FR2512290A1 - - Google Patents

Abstract

THE INVENTION RELATES TO A COMBINED NETWORK MONITORING AND CONTROL REGULATION DEVICE INTENDED FOR A DC POWER SUPPLY, OF THE PULSE WIDTH MODULATION SWITCHING TYPE. THE TECHNICAL PROBLEM IS TO USE A SMALL NUMBER OF COMPONENTS. THE DEVICE ACCORDING TO THE INVENTION INCLUDES MEANS 40 FOR DERIVING A SAMPLE OF ALTERNATIVE VOLTAGE REPRESENTATIVE OF THE VOLTAGE OF A SUPPLY LINE, FIRST MEANS 44, 46 FOR CONVERTING THE SAID ALTERNATIVE VOLTAGE BETWEEN A CONTINUOUS VOLTAGE, REGULATION OF THE MEANS VOLTAGE 50 CONNECTED TO SAID FIRST MEANS OF CONVERSION 44, 46 SO AS TO PROVIDE A REGULATED CONTINUOUS OUTPUT VOLTAGE AND SECOND MEANS 80, 82, 84, 86 TO CONVERT THE SAID ALTERNATIVE VOLTAGE INTO A CONTINUOUS VOLTAGE INCLUDING MEANS 82, 84, 86 FOR DETECTION OF FAULT CONDITIONS OF THE SAID POWER LINE AND OF THE MEANS 62 RELATED TO THE SAID SECOND MEANS OF CONVERSION 80, 82, 84, 86 IN ORDER TO GENERATE CONTROL SIGNALS ACCORDING TO THE SAID FAULT STATES. THE INVENTION APPLIES IN PARTICULAR TO POWER SUPPLIES CONTROLLED BY AN INTEGRATED CIRCUIT.

Description

t 2512290 "Combined network monitoring and control device

  The present invention relates to control circuits for a switching power supply.

  voltage regulation in general, and in particular a device

  combined network monitoring and control regulator for DC power supply, type

  Pulse width modulation switching.

  Width modulation switching of im-

  drive is a well known regulatory technique that is

  used in some DC power supplies

  The main benefit brought by this type of regulation is a greatly reduced power dissipation within

  diet itself, while maintaining a degree of

  relatively high regulation; it follows that we can

  tend to use transformers and other components

  of smaller dimensions and less heavy.

  Traditional protection circuits are known

  nels which are intended to perform an automatic shutdown in the event that faults occur on the network; such circuits include Crowbar overvoltage protection circuits of the tyristors and unijunction transistors controlled on

  also knows about traditional voltage regulators de-

  However, the additoron dez circ: its and components annihilates the advantage

  modulation switching technique

  impulse width has been sought to incorporate into a

  commercial version of a modular switching power supply

  of pulse width, specific functions of

  tection and control while maintaining the level of integration

  design by keeping a number of components and

  costs, and without unduly increasing the consumption of

power.

  In accordance with the present invention, a device

  Simple combined network monitoring and control control system for a switching power supply

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  protection and control functions using a relatively small number of components Specifically, the proposed commercial embodiment, which includes a single commercial voltage regulation integrated circuit, a transistor and a small number of associated passive components, performs a detection of the value of the network, a detection

  of a network frequency drop, a regulation of the

  control voltage, a reference voltage generation, and

  the generation of certain transient state control signals

  res (increase or decrease in power).

  It is therefore an object of the present invention to provide a combined network monitoring device and

  control regulator for a power supply

  tation. It is yet another object of the invention to provide a new and relatively simple circuit which performs a large number of protective and control functions,

  to ensure the proper functioning of an electronic system

tronics.

  This is yet another object of this

  to provide a valid and secure set of conditions if-

  to the control circuits of a switching power supply

  modulation of the pulse width regardless of the

  the network in a given range, regardless of the

  increase the duration of the decrease, the rate of repetition

  opening and closing cycles, or state

of the previous signal.

  It is a further object of the present invention to provide a combined network monitoring and control regulation device for a simple switching power supply which uses relatively few elements in view of the high number of functions performed. ,

and that is not expensive.

  Other features and advantages of the

  will be apparent from the following description, made as a

  -3- illustrative with reference to the accompanying drawings, in which

  FIG. 1 is a block diagram of a food

  switching device using a combined monitoring device

  network launcher and control controller according to the present invention, and Fig 2 is a detailed diagram of a mode of

  preferred embodiment of the present invention.

  In fig 1 we see a circuit 12 of recovery-

  and filtering which receives via a

  trainer 10 an AC voltage from a source of

  power The rectified and filtered DC voltage thus obtained

  naked is applied to a switching output stage 14 which

  powers one or more regulated DC voltage outputs.

  In a commercial version of the invention, the output stage

  The switching circuit 14 comprises two transistors which are alternately

  conductors at a frequency of 20 kHz, in order to drive the

  primary bearing of an output transformer.

  see one or more secondary windings, including each

  an associated recovery and filtering circuit,

  to produce the output voltages Samples of the output voltages are fed back to a control circuit of

  circuit 16 which compares the reaction sample with a voltage

  predetermined reference voltage and which, from this comparison, creates a control logic signal, indicating that the regulated output DC voltage is higher or lower than the nominal output level The control logic signal is applied to a control circuit 18 logic and control which provides pulse width control signals, so as to drive the switching output stage 14 In the

  commercial version of the invention, the logic control circuit

  that is driven by a 40 kHz clock signal which is divided and modified by many control signals, including the control logic signal from the control controller 16, so as to generate control signals width

  at 20 kHz to drive the switching output stage

  The control elements can advantageously be constituted by transistors whose emitter is grounded and which are controlled by the width control signals.

  impulse, so as to provide a sufficient steering current

  firing for the exit floor. A combined network monitoring and control regulation device 20 is connected to the transformer 10 so as to perform the detection of the value of the network.

  detection of a decrease in the frequency of the network, the

  the control voltage, the regeneration voltage

  and the generation of valid and safe signal states

  pilot circuit 18 and one or more circuits indicative of

  tors. The device 20 for monitoring the network and

  control regulation is shown in detail in FIG.

  The power required to operate the circuit is provided by a secondary winding 40 of the transformer 10 providing an AC voltage of 16 V; this power is therefore derived directly from the alternating voltage of the network and constitutes a

  representative sample of the latter The alternating voltage

  It is applied via a fuse 42 to a diode 44 performing a half-wave rectification and a filter 46 so as to provide a nominal DC voltage of + 20 V.

  This voltage is applied to a control circuit 50 represented

  generally felt by a broken line.

  The regulating circuit of the embodiment

  commercial is an integrated circuit of voltage regulation dis-

  commercially available and known as A-723 Ce-

  during, important details of this circuit have been represented and will be described because they relate to the functioning of the

  In addition, the voltage regulator could be

  in discrete components, although the benefits of gain in

  congestion, cost, and, perhaps, consumption would be

  due. In the control circuit 50, an output series transistor Q O is connected between the power supply terminals V + and VC and a voltage output terminal V O The output terminal V O is connected to ground via

  a diode 52 and resistors 54 and 56 connected in series.

  + 10 V DC voltage is supplied to the terminals

  resistors 54 and 56, and is available for different

  the switching power supply

  The resistors 54 and 56 are connected to the inverting input (INV) of a differential amplifier iCnterne DA, in order to provide a divided reaction voltage, for controlling the optical amplifier of the serial transistor. QO 'An internal RF voltage circuit (REF CKT) provides a reference voltage of + 7'15 V which is made available to the external circuits via the

  VREF terminal The direct input (INON INV,) of the separate amplifier

  internal cavity DA is also connected to the regeneration voltage

  of + 7.15 V, the common emitters of the transistors con-

  the differential amplifier are connected by the interme-

  a source of current to ground through the VSS base voltage terminal A suitable compensation capacitor 58

  is connected between the IINTIV and FREQ COMP terminals of the

50.

  A current limiting transistor QCL is provided

  inside the regulator 50 in order to block this transistor se-

  O O in certain circumstances which will be described in

  The base of the QCL transistor is connected by

  The collector of the switching transitor 62 is also connected by a load resistor 64 to the rated power supply with a CUR LIM terminal and a base current limiting resistor O at the collector of a switching transistor 62.

  continuous + 20V, while its transmitter is grounded.

  The transmitter of the current limiting transistor QCL is connected

  to the ground via the terminal of detection of cou-

  CUR SEN and two low value resistors 68 and 70.

  Two blocking diodes 72 and 74 ensure that the junction point

  resistance 68 and 70 is maintained at a level of

  close to that of the mass under all operating conditions This junction point is also connected by

  through the fuse 42 at one end of the

  secondary bearing 40, so as to provide a reference to the network monitoring circuit which comprises the transistor of

switching 62 above.

  A diode 80 and a capacitor 82 are connected

  in series at the terminals of the secondary winding 40, and a

  The resistor 84 connects the junction of these last two elements to the base of the transislor 62. A bias resistor 86 is connected between the base of the transitor 62 and the ground. Under normal operating conditions, the capacitor 82 charges at the nominal value of + 20 V, which makes the transistor 62 conductive The collector voltage of the transistor 62 falls to a value close to that of the ground as long as the transistor is saturated, which blocks the transistor QCL inside the regulator circuit 50 When the QCL transistor is blocked, the

  transistor output series Q O is made conductive, which allows

  puts the regulated voltage of + 10V to increase to its value

  steady state while the transistor Q 0 becomes fast

  The + 10 V voltage is applied as a positive feedback via resistor 90 to the

  transistor 62, which reinforces the driving state of the trans-

  sistor 62 and this results in a fast switching of the DC output of + 10 V.

  The time constant of the impedance circuit de-

  written above comprising the capacitor 82 and the resistor 84 is chosen to be relatively short, for example

  short enough to detect a fall in the corresponding network.

  in such a situation or if the

  When the voltage of the mains voltage drops below a predetermined value, the capacitor discharges to a point for which the transistor 62 begins to block, the collector voltage of the latter increasing while the transistor loses its state. This action in turn makes the transistor QCL conductive by blocking the output series transistor Q0. Because the + 10V output drops and the control circuit limits the current, the voltage at the terminal

FREQ COMP decreases rapidly.

  From the description that has just been given of the func-

  In the circuit, it can be seen that status signals indicating the condition of the regulator on the collector of the transistor 62 and the terminal FREQ COMP are generated. During the actual operation of the regulating circuit 50, the voltage of the collector of the transistor 62 is low and the voltage on the terminal FREQ COMP is high If a fault occurs as described above, the collector voltage of the transistor 62 rises and the voltage of the terminal FREQ COMP decreases As a result, the collector of the transistor 62 is connected via resistors 94 and

  96 to the bases of the pilot transistors 18-1 and 18-2, the cir-

  cooked logic control and control 18 (see fig 1), from

  to block the control signal the pulse width at the switched output stage during the occurrence of a

  defect and in such a way as to allow the passage of

  the pulse width during operation -

  The low level on the FREQ COMP terminal of the

  gulator 50 during the occurrence of a fault is sent by

  via a diode 100 to certain circuits of indica-

  power supply, in order to provide information regarding the operating state of the voltage regulator, and consequently,

of food.

  From the description that has just been given, he

  that a combined network control and control control device provides a set of valid and safe status signals to the control circuit of a PWM switching power supply for any voltage of the network in a given range, regardless of the level of increase, the duration of the fall of the grating, the rate of repetition of the closing and opening cycles or of an earlier signal state. Similarly, the voltages a8 are supplied. 2512290

reference numbers.

  The above description has only been provided to

  as a non-limitative example, and it is obvious that we can make changes or variants without going out for

  both of the scope of the present invention.

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Claims (2)

CLAIMS) A combined network control and control regulation device, characterized in that it comprises: means (40) for deriving an AC voltage sample representative of the voltage of a supply line; first means (44,46) for converting said alternating voltage into a DC voltage; voltage regulating means (50) connected to said first converting means (44,46) so as to provide a regulated continuous output voltage; second means (80,82,84,86) for converting said AC voltage to a DC voltage, said second converting means including means (82,84,86) for detecting fault conditions of said DC line; feeding, and; means (62) coupled to said second converting means (80,82,84,86) for generating control signals in accordance with said fault states.   2) A combined network control and control control device according to claim 1, characterized   in that said voltage regulating means (50) comprises   a series element (Q 0) and a control circuit of this latter   an element comprising an operational amplifier (D AM,   said voltage regulating means (50) further comprising means (CL>) related to said control signal generating means (62) for disabling said serial element (Q 0) in   function of a fault condition detected.   Combined network control and control control device according to claim 2, characterized in that said second conversion means (80,82,84,86)   comprise a diode (80) and in that said means for detecting   fault condition include an impedance network   (82,84,86) having a predetermined time constant -   -) Combined network control and control control device according to claim 3, characterized in that said control signal generating means comprises switching means (62) connected to said impedance networks (82,84,86 ). A combined network control and control control device according to claim 4, characterized in that said switching means comprises a transistor (62) whose base is connected to said impedance network (82,84, 86).   Combined network control and control control device according to claim 5, characterized in that the regulated continuous output (V 0) of said voltage regulation means (50) is connected to the base of said transistor switching (62).   7?) A combined network control and control control device according to claim 2, characterized   in that said voltage regulating means (50) comprises   furthermore, means (100) for signal generation   states indicating the operating status of the voltage regulator. if we.