JPS6051476A - One-transistor type inverter - Google Patents

Abstract

PURPOSE:To reduce the switching loss by bypassing a base current while the voltage between the collector and the emitter of a main transistor crosses zero after the voltage of a base returning winding is inverted to positive. CONSTITUTION:A transistor 51 is connected to the base of a main transistor 32 of a base feedback 1-transistor type blocking inverter 3 for firing a discharge lamp 4, the output of a base feedback winding 31b is differentiated by a capacitor 53, applied to the base of the transistor 51, the transistor 51 is turned ON while the voltage between the collector and the emitter crosses zero immediately before the base current is supplied to the transistor 32, thereby bypassing the base current of the transistor 32. Accordingly, before crossing zero, the transistor 32 is prevented from being turned ON to reduce the switching loss, thereby improving the circuit efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a single-stone inverter used, for example, in a discharge lamp lighting device.

(Background of the Invention) FIG. 1 shows a circuit configuration of a discharge lamp lighting device using a conventional base feedback type single-stone inverter. In the same figure, 1
is an AC power source such as a commercial power source, a rectifier such as a full-wave rectifier circuit 2 is connected to this AC power source 1, and a single-stone blocking oscillation type transistor inverter 3 is connected between the rectifier output terminals a and f+ of this rectifier circuit 2. Furthermore, a discharge lamp 4 as a load is connected to the secondary winding 31s of the output transformer 31 of the inverter 3.

The inverter 3 includes an output lance 31 and a main transistor 32, and the output lance 31 is connected between the positive output terminal a of the rectifier circuit 2 and the collector of the transistor 32.
This primary winding 31 is connected to the primary winding 31p of
A resonant sensor 33 is connected in parallel with p, and the emitter of the transistor 32 is connected to the rectifier circuit 2 via a diode 34.
A diode 35 is connected to the negative output terminal 1) of the transistor 32 and the diode 34 between the collector of the transistor 32 and the negative output terminal of the rectifier [1 path 2]. ! Connect the base feedback winding 31h of the output transformer 31 to the rectifier 11.
] Connect to the 0 side output terminal of path 1 and 2 (I!7
ON is connected to the bases of the transistors 32 through an oscillator circuit consisting of a capacitor 36, an inductor 37, and the like.

Note that the diode 34 is based on 1 to transistor 32.
-6 in order to protect against emitter reverse voltage leakage and supply just enough base extraction current.

Furthermore, when the transistor 32 is off, the die A--de 35 is
It is a damper diode that provides a current path in the opposite direction to the collector current of the transistor 32 to the primary winding M311) of the output transformer 31 to prevent distortion of the output waveform.

Next, we will describe the operation of the discharge lamp lighting device constructed as described above.

Alternating current'? When the Fi source 1 is turned on, the full-wave rectifier circuit 2 generates a full-wave rectified output (pulsating output), which is sent to the inverter 3 as L12. As a result, in the inverter 3, the rectified output is passed through the bias resistor 38 to the transistor 32.
is applied as a base current, and the transistor 32 is turned on. Hereinafter, 1 to transistor 32 will be referred to as transistor 32.
] Primary winding 31D of lefter output transformer 31 - Base return winding 31b - Capacitor 36 - Inductor 37 -
Collector-base positive feedback consisting of transistor 320 base etc.? The loop oscillates due to the inductance of the primary winding 3ip and the resonance of the second winding 33, and each winding 31ρ of the output 1 to the lance 31.

3? S, sih Ni Takashu et11 power J11 le. Run I 41. t.

This high frequency output is applied via the secondary winding old S of the output transformer 31 to turn on the light.

By the way, in this inverter 3, the capacitor 36
By supplying base current to the transistor 32 through the series circuit of the inductor 37 and the inductor 37, the high frequency switching characteristics are improved. 7, the capacitor 36 and the inductor 37 constitute a series resonant circuit, and the positive direction current provides sufficient drive to the 1-transistor 32, and the negative direction current performs a large pace charge extraction, and this base extraction current is , due to the action of the diode 34, that is, at the moment of turn-off of the main transistor, the main 1~
When the collector current of the transistor 32 becomes equal to the base extraction current, the diode 34 is turned off, thereby preventing stoppage and excess/deficiency. However, people like this/ll! b main 1 to lan register 3 in il no
2 switching ports or thought culm 1 (not reduced).

(Object of the Invention) An object of the present invention is to further reduce the switching [1 step] of a base feedback type IUi blocking inverter, thereby improving the inverter circuit efficiency and the reliability f1 of the main transistor.

(Structure of the invention) Ministry of the Invention, etc. 1. :1 As a result of various studies on the causes of this, we found that the voltage between the rector and the emitter of the transistor 32 was
Ce is 1! Even if it is a positive interval before I
ii Since the 3ψ winding voltage becomes zero and becomes a positive voltage, the section where the base voltage of the transistor 320 becomes positive (1-ji, in this section C is 1 to 3)
2 turns on even before the base current flows and the VCO crosses zero, and as a result, the energy of the resonant circuit of the capacitor 33 and the output transformer primary winding 3ip is transferred to the transistor 32. It will be consumed at ]・
The present invention was achieved based on the knowledge that the switching loss when the transistor 2 is turned on increases.

The present invention has a base return jW type 1 which has an output transformer and drives the main transistor with a base current supplied from the base return of the output transformer through a capacitor.
In the stone transistor inverter, the base current of the main transistor is bypassed until the collector-emitter voltage of the main transistor crosses zero after the base feedback winding voltage is positively reversed with respect to the off state of the main transistor. A switching element is provided between the base and emitter of the main transistor.

Here, the term "base-emitter" refers to diodes, resistors, and inductors that are connected in series with the base or emitter of the main transistor, as well as cases in which each terminal of a switching element is directly connected to the base and emitter of the main transistor. , including cases where indirect connection is made through circuit elements such as content 1.C.
There is.

(Explanation of Examples) Embodiments of the present invention will be explained below using the drawings.

In addition, the corresponding part is represented by ?US in l1J-.

FIG. 3 shows a circuit configuration of a discharge lamp lighting device according to an embodiment of the present invention. LO The H position in the same figure is different from that in FIG. - A transistor 51 is connected.

<iOh, die A-152 [11~Unjista 32]
Similar to the diode 34, this is used to protect the transistor 51 from jφ electric current between the base and the transmitter.

Next, the operation of the device N shown in FIG. 3 will be explained with reference to the voltage and current waveform diagrams at various parts shown in FIG.

When the AC power supply 1 is turned on, a full-wave rectifier output (pulsating output) is generated from the full-wave rectifier circuit 2, which is applied to the inverter 3, which causes the inverter 3 to oscillate as described above, generating a high-frequency output. The lamp 4 lights up.

However, in this inverter 3, the base winding 31
By differentiating the output voltage of the transistor 53 with the capacitor 53 and applying it to the base of the transistor 32, the output voltage of the transistor 32 is changed from just before the base current 1b is supplied to the transistor 32. From 1 to zero crossing of R month 2 to the period in which the output voltage of the base winding 31b is positive even though the collector-emitter voltage of the transistor 32 is positive (including (1) (t2)) the transistor 51 Turn on 1!, 1 to base current r of transistor 32
b is bypassed. As a result, the transistor 32
] The base current is supplied and turned on only in the section ([3) after the rector-emitter voltage VCe crosses zero, and the switching loss is reduced.

FIG. 5 shows a partial circuit diagram of a single-stone inverter according to another embodiment of the present invention. The inverter shown in the same figure is connected in series (
1 river! base feedback winding 3.
If a winding terminal is provided at 11) and the bases of transistors 1 to 55 are connected to this terminal, the collectors and emitters of transistors 1 to 55 are connected to 1). i6.
57] is connected in parallel with Nden 9-36.53.

With this configuration, the zener diode 5
) 4 to J: 1 to operating point of transistor 51, that is, 1
~A section where the base current of the transistor 32 is bypassed (
12) in FIG. 4 can be more strictly limited, and it is possible to prevent the bypass section 12 from being too large or too small for the section IFil 1. In addition, when the transistor 32 is turned off and the base feedback winding voltage becomes negative, the 21-den-1 no reset circuit composed of the transistor 55, the diode 56, 57, etc. Nibi 5
3 is discharged and reset, thereby reducing the Q of the oscillator circuit by connecting a discharging resistor in parallel with the transistors 36 and 53, and deterioration of the switching characteristics of the transistor 32 and 51 or the capacitor. This prevents the waveforms of various parts from shifting from the proper timing due to residual charge at 36°53.

Note that the present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within the scope of the spirit of the present invention. For example, by directly connecting the emitters of the transistors 1 to 32 and 51 described above, the diode 3
Either 4 or 52 may be omitted. Also, depending on the operating conditions, the resistor 58 may be connected in parallel with the capacitor 36, or if the on-voltage between the base and emitter of the transistor 51 can be used as a threshold, the Zener diode 54 may be replaced with a resistor. can. Furthermore, a part of the output is rectified and stored in a capacitor, and the rectifier circuit 2
When using a so-called power feedback type inverter which supplies the inverter 3 as auxiliary power while the rectified output of the capacitor is lower than the voltage across the capacitor, the diode 35 may be omitted.

As described above, according to the present invention, the base current to the main transistor is bypassed and the main transistor is not turned on until the voltage between the collector and emitter of the inverter transistor crosses zero. The switching loss is improved, and therefore the circuit efficiency and the reliability of the main transistor (II) can be improved.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional 17 (i-type discharge lamp lighting device) using an inverter, Fig. 2 is a pressure or current waveform diagram of each part of the discharge lamp lighting device of Fig. 1, and Fig. 3 is 1 of the present invention
161 is a circuit diagram of the discharge lamp lighting device according to the embodiment; FIG. FIG. 2 is a circuit diagram of the Gandengen lighting device according to the invention. 1...AC power supply, 2...full wave rectifier circuit, 3...
Inverter, 31... Output Lance, 311)...
・Base return line, 32...output 1 to transistor,
36...1 inductor, 37...inductor, 51
...1-Ran resistor. 11- Figure 3 Figure 4・) φ Star Street Voltage 415 O t2 t3 Toku3do 42 doors 2^ 81 1 / Figure 5 6 473-

Claims (1)

[Claims] An output 1 to a lance having a primary winding and a feedback winding;
A base feedback single-stone blocking inverter, comprising a main transistor for energizing a secondary winding, and a base of the main transistor is driven by a current supplied from the feedback winding through the main transistor. Return 3! for the state where the I transistor is off!
i! A switching element is provided between the base and emitter of the main transistor to bypass the base current of the main transistor after the voltage of the winding is reversed to positive until the voltage between the collector and emitter of the main transistor is reversed to negative. This is a one-stone inverter with a unique feature.