JPS59117823A - Transistor switching driving circuit - Google Patents

Abstract

PURPOSE:To reduce the power of a DC power supply and to attain switching drive of a transistor(TR) to be driven effectively by constituting the titled circuit by a pulse transformer, a current transformer, two diodes and two TRs. CONSTITUTION:The circuit consists of the pulse transformer 23 having a primary winding N9, two secondary windings N10, N11, the current transformer 24 having a primary winding N12 and a secondary winding N13, the two TRs 21, 22, two diodes 25, 26, two resistors 27, 28 and a pulse generating circuit 20. Thus, since the base current when the TR29 to be driven is turned on is supplemented by feeding back positively the collector current and the loss of the base storage charge when the TR29 to be driven is turned off is performed by the TR22 turned on with an exciting current flowing to the secondary winding N11 of the transformer 23, the power consumption of the DC power supply is decreased and the circuit constitution is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Description of the technical field to which the invention pertains) The present invention relates to a transistor switching drive circuit, particularly a D
The present invention relates to a switching drive circuit for transistors used in O-DO converters and the like.

(Description of Prior Art) A conventional transistor switching drive circuit of this type is composed of a transistor 2, a diode 3, a transformer 4, and a resistor 5, as shown in FIG. Reference number 1 indicates a pulse generating circuit, reference number 6 indicates a driven transistor, and reference symbol E indicates a DC power supply voltage.

When the output generated by the pulse generation circuit 1 reaches a high level, the transistor 2 turns on, and the first
- A DC power supply voltage r is supplied to the secondary winding N1 with the polarity shown in FIG. 1, and a voltage is induced in the secondary winding N3 of the pulse transformer 4 with the polarity shown in FIG. Due to the induced voltage between the resistor 5 and the base of the transistor 6, a current is flows in the direction shown in FIG. 1 through the resistor 5, and the transistor 6 is turned on.

Next, when the output of the pulse generating circuit 1 becomes low level, the transistor 2 is turned off. At this time, excitation energy is stored in the K pulse transformer 4, and this excitation current flows through the secondary winding N3 in the opposite direction to the direction of the current i3 in FIG. disappears, and transistor 6 is turned off. Thereafter, the excitation energy of the pulse transformer 4 is extinguished by feeding back the excitation current from the secondary winding N2 through the diode 3 to the DC power supply until the transistor 2 is turned on next time.

Transistor 6 is turned on by turning transistor 2 on and off at a certain period.

Off-driven switching.

In FIG. 1, a large capacity transistor 6 is generally used, and the transistor 6 is used in a saturated state when turned on. Therefore, when the transistor 6 is on, the base current of the transistor 6 needs to have a considerable current value. Therefore, when transistor 2 is turned off, the base charge of transistor 6 increases, but transistor 6
In order to increase the switching-off speed, that is, to shorten the storage time, the excitation energy of the transformer 4 when the transistor 2 is turned off is increased to increase the current flowing through the secondary winding N, as shown in FIG. It is necessary to increase the excitation current flowing in the direction opposite to the direction of is.

In such a conventional configuration, when transistor 2 is on, it is necessary to supply from the DC power source a base current sufficient to turn on transistor 6 and sufficiently saturate it, and sufficient excitation energy to shorten the storage time of transistor 6. However, this had the drawback that the power consumption of the DC power supply was large and a DC power supply with a large capacity was required.

Next, the circuit shown in FIG. 2, which shows another example of the conventional transistor switching drive circuit of this type, will be briefly described.

This example includes two pulse generators 7, 8, two transistors 9, 10, a pulse transformer 11, a current transformer 12, two diodes 13, 14, and four resistors 15. ，
16, 17 and 18. Transistor 19 is the driven transistor.

When the transistor 9 is turned on by the pulse generating circuit 7, a voltage is induced in the secondary winding mN 6 of the pulse transformer 11 with the polarity shown in FIG. 2, and the transistor 19 is turned on. At this time, the current i6 in the secondary winding N flows through the diode 13. It is supplied from the DC power supply voltage E through the resistor 15. When transistor 19 is turned on, the primary winding N7 of current transformer 12
The collector current of the transistor 19 flowing through the transistor 19 is fed back from the secondary winding N6 of the current transformer 12 through the diode 14 to the primary winding N4 of the pulse transformer 11, and the base current necessary to sufficiently saturate the transistor 19 is immediately fed back to the primary winding N4 of the pulse transformer 11. Current will be supplied from the current transformer 12.

Next, the pulse generation circuit 7 turns off the transistor 9, and at the same time, the pulse generation circuit 8 turns on the transistor 10, and the current flowing through the secondary winding N8, which is the collector feedback current of the transistor 19, passes through the diode 14.
Furthermore, the current from the DC power supply voltage F is passed through the diode 13. the second winding N of the pulse transformer 11 through the resistor 15;
flows to The secondary winding N6 of the pulse transformer 11 includes the sum of these currents, the second-order winding N, and the secondary winding N.

A current determined by the turns ratio of the current i6 flows in the direction opposite to the direction of the current i6 in FIG. 2, the charge accumulated in the base of the transistor 19 disappears, and the transistor 19 is turned off.

After this, when the transistor 10 is turned on, a voltage from the DC power source is applied to the secondary winding N of the pulse transformer 11 with a polarity opposite to that shown in FIG. Therefore, the pulse width from the pulse generating circuit 8 should be set so that the pulse transformer 11 is not biased and saturated.

In such a conventional configuration, the power consumption of the DC power supply can be reduced, but the disadvantage is that the circuit becomes complicated because an off-drive circuit consisting of the pulse generation circuit 8 and the transistor 10 is required. Ta.

(Detailed Description of the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks and provide a transistor switching drive circuit with a simple configuration that can effectively drive switching of a driven transistor while using less power from a DC power source. It is in.

(Structure of the Invention) The circuit of the present invention is a transistor switching drive circuit that switches and drives an NPN (PNP) type output transistor. a second secondary winding, and one end of each of the secondary windings is commonly connected to the emitter of the output transistor so that voltage pulses induced in each of the six secondary windings are added. a first transformer of the NPN (PNP) type, the base, emitter and collector each being connected to the other end different from the common end of the second secondary winding, the emitter of the output transistor and the base of the output transistor; a first diode having a cathode (anode) and an anode (cathode) respectively connected to the base of the output transistor and the other end different from the common end of the second winding; a second transformer connected to the emitter of the output transistor and having a primary winding connected so as to positively feed back at least a portion of the collector current of the output transistor to the output transistor via the secondary winding; The present invention is characterized in that a cathode (anode) and an anode (cathode) each include a second diode connected to the base of the output transistor and the other end of the secondary winding of the second transformer.

(Detailed Description of the Invention) Next, embodiments of the invention will be described in detail with reference to the drawings.

FIG. 3 shows a first embodiment of the present invention, in which a primary winding mNo and two secondary windings Is N to , Nt +
a current transformer 24 having a negative winding N12 and a secondary winding N,3; two transistors 21.22; two diodes 25.26; It is composed of resistors 27 and 28 and a nozzle generating circuit 20. Reference number 29 is a driven transistor.

Next, the operation will be explained.

Now, when the output of the pulse generation circuit 20 is at a high level, the transistor 21 is on, and at this time,
The excitation current of the pulse transformer 23 gradually increases, and then the excitation current value as seen from the primary winding mNo when the transistor 21 is turned off is calculated. Then, the value of 1° can be suppressed to below the value of E/'r, where r is the resistance value of the resistor 27 and r is the DC power supply voltage.

Next, the output of the pulse generation circuit 20 goes to low level,
The transistor 21 is turned off, and a voltage having a polarity opposite to the "f" polarity shown in FIG. 3 is induced in each winding of the pulse transformer 23.
The exciting current of the pulse transformer 23 is supplied to the next winding N,. The voltage is supplied to the base of the transistor 29 through the diode 25, and the transistor 29 is turned on. At this time the next winding N,. The value of the current iso flowing through the . Ha-next volume lol No
, the second winding N,. , if the number of turns of the second secondary winding N11 is n9+nlO+ n11, then I +o=
It is expressed as Ig X nO/nlo.

When the transistor 29 is turned on and the collector current of the transistor 29 flows, this current flows to the negative secondary winding N12 of the current transformer 24, and from the secondary winding N, the collector current of the transistor 29 is positively fed back to the base through the diode 26. The transistor 29 is immediately sufficiently saturated. In this way, even after the transistor 29 is switched on, the next winding M N s continues. The excitation current from continues to flow,
The current i1° will gradually decrease.

Next, the current i when the transistor 21 is turned on.

, the value of . '. Next, the pulse generation circuit 20
When the output becomes high level, the transistor 21 is turned on and a voltage appears in each winding of the pulse transformer 23 with the polarity shown in FIG. Second secondary winding N11 in case B
Let the voltage of the second secondary winding N1. be Vl,'. The value lll1 of i+t flowing from to the base of the transistor 22 is I
++'=((E Vu'xng/no)/r-I
+. 'X neo/n9 ) X no/nn, transistor 22 is turned on, transistor 29
The feedback current of the collector current flows through the diode 26 to the transistor 22, and at the same time, the base accumulated charge of the driven transistor 29 is also discharged through the transistor 22, and the transistor 29 is turned off.

Even after the transistor 29 is turned off, the transistor 21 continues to be turned on, and the excitation current of the pulse transformer 23 gradually increases.As explained at the beginning, when the transistor 21 is then turned off, this excitation current causes the transistor 29 to turn on again. Started on. In this way, the transistor 29 can be turned off and on by turning on and off the transistor 29 at a certain period using the output of the pulse generating circuit 20.

A current value generator for turning on the transistor 29 according to the above explanation;
. 1l-t, a current value sufficient to operate the positive feedback circuit composed of the current transformer 24, the diode 26, and the transistor 29 is required, and this is satisfied with a sufficiently high current value. Also, the current value for starting the transistor 29 is 1.
' is the feedback DC flowing through the diode 26 and the transistor 2
A base current value of the transistor 22 is required to be determined in order to cause a current to discharge the base accumulated charge of 9 to flow through the transistor 22, and this is also satisfied with a sufficiently high current value. Furthermore, the transistor 22 may have a sufficiently smaller capacitance than the driven transistor 29, and may have a very low collector breakdown voltage, so a transistor that is much faster than the driven transistor 29 can be used.

FIG. 4 shows a second embodiment of the present invention, and this embodiment includes a pulse generation circuit 30, two transistors 31 and 32,
It is composed of a pulse transformer 33, a current transformer 34, two diodes 35, 36, and two resistors 37, 38. Reference number 39 is a driven transistor.

In contrast to the first embodiment shown in FIG. 3 in which an NPN type driven transistor 29 is driven by switching, this embodiment drives a PNP type driven transistor 39 by switching. be. As the driven transistor 39 becomes a PNP type,
The transistor 32 is also a PNP type, and the diode 3
5 and 36 are opposite to those in the first embodiment, and the second winding N1. The difference from FIG. 3 is that the winding direction of the second secondary winding N, 6 is the same as the winding direction of the primary winding m N + 4, but the operation of the circuit is the same as that of the first embodiment described above. Since they are the same, they will be omitted.0 In the first embodiment and the second embodiment, the second secondary winding N1°, the second secondary winding N1H and the second secondary winding in the pulse transformers 23 and 33, respectively. Line N1. An embodiment in which the winding direction of the second secondary winding N H6 and the second secondary winding N H6 is the same as the winding direction of the negative winding N, and opposite to the winding direction of the primary winding N + 4 is easily conceivable. . In the embodiment modified in this way, when the output of the pulse generating circuit 20 or 3o becomes high level, the driven transistor 29 or 39 is turned on, respectively, and the output of the pulse generating circuit 20 or 3o turns on.
Alternatively, the second embodiment differs from the first embodiment and the second embodiment only in that when the output of 30 goes low, the two driven transistors or 39 are turned off, and the other operations are the same.

Further, in all the embodiments described above, embodiments in which the transistors 21 or 31 or the transistors corresponding to these transistors are replaced with P N'P type transistors can also be easily considered.

Furthermore, in all of the embodiments described above, resistor 28 or 38 is replaced by driven transistor 29 or 3.
When 9 is turned off, an excessive voltage is applied to the secondary winding N+3 or N
These resistors or the resistors equivalent to these resistors can be replaced with a series circuit of a Zener diode and a diode or a series circuit of a Zener diode, a diode, and a resistor. Other embodiments are also easily conceivable.

(Detailed Description of the Invention) According to the present invention, by employing the above configuration, the pace current when the driven transistor is turned on is positively fed back based on the collector current, and the driven transistor is charged. Since the loss of base accumulated charge when the base is turned off is achieved by a transistor that is turned on by the excitation current flowing through the second secondary winding of the first transformer, the power consumption of the DC power supply is reduced and the circuit configuration is simple. It can be done.

[Brief explanation of the drawing]

1 and 2 each show a conventional column, and FIGS. 3 and 4 each show an embodiment of the present invention. 1.7, 8, 20.30...Pulse generation circuit,
2.9, 10, 21, 22, 31. 32...Transistor, 3, 13, 14, 25, 26, 35° 36
・・・・・・Diode, 4, 11, 23. 33・Old・
・Pulse transformer, 5, 15, 16, 17, 18°27.
28,37.38...Resistor, 6,19°29
．． 39... Driven transistor, 12. ．． 24゜34...Current transformer, N,,N,...
Primary winding, N2. N, ...secondary winding,
N,,N,,N8. N... N18...Secondary winding, N7. N,, N,2
．． N,,, N,,...-Next winding, N, o,
N,, mountain... the next winding, N,... N13... Second secondary winding, 13+ 16+ 1
10+ IIIoooo. No.! Concave #2 Shi1

Claims (1)

[Claims] In a transistor switching drive circuit for switching and driving an NPN (PNP) type output transistor, a primary winding, a second winding, and a second secondary winding are input with pulses for performing the switching drive. a first transformer having a winding, one end of each of the secondary windings being commonly connected to the emitter of the output transistor so that voltage pulses induced in each of the six secondary windings are summed; and an NPN (PNP) type transistor whose base, emitter and collector are respectively connected to the other end different from the common end of the second secondary winding, the emitter of the output transistor and the base of the output transistor, and a cathode. a first diode (anode) and an anode (cathode) respectively connected to the base of the output transistor and the other end different from the common end of the second winding; a second transformer connected to the emitter and having a primary winding connected so as to positively feed back at least a portion of the collector current of the output transistor to the output transistor via the secondary winding; and a cathode (anode). and a second diode, each having an anode (cathode) connected to the base of the output transistor and the other end of the secondary winding of the second transformer.