FR2636181A1 - CONTINUOUS POWER SUPPLY - Google Patents

Abstract

The invention relates to a DC power supply for an amplifier. It relates to a power supply comprising two voltage sources 4, 5 which are normally connected in parallel when a switch 8 is open. When the output signal of the amplifier exceeds a predetermined value, the switch 8 is closed so that the voltage sources are placed in series, given the arrangement of diodes 6, 7 across the voltage sources. Application to the supply of power amplifiers.

Description

The present invention relates to increasing the yield of

  amplifiers of high power, and it applies in particular to a switching device of power supplies, incorporated in a high power amplifier, between a serial assembly and a parallel assembly

so that the yield is increased.

  In industry, it is often desirable to have an amplifier capable of providing a large

  amount of energy, usually of the order of a few

  watts. A good example of a situation in which a

  such power is necessary is the field of communi-

  Amplitude modulation radio cations in which large amplifiers are used as emitter modulators. Another common use

  such important amplifiers is an excitatory circuit

  shaking or shaking tables used for

  resistance tests of products to vibrations. A pro-

  the problem posed by such important amplifiers is the

  overall poor performance of the amplifier which increases

  the cost of operation and construction. A

  definition of performance, generally accepted, is the

  port of useful power provided by a dynamic system to the power supplied to it. Industry has tried

  several times to increase the efficiency of an amplifier.

  However, the most used method is the technique of

  Pulse modulation of variable width. In one

  pulses of variable width, the amplitude of the signal transmitted to the amplifier remains constant while

  the width of the pulses varies. The advantage of modula-

  Variable width pulsation is that since the signal has a constant amplitude, the transistors used can work between the break and the saturation, so that the efficiency of the amplifier is increased by reducing the power dissipated in the circuit. In order to further increase the efficiency of the amplifier by reducing the power to be dissipated in the form of heat, a continuous power supply is commonly used.

  central socket with a pair of complementary switches

  Variable width pulse width modulated, mounted between the positive and negative voltage supplies and a load that is connected to the central tap. A problem posed by this arrangement is that the components incorporated in the switches must be chosen and adapted carefully.

  and precisely so that the sharing between

  pulsed pulse width modulators and the

  performance of these switches are maximized. If the

  the speed of one of the switches is not adapted to that of the complementary switch, a current is created and flows in the two switches so that the output of the

system decreases.

  According to the invention, the problems posed by the

  previous knowledge of increased efficiency of amplification

  are removed by using a power supply that has multiple DC outputs that can be switched from a parallel arrangement to a

  series according to the fact that the output signal of the

  plyer becomes too important for the voltage of one of the DC outputs of the power supply. When the voltage of the amplifier falls below the predetermined maximum value, the continuous output signals are returned to the parallel assembly so that the cooling and

  the heat dissipation in the amplifi-

  the amplifier and the power supply have better energy and money efficiency. An auxiliary advantage of the invention is the fact that, since the power supply is more efficient,

  a lower power supply can be used

  power supply for the amplifier, so that the

cost is even more reduced.

  Thus, the invention relates to a feed for

  amplifier with excellent performance.

  It also relates to a device for switching voltage sources between a series circuit and a parallel circuit.

  Other features and advantages of the invention

  tion will become more apparent from the following description,

  with reference to the accompanying drawings, in which:

  Figure 1 is a diagram of a common power supply

table according to the invention;

  FIG. 2 is a diagram of a second embodiment of

switchable power supply;

  Figure 3 is a diagram of the common power supply

  table connected to the circuit of an amplifier; and

  FIG. 4 is a diagram of another embodiment of

  switchable power supply, having

rators and triggers.

  FIG. 1 represents a switchable DC feed circuit 1 which has DC voltage sources 4 and 5 and diodes 6 and 7 arranged between terminals of

  output 2 and 3. The DC voltage source 4 is connected to

  The diode 7 has its anode connected to the positive terminal of the voltage source 4 and has its negative terminal at the negative output terminal 3 of the DC supply circuit 1. its cathode is connected to the positive terminal of the voltage source 5 and to the positive output terminal 2 of the continuous supply circuit 1. The diode 7 has its anode connected to the positive terminal of the voltage source 4 and its cathode is connected to the positive terminal of the voltage source 5 and to the positive output terminal 2 of the continuous supply circuit 1. The diode 6 is connected, by its cathode, to the negative terminal of the voltage source 5 and,

  at its anode, at the negative terminal of the voltage source 4.

  A mechanical or electrical switch 8 is mounted between

  the anode of the diode 7 and the cathode of the diode 6.

  In use, when the switch 8 is open, the DC voltage sources 4 and 5 are connected in parallel and the voltage at the terminals 2 and 3 is equal to the voltage of one of the sources 4 or 5 (in FIG. the assumption that they are both equal). When the switch 8 is closed, the voltage sources 4 and 5 are put in series between the terminals 2 and 3, the positive terminal of the source 4 being connected by the switch 8 to the terminal

negative from source 5.

  As can be noted in FIG. 2, any number of voltage sources can be switched by adding two diodes and one switch per additional voltage source. The circuits of FIGS. 1 and 2 use the same references, followed by the prime sign in FIG. 2, to designate common functions. More

  components described with reference to FIG.

  switchable power supply 1 'shown in FIG. 2 has a DC voltage source 9 connected in parallel with the

  source 5 '. A diode 10 is mounted between the positive terminals

  Sources 5 'and 9, the cathode being connected to the voltage source 9 and the positive output terminal 2'. The diode 11 is mounted between the negative terminals of the voltage sources 5 'and 9, its cathode being connected to the voltage source 9. A second electrical or mechanical switch 12 is mounted between the anode of the diode 10 and the cathode of the the

diode 11.

  In use, when the switches 8 'and 12' are open, the voltage available at the terminals 2 'and 3' is equal to the parallel supply voltage of the sources 'and 9 in series with the voltage source 4'. If the switch 8 'is open and the switch 12 is closed, the source 9 is connected in series with the combination in

  parallel sources 4 'and 5'. When the two

  8 'and 12 are closed, sources 4', 5 'and 9 are connected in series and the voltage between terminals 2' and 3 '

  is equal to the sum of the values of the voltage sources.

  An amplifier shown in block form in FIG. 3 comprises two amplifiers A1 and A2 driving four transistors T1-T4 which are mounted with a bridge configuration having output terminals 40 and 34 connected to a load. The amplification circuit shown is known in the industry and is shown merely as an illustration of the interconnection of the circuit 18 of FIG.

  switching (described below) and the amplification circuit

  er. This is not a novelty in the

framework of the invention.

  Figure 4 shows an application of the food

  switchable switch 1 in which the switch 8 is replaced by a switching circuit 18. Transformer 29 having primary 31 connected to a power supply

  external phase not shown, also includes

  coils which include filtering and rectifying devices so that continuous supplies 14 and 16 are formed. The DC power supply 16 is connected to a switching circuit 18 for transmitting supply and reference voltages to the components of the circuit 18. The switching circuit 18 comprises, as main components, comparators 20 and 22. Zener 24 and 26 are connected in series with a current limiting resistor 29 between the positive terminal 17 and the negative terminal 15 of the DC supply 16 so that a set point is formed for the comparators 20 and 22. A divider voltage is for connecting the resistors 28 and 30 in series between the positive terminal 17 and the connection 25 of the zener diodes

  24 and 26. The connection of the resistors 28 and 30 is connected

  to a comparator non-inverting input terminal 19 so that a reference voltage is present at the terminal 19. The resistor 32 is connected between the comparator 20 terminal 19 and the amplifier circuit ground 34 ( shown in Figure 3). Resistors 35 and 36 are connected in series between the connection 25 and the negative terminal so that a voltage divider is formed, the connection of the resistors 35 and 36 being connected to the inverting input terminal 21 of the comparator 20. Resistance 37 is

  mounted between the output terminal 40 of an amplifying circuit

  3, and the inverting input terminal 21 of the comparator 20. The output terminal 42 of the comparator 20 is connected so that it triggers the input 46 of the timer circuit 44. A resistor network is connected to the comparator 22, substantially in the form of an image of the network connected to the comparator 20. Resistors 48 and 50 are connected in series between the connection 25 of the Zener diodes 24 and 26 and the negative terminal 15 of the DC supply 16. The connection of the resistors 48 and 50 is connected to the inverting input terminal 27 of the comparator

  22. The resistor 52 is connected between the inverting input

  27 of the comparator 22 and the ground 34 of the ampli-

  shown in Figure 2. The resistors 54 and

  56 are connected in series so that they form a cir-

  baked voltage divider between the connection 25 and the positive terminal 17 of the DC power supply 16, the connection of the

  resistors 54 and 56 being connected to the input 23 of

  inversion of the comparator 22. A resistor 58 is connected between the positive output 40 of an amplifier circuit and the non-inverting input 23 of the comparator 22. The output

  comparator 22 is connected to the trigger input

  46 of a timer or monostable circuit 44.

  The networks of resistance that link comparisons

  20 and 22 at the output 40 of the amplifier and at the positive and negative terminals 17 and 15 of the DC power supply 16 have been chosen so that each comparator

  receive differentially the output voltage of the ampli-

  indicator and the supply voltage continues. Resist

  similarly connected to the two comparators have almost equal values. As a result, as shown in FIG. 3, the resistors 28, 35, 48 and 54 have an equal or approximately equal value and the resistors 30, 36, 50 and 56 have the same values as the resistors 32, 37, 52 and 58 The use of equivalent resistance values enables comparators 20 and 22 to change state for the same voltage ratio to

half-cycles that alternate.

  It should be noted that comparators 20 and 22 are

  components paired in the same circuit board.

  so that they share a common source of voltage between a terminal 62 connected by the resistor 29 to the positive terminal 17 and an input terminal 64 connected to the

  negative terminal 15 of the continuous supply 16.

  The circuit which provides support and proper biasing of the timer 44 comprises a resistor 66 and a capacitor 68 connected in series between the connection 70 and the negative DC supply terminal 16. The connection of the components 66 and 68 is connected to the input terminal of

  threshold 72 and the trigger input 46 of the timer 44.

  A positive voltage is transmitted to the timer 44 by

  connection of the pin 74 to the positive terminal 17 by the in-

  A ground pin 76 is connected to the negative terminal 15. The capacitor 78 is mounted.

  between the input 80 of the timer 44 and the negative terminal 15.

  A resistor 84 is mounted between the connection 70 and the reset pin 82 of the timer 44, a capacitor 86 and a resistor 88 being mounted between the pin 82 and

  the negative terminal 15 so that a low voltage is applied

  to an output pin 92 when energy is initially transmitted to the circuit, up to the total load

  of the capacitor 86. A capacitor 90 for the derivation of

  It is connected between the connection 70 and the negative terminal 15. The output pin 92 of the timer 44 is connected by a current limiting resistor 94 to the gate 96 of a field effect transistor 100. The drain 104 of the transistor 100 is connected to the positive terminal 11

  of the continuous supply 14 and the anode of a diode 110.

  The source wire 106 of the transistor 100 is connected to the

  cathode of the diode 109 and the negative terminal 15 of the

  16. The cathode of the diode 110 is connected to the positive terminal 17 of the DC power supply.

  16. The anode of diode 108 is connected to the negative terminal

  13 of the continuous supply 14.

  The switching circuit according to the invention increases the efficiency of an amplifier power supply by switching DC power supplies 14 and 16 from the parallel arrangement in series when the amplifier exceeds a predetermined maximum output voltage. The predetermined maximum value is the ratio

263618 1

  the voltage of the amplifier to the voltage across the DC supply 16, and is determined by the

  maintenance resistance networks connected to comparisons

  20 and 22 as previously described. Initially, the DC supplies 14 and 16 are connected in parallel, the outputs 42 and 60 of the comparators 20 and 22 are at a high voltage level and accordingly the timer 44 is not triggered. Further, after initialization, the capacitor 86 begins charging and places a low voltage at the output pin 92 and in this way it keeps the transistor 100 in the non-conductive state and the DC power supplies 14 and 16 in parallel. When the output signal of the amplifier at the terminal 40 exceeds the predetermined ratio, even temporarily during a positive half cycle, the comparator 20 creates a low voltage level at the output 42 and triggers the timer 44 which switches its output signal. at pin 92 from a low voltage to a high voltage. Similarly, if the output signal of the amplifier controlled at the

  pin 40 exceeds the predetermined ratio during the half

  Negative cycle, the comparator 22 creates a low level output signal at pin 60 which also causes the timer 44, at pin 92, to trip from a low voltage to a high voltage. In this way, if the

  output signal from the amplifier, at pin 40, de-

  passes the predetermined ratio in a positive half cycle or

  negative, the timer 44 is triggered.

  When the timer 44 is triggered, a high logic level appears at the output pin 92 of the timer

  44 and causes the transistor 100 to turn on

  and creating a flow path for a current

  which electrically supplies the power supplies 14 and 16 in series.

  If the output signal of the amplifier at pin 40 is between the normal limits, i.e. is less than the predetermined ratio, the comparators 20 and 22 do not trigger the timer 44 so that the output signal of pin 92 has a low level which keeps transistor 100 in the open state. When the transistor is open, the DC supplies 14 and 16 are connected in parallel through diodes 108 and so that the power to be dissipated by a single power supply is reduced. The steady state of the timer 44 is the creation of a low level signal at the pin

  92 output and accordingly the transistor 100 is normal

  in the nonconductive state and the power supplies 14 and

  16 are normally connected in parallel.

  The timer 44 or monostable circuit has the role, in the switching circuit 18, to give a hysteresis phenomenon to the switching of the DC supplies 14 and 16. The timer 44 also determines the maximum frequency at which the switching circuit 18 can

  switch on the continuous power supplies 14 and 16. After

  initially initiated by one of the comparators 20 and 22, the timer 44 transmits a high level signal to the pin 92 for a predetermined period. When a second signal or a multiple trigger signal is received during the predetermined period during which the timer 44 transmits a high signal to its output pin 92, the timer 44 is retriggered and the transistor 100 remains in the conductive state. As a result, the frequency

  maximum that can be damaged is inversely proportional-

  at the predetermined period during which the timer 44 transmits a high level signal to the pin

  92 following its trigger.

  If a hysteresis phenomenon or a maximum switching frequency is undesirable, the timer 44 may be omitted and the comparators 20 and 22 may be arranged in the manner of a Schmidt flip-flop so that they properly control the transistor of commutation.

- 2636181

Claims (8)

  A power supply for transmitting a voltage to a voltage amplifier having internal signals derived from an input signal, said power supply being characterized by comprising a first and a second voltage source (4, 5). ), a detection device connected in such a way that it receives the amplifier signals and voltages corresponding to the voltage of the first voltage source, so that it controls the level of the voltage difference between the signals of the first voltage source, amplifier and the first voltage source, and a switching device (8) for serializing the   first and second source of tension when the   detection system has controlled a minimum level of   voltage, since the switching device is   to set the first and second voltage sources in parallel when the sensing device has controlled a voltage difference greater than the minimum level of voltage difference.   2. Feed according to claim 1, characterized   in that the detection device comprises a comparison device (20, 22) for determining the voltage difference between the amplifier signals.   and the voltage across the first voltage source.   3. Feed according to claim 1, characterized   in that the switching device comprises a switch (8), a first and a second diode (6, 7).   and a control device for controlling the communication   tator, the latter being connected on one side to the posi-   the first voltage source and at the anode of the first diode, and on the other side to the negative terminal of the second voltage source and the cathode of the second   diode, the control device being connected to the switching   to the closed state and the open state, the cathode of the first diode being connected to the positive terminal of the second voltage source, the anode of the second diode being connected to the negative terminal of the first source of tension.   4. Feed according to claim 3, characterized   in that the control device comprises a   timer (44) connected to the output of the comparison device   sound and controlled by the sensing device so that it   closes the switching device for a period of   determined after being activated by the de-   which controlled a minimal difference in voltage.   5. Feed according to claim 4, characterized   in that the comparison device (20, 22) comprises a device for determining the difference of tension controlling the timer.   6. Feed according to claim 1, characterized   in that the signals of the amplifier are   killed by the output signal of the amplifier.   Switchable power supply, characterized in that it comprises a first and a second voltage source (4, 5), a switch (8) connected to the voltage sources, and a current direction device (6, 7).   mounted between each of the voltage sources and the switching   to ensure that voltage sources are connected in series when the switch is closed or   when the switch is open or in the non-conductive   the current direction device puts the sources parallel voltage.   Switchable power supply according to claim 7,   characterized in that the neck direction device   first diode (6, 7), the first diode being connected between the positive terminals of the first and second voltage sources, the second diode being   diode being mounted between the negative terminals of the first   and the second voltage source, the switch (8) being mounted between the anode of the first diode and the cathode of the second diode, so that the diodes are 'reverse biased when the switch is closed or driven and are polarized in the forward direction when the   switch is open or not driving.