SU1201983A1 - D.c.voltage converter - Google Patents

Abstract

CONSTANT VOLTAGE CONVERTER, containing two reverse transducer shunted by reverse diodes, one of the power electrodes of which are connected to the first input power supply terminal, and the other are connected to the corresponding cones of the limiting chokes, the midpoint of which is connected to the output output, C CO filter, A switch path shaping unit for control transistors, characterized in that, in order to simplify the circuit and improve the weight and size parameters, the block for traversing the path li ne regulating transistor connected between the middle point restrictive throttle and the first power input terminal and configured as a parallel-connected transistors, the input of which is connected to the control unit, and a capacitor.

Description

The invention relates to electrical engineering and can be used in key controllers and a constant voltage stabilizer.

The aim of the invention is to simplify the scheme, improve the weight and size parameters.

Fig. 1 is a circuit diagram of a voltage converter; in fig. 2 - diagrams of control voltages.

The voltage converter contains a power source 1, two control transistors 2 and 3, each shunted by reverse-offset diodes 4 and 5, the collectors of transistors are connected to the first output of the power source I, and the emitters to the ends of the limiting throttle 6 with the same half windings 7 and 8, device 9 formation, consisting of parallel-connected additional transistor 10 and capacitor 11 and connected between the midpoint of the throttle 6 and the first output of the power source 1, the LCD filter 12 is filled on the diode 13, the condensation The torus 14 and the choke 15 and the connecting point of the limiting throttle 6 with the second output of the power source, the control circuit 16, the load 17, is located at the output of the LCD filter 12. The voltage converter operates as follows.

At time t, the control transistors 2 and 3 and the auxiliary transistor 10 of the shaping circuit 9 are closed, the diodes 4 and 5 are biased in the opposite direction, the capacitor J 1 of the shaping circuit 9 is charged to a voltage close to the supply source 1 with polarity, In brackets shown in Fig. 1, the energy that is charged in the choke 15 of the filter 12 is transmitted through the open diode 13 to the load 17 and the capacitor 14.

The transistor 2 is turned on at the moment tj by the action of the unlocking signal Un arriving at its base almost without loss due to the presence of throttles 6, to the half winding 8 of which the total voltage of the power supply source 1 1 is applied {due to the inertia of the I2 filter 13 . At the same time, the discharge of the capacitor 11 of the device 9 through a transistor

832

2 and the half-winding 8 drops 6. As the capacitance 1I rises, the blocking bias on diode 5 decreases. When capacitor II discharges completely, diode 5 becomes conductive, and in a closed circuit: half-windings 8 and 7 droplets 6, diode 5 - transistor 2 - begins to circulate current due to the energy transferred to drosel 6 during discharge of capacitor 11 forming device 9. After the diode 13 of the circulating filter 12 is locked, the energy stored in the inductor 6 during the dissipation time of the volume charge in the diode 13 is additionally supported. Thus, the locking of the diode 13 of the filter 12 and the discharge of the capacitor 11 of the forming device 9 occur simultaneously, which virtually eliminates from the cycle of operation, the stage of preparation of the capacitor 11, as a result of which the speed of the converter increases.

With a small load current 17, the diode I3 of the filter 12 can close before the moment of full discharge of the capacitor 11, which also contributes to an increase in the speed of the voltage converter.

At the moment t-, the base of transistor 2 receives a blocking signal - Uy and the base of transistor 10 of the forming device 9 is the unlocking signal u2. Since the turn-off time of high-quality silicon transistors, the main part of which is the resorption time, is significantly longer than their turn-on time, the turning on of the transistor 10 of the device 9 formation at the time t occurs at voltage

(one)

UB., (UTI - Ug5) / 2,

close to zero. The turn off of transistor 2 takes place after the resorption phase during voltage

(2)

and, 2Ur, + and

35

significantly lower voltage supply source 1. Moreover, both the turning on of the transistor 10 and the turning off of the transistor 2 occur at voltages, which follows from expressions (1) and (2), which are not dependent on the voltage of the power source I, but are determined by the operating mode and parameters of the converter elements zh- neither Expressions (1) and (2) are valid while neglecting the active resistance of the semi-windings 7 and 8 of the throttles 6 where the following notation is used: UT; U, g is the voltage drop across the collector-emitter junction of saturated transistors 2 and 10, respectively; Ua5 is the direct voltage drop across the diode 5. of the transistor 10 at the moment of locking t is accompanied by the charging of the discharged capacitor 11 of the device 9 by forming a half-winding current 7 dross 6 and a load current 17. With an appropriate choice of the capacitor 1I capacitance value during the turn-off time of the transistor will not have time to noticeably increase, therefore, the loss to turn off will be small. The charge of the capacitor II stops when the diode 13 of the filter I2 is unlocked, and the voltage on the capacitor 11 is fixed at the level of the supply voltage 1 audio, and the energy of the choke 6 is returned to the power source 1. At the moment t, under the action of the post-transistor 3 of the πiping to the base Ui.ci, its starting signal occurs, Tsz is unlocked with almost no loss due to the presence of 6 droplets, the full voltage of source I is applied to the winding 7 of which for the time of dissipation of the volume charge nutrition At the same time, the discharge of the capacitor 11 of the device 9 through the transistor 3 and the winding 7 of the throttle 6 begins. As the capacitor 11 is discharged, the blocking bias on the diode 4 decreases. When the capacitor 11 is completely discharged, the diode 4 becomes conductive, and in a closed circuit: half windings 7 and 8 throttles 6, diode 4, transistor 3 begins to circulate current due to the energy transferred by the choke f during the discharge of capacitor 11 forming device 9. After the diode I3 of the circulating filter 12 is locked, the energy stored in the inductor 6 during the dissipation of the volume charge in the diode 13 is additionally maintained. At the moment tg, the blocking signal U (..j and device 9) goes to the base of transistor 3 formation - unlocking The transistor turning on the signal Uu2 10 at the moment tg occurs at the voltage defined by the expression CO and the switching off of the transistor 3 - at the voltage defined by the expression (2), where instead of U; 11 it is necessary to substitute the values Uf., Urt4 respectively. Further percents Switching switches of transistors 2, 3 and 10 are repeated as described above. Thus, neither turning on nor turning off transistors 2, 3 and 1O is accompanied by the release of high power dynamic losses, and the exclusion of restrictive throttles 6 from the circuit interrupting the load current does not cause high-frequency overvoltage peaks at the moments when regulating transistors 2 and 3 are closed. In addition, the operation of the voltage converter eliminates the time interval for the removal of excess energy from the throttle 6, which ensures its speed. This inclusion of the shaping device 9 makes it possible to reduce the required number of restrictive chokes and capacitors, as a result of which the weight and dimensions of the voltage converter are reduced.

Claims (1)

A DC / DC converter containing two regulating transistors shunted by reverse diodes, one of the power electrodes of which is connected to the first input power output, and the other is connected to the corresponding ends of the limiting choke, the middle point of which is connected to the output terminal, an LCD filter, block for forming a switching path of regulating transistors, characterized in that, in order to simplify the circuit and improving overall dimensions, a block for generating switching paths control transistors is connected between the midpoint of the limiting inductor and the first input power output and is made in the form of parallel-connected transistor, the input of which is connected to the control unit, and a capacitor, ® SU „„ 1201983 Fig /