FR2529038A1 - PULSE GENERATOR CIRCUIT - Google Patents

Abstract

THE PULSE GENERATOR CIRCUIT INCLUDES A DELAY LINE TYPE PULSE CONFORMING NETWORK 10 AND A SUPPLY SOURCE INCLUDING A RESONANT CHARGING CIRCUIT 11 CAPABLE OF CHARGING THE PULSE CONFORMING NETWORK AT A DESIRED ELECTRICAL VOLTAGE. A FIRST SWITCH 14 IS MOUNTED IN SERIES WITH A USER LOAD 12 AT THE TERMINALS OF THE PULSE CONFORMING NETWORK AND SUITABLE TO CAUSE THE LAUNCH OF A PULSE OF ENERGY THROUGH THE USER LOAD, AND A SECOND WITH SWITCH 15 IS MOUNTED IN PARALLEL THE USER LOAD 12 AND SUITABLE TO ACT BEFORE THE END OF THE PULSE GENERATED BY THE PULSE CONFORMING NETWORK 10 TO END THE ENERGY PULSE, AT LEAST ONE OF THE FIRST AND SECOND SWITCHES BEING A DEVICE N ' ADMITTING TO BE CROSSED BY AN ELECTRIC CURRENT ONLY IN A DIRECTION SO THAT THE ENERGY WHICH IS NOT DISSIPATED IN AN ENERGY PULSE IS CONSERVED IN THE PULSE CONFORMING NETWORK TO BE PART OF THE ENERGY AVAILABLE FOR A LATER PULSE OF ENERGY. USE IN PARTICULAR IN PULSE CIRCUITS IN WHICH A PULSE CONFORMING NETWORK IS LOADED THEN UNLOADED THROUGH A USE LOAD.

Description

The present invention relates to pulse generator circuits,

  and in particular to circuits of the kind in which a pulse shaping or delay line network is charged by a power source, and then discharged through a usage load to generate the pulse. There are known pulse generator circuits of the above type which use an artificial delay line.

  or pulse shaping network formed by inductances

  these and by capacitors that simulate the properties of a delay line Such circuits have been used since

  many years to generate impulses in

  a discharge path from the shaping network

  pulses and passes through a suitable use load.

  In addition, various suggestions were made to end

  the impulse thus produced in order to obtain an impulse

  variable and adjustable duration of life When terminating

  such an impulse, it is possible to return a fraction

  tion of the energy not dissipated at the power source.

  One of the aims of the invention is to provide a pulse generator circuit intended to provide a pulse of

  variable width from a pulse shaping network

  of fixed length, and to store unused energy

  on the pulse shaping network, thus enabling a significant reduction in the voltage

  of excitation requested from the main power source.

  According to the present invention, there is provided a pulse generator circuit which comprises a shaping network

  delay-line type pulses, a source of

  comprising a resonant charging circuit adapted to charge the pulse shaping network to a desired voltage, a first switch connected in series with a load of use at the terminals of the shaping network

  pulses and adapted to provoke the launching of an impulse

  energy flow through the load, and a second switching

  in parallel with the load and adapted to terminate the energy pulse, at least one of the first and second switches being a device which does not admit to being

  crossed by a current only in one direction.

  The characteristics and advantages of the invention

  more fully from the detailed description which

  is given below by way of non-limiting example in

  reference to the accompanying drawings, in which:

  Figure 1 is a simplified circuit diagram of a first embodiment of the invention; and

  Figures 2 and 3 are similar diagrams representing

  both variants of the invention.

  According to the arrangements shown in FIG. 1, a pulse shaping network 10 is formed by an assembly of inductors L and capacitors C. The network can be charged to a desired potential having the necessary polarity by a charging circuit. resonance load effect This charging circuit will not be described in detail, since the circuits of this kind are well known. The utilization load 12 is connected between one of the terminals of the network 10 and a common line 13, which can be put to

  earth A first switch 14 is connected between the

  terminal of the network 10 and the common line 13, while a second switch 15 is connected in parallel with the user load 12 It is necessary that at least one of the two switches is of a type suitable to allow the electric current to pass only in one direction when closed.

  The load of use 12 will usually be impedance

  it is relatively low compared to the dynamic impedance of the resonant circuit, in which case, when the network is charged by the power source 11, the charging current will flow through the usage load 12 if the switch 15 is open. use is non-resistive, or if it is at high impedance, the switch 15 can be closed during the network load In the latter case, the switch 15 will be open once the network is closed.

find charged.

  The passage of a pulse of energy through the use load 12 is triggered by closing the switch 14, which causes the discharge of the network through the load of use The flow direction of the current during this discharge is determined by polarity

  of the charging network The impulse is terminated prematurely

  When the network is short-circuited, the energy still present in the network gives rise to a transient overcurrent, and consequently to a polarity inversion. the voltage across the capacitors of the network This process takes place almost without losses Since at least one of the two switches 14 and 15 allows the passage of the current in only one direction, the reverse load of the network can not be dissipated because this would require the passage of a current in the opposite direction The source

  It then recharges the network as before

is lying.

  If the network has a long pulse length compared

  At the desired pulse duration, a large proportion of the energy stored in the network is kept, which reduces the input voltage required by the resonant charging circuit. If the supply voltage is Vs and the voltage remaining on the network is VR, the voltage V to which the network is loaded has for expression: Vc = 2 Vs + VR Thus, for a particular value of V, Vs is reduced especially as VR remains strong As a For example, if the network pulse length is twice the desired pulse duration, the supply voltage is reduced to about 15% of that needed if all accumulated energy is dissipated. that the accumulated voltage depends on the duration of the pulses, and the supply voltage must therefore be chosen so that it satisfies the charging requirements after

the longest pulse requested.

  The diagram of FIG. 1 shows the mounting that is necessary if the user load 12 and the switch 14 both have to have one of their terminals grounded. For other types of user loads and switches to which this condition is not imposed, he

  can be used to circuits arranged in a light-

  different without departing from the scope of the invention.

  Figure 2 represents the case in which only the load used

  The reader is connected to the common line 13 by one of its terminals, the circuit being otherwise exactly the same as

that of Figure 1.

  The switches 14 and 15 may take various different forms, as long as at least one of them can only pass a current in one direction, as indicated above. The switch 14 may for example be a transistor, a thyristor or thyratron, all of which satisfy the above condition. Similarly, switch 15 may be a thyristor, a

  thyratron, or a saturable inductor Figure 3 shows

  the embodiment considered above when the utilization load is a magnetron oscillator, the switch 14 a thyristor, and the switch 15 a

saturable inductance.

  The switch 15 is the fundamental component, in this

  that its operation fixes the precise duration of the impulse.

  It is clear that a circuit of temporisa-

  tion and control of one form or another for

  If both switches must be closed in order to allow the network to charge, then it must be of a type suitable for allowing the current to flow in both directions, since the charging current and

  discharge current flow here in opposite directions.

Claims (5)

  1 pulse generator circuit comprising a line-type pulse shaping network (10)   delay and a power source with a cir-   resonant charging furnace (11) capable of charging the pulse shaping network to a desired electrical voltage, characterized by a first switch (14) connected in series with a user load (12) across the network   pulse shaper and adapted to cause the launcher   energy impulse through the load used   the reader, and by a second switch (15) connected in parallel with the user load (12) and adapted to act before the end of the pulse generated by the network   pulse shaper (10) to terminate the pulse.   energy, at least one of the first and second   switches being a device which does not admit to being   poured by an electric current only in a sense so that energy that is not dissipated in a pulse   energy stored in the network conforms to   to be part of the energy available   nible for a subsequent energy pulse.   Circuit according to claim 1, characterized   characterized in that the power supply (11) is connected to the junction between the first switch (14) and the user load (12).   Circuit according to any of the claims   cations 1 and 2, characterized in that the or   (14, 15) admitting to being traversed by a cou-   only in one sense are thyristors.   Circuit according to any of the claims   1 to 3, characterized in that one of the first and second switches accepts the passage of a current in both directions.   Circuit according to claim 4, characterized in that said switch allowing the passage of a current in both directions is an inductance to saturable core.   Circuit according to any of the claims   1 to 5, characterized in that the load used   satrice (12) is a magnetron oscillator.