microcontroller while the second and less low low voltage can be used to power a transistor and / or FET that is driven by the microprocessor and / or microcontroller of electrical energy. to provide. The microprocessor and / or microcontroller preferably drives the transistor and / or FET directly or in series with a resistor on the base and / or the gate. The second less low low voltage is operatively connected to optionally a resistor, the collector and emitter of a transistor and / or optionally a resistor, the drain and the source of a FET. In this way, thanks to the use of the transistor and / or FET, a control is obtained for a relay and / or a power transistor and / or a power FET. It is known to the person skilled in the art that direct control of a relay, a power transistor and / or a power FET by the microcontroller and / or the microprocessor is often not possible since the current which can be an I / O output of a microcontroller and / or microprocessor supply is limited as well as the voltage that a microcontroller and / or microprocessor can supply. It is also known to those skilled in the art that a power FET is preferably driven with a voltage higher than 5 volts, i.e. with a voltage that is preferably between 8 volts and 20 volts.

According to the technology of the present invention, the microcontroller and / or microprocessor is used to control a switching power supply. For this purpose the microcontroller and / or microprocessor alternately switches 2 NPN transistors on and off by connecting the base of the transistors to the output of the microcontroller and / or microprocessor. The emitter of the transistors is connected to the ground and the collectors to the plus of the second and less low low voltage through collector resistors. By effectively connecting each of the collectors of the NPN transistors directly or by means of a capacitor and / or resistor and / or voltage divider to a power transistor or a power FET, these power transistors or power FETs can be controlled by software via the microcontroller. In short, the FETs or power transistors of the power amplifier are alternately switched on and off via the software in the microcontroller and / or microprocessor. By now effectively connecting the FETs or power transistors to a transformer with center tap by effectively connecting the center tap to the plus of the rectified and possibly flattened high voltage and connecting the FETs or power transistors each with a coil end and the ground, a software programmable Switching power supply according to the push pull principle. The 9 transformer with center tap is preferably a transformer with a ferrite core suitable for frequencies in the range of 1 kHz to 1 GHz. Even more preferably, the ferrite core transformer is suitable for frequencies in the range of 20 kHz to 100 kHz. According to the technology of the present invention, a secondary coil 5 is used to provide a power load with electrical energy. At least a second secondary coil, which is galvanically isolated from all other coils on the transformer, is used if desired to take over the function of the start-up circuit as soon as the switching power supply operates.

Example 2 In this example the circuit in figure 2 serves to further explain the technology according to the present invention. An alternating voltage is rectified with diode bridge DB. This results in a varying direct voltage which, as is clearly visible in Figure 2, is initially not flattened by means of a capacitor. Thyristor D1 is operatively connected to the alternating direct voltage and the gate of the thyristor is operatively connected to a series connection of at least one resistor R1 and a capacitor C1. The cathode of the thyristor is operatively connected to resistor R2, zener diode D2 and buffer capacitor C2. The operation of the circuit in Figure 2 is as follows:

Capacitors R1 and C1 are charged by the alternating DC voltage. As soon as the voltage across capacitor C1 exceeds a limit value, thyristor D1 starts to conduct. The thyristor then remains conductive until the varying direct voltage across the cathode and anode of D1 falls below the limit value at which D1 can remain conductive. From that moment on, the thyristor turns off until the moment that capacitor C1 is sufficiently charged again to ignite the thyristor again. Important aspects of the circuit are that the R1 and C1 ensure that there is a phase difference between the alternating direct voltage and the trigger voltage of the gate of the thyristor. It is clear to a person skilled in the art that thanks to this phase difference the duty cycle with which the circuit buffer capacitor C2 charges can be accurately set. Diode D3 in Fig. 2 has the function of creating a situation where on the one hand there is an alternating direct voltage on the anode side of diode D3 which is necessary for the thyristor to function properly and on the other hand a situation on the cathode side of diode D3. creating a smoothed high voltage by means of capacitor C3. Example 2, likewise as example 1, clearly demonstrates that it is possible to realize a circuit which converts a high DC voltage, whether or not alternating, without large energy loss into a stabilized low voltage.

Examples 1 and 2 can be used as a continuous energy source for a load that operates on a low voltage, this low voltage being generated from a much higher direct voltage or alternating direct voltage. Such an application is extremely suitable for energizing microcontrollers and / or microprocessors and / or oscillators which are used in switching power supplies as driving components. Such an application is expressly part of the present invention.

More preferably, the technology according to the present invention is generally used, and as described in examples 1 and 2 in particular, to start up switching power supplies equipped with at least one isolating transformer, after which a secondary winding of the isolating transformer then functions of the boot process. This configuration not only leads to an even higher energy efficiency of the circuit and thus less heat development, but also to an even greater safety of the circuit. It is noted that the active components in Fig. 1 and Fig. 2 of the start-up circuit can, if desired, be switched off by means of software and an output of the microcontroller and / or microprocessor, so that the start-up circuit is switched off continuously. As a non-limiting example, placing the gate of thyristor D1 in the ground in Figure 2 is mentioned.

The switching power supply with isolation transformer, start-up and protection as described in this application is extremely suitable for energizing electronic control of equipment for the treatment of water or water-containing media.

Non-limiting examples of such equipment are UV disinfection reactors, electrolysis reactors, AC disinfection reactors, AC over DC disinfection reactors, ultrasonic disinfection reactors, ozone generators, electromagnetic transmitters for disinfecting water. These applications are explicitly part of the present invention. These applications require power supplies that are galvanically isolated from the mains and contain a number of protections to prevent water from being energized. At the same time, these applications require compact power supplies. Finally, these applications require that the switching power supply in terms of functionality can be software-matched to the properties of the water to be treated or the water-containing medium. The technology according to the present invention meets all these requirements.

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Claims (11)

1. Switching power supply characterized by • at least one alternating voltage supplying first supply source, • at least first rectifying means for rectifying the alternating voltage supplied by the first supply source, • at least one first active component from the group of DIACs which is operatively connected to the rectified alternating voltage, thyristors, TRIACs, UJTs, • at least one electronic component or group of electronic components that can be connected to the first active component and which triggers and switches on the first active component, • at least one first capacitor which is connected to the active component and which during the period that the active component is switched on is charged • at least second rectifying means which are connected in series with the first rectifying means and • at least a second capacitor which is operatively connected to the second rectifying means, • at least a first b a load that is at least operatively connected to the first capacitor and 20. a second load that is at least operatively connected to the second capacitor wherein • the time-averaged voltage across the first capacitor is at least 10% lower than the time-averaged voltage across the second capacitor and • wherein the first load consists of at least a microprocessor and / or a microcontroller and / or a microcomputer and / or an oscillator, characterized in that • this microprocessor and / or microcontroller and / or microcomputer and / or oscillator directly controls the power stage of the switching power supply or indirectly controls 30. a disconnecting transformer characterized by • at least a first secondary coil that is galvanically isolated from all other coils on the transformer and that is operatively connected to a load 2. Device as claimed in claim 1 plus at least a second secondary coil on the isolation transformer, said second secondary coil providing at least some electrical energy to the microprocessor and / or microcontroller and / or microcomputer and / or 1038158 oscillator after the switching power supply has been started. 3. Device as claimed in any of the foregoing claims 1 and 2, wherein the microprocessor and / or microcontroller and / or microcomputer switches off the first active component and therewith the start-up circuit with software after the switching power supply has been started. Device as claimed in any of the foregoing claims 1 to 3 plus an overload protection of the switching power supply characterized by at least one of the following protection means: • A switching power supply transformer, characterized in that the voltage of the additional secondary coil which supplies the voltage at which the permanent control means, as defined in the description, operate when the first switching power supply transformer is overloaded, with the result that the microprocessor and / or microcontroller and / or oscillator are no longer supplied with sufficient electrical energy to 15 to control the switching power supply, causing the switching power supply to fail. A current coil in series with the primary winding of the switching power supply transformer, followed by a rectifier and a capacitor to obtain a smoothed DC voltage that is a measure of the current flowing through the primary winding of the first switching power supply transformer, an analog to digital converter that is operatively connected to a microprocessor and / or a microcontroller and / or a computer or that forms part of a microprocessor and / or microcontroller and / or a computer, software that automatically interprets the signal applied to the analogue to digital converter and the adjusts the duty cycle of the signal produced by the set of permanent drive means and the first load such that the maximum acceptable time-averaged current is not exceeded. A current coil in series with a secondary winding of the switching power supply transformer, preferably followed by a rectifier and a capacitor to obtain a smoothed DC voltage that is a measure of the current flowing through the relevant secondary winding of the first switching power supply transformer, an analog-to-digital converter that is preferably operatively connected to a microprocessor and / or a microcontroller and / or a computer or that forms part of a microprocessor and / or microcontroller and / or a computer, software that supplies it to the analog-to-digital converter automatically interpret the signal and adjust the duty cycle of the signal produced by the set of permanent drivers and the first load so that the maximum acceptable time-averaged current is not exceeded. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as control of a UVC reactor for treatment and / or disinfection of water or media consisting of at least 10% water. 5. A fuse in any electrical circuit of the switching power supply or in the circuit of any load connected to the switching power supply whereby this fuse is accelerated by a SCR (silicon controlled) in case of a short circuit or a determined too high current rectifier such as a thyristor or triac). 6. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as control of an electrolysis reactor for treatment and / or disinfection of water or media consisting of at least 10% water. 7. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as control of an ozone reactor for treatment and / or disinfection of water or media consisting of at least 10% water. 8. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as control of an ultrasonic reactor for treatment and / or disinfection of water or media consisting of at least 10% water. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as control of an AC over DC electrolysis reactor for treatment and / or disinfection of water or media consisting of at least 10% water. Device as claimed in any of the foregoing claims 1-4, wherein the switching power supply is used as a control for an electromagnetic transmitter for treatment and / or disinfection of water or media consisting of at least 10% water. 11. Method for a switching power supply characterized by a device as defined in one of the preceding claims 1 to 10. 1 0 3 8 1 5 8