SU817991A1 - Strong pwm signal shaper - Google Patents

Description

(54) FORMERATING POWER SCHEME SIGNAL

one

The invention relates to a pulse technique and can be used in control devices for regulators of direct current.

A device comprising a current transformer, power transistors and a starting circuit 1 is known.

A disadvantage of this device is the small steepness of the pulse fronts on the load.

There is a device containing a current transformer, two power transistors, the collectors of which are connected via a common bus through the load, the emitter of each power transistor, respectively, is connected to the power supply through the first and second windings of the current transformer, and through the corresponding third and fourth windings (the current transformer is connected to the bases this transistor 2.

The drawback of the device is the small steepness of the pulse fronts on the load.

The purpose of the invention is to increase the steepness of the pulse fronts on the load.

The goal is achieved by the fact that a device containing a current transformer has two power transistors, a collector

which, through the load, are connected to a common length, the emitter of each power transistor is connected to the power supply through the respective first and second windings of the current transformer, and through the corresponding third and fourth windings of the current transformer is connected to the base of the same transistor, five windings of the current transformer, two dis) yes, a control unit and four key transistors, with the collectors and emitters of the first and second key transistors connected to the collectors and emitters of power, respectively

5 transistors and the bases are connected respectively to the first and second outputs of the control unit, the third output of which is connected to the base of the third key transistor and through the fifth winding of the current transformer is connected to the anode of the first diode and the cathode of the second diode is connected to the collector of the third key transistor, the anode of the second diode is connected to the collector of the fourth key transistor, the base of which is connected to the common bus.

FIG. 1 shows a diagram of the driver of a powerful SHIM signal; in fig. 2 shows an embodiment of the control unit.

The former contains a current transformer 1, the windings 2 and 3 of which are connected by one output to the emitters of power transistors 4 and 5, and the second output with a power supply 6, the windings 7 and 8 of transformer 1 are connected by their leads to the base and the emitter of power transistors 4 and 5, key transistors 9 and 10 collectors and emitters are connected respectively to collectors and emitters of power transistors 4 and 5, the bases of transistors 9 and 10 are connected respectively to the terminals I and 12 of block 13, terminal 14 of which is connected to the emitter of the key transistor 16 and the winding 17 of the transformer 1 is connected to the anode of the diode 18 and the cathode of the diode 19, the collectors of transistors 4, 5, 9, and 10 are connected to the common bus, terminal 21 of the unit 13 is connected to the power bus 6.

FIG. Figure 2 shows the shapers of 22 and 23 short pulses, a divider of the frequency 24, and a modulator 25 of the pulse width.

Shaper powerful PWM signal works as follows.

When the power is turned on, one of the outputs (for example, 11) of the control unit 13 receives a trigger signal to the base of the key transistor 9, after which it is unlocked and the power supply bus 6 - winding 2 - key transistor 9 - load 20 common bus begins to flow the key transistor 9, which induces an emf in the windings of the current transformer 1 of such a sign that the power transistor 4 opens. The further open state of the transistor 4 is maintained by the current of the base winding 7. After some time from the control unit 13 and the output of the output signal 14 to the transistors 15 and 16, they open and the circuit transistors 15 and 16 - diodes 18 and 19 shorting the winding 17, which leads to the locking of the transistor 4. Both of the power transistors 4 and 5 are locked, winding 17 is short-circuited and the load 20 is disconnected from the power source. Then, the starting transistor 10 is turned on similarly, which leads to switching on the power transistor 5. Thus, transistors 4 and 5 alternately turn on and provide load connection to the power source with a duty cycle determined by the shorting width of the control unit from the turn 14.

The starting of the device is carried out with the help of short triggering pulses applied to the bases of the key transistors 9 and 10, therefore, no parasitic pulses of reverse polarity appear on the windings of the transformer 1. At the moment of switching on, the squabble transistors 9 and 10 even in the presence of a trigger signal on them. The starting transistors are loaded with a power current only until the moment when the power transistors are turned on and work for a short period of time.

Claims (2)

1.V.A. Balagurov et al. Contactless DC motors with DC , „Magnets. M., “Energie, 1975, p. 42, hey. l rice nineteen. 2. USSR author's certificate number 54Z011, cl. H 02 M 3/135, 09.05.77. TO ff / K / ij10