JPS594477Y2 - Constant voltage charging device for strobe capacitors - Google Patents

Description

[Detailed description of the invention] The present invention reduces unnecessary consumption of the power source and reduces the consumption of relay contacts in a strobe device that uses high-voltage dry batteries or a DC power source derived from pulsating current as a power source. This invention relates to a constant voltage charging device for strobe capacitors that can extend the life of the strobe.

Figure 1 shows a conventional constant-voltage charging device for strobe capacitors. B1 is a high-voltage power source consisting of a high-voltage dry battery or a DC power source derived from pulsating current, B2 is a low-voltage power source consisting of a low-voltage dry battery, etc., and S B2 is a power switch that opens and closes in conjunction with each other, C1 is a strobe capacitor, R
□~R5 is a resistor, ZD is a Zener diode, TR1,
TR2 is a transistor, Ry is a relay R, and Ryb is a relay R.
It is a normally closed contact of y.

Now, when the power switches S□ and B2 are turned on, a charging current flows from the power source B0 to the capacitor C0, and charging starts.

When capacitor C1 completes charging, the voltage at point a increases, Zener diode ZD becomes conductive, and transistor TR
1, TR2 turns on.

Therefore, relay Ry operates to turn off its contact Ryb and stop charging capacitor C0.

When a strobe (not shown) emits light in this state, capacitor C1 is discharged, and the voltage at point a decreases, causing Zener diode ZD to become non-conductive, transistors TR1 and TR2 to turn off, and relay Ry to turn off as well. become.

Therefore, the contact Ryb of the relay Ry is turned on again, and the above operation is repeated.

However, in such conventional devices, relay Ry continues to be energized while charging of capacitor C1 is stopped, which increases the power consumption of low-voltage power source B2, resulting in increased battery consumption and , when charging begins to capacitor C1 after the strobe fires, a large charging current flows even though the relay contact Ryb is not completely closed, which causes a lot of wear and tear on the relay contact Ryb, shortening its life and many other problems. There were drawbacks.

The present invention improves these conventional shortcomings and provides a constant voltage charging device for smartphones and robots that reduces power consumption of the device, reduces battery consumption, and reduces relay contact consumption. It is something.

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

FIG. 2 is a circuit diagram showing an embodiment of the present invention, and the same parts as in the conventional example shown in FIG. 1 are given the same reference numerals.

TR1 to TR3 are transistors, r1 to r5 are resistors, 5
SS1, 5SS2 are bidirectional two-terminal thyristors, C2,
C3 is a capacitor, T1 is the primary winding of a pulse transformer,
T2 is the secondary winding of the pulse transformer, and these and the
Low-voltage power supply B2, which is also in the conventional example shown in the figure. Power switch S2.
By resistors R1, R2 and Zener diode ZD,
It comprises a continuity control circuit that generates a trigger pulse to turn on the three-terminal thyristor SCR, and a relay control circuit that temporarily operates the relay Ry that opens and closes the relay contact Ryb.

A charging circuit is formed by interposing a three-terminal thyristor SCR and a relay contact Ryb in series between the power source B1 and the strobe capacitor C1.

Next, the operation will be explained. When the relay Ry is not activated, its contact Ryb is in the on state as shown in the figure, and a voltage is applied between the anode and cathode of the three-terminal thyristor SCR, but when the power switch S1. When S2 is on, the three-terminal thyristor SCR is off, so the capacitor C1 is not charged, the Zener diode ZD is also non-conducting, and the transistor TR1
, TR3 is also turned off.

Therefore, the transistor TR2 is forward biased by the power supply B2 and turned on, thereby maintaining a substantially short-circuited state between both terminals of the capacitor C2.

On the other hand, since the transistor TR3 is off, the capacitor C3 starts charging by the power supply B2 via the resistor r5.

After a certain period of time has elapsed, when the capacitor C3 is charged to a predetermined value, the bidirectional two-terminal thyristor 5SS2 is turned on, and the discharge current of the capacitor C3 flows through the primary winding T1 of the pulse transformer.

Therefore, a trigger pulse is generated in the secondary winding T2 of the pulse transformer, and this pulse causes the three-terminal thyristor SC to
Trigger R to turn it on.

When the 3-terminal thyristor SCR turns on, the capacitor C
1 starts charging.

Then, when the capacitor C1 is charged to a predetermined value, a
The voltage at the point increases and the Zener diode ZD becomes conductive, so that the transistors TR1 and TR are turned on.

When the transistor TR3 is turned on, the capacitor C3 is substantially short-circuited and is therefore held in an uncharged state.

Further, when the transistor TR1 is turned on, the transistor TR2 is turned off, so that the short-circuited state of the capacitor C2 is released.

Therefore, capacitor C2 starts charging via resistor r4.

After a certain period of time has elapsed, when capacitor C2 is charged to a predetermined value, bidirectional two-terminal thyristor 5SSl is turned on, and relay Ry is temporarily energized by the discharge current of capacitor C2, and relay RY operates to Contact Ry
Turn b off.

When the contact Ryb of the relay Ry is turned off, the three-terminal thyristor SCR is turned off and stops charging the capacitor C1 because the voltage applied between the anode and the cathode disappears.

If the transistors TR1 and TR3 that die in this state continue to be on, the capacitor C3 will not be charged, so the primary winding T1 of the pulse transformer will not be energized, and therefore a pulse will also be generated in the secondary winding T2. Without, 3-terminal thyristor S
CR is held in an off state, and charging to capacitor C1 is also held stopped.

If a strobe (not shown) fires in this condition,
Since the charge in the capacitor C1 is discharged, the voltage at point a decreases, and the Zener diode ZD becomes non-conductive.
The above operation is repeated with transistors TR1 and TR3 turned off.

FIG. 3 shows another embodiment of the present invention, in which the power source B2, resistor r5, capacitor C2, bidirectional two-terminal thyristor 5SS2, etc. of the embodiment shown in FIG. 2 are omitted.

Next, the operation will be explained. When the power switch S1 is on, the three-terminal thyristor SCR is off, so the capacitor C1 is not charged.

However, capacitor C2 starts charging via resistor r4.

Furthermore, in this state, the transistors TR1 and TR3 are off, so a bias current flows between the base and emitter of the transistor TR2 via the resistor r3.

On the other hand, since the bidirectional two-terminal thyristor 5SS1 is off, the collector current of the transistor TR2 does not flow, and the lower square of the primary winding of the pulse transformer is not energized, so the three-terminal thyristor SCR maintains the off state.

After a certain period of time has passed, when the capacitor C2 is charged to a predetermined value, the bidirectional two-terminal thyristor 5SS1 is turned on, and current flows between the collector and emitter of the transistor TR2, energizing the primary winding T1 of the pulse transformer. be done.

Therefore, a trigger pulse is generated in the secondary winding T2 of the pulse transformer, and this pulse causes the three-terminal thyristor SC to
R is triggered on and begins charging capacitor C1.

At this time, since the transistor TR3 remains off, the relay Ry is not energized, and the contact Ryb of the relay remains on.

After that, when capacitor C1 is charged to a predetermined value, the voltage at point a increases and Zener diode ZD becomes conductive, so transistor TR1 is turned on and transistor T
The base and emitter of R2 are maintained in a substantially short-circuited state to keep transistor TR2 in an off state, and current is applied between the base and emitter of transistor TR3 to forward bias it.

Then, when the capacitor C2 is charged to a predetermined value after a certain period of time has elapsed, the two-way two-terminal cyrisk SSS,
When turned on, transistor TR3 turns on and causes collector current to flow, temporarily activating relay Ry.

When the relay Ry operates, its contact Ryb turns off, so the three-terminal thyristor SCR turns off and stops charging the capacitor C1.

While the transistor TR1 remains on, the pulse transformer primary winding T1 is not energized, so the three-terminal thyristor SCR remains off.
Charging to the capacitor C1 also remains stopped.

Next, when the strobe emits light, the capacitor C1 is discharged, so the voltage at point a decreases, transistors TR1 to TR3 are turned off, and the above operation is repeated.

FIG. 4 shows the transistor T in the embodiment shown in FIG.
This is an example in which R3 is omitted, and only the main parts are shown.

This means that between the winding impedance ZR of a normal relay and the winding impedance ZP of a pulse transformer, ZR>
This method takes advantage of the fact that the relationship ZP holds true, and as explained above in the embodiment of FIG.
2 is charged to a predetermined value, and the bidirectional two-terminal thyristor 5
When SS1 is turned on, since the relationship ZR>ZP is established as described above, current flows through the primary winding T0 of the pulse transformer to the collector and emitter of the transistor TR2, and the relay Ry turns on. No such current flows.

If the transistor TR2 is off, current flows only through the relay Ry, and the relay Ry operates.The other operations are the same as those in the embodiment shown in FIG. 3, so a description thereof will be omitted.

FIG. 5 is a diagram showing the main parts when a normally open contact is used as the contact of the relay Ry in the embodiment shown in FIGS. It is connected in parallel to the anode and cathode of the SCR, and even if this is done, when the relay Ry is not activated, its contact Rya is off and voltage is applied between the anode and cathode of the 3-terminal thyristor SCR. Yes, only when relay Ry operates, contact Rya turns on, shorting the anode and cathode of the 3-terminal thyristor SCR and eliminating the applied voltage, so it works almost the same as in the above embodiment. It is something.

FIG. 6 shows the transistor TR3 in the embodiment of FIG.
This shows a part of an embodiment in which the transistors TR1 and TR2 are replaced with a three-terminal thyristor 5CR2, and the other transistors TR1 and TR2 may be replaced with two-terminal thyristors in the same manner.

As described above for each embodiment, according to the present invention, when the strobe capacitor C1 is fully charged,
Since the relay is no longer constantly energized, power consumption is reduced, unnecessary battery consumption is prevented, and the relay contacts are completely closed or opened (in the case of the embodiment shown in Figure 5). Since charging of the capacitor starts in this state, the relay contacts are prevented from being unnecessarily worn out, which has the effect of extending the life of the relay.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional example, Figs. 2 and 3 are circuit diagrams each showing an embodiment of the present invention, and Figs. 4 to 6 each show a part of a modified embodiment of the present invention. There is a circuit diagram. B1...High voltage power supply, B2...Low voltage power supply, Sl, B2...Power switch, SCR...
...3-terminal thyristor, C1... Strobe capacitor, TR1-TR3... Transistor, 5SS1, 5SS2... Bidirectional 2-terminal thyristor, ZD...・・Zener diode, Ry・
... Relay, Ryb ... Normally closed contact of relay, T1 ... Primary winding of pulse transformer, T2
...Secondary winding of a pulse transformer.

Claims (1)

[Scope of utility model registration request] A charging circuit is formed by interposing a 3-terminal thyristor and a relay contact between the power source and the strobe capacitor, and the 3-terminal thyristor is turned on after a certain period of time has passed after the power is turned on and the terminal voltage of the strobe capacitor decreases. a conduction control circuit that generates a trigger pulse to set the strobe light to a predetermined value, and a relay control circuit that temporarily operates a relay that opens and closes the relay contact when a certain period of time elapses after the strobe capacitor is charged to a predetermined value. , the above rule
When inactive, the relay contact is in a state of applying voltage between the anode and cathode of the three-terminal thyristor,
When a trigger pulse is generated by the conduction control circuit, this three-terminal thyristor is turned on, and the power supply voltage is applied to the strobe capacitor to charge it. When charging of the strobe capacitor is completed, after a certain period of time has elapsed, the thyristor is turned on. The relay control circuit operates the relay so that its contacts temporarily eliminate the voltage applied between the anode and cathode of the three-terminal thyristor, thereby turning off the three-terminal thyristor. A constant voltage charging device for strobe capacitors.