JP2013232360A - Driver of field emission lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance versatility and applicability (expansibility) by making applicable to illumination systems in various fields including various field emission lamps, and to make the whole device compact by reducing the number of components while reducing power consumption and cost.SOLUTION: The driver of field emission lamp includes a voltage stabilization circuit 6 receiving a DC voltage Vsg for gate and outputting a plurality of stabilization voltages V1dg ... Vndg for gate, and a plurality of gate voltage control circuits 71 ... 7n receiving the stabilization voltages V1dg ... Vndg for gate, respectively, outputting the gate application voltages V1g ... Vng having at least adjusted magnitudes of voltage, and applying them to the gates of a plurality of field emission lamps L1 ... Ln, respectively.

Description

  The present invention relates to a drive device for a field emission lamp suitable for use in a field emission lamp that excites and emits a phosphor with electrons emitted from an electron emission source.

  A field emission lamp that emits light by exciting a phosphor with electrons emitted from an electron emission source is known, and a dedicated driving device is usually used for light emission of the field emission lamp.

  Conventionally, as this type of driving device, a driving device for a field emission lamp disclosed in Patent Document 1 is known. The driving device disclosed in the document 1 includes a driving circuit that outputs a switching signal, a switching circuit that switches on / off a switching element by the switching signal to switch a DC input voltage, and boosts the switched input voltage. A field emission lamp driving device comprising a step-up transformer that rectifies the output voltage of the step-up transformer and outputs a DC output voltage, and uses the step-up transformer and the floating capacitance of the step-up transformer And a drive circuit having a function of matching the on / off timing of the switching signal with the resonance circuit.

  By the way, field emission lamps have variations in the characteristics of electron emission sources and phosphors, manufacturing variations in the distance between electrodes, and the like. Therefore, even when a plurality of field emission lamps are driven by the same voltage, all field emission lamps are used. It is not easy to make the mold lamp emit light uniformly. Therefore, in order to solve this problem, it is necessary to prepare a plurality of driving devices for driving each field emission lamp. However, the use of a driving device for each field emission lamp causes problems that cannot be ignored, such as an increase in cost, an increase in the size of the entire device, and an increase in power consumption, even if uniformity can be ensured.

  On the other hand, a driving device aimed at solving problems such as an increase in cost and an increase in size when using a plurality of field emission lamps is also known from Patent Document 2, which includes a plurality of electric fields. A field emission lamp driving apparatus that drives an emission lamp with a representative lamp composed of a predetermined number of lamps as a reference, and controls a stabilization voltage for generating a representative gate voltage suitable for the representative lamp. The first control unit for driving and controlling the representative lamp with the representative gate voltage and the other lamps other than the representative lamp are driven with the gate voltage obtained by dividing the stabilizing voltage for giving the representative gate voltage. There is disclosed a field emission lamp driving device including a second control unit that controls the voltage dividing ratio to drive the same power as that of the representative lamp.

JP 2009-238414 A JP 2011-187365 A

  However, the above-described conventional field emission lamp driving device, particularly the driving device for driving a plurality of lamps, has the following problems to be solved.

  First, the conventional driving apparatus for driving a plurality of field emission lamps is based on the premise that the plurality of field emission lamps have the same standard. In other words, the purpose is to correct the variation between the field emission lamps, and no further assumption is made. On the other hand, in an actual usage mode for driving a plurality of field emission lamps, various types of lamps such as headlights, backlights, direction indicator lamps, indoor lights, etc., such as automobile lamps. Is not only a problem of variation. In the end, the conventional driving device does not assume that various lamps with different standards (types) are driven by a single driving device, so that it is difficult to cope with them. It is not enough from the viewpoint of applicability (development).

  Second, when a plurality of field emission lamps with different specifications are caused to emit light by supplying a plurality of different stabilization voltages, an increase in the number of components is inevitable. Therefore, it is an important issue to suppress as much as possible the overall size of the device, the increase in power consumption and the cost increase, and it is positioned as one of the most important issues especially when it is disposed in a limited space such as an automobile. . However, since the conventional drive device does not assume such a problem, it suppresses an increase in the size of the entire device, an increase in power consumption, and an increase in cost, and also corrects variations among the field emission lamps. There was room for further improvement to meet these demands to drive field emission lamps of different standards (types) accurately and stably.

  An object of the present invention is to provide a driving device for a field emission lamp that solves the problems in the background art.

  In order to solve the above-mentioned problems, the present invention switches the DC input voltage Vi by controlling the on / off of the switching elements 3a and 3b by the signal circuit 2 that outputs the switching signals Sa and Sb and the switching signals Sa and Sb. Switching circuit 3 for boosting, boosting transformer 4 for boosting the switched input voltage Vi, and rectifying the output voltage Vto of the boosting transformer 4, and at least supplied to the gates L1g ... Lng of the field emission lamps L1 ... Ln. When a field emission lamp driving device 1 is provided comprising a gate DC voltage Vsg for output and a rectifier circuit 5 for outputting anode DC voltage Vsa for supply to anodes L1a... Lna, the gate DC voltage Vsg is Input and output a plurality of gate stabilization voltages V1dg... Vndg The stabilization circuit 6 and the gate stabilization voltages V1dg... Vndg are input, and at least the gate applied voltages V1g... Vng adjusted in voltage magnitude are output to output the gates L1g of the plurality of field emission lamps L1. A plurality of gate voltage control circuits 71... 7n respectively applied to Lng.

  In this case, according to a preferred aspect of the invention, the rectifier circuit 5 can be a multiple voltage rectifier circuit 5p configured by combining a plurality of diodes Ds... Connected in series and a plurality of capacitors Cs. . On the other hand, the voltage stabilizing circuit 6 is provided with a withstand voltage input circuit 11 in which a plurality of voltage control elements 8s..., 8sc are sequentially connected in series, and output from the rectifier circuit 5 to the voltage input portion of the withstand voltage input circuit 11. The gate stabilization voltage V1dg is output from the voltage control element (first specific voltage control element) 8sc to which the minimum voltage is added among the plurality of voltage control elements 8s. In addition, a stabilization control signal Sc that stabilizes the gate stabilization voltage V1dg can be applied to the control input unit 8scg of the first specific voltage control element 8sc. The voltage stabilizing circuit 6 includes a voltage dividing circuit 12 that divides the gate stabilizing voltage V1dg output from the first specific voltage control element 8sc and a divided voltage Vp obtained from the voltage dividing circuit 12. A voltage feedback circuit 13 that is applied to the control input unit 8scg of the first specific voltage control element 8sc as the control signal Sc can be provided. At this time, the voltage feedback circuit 13 is provided with a feedback transistor 11x in which a collector and an emitter are connected between the voltage output unit 8scs and the control input unit 8scg of the first specific voltage control element 8sc, and the voltage dividing circuit 12 obtains the divided voltage. The voltage Vp can be applied to the base of the feedback transistor 11x via the Zener diode Dtp.

  Further, the voltage stabilization circuit 6 receives the gate stabilization voltage (first gate stabilization voltage) V1dg output from the voltage output unit 8scs of the first specific voltage control element 8sc as the first gate voltage control circuit (first And a voltage dividing output circuit 14 that divides the first gate stabilizing voltage V1dg into a plurality of other gate stabilizing voltages V2dg... Vndg. The gate stabilization voltages V2dg... Vndg obtained from the Nth gate stabilization voltages V2dg, V3dg... Vndg (N is 2, 3... N, and n is an integer), respectively. 7n can be given to each. In this case, the voltage dividing output circuit 14 can be provided with a plurality of voltage control elements 8g connected in series. In addition, the gate voltage control circuit 71 can be provided with a voltage adjustment circuit 15 that controls the gate application voltage V1g... By the control voltage V1c. It is desirable to use FETs (field effect transistors) for the voltage control elements 8 s..., 8 sc, 8 g.

  The field emission lamp driving apparatus 1 according to the present invention having such a configuration has the following remarkable effects.

  (1) In addition to eliminating variations in light emission between a plurality of field emission lamps L1 of the same standard, when a plurality of field emission lamps L1 having different standards (types) are caused to emit light simultaneously, Each of the field emission lamps L1,... Can be made to emit light with an accurate luminance so as to become the original standard. Therefore, it can be applied to illumination systems in various fields including a plurality of various field emission lamps L1,.

  (2) A single case is used for both emitting a plurality of field emission lamps L1 of the same standard, and a plurality of field emission lamps L1 having different standards (types). This can be dealt with more accurately. Therefore, it is possible to effectively reduce the number of parts, further reduce the size of the entire device, reduce power consumption, and reduce costs. In particular, the illumination system for automobiles equipped with lamps of various standards (types). It is optimal to apply to.

  (3) If a multiple voltage rectifier circuit 5p configured by combining a plurality of series-connected diodes Ds... And a plurality of series-connected capacitors Cs. Both the gate DC voltage Vsg and the anode DC voltage Vsa can be easily obtained. In addition, by combining with the step-up transformer 4, the DC voltages Vsg and Vsa having a necessary magnitude can be obtained easily and reliably.

  (4) According to a preferred embodiment, the voltage stabilizing circuit 6 is provided with a withstand voltage input circuit 11 in which a plurality of voltage control elements 8 s... And 8 sc are sequentially connected in series. Stabilization for the gate from the voltage control element (first specific voltage control element) 8sc to which the DC voltage Vsg output from the rectifier circuit 5 is input and the minimum voltage is added among the plurality of voltage control elements 8s. If the voltage V1dg is output and the stabilization control signal Sc for stabilizing the gate stabilization voltage V1dg is applied to the control input portion 8scg of the first specific voltage control element 8sc, the gate DC voltage Vsg However, even if the voltage reaches a high voltage of 10 [kV] or more due to fluctuations, etc., the voltage control elements 8s,. Can therefore, when implementing the withstand voltage and high voltage control input system circuit, by reducing the use and parts of a low withstand voltage components, it is possible to improve the reliability and cost-down.

  (5) According to a preferred embodiment, the voltage stabilizing circuit 6 divides the gate stabilizing voltage V1dg output from the first specific voltage control element 8sc, and the divided voltage obtained from the voltage dividing circuit 12 By providing the voltage feedback circuit 13 for applying Vp to the control input portion 8scg of the first specific voltage control element 8sc as the stabilization control signal Sc, a simple circuit configuration with a small number of components is required for realizing voltage stabilization. Can be easily realized.

  (6) According to a preferred embodiment, the voltage feedback circuit 13 is provided with a feedback transistor 11x having a collector and an emitter connected between the voltage output unit 8scs and the control input unit 8scg of the first specific voltage control element 8sc, and the voltage dividing circuit 12 If the divided voltage Vp obtained from the above is applied to the base of the feedback transistor 11x via the Zener diode Dtp, voltage feedback for realizing voltage stabilization with respect to a target (necessary) high voltage is realized. The circuit 13 can be configured easily and reliably.

  (7) According to a preferred embodiment, the voltage stabilization circuit 6 is provided with the first gate stabilization voltage V1dg output from the voltage output unit 8scs of the first specific voltage control element 8sc to the first gate voltage control circuit 71. , And a voltage dividing output circuit 14 that divides the first gate stabilizing voltage V1dg into a plurality of other gate stabilizing voltages V2dg, V3dg,..., Vndg. Are applied to the Nth gate voltage control circuits 72... 7n as the Nth gate stabilization voltages V2dg, V3dg... Vndg, respectively, and a plurality of different stabilizations can be achieved with a simple circuit configuration having a relatively small number of parts. The voltage can be easily obtained.

  (8) If a plurality of voltage control elements 8g connected in series are provided in the voltage dividing output circuit 14 according to a preferred mode, the required voltage can be reduced by combining resistors with the voltage control elements 8g. Stabilization can be performed easily and reliably.

  (9) According to a preferred embodiment, if the gate voltage control circuit 71 is provided with the voltage adjustment circuit 15 that controls the gate application voltage V1g with the control voltage V1c, the magnitude (luminance) of the gate application voltage V1g. Can be easily and reliably realized by a simple circuit configuration, and optimization of the field emission lamps L1,... As the driving device 1 can be easily performed.

  (10) If FETs (field effect transistors) are used for the voltage control elements 8s..., 8sc, 8g... According to a preferred embodiment, the implementation can be carried out easily and at low cost by using relatively popular components (FETs). Can do.

1 is a circuit diagram including a block system showing the overall configuration of a field emission lamp driving device according to a preferred embodiment of the present invention; Specific circuit diagram showing the main configuration of the drive device, Principle circuit diagram for explaining the main components of the drive device, Principle circuit diagram for explaining other essential components of the drive device, Principle circuit diagram for explaining other essential components of the drive device, Principle circuit diagram for explaining other essential components of the drive device, Principle circuit diagram for explaining other essential components of the drive device,

  Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.

  First, the overall configuration of the field emission lamp driving apparatus 1 according to the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 shows a driving device 1 according to the present embodiment and a plurality of field emission lamps L1, L2,... Ln (n is an integer) driven (emitted) by the driving device 1. The field emission lamp L1 (the same applies to L2... Ln) is arranged inside the vacuum bulb with the cathode electrode, the gate electrode, and the anode electrode in order, with the cathode L1k, the gate L1g, and the anode serving as external terminals, respectively. Connected to L1a. Therefore, when a DC high voltage is applied to the anode L1a having the phosphor, electrons are emitted from the cathode electrode having the electron emission source, and this electron has a light emission principle that causes the phosphor of the anode electrode to emit light.

  On the other hand, the drive device 1 includes a step-up transformer 4 having a primary winding 4f and a secondary winding 4s. The primary winding 4f has a center tap, and this center tap is connected to the positive input terminal 21p via the power line H. Reference numeral 21n denotes a negative input terminal connected to the ground G. The illustrated driving device 1 is assumed to be mounted on an automobile. Therefore, DC 12 [V] of the battery voltage is input to the input terminals 21p and 21n. One end of the primary winding 4f is connected to the ground G via an FET 3a (between drain and source) serving as a switching element, and the other end of the primary winding 4f is connected to an FET 3b (between drain and source) serving as a switching element. To the ground G. Further, the signal circuit 2 and the control circuit 22 are connected between the power supply line H and the ground G.

  The signal circuit 2 has a function of generating and outputting the switching signals Sa and Sb that are pulse signals having a predetermined cycle. The switching signal Sa is applied to the gate of the FET 3a, and the switching signal Sb is applied to the gate of the FET 3b. In the illustrated example, the switching frequency of the switching signals Sa and Sb is set to 60 [kHz] in order to use the resonant circuit constituted by the step-up transformer 4 and the floating capacitance of the step-up transformer 4.

  In addition, the control circuit 22 has a function of controlling the entire driving device 1, and applies a control voltage V1c, V2c,... Vnc to at least gate voltage control circuits 71, 72,. , L2... Ln are provided with a dimming function for adjusting the luminance. At this time, as shown in FIG. 1, current detectors DX1, DX2,... DXn are connected in series to the field emission lamps L1, L2,... Ln, and the load detected by the current detectors DX1, DX2,. By giving the current detection result to the control circuit 22, feedback control is performed to correct the fluctuation of the load current of each field emission lamp L1, L2,... Ln. Further, although not shown in the drawings, a luminance operation unit that can be adjusted to an arbitrary luminance by being operated by the user may be adjusted (set) to an arbitrary luminance by the user. Therefore, the dimming function includes a stabilizing function (variation correcting function) for controlling the driving power (luminance) to be constant even when the load current flowing through each field emission lamp L1, L2,. Both of the dimming functions for operating the luminance operation unit (not shown) to arbitrarily change the luminance of the field emission lamps L1.

  On the other hand, the secondary winding unit 4s of the step-up transformer 4 is provided with a rectifier circuit 5 that rectifies the output voltage Vto output from the secondary winding unit 4s and outputs at least two DC output voltages Vsa and Vsg. Connecting. As shown in FIG. 1, a multiple voltage rectifier circuit 5p configured by combining a plurality of series-connected diodes Ds... And a plurality of series-connected capacitors Cs. In this case, a plurality of diodes Ds... Are sequentially connected in series from one end of the secondary winding portion 4s, and a plurality of capacitors Cs... Are sequentially connected in series from one end and the other end of the secondary winding portion 4s. Then, the connection points of the capacitors Ds connected from one end of the secondary winding portion 4s are sequentially connected to the connection points of the two diodes Ds..., And connected from the other end of the secondary winding portion 4s. The connection point between the capacitors Ds... Is connected to the connection point of the first stage between the diodes Ds... And then the connection point after the next stage between the capacitors Ds. Connect to the connection points sequentially. As a result, when the DC input voltage Vi of the power supply line H is 12 [V] and the turn ratio of the step-up transformer 4 is 90, an AC voltage of approximately 1.08 [kV] is output from the secondary winding 4s. Then, multiple voltage rectification is performed by the multiple voltage rectifier circuit 5p. In the illustrated example, the anode DC voltage Vsa of approximately 14.0 [kV] is obtained from the last-stage diode Ds, and this anode DC voltage Vsa is supplied to each field emission via the current detectors DX1. Applied to the anodes L1a ... L1n of the mold lamps L1 ... Ln. Further, from the predetermined diode Ds in the intermediate stage, a gate DC voltage Vsg of approximately 10.8 [kV] is obtained and applied to the voltage stabilizing circuit 6 described later.

  Thus, if the multiple voltage rectifier circuit 5p configured by combining the plurality of diodes Ds... Connected in series and the plurality of capacitors Cs. Both Vsg and anode DC voltage Vsa can be easily obtained. In addition, the combination with the step-up transformer 4 has an advantage that the DC voltages Vsg and Vsa having a required magnitude can be obtained easily and reliably.

  Further, as shown in FIG. 1, the driving device 1 according to the present embodiment receives the above-described gate DC voltage Vsg and outputs a plurality of gate stabilization voltages V1dg... Vndg, Each gate stabilization voltage V1dg... Vndg is input, and a plurality of gates are applied to the gates of the plurality of field emission lamps L1. Voltage control circuits 71... 7n.

  FIG. 2 shows a specific circuit example of the voltage stabilization circuit 6 and the gate voltage control circuit 71 (same for 72... 7n). In this case, the voltage stabilization circuit 6 includes a breakdown voltage input circuit 11, a voltage dividing circuit 12, a voltage feedback circuit 13, and a voltage dividing output circuit 14 broadly.

  The withstand voltage input circuit 11 is configured by sequentially connecting the drains and sources of a plurality (five examples) of FETs (voltage control elements) 8s... And 8sc in series, and between the gates of the FETs 8s. Are connected by bias resistors Rs. The gate DC voltage Vsg output from the above-described multiple voltage rectifier circuit 5p is input to the voltage input portion of the withstand voltage input circuit 11, that is, the drain of the uppermost FET 8s, and the minimum of the plurality of FETs 8s. The gate stabilization voltage V1dg... Is output from the source of the lowest-order FET 8sc to which the voltage is applied. Therefore, 8sc is a first specific FET (first specific voltage control element). In this case, the source of the first specific FET 8sc connected at the lowest level is connected to the ground G via a predetermined resistance element. The gate and drain of the uppermost FET 8s are connected by a bias resistor Rs.

  In this way, the voltage stabilizing circuit 6 is provided with the withstand voltage input circuit 11 in which a plurality of FETs 8s... And 8sc are sequentially connected in series, and the gate that outputs from the rectifier circuit 5 to the voltage input portion of the withstand voltage input circuit 11 The DC voltage Vsg is input, and the gate stabilization voltage V1dg is output from the FET (first specific FET) 8sc to which the minimum voltage is added among the plurality of FETs 8s..., 8sc, and the first specific FET 8sc is controlled. If the stabilization control signal Sc for stabilizing the gate stabilization voltage V1dg is applied to the input unit 8scg, the gate DC voltage Vsg may be increased to, for example, a high voltage of 10 [kV] or more due to fluctuations or the like. Even in such a case, the voltage can be divided by the plurality of FETs 8s,. In that the current is the reduction of use and parts of low withstand-voltage part, there is an advantage that can be improved in reliability and cost reduction.

  On the other hand, a stabilization control signal Sc for stabilizing the gate stabilization voltage V1dg is applied to the control input portion (gate) 8scg of the first specific FET 8sc. In the example circuit of FIG. 2, since the gate stabilization voltage V1dg is output from the source of the first specific FET 8sc, the gate stabilization voltage V1dg is divided by the voltage dividing circuit 12 including the resistors R1 and R2. The divided voltage Vp obtained in this way was used as the stabilization control signal Sc and applied (feedback) to the control input part (gate) 8scg of the first specific FET 8sc via the voltage feedback circuit 13. The voltage feedback circuit 13 includes a feedback transistor 11x having a collector and an emitter connected between a voltage output portion (source) 8scs and a control input portion (gate) 8scg of the first specific FET 8sc, and a divided voltage Vp (stabilization control). A Zener diode Dtp is provided for applying the signal Sc) to the base of the feedback transistor 11x. Ds is a temperature compensation diode connected in series to the Zener diode Dtp, and Rs is a bias resistor connected between the emitter and collector of the feedback transistor 11x.

  In this way, the voltage stabilizing circuit 6 divides the gate stabilizing voltage V1dg output from the first specific FET 8sc into the voltage stabilizing circuit 6, and the divided voltage Vp obtained from the voltage dividing circuit 12 is used as a stabilization control signal. If the voltage feedback circuit 13 provided to the control input unit (gate) 8scg of the first specific FET 8sc is provided as Sc, there is an advantage that it can be easily realized by a simple circuit configuration with a small number of parts when realizing voltage stabilization. is there. In addition, the voltage feedback circuit 13 is provided with a feedback transistor 11x in which a collector and an emitter are connected between the voltage output section (source) 8scs and the control input section (gate) 8scg of the first specific FET 8sc. If the divided voltage Vp is applied to the base of the feedback transistor 11x via the Zener diode Dtp, the voltage feedback circuit 13 for realizing voltage stabilization with respect to the target (required) high voltage. There is an advantage that can be configured easily and reliably.

  On the other hand, the voltage stabilization circuit 6 converts the gate stabilization voltage (first gate stabilization voltage) V1dg output from the voltage output unit 8scs of the first specific FET 8sc into the first gate voltage control circuit (first gate voltage). And a voltage dividing output circuit 14 that divides the first gate stabilizing voltage V1dg into a plurality of other gate stabilizing voltages V2dg, V3dg... Vndg. The gate stabilization voltages V2dg, V3dg,..., Vndg (N is 2, 3,... N, and n is an integer) are applied to the Nth gate voltage control circuits 72. To do.

  In this case, the voltage dividing output circuit 14 is configured by sequentially connecting the drains and sources of a plurality of FETs (voltage control elements) 8g... And between the gates of the FETs 8s. , R12, R13, R14. The voltage dividing output circuit 14 basically generates a gate stabilization voltage other than the first gate stabilization voltage V1dg, that is, a second gate stabilization voltage V2dg... Nth gate stabilization voltage Vndg. It has a function to output. In this case, the second gate stabilization voltage V2dg... Nth gate stabilization voltage Vndg is output from the source of each FET 8g. In FIG. 2, Cs... Indicates an output stabilization capacitor.

  Thus, the first gate stabilization voltage V1dg output from the voltage output unit (source) 8scs of the first specific FET 8sc is applied to the first gate voltage control circuit 71 to the voltage stabilization circuit 6, and the first gate Voltage dividing output circuit 14 that divides the stabilization voltage V1dg into a plurality of other gate stabilization voltages V2dg, V3dg,..., Vndg. If the gate stabilization voltages V2dg, V3dg... Vndg are respectively applied to the Nth gate voltage control circuits 72... 7n, a plurality of different stabilization voltages can be easily obtained by a simple circuit configuration with a relatively small number of parts. There are benefits to be gained. Further, if the voltage dividing output circuit 14 is provided with a plurality of FETs 8g connected in series, the required voltage can be easily and reliably stabilized by combining resistors with the FETs 8g.

  On the other hand, the gate voltage control circuit 71 (the same applies to the other gate voltage control circuits 72... 7n) includes a voltage adjustment circuit 15 as shown in FIG. 2, and is controlled by a control voltage V1c applied from the control circuit 22. A function of controlling the gate application voltage V1g is provided. The gate voltage control circuit 71 includes an FET 32, and the first gate stabilization voltage V1dg applied from the voltage stabilization circuit 6 is applied to the drain of the FET 32 via the resistor Ri. Further, the gate application voltage V1g is output from the source of the FET 32, and is applied to the gate L1g of the field emission lamp L1 through the resistor Ro. At this time, the source of the FET 32 is connected to the ground G through a series circuit of resistors R20, R21, and R22. The voltage at the connection point between the resistors R20 and R21 is fed back through the voltage feedback circuit 13t similar to the voltage feedback circuit 13 described above, thereby stabilizing the voltage. In the voltage feedback circuit 13t, 11z represents a feedback transistor, Dtp represents a Zener diode, Ds represents a temperature compensation diode, and Rs represents a bias resistor. Further, the drain-source of the FET 33 is connected to both ends of the resistor R22, and the control voltage V1c from the control circuit 22 is applied to the gate of the FET 33. In the figure, Ci and Co indicate voltage stabilizing capacitors.

  As described above, if the gate voltage control circuit 71 is provided with the voltage adjustment circuit 15 that controls the gate application voltage V1g with the control voltage V1c, the magnitude (luminance) of the gate application voltage V1g is adjusted (adjusted). (Light control) can be realized easily and reliably with a simple circuit configuration, and there is an advantage that optimization as the driving device 1 for the field emission lamps L1.

  Next, the operation (function) of the field emission lamp driving apparatus 1 according to the present embodiment will be described with reference to FIGS.

  Assume that a DC input voltage Vi (= 12 [V]) is applied to the positive input terminal 21p and the negative input terminal 21n. In the signal circuit 2, switching signals Sa and Sb are generated based on the set on / off timing, and are applied to the gates of the FETs 3a and 3b, respectively. Accordingly, the FETs 3a and 3b are alternately turned on / off, and the input current Vi flows through the primary winding portion 4f by applying the switched input voltage Vi.

  The output voltage Vto is output from the secondary winding portion 4s of the step-up transformer 4, and the multiple voltage rectification is performed by the multiple voltage rectifier circuit 5p. As a result, the anode DC voltage Vsa of approximately 14.0 [kV] is obtained from the diode Ds at the final stage, and the anode L1a of each field emission lamp L1... Ln via the current detectors DX1. ... Is applied to L1n, and a gate DC voltage Vsg of about 10.8 [kV] is obtained from the predetermined diode Ds in the intermediate stage, and the maximum voltage of the withstand voltage input circuit 11 in the voltage stabilizing circuit 6 described above is obtained. It is given to the drain of the upper FET 8s.

  Even when the gate direct-current voltage Vsg reaches a high voltage due to fluctuations or the like, the voltage-proof input circuit 11 can divide the voltage by the plurality of FETs 8s. When realizing high voltage control, reliability can be improved and costs can be reduced by using parts with low withstand voltage and reducing the number of parts.

  The breakdown voltage input circuit 11 will be described with reference to the principle diagram shown in FIG. As illustrated, the gate DC voltage Vsg is set to 10.8 [kV] when configured as a driving device 1 for lamps mounted on an automobile. In this case, assuming that the fluctuation of the battery voltage is 6 to 16 [V] and the gate applied voltage V1g output from the voltage stabilizing circuit 6 is 3.7 [kV], the fluctuation is 4.5 to 12 [kV]. And a high voltage of 7 [kV] at maximum is applied to the withstand voltage input circuit 11. Therefore, in this embodiment, all the FETs 8s... Are connected in series with the first specific FET 8sc, which is the original FET, and only the stabilization control signal Sc is applied to the gate of the first specific FET 8sc. The voltages applied to the FETs 8s..., 8sc were made equal. As a result, a high voltage of 7 [kV] can be dealt with by connecting in series five or more FETs 8s (including the first specific FET 8sc) having a withstand voltage of 1.5 [kV]. The voltages applied to the FETs 8s..., 8sc are about 1.3 [kV]. In FIG. 3, Rr indicates an equivalent resistance between the source of the first specific FET 8sc and the ground G.

  Further, the stabilization control signal Sc described above is generated by the voltage dividing circuit 12 and the voltage feedback circuit 13, and is given to the gate (control input unit) 8scg of the first specific FET 8sc. FIG. 4 shows a principle diagram of the voltage dividing circuit 12 and the voltage feedback circuit 13. As shown in FIG. 4, when the output from the voltage stabilization circuit 6, that is, the gate stabilization voltage V1dg output from the source of the first specific FET 8sc fluctuates, the voltage dividing resistor R1 constituting the voltage dividing circuit 12 The voltage at the connection point p1 of R2 also varies. Therefore, the voltage across the resistor R1 also varies, and the currents i1 and i2 also vary in FIG. As a result, the voltage applied to the gate 8scg of the first specific FET 8sc also varies. Since this voltage functions as the stabilization control signal Sc and acts to correct the fluctuation of the gate stabilization voltage V1dg, the gate stabilization voltage V1dg that is the output voltage of the voltage stabilization circuit 6 is stabilized. .

  On the other hand, the gate stabilization voltage V1dg becomes the first gate stabilization voltage V1dg applied to the first gate voltage control circuit 71, but is applied to the second gate voltage control circuit 72... The Nth gate voltage control circuit 7n. The second gate stabilization voltage V2dg... The Nth gate stabilization voltage Vndg is generated based on the voltage dividing output circuit. FIG. 5 is a principle diagram showing a generation system of the second gate stabilization voltage V2dg applied to the second gate voltage control circuit 72. As shown in FIG. 5, an FET (voltage control element) 8g constituting the voltage dividing output circuit 14 is connected in series between the first specific FET 8sc that outputs the first gate stabilization voltage V1dg and the ground G, that is, When the drain of the FET 8g is connected to the voltage output part (source) 8sgs of the first specific FET 8sc, and the first gate stabilization voltage V1dg is connected to the ground G through the series connection of the resistors R10 and R11, the resistor The voltage Vg at the connection point p2 between R10 and R11 is Vg = V1dg × (R11 / (R10 + R11)), which is a value obtained by dividing V1dg by the resistance value ratio of the resistors R10 and R11. On the other hand, when the gate of the FET 8g is connected to the connection point p2 and the source of the FET 8g is the second gate stabilization voltage V2dg of the voltage stabilization circuit 6, the voltage Vg at the connection point p2 is substantially equal. In this case, since the first gate stabilization voltage V1dg is stabilized as described above, the voltage Vg at the connection point p2 obtained by dividing the first gate stabilization voltage V1dg is also stabilized. Is planned. As a result, the target second gate stabilization voltage V2dg can be automatically stabilized.

  Therefore, if the voltage dividing output circuit 14 is used, the third gate stabilization voltage V3dg... Nth gate stabilization voltage Vndg can be generated in the same manner based on the same principle. FIG. 6 shows a generation system including the third gate voltage V3dg in a principle diagram with respect to FIG. As shown in FIG. 6, in addition to the second gate voltage V2dg, a circuit unit similar to that for generating the second gate voltage V2dg should be added even when the third gate voltage V3dg is generated. Thus, the third gate voltage V3dg can be generated. In this case, if the magnitudes of the resistors R10, R11, R12 are changed, the magnitudes of the second gate voltage V2dg and the third gate voltage V3dg can be arbitrarily changed (set).

  As described above, when the voltage dividing output circuit 14 is used, a plurality of different stabilization voltages can be easily obtained by a simple circuit configuration with a relatively small number of parts, and a plurality of series-connected FETs 8g. For example, the required voltage can be stabilized easily and reliably by combining resistors with the FETs 8g. In FIG. 6, p2 is a connection point between the resistors R10 and R11, p3 is a connection point between the resistors R11 and R12, and Rd is an equivalent resistance between the source of the FET 8g that outputs the third gate voltage V3dg and the ground G.

  On the other hand, the gate voltage control circuits 71... Function as follows. FIG. 7 shows a principle diagram of the first gate voltage control circuit 71. The first gate stabilization voltage V1dg is input to the first gate voltage control circuit 71 (the other second gate voltage control circuit 72... Nth gate voltage control circuit 7n is also the same). At this time, since the first gate voltage control circuit 71 includes the voltage feedback circuit 13t described above, the first gate voltage control circuit 71 outputs a gate applied voltage V1g whose voltage is stabilized, and a field emission type. Applied to the gate L1g of the lamp L1. In this case, since the first gate voltage control circuit 71 includes the voltage feedback circuit 13t, the voltage at the connection point p4 between the resistors R20 and R21 is fed back to the gate of the FET 32, and the gate applied voltage V1g is stabilized. .

  Further, since the first gate voltage control circuit 71 includes the voltage adjustment circuit 15 that controls the gate application voltage V1g by the control voltage V1c, the magnitude of the gate application voltage V1g can be increased by changing the magnitude of the control voltage V1c. The brightness (brightness) adjustment (dimming control) can be easily and reliably realized with a simple circuit configuration. In this case, the control voltage V1c is applied from the control circuit 22. The control voltage V1c includes the control voltage V1c based on the detection result of the load current detected by the current detection unit DX1 connected in series with the field emission lamp L1. As a result, even if the luminance of the field emission lamp L1 varies due to some disturbance, feedback control is performed so that the luminance is always maintained constant. Further, since the control voltage V1c includes a control voltage V1c for the user to operate the brightness operation unit and adjust (set) the brightness to an arbitrary brightness, the control voltage V1c has an arbitrary brightness based on the control voltage V1c. Set to

  Therefore, according to the driving apparatus 1 according to the present embodiment, in addition to eliminating variations in light emission between the plurality of field emission lamps L1... Having the same standard, a plurality of standards (types) having different standards (types) can be obtained. Even when the field emission lamps L1 are caused to emit light at the same time, the field emission lamps L1 can be caused to emit light with an accurate luminance so as to satisfy the original standard. Therefore, it can be applied to illumination systems in various fields including a plurality of various field emission lamps L1,. Further, when a plurality of field emission lamps L1... Having the same standard are caused to emit light and a plurality of field emission lamps L1. The drive device 1 can cope with it accurately. Therefore, it is possible to effectively reduce the number of parts, further reduce the size of the entire device, reduce power consumption, and reduce costs. In particular, the illumination system for automobiles equipped with lamps of various standards (types). It is optimal to apply to.

  As mentioned above, although preferred embodiment was described in detail, this invention is not limited to such embodiment, It does not deviate from the summary of this invention in a detailed structure, a shape, a raw material, quantity, a numerical value, etc. It can be changed, added, or deleted arbitrarily. For example, although the case where the multiple voltage rectifier circuit 5p is used as the rectifier circuit 5 is illustrated, other rectifier circuits are not excluded. Further, although an isolation type transformer is used as the step-up transformer 4, a single-winding transformer may be used, and the kind of the transformer is not limited. Furthermore, although the example which used FET (field effect transistor) was shown as voltage control element 8s ..., 8sc, 8g ..., use of the other voltage control element which exhibits the same function is not excluded. However, the use of FETs has the advantage that they can be implemented easily and at low cost by using relatively popular parts (FETs). On the other hand, the withstand voltage input circuit 11 is not necessarily provided as long as an FET or the like having high withstand voltage performance can be used. In addition, the detailed circuit configuration can be replaced by another circuit configuration as long as the same function is exhibited. In FIG. 7, the resistors R21 and R22 can be deleted. In this case, the drain of the FET 33 may be directly connected to the connection point p4.

  The drive device 1 according to the present invention can be used for field emission lamps in various applications such as a field emission illumination lamp (FEL) and a field emission display device (FED). The name does not matter.

  1: driving device, 2: signal circuit, 3: switching circuit, 3a: switching element, 3b: switching element, 4: step-up transformer, 5: rectifier circuit, 5p: multiple voltage rectifier circuit, 6: voltage stabilization circuit, 71 ... 7n: gate voltage control circuit, 8s ... voltage control element (FET), 8sc: first specific voltage control element (first specific FET), 8scg: control input unit (gate), 8scs: voltage output unit (source) , 8g...: Voltage control element (FET), 11: breakdown voltage input circuit, 11x: feedback transistor, 12: voltage dividing circuit, 13: voltage feedback circuit, 14: voltage dividing output circuit, 15: voltage adjusting circuit, Sa : Switching signal, Sb: switching signal, Sc: stabilization control signal, Vi: DC input voltage, Vto: output voltage, Vsg: DC voltage for gate, Vsa: DC voltage for anode V1dg ... Vndg: gate stabilization voltage, V1g ... Vng: gate applied voltage, Vp: divided voltage, V1c ...: control voltage, L1 ... Ln: field emission lamp, L1g ... Lng: gate, L1a ... Lna: Anode, Ds ...: Diode, Dtp: Zener diode, Cs ...: Capacitor

Claims (9)

  A signal circuit that outputs a switching signal, a switching circuit that switches a DC input voltage by controlling on / off of the switching element by the switching signal, a step-up transformer that steps up the switched input voltage, and an output voltage of the step-up transformer And a rectifier circuit that outputs at least a DC voltage for the gate to be supplied to the gate of the field emission lamp and a DC voltage for the anode to be supplied to the anode. A voltage stabilizing circuit for inputting the gate DC voltage and outputting a plurality of gate stabilizing voltages, and for each gate stabilizing voltage being input, and at least a gate applied voltage whose voltage is adjusted. Multiple gate voltages that are output and applied to the gates of multiple field emission lamps, respectively Field emission lamp driving apparatus characterized by comprising; and a control circuit.   2. The field emission lamp driving device according to claim 1, wherein the rectifier circuit uses a multiple voltage rectifier circuit configured by combining a plurality of diodes connected in series and a plurality of capacitors connected in series.   The voltage stabilization circuit includes a voltage-proof input circuit in which a plurality of voltage control elements are sequentially connected in series, and the gate DC voltage output from the rectifier circuit is input to a voltage input portion of the voltage-proof input circuit. And outputting the gate stabilization voltage from a voltage control element (first specific voltage control element) to which a minimum voltage is added among the plurality of voltage control elements, and a control input unit of the first specific voltage control element 3. The field emission lamp driving device according to claim 1, further comprising a stabilization control signal for stabilizing the gate stabilization voltage.   The voltage stabilization circuit divides the gate stabilization voltage output from the first specific voltage control element, and a divided voltage obtained from the voltage division circuit as the stabilization control signal. 4. The field emission lamp driving device according to claim 3, further comprising a voltage feedback circuit applied to a control input section of the one specific voltage control element.   The voltage feedback circuit includes a feedback transistor in which a collector and an emitter are connected between a voltage output unit of the first specific voltage control element and the control input unit, and a divided voltage obtained from the voltage divider circuit is converted into a Zener diode. 5. The field emission type lamp driving device according to claim 4, wherein the field emission type lamp driving device is applied to the base of the feedback transistor via a base.   The voltage stabilization circuit outputs the gate stabilization voltage (first gate stabilization voltage) output from the voltage output unit of the first specific voltage control element to a first gate voltage control circuit (first gate voltage). Control circuit) and a voltage dividing output circuit for dividing the first gate stabilizing voltage into a plurality of other gate stabilizing voltages, and each gate stabilizing voltage obtained from the divided output circuit 6. The field emission type according to claim 4, wherein the Nth gate voltage control circuit is provided as a stabilization voltage for the Nth gate (N is 2, 3... N, and n is an integer). Lamp drive device.   7. The field emission lamp driving apparatus according to claim 6, wherein the divided voltage output circuit includes a plurality of voltage control elements connected in series.   The field emission lamp driving device according to claim 1, wherein the gate voltage control circuit includes a voltage adjustment circuit that controls the gate applied voltage with a control voltage.   9. The field emission lamp driving apparatus according to claim 3, wherein the voltage control element is an FET (field effect transistor).

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