JP2569794B2 - Inverter device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an inverter device, and more particularly to an improvement in an oscillation starting mechanism thereof.

[Prior Art] For example, an inverter device is generally used as a lighting device for lighting a halogen lamp. In particular, a self-excited inverter device is widely used because of its simple circuit configuration.

FIG. 4 shows a self-excited inverter device used for lighting a halogen lamp.

The inverter device shown in FIG. 1 includes transistors 14 and 16 connected in series to a full-wave rectifier 12 that performs full-wave rectification of an alternating current from an AC power supply 10, and capacitors 18 and 20 that are also connected in series to the full-wave rectifier 12. ,including.

Then, the emitter of the transistor 14 and the transistor 16
The series circuit of the primary windings 22a and 24a of the base transformer 22 and the step-down transformer 24 is connected between the connection point of the collector 18 and the connection point of the capacitors 18 and 20.

The base transformer 22 has two secondary windings 22b and 22c, the secondary winding 22b is connected between the base and the emitter of the transistor 14, and the secondary winding 22c is between the base and the emitter of the transistor 16. It is connected to the.

Further, a series circuit of a resistor 26 and a capacitor 28 is connected to the full-wave rectifier 12, and a starting circuit is formed such that a connection point between the resistor 26 and the capacitor 28 is connected to the base of the transistor 16 via the trigger element 30. ing.

The inverter device according to the illustrated example is configured as outlined above, and its operation will be described next.

First, when the power is turned on, the capacitor 28 is charged with electric charge via the resistor 26, and when the voltage reaches the turn-on voltage of the trigger element 30, the trigger element 30 is turned ON.

Therefore, the charge of the capacitor 28 is
Is supplied to the base of the transistor 16 and the transistor 16 is turned ON.

As a result, from the full-wave rectifier 12, the capacitor 18 → the primary winding 22a of the base transformer 22 → the primary winding 24a of the step-down transformer 24
→ Current flows through the path of transistor 16 → full-wave rectifier 12,
At this time, the transistor 16 is kept ON by the voltage generated in the secondary winding 22c of the base transformer 22, while the transistor 14 is connected to the base of the secondary winding 22c of the base transformer 22.
The reverse voltage generated at b is applied and the device is completely turned off.

Thereafter, after a certain period of time, the base transformer 22 is completely saturated, and no current flows to the base of the transistor 16, and the transistor 16 is turned off.

Then, since each voltage of the secondary windings 22b and 22c of the base transformer 22 is inverted, a current is supplied to the base of the transistor 14, the transistor 14 is turned on, and the full-wave rectifier 12 switches the transistor 14 → the primary of the step-down transformer 24. The current flows through the route of the winding 24a → the primary winding 22a of the base transformer 22 → the capacitor 20.

As described above, the transistors 41 and 16 are turned ON / OFF alternately, and as a result, a high-frequency voltage is generated in the primary winding 24a of the step-down transformer 24, and the voltage stepped down by the secondary winding 24b of the step-down transformer 24 is generated. Is supplied to a load 32 such as a halogen lamp to be turned on.

[Problems to be Solved by the Invention] However, in the conventional inverter device as described above, for example, the halogen lamp 10 becomes unlit due to life or the like and is replaced, or an ON / OFF switch is connected in series with the halogen lamp. For example, when the load 10 is turned on / off, the holding current of the trigger element 30 of the starting circuit varies, so that the current flowing through the trigger element 30 via the resistor 26 causes the trigger element 30 to be turned off. May be kept in the ON state.

As a result, the charge is no longer stored in the capacitor 20,
There arises a problem that the starting current does not flow through the base of the transistor 16 and the inverter device cannot perform regeneration oscillation.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide an inverter device that can reliably re-oscillate even when a load is replaced or ON / OFF is performed.

[Means for Solving the Problems] To achieve the above object, an inverter device according to the present invention includes a time constant circuit having a resistor and a capacitor, and a starting circuit having a trigger element. The voltage supply source for the time constant circuit and the starting circuit is supplied from a midpoint between two impedance elements connected in series to both ends of the AC power supply.

[Operation] Since the inverter device according to the present invention has the above-described means, a DC current obtained by rectifying the AC current of the AC power supply is obtained from the midpoint of the two impedance elements connected in series to both ends of the AC power supply. Can be

Then, when a direct current that draws a one-sided sine wave waveform is charged into the capacitor of the time constant circuit via the resistor and reaches the ON voltage of the trigger element of the starting circuit, the trigger element is turned ON and the inverter is started.

As described above, since the trigger element is turned ON using the DC current of one side sine wave as the voltage supply source, the trigger element always passes the zero potential, and the trigger element is turned off at that time regardless of the variation in the holding current of the trigger element. Operate.

Therefore, even when a load such as a halogen lamp is replaced, or when the load is turned on / off, it is possible to always perform stable re-oscillation of the inverter device.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a circuit configuration diagram of an inverter device according to one embodiment of the present invention, and portions corresponding to those in FIG.

A characteristic of the present invention is that the voltage supply source of the time constant circuit and the starting circuit is obtained from the midpoint of two impedance elements connected in series to both ends of the AC power supply. , Resistors 150 and 152 are connected in series to both ends of the AC power supply 110, and a resistor 126
A voltage is supplied to a time constant circuit composed of a capacitor 128 and a start circuit composed of a trigger element 130.

That is, the middle point of the resistors 150 and 152 is connected to the middle point of the capacitor 128 and the trigger element 130 via the resistor 126.

FIG. 2 shows the details of the starting circuit section shown in FIG. 1, and FIG. 3 shows an operation waveform diagram thereof.

First, a sine-wave AC current as shown in FIG. 3A is supplied from the AC power supply 110.

The sinusoidal alternating current is divided by resistors 150 and 152,
Further, since the current passes through the diode of the full-wave rectifier 112, the resistance 1
Voltages V ₁ obtained from the midpoint of 50,152 depicts a side sine wave as shown in FIG. 3 (B).

In addition, the third diagram voltages V ₁ shown in (B) is charged in the capacitor 128 through the resistor 126, and reaches the 130 turn-on voltage V _ON of the trigger device, the trigger element 130 is actuated ON.

As a result, the voltage V ₂ between resistors 126 and trigger element 130 as shown in FIG. 3 (C) becomes substantially zero for each reaches the turn-on voltage V _ON of the trigger element 130.

Then, the charge of the capacitor 128 is supplied to the transistor 116 via the trigger element 130, and the transistor 1
16 turns ON and starts inverter oscillation.

Here, if the load of the halogen lamp or the like in FIG.
When the 132 is replaced due to its life, etc., or when a switch or the like is connected in series with the load and turned on / off, the third
Voltages V ₁ shown in FIG. (B) passes through the always zero potential because it is a supply voltage to the capacitor 128, the trigger element 130
At this time, the trigger element 130 is turned off without being affected by the variation of the holding current.

Therefore, a stable starting current is always supplied to transistor 11
6 can be supplied.

[Effect of the Invention] As described above, according to the inverter device of the present invention, the voltage supply sources of the time constant circuit and the starting circuit are obtained from the midpoint of the two impedance elements connected in series to both ends of the AC power supply. Therefore, the trigger element can be turned off without being affected by the variation of the holding current, and a stable starting current can always be supplied to the inverter.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an inverter device according to one embodiment of the present invention, FIG. 2 is a main circuit configuration diagram of the inverter device shown in FIG. 1, and FIG. 3 is an inverter device shown in FIG. FIG. 4 is a circuit configuration diagram of a conventional inverter device. 10,110 AC power supply 12,112 Full-wave rectifier 26,126 Resistance (time constant circuit) 28,128 Capacitor (time constant circuit) 30,130 Trigger element (start-up circuit) 150,152 Resistance (impedance element)

Claims (1)

(57) [Claims] An inverter device having a rectifier circuit for rectifying an AC current supplied from an AC power supply and converting the rectified current to a high-frequency current by turning on / off a transistor, a time constant circuit having a resistor and a capacitor, An activation circuit having a trigger element connected to the midpoint between the resistance and the capacitor of the time constant circuit, and supplying an activation voltage to the transistor when the capacitor voltage becomes a constant value, comprising: And a voltage supply source for the starting circuit is obtained from a midpoint between two impedance elements connected in series to both ends of the AC power supply.