JPS5838920B2 - Power supply device for strobe light emitting lamp - Google Patents

Description

[Detailed description of the invention] The present invention relates to a power supply device for a strobe light emitting lamp.

A power supply device for a strobe light source oscillates an oscillator by supplying current from a DC power source such as a dry cell battery, boosts this AC output voltage using a transformer, rectifies the boosted AC, charges a capacitor, and operates the shutter button. A common configuration is to supply current from the capacitor using a switch linked to the switch to light the strobe light.In order to charge the capacitor more quickly, a voltage higher than the withstand voltage of the capacitor is supplied for quick charging. However, since this often damages the capacitor, a control circuit that monitors the voltage of the capacitor and lights up a neon tube when the voltage exceeds a certain level, thereby stopping the oscillator. A device equipped with this is disclosed in Japanese Utility Model Publication No. 48-23744.

However, in the device disclosed in this publication, even if the charging capacity of the capacitor is increased by increasing the DC voltage that is the power supply to the oscillator, the charging voltage to the capacitor remains constant, and the DC power supply The charging capacity was not fully utilized.

Therefore, an object of the present invention is to provide a strobe light emitting lamp that fully utilizes the charging capacity of a DC power supply to increase the voltage charging a capacitor as the power supply voltage increases, and prevents overvoltage charging of the capacitor. To provide power supplies for

The present invention operates an oscillator using a DC power supply, rectifies the AC voltage boosted by a step-up transformer, charges a main capacitor, and lights up a strobe light. For a power supply device for a strobe light emitting lamp, which includes a control circuit for stopping the oscillation operation of the oscillator by a gas discharge tube that has started to light up, the control circuit may be a common emitter circuit having a common resistance. , consists of a Schmitt circuit consisting of two transistors formed by a circuit connecting the collector of the first stage to the base of the next stage, one of the two poles of the gas discharge tube is connected to the charging terminal of the main capacitor, and the other is connected to the charging terminal of the main capacitor. Provided is a power supply device for a strobe light emitting lamp, which is connected to an input terminal of the control circuit and is equipped with a time constant circuit, and can increase the charging voltage to the capacitor by simply increasing the DC power supply voltage, thereby increasing the charging voltage for the capacitor during strobe photography. It is possible to increase the guide number to enhance the strobe photography ability.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a circuit diagram of a power supply device for a strobe light emitting lamp according to the present invention.

Reference numeral 1 indicates an oscillator, which includes a transistor T 3 , a primary coil N1 of a transformer T connected to the base of this transistor, a capacitor C2 connected between the oscillator coil N1 and the emitter of the transistor Tr3, and a transistor Tr3. A blocking oscillator is formed by the other primary coil N2 of the transformer T connected to the collector, and its output is boosted between one end of the secondary coil N3 of the transformer T and the emitter of the transistor Tr3. Appears as an alternating voltage.

Note that current is supplied to the transistor Tr3 from the positive side of a DC power source E such as a dry battery to the emitter and from the negative side to the collector through the coil N2 through the switch S1, and the base current is supplied through a control circuit described later.

Further, the DC power source E may have a fixed voltage or may have a variable voltage.

Reference numeral 2 indicates a discharge circuit for a strobe light emitting lamp, and the boosted alternating current voltage output from the oscillator 1 is converted into direct current via a rectifying diode D and input to the circuit 2.

The circuit 2 is provided with a main capacitor ~, one end of which is connected to the cathode of the diode D, and the other end connected to the switch S4.
is connected to the other output terminal of the oscillator 1 via the oscillator 1, so that a boosted DC voltage is applied to the main capacitor %.

A strobe light STL is connected to both ends of the main capacitor CM via a switch S4, so that it can be discharged by the charge stored in the main capacitor q.

In order to discharge the strobe light STL, a lighting circuit is provided which includes a trigger coil L having a trigger electrode, a capacitor C3, a resistor R5, and a switch S3 that discharges the charge of the capacitor C3, and the switch S3 is interlocked with the shutter button. , when the switch S3 is turned on, the charge in the capacitor C3 is discharged and a current flows through the trigger coil L.
The light emitting lamp STL lights up.

The switch S4 is a switch that can stop the current supply to the main capacitor CM, and when the current supply is stopped, the voltage waveform appearing at the cathode of the rectifying diode D becomes a half-wave pulsating current that is not smoothed. appears.

The control circuit that starts and stops the oscillation of oscillator 1 is a Schmitt circuit composed of transistors Tt□ and Tr2, and monitors the charging voltage of the main capacitor %, and lights up when the voltage exceeds a certain value. A parallel circuit of a neon tube Ne that has started to discharge and a resistor R1 and a capacitor C1 connected to the negative side of the power supply E from one end of the neon tube Ne and the base resistor of the transistor Tr1 which is the first stage of the Schmitt circuit. It consists of

As mentioned above, one end of the neon tube Ne is connected to the transistor T.
The base resistor of H is connected to one end of a parallel circuit of capacitor C1 and resistor R1, and the other end is connected to the charging terminal of main capacitor cM via resistor R5 of the strobe light STL lighting circuit. The charging voltage of cM is monitored, and when a predetermined voltage is reached, discharging is started.

First stage transistor Tr1 and next stage transistor Tr
2 and 2 have a common emitter and are connected to the negative side of the power supply E through a resistor R3, and the collector of the transistor T and the base of the transistor Tt2 are directly connected to the positive side of the power supply E through the resistor R2. is connected to form a Schott circuit.

The collector of the transistor Tr2 is connected to the base of the oscillator transistor Tr3 via a resistor R4 and a negative coil N□ to control the base current of the transistor Tr30.

In operation, when the switch S1 is closed, the transistor Tr□ is in a non-conducting state because no base current is supplied to the transistor Tr1 unless the neon tube Ne is lit.

Since the base current is supplied from the power source E through the resistor R2, the transistor Tr2 becomes conductive, and a collector current flows to make the transistor Tr3 conductive.

This causes the oscillator 1 to cause blocking oscillation.

This oscillator voltage induces a stepped-up AC voltage in the secondary coil N3 of the transformer T.

This AC voltage is exchanged to a DC voltage through a rectifier diode D, and the main capacitor is charged with DC voltage.

The voltage across this main capacitor CM is resistor R6 on the positive side.
and appears at both ends of the neon tube Ne through the switch S4, the switch S1, the power source E and the resistor R1 on the negative side.

Note that the voltage of the power supply E is applied to the neon tube Ne in addition to the voltage across the main capacitor %, but this is extremely low, and as will be explained later, the main capacitor continues to be charged for a predetermined time after the neon tube is discharged. When the neon tube discharges, the voltage drop due to the resistor R5 is large and greatly exceeds the voltage of the power source E, so it can be ignored.

When the charging voltage to capacitor CM reaches a certain voltage,
The voltage across the neon tube Ne reaches a dischargeable voltage, and the neon tube Ne discharges and lights up.

The discharge current of the neon tube flows to the capacitor C1 before flowing to the base of the first stage transistor Tr1 of the Schmitt circuit.

More specifically, since no current flows through the resistor R1 before the neon tube Ne is discharged, no potential difference appears across the resistor R1, and the capacitor C1 is in an uncharged state.

On the other hand, when the neon tube Ne discharges, a potential difference appears across the resistor R1, and the capacitor C
1 is charged.

In other words, the discharge current of the neon tube Ne is
becomes a predetermined potential (corresponding to the base potential necessary for the transistor Trl to conduct), and the capacitor C1
flows to

The time during which the capacitor C1 reaches the predetermined potential is determined depending on the discharge current of the neon tube Ne and the size of the capacitor C0.

Here, the resistor R1 is a resistor for discharging the charge of the capacitor C1.

The capacitor C1 is charged by the first stage transistor Tr1.
This continues until the base potential rises above the emitter potential.

The emitter potential is the resistor R3 because when the transistor Tt2 is conductive, its emitter current flows to the resistor R3.
has increased by the potential difference appearing across it.

Therefore, charging of the capacitor C1 continues at a potential 1 which is higher than the raised emitter potential, and when this potential is reached, a current flows to the base of the transistor Tt1 via the base resistor.

This base current makes the transistor Tr1 conductive, and a current is supplied from the positive side of the power supply E to the collector through the resistor R2, thereby lowering the base potential of the next stage transistor Tr2. Make it non-conductive at 17.

That is, charging of the capacitor C1 continues at the threshold level 1 of the Schmitt circuit consisting of the two transistors Tr1 and Tr2.

When the transistor Tr2 is made non-conductive, the base current of the transistor Tr3 of the oscillator 1 is cut off, stopping the oscillation of the oscillator 1 and preventing overcharging of the capacitor CM.

As is well known, the neon tube Ne has a hysteresis characteristic in which the discharge start voltage is higher than the discharge stop voltage, so that even if the main capacitor CM discharges and becomes lower than the predetermined voltage, When the discharge stop voltage of the neon tube Ne drops to 1, the neon tube Ne is lit.

Thereafter, when the main capacitor CM spontaneously discharges at a voltage 1 lower than the discharge stop voltage of the neon tube Ne, the discharge of the neon tube stops and the light goes out.

When the neon tube Ne stops discharging, the transistor Tr1
The base current is no longer supplied to the transistor Tr1.
is made non-conductive, and the charge on capacitor C1 is also transferred to resistor R1.
discharge through.

Due to the non-conduction of the transistor Tr□, the transistor Tr2
The base potential of increases, the transistor Tr2 becomes conductive, a base current is supplied to the transistor Tr3 of the oscillator 1, and it starts oscillating, charges the main capacitor CM with a predetermined voltage 1, and discharges or lights up the neon tube Ne. after that,
The operations described above are repeated.

Therefore, the neon tube Ne repeats blinking at regular intervals.

This point will be discussed further later.

Next, when performing a strobe operation, after confirming that the neon tube Ne is lit, the shutter button is pressed and the switch S3 is turned on.

As a result, the charge in the main capacitor CM is discharged through the light emitting lamp STL, and the light emitting lamp is turned on.

As a result, lighting or discharging of the neon tube Ne is stopped, the charge in the capacitor C1 is discharged through the resistor R1, and the transistor Tr1 becomes non-conductive.

When transistor Tr1 is made non-conductive, transistor T
The base potential of r2 rises and the transistor Tr2 becomes conductive, the oscillator 1 starts oscillating again, the main capacitor CM starts charging, and then the above-described operation is repeated.

In the present invention, as described above, even if the main capacitor CM reaches a predetermined voltage and the neon tube Ne is discharged, the operation of the oscillator 1 is not stopped immediately.

This connects a resistor R1 and a capacitor C1 to the input of a Schott circuit consisting of two transistors T r 1 and T r 2.
This is because the discharge current of the capacitor C1 and the neon tube Ne of this circuit delays reaching the threshold level.

That is, after the main capacitor CM reaches a predetermined voltage, it is possible to charge the battery in a slightly wintery manner depending on the magnitude of the discharge current of the capacitor C1 and the neon tube Ne.

Separately, consider the case where the voltage of the power source E changes.

If the power supply voltage E is increased, the transistor T r
The emitter current of 1 s T r 2 increases, and the potential difference appearing across the resistor R3, that is, the emitter voltage increases.

Therefore, when the voltage of power supply E is increased, the voltage of the power supply increases,
The threshold level of the shot circuit increases.

When the threshold level rises, capacitor C1
The longer it takes for the voltage of
The charging voltage of the main capacitor CM increases.

Conversely, when the voltage of the power supply E is lowered, the threshold level is lowered, the time for delaying stopping of the oscillator 1 is shortened, and the charging voltage of the main capacitor CM is lowered.

FIG. 2 shows a graph to clarify the charging characteristics of the device according to the invention.

In this graph, the horizontal axis represents the voltage of the power source E, and the vertical axis represents the charging voltage of the main capacitor.

Here, V b max indicates the withstand voltage of the capacitor.

vN8 indicates the lighting voltage of the neon tube.

Curve A is for the case where no control circuit is inserted, and shows that as the voltage of power source E increases, the charging voltage to the main capacitor increases, and this indicates the charging capacity of power source E's voltage.

Curve C shows the device disclosed in Japanese Utility Model Publication No. 48-23744, in which the resistor for adjusting the neon tube lighting voltage is located at a fixed position.

As is clear from the figure, in this curve C, the neon tube lighting voltage is the charging voltage to the capacitor, and even if the power supply voltage is increased, the charging voltage does not change.

Curve B shows the characteristics of the device according to the invention.

In this curve B, the line indicating the upper limit of the shaded portion is the main capacitor CM when the neon tube Ne starts discharging (i.e. lighting).
The line indicating the lower limit of the diagonal line represents the charging voltage of the main capacitor CM when the neon tube Ne stops discharging (i.e., turns off).
represents the charging voltage.

Therefore, the neon tube Ne repeats blinking as the main capacitor CM is charged and discharged.

Looking at this when the voltage of the power source E is 1, the neon tube Ne does not light up at 1 when it reaches the charging voltage Va of the main capacitor CM, and when it reaches the charging voltage Va, the neon tube lights up and charges. stop.

Thereafter, the neon tube continues to be lit until the voltage drops to the voltage vb of the main capacitor, and when the voltage vb is reached, the neon tube is turned off and charging is resumed.

After resuming charging, the neon tube has a main capacitor charging voltage of Va.
It does not turn on at 1 when it reaches 1, but it turns on only at the time of VaO.

In other words, when the main capacitor is charged, the neon tube is off at 1 when the voltage reaches Va, and when the voltage Va reaches the voltage vb.
Since the light is on while descending, it will repeatedly flash.

What is characteristic about curve B is that the charging voltage of the main capacitor CM as a whole is much higher than the voltage shown in curve C, that is, the neon tube lighting voltage vNe, and reaches a value close to curve A, which indicates the charging capacity, at 1. It is.

This is because after the neon tube Ne starts discharging, charging to the main capacitor continues for a while according to the time constant circuit, and a high charging voltage can be obtained. This is because, since the voltage across R5 is applied, even if the discharge stop voltage of the neon tube Ne is lower than the discharge start voltage, the main capacitor is recharged at the point where the voltage of the main capacitor is higher than the voltage vN8.

Therefore, the charging voltage of the device according to the invention can be maintained much higher than in conventional devices with control circuits.

Furthermore, the charging voltage of the main capacitor increases in accordance with the increase in the voltage of the power source E, and the curve B has a feature that is not seen in the curve C at all.

This is because the threshold level of the Schmitt circuit in the control circuit (which approximately corresponds to the voltage potential caused by the resistor R3) is increased by the voltage of the power supply E.

Therefore, if you increase the charging capacity by increasing the voltage of power source E,
1. The charging voltage can be increased.

Furthermore, in curve B, the slope of the line indicating the upper limit is greater than the slope of the line indicating the lower limit, and as the voltage of the power source E decreases, the interval between blinking of the neon tube Ne becomes shorter.

First, the slope of the line indicating the upper limit is not only the slope indicating a decrease in the threshold level, but also the delay in the timing of stopping charging by the time constant circuit becomes shorter as the level decreases.
It increases because a gradient indicating the degree of decrease in charging voltage is added.

On the other hand, the slope of the line indicating the lower limit is only the slope indicating a decrease in the threshold level.

Therefore, for example, when a DC power source such as a dry battery is used, it is possible to know whether the voltage of the power source E is good or bad depending on the length of the blinking interval of the neon tube Ne.

Apart from this, in the present invention, in order to check the power supply E, as shown in FIG.
A wire W is provided at the other contact point of the switch S4 provided between L and the main capacitor CM, and a switch S2 interlocked with this is connected between the end of the neon tube Ne connected to the capacitor C1 and the negative end of the power supply E. Provided between the two sides.

When the switches S2 and S4 are turned to the side opposite to that shown in FIG. 1 and the switches S1 and S3 are placed in the state shown in FIG. 1, the transistors Tr1 s Tr2 p Tr
A current is supplied to s.

Here, the base of the transistor Tr1 is directly connected to the power source E by the switch S2 and made non-conductive.

As a result, the transistor Tr2 is rendered conductive, and
The oscillator 1 oscillates and outputs a high alternating current voltage.

Since one terminal of the main capacitor CM is cut off by the switch S4, it is not smoothed, and a half-wave pulsating current is output from the cathode of the rectifier diode D, and this pulsating current is passed through the resistor R5 to the neon tube. It is given to one end of Ne.

The other end of the neon tube is connected to the other output of the oscillator 1 via the switch S2, the power supply E, the line W, and the switch S4, thereby applying the half-wave pulsating current to the neon tube Ne.

The voltage of the button power supply E is extremely low and can be ignored.

Therefore, the neon tube Ne will blink according to the oscillation frequency of the oscillator 1.

If the voltage of the power supply E drops and the oscillator 1 does not generate a voltage at a predetermined level or the oscillator does not operate, the neon tube Ne will light up for a shorter time or will not light up at all. .

Therefore, by visually observing how the neon tube lights up,
It can be used as a guide to know the voltage of the power source E, and at the same time, the circuit can be checked.

According to the present invention, the oscillation is not immediately stopped even when the neon tube is lit, but the oscillator is delayed in stopping due to the time constant circuit after the neon tube is lit and the common Ivy circuit, and the oscillation is delayed depending on the height of the power supply voltage. Since it is possible to increase the charging voltage by adjusting the charging voltage, the guide number can be increased without using an adjustment circuit.

Since no adjustment circuit is required, wiring and adjustment are easy.

Furthermore, the lighting interval of the neon tubes indicates the power supply voltage, making it easy to detect a drop in the power supply voltage.

Furthermore, a power check circuit can be easily installed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of the device according to the invention, and FIG. 2 is a graph showing the charging characteristics of the main capacitor depending on the charging capacity of the power supply voltage. 1... Oscillator, 2... Strobe light discharge circuit, E
...Power supply, NE...Neon tube, STL...Strobe light, CM...Main capacitor.

Claims (1)

[Claims] 1 It is designed to operate an oscillator using a DC power supply, rectify the AC voltage boosted by a step-up transformer, charge the main capacitor, and light the strobe light.
The power supply device for a strobe light emitting lamp includes a control circuit for stopping the oscillation operation of the oscillator by the gas discharge tube that is turned on by the charging voltage of the main capacitor. It is composed of a Schmitt circuit consisting of two transistors formed by a common emitter circuit having a resistor and a circuit in which the collector of the first stage is connected to the base of the next stage, and one of the two poles of the gas discharge tube is used to charge the main capacitor. A power supply device for a strobe light emitting lamp, which is connected to one terminal and the other end is connected to an input terminal of the control circuit including a time constant circuit.