JP3740236B2 - Flash light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light emission control circuit of a flash light emitting device, and more particularly to an improvement of a light emission control circuit that enables high-speed repeated light emission.
[0002]
[Prior art]
Conventionally, flash light emitting devices used in cameras and the like apply a voltage of several hundred volts charged to the main capacitor to the Xe tube of the light emitting means, and simultaneously apply a trigger voltage of several hundreds of volts to the trigger electrode of the Xe tube. The Xe tube is excited to emit light. However, even if the voltage of the main capacitor is low and the trigger voltage is applied, if the voltage is lower than a predetermined voltage called the light emission start voltage, light emission is impossible. This emission start voltage is determined by conditions such as the tube diameter and gas pressure of the Xe tube, and is a voltage of about 200 V in a general Xe tube used for a small camera. If the value of the light emission start voltage is high, the strobe cannot emit light until the voltage of the main capacitor becomes sufficiently high, and it takes time to charge the main capacitor, leading to inferior rapid shooting characteristics.
[0003]
As a countermeasure for this, a circuit in which a capacitor for applying a voltage for pulling the negative electrode of the Xe tube below the ground level at the start of light emission is conventionally known. This voltage doubler capacitor and an insulated gate bipolar transistor (Insulated Gate Bipolar) A circuit example using a transistor (hereinafter abbreviated as IGBT) is disclosed in Japanese Patent Application Laid-Open No. 64-17033.
[0004]
As shown in the block diagram of FIG. 6, the flash device includes a main capacitor 100 charged by a high-voltage power source (not shown), a trigger capacitor 102 charged by a power source through a resistor 101, and a high voltage Xe at the time of light emission. A trigger transformer 107 for applying to the tube 110, a thyristor 104 for trigger control, an IGBT 112 for controlling light emission, and a voltage doubler capacitor 113 for applying twice the voltage of the main capacitor 100 to both ends of the Xe tube 110 during light emission. Etc. are constituted.
[0005]
First, the main capacitor 100 is charged from a high-voltage power supply (DC-DC or the like not shown), and the trigger capacitor 102 is charged to the same voltage as the main capacitor 100 through the resistor 101 with the polarity shown. At the same time, the voltage doubler capacitor 113 is also charged to the same voltage as the main capacitor 100 via the resistor 101, the diode 103, and the resistor 115.
[0006]
During light emission, when a Hi level signal is applied to the gate of the thyristor 104, the thyristor 104 is turned on, and the charge of the trigger capacitor 102 flows through the thyristor 104 and the trigger transformer 107, and a high voltage is applied to the secondary side of the trigger transformer 107. Generated to excite the Xe tube 110. At the same time, when a Hi level signal is applied to the gate of the IGBT 112 and the IGBT 112 is turned on, the Xe tube 110 starts to emit light.
[0007]
Further, since the positive electrode of the voltage doubler capacitor 113 is grounded to the ground via the thyristor 104 during light emission, the potential of the positive electrode is 0 and the potential of the negative electrode is a negative potential. Accordingly, when the voltage of the main capacitor 100 is Vmc, the cathode potential of the Xe tube 110 is −Vmc and the anode potential is Vmc, so that a voltage twice as large as that of the main capacitor 100 is applied. Even when the voltage of 100 is low, the Xe tube 110 easily emits light. When stopping light emission, the gate of the IGBT 112 is set to Lo level to turn off the IGBT 112, and the Xe tube 110 stops light emission.
[0008]
[Problems to be solved by the invention]
However, in the above conventional example, twice the voltage of the main capacitor 100 is applied to both ends of the Xe tube 110 at the start of light emission, but the voltage of the trigger circuit that actually excites the Xe tube 110 is the same as the voltage of the main capacitor 100. In addition, when the voltage of the main capacitor 100 is low, the voltage generated on the secondary side of the trigger transformer 107 is also lowered, so that there is a problem that the Xe tube 110 cannot emit light, so-called trigger disconnection.
[0010]
  Therefore,Claim1Thru3The object of the invention described in the above is to control the trigger voltage adding means according to the voltage of the main capacitor, and supply a sufficient trigger voltage that enables the Xe tube to emit light when the voltage of the main capacitor is low, An object of the present invention is to provide a flash light emitting device that prevents the occurrence of an unnecessarily high voltage by limiting the operation of the trigger voltage adding means when the main capacitor voltage is high, and that realizes safe and stable light emission of the Xe tube.
[0018]
[Means for Solving the Problems]
  The configuration for realizing the object of the invention according to the present application is to convert electrical energy stored in the first capacitor into light as described in claim 1.Light emissionAnd a second capacitor and a coil for applying a trigger signal to the light emitting means to cause the light emissionTheIn the flash light emitting device having the trigger generating means, the voltage discriminating means for discriminating the voltage of the first capacitor, and the voltage addition for applying a voltage higher than the first capacitor to the second capacitor by using the third capacitor And an applied voltage control means for controlling the operation of the voltage adding means based on the determination result of the voltage determining means, wherein the applied voltage control means is configured such that the voltage determining means determines that the voltage of the first capacitor is predetermined. When it is determined that the voltage is lower than the value, the voltage adding means causes the second capacitor to perform an operation of applying a voltage higher than the voltage of the first capacitor, and the voltage determining means causes the voltage of the first capacitor to be applied. Is not lower than the predetermined value, the voltage adding means causes the second capacitor to have a voltage higher than the voltage of the first capacitor. The flash light emitting apparatus characterized by not perform an operation of applying a certain.
[0019]
  According to this configuration,When the voltage of the first capacitor is lower than the predetermined value, the voltage adding means is operated to charge the second capacitor with a voltage higher than the first capacitor voltage, and when the voltage of the first capacitor is not lower than the predetermined value In order to avoid generation of unnecessary high voltage, the second capacitor can be directly charged with the voltage of the first capacitor without operating the voltage adding means.
[0022]
  Other specific configurations for realizing the object of the present invention are as follows.2As described inThe voltage adding means performs an operation of applying a voltage higher than that of the first capacitor to the second capacitor by connecting the third capacitor and the second capacitor in series.Claims1In the flash light emitting device described in 1.
[0023]
  According to this configuration,FirstWhen the capacitor voltage is low,3rd capacitor and 2ndConnect capacitors in series,A voltage higher than that of the first capacitor can be applied to the second capacitor.
[0024]
  Other configurations for realizing the object of the invention according to the present application are as follows.3As described inThe voltage adding means has connection means for connecting one pole of the third capacitor to the same potential as the first capacitor, and by connecting the other pole of the third capacitor to the second capacitor, 3. The flash light emitting device according to claim 2, wherein the second capacitor is operated to apply a voltage higher than that of the first capacitor.
[0025]
  According to this configuration,The charging voltage of the second capacitor is boosted by the charging voltage of the third capacitor connected in the direction in which the negative electrode side becomes the same potential as the potential of the first capacitor, and as a result, is charged to a voltage higher than the voltage of the first capacitor. Can do.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
1 to 3 are diagrams according to a first embodiment of the present invention.
FIG. 1 is an electric circuit block diagram of a flash light emitting device according to a first embodiment of the present invention.
FIG. 2 is a timing chart of the flash light emitting device shown in FIG.
FIG. 3 is a flowchart of the operation of the flash light emitting device shown in FIG.
[0031]
In FIG. 1, reference numeral 1 denotes a known DC-DC converter, which can be controlled for charging by a CNT terminal. The power supply battery is boosted to several hundred volts and the main capacitor 2 is charged. The voltage of the main capacitor 2 is divided by the resistors 3 and 4 and detected by the microcomputer 50 that controls the operation of the entire flash device, and charging control is performed so that the main capacitor voltage is suitable for light emission.
[0032]
Reference numeral 5 denotes a PNP transistor, reference numerals 6 and 7 denote resistors, reference numeral 8 denotes an NPN transistor, reference numerals 9 and 10 denote resistors, and reference numeral 11 denotes a trigger voltage adding capacitor. Each of the elements 5 to 11 forms a trigger voltage adding circuit.
[0033]
Reference numerals 12 and 13 denote resistors, reference numeral 14 denotes an NPN transistor, and reference numerals 15 and 16 denote resistors. The elements 12 to 16 form a quick charge circuit for the trigger voltage addition capacitor 11 and the voltage doubler application capacitor 33 of the Xe tube 26.
[0034]
Reference numeral 17 is a resistor, 18 is a diode, 19 is a trigger capacitor, 20 is a resistor, 21 is a diode, 22 is a trigger transformer, and each element 17 to 22 forms a trigger circuit. 23 is a coil for limiting the light emission current, 24 is a flywheel diode that absorbs the voltage generated in the coil 23 when light emission is stopped, 25 is a diode for holding the voltage level difference between the trigger capacitor 19 and the power supply circuit, and 26 is a light emitting means. Xe tube. 28 is an IGBT which is a light emission control means, 29 and 30 are resistors, and 31 is a connection contact terminal to the camera side.
[0035]
Reference numeral 32 denotes a resistor, 33 denotes a voltage doubler capacitor for applying a voltage doubler, and 34 denotes a diode. The transistors 5 and 32 to 34 constitute a voltage doubler application circuit to the Xe tube.
[0036]
As for each terminal of the microcomputer 50, CNT is a control output terminal for charging operation of the DC-DC converter 1, and HV is an analog / digital conversion (hereinafter referred to as A / D conversion) for monitoring the voltage of the main capacitor 2. An input terminal, DV is a voltage doubler operation control output terminal, QC is a control output terminal for quick charge of the trigger voltage adding capacitor 11, and GATE is a gate control output terminal of the IGBT 28. X is an input terminal for a light emission command signal from the camera, CLK is a serial clock input terminal for serial communication, DI is a serial data input terminal, DO is a serial data output terminal, and CHG transmits whether or not the flash can emit light to the camera side. Current output terminal.
[0037]
Next, the light emission operation will be described with reference to the timing chart of FIG.
The operation at each time t0 to t2 in the flash light emitting device configured as described above will be described for each time.
[0038]
Time: t0 First, at time t0, when the power switch (not shown) is turned on, the microcomputer 50 starts its operation and monitors the voltage of the main capacitor 2 from the HV terminal. The charging operation is instructed to the DC-DC converter 1. The DC-DC converter 1 starts the boost operation, and the voltage of the main capacitor 2 rises as shown in FIG. On the other hand, the trigger voltage adding capacitor 11 is charged via the resistor 17, the diode 25, the resistor 12 and the resistor 13, and the positive potential is charged equal to the potential of the main capacitor 2.
[0039]
Time: t1 Next, when the voltage of the main capacitor 2 reaches a predetermined light emitting voltage at time t1, the fact that light can be emitted is transmitted to the camera side by the CHG terminal current.
[0040]
Time: t2 Next, when the voltage of the main capacitor 2 reaches the charge upper limit voltage at time t2, the DC-DC converter 1 is instructed to stop charging via the CNT terminal. Even if the charging of the DC-DC converter 1 is stopped, the voltage of the main capacitor 2 is lowered by the current flowing through the voltage monitoring resistors 3 and 4 and the like, so that the main capacitor voltage is lowered below a predetermined voltage. Then, the DC-DC converter 1 is started again from the CNT terminal and controlled to maintain a predetermined voltage.
[0041]
Thus, when charging is completed at time t2 and the shutter button of the camera is pressed and the X terminal is pulled down to the Lo level, the microcomputer 50 detects this and starts the light emission operation, and flash photography is performed.
[0042]
Next, the operation will be described with reference to the flowchart of FIG.
First, the main capacitor voltage is detected at the A / D input terminal HV of the microcomputer 50 (hereinafter abbreviated as a microcomputer) (S101). If the main capacitor voltage is equal to or higher than the predetermined voltage, the trigger voltage adding circuit is inoperable, so that the process branches to S104. If the main capacitor voltage is not higher than the predetermined voltage, the process is branched to S103, so that the trigger voltage adding circuit is activated. ). This is because when the main capacitor voltage is low, the trigger voltage adding circuit is operated to ensure that the Xe tube 26 emits light. However, when the main capacitor voltage is sufficiently high, the trigger voltage is grounded due to generation of an unnecessary high voltage. This is to prevent the occurrence of a trigger jump or the like in which the trigger voltage is no longer applied to the Xe tube 26 by sparking between them.
[0043]
When the DV output terminal is set to Hi level as shown in FIG. 2G in order to operate the trigger voltage adding circuit, the transistor 8 becomes conductive, and the base current of the transistor 5 is drawn through the resistor 7. Becomes conductive (S103). At this time, the emitter side of the transistor 5 is the potential on the + side of the main capacitor 2 and the collector side is also raised to substantially the same potential. Therefore, the negative pole of the trigger voltage adding capacitor 11 is raised to the same potential as the main capacitor 2. As shown by the arrow in FIG. 2E, the positive electrode potential and the positive electrode potential of the trigger capacitor 19 are 1. The potential is n times higher. This voltage can be obtained by the following equation.
[0044]
Vtrig = Vme + (C11 / C11 + C19) · Vme
Where Vtrig is the + pole voltage of the trigger capacitor C19
Vme: voltage of main capacitor 2
On the other hand, since the negative electrode of the double voltage application capacitor 33 with respect to the Xe tube is similarly raised to the anode potential of the main capacitor 2, the positive electrode of the double voltage application capacitor 33 has a potential twice the main capacitor voltage, and the anode of the Xe tube 26 is the main electrode. The potential is twice the capacitor voltage.
[0045]
Next, when the GATE output is set to Hi as shown in FIG. 2 (h), the IGBT 28 becomes conductive, and the charge of the trigger capacitor 19 flows through the diode 18, the IGBT 28, and the trigger transformer 22, A trigger voltage of several hundreds of volts is generated on the next side to excite the Xe tube 26 to start light emission (S104).
[0046]
When the light emission starts, the CHG terminal current is turned off as shown in FIG. 2B, so that the camera side detects the start of light emission of the strobe and the reflected light from the subject is emitted by an integration circuit (not shown) inside the camera. When the integration reaches a predetermined light emission amount, that is, a predetermined integration amount, the camera side sets the CLK terminal to the Hi level as shown in FIG. 2 (i) and instructs the strobe to stop the light emission. This light emission stop signal is confirmed, and if Hi level, the process branches to S107 to stop light emission, and if Lo level, the process branches to S106 (S105).
[0047]
Even if the light emission stop signal from the camera is not supplied, that is, even when the CLK terminal is at the Lo level, it is necessary to perform the light emission stop processing after a predetermined light emission time. The process proceeds to S107, and if it is within the predetermined time, the process returns to S105 and is repeated (S106).
[0048]
After a light emission stop signal (CLK terminal Hi level) from the camera is detected or when a time-out occurs, as a light emission stop process, the GATE output shown in FIG. 2 (h) is set to Lo level and the IGBT 28 is turned off to emit light. Is stopped (S107).
[0049]
When the DV terminal is set to Hi, that is, when the trigger voltage addition operation is performed, the process proceeds to S109, and when set to Lo, that is, when the trigger voltage addition operation is not performed, the process branches to S111 (S108).
[0050]
The state of the DV terminal shown in FIG. 2G is set to Lo, the trigger voltage boosting control transistor 5 is set to a non-conductive state, and the operation of the voltage adding circuit is prohibited (S109).
[0051]
Subsequently, as shown in FIG. 2 (j), the QC output is set to the Hi level for a predetermined time to turn on the transistor 14 (S110). This is because the trigger voltage adding capacitor 11 is rapidly charged to prepare for the next light emission. FIG. 2 (e) is a diagram showing a charging state of the trigger voltage adding capacitor 11, and when the transistor 14 is not turned on after the light emission is finished, the negative voltage of the trigger voltage adding capacitor 11 is the capacitance of the capacitor as shown by the dotted line in FIG. The charging is performed for a time determined by the time constants of the charging resistors 12 and 13, but when the transistor 14 is turned on, charging can be performed with a rapid time constant determined by the capacitor capacity and the charging resistor 12, as shown by the solid line in FIG. Even during high-speed repeated light emission, the trigger capacitor is sufficiently charged, and a stable light emission operation can be performed without causing light emission loss. At the same time, the voltage doubler capacitor 33 can be charged rapidly as well. Thus, the light emission operation is finished (S111).
[0052]
As described above, according to the present embodiment, the trigger voltage adding means using the voltage adding capacitor having a higher potential than the main capacitor voltage is added to the trigger circuit that is charged only to the same potential as the main capacitor 2 in the conventional example. Thus, it becomes possible to apply a stable trigger voltage to the Xe tube 26, and by using it together with a voltage doubler application circuit for the Xe tube, even if the voltage of the main capacitor is low, it prevents the light emission from being lost and stable light emission. It can be performed.
[0053]
Further, since the quick charging means for rapidly charging the trigger capacitor and the voltage doubler capacitor is provided after the light emission is completed, the Xe tube can emit light stably even in the case of high-speed repeated light emission.
[0054]
Further, by controlling the operation of the trigger voltage adding means according to the main capacitor voltage, stable light emission is maintained even when the main capacitor voltage is low, and when the main capacitor voltage is high, the operation of the trigger voltage adding means is limited. Thus, safe and reliable light emission control that does not generate unnecessary high pressure can be performed.
[0055]
Here, the operation of the trigger voltage adding means is controlled according to the voltage of the main capacitor 2. However, even when the main capacitor voltage is high, if the problem such as the trigger skipping does not occur, the trigger voltage adding means is always set. Needless to say, the operation may be performed. As a result, the control can be simplified.
[0056]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is an electric circuit block diagram of the flash light emitting device according to the second embodiment of the present invention.
[0057]
In the second embodiment shown in FIG. 4, the trigger circuit is operated at a potential higher than the voltage of the main capacitor by adding a simple circuit with the trigger voltage adding capacitor in the first embodiment. While the addition effect does not reach twice the main capacitor voltage, it is improved so that a voltage twice the main capacitor voltage can be applied to the trigger circuit.
[0058]
In FIG. 4, reference numeral 35 denotes a reverse current blocking diode at the time of trigger voltage doubler control, 36 denotes a PNP transistor for applying a trigger voltage doubler, 37 denotes a base-emitter resistance of the transistor 36, 38 denotes a base current limiting resistance of the transistor 36, and 39 denotes a first resistor. The charging resistor of the second trigger capacitor 40 is a second trigger capacitor.
[0059]
41 is an IGBT which is a trigger control means at the time of voltage doubler trigger control, 42 is a gate current limiting resistor of the IGBT, 43 is a base current limiting resistor of the transistor 45, 44 is a base-emitter resistance of the transistor 45, and 45 is a transistor 36. An NPN transistor to be controlled, 46 is an IGBT which is a trigger control means when the trigger voltage multiplier is not operated, and 47 is a gate current limiting resistor of the IGBT 46. Further, IT1 of the microcomputer 50 is a control terminal of the IGBT 46, and IT2 is a control terminal of the IGBT 41. In addition, the same code | symbol is attached | subjected to the other structure same as FIG. 1, and the overlapping description is abbreviate | omitted.
[0060]
Next, the operation will be described.
The second trigger capacitor 40 is charged from the power source 1 through the resistors 17 and 39 and the primary side of the trigger transformer 22 to the illustrated polarity. Similarly, the first trigger capacitor 19 is charged to the polarity shown in the figure via the resistor 17, the diode 35, and the trigger transformer 22.
[0061]
Subsequent operations will be described separately when the voltage of the main capacitor 2 is low and high.
[0062]
(When main capacitor voltage is low)
When the main capacitor voltage is low, the Hi level is output to the IT2 terminal to operate the trigger voltage adding means, and the IT1 terminal outputs the Lo level. As a result, the transistor 45 is turned on and the transistor 36 is also turned on. At the same time, the IGBT 41 is turned on. Therefore, the first trigger capacitor 19 -transistor 36 -second trigger transformer 40 -IGBT 41 -trigger are followed according to the path indicated by the dotted line in the figure. A current flows through the transformer 22 and a high voltage is generated on the secondary side of the trigger transformer 22. At this time, a voltage obtained by adding the first trigger capacitor 19 and the second trigger capacitor 40 in series in terms of potential is applied to the primary side voltage of the trigger transformer 22, resulting in the voltage of the main capacitor 2. A completely doubled voltage will be applied.
[0063]
Simultaneously with these trigger voltage addition operations, the transistors 8 and 5 are also turned on by the IT2 terminal to push up the potential of the voltage doubler capacitor 33, and as described in the first embodiment, between the anode and cathode of the Xe tube 26 The voltage twice that of the main capacitor 2 is applied. Further, since the GATE terminal of the microcomputer 50 is set to the Hi level, the IGBT 28 is turned on, and a strong trigger voltage by the voltage doubler trigger circuit and stable light emission are performed even when the main capacitor voltage is low.
[0064]
Subsequently, when the light emission is stopped, by setting the GATE output of the microcomputer 50 to the Lo level, the IGBT 28 is turned off, so that the current flowing through the Xe tube 26 is cut off and the light emission stops, but the Xe tube immediately after the light emission stops. Since the impedance of 26 is extremely low, about several ohms, the cathode potential of the Xe tube 26 is almost equal to the anode potential. Accordingly, the transistor 14 is turned on via the resistor 16, and as described in the first embodiment, the quick charging circuit is activated and the voltage doubler capacitor 33 is rapidly connected via the resistor 32, the resistor 12, and the transistor 14. In addition to being charged, the second trigger capacitor 40 is rapidly charged via the diode 21 and the resistor 20, and the first trigger capacitor 19 is rapidly charged via the diode 35, so that the trigger is stable even during high-speed repeated light emission. The light emitting circuit can be operated.
[0065]
(When main capacitor voltage is high)
Next, when the voltage of the main capacitor is high, the voltage doubler trigger circuit is deactivated, so that the Lo level is output to the IT2 terminal and the Hi level is output to the IT1 terminal.
[0066]
When the Hi level is output to the IT1 terminal, the IGBT 46 is turned on and the transistors 45 and 36 are turned off, so that the current is passed through the first trigger capacitor 19, the IGBT 46, and the trigger transformer 22 as shown by the one-dot chain line in the figure. A high pressure is generated on the secondary side of the flow and trigger transformer 22. At this time, only the voltage of the first trigger capacitor 19 is applied as the primary voltage of the trigger transformer, and as a result, the same voltage as that of the main capacitor 2 is applied. At the same time, since the GATE terminal of the microcomputer 50 is set to the Hi level, the IGBT 28 is turned on to emit light. Since the operation when light emission is stopped is the same as that when the main capacitor voltage is low, the description is omitted.
[0067]
According to the second embodiment, the trigger circuit is operated using a voltage twice the main capacitor voltage by adding the trigger voltage adding means capable of applying a voltage twice the main capacitor. In combination with the voltage doubler application circuit for the Xe tube, even when the voltage of the main capacitor is low, the light emission can be prevented from being lost and stable light emission can be performed.
[0068]
In addition, since a means capable of rapid charging after the end of light emission is provided, the Xe tube can be made to emit light stably even during high-speed repeated light emission.
[0069]
Further, by controlling the trigger voltage adding means in accordance with the main capacitor voltage, stable safe and reliable light emission can be performed regardless of the level of the main capacitor voltage.
[0070]
Furthermore, it is possible to perform light emission control with high response without delay when a trigger is generated.
[0071]
In the second embodiment, the operation of the trigger voltage adding means is controlled according to the voltage of the main capacitor. However, even if the voltage of the main capacitor is high, there is no need to worry about trigger skipping. Needless to say, the operation of the adding means may be performed.
[0072]
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is an electric circuit block diagram of a flash light emitting apparatus according to the third embodiment of the present invention. The third embodiment shown in FIG. 5 is a development of the second embodiment, and has a configuration in which a voltage three times that of the main capacitor can be added and applied to the trigger circuit.
[0073]
In FIG. 5, 51 is a reverse current blocking diode at the time of trigger triple voltage control, 52 is a third trigger capacitor, 53 is a PNP transistor for applying a trigger triple voltage, 54 is a base-emitter resistance of the transistor 53, and 55 is a transistor. 53 is a base current limiting resistor, and 56 is a charging resistor for the third trigger capacitor 52. In addition, the same code | symbol is attached | subjected to another structure same as FIG. 4, and the overlapping description is abbreviate | omitted.
[0074]
Next, the operation will be described.
First, the third trigger capacitor 52 is connected to the power source 1 through the primary side of the resistor 17, resistor 56, resistor 39, and trigger transformer 22, and the second trigger capacitor 40 is the resistor 17, diode 51, resistor 39, trigger transformer. The first trigger capacitor 19 is charged to the polarity shown in the figure via the resistor 17, the diodes 51 and 35, and the trigger transformer 22.
[0075]
(When main capacitor voltage is low)
When the voltage of the main capacitor from the HV terminal input is low, the Hi level is output to the IT2 terminal and the Lo level is output to the IT1 terminal in order to operate the triple voltage trigger voltage adding means. As a result, the transistor 45 is turned on, the transistors 36 and 53 are both turned on, and the IGBT 41 is turned on at the same time. Therefore, as shown by the dotted line in the figure, the first trigger capacitor 19 -transistor 36 -second trigger A current flows through the capacitor 40, the transistor 53, the third trigger capacitor 52, the IGBT 41, and the trigger transformer 22, and a high voltage is generated on the secondary side of the trigger transformer 22.
[0076]
In this case, the voltage on the primary side of the trigger transformer 22 is a voltage obtained by adding the voltages of the first trigger capacitor 19, the second trigger capacitor 40, and the third trigger capacitor 52. A voltage three times the voltage of the main capacitor 2 is applied.
[0077]
At this time, the transistors 8 and 5 are also turned on from the IT2 terminal, and a voltage twice that of the main capacitor 2 is applied between the anode and cathode of the Xe tube 26 by the voltage doubler operation as in the previous embodiment. . At the same time, since the GATE terminal of the microcomputer 50 is set to the Hi level, the IGBT 28 is turned on, and a strong trigger by the triple voltage trigger circuit and stable light emission are possible even when the main capacitor voltage is low.
[0078]
When stopping the light emission, the GATE output of the microcomputer 50 is set to Lo level and the IGBT 28 is turned off. Therefore, the current flowing through the Xe tube 26 is cut off and the light emission stops, but the impedance of the Xe tube 26 immediately after the light emission stops is several ohms. Since the cathode potential of the Xe tube 26 is substantially equal to the anode potential, the transistor 14 of the quick charging circuit is turned on via the resistor 16, and the voltage doubler capacitor 33 has a resistance similar to the previous embodiment. 32, the resistor 12 and the transistor 14 are rapidly charged. At the same time, the third trigger capacitor 52 is rapidly charged via the diode 21 and the resistor 20, the second trigger capacitor 40 is further rapidly charged via the diode 51, and the first trigger capacitor 19 is rapidly charged via the diode 35. Each voltage doubler circuit can be operated stably even during repeated light emission.
[0079]
(When main capacitor voltage is high)
Next, when the main capacitor voltage is high, the voltage doubler trigger circuit is disabled, so that the IT2 terminal outputs the Lo level and the IT1 terminal outputs the Hi level.
[0080]
Accordingly, the transistors 45, 36, and 53 are turned off, so that current flows through the first trigger capacitor 19-IGBT 46-trigger transformer 22 as shown by the one-dot chain line in the figure, and the secondary side of the trigger transformer 22 Generates high pressure. At this time, only the voltage of the first trigger capacitor 19 is applied as the primary voltage of the trigger transformer 22, and as a result, the same voltage as that of the main capacitor 2 is applied. At the same time, since the GATE terminal of the microcomputer 50 is set to the Hi level, the IGBT 28 is turned on to emit light. Since the operation when the light emission is stopped is the same as that when the main capacitor voltage is low, the description is omitted.
[0081]
Thus, according to the third embodiment, by adding the trigger voltage adding means that can apply a voltage three times that of the main capacitor, the trigger circuit is operated using a voltage that is three times that of the main capacitor. By using it together with a voltage doubler application circuit for the Xe tube 26, even when the main capacitor voltage is low, it is possible to prevent light emission from being lost and perform stable light emission.
[0082]
In addition, since the charging means that can be charged rapidly after the light emission is completed, the Xe tube can emit light stably even in the case of high-speed repeated light emission.
[0083]
Furthermore, by controlling the trigger voltage adding means according to the main capacitor voltage, stable, safe and reliable light emission can be performed regardless of the main capacitor voltage level.
[0084]
In the third embodiment, the operation of the trigger voltage adding means is controlled according to the voltage of the main capacitor. However, even if the voltage of the main capacitor is high, if a problem such as a trigger skip does not occur, the trigger is always triggered. Needless to say, the operation of the voltage adding means may be performed.
[0085]
(Correspondence between claims and embodiment)
The trigger voltage adding capacitor of the present invention refers to the capacitor 11, and the voltage adding means is the trigger voltage adding capacitor 11, the applied voltage adding circuit to the trigger capacitor 19 by the transistors 5 and 8, or the first trigger capacitor 19, and the second. This is a double pressure trigger addition circuit composed of the trigger capacitor 40 and the transistors 36, 45, or a triple pressure trigger addition circuit comprising the first to third trigger capacitors 19, 40, 52 and the transistors 53, 36, 45. It corresponds to. The trigger generating means refers to a configuration that includes the above voltage adding means and a trigger transformer to generate the trigger voltage of the Xe tube.
[0086]
The applied voltage control means of the present invention performs DV output control according to the level of the main capacitor voltage, and is configured to turn on / off the trigger voltage adding circuit by the transistors 5 and 8, or the output from the IT1 terminal or IT2 terminal. A configuration in which ON / OFF control of addition application of the trigger capacitor voltages 1 to 3 corresponds to that.
[0087]
The quick charging means of the present invention corresponds to a configuration in which the transistor 14 is turned on by a QC output to short-circuit the charging resistor, or a configuration in which the transistor 14 is turned on by the Xe tube cathode potential after light emission to short-circuit the charging resistor.
[0088]
(Other embodiments)
Up to this point, in each embodiment, the trigger voltage addition circuit, the quick charge circuit, etc. are configured by a combination of a PNP transistor and an NPN transistor. However, other switching elements such as FETs may be used, and an equivalent operation is achieved. Of course, any configuration can be used as long as it is guaranteed.
[0089]
Although the light emission amount control is not described in detail, it is needless to say that the present invention can be applied to a flash device that controls the light emission amount by flat light emission control, full light emission flash light control, or a combination of both.
[0091]
【The invention's effect】
  As explained above,Claim1Thru3According to the invention described inWhen the applied voltage control means determines that the voltage of the first capacitor is lower than the predetermined value, the voltage adding means performs an operation of applying a voltage higher than the voltage of the first capacitor to the second capacitor by the voltage adding means. When the voltage determining means determines that the voltage of the first capacitor is not lower than the predetermined value, the voltage adding means causes the second capacitor to perform an operation of applying a voltage higher than the voltage of the first capacitor. AbsentSoFirstWhen the voltage of the capacitor is low, a sufficiently high trigger voltage that enables the Xe tube to emit light is supplied.FirstWhen capacitor voltage is highIs electricBy restricting the operation of the pressure adding means, it is possible to prevent the generation of an unnecessarily high pressure and realize safe and stable light emission of the Xe tube.
[Brief description of the drawings]
FIG. 1 is an electric circuit block diagram of a flash light emitting apparatus according to a first embodiment of the present invention.
FIG. 2 is a timing chart of the flash light emitting device shown in FIG.
FIG. 3 is a flowchart of the operation of the flash light emitting device shown in FIG.
FIG. 4 is an electric circuit block diagram of a flash light emitting device according to a second embodiment of the present invention.
FIG. 5 is an electric circuit block diagram of a flash light emitting device according to a third embodiment of the present invention.
FIG. 6 is an electric circuit block diagram of a conventional flash light emitting device.
[Explanation of symbols]
1 DC-DC converter
2 Main capacitor
3, 4 Divider resistance
5, 36, 53 PNP transistor
6-9, 10, 15-17, 20, 29-32, 37, 38, 42-44, 47, 54, 55 Resistance
8,14,45 NPN transistor
11 Trigger voltage adding capacitor
12, 13, 39, 56 Charging resistance
18, 21 25 34, 35, 51 Diode
19 First trigger capacitor
22 Trigger transformer
23 Blocking coil
24 Flywheel diode
26 Xe tube
28, 41, 46 IGBT
31 Connection contact terminal
33 voltage doubler capacitor
40 Second trigger capacitor
50 Microcomputer
52 3rd trigger capacitor

Claims (3)

Trigger comprising a light emitting means for emitting light by converting electric energy stored in the first capacitor to the light, a second capacitor and a coil for applying a trigger signal to the light emitting means for causing the light-emitting A flash light emitting device comprising:
Based on voltage discrimination means for discriminating the voltage of the first capacitor, voltage addition means for applying a voltage higher than the first capacitor to the second capacitor using a third capacitor, and based on the discrimination result of the voltage discrimination means Application voltage control means for controlling the operation of the voltage addition means,
When the voltage determining unit determines that the voltage of the first capacitor is lower than a predetermined value, the applied voltage control unit is higher than the voltage of the first capacitor in the second capacitor by the voltage adding unit. When the voltage determining means determines that the voltage of the first capacitor is not lower than the predetermined value, the voltage adding means causes the second capacitor to be connected to the second capacitor. A flash light emitting device characterized by not performing an operation of applying a voltage higher than the voltage. 2. The voltage adding unit performs an operation of applying a voltage higher than that of the first capacitor to the second capacitor by connecting the third capacitor and the second capacitor in series. The flash light emitting device according to 1. The voltage adding means has connection means for connecting one pole of the third capacitor to the same potential as the first capacitor, and by connecting the other pole of the third capacitor to the second capacitor, 3. The flash light emitting device according to claim 2, wherein an operation of applying a voltage higher than that of the first capacitor to the second capacitor is performed .

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