DE1613445C

DE1613445C - Circuit arrangement for overload and short-circuit protection of a DC voltage converter

Info

Publication number: DE1613445C
Authority: DE
Inventors: Fritz 7530 Pforzheim Walther
Original assignee: Standard Elektrik Lorenz AG
Current assignee: Alcatel Lucent Deutschland AG
Publication date: 1972-09-28

Description

Siebkette mit der Hauptwicklung 3 und dem Konden- abfäUe für den Steuerkreis ^.Tj^j⁰^!⁰*¹^Sieve chain with the main winding 3 and the condensate waste for the control circuit ^ .Tj ^ j ⁰ ^! ⁰ * ¹ ^

satorS aufgeladen, öffnet sich der Schalter^ dann Der Widerstand der Zusatzwicklung4 ist fconer oe-satorS charged, the switch opens ^ then the resistance of the additional winding4 is fconer oe-

entlädt sich die Siebkette 3/5 über den Lastwider- messen als der der Hauptwicklung 3. WWt ememthe sieve chain 3/5 discharges itself over the load countermeasure than that of the main winding 3. WWt emem

stand 6, wobei eine Diode 10 die Verbindung zum Regelwiderstand 14 wird der Strom °urcn diesestood 6, whereby a diode 10 is the connection to the variable resistor 14, the current ° urcn this

Gegenpol (Masse) hersteUt Zur Stabilisierung der 5 Wickimg 4 so emgesteUt, daB der TraMBtorwnocnOpposite pole (mass) established To stabilize the 5 windings 4 so carefully that the traMBtorwnocn

Ausgangsspannung ist ein Transsistor 11 vorgesehen, gesperrt ist, wenn der *™™ttm&si&* ^ Output voltage is provided by a transistor 11, which is blocked when the * ™haben ttm & si & * ^

dessen Basis durch die Ausgangsspannung gesteuert durch die Hauptwicklung3 föeüt uaim ^whose base is controlled by the output voltage through the main winding3 föeüt uaim ^

wird. Sobald der durch eine Zenerdiode 12 gegebene Gleichspannungsabfälle an den beiden ™^ⁿ will. As soon as the DC voltage drop given by a Zener diode 12 at the two ™ ^ ⁿ

SchweUwer·. überschritten ist, wird der Transistor 11 nahezu gleich und deren ^Me?^** *^* ^r !eilend und beeinflußt den Modulator 8 derart daß to Damit dieser SchweUwert von der lcmperatur uerHeavy ·. is exceeded, the transistor 11 is almost the same and their ^Me? ^ ** * ^ * ^ r! haste, and influenced the modulator 8 so that to ensure that this SchweUwert from the lcmperatur uer

sich die Breite der an den Impulsformer 9 abge» Wicklungen unabhängig ist, J*f^ ""^"JJthe width of the windings on the pulse shaper 9 is independent, J * f ^ "" ^ "JJ

gebenen Impulse vermindert Ausgestaltung der Erfindung beide Wicklungen ausgiven pulses reduced embodiment of the invention from both windings

Während des normalen Betriebes wird demnach demselben Drahtmaterial oder aus M^naüen mitDuring normal operation, the same wire material or from M ^ naüen is therefore with

der Transistor H die Schaltzeiten des Schalters 2 bei gleichem Temperaturbeiwert fur die, wuursianas-the transistor H the switching times of the switch 2 with the same temperature coefficient for the wuursianas-

steigender Ausgangsspannimg verkürzen. Bei Über- 15 änderung. Ferner sind nach «°" *■**"^ Γ Λ Shorten increasing output voltage. In the event of a change. Furthermore, after «°" * ■ ** "^ Γ Λ

last und im KurzschlußfaU, wenn der SchweUwert stellung der Erfindung beide Wicklungen auch tnerload and in the short-circuit case, if the SchweUwert position of the invention both windings also tner

der Zenerdiode 12 unterschritten ist, ist der Tran- misch miteinander gekoppelt ηκ-ι«.the Zener diode 12 is undershot, the tran- mix is coupled to one another ηκ-ι «.

sistor 11 unwirksam, und es stellt sich die maximale Liegt der Laststrom unter dem zulässigen nocnst-sistor 11 ineffective, and the maximum is the load current is below the permissible next-

Breite der Schaltimpulse ein. Das führt zur Zer- wert, so überwiegt der Spannungsabfall »na«Width of the switching impulses. This leads to the decomposition, so the voltage drop predominates »na«

störung des Transistors 2, der nicht in der Lage ist, ao Zusatzwicklung 4, und dt. Transistor LJ ist £*P«?·Disturbance of transistor 2, which is not able to ao additional winding 4, and German transistor LJ is £ * P «? ·

den Überstrom über lange Zeit au-uhalten. Es ist Wird der Höchstwert üben-chntten oder mn emMaintain the overcurrent for a long time. It is Will the maximum value practiced or mn em

deshalb eine Anordnung notwendig, die vom Last- Kurzschluß ein, dann überwiegt der bpannun saDiaiitherefore an arrangement is necessary, from the load short-circuit, then the bpannun saDiaii predominates

strom beeinflußt die Schaltzeiten des Transistors 2 an der Hauptwicklung 3 und der J"°»«°'" ^W1™current influences the switching times of transistor 2 on main winding 3 and J "°» «° '" ^W1 ™

herabsetzt wenn ein vorgegebener Höchstwert der leitend. Dieser steuert den ^piilsformer y aeran,reduces the conductive value when a specified maximum value. This controls the piilsformer y aeran,

Belastung Überschritten ist. a₅ daß die Impulsdauer so weit verkürzt wird oder dessenLoad has been exceeded. a ₅ that the pulse duration is shortened so much or its

Hierzu erhält die Siebdrossel außer der Haupt- Impulse den Schalter 2 so lange nicht errocjen1 ms wicklung 3 eins Zusatzwicklung 4 mit gleicher Win- der Strom durch die Wicklung 3 den unzulässigen dungszahl. Die Anfänge dieser beiden Wicklungen Wert unterschritten hat und der Iransistor υ wicucr sind miteinander verbunden, und an den Enden der- gesperrt ist. Die Schallgeschwindigkeit des 1 ranselben liegt die Basis-Emitter-Strecke eines Tran- 30 sistors 13 ist im wesentlichen durch die ZeitKonstame sistors 13. Auf diese Weise ist der Gleichsuannungs- bestimmt, welche die mit dem sehr niedrigen Lastabfall an der vom Laststrom durchflossenen Haupt- widerstand 6 abgeschlossene Siebkette im uoerwicklung 3 an deir Tiansistor 13 wirksam, wobei die lastungsfaU aufweist. Jedenfalls ist dies&cnj"-Zusatzwicklung4 eine Kompensation der Rest- geschwindigkeit se»kurz, daß k«^nft ^^retrome J™ welligkeit und, z.B. durch kurzzeitige Überströme 35 Stromflußzeiien durch den Schalter2 entstenen hervorgerufener, sonstiger induktiver Spannungs- können, die zu dessen Zerstörung runren.For this purpose, in addition to the main impulse, the filter choke receives switch 2 as long as it does not errocjen1 ms winding 3 one additional winding 4 with the same winding current through winding 3 has the impermissible number of connections. The beginnings of these two windings has fallen below the value and the Iransistor υ wicucr are connected to one another, and at the ends of the- is blocked. The speed of sound of the 1 is the same as the base-emitter path of a transistor 13 is essentially determined by the time constant 13. In this way, the DC voltage is determined, which is the very low load drop on the main circuit through which the load current flows. Resistance 6 completed sieve chain in the winding 3 on deir Tiansistor 13 effective, with the load being shown. Anyway, this is & cnj "-Zusatzwicklung4 a compensation of the residual speed se" short that k ^"nft ^ ^retrome J ™ ripple and such entstenen by brief streams 35 Stromflußzeiien by the switch2 induced, other inductive voltage can that runren to its destruction .

Hierzu 1 Blatt Zeichnungen1 sheet of drawings

Claims

ι 2 plates and the connection point of the first counter-claims: state and the load connected in this way and the collector-emitter path of this transistor with ücm

1. Circuitry for the overload and control circuit of the converter is connected in such a way that Short-circuit protection of a DC voltage 5 the transistor in the conductive state eme limitation converter 'caused by a filter choke in the load current of the load current, with the partial behavior circuit, in which a first of the voltage divider in series with the load is dimensioned so that the Tim. Resistance is connected, between which of sistor is just blocked when aen im the connection facing away from the load and the resistance lying against the load circuit an io permissible load current flows with this resistor.

Closing the load a voltage divider from two Such a circuit arrangement is known

Resistors is connected, in addition (Belgian patent specification 621277). In the known, the base-emitter path of a transistor to DC voltage converter is used to switch a switching transistor located in the tap of the voltage divider and the connecting load current path em connection point of the first resistor and the load 15 pulse generator, in which the Ruckkoppderart is connected and the collector lung emitter and the extraction of the switching voltage by means of path of this transistor with dtm control circuit of a transformer erfolgt- this transformer has the converter is connected such that inter alia a further winding on, η to which the transistor 1 conducting state, the ratio collector-emitter -Distance of the mentioned, the Stromder Stromflusszeiten to the blocking times of the ao limiting causing transistor via ice ..- converter is reduced, with the partial ratio diode is connected. The transmission winding η of the voltage divider is dimensioned in such a way that the and this diode are polarized in such a way that after the transistor is just blocked, if the maximum permissible load current flows by exceeding the rated load current, the blocking time of the switching transistor located in the resistance of the load current path in the load circuit increases, thereby becomes 35. However, the current flow times of this switching transistor, that characterize the control circuit, are constant.

Converter and the connection of the collector- A disadvantage of this arrangement is dart

Emitter path of the transistor (13) with this also in case of overload due to the constant control circuit egg art are provided that the Tran current flow times a through the smallest provided sistor (13) in the conductive Zi "= tand the current flow 30 switching frequency of the converter and The current flow time of the converter is shortened so that the filter choke flows a specified minimum current. By the addition of a main winding C) an additional winding Hch to the filter choke provided first resistance (4), which is the same winding as a measuring resistor in the load current path number as the main winding (3), and that the main winding (3) has to be counted as having a corresponding power loss and with a first resistance and as 35 a correspondingly high internal resistance of the resistance DC voltage converter connected to this resistance,
of the voltage divider (4,14) the additional winding The object of the invention is to provide a

(4) is used in such a polarity that the circuit arrangement of the type mentioned one side of the two windings to be indicated, in which the disadvantages mentioned are avoided at the other connected winding ends are homopolar 40. This is achieved according to the invention are. achieved that the control circuit of the converter and the

2. Circuit arrangement according to claim 1, connection of the collector-emitter path of the Tranda thereby characterized in that the two wick sistors are provided with this control circuit in such a way lungs (3,4) of the filter throttle from the same that the transistor in the conductive state, the electricity wire material or from materials with the same 45 flow times of the converter shortened that the filter throttle Temperature coefficient for the change in resistance, an additional winding exists next to a main winding, has the same number of turns as the

3. Circuit arrangement according to claim 2, main winding, and that as the first resistor characterized in that the two winding the main winding and as with this resistor lungs (3, 4) of the filter throttle thermally connected resistor of the voltage divider are coupled to each other. Additional winding is used in such a polarity that

the winding ends connected to one another on one side of the two windings are homopolar. An embodiment of a circuit arrangement

55 tion according to the invention is given below

Hand described in a basic circuit diagram.

The current drawn from a battery via input terminals 1, for example, is passed through an electrical

The invention relates to a switching ironic switch 2 and a filter throttle arrangement for overload and short circuit protection 6 ° with a main winding 3 and a capacitor 5 a DC / DC converter with a filter chain consisting of a filter chain to a load resistor 6. in the load circuit in which the electronic switch 2 is used in series with the load a first resistor is connected, between which a generator 7, for example sawtooth pulses from the load facing away from the connection and not generated, the switch 2 via a pulse This resistor connected terminal of the 65 width modulator 8 and a pulse shaper 9 er load a voltage divider made up of two resistors is sufficient.

is closed, in which the base-emitter path is also closed. If switch 2 is closed, a current flows

eiaes transistor to the tap of the voltage in the load resistor 6, and at the same time the