Abstract:
The present invention relates to an IPL apparatus that is used as a hair removing machine or cures skin ailments by periodically irradiating Xenon lamp light on the user&#39;s skin, the IPL apparatus comprises: a double-voltage unit which has a double-voltage capacitor, and outputs a high voltage by superposing an inputted supply voltage with a voltage charged in the double-voltage capacitor; a charging capacitor which charges energy for turning on a Xenon lamp by accumulating electric charges supplied from the double-voltage unit; a reference voltage generator which sets a charging voltage level charged in the charging capacitor; and a switch unit which is positioned between the double-voltage unit and the charging capacitor, and switches on and off the movement of the electric charges to the charging capacitor from the double-voltage unit by setting an output of the reference voltage generator to a control signal.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an intense pulsed light apparatus capable of controlling an energy level with an SCR, and more specifically, to an intense pulse light apparatus having a Xenon flash driving circuit capable of controlling a voltage controlling-type energy level with an SCR without employing a noise filter and a high-power output voltage-controlled constant voltage power supply circuit. 
       BACKGROUND ART 
       [0002]    In the initial stage, many laser apparatuses were introduced to treat skin ailments. These laser apparatuses are appropriate for curing a particular skin ailment by selecting the laser light of a wavelength necessary for treating specific ailments and locally irradiating the selected laser light on the corresponding skin part to be treated. However, said laser apparatuses have a lot of side effects, and particularly, it is hard to irradiate laser beams on the skin that has various skin ailments. That is to say, because each ailment needs proper laser beams, these ailments should be treated by using several laser beams if the patient wants to be treated due to the freckles or blemishes, the expanded blood vessels, and fine wrinkles or large pores on his or her face. 
         [0003]    To solve such drawbacks, an intense pulsed light (hereinafter, IPL) apparatus, which simply cures various skin ailments by irradiating diverse wavelengths of lights at a time, has been developed by an American doctor Bitter, and is being widely used at the moment. The IPL apparatus employs a lamp flash that emits light having a wavelength of 350 nm to 1200 nm, and adjusts the wavelength of the emitted light with a filter, and generally, as the irradiation lamp, a Xenon lamp irradiates laser beams on the skin for three seconds, two to three times approximately. 
         [0004]    Like mentioned above, when the IPL apparatus irradiates laser beams with the Xenon lamp, the amount of energy that is irradiated at a time should be controlled at a desired level. Further, the IPL apparatus has to supply regular power to a Xenon flash circuit in order to emit the irradiation energy of which the level is determined. For the lamp flash driving circuit of the IPL apparatus, a PAM (Pulse Amplitude Modulation) driving circuit mode, a PWM (Pulse Width Modulation) driving circuit mode, and a mixed type thereof are used. 
         [0005]      FIG. 1  is a driving circuit diagram of a prior IPL apparatus that employs a PAM driving mode. Power supplied from a supply voltage  10  ranging from 100V to 240V is inputted to an output voltage-controlled constant voltage supplier  30  (for example, SMPS (Switching Mode Power Supply)) after noise has been removed by a noise filter  20 . The output voltage-controlled constant voltage supplier  30  converts the inputted power into stable DC power, and supplies the DC power to a capacitor  80 . When the user adjusts the irradiation energy of a Xenon lamp through a user interface  60 , a corresponding adjustment signal is inputted to a controller  50 , and the controller  50  precisely adjusts an output voltage of the output voltage-controlled constant voltage supplier  30  according to the adjustment signal. Further, if the controller  50  drives a Xenon lamp flash unit  40  through a trigger  70  at every proper time by using the energy supplied to the capacitor  80  from the output voltage-controlled constant voltage supplier  30 , the energy stored in the capacitor  80  is instantly supplied to the Xenon lamp flash unit  40 . Hence, if a voltage applied to the capacitor  80  is adjusted, a desired level of the energy supplied to the Xenon lamp flash unit  40  is obtained. In the PAM driving mode of  FIG. 1 , the amount of energy (that is, voltage values on both ends of the capacitor  80 ) supplied to the Xenon lamp flash unit  40  is adjusted in such a manner that the amount of energy delivered to the user&#39;s skin can be controlled precisely. 
         [0006]      FIG. 2  is a driving circuit diagram of a prior IPL apparatus that employs a PWM driving mode. Power supplied from a supply voltage  10  ranging from 100V to 240V is inputted to an output voltage-controlled constant voltage supplier  30  (for example, SMPS (Switching Mode Power Supply)) after noise has been removed by a noise filter  20 . The output voltage-controlled constant voltage supplier  30  converts the inputted power into stable DC power, and supplies the DC power to a capacitor  80 . When the user adjusts the irradiation energy of a Xenon lamp through a user interface  60 , a corresponding adjustment signal is inputted to a controller  50 , and the controller  50  outputs a trigger signal for performing a proper PWM driving process to a trigger  70 , and precisely controls the amount of energy supplied to the Xenon lamp flash unit  40 . In this case, the controller  50  may adjust a charging voltage by transmitting a control signal even to the output voltage-controlled constant voltage supplier  30  when necessary.  FIG. 3  is a graph for illustrating the amount of energy charged and discharged in accordance with time in the Xenon lamp flash unit  40  of the prior IPL apparatus that employs the PWM driving mode shown in  FIG. 2 . Like illustrated in  FIG. 3 , it could be understood that the Xenon lamp flash unit  40  is driven only in the oblique sections from the moment when a trigger signal is applied, while the energy is charged to the trigger time Tt from time 0. That is to say, in the PWM driving mode of  FIG. 2 , by controlling the width and intervals of the oblique time for the amount of energy supplied to the Xenon lamp flash unit  40 , it is possible to precisely adjust the amount of energy delivered to the user&#39;s skin. 
         [0007]    However, the prior IPL apparatus that employs the PAM driving mode in  FIG. 1 , the prior IPL apparatus that employs the PWM driving mode in  FIG. 2 , and the prior IPL apparatus that employs the mixed type thereof use the output voltage-controlled constant voltage supplier  30  in order to supply stable power to the capacitor  80 . In this case, because the IPL is characterized in that DC current values outputted from the output voltage-controlled constant voltage supplier  30  use hundreds of milliamperes (mA) to tens of amperes (A), a high-capacity power source should be switched, whereby a high-priced output voltage-controlled constant voltage supplier  30  is essential. Further, it is problematic because an expensive noise filter  20  has to be equipped in order to remove noise of the power that is supplied to the high-capacity output voltage-controlled constant voltage supplier  30 . Such a problem is now emerging since the more expensive noise filter  20  and the higher-priced output voltage-controlled constant voltage supplier  30  should be used if the capacitor  80  has to be charged at a faster speed in order to more often turn on the Xenon lamp flash unit  40  at every second. 
         [0008]    In addition, when the output of the IPL apparatus is increased, the IPL apparatus may be used as a hair removing machine for removing hairs on legs, arms and the like. However, if the IPL apparatus is used as the hair removing machine, a higher output is necessary. Thus, when the driving circuit of the prior IPL apparatus is used, the higher-priced output voltage-controlled constant voltage supplier ( 30 ) and the more expensive noise filter ( 20 ) should be provided as well. 
       DISCLOSURE OF THE INVENTION 
     Technical Problem 
       [0009]    To solve such problems, it is therefore an object of the present invention to provide an IPL apparatus capable of controlling an energy level with an SCR, which can stably provide power to a Xenon lamp flash unit even by supplying power to a capacitor without an output voltage-controlled constant voltage supplier. 
         [0010]    In addition, it is another object of the present invention to provide an IPL apparatus capable of controlling an energy level with an SCR, which can be equipped with a driving circuit for stably increasing an output voltage of the IPL apparatus within a relatively short time even in an area having a power voltage ranging from 100V to 120V, which is deficient to obtain high energy, or if there is a change owing to an unstable voltage of the inputted power. 
       Solution to Problem 
       [0011]    To achieve the above purpose of the present invention, in an IPL apparatus that is used as a hair removing machine or cures skin ailments by periodically irradiating Xenon lamp light on the user&#39;s skin, the IPL apparatus comprises: a double-voltage unit which has a double-voltage capacitor, and outputs a high voltage by superposing an inputted supply voltage with a voltage charged in the double-voltage capacitor; a charging capacitor which charges energy for turning on a Xenon lamp by accumulating electric charges supplied from the double-voltage unit; a reference voltage generator which sets a charging voltage level charged in the charging capacitor; and a switch unit which is positioned between the double-voltage unit and the charging capacitor, and switches on and off the movement of the electric charges to the charging capacitor from the double-voltage unit by setting an output of the reference voltage generator to a control signal. 
         [0012]    Desirably, it is better to provide, in front of the reference voltage generator, a constant current supply unit for supplying a regular current to the reference voltage generator. 
         [0013]    In order to supply more stable DC power to the controller, it is better to further comprise a constant voltage supplier for inputting power outputted from the noise filter and supplying the power to the controller, but the constant voltage supplier used in the present invention is to stably supply power to the controller. Thus, the constant voltage supplier having small capacities, that is, roughly tens of watts, may be accepted in such a manner the driving circuit of the Xenon lamp flash unit can be designed at a low price. 
         [0014]    Driving circuit of the Xenon lamp flash unit according to the present invention can be driven PAM (Pulse Amplitude Modulation) mode by controlling reference voltage or PWM (Pulse Width Modulation) mode by adjusting the interval of trigger signal using controller. 
       Advantageous Effects 
       [0015]    According to the present invention, the IPL apparatus enables a stable IPL apparatus driving function even through an inexpensive circuit configuration, which can accumulate electric charges in the capacitor without a high-power output voltage-controlled constant voltage power supplier and exactly sense a voltage applied to the capacitor, so that the corresponding voltage may reach a regular value, and can radiate the desired energy by controlling discharge time or supplying a desired voltage to the Xenon lamp flash unit. Further, according to the present invention, the IPL apparatus is easily implemented in PAM and PWM driving modes through the same circuit configuration. 
         [0016]    Besides, according to the present invention, since the IPL apparatus employs a double-voltage unit, the IPL apparatus smoothly drives the Xenon lamp flash unit by receiving sufficient energy within a relatively short time irrespective of an area, where a voltage value of a supply voltage is unstable or a low supply voltage ranging from 100V to 120V is used. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 2  is a driving circuit diagram of a prior IPL apparatus that employs a PWM driving mode. 
           [0018]      FIG. 3  is a graph for illustrating the amount of energy charged and discharged in accordance with time in a Xenon lamp flash unit of the prior IPL apparatus that employs the PWM driving mode shown in  FIG. 2 . 
           [0019]      FIG. 4  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. 
           [0020]      FIG. 5  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. 
           [0021]      FIG. 6  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. 
           [0022]      FIG. 7  is a graph for illustrating the amount of energy charged and discharged in a charging capacitor in accordance with time. 
           [0023]      FIG. 8  is a waveform diagram for illustrating that an input wave timing unit outputs an input wave timing signal by using an input wave inputted from a noise filter unit. 
           [0024]      FIG. 9  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. 
           [0025]      FIG. 10  is a partial circuit of  FIG. 9 , and shows a circuit diagram for illustrating double voltages. 
           [0026]      FIG. 11  is a graph for illustrating a characteristic of voltage to current operation of a Zener diode. 
           [0027]      FIG. 12  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. 
           [0028]      FIG. 13  is a partial circuit of  FIG. 12 , and shows a circuit diagram for illustrating double voltages. 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
       [0000]    
       
         
           
               10 : SUPPLY VOLTAGE 
               20 : NOISE FILTER UNIT 
               30 : OUTPUT VOLTAGE-CONTROLLED CONSTANT VOLTAGE SUPPLIER 
               35 : CONSTANT VOLTAGE SUPPLY UNIT 
               38 : CONSTANT CURRENT SUPPLY UNIT 
               40 : XENON LAMP FLASH UNIT 
               50 : CONTROLLER 
               60 : USER INTERFACE UNIT 
               70 : TRIGGER UNIT 
               80 : CHARGING CAPACITOR 
               90 : REFERENCE VOLTAGE GENERATOR 
               91 : RECTIFICATION UNIT 
               93 : SMOOTHING UNIT 
               95 : VOLTAGE DIVIDER 
               97 : ANALOT TO DIGITAL CONVERTER 
               110 : DOUBLE-VOLTAGE UNIT 
               115 : INPUT WAVE TIMING UNIT 
               125 : ZENER TEMPERATURE COMPENSATION CIRCUIT UNIT 
               195 : VOLTAGE DIVIDER 
           
         
       
     
       DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0048]    Hereinafter, the advantages, the features, and the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0049]      FIG. 4  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. According to the present invention, the IPL apparatus comprises a noise filter unit  20 , a double-voltage unit  110 , a switch unit  120 , a charging capacitor  80 , a reference voltage generator  90 , a controller  50 , a user interface unit  60 , a trigger unit  70  and a Xenon lamp flash unit  40 . 
         [0050]    Additionally, the present invention may further comprise a rectification unit  91 , a smoothing unit  93 , a constant voltage supply unit  35 , and a constant current supply unit  38 . 
         [0051]    The noise filter unit  20  is a circuit element for removing noise from an inputted supply voltage  10  ranging from 100V to 240V, and an output of the noise filter unit  20  passes through the rectification unit  91  and the smoothing unit  93  and supplies to the double-voltage unit  110 . The rectification unit  91  and the smoothing unit  93  are partially contributed to form double-voltage as will be described later on  FIG. 10 . It is needless to say that the output of the noise filter  20  is supplied to the double-voltage unit  110  in a circuit where the rectification unit  91  and the smoothing unit  93  are not equipped. The double-voltage unit  110  is a circuit for outputting the inputted supply voltage after increasing a peak value of the supply voltage double times or more. The switch unit  120  is turned on and off according to an output signal of the reference voltage generator  90 , and charges the charging capacitor  80 . The reference voltage generator  90  is a circuit for setting one of various levels of reference voltages, and the user interface unit  60  is configured as an operating switch or the like and used to input IPL output power from the user. 
         [0052]    The controller  50  adjusts a reference voltage of the reference voltage generator  90  according to a control signal outputted from the user interface unit  60 , and generates a trigger signal at proper timing. The trigger unit  70  controls the radiation of a Xenon lamp into on and off operation by outputting a trigger operation signal for triggering the Xenon lamp flash unit  40  according to the trigger signal inputted from the controller  50 , and the Xenon lamp flash unit  40  irradiates Xenon light on the user&#39;s skin according to the trigger operation signal. Further, the output of the noise filter  20  is used to supply stable power to the controller  50  via the constant voltage supplier  35 . Generally, since the controller  50  uses a low operating voltage of 5V, it is possible to use the low-priced constant voltage supplier  35  having tens of watts, and thus it is even possible to use the inexpensive low-capacity noise filter  20  that removes noise from power supplied to the constant voltage supplier  35 . 
         [0053]    From now on, a circuit operation shown in  FIG. 4  will be described. When  FIG. 4  is described, a circuit that comprises a rectification unit  91 , a smoothing unit  93 , a constant current supply unit  38 , and a constant voltage supply unit  35 , which are selectively equipped, will be described as follows. 
         [0054]    If the user inputs an output level through the user interface unit  60 , a voltage level of the reference voltage generator  90  is set via the controller  50 . 
         [0055]    The inputted supply voltage  10  is supplied to the rectification unit  91 , the constant current supply unit  38 , and the constant voltage supply unit  35  after noise has been removed in the noise filter unit  20 . The power inputted to the rectification unit is rectified into a DC component, is superposed with an AC component in the smoothing unit  93 , and is provided to the double-voltage unit  110 . The power from which noise is removed is inputted to the constant current supply unit  38 , and a constant current is outputted to the reference voltage generator  90 . After said noise-removed power has been inputted to the constant voltage supply unit  35 , stable power is supplied to the controller  50 . 
         [0056]    The double-voltage unit  110  which has received the smoothed power outputs a peak value of the supply voltage double times or more, and the switch unit  120  compares the voltage inputted from the double-voltage unit  110 , the voltage inputted to the reference voltage generator  90 , and a voltage of an output end (input end of the charging capacitor). If a certain condition is satisfied, the switch unit is converted into the “on” state to charge the charging capacitor  80 . The controller  50  generates a trigger signal by calculating proper timing. The trigger unit  70  outputs a trigger operation signal for triggering the Xenon lamp flash unit  40  according to the trigger signal inputted from the controller  50 , and the Xenon lamp flash unit  40  irradiates Xenon light on the user&#39;s skin according to the trigger operation signal. 
         [0057]    Meanwhile, in the circuit diagram of  FIG. 4 , it is illustrated that an input-blocking switch SW is added to the noise filter unit  20 , and that a control signal for turning on and off a switch of the noise filter unit  20  is received from the controller  50 . Said configuration will be described as follows. If the noise filter unit  20  which is not added with the switch is used, the energy is irregularly charged even when the charged energy is discharged to the Xenon lamp flash unit  40 , thereby causing a problem that the energy supplied to the user&#39;s skin is not regular. Such a problem will be described in reference to  FIG. 7 .  FIG. 7  is a graph for illustrating the amount of energy charged and discharged in a charging capacitor, wherein a horizontal axis indicates a time and a vertical axis indicates the amount of energy. A charging process is progressed until the time Tt from 0 second, and a discharging process is initiated by the trigger operation signal. Although a desirable discharging process is performed along a smooth curve marked as “{circle around (n)}”, if there is no switch in the noise filter unit  20  in the circuit diagram of  FIG. 4 , the charging process is progressed by the inputted supply voltage, so that the amount of energy like the curve “{circle around (a)}” in  FIG. 7  is supplied to the user. 
         [0058]    To solve the charging problem during such a discharging period, the present invention shows two methods. One of the methods is to block the supply voltage inputted during the discharging process by using the controller  50  and the noise filter unit  20  having the switch SW illustrated in  FIG. 4 , and the other is to start discharging at a corresponding time matched with a certain period of the inputted supply voltage illustrated in  FIG. 5 . 
         [0059]    In the circuit of  FIG. 4 , the controller  50  generates the control signal for turning off the input-blocking switch SW during the discharging time, and the noise filter unit  20  is blocked according to the control signal during the discharging time in order to prevent the inputted supply voltage from being supplied. Also, Xenon lamps are often continuous discharged when lamp driving circuit is out of order and PWM control cannot be controlled. At this time, it is possible not to supply continuous energy to Xenon lamp by changing “off” state on the switch SW. A relay operated by an electromagnet or a solid state relay (SSR) operated by a semiconductor has been used as the input-blocking switch SW. Compared with a circuit diagram of  FIG. 5  to be mentioned later, the circuit diagram illustrated in  FIG. 4  has an advantage that a special delay for matching timing is not generated. Since the input-blocking switch SW is a switch for preventing the charging capacitor  80  from being charged by the inputted supply voltage  10  while the charging capacitor  80  is discharged, it is also possible that said switch is provided at any position that can block the electric flow between the supply voltage  10  and the charging capacitor  80  in addition to the noise filter unit  20 . That is to say, the input-blocking switch SW may be equipped at any place capable of switching the electric flow between the supply voltage and the charging capacitor. For instance, the input-blocking switch SW can be positioned even between the double-voltage unit  110  and the switch unit  120 . Also, as another embodiment, it makes the same result of shutting off the power supplied to noise filter unit  20  if the reference voltage supplied to the switch unit  120  is controlled to be almost zero voltage. 
         [0060]      FIG. 5  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. Since the circuit diagram shown in  FIG. 5  has almost similar configuration to the circuit diagram shown in  FIG. 4 , only the features different from those of the circuit diagram of  FIG. 4  will be described below. The circuit diagram of  FIG. 5  shows a noise filter unit  20  from which a switch is removed, and thus a control signal line inputted to the noise filter unit  20  from the controller  50  in  FIG. 4  is unnecessary. Instead, in the circuit diagram of  FIG. 5 , an input wave timing unit  115 , which receives an output signal of the noise filter unit  20  and generates an input wave timing signal at every time such as up or down time of an input waveform, is added between a controller  50  and the noise filter unit  20 . Like shown in  FIG. 8 , the input wave timing unit  115  perceives the input waveform inputted from the noise filter unit  20 , and outputs an input wave timing signal S to the controller  50  at every certain time, and the input wave timing unit can simply be realized by using a photo coupler. An output of the noise filter unit  20  is connected to a photo diode used as an input end of the photo coupler, the photo diode is turned on to generate light if more than a certain voltage is applied, and a light receiving transistor which constitutes an output end of the photo coupler is turned on by receiving the light generated from the photo diode and generates the input wave timing signal S. 
         [0061]      FIG. 8(   a ) illustrates that the input wave timing signal S is outputted at every time whenever a sine wave is increased if the sine wave is inputted from the noise filter unit  20  to the input wave timing unit  115 , and  FIG. 8(   b ) illustrates an example that the input wave timing unit  115  generates a square wave from the input wave inputted from the noise filter unit  20 , and that the input wave timing signal S is generated at every time whenever the square wave is increased and is applied to the controller  50 . 
         [0062]    If the input wave timing signal S is inputted from the input wave timing unit  115 , the controller  50  which constitutes the circuit of  FIG. 5  generates a trigger signal for starting discharging at a proper time and transmits the generated trigger signal to the trigger unit  70 . 
         [0063]    The driving circuit of the IPL apparatus in accordance with the one embodiment of the present invention shown in  FIG. 4  and  FIG. 5  has an advantage of using one of PAM and PWM driving modes if controller  50  controls the width of trigger signal or changes reference voltage setup without changing a circuit configuration, that is, through the same circuit configuration. 
         [0064]      FIG. 6  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. Since the circuit diagram shown in  FIG. 6  has almost similar configuration to the circuit diagram shown in  FIG. 5 , only the features different from those of the circuit diagram of  FIG. 5  will be described below. The controller  50  in the circuit diagram shown in  FIG. 4  and  FIG. 5  calculates proper charging time and/or discharging time, and in the circuit diagram of  FIG. 4 , the trigger signal is generated by blocking the input signal of the noise filter unit  20 , or in the circuit diagram of  FIG. 5 , the trigger signal is generated at a corresponding time matched with the input wave timing signal S outputted from the input wave timing unit  115 . The circuit diagram of  FIG. 6  is characterized in that a voltage divider  195  and an analog to digital converter  97  are additionally provided between a charging capacitor  80  and a controller  50  in order to exactly sense a voltage of the charging capacitor  80 . The voltage divider  195  is a circuit element for measuring a charging voltage of the capacitor  80  while minimizing power consumption, and in the present invention, a voltage Vc of the capacitor  80  is divided within the range of approximately 1/10 to 1/300, and the divided voltage is inputted to the controller  50  through the analog to digital converter  97 . The controller  50  in the circuit diagram of  FIG. 6  senses a voltage level inputted from the analog to digital converter  97 , and generates a trigger signal at a corresponding time matched with an input wave timing signal S outputted from an input wave timing unit  115 . It is needless to say that the voltage divider  195  and the analog to digital converter  97  may be equipped in the circuit diagram of  FIG. 4 , and in this case, the controller  50  generates the trigger signal by blocking the input signal of the noise filter unit  20  if the charging capacitor  80  reaches a desired voltage level. 
         [0065]      FIG. 9  is one embodiment of a driving circuit diagram of an IPL apparatus in accordance with the present invention. In the circuit diagram of  FIG. 9 , for the explanatory convenience, only the main circuit configurations such as a noise filter unit  20 , a rectification unit  91 , a smoothing unit  93 , a double-voltage unit, a constant current supply unit  38 , a reference voltage generator, a switch unit, a charging capacitor, a controller  50 , and a Xenon lamp flash unit  40  are illustrated, and the rest of circuit elements were omitted. In the circuit diagram of  FIG. 9 , a supply voltage  10  corresponds to the supply voltage  10  of  FIG. 4 , a noise filter unit  20 , a rectification unit  91 , and a smoothing unit  93  respectively correspond to the noise filter unit  20 , the rectification unit  91 , and the smoothing unit  93  of  FIG. 4 , a capacitor C 1  and a diode D 1  correspond to the double-voltage unit  110  of  FIG. 4 , a Zener diode D 3 , a Zener temperature compensation circuit unit  125 , and a voltage divider  195  correspond to the reference voltage generator  90  of  FIG. 4 , an SCR  1  corresponds to the switch unit  120  of  FIG. 4 , and a capacitor C 3  corresponds to the charging capacitor  80  of  FIG. 4 . 
         [0066]    First, a double-voltage circuit for boosting a voltage triple times will be described as follows.  FIG. 10  separately illustrates only the double-voltage circuit which only comprises the supply voltage  10 , the noise filter  20 , rectification unit  91 , smoothing unit  93 , the capacitors C 1  and C 3 , the diode D 1 , and the SCR  1  in the circuit of  FIG. 9 . 
         [0067]    First, when the supply voltage  10  supplies “+” voltage, current path “□” flowing through the noise filter  20 , rectification unit  91 , and smoothing unit  93  is formed. And capacitor consisting of rectification unit  91  is charged Vc voltage with the polarity as shown  FIG. 10 . 
         [0068]    Then, when the supply voltage changes “−” voltage, current path “□” flowing through the noise filter  20 , capacitor C 1 , diode D 1  and smoothing unit  93  is formed. Charges (or energies) accumulated at Smoothing unit  93  are accumulated to capacitor C 1  through the diode D 1  and the charges supplied from the supply voltage  10  are also accumulated to the capacitor C 1  simultaneously. Therefore the capacitor C 1  is charged to 2 Vc voltage (almost double voltage of the supply voltage  10 ) with the polarity as shown  FIG. 10 . 
         [0069]    When the supply voltage is changed “−” to “+” in the “on” state of thyristor SCR 1 , new current path “□” flowing through noise filter  20 , capacitor C 1 , thyristor SCR 1  and charging capacitor C 3  is formed beside current path “{circle around (1)}”. At this time, the accumulated charges (or energies) at capacitor C 1  are moved to charging capacitor C 3  through the thyrister SCR 1  and energy supplied by the supply voltage  10  also accumulated to charging capacitor C 3 . Therefore, 3 Vc voltages (almost triple voltage of the supply voltage  10 ) are accumulated to charging capacitor C 3  as shown in  FIG. 10 . As shown in  FIG. 10 , we can see that rectification unit  91  and smoothing unit  93  according to the present invention also contribute to form double voltage. 
         [0070]    Again, in  FIG. 9 , the Zener diode D 3  and the voltage divider  195  form a reference voltage generator. The Zener diode is a circuit element for maintaining a certain voltage all the time, and the certain voltage applied to the Zener diode D 3  generates a reference voltage in accordance with an energy level inputted to a gate terminal of the SCR  1  through a user interface by the voltage divider  195  which is formed with a plurality of switch elements and a plurality of resistors. However, said Zener diode may cause a voltage change if an applied current value is not regular. Such a problem will be described in reference to  FIG. 11 .  FIG. 11  is a graph for illustrating a characteristic of voltage to current operation of a Zener diode. Like shown in  FIG. 11 , it could be understood that if a current which flows in the Zener diode is changed into I2 from I1, a voltage value applied thereto is also changed into V2 from V1. To solve such a problem, the constant current supply unit  38  is employed in  FIG. 9 , and said constant current supply unit  38  may simply be configured as a resistance and constant current diode. 
         [0071]    Another problem of the Zener diode D 3  is a draft that a voltage gets higher when the peripheral temperature rises. Said voltage draft problem in accordance with the temperature rise may be solved by using a Zener temperature compensation circuit unit  125  in the circuit diagram of  FIG. 9 , which is positioned between the voltage divider  195  and a ground and is characterized by lowering a resistance value according to the rise of the peripheral temperature. A thermistor may be used as the Zener temperature compensation circuit unit  125 , and the thermistor performs a function of compensating the voltage increase which occurs in the Zener diode D 3  owing to the temperature rise, whereby the Zener diode D 3  operates as a stable reference voltage source irrespective of the peripheral temperature change. 
         [0072]    Even though the circuit diagram of  FIG. 9  shows that the reference voltage generator is configured with the Zener diode D 3 , the Zener temperature compensation circuit unit  125 , and the voltage divider  195 , it is also possible to form only the voltage divider if the precision of a reference voltage may be sacrificed slightly. In addition, as another configuration, it is also possible to comprise a digital to analog converter between the controller and the gate terminal of the SCR, and to convert a voltage level value inputted from the controller by using the digital to analog converter and to apply the converted value to the gate terminal of the SCR. 
         [0073]    Next, the operation of the SCR (SCR  1 , thyristor) will be described as follows. Although the thyristor (SCR  1 ) is used as a switch in the circuit diagram of  FIG. 9 , said thyristor could be replaced with a triac element. An anode of the thyristor (SCR  1 ) is connected to one terminal of the capacitor C 1  which forms the double-voltage unit, and a voltage of the anode is marked “V1”. A cathode of the thyristor (SCR  1 ) is connected to one terminal of the charging capacitor C 3 , and a voltage of the cathode is marked “V3”, and a voltage of the gate terminal which is the remaining terminal of the thyristor (SCR  1 ) is marked “V2”. A reference voltage which can be set to the gate voltage “V2” of the thyristor (SCR  1 ) is determined by a value between maximum and minimum values of the voltage “V1” applied to the anode terminal. The thyristor SCR  1  shown in  FIG. 9  is turned on when “V1” has a larger value than “V3” and “V2” has a larger voltage than “V3” as much as the threshold voltage. 
         [0074]    After the thyristor SCR  1  is turned on, “V1” gets lower than “V3” then, thyristor SCR  1  is turned off. And even if “V1” gets higher than “V3” while “V2” has a lower value than “V3”, the thyristor SCR  1  cannot be turned on. Therefore charging process is stopped. At this time, the value “V3” is same value of gate threshold minus from the value “V2”. Therefore the value “V3” becomes similar value “V2”. 
         [0075]    Normally, a rectification unit  91  and a smoothing unit  93  in the circuit configuration shown in  FIG. 9  and  FIG. 10  are contributed to form double voltage and the voltage charged to charging capacitor C 3  becomes almost triple the voltage of the supply voltage  10 . Therefore the circuit configuration shown in  FIG. 9  and  FIG. 10  is usually used at the area with 100V ˜120V of the supply voltage  10 . 
         [0076]    On the other hand, almost double energy supplied by supply voltage  10  can be charged to charging capacitor C 3  in the area with 220V of the supply voltage  10 . The circuit configuration excepting a rectification unit  91  and a smoothing unit  93  is proposed in  FIG. 12  and  FIG. 13 . This circuit configuration is suitable to the area with 220V of the supply voltage  10 .  FIG. 12  corresponds to  FIG. 9  and  FIG. 13  corresponds to  FIG. 10 . 
         [0077]    When the supply voltage  10  supplies “−” voltage, current path as shown number “{circle around (1)}” flowing through the noise filter  20 , capacitor C 1 , and diode D 1  is formed. Therefore capacitor C 1  is charged Vc voltage (almost the voltage supplied from supply voltage  10 ) with the polarity as shown  FIG. 13 . 
         [0078]    If the supply voltage is changed “+” to “−” in the “on” state of thyristor SCR 1 , current path “{circle around (2)}” flowing through noise filter  20 , capacitor C 1 , thyristor SCR 1  and charging capacitor C 3  is formed. At this time, the accumulated charges (or energies) at capacitor C 1  are moved to charging capacitor C 3  through the thyrister SCR 1  and energy supplied by the supply voltage  10  is also accumulated to charging capacitor C 3 . Therefore, 2 Vc voltages (almost double voltage of the supply voltage  10 ) are accumulated to charging capacitor C 3  as shown in  FIG. 13 . 
         [0079]    Hereinafter, the operation of the circuit shown in  FIG. 13  will be described below. 
         [0080]    First, suppose that 60 Hz of 220V power is used as a supply voltage, a reference voltage of 340V is applied to a gate of the thyristor (SCR  1 ) by the combination of the voltage divider in accordance with an energy level which is set by the user through the user interface, no electric charges are accumulated in the charging capacitor in an early state, and that the threshold voltage of the thyristor (SCR  1 ) is OV. Under said condition, a maximum peak value of the corresponding supply voltage is 310V approximately. Since electric charges supplied by the supply voltage  10  is doubled with the electric charges accumulated in the capacitor C 1 , a bias voltage of the “V1” terminal is 310V and the amplitude is 310V. Further, a voltage varying between OV and 620V is applied to the “V1” terminal because a sine-wave voltage having a maximum peak value of 620V is applied. 
         [0081]    If the supply voltage is applied under said condition, the anode voltage of the thyristor (SCR  1 ) gets higher than the cathode voltage (V1&gt;V3) and the gate voltage V2 gets higher than the threshold voltage for turning on the thyristor compared with the cathode voltage V3. Thus, the thyristor is conducted to charge the charging capacitor. If the waveform applied to the V1 terminal gets lower than the cathode voltage (charging voltage of the charging capacitor) while going down by passing through the peak, the thyristor (SCR  1 ) stops operating. Then, as the input waveform starts increasing in the next cycle, the anode voltage V1 of the thyristor (SCR  1 ) gets higher than the voltage V3 of the cathode terminal of the thyristor (SCR  1 ), and under the condition “V2&gt;V3”, the thyristor (SCR  1 ) is conducted again to progress the charging process. 
         [0082]    The charging process is progressed as said operation is repeated until the voltage charged in the charging capacitor C 3  reaches a voltage which is subtracted as much as the threshold voltage for turning on the thyristor (SCR  1 ) from the reference voltage applied to the gate of the thyristor (SCR  1 ). Then, power is supplied to the Xenon lamp flash unit  40  by a trigger operation signal which is not shown in  FIG. 12 . 
         [0083]    While specific embodiments of the invention have been described and shown above, it is obvious that the invention can be modified in various forms by those skilled in the art without departing from the technical spirit of the invention. The modified embodiments should not be understood separately from the spirit and scope of the invention and should be considered as belonging to the appended claims of the invention. Although the audio communication has been mainly described above, the invention can be easily applied to a video communication. In this case, the phone  500  means a television phone and a protocol suitable for a video should be used instead of the SIP protocol.