SU1422328A1 - Stabilized single-ended d.c. voltage converter - Google Patents

Description

(21) 4216829 / 24-07

(22) 03/30/87

(46) 09/07/88. Bul, № 33

(71) All-Union State Design and Survey and Research Institute of Energy Systems and Electric Networks Energosetproekt

(72) V.L.Shapovalov, Yu.P.L. Skovsky and P.V.Vnukov

(53) 621.314.632 (088.8)

(56) U.S. Patent (J 4,481,564, CL H 02 M 3/335, 1984.

European patent number 0170944, cl. H 02 M 3/338, 1987.

(54) STABILIZED ONE-TAKE CONSTANT VOLTAGE CONVERTER

(57) The invention relates to converter technology and can be used in power sources, including secondary power sources. The purpose of the invention is to increase reliability by providing

soft start and short circuit current reduction. This is ensured by the fact that a resistor 16 connected in series between the additional winding 4 of transformer 3 and diode 17 is inserted into the converter, and the current sensor 12 in the emitter circuit of transistor (T) 1 is made in the form of a non-linear element shunted by capacitor 24 series-connected resistors 21, 22 and a diode 23 connected in series with the first resistor 21 and in parallel with the second resistor 22. In this case, in the locking circuit T 1, the emitter of the first transistor 13 is connected to the emitter T 1, the collector T 14 is connected n with base T 1 and T emitter 14, a phototransistor 9, and a second optocoupler output l5 capacitor connected to a negative potential and the input voltage to the common point 4 and further secondary winding 5 of the transformer 3. 1-yl.

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The invention relates to electrical engineering and can be used in power sources, including secondary power sources of radioelectric equipment.

The aim of the invention is to increase reliability by ensuring smooth starting and reducing short-circuit current.

The drawing shows a circuit diagram of a stabilized, single-ended constant voltage converter.

The stabilized single-ended DC / DC converter contains a power transistor 1, a voltage surge limit circuit 2 and, a transformer 3 with an additional 4 and a secondary 5 windings, a rectifier 6, a filter 7, an error amplifier 8, an optocoupler 9, an RCD chain 10, a resistor 11 bias, current sensor 12, the circuit of locking the power transistor on two transistors 13 and 14, the base 15 and the charging

16 resistors, decoupling diode 17, capacitor 18, resistors 19 and 20, voltage divider, resistors 21

and 22 current sensors, a current sensor diode 23 and a shunt capacitor 24.

Through the bias resistor 11, the vase of the power transistor 1 is connected to the positive output of the input voltage source and through the RCD chain 10 to the secondary winding 5 of transformer 3. The collector of transistor 1 is connected to the primary winding of voltage transformer 2. The emitter of transistor 1 is connected via a current sensor 12 to a negative terminal of an input voltage source. The scheme of locking the key transistor 1 consists of transistors 13 of the pp type and 14 pp types. The emitter of the transistor 13 is connected to the emitter of the key transistor 1, the collector of the transistor 13 is connected to the base of the transistor 14. The collector of the transistor 14 is connected to the base of the key transistor 1.

Additional winding 4 tr of the transformer 3 through the resistor 16 and the diode

17cw is connected to a capacitor 18, which is connected to a voltage divider consisting of series-connected resistors 19 and 20, the midpoint of the latter is connected to the collector of the phototransistor of the optocoupler 9 through a resistor 15 - to the base transis

5 0 5

0

five

five

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five

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torus 13. The emitter of the transistor 14, the resistor 20 and the phototransistor emitter of the optocoupler 9 are connected to the common point of the additional 4 and secondary 5 windings of the transformer 3, as well as the negative terminal of the input voltage source.

The current sensor 12 consists of series-connected resistors 21 and 22, shunted by a capacitor 24, and a diode 23 connected in series with a resistor 21 and in parallel with a resistor 22.

The stabilized single-ended DC-DC converter works as follows.

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After supplying the input voltage through the bias resistor 11 and the base-emitter junction, transistor 1 begins to flow the initial current simultaneously through the transformer primary winding. 3 the collector current of this transistor flows. The voltage induced at the same time on the secondary winding 5 of the transformer 3, through the RCD-chain 10 is applied to the base of the transistor 1 and translates it into the open state, the current of the transistor 1 increases in time with the speed determined by the inductance of the primary winding of the transformer 3 and the value of the input constant voltage. At the initial time, the base of the transistor 13 is at zero potential, since the capacitor 18 is discharged. Due to the increase in voltage on the current sensor 12, the transistor 13 is unlocked, at the same time the collector current of the transistor 13 opens the transistor 14, which ensures the locking of the transistor t, and the polarity of the signals on the windings of the transformer 3 is reversed. The voltage surge on the collector of transistor 1 is limited by the circuit 2, Energy stored in transformer 3 during the open state of transistor 1j is output through a rectifier and provides a charge on the output capacitance of the filter 7. The voltage on the auxiliary winding 4 of transformer 3 is through resistor Iff and the diode 17 provides the charge for the capacitor 18, and the voltage at the base of the transistor 13 increases. After the switch, as the stored energy is output from the transformer, a decrease occurs.

On all of its windings, the diode 16, the capacitor 18, the capacitor 18, and the resistor 1 reopens. Since in the previous cycle the voltage is

five

ten

15

the capacitor 18 is increased, the power switch current level increases accordingly, at which it is locked, and therefore the open state and energy stored in transformer 3 increase. Thus, when the source is started, the output current and voltage are gradually increased | 1, which facilitates the operation mode of the elements and increases the reliability of the converter.

The resistor 16 eliminates the influence of the pulse noise arising from the locking of the power transistor 1 on the additional winding 4 of the transformer 20 of the mater 3, to the voltage on the capacitor 18.

After the output voltage reaches the nominal level, the error amplifier 8 is put into operation, which ensures the stabilization of the output voltage.

In the stabilization zone, when the output voltage decreases, the current through the optocoupler LED 9 decreases, the conductivity of the phototransistor of the optocoupler 9 decreases, the voltage at the base of transistor 13 and, consequently, the open state of transistor 1, as well as the power level transmitted in load. When reducing the load resistance, the action is described as negative; The connection of the detector 19, 20 15, the base of the transistor 13 is carried out positive feedback of the voltage.

In the event of a short circuit, the output current is much less than the maximum, since the voltage on the capacitor 18 in this case is zero. This provides increased reliability of the converter and improves its performance. ..

The 12-current sensor has a non-linear current-voltage characteristic, which provides an expansion of the range to allowable load currents and a decrease in the output short-circuit current.

The capacitor 24 increases the noise immunity of the converter circuit.

Thus, in a stabilized single-ended voltage converter, reliability is increased by ensuring a smooth start-up 5, as well as reducing current and thermal overloads of the elements in a short-circuit mode.

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Claims (1)

Invention Formula A stabilized single-ended DC-DC converter, and, containing a transformer with a power pn-transistor, the emitter of which is connected to the negative side of the input voltage source through a current sensor, and the collector - With a voltage surge limiter and primary winding stabilizes the output voltage of the Q transformer, the output winding Nor by reducing the current through the LED 9 of the optocoupler. The maximum current achieved at a certain load resistance value corresponds to the fully locked state of the phototransistor of the optocoupler 9 and is determined by the data of the transformer 3 windings, the values of resistors 19 and 20, and the parameters of the elements of the current sensor 12. A further decrease in the load resistance leads to a decrease in the voltage on the secondary windings, the voltage on the capacitor 18 and the base of the transistor 13, the maximum current of the power transistor 1 and the current delivered to the load decrease. Thus, through the circuit: additional winding 4 of the transformer 3, the resistor 50 55 transformer through a rectifier, and the filter is connected to an error amplifier by the output pins, the secondary winding of the transformer is connected to the base of the power transistor connected to the positive terminal of the input voltage source and connected to the circuit of the power transistor on two transistors, the control input of the Kot swarm is connected through a resistor to the phototransistor of the optocoupler, the LED of which is connected to the error amplifier, and the phototransistor of the optocoupler to the resistor voltage divider capacitor and via a diode - with Doponitelnye Transformer winding pa, wherein. 16, diode 17, capacitor 18, resistive The tori 19, 20–15, the base of the transistor 13 carries positive feedback across the voltage. With a short circuit, the output current is much less than the maximum, since the voltage on the capacitor 18 in this case is zero. This provides increased reliability of the converter and improves its performance. .. The 12-current sensor has a non-linear current-voltage characteristic, which provides an expansion of the range to allowable load currents and a decrease in the output short-circuit current. The capacitor 24 increases the noise immunity of the converter circuit. Thus, in a stabilized single-phase DC-DC converter, reliability is increased by ensuring a smooth start, as well as reducing current and thermal overloads of the elements in the short-circuit mode. Invention Formula A stabilized single-ended DC-DC converter, and, containing a transformer with a power pn-transistor, the emitter of which is connected via a current sensor to the negative terminal of the input voltage source, and the collector - With a voltage surge limiter and primary winding with 0 five transformer through a rectifier, and the filter is connected to an error amplifier by the output terminals, the secondary winding of the transformer is connected via an RCD chain to the base of the power transistor connected through a bias resistor to the positive terminal of the input voltage source and connected to the locking circuit of the power transistor on two transistors, The Kotora control input is connected through a resistor to the phototransistor of the optocoupler, the LED of which is connected to the error amplifier, and the phototransistor of the optocoupler to the resistor voltage divider, unt.irovannym capacitor and via a diode - with Doponitelnye winding transformers ra-n wherein. 5142 that, in order to increase reliability by providing a smooth start and reducing short-circuit current, a resistor is additionally inserted in it, connected in series between the additional transformer winding and the diode, and the current sensor is made in the form of a flByx bypass capacitor | series-connected resis JTOpoB and Diode, connected in series with the first resistor and parallel to the second, while in the circuit, lock the power transistor emitter first transistor. type of the conductivity of which the pp is connected to the emitter of the power transistor, the collector of the second transistor, the conductivity type of which is pp, is connected to the base of the power transistor, the base to the collector of the first transistor, and the emitter of the second transistor, phototransistor of the optocoupler and the second output The codensor is connected to the negative terminal of the input voltage source and to the common point of the auxiliary and secondary windings of the transformer.