Abstract: In a pixel circuit of a display device in which display luminance is controlled by a holding voltage of the capacitor Cst, a gate terminal of a drive transistor M1 is connected to a source terminal of the drive transistor M1 via a capacitance selection transistor M3 and the holding capacitor Cst and is also connected to the source terminal via only an auxiliary writing capacitor Cwa. During a data writing period Tw, the capacitance selection transistor M3 is turned off, and data voltage is provided from a data signal line Dj to the auxiliary writing capacitor Cwa via a writing control transistor M2. Thereafter, the writing control transistor M2 is turned off, the capacitance selection transistor M3 is turned on, so that charges are redistributed between the auxiliary writing capacitor Cwa and the holding capacitor Cst, whereby a driving holding voltage is determined.

Abstract: A bi-directional switch for an inductive machine is described. The bi-directional switch may include a first power semiconductor transistor with a first source, a first drain, and a first gate. The bi-directional switch may further include a second power semiconductor transistor with a second source, a second drain, and a second gate. The bi-directional switch may include the second source connected to the first source. The bi-directional switch may include a soft-starter device including a control circuit configurable to provide a first control signal to the first power semiconductor transistor and a second control signal to the second power semiconductor transistor.

Abstract: A stage including: an output circuit connected to a first node and a second node; an input connected to a third node and a fourth node; and a plurality of signal processors between the output and the input, the plurality of signal processors electrically connecting the first node and the third node and electrically connecting the second node and the fourth node, wherein the input includes: a seventh transistor connected between a first input terminal and the fourth node and having a gate electrode connected to a second input terminal; a plurality of eighth transistors serially connected between the third node and the second input terminal and having gate electrodes connected to the fourth node; and a ninth transistor connected between the third node and a second power source and having a gate electrode connected to the second input terminal.

Abstract: A pixel includes a display element, a driving transistor which controls an amount of a driving current flowing toward the display element, a first capacitor connected to a gate of the driving transistor, a scan transistor which transfers a data voltage to a source of the driving transistor, first and second compensation transistors connected to each other in series between the gate and a drain of the driving transistor, first and second emission control transistors which generates a path of the driving current between the display element and a power line, and a second capacitor connected between a floating node between the first and second compensation transistors and a gate of the second emission control transistor.

Abstract: A driver is configured to maintain a threshold compensation transistor to be ON to write a threshold compensation voltage to a storage capacitor in a threshold compensation period, and write a data signal to the storage capacitor in a data write period after the threshold compensation period. A pulse width of control signal is twice or more as long as the data write period. The driver circuit is configured to turn ON a first transistor with a start edge of a first control signal pulse before the data write period starts, maintain the first transistor to be ON and turn ON a second transistor with a start edge of a second control signal pulse to start the data write period, and turn OFF the first transistor with an end edge of the first control signal pulse to end the data write period.

Abstract: A light-emitting device includes a plurality of area drive circuits. The area drive circuits each include a first write control transistor and a second write control transistor. Each of the area drive circuits has a first write period in which the first and the second write control transistor are maintained in an on state, a first write stop period in which the first and the second write control transistor are maintained in an off state, and a second write period in which the first write control transistor is maintained in the off state and the second write control transistor is maintained in the on state, the periods being provided in this order in one frame period from when the first write control transistor changes from the off state to the on state to when the first write control transistor next changes from the off state to the on state.

Abstract: An OLED display and an operation method thereof, which are capable of preventing malfunctions caused by the influence of external noise on an extended cable when a display panel is separated from a set part by a predetermined distance or longer, are discussed. The OLED display includes a timing controller embedded in the set part separated from the display module by a predetermined distance and configured to control a reset signal for cancelling a safety mode to be transmitted to the display module in order to prevent the safety mode from being abnormally maintained due to the influence of external noise on a cable used to connect the display module and the set part when the safety mode for displaying a black screen is executed, to thereby prevent the display from continuously executing the safety mode to consistently display the black screen.

Abstract: In a discharge lamp driver, a control section is configured to alternately repeat a first period in which an AC current is supplied and a second period in which a DC current is supplied, and when a first drive power lower than a rated power of the discharge lamp is supplied and an accumulated lighting time of the discharge lamp is shorter than a predetermined time, the control section is configured to set the length of the first period to be greater than that in a case where the first drive power is supplied and the accumulated lighting time is equal to or longer than the predetermined time, and set the frequency of the AC current during the first period to be higher than that in the case where the first drive power is supplied and the accumulated lighting time is equal to or longer than the predetermined time.

Abstract: A sensor, such as a motion sensor and/or an occupancy sensor, a soft switch relay controller, or a power pack can significantly reduce the in-rush current and thereby extend the life of relays and other electrical components susceptible to damage caused by in-rush current or voltage surges. The sensor, soft switch relay controller, and/or power pack can reduce the in-rush current when enabling or disabling a light source.

Abstract: Multiple relays are connected in parallel by including one or more semiconductor devices connected across the relay contacts. The semiconductor devices are triggered to conduct and shunt transient currents during the opening and closing of the relay contacts to protect the relay contacts from overcurrent and to eliminate arcing during relay switching. This permits a combination of smaller relays to replace a larger and more expensive relay in applications that require switching of large load currents.

Abstract: The present disclosure provides a magnetic resonance type wireless charging circuit, and belongs to the field of wireless charging technology. The magnetic resonance type wireless charging circuit comprises: a high frequency oscillation circuit configured to generate an initial oscillation signal; and a driving circuit configured to generate a transmission signal using the initial oscillation signal; wherein the driving circuit comprises one stage of driving sub-circuit or n stages of driving sub-circuits with (n?1) stages of Direct Current (DC) blocking circuits serially connected thereamong in an alternate manner, where n?2 and n is an integer, and each stage of driving sub-circuit comprises a frequency doubling circuit and a first frequency selection circuit which are connected in series.

Abstract: Some embodiments relate to dimmer control circuitry for LED lighting, comprising: phase control circuitry to control the supply of voltage to at least one LED load, wherein the phase control circuitry comprises an AC switch to selectively provide voltage to the LED load for a first portion of a half cycle of an AC supply voltage, and a drive component to drive the AC switch so that the AC switch remains on for the first portion of the half cycle; and load switching circuitry to couple a dissipative load to an output of the AC switch during a second portion of the half cycle, wherein the second portion overlaps with the first portion.

Abstract: A high intensity discharge lamp (HID) control circuit and method are provided in the present invention. The circuit includes a first winding and a second winding, both of which are coupled with a series-connected inductor of an HID lamp circuit; a current zero point detector for detecting an inductor current zero crossing signal in the HID lamp circuit; an inductor current signal generator for generating an inductor current signal in the circuit to indicate a current value of the HID lamp; a modulator having input terminals connected to the current zero point detector and the inductor current signal generator, respectively, and an output terminal connected to a driving circuit for the HID lamp; and the driving circuit for driving switches in the HID lamp control circuit.

Abstract: The lighting circuit comprises an AC input connectable to receive an AC input voltage, a switched LED array comprising a plurality of LEDs reconfigurable into a plurality of configurations and having an input for receiving a LED driving voltage, a switched capacitor array having an input for receiving a charging voltage and an output selectively connectable to the input of the switched LED array and comprising a plurality of capacitors and switches connected to selectively couple the capacitors across the input or output, a first switched rectifier connected between the AC input and the switched LED array, a second switched rectifier connected between the AC input and the switched capacitor array, and, a control system configured to monitor the AC input voltage and control the switched LED array, the switched capacitor array and the first and second switched rectifiers based on the AC input voltage and a desired light output.

Abstract: A light-emitting device in which variation in luminance among pixels is suppressed. The light-emitting device includes a pixel; a first circuit configured to generate a signal containing information on a value of current extracted from the pixel; and a second circuit configured to correct an image signal in accordance with the signal. The pixel includes a light-emitting element; a transistor for controlling supply of the current to the light-emitting element in accordance with the image signal; a first switch configured to control connection between a gate and a drain of the transistor or between the gate of the transistor and a wiring; and a second switch configured to control extraction of the current from the pixel.

Abstract: The present disclosure discloses a pixel unit driving circuit and method, and a pixel unit of an Active Matrix Organic Light Emitting Diode AMOLED panel and a display apparatus.

Abstract: A luminary dimming system having a three terminal dimming unit. The dimming unit includes a power controller and a receiver and is responsive to dimming directives received by the receiver. The power controller controls a buck switch and a freewheel switch in a manner that allows reduction of alternating current voltages. Such voltage reduction is accomplished in a manner that preserves the waveform of the source voltage and the power factor exhibited by the luminary.

Abstract: LED controllers, LED lighting systems and control methods capable of providing an average luminance intensity independent from the variation of an AC voltage. A string of LEDs are divided into LED groups electrically connected in series between a power source and a ground. A LED controller has path switches, each for coupling a corresponding LED group to the ground. A management center controls the path switches, for making an input current from the power source to the string substantially approach a target value. A line waveform sensor coupled to the power source holds a representative signal during a cycle time of the power source. The representative signal is in response to an attribute of the power source, and substantially determines the target value.

Abstract: Provided is a step up/down converter, in which the inductor current can be easily detected by a simple configuration in any connecting mode of the switches.

Abstract: A backlight module and a liquid crystal display (LCD) device thereof are proposed. The backlight module includes a DC/DC converter producing a positive/negative voltage level. The backlight module can output the positive and negative levels of driving voltage from an output end of the inverter to drive LEDs through alternately switching. Besides, a constant current can be obtained with designs of power on/off periods and energy-storing inductors to prevent LEDs employing current limiting resistors from having too low current efficiency and from being burnt out.

Abstract: An image display device including a light-emitting element configured to emit light corresponding to a current flowing therethrough; a driving element that is connected to the light-emitting element and configured to control light emission of the light-emitting element; and a control unit configured to apply a reverse bias voltage to a first n-type driving element whose the threshold voltage determined at a specific time is equal to or higher than a positive predetermined voltage level for shifting the threshold voltage of the first n-type driving element in a negative direction, and not apply the reverse bias voltage to a second n-type driving element whose the threshold voltage determined at the specific time is lower than the positive predetermined voltage level for shifting the threshold voltage of the second n-type driving element in a positive direction when the light-emitting element does not emit light.

Abstract: There is provided an LED drive circuit that can be connected to an alternating-current power supply through a phase control dimmer and that drives an LED load, the LED drive circuit including: an LED current control circuit; a capacitance component and a resistance component that are connected in series between an input of the LED current control circuit and a reference potential; a switch element that is connected to both ends of the resistance component; and a switch control portion that turns off the switch element for a given period of time after a timing when the phase control dimmer is turned on and that turns on the switch element after the given period of time elapses.

Abstract: A method and apparatus for controlling a light string is provided. A controller is coupled to the light string and is used to bias one or more of the multicolor LEDs within each bulb on the light string. Using a prearranged determination of 1) the multicolor LEDs within each bulb, 2) the placement of the bulbs within the light string, and 3) the proper biasing of the plurality of leads within the light string, the controller can be used to change the entire light string from one complex holiday color scheme to another using a simple switching mechanism to select from one a of a plurality of desired color schemes.

Abstract: A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

Abstract: A DC/DC converter 10 has a high-side transistor QH as a switching element and a low-side transistor QL as a synchronous rectifier element. A first primary electrode D and secondary primary electrode S of the high-side transistor QH are connected to an input voltage VIN and an external terminal T1, respectively. A detection transistor QD is provided in a row with the high-side transistor QH, and the ON voltage of the high-side transistor QH when ON is output as detection voltage VQD from the detection transistor QD. The output detection voltage VQD is added to a feedback voltage VFB1 by an adder CB, and inputted to a comparator CMP1. The ON period of a one-shot pulse PS1 outputted from the comparator CMP1 is regulated so as to be in direct proportion to the sum of the detection voltage VQD and the feedback voltage VFB1.

Abstract: In one embodiment, a charge-pump controller is formed to control a value of current supplied to a load.

Abstract: An LED drive circuit (10) for driving an LED circuit (220) includes: a constant current driver (110) including transistors (111-114) whose collector terminals are respectively connected with LED rows (221-224) connected with each other in parallel and whose emitter terminals are grounded; and an LED drive control section (120) for setting a voltage to be commonly applied on the LED rows (221-224), the setting being performed in accordance with a maximum base current out of base currents of the transistors (111-114).

Abstract: A lighting device for lighting a solid-state light source includes: a DC power circuit unit for converting a power of an input DC power source using a switching element and flowing a current through a solid-state light source; and a control unit for performing a first switching control in which the switching element is turned on/off at a first high frequency and a second switching control in which an ON/OFF operation of the switching element is intermittently stopped at a second frequency lower than the first frequency of the first switching control. When the current flowing through the solid-state light source is changed, the second frequency is varied.

Abstract: Disclosed is an improved light-emitting device for an AC power operation. A conventional light emitting device employs an AC light-emitting diode having arrays of light emitting cells connected in reverse parallel. The arrays in the prior art alternately repeat on/off in response to a phase change of an AC power source, resulting in short light emission time during a ½ cycle and the occurrence of a flicker effect. An AC light-emitting device according to the present invention employs a variety of means by which light emission time is prolonged during a ½ cycle in response to a phase change of an AC power source and a flicker effect can be reduced. For example, the means may be switching blocks respectively connected to nodes between the light emitting cells, switching blocks connected to a plurality of arrays, or a delay phosphor.

Abstract: A damper circuit is operable to dampen resonance of an electromagnetic interference filter when a phase dimmer activates. The damper circuit includes a capacitor and a bipolar junction transistor (BJT). The capacitor includes a first terminal and a second terminal. The BJT includes a control terminal, a collector terminal, and an emitter terminal. The control terminal of the BJT receives a control signal to make the BJT operate in the amplified area, and the collector terminal of the BJT is electrically connected to the second terminal of the capacitor. The first terminal of the capacitor receives the resonance generated to by the electromagnetic interference filter, and the BJT and the capacitor cooperate to dampen the resonance generated by the electromagnetic interference filter when the BJT operates in the amplified area.

Abstract: A lighting power source provides AC or DC power as needed to power an electric light source. A first switching element and a diode are coupled in series across output ends of a DC power source, with a second switching element coupled across the diode. An inductor forms an output loop with the diode. A driving capacitor has a first end coupled to a node between the first switching element and the diode. A charging power source is coupled to a second end of the driving capacitor and supplied with power from the DC power source. During a charging operation, a control circuit charges the driving capacitor by turning on the second switching element while maintaining the first switching element in an OFF state. During a normal operation which follows the charging operation the control circuit repeatedly turns on/off the first switching element while maintaining the second switching element in the OFF state.

Abstract: According to one embodiment, a power supply device includes a switching circuit and a control circuit. The switching circuit adjusts, according to ON-OFF control for an input voltage, electric power supplied to a lighting load. The control circuit controls ON and OFF of the switching circuit such that the electric power supplied to the lighting load coincides with target power. The control circuit that operates at a frequency equal to or higher than a switching frequency of the switching circuit is used. That is, a control frequency of the control circuit for the switching circuit is equal to or higher than the switching frequency of the switching circuit.

Abstract: A driving device includes a switching power supply circuit to convert input power to output power; a first switching element which opens and closes a circuit of a load; an output capacitor connected in parallel to the load and the first switching element; a selection switch disposed between the inductor and the output capacitor, the selection switch switching between a first selection state where the load is electrically connected to the inductor and the second selection state where a reference potential portion is electrically connected to the inductor; a timing controller which operates the switching power supply circuit while the first switching element is closed; and a controller which puts the selection switch into the second selection state before the first switching element is closed.

Abstract: An organic light emitting display comprises: a driving TFT comprising a gate connected to a node B, a drain connected to an input terminal of high-potential cell driving voltage, and a source connected to the organic light emitting diode through a node C; a first switching TFT for switching the current path between a node A and the node B in response to a light emission control signal; a second switching TFT for initializing the node C in response to an initialization signal; a third switching TFT for initializing either the node A or the node B in response to the initialization signal; a fourth switching TFT for switching the current path between a data line and the node B in response to a scan signal; a compensation capacitor connected between the node B and the node C.

Abstract: A power supply includes: a step-down chopper unit for stepping down a DC voltage from a DC power source to a voltage required for lighting; and a dimming control unit which dims the light source by alternately repeating a switching ON period during which a drive signal having a frequency higher than that of the dimming signal is supplied to the switching element and a switching OFF period during which the supply of the drive signal to the switching element is stopped. Further, the power supply includes an inrush current prevention unit for preventing an inrush current occurring when the DC power source is turned on, and a compensation unit which applies a drive voltage to the thyristor in the switching OFF period.

Abstract: A circuit arrangement for operating a high-pressure discharge lamp with an operating circuit for the high-pressure discharge lamp with an input for receiving a switch-on/switch-off signal for the high-pressure discharge lamp and at least one output for providing an operating signal to the high-pressure discharge lamp, wherein the operating circuit is designed to reduce the power of the operating signal provided at the at least one output once a switch-off signal has been received at its input, wherein the operating circuit furthermore designed to provide the operating signal as an AC signal above a predeterminable power threshold value and as a quasi DC signal below the predeterminable power threshold value.

Abstract: A two-wire AC switch suppressing heat from a bidirectional switch element inside the switch is provided. The two-wire AC switch 100a connected between an AC power supply 101 and a load 102 includes: a bidirectional switch element 103 which flows passing current bi-directionally, selects whether to flow or block the current, is connected in series with the AC power supply 101 and the load 102 to form a closed-loop circuit, and is made of a group-III nitride semiconductor; a full-wave rectifier 104 performing full-wave rectification on power supplied from the AC power supply 101; a power supply circuit 105 smoothing a voltage after the full-wave rectification to generate DC power; a first gate drive circuit 107 and a second gate drive circuit 108 each outputting a control signal to the bidirectional switch element 103; and a control circuit 106 controlling the first and second gate drive circuits 107 and 108.

Abstract: An asymmetric end-of-life protection circuit with single-point voltage measurement is provided for an electronic ballast having two lamp connection terminals. A grounding circuit includes a capacitor and a first resistor coupled in parallel between a first lamp connection terminal and ground, and is effective to drain the second lamp connection terminal to ground. A lamp voltage detection circuit is coupled between the first lamp connection terminal and ground and measures the lamp voltage from the first lamp connection terminal. A controller is effective to shut down the ballast based on an output signal from the lamp voltage detection circuit being greater than a first predetermined threshold value or less than a second predetermined threshold value.

Abstract: A discharge lamp lighting device capable of preventing magnetic saturation of an inductor connected with an output of an inverter. An inverter 12 comprises a first set of switching elements 32, 33 for switching an output voltage of the inverter 12 to a positive polarity and a second set of switching elements 31, 34 for switching the output voltage thereof to a negative polarity. At the start-up of a lamp 20, each of the switching elements 31 to 34 is allowed to perform switching operations in such a pattern that after turning on and off the first set of the switching elements 32, 33 more than once, the second set of switching elements 31, 34 are allowed to turn or and off more than once. Accordingly, energy stored in the inductor 37 is discharged during a temporary off-period, thus permitting the inductor 37 to be prevented from being magnetically saturated.

Abstract: In a driving circuit for controlling a brightness of a light emitting diode based on a duty ratio of a pulse-width modulation signal, an integration circuit is disposed on a connecting line between a gate of a first transistor coupled with a constant current source and a gate of a second transistor coupled in series with a light emitting diode. The integration circuit smoothes a change in a gate voltage of the first transistor and transmit a smoothed change in the gate voltage to the gate of the second transistor. A third transistor is coupled between a ground and a portion of the connecting line located between the gate of the first transistor and the integration circuit. The third transistor is activated and deactivated based on the duty ratio, thereby changing the gate voltages of the first transistor and the second transistor.

Abstract: A discharge lamp ballast is provided with a feedback control operation to provide optimal lamp current flow during an electrode heating operation. A startup circuit coupled together with a discharge lamp between output terminals of a DC-AC power converter having a plurality of switches. The startup circuit generates a high voltage to ignite the lamp. A lamp current sensor detects an amplitude of an output current to the lamp. A control circuit controls the switches in accordance with each of a plurality of control operations including a startup operation to ignite the lamp using the high voltage generated by the startup circuit, an electrode heating operation wherein an operating frequency of the switches is controlled to set the amplitude of the detected output current to a predetermined target current amplitude, and a normal operation wherein the operating frequency is reduced to maintain stable lighting of the lamp.

Abstract: Drivers and ballast circuits are presented having a boost converter with a triac compatibility circuit providing regulated current load to accommodate phase-cutting triac circuit holding current requirements, including auto switching driver circuit with overvoltage protection and an auto leveling circuit to regulate against thermal and load fluctuations.

Abstract: A driver circuit is configured to drive light-emitting elements. The driver circuit includes a light-emitting element, a power switching element, a control circuit, and a charge pump circuit. The power switching element includes a first terminal connected to the light-emitting element and turns on and off the light-emitting element. The control circuit is connected to a second terminal of the power switching element and controls a switching operation of the power switching element. The charge pump circuit is connected between the control circuit and a power source for the light-emitting element and supplies current to the control circuit for driving the control circuit.

Abstract: A load driving apparatus is disclosed. The load driving apparatus includes a driving signal generator and a controller. The driving signal generator is used for providing a driving signal to a load. The controller is used for generating and providing a control signal to the driving signal generator. The driving signal generator generates N integer signals and M fractional signals in a driving period to form the driving signal according to the control signal. N and M are positive integers, and an amplitude of the integer signals is greater than an amplitude of each of the fractional signals.

Abstract: A voltage-driven pixel circuit, a driving method thereof and a display panel including the voltage-driven pixel circuit are disclosed. The voltage-driven pixel circuit comprises a driving transistor, a retaining transistor, a switching transistor, a compensating transistor, a storage capacitance and an OLED device. The technical solutions disclosed here compensate for the unevenness of the threshold voltage of the N-type TFT transistors and OLED efficiently.

Abstract: The present disclosure discloses an AMOLED pixel unit driving circuit and method, an AMOLED pixel unit and a display apparatus, the AMOLED pixel unit driving circuit includes: a switching unit with a first input terminal connected to a current source for supplying a charging current and a second input terminal connected to an OLED; a storage capacitor with a first terminal connected to an output terminal of the switching unit and a second terminal connected to a low level; a driving TFT with a gate electrode connected to the first terminal of the storage capacitor and a source electrode connected to the low level; and a current dividing unit with a first terminal connected to the low level. The embodiments of the present disclosure enable a relatively large scale to exist between the charging current Idata and the current loled flowing through the OLED.

Abstract: The present disclosure discloses a pixel unit driving circuit and method, and a pixel unit of an Active Matrix Organic Light Emitting Diode AMOLED panel and a display apparatus.

Abstract: An electronic ballast for operating at least two discharge lamps is provided, which may include a starting detection apparatus for detecting whether one of the discharge lamps has been started; wherein a drive circuit includes an input, which is coupled to a starting detection apparatus, wherein a threshold value entry apparatus is designed to enter a second threshold value for a setpoint value of a total current through at least two inductances, wherein the second threshold value has a smaller magnitude than a first threshold value; and wherein the drive circuit is designed to drive a first electronic switch and a second electronic switch taking into consideration the first threshold value as setpoint value prior to detection of the starting of a discharge lamp by the starting detection apparatus, and taking into consideration the second threshold value as setpoint value.

Abstract: Provided is a discharge lamp lighting device, which can control a load precisely while improving the practicability. When the difference of a count number (Nn) becomes a predetermined threshold value or less, a predictor circuit (35) predicts the timing, at which a current value (iQ1) becomes a peak value, on the basis of the rate of change of the difference. A switch selecting circuit (38), which is driven with a clock frequency higher than the sampling frequency of a first converter unit (32), turns off a field effect transistor (Q1) at the turn-off timing, and turns on a field effect transistor (Q2). A plurality of A/D converters (37a) are subjected to a multi-rate control, thereby to correct the threshold value of the predictor circuit (35) on the basis of the peak value of a lamp current (iOUT).

Abstract: An LCD backlight driving device with an isolating transformer comprises a DC power supply, a square wave generator, a square wave controller, said isolating transformer and a driver transformer; wherein said isolating transformer has a primary side connected to said square wave generator and a secondary side connected to said driver transformer, since said isolating transformer is placed between said square wave generator and said driver transformer, it helps to effectively shorten a safety distance required for setting up said driver transformer; the present invention uses said isolating transformer to shorten the safety distance required than that of using said driver transformer directly and to decrease an area in implementing a circuit board and to cut cost of said device.