JP4061312B2 - Light emitting diode driving semiconductor device and light emitting diode driving device - Google Patents

Description

  The present invention relates to a semiconductor device for driving a light-emitting diode, and more particularly to a semiconductor device for driving a light-emitting diode suitable for an LED lighting device using light-emitting diodes connected in parallel. Further, it relates to a light emitting diode driving device using the same.

  When the light emitting diodes are driven in parallel, the output luminance variation caused by the forward voltage variation in each light emitting diode becomes an important issue. As a method for reducing this variation, a constant current circuit using a current mirror circuit has been mainly used.

  FIG. 18 is a circuit diagram showing a conventional light emitting diode driving device disclosed in Patent Document 1. In FIG. This circuit includes a plurality of LED array circuits 100 formed by connecting a plurality of light emitting diodes 102 and 103, a current limiting resistor 101, and a bipolar transistor 104 in series. Furthermore, the constant current circuit 120 having the bipolar transistor 121 that constitutes each current mirror circuit together with the bipolar transistor 104 of each LED array circuit 100, and each current mirror circuit so as to switch the bipolar transistor 104 of each LED array circuit 100 together. Switching means 130 having a bipolar transistor 131 connected to the. A constant voltage is supplied from the constant voltage circuit 110 to the constant current circuit 120.

  Due to the operation of the current mirror circuit configured by the bipolar transistor 121 of the constant current circuit 120 together with the bipolar transistor 104 of each LED array circuit 100, the same current as the constant current of the constant current circuit 120 flows to each LED array circuit 100. The light emitting diodes 102 and 103 of each LED array circuit 100 are driven to emit light. The switching circuit 130 switches the bipolar transistors 104 together when the bipolar transistors 131 connected to the current mirror circuits are switching-controlled by the dimming control output from the dimming circuit 140.

  According to the conventional LED driving device, the bipolar transistor 121 of the constant current circuit 120 and the bipolar transistor 104 of the LED array circuit 100 connected in parallel are switched under the current mirror action of each current mirror circuit. As a result, the LED array circuits 100 connected in parallel are driven with a constant current, so that even if the forward voltages of the light emitting diodes 102 and 103 vary, the light emission luminance does not vary.

  FIG. 19 is a circuit diagram showing another conventional LED driving device disclosed in Patent Document 2. In FIG. This conventional example includes an LED array circuit 201 formed by connecting two or more LED series circuits 202 each having a plurality of LEDs connected in series, and a constant current circuit 203 connected in series to each LED series circuit 202. Is provided. The constant current circuit 203 allows a constant current to flow through the LED string regardless of the magnitude of the input voltage of each LED series circuit 202. The single-phase AC power supply 204, the rectifier 205, and the constant voltage regulator 206 constitute a power supply unit. The DC voltage adjusted by the constant voltage regulator 206 after rectifying the power supply voltage of the single-phase AC power supply 204 by the rectifier 205 is the LED array circuit. 201 is applied. The power supply unit is controlled by the control unit 207 so that the burden voltage of the constant current circuit 203 is smaller than the forward voltage of the LED string of the LED series circuit 202.

  The constant voltage regulator 206 is a step-up type with a step-up chopper and is controlled by the control means 207 to adjust and output a constant voltage supplied to the LED array circuit 201. The comparison unit 208 detects the minimum value of the burden voltage of the circuit element 203 of each LED series circuit 202 and outputs the detected minimum value to the control unit 207.

The control means 207 controls the constant voltage regulator 206 so that the burden voltage of the constant current circuit 203 is smaller than the forward voltage of the LED string of the LED series circuit 202. In this case, since the burden voltage of each constant current circuit 203 varies, the minimum value of the input voltages of each constant current circuit 203 detected by the comparison means 208 is the order of the LED strings in the LED series circuit 202. The constant voltage regulator 206 is controlled so as to be smaller than the directional voltage. Further, the control means 207 controls the minimum value of the burden voltage of the constant current circuit 203 to substantially zero when the forward voltage of the LED row is established and each LED series circuit 202 is lit.
Japanese Patent Laid-Open No. 2003-1000047 Japanese Patent Laid-Open No. 2002-8409

  However, the light-emitting diode driving device disclosed in Patent Document 1 has the following problems. That is, since a current limiting resistor is connected to each LED array circuit, power loss is large. In addition, since a bipolar transistor is connected to each light emitting diode circuit to form a constant current circuit by a current mirror circuit, power loss occurs in the bipolar transistor of each LED array circuit, and the light emission efficiency is lowered.

  Further, the light emitting diode driving device disclosed in Patent Document 2 has the following problems. That is, control is performed so that the minimum value among the burden voltages of the circuit elements connected to each LED array circuit is substantially zero, but the burden voltage is applied to the circuit elements connected to other LED arrays. As a result, power loss occurs in these circuit elements. In addition, since a chopper circuit is used when converting AC voltage to DC, power loss occurs in this circuit. Further, since there is no means for changing the value of the current flowing through each LED array circuit, it does not have a dimming function.

  In view of the above problems, the present invention provides a light emitting diode driving semiconductor device that can control light intensity and chromaticity with a simple configuration and has low power loss even if there is a variation in forward voltage depending on the LED array. The purpose is to provide.

  A semiconductor device for driving a light emitting diode according to the present invention includes a light emitting diode block having a plurality of light emitting diode arrays formed by connecting a plurality of light emitting diodes in series, a choke coil connected in series to the light emitting diode block, and A plurality of diodes for supplying back electromotive force generated in the choke coil to the plurality of light emitting diode arrays, a rectifier circuit that rectifies an AC voltage of an AC power source and applies the AC voltage to the light emitting diode block and the choke coil; The switching drive circuit in a light emitting diode driving device comprising a switching drive circuit for supplying current to the light emitting diode block is configured.

  In order to solve the above problems, a semiconductor device for driving a light emitting diode according to the present invention includes a switching element block and a control circuit block, and the switching element block includes a plurality of main switching elements connected in series for each light emitting diode array. And at least one junction type FET connected to correspond to the main switching element, and the control circuit block is connected to the input terminal connected to the other end of the junction type FET and to the input terminal. A reference voltage terminal that outputs a reference voltage, an input voltage detection circuit that detects a voltage obtained by rectifying the AC voltage, and a predetermined voltage for the plurality of main switching elements when an output voltage of the input voltage detection circuit exceeds a predetermined value. Starts an ON operation based on intermittent ON / OFF control at the oscillation frequency, and outputs the output voltage of the input voltage detection circuit. A start / stop circuit that stops when less than a predetermined value, a plurality of current detection circuits that detect currents flowing through the plurality of main switching elements, and a detection signal from each of the current detection circuits, And a control circuit that controls the off operation so that the flowing current is constant.

  By configuring as described above, in each light emitting diode array, when the switching element is in the on state, current flows in the direction of the choke coil → the light emitting diode → the switching element, and when the switching element is in the off state, A current flows through a circuit loop composed of a choke coil, a light emitting diode, and a diode in the direction of the choke coil → the light emitting diode → the diode, and operates like a step-down chopper. Therefore, the power conversion efficiency is high, the number of parts is small, the size is small, and the current flowing to each light emitting diode array can be controlled with a constant current without depending on the fluctuation of the input voltage or the forward voltage variation of each light emitting diode array. A light emitting diode driving device with a constant degree can be realized. In addition, since the voltage at which the drive circuit starts / stops is defined by an arbitrary voltage of the rectified input voltage, the ratio between the period during which current flows and the period during which current does not flow can be adjusted in one cycle, so that the luminous intensity is kept constant. The light emitting diode driving device can be realized.

  According to the present invention, it is possible to realize a small-sized light emitting diode driving device capable of controlling light intensity and chromaticity with a simple configuration even when there is a variation in forward voltage depending on the LED array with high power conversion efficiency. it can.

  In the light emitting diode driving semiconductor device configured as described above, the switching element block has a plurality of control terminals, a plurality of high potential side terminals, and a low potential side terminal, and is paired with the output terminal of the junction FET. One output terminal of the main switching element is connected, each output terminal of the control circuit block and each control terminal of the plurality of main switching elements are connected to each control terminal, and the junction type FET is connected to the high potential side terminal Input terminal of the control circuit block is connected to a connection portion of the output terminal of the main switching element paired with the output terminal of the junction FET, and the plurality of main terminals are connected to the low potential side terminal. The other output terminal of the switching element and the ground terminal of the control circuit block may be connected.

  Alternatively, the switching element block has a plurality of control terminals, a plurality of high potential side terminals, and a low potential side terminal, and each of the output terminals of the control circuit block and the plurality of main switching elements are connected to the control terminals. Each control terminal is connected, one output terminal of the plurality of main switching elements is connected to each high potential side terminal, the input terminal of the junction FET is connected to one of the high potential side terminals, The input terminal of the control circuit block is connected to the output terminal of the junction FET, and the other output terminal of the plurality of main switching elements and the ground terminal of the control circuit block are connected to the low potential terminal. Can do.

  Alternatively, the switching element block has a plurality of control terminals, a rectified voltage source terminal, a plurality of high potential side terminals, and a low potential side terminal, and each output terminal of the control circuit block and the plurality The control terminals of the main switching element are connected, the output terminal of the rectifier circuit and the input terminal of the junction FET are connected to the rectified power supply terminal, and the input terminal of the control circuit block is connected to the output terminal of the junction FET. Are connected, one output terminal of the plurality of main switching elements is connected to each high potential side terminal, the other output terminal of the plurality of main switching elements and the ground terminal of the control circuit block to the low potential terminal Can be configured to be connected.

  According to the above configuration, the high voltage applied to the high potential side of the junction FET is pinched off at a low voltage on the low potential side of the junction FET due to the pinch-off effect of the junction FET. As a result, since power can be supplied from the switching element block to the control circuit, a power loss due to a starting resistor or the like is reduced, and a light emitting diode driving device with high power conversion efficiency can be realized.

  In the light emitting diode driving semiconductor device having any one of the above configurations, it is preferable that the control circuit block has a regulator inserted between the input terminal and the reference voltage terminal.

  With this configuration, the reference voltage during operation of the control circuit can be kept constant, so that stable switching element control can be realized.

  In the semiconductor device for driving a light emitting diode having any one of the above-described configurations, the plurality of current detection circuits detect currents flowing through the switching elements by comparing ON voltages of the plurality of main switching elements with a detection reference voltage. It is preferable to do.

  By detecting the ON voltage of each switching element of the switching element block in this way, it is possible to detect the current of each switching element with reduced power loss, that is, to detect the peak value of the current flowing through each light emitting diode array, and to achieve power conversion efficiency. Can realize a light emitting diode driving device.

  In the light emitting diode driving semiconductor device having any one of the configurations described above, the plurality of current detection circuits include a plurality of pairs, each of which has a control terminal and a high potential side terminal connected in parallel to the plurality of main switching elements. A sub-switching element and a resistor connected in series to the low-potential side of each sub-switching element, wherein a current flowing through the sub-switching element is smaller than a current flowing through the main switching element, and the main switching element It is preferable to set a constant current ratio to the flowing current, and to detect the current of each main switching element by comparing the voltage across each resistor with a detection reference voltage.

  According to this configuration, since a large current is not directly detected by a resistor, a current detection of a switching element with reduced power loss, that is, detection of a peak value of a current flowing through each light emitting diode array, and a light emitting diode with high power conversion efficiency A drive device can be realized.

  The semiconductor device for driving a light emitting diode having any one of the above configurations further includes an external detection terminal connected to the plurality of current detection circuits, and changes a value of the detection reference voltage input to the external detection terminal. Thus, it is preferable that the ON period in the intermittent ON / OFF control of the main switching element can be changed by an external signal, and thereby the constant current level flowing through the light emitting diode block can be adjusted.

  With this configuration, it is possible to realize a light-emitting diode driving device having a function of controlling the luminous intensity and chromaticity of the entire light-emitting diode block and having high power conversion efficiency.

  Alternatively, each of the external switching terminals connected to the plurality of current detection circuits further includes an intermittent connection of the main switching element by changing a value of the detection reference voltage input to the plurality of external detection terminals. It is preferable that the on period in the on / off control can be changed by an external signal, and the constant current level flowing through the light emitting diode array can be individually adjusted.

  According to this configuration, since it has a function of controlling the light intensity and chromaticity of each light emitting diode array, it is possible to realize a light emitting diode driving device having a more complicated light control function and high power conversion efficiency.

  In the semiconductor device for driving a light emitting diode having any one of the above configurations, the input voltage detection circuit is connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block. It is preferable that the two resistors are provided, and a comparator in which a DC voltage divided by resistance division by the two resistors is input to the + terminal and a preset reference voltage is input to the − terminal.

  With this configuration, it is possible to realize a light emitting diode driving device that can accurately define the period of light emission and the period of light extinction during a double period of the frequency of the AC power supply (100 Hz / 120 Hz when a general commercial power supply is used).

  Alternatively, the input voltage detection circuit includes two resistors connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block, and a resistor formed by the two resistors. A voltage at which the switching element is started / stopped by changing the reference voltage according to an external signal, and a comparator in which a DC voltage divided by the division is input to the + terminal and a reference voltage is input to the − terminal Is preferably adjustable.

  With this configuration, it is possible to easily adjust the start / stop voltage, and it is possible to realize a light emitting diode driving device with high power conversion efficiency capable of adjusting luminous intensity.

  Alternatively, the input voltage detection circuit includes two resistors connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block, and a resistor formed by the two resistors. HI which is an external terminal connected to each of the first and second comparators to which the DC voltage divided by the division is input to one input terminal and the other input terminal of the first and second comparators. A NOR circuit having a level input terminal and a LOW level input terminal, and an output terminal of the first and second comparators connected thereto, the first comparator having a + terminal connected to the LOW level input terminal; The DC voltage divided by the resistance division is input to the terminal, and the input voltage VL that defines the lower limit of the start level of the start / stop circuit is set to In the second comparator, the HI level input terminal is connected to a negative terminal, a DC voltage divided by the resistance division is input to a positive terminal, and the start / stop circuit of the second comparator It is preferable that the comparison result with respect to the input voltage VH that defines the upper limit of the activation level is output and the activation / deactivation can be controlled by arbitrary voltages VH and VL.

  With this configuration, since the level of the start voltage and the stop voltage in one cycle can be set individually, it is possible to realize a light emitting diode driving device with high power conversion efficiency capable of more complex light intensity adjustment.

  In the light emitting diode driving semiconductor device having the above configuration, the low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block, and the input voltage detection circuit is connected to the low potential side output terminal of the junction FET. Can be configured to include a comparator connected to the + terminal and a preset reference voltage input to the-terminal.

  According to this configuration, since the input voltage is not directly detected by the resistor, a light emitting diode driving device having an input voltage detection function with high power conversion efficiency can be realized.

  Alternatively, the low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block, and the input voltage detection circuit is configured such that the low potential side output terminal of the junction FET is connected to the + terminal and the reference voltage Can be configured such that a voltage at which the switching element is started / stopped can be adjusted by changing the reference voltage with an external signal.

  With this configuration, it is possible to easily adjust the start / stop voltage, and it is possible to realize a light emitting diode driving device with high power conversion efficiency capable of adjusting luminous intensity.

  Alternatively, the low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block, and the input voltage detection circuit has the low potential side output terminal of the junction FET connected to one input terminal. HI level input terminal and LOW level input terminal which are external terminals respectively connected to the other input terminals of the first and second comparators, and the first and second comparators A NOR circuit connected to the output terminal of the first FET, the first comparator has a + terminal connected to the LOW level input terminal, a negative terminal connected to the low potential side output terminal of the junction FET, The comparison result with respect to the input voltage VL that defines the lower limit of the start level of the start / stop circuit is output, and the second comparator has a HI level input terminal at a negative terminal. Then, the low potential side output terminal of the junction FET is connected to the + terminal, and the comparison result with respect to the input voltage VH that defines the upper limit of the start level of the start / stop circuit is output, and arbitrary voltages VH and VL are output. Thus, the start / stop can be controlled.

  With this configuration, since the level of the start voltage and the stop voltage in one cycle can be set individually, it is possible to realize a light emitting diode driving device with high power conversion efficiency capable of more complex light intensity adjustment.

  The light emitting diode driving semiconductor device having the above configuration includes the input voltage detection circuit and the start / stop circuit corresponding to each of the light emitting diode arrays, and the start / stop can be controlled with arbitrary voltages VH and VL. There can be a certain configuration.

  With this configuration, since the level of the start voltage and the stop voltage in one cycle can be set individually for each light emitting diode array, a light emitting diode driving device with high power conversion efficiency capable of more complex light intensity adjustment can be realized.

  In the light emitting diode driving semiconductor device having any one of the above configurations, a soft start circuit is provided between the external detection terminal and the current detection circuit, and the soft start circuit inputs a start signal from the start / stop circuit. Then, it is preferable that the detection reference voltage is output so as to gradually increase until reaching a certain value.

  With this configuration, it is possible to realize a light-emitting diode driving device that can prevent an inrush current that occurs at startup and can gradually increase the luminous intensity of each light-emitting diode array.

  Moreover, it is preferable to provide an overheat protection function.

  With this configuration, the safety of the light-emitting diode driving device can be improved.

  A light emitting diode driving device of the present invention includes a light emitting diode block having a plurality of light emitting diode arrays formed by connecting a plurality of light emitting diodes in series, a choke coil connected in series to the light emitting diode block, A plurality of diodes for supplying back electromotive force generated in the choke coil to the plurality of light emitting diode arrays; a rectifier circuit that rectifies an AC voltage of an AC power supply and applies the rectified voltage to the light emitting diode block and the choke coil; And a switching drive circuit for supplying a current to the diode block, wherein the switching drive circuit is constituted by the light-emitting diode driving semiconductor device having any one of the above-described configurations.

  With this configuration, similar to the effect obtained by the above-described semiconductor device for driving a light emitting diode, the power conversion efficiency is high, the number of parts is small, and the size is small. In addition, the current flowing through each light emitting diode array can be controlled with a constant current, and a light emitting diode driving device capable of freely controlling chromaticity can be realized. In addition, since the voltage at which the drive circuit starts / stops is defined by an arbitrary voltage of the rectified input voltage, the ratio of the period during which current flows and the period during which current does not flow can be adjusted in one cycle, and the light intensity can be controlled freely A light emitting diode driving device can be realized.

  In the light emitting diode driving device having this configuration, the reverse recovery time (Trr) of the diode is preferably 100 nsec or less.

  With this configuration, power loss in the switching element can be reduced in a transient state in which the switching element shifts from the off state to the on state.

  The light emitting diode block includes three or more light emitting diode arrays in which a plurality of the light emitting diodes having different emission colors are directly connected to each of the light emitting diode arrays, and the main switching element is provided for each light emitting diode array. And an external terminal for controlling an on period in intermittent on / off control of the current detection circuit and the main switching element by an external signal, and controlling a constant current level flowing through each light emitting diode array, It is preferable that the chromaticity of the light emitting diode block can be controlled.

  With this configuration, if red, green and blue light emitting diodes are arranged for each light emitting diode array, the constant current level flowing for each red, blue and green light emitting diode array can be adjusted, and the light intensity for each color can be controlled. A light-emitting diode driving device having a complicated light control function and high power conversion efficiency can be realized.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a light emitting diode driving device using a semiconductor device 6A for driving a light emitting diode according to Embodiment 1 of the present invention. In the present embodiment, a case will be described in which a light emitting diode block 5 configured by connecting two LED arrays 5A and 5B in which a plurality of light emitting diodes are connected in series to each other in parallel is caused to emit light. The semiconductor device 6A includes a switching element block 7A and a control circuit block 8A.

  One end of the choke coil 3 and the cathode terminals of the diodes 4A and 4B are connected to the high potential side of the full-wave rectifier circuit 2 connected to the AC power source 1. The other end of the choke coil 3 is connected to the anode terminal side of the LED arrays 5A and 5B of the light emitting diode block 5. The anode terminal of the diode 4A and the high potential side terminal VD1 of the switching element block 7A are connected to the cathode terminal of the LED array 5A. The anode terminal of the diode 4B and the high potential side terminal VD2 of the switching element block 7A are connected to the cathode terminal side of the LED array 5B.

  The switching element block 7A includes a junction FET 9 and two switching elements 10A and 10B. The junction type FET 9 and the switching element 10A are connected in series, and the high potential side of the junction type FET 9 is connected to the high potential side terminal VD1. The low potential side output terminal of the switching element 10A and the ground terminal of the control circuit block 8A are connected to the low potential side terminal. The input terminal VJ of the control circuit block 8A is connected to the connection point between the junction FET 9 and the switching element 10A, and the output terminal GATE1 of the control circuit block 8A is connected to the control terminal of the switching element 10A. The high potential side terminal VD2 is connected to the high potential side output terminal of the switching element 10B. The low potential side output terminal of the switching element 10B is connected to the low potential terminal. The output terminal GATE2 of the control circuit block 8A is connected to the control terminal of the switching element 10B.

  The control circuit block 8A has a rectified voltage terminal IN, an input terminal VJ, output terminals GATE1 and GATE2, a ground terminal GND, and a reference voltage terminal Vcc. The rectified voltage terminal IN is connected to the high potential side of the full-wave rectifier circuit 2 and the input voltage detection circuit 21. A capacitor 24 is connected to the reference voltage terminal Vcc. One end of the regulator 11 is connected to the input terminal VJ, and the other end of the regulator 11 is connected to the reference voltage terminal Vcc.

  The output terminal GATE1 is connected to the control terminal of the corresponding switching element 10A, the output terminal GATE2 is connected to the control terminal of the corresponding switching element 10B, and is connected to a drive circuit having the following configuration.

  The high potential side output terminals of the switching elements 10A and 10B are connected to the detection terminals of the drain current detection circuits 18A and 18B having the common detection reference voltage Vsn.

  An output terminal of the AND circuit 13A and an input terminal of the on-time blanking pulse generator 14 are connected to the output terminal GATE1. The input terminal of the AND circuit 13A is connected to the output terminal of the start / stop circuit 12, the MAX DUTY signal output terminal of the oscillator 19, and the output terminal Q of the RS flip-flop circuit 15A. The output terminal of the drain current detection circuit 18A and the output terminal of the on-time blanking pulse generator 14 are connected to the input terminal of the AND circuit 17A. The output of the AND circuit 17A and the inverted signal of the MAX DUTY signal of the oscillator 19 are input to the input of the OR circuit 16A, and the output signal of the OR circuit 16A is input to the reset signal terminal R of the RS flip-flop circuit 15A. .

  The output terminal GATE2 is connected to the output terminal of the AND circuit 13B. The output signal of the start / stop circuit 12, the MAX DUTY signal output terminal of the oscillator 19, and the output terminal Q of the RS flip-flop circuit 15B are connected to the input terminal of the AND circuit 13B. The output terminal of the drain current detection circuit 18B and the output terminal of the on-time blanking pulse generator 14 are connected to the input terminal of the AND circuit 17B. The output of the AND circuit 17B and the inverted signal of the MAX DUTY signal of the oscillator 19 are input to the input of the OR circuit 16B, and the output signal of the OR circuit 16B is input to the reset signal terminal R of the RS flip-flop circuit 15B. The

  The input voltage detection circuit 21 includes a comparator 20 to which the detection reference voltage Vst is input to the − terminal, and two resistors 22 and 23 connected in series. The series connection resistors 22 and 23 have a high potential side connected to the rectified voltage terminal IN of the control circuit block 8A, a low potential side connected to the ground terminal GND / SOURCE of the control circuit block 8A, and an intermediate terminal connected to the + terminal of the comparator 20. It is connected. The output terminal of the comparator 20 is connected to the input terminal of the start / stop circuit 12.

  Next, with reference to FIG. 2 and FIG. 3, the operation of the light emitting diode driving apparatus having the above-described configuration will be described. 2A shows the Vin terminal voltage waveform in the light emitting diode driving device, FIG. 2B shows the waveform of the constant current IL0 flowing through the LED arrays 5A and 5B, and FIG. 2C shows the reference voltage terminal Vcc of the control circuit block 8A. The voltage Vcc is shown.

  The voltage Vin output from the full-wave rectifier circuit 2 has a waveform obtained by full-wave rectifying an AC voltage as shown in FIG. The full-wave rectified voltage Vin is applied to the high potential side of the junction FET 9 of the switching element block 7A via the choke coil 3 and the LED array 5A, and gradually rises as indicated by VD in FIG. As shown in FIG. 3, the high potential side voltage VD1 and the low potential side voltage VJ of the junction FET 9 rise as the VD rises (region A). However, due to pinch-off, when VD ≧ VDP or more, VJ = VJP (region B).

  The voltage Vcc at the reference voltage terminal Vcc of the control circuit block 8A is also increased by the regulator 11 connected to the low potential side of the junction FET 9. When the high-potential side voltage VD becomes VDSTART and the low-potential side voltage VJ reaches the starting voltage Vcc0, the voltage Vcc is controlled by the regulator so as to always become the constant voltage Vcc0, as shown in FIG. The output of the oscillator 19 of the control circuit block 8A is started. When the voltage at the reference voltage terminal Vcc falls below Vcc0, the output of the oscillator 19 is stopped.

  Further, the full-wave rectified voltage Vin is applied to the high potential side of the resistor 22 in the input voltage detection circuit 21 through the rectified power supply terminal IN, and the voltage Vin ′ divided by the resistors 22 and 23 is applied to the + terminal of the comparator 20. Applied. The reference voltage Vst is applied to the negative terminal of the comparator 20, and when the voltage Vin ′ divided by the resistors 22 and 23 reaches the reference voltage Vst, the comparator 20 sends a start signal to the start / stop circuit 12.

  As shown in FIG. 2A, the Vin voltage (Vin1) when the voltage Vin ′ divided by the resistors 22 and 23 reaches the reference voltage Vst is the Vin voltage (Vin2) when the VJ voltage reaches the Vcc0 voltage. ) Is set to be higher. Therefore, intermittent ON / OFF control of the switching elements 10A and 10B by the control circuit block 8A is started when the voltage Vin 'reaches the reference voltage Vst. When the voltage Vin 'divided by the resistors 22 and 23 falls below the reference voltage Vst, the comparator 20 sends a stop signal to the start / stop circuit 12, and the control circuit block 8A keeps the switching elements 10A and 10B in the OFF state.

  As described above, the intermittent on / off control of the switching elements 10A and 10B is executed during the period T1 in which the voltage Vin 'is equal to or higher than the reference voltage Vst, and the constant current IL0 flows through the LED arrays 5A and 5B. During the period T <b> 2 when the voltage Vin ′ is equal to or lower than the reference voltage Vst, the switching elements 10 </ b> A and 10 </ b> B are kept off and no current flows through the light emitting diode 5.

  Next, with reference to FIG. 4, the constant current output operation in the light emitting diode driving device of the present embodiment will be described. 4A shows the voltage at the high potential side terminal VD1, FIG. 4B shows the voltage at the high potential side terminal VD2, FIG. 4C shows the current flowing through the switching elements 10A and 10B, and FIG. 4D flows through the LED arrays 5A and 5B. Indicates current.

  First, the current IL flowing through the LED array 5A will be described. When the on / off control of the switching element 10A by the control circuit block 8A is started by the start / stop circuit 12, the oscillation frequency and the MAX on-duty of the switching element 10A are the CLOCK signal of the oscillator 19 and the MAX DUTY, respectively. Defined by signal. On the other hand, the current flowing through the switching element 10A is detected by comparing the ON voltage of the switching element 10A with the detection reference voltage Vsn of the drain current detection circuit 18A. When the ON voltage of the switching element 10A reaches Vsn, the switching element 10A is turned off until the next CLOCK signal from the oscillator 19 enters the input S of the RS flip-flop 15A. That is, the on-duty of the switching element 10A is defined by the output signal of the OR circuit 16A to which the inverted signal of the MAX DUTY signal of the oscillator 19 and the output signal of the drain current detection circuit 18A are input. An ON-time blanking pulse generator 14 is connected to the control terminal of the switching element 10A, and the output signal of the ON-time blanking pulse generator 14 and the output signal of the drain current detection circuit 18A are input to the AND circuit 17A. Thus, malfunction of on / off control of the switching element 10A due to ringing that occurs when the switching element 10A changes from the off state to the on state is prevented.

  As described above, the on / off control of the switching element 10A is performed by the control circuit block 8A, and the current ID flowing through the switching element 10A has a waveform as shown in FIG. When the switching element 10A is in the on state, the current ID having a peak at IDP flows in the direction of the choke coil 3 → the LED array 5A → the switching element 10A. When the switching element 10A is in the off state, the choke coil 3 → The LED array 5A flows through a closed loop of the diode 4A. Therefore, the current IL flowing through the LED array 5A has a waveform as shown in FIG. 4D, and the average current flowing through the LED array 5A is IL0 shown in FIG. 4D.

  Next, the current IL ′ flowing through the LED array 5B will be described. When the on / off control of the switching element 10B by the control circuit block 8A is started by the start / stop circuit 12, the oscillation frequency and the MAX on-duty of the switching element 10B are respectively set to the oscillator 19 similarly to the switching element 10A. CLOCK signal and MAX DUTY signal. On the other hand, the current flowing through the switching element 10B is detected by comparing the ON voltage of the switching element 10B with the detection reference voltage Vsn of the drain current detection circuit 18B. When the ON voltage of the switching element 10B reaches Vsn, the switching element 10B is turned off until the next CLOCK signal from the oscillator 19 enters the input S of the RS flip-flop 15B. That is, the on-duty of the switching element 10B is defined by the output signal of the OR circuit 16B to which the inverted signal of the MAX DUTY signal of the oscillator 19 and the output signal of the drain current detection circuit 18B are input. At this time, since the drain current detection circuits 10A and 10B operate with the same detection reference voltage Vsn, the drain peak current value flowing through the switching element 10A and the drain peak current value flowing through the switching element 10B become the same value.

  As described above, the ON / OFF control of the switching element 10B is performed by the control circuit block 8A, and the current ID 'flowing through the switching element 10B has a waveform as shown in FIG. The current ID ′ having a peak at IDP flows in the direction of the choke coil 3 → the LED array 5B → the switching element 10B when the switching element 10B is in the on state, and when the switching element 10B is in the off state, the choke coil 3 → LED array 5B → Diode 4B flows in a closed loop.

  Due to the difference in forward voltage between the LED arrays 5A and 5B, the time until the drain current of each switching element 10A and 10B reaches the peak current, that is, the ON period of each switching element, is shown in FIGS. As shown in FIG. However, since the drain peak current flowing through each of the switching elements 10A and 10B and the timing of the next ON state are the same, the average current IL0 flowing through each LED array is substantially the same.

  When the light emitting diode driving device using the semiconductor device of the present embodiment is used, the following effects are obtained.

  First, there is no power loss when starting up the light emitting diode driving device. In general, power is supplied to a semiconductor device from an input voltage (high voltage) through a resistor in a direct current, and this power supply is performed not only during start / stop but also during normal operation. A power loss occurs in the resistor. However, according to the present embodiment, such a resistor is not necessary.

  Next, the constant current flowing through the switching elements 10A and 10B is determined by detecting the ON voltages of the switching elements 10A and 10B by the drain current detection circuits 18A and 18B, respectively. There is no need for connection, and no power loss is caused by circuit elements connected in series with the light emitting diode.

  Further, by using the junction FET 9, it is possible to realize a light emitting diode driving device that can obtain a small and stable light emission luminance with a small number of components from a low voltage to a high voltage as an input power source.

  In general, a white light-emitting diode is composed of a blue light-emitting diode that emits blue light by a drive current and a YAG-based phosphor that converts blue to yellow, and the phosphor is fluorescent by blue light from the blue light-emitting diode. White light is emitted by emitting light. It is known that such a white light emitting diode has a correlation with respect to its forward current value and chromaticity and luminous intensity. That is, when the forward current value increases, not only the relative luminous intensity increases, but also the chromaticity changes. Therefore, in order to adjust the luminous intensity while keeping the chromaticity constant, it is necessary to make the forward current value of the light emitting diode constant and to adjust the current flowing period during the certain period.

  When the light emitting diode is driven by the driving device using the semiconductor device of the present embodiment, the forward current value of the light emitting diode can be easily adjusted by changing the detection reference voltage Vsn of the drain current detection circuits 18A and 18B. Furthermore, the start / stop voltage can be easily adjusted by changing the reference voltage Vst. Therefore, when a commercial power source is used as the AC power source 1, the light emitting diode that can easily adjust the chromaticity and the luminous intensity of the white light emitting diode can be easily adjusted in the period of light emission and the period of extinction during the double period (100 Hz / 120 Hz) A drive device can be realized.

  In the circuit of FIG. 1, the semiconductor device 6A has a configuration in which the switching element block 7A and the control circuit block 8A are formed on the same substrate, whereby the light emitting diode driving device can be downsized. The same applies to the embodiments described below.

  Further, in the configuration of FIG. 1, by using a diode whose reverse recovery time of the diodes 4A and 4B is 100 ns or less, the switching element 10A and 10B in the transient state in which the switching state is changed from the off state to the on state. It is possible to reduce the power loss to a practically sufficient level.

  In the configuration of FIG. 1, the full-wave rectifier circuit 2 is used as means for rectifying the AC voltage. However, it is obvious that the same effect can be obtained even if a half-wave rectifier circuit is used. The same applies to the embodiments described below.

  Further, although not shown in FIG. 1, a clamp circuit such as a Zener diode connected in parallel may be connected to the high potential side and the low potential side of the switching element block 7A.

  In the intermittent on / off control of the switching elements 10A and 10B by the control circuit block 8A, when the switching elements 10A and 10B shift from the on state to the off state, the high-voltage side terminal voltage of the switching element block 7A becomes the wiring capacitance or Ringing caused by the wiring inductance may result in a voltage exceeding the withstand voltage of the switching elements 10A and 10B, which may lead to destruction of the switching elements 10A and 10B.

  In such a case, by connecting a clamp circuit having a clamp voltage lower than the breakdown voltage of the switching elements 10A and 10B, the high-voltage side terminal voltage VD of the switching element block 7A is clamped by this clamp voltage, and the switching element 10A , 10B can be prevented, and a highly safe light emitting diode driving device can be realized.

  Also in the following embodiments, the same effect can be obtained by adding a clamp circuit.

(Embodiment 2)
FIG. 5 shows a light emitting diode driving device using the semiconductor device 6B for driving a light emitting diode in the second embodiment of the present invention. This light emitting diode driving device is shown in FIG. 1 except that the connection of the junction type FET 9 of the switching element block 7B is different, and the drain current detection method and configuration by the drain current detection circuits 18A and 18B in the control circuit block 8B are different. The configuration is the same as that of the circuit of the first embodiment.

  A configuration in which a switching element 25A in which a current having a constant current ratio is smaller than a current flowing in the switching element 10A is connected in parallel to the switching element 10A, and a resistor 26A is connected in series to a low potential side terminal of the switching element 25A And The current flowing through the switching element 25A is detected by the voltage across the resistor 26A and used as the input of the drain current detection circuit 18A. The detection method of the drain current detection circuit 18B is the same.

  With the configuration as described above, since a large current is not directly detected by the resistor, it is possible to detect the current of the switching element with reduced power loss.

(Embodiment 3)
FIG. 6 shows a light emitting diode driving device using the light emitting diode driving semiconductor device 6C according to the third embodiment of the present invention. This light emitting diode driving apparatus has the same configuration as the circuit of the second embodiment shown in FIG. 5 except that an overheat protection circuit 38 is added to the input terminals of the AND circuits 13A and 13B in the control circuit block 8C.

  By adding the overheat protection circuit 38, the temperatures of the switching elements 10A and 10B are detected. In particular, when the switching element block 7B and the control circuit block 8C are configured by a semiconductor device formed on the same substrate, the temperature detection accuracy is increased. When an abnormal temperature rise of the switching elements 10A and 10B is detected by the overheat protection circuit 38, a signal for forcibly turning off the switching elements 10A and 10B is output from the overheat protection circuit 38 to the inputs of the AND circuits 13A and 13B. The temperature of the switching elements 10A and 10B is lowered.

  Here, the forcible OFF state release operation of the switching elements 10A and 10B includes a latch mode in which the power supply to the light emitting diode driving device is temporarily stopped, and this OFF state is maintained until it is restarted, and the overheat protection circuit 38. The switching elements 10A and 10B are held in the off state until the temperature becomes equal to or lower than the temperature specified by the above, and the self-recovery mode in which the off state is automatically canceled when the temperature becomes lower than the specified temperature can be adopted. .

  When the light emitting diode driving device of the present embodiment is used, in addition to the effects shown in the first and second embodiments, the destruction of the switching elements 10A and 10B due to an abnormal temperature rise can be avoided. A light emitting diode driving device with high height can be realized.

  Also in the following embodiments, the same effect can be obtained by adding the overheat protection circuit 38.

(Embodiment 4)
FIG. 7 shows a light-emitting diode driving device using a semiconductor device 6D for driving a light-emitting diode according to Embodiment 4 of the present invention. This light emitting diode driving device is different in the connection of the junction type FET 9 of the switching element block 7C, except that the terminal SN that determines the detection reference voltage Vsn of the drain current detection circuits 18A and 18B of the control circuit block 8D is an external terminal. The configuration is the same as that of the circuit of the second embodiment shown in FIG.

  With reference to FIG. 8, the operation when the current IL flowing through the LED array 5A changes will be described. The start / stop operation of the light emitting diode driving apparatus of the present embodiment is basically the same as that of the light emitting diode driving apparatus of the first embodiment.

  The detection reference voltage Vsn of the drain current detection circuits 18A and 18B is variable depending on the voltage input to the external terminal SN. Here, for example, as shown in FIG. 8 (e), when the SN terminal voltage Vsn is gradually reduced in three stages, the drain current detection level is also gradually lowered in three stages. Gradually decreases in three stages. As a result, the PWM-controlled current ID flows through the switching element 10A as shown in FIG. 8C, the current IL as shown in FIG. 8D flows through the LED array 5A, and the LED array 5A. The average current ILO is as shown in FIG. That is, the average current of the LED array 5A changes depending on the Vsn voltage.

  The operation of the drain current detection circuit 18A has been described on the assumption that the average current of the light emitting diode 5A changes in proportion to the change in the detection reference voltage Vsn. Then, the LED array 5A may be operated so that the average current changes in inverse proportion.

  When the light emitting diode driving device of the present embodiment is used, the following effects are obtained in addition to the effects shown in the third embodiment.

  By providing the terminal for determining the detection reference voltage of the drain current detection circuit as the external terminal SN, the forward current value of the light emitting diode can be easily adjusted from the outside. That is, the chromaticity of the white light emitting diode can be adjusted.

  Also in the following embodiments, it is possible to obtain the same effect by applying the same configuration as the present embodiment.

(Embodiment 5)
FIG. 9 shows a light-emitting diode driving device using the semiconductor device 6E for driving a light-emitting diode in the fifth embodiment of the present invention. This light emitting diode driving device is the same as that of the fourth embodiment shown in FIG. 7 except that terminals SN1 and SN2 for determining the detection reference voltages of the drain current detection circuits 18A and 18B in the control circuit block 8E are external terminals. The configuration is the same as that of the circuit.

  When the light emitting diode driving device of the present embodiment is used, the following effects can be obtained in addition to the effects shown in the third embodiment.

  By providing the terminals that determine the detection reference voltages of the drain current detection circuits 18A and 18B as the external terminals SN1 and SN2, the forward current values of the LED arrays 5A and 5B can be easily adjusted individually from the outside. That is, the chromaticity of the white light emitting diode can be adjusted.

  In the circuit of FIG. 9, an example in which two LED arrays are connected in parallel is shown. However, a light emitting diode array is provided with three or more rows of light emitting diode arrays, and red, green, and blue light emitting diodes are arranged for each light emitting diode array. It is also possible to employ a configuration including an external terminal that can control the switching element, the current detection circuit, and the on period in the intermittent on / off control of the switching element by an external signal. As a result, the constant current level flowing through each LED array can be controlled individually, so that the chromaticity can be freely set as the LED light source.

(Embodiment 6)
FIG. 10 shows a light emitting diode driving device using the semiconductor device 6F for driving a light emitting diode according to the sixth embodiment of the present invention. In this light emitting diode driving device, the configuration of the control circuit block 8F differs from the configuration of the fourth embodiment shown in FIG. 7 as follows.

  That is, the oscillator 35 supplies a sawtooth wave SAWTOOTH signal in addition to the MAX DUTY signal and the CLOCK signal. The SAWTOOTH signal and the voltage signal Vsn at the external terminal SN are compared by the comparator 34. Then, instead of the inverted signal of the MAX DUTY signal, the output signal of the comparator 34 is input to the OR circuits 37A and 37B corresponding to the OR circuits 16A and 16B in FIG. As another input of the OR circuits 37A and 37B, outputs of the AND circuits 36A and 36B corresponding to the AND circuits 17A and 17B in FIG. 7 are input.

  The drive control of the switching element 10A by the control circuit block 8F will be described. In the drain current detection circuit 18A, the current flowing through the switching element 25A is detected by the voltage across the resistor 26A, but the detection reference voltage is constant, and therefore the maximum value of the current flowing through the switching element 10A is always constant.

  An output signal obtained by comparing the SAWTOOTH signal with the voltage signal Vsn of the external terminal SN by the comparator 34 and an output signal of the OR circuit 37A to which the output signal of the AND circuit 36A is input are supplied to the reset signal terminal R of the RS flip-flop circuit 15A. Entered. Therefore, if the input voltage to the external terminal SN is changed, the on-duty of the switching element 10A changes and PWM control is performed. The same applies to the control of the switching element 10B.

  When the light emitting diode driving apparatus according to the present embodiment is used, there is a difference in the configuration as described above, but the current / voltage waveforms at the respective terminals are the same as those in FIG. 8, and the configuration of the fourth embodiment shown in FIG. The same effect can be obtained.

(Embodiment 7)
FIG. 11 shows a light emitting diode driving device using the semiconductor device 6G for driving a light emitting diode in the seventh embodiment of the present invention. This light emitting diode driving device differs from the configuration of the fourth embodiment shown in FIG. 7 in the configuration relating to the input voltage detection circuit 21 of the control circuit block 8G as follows.

  That is, the terminal that determines the detection reference voltage Vst of the input voltage detection circuit 21 is configured as the external terminal ST.

  Since the detection reference voltage Vst of the input voltage detection circuit 21 can be varied according to the voltage input to the external terminal ST, the start / stop voltage can be easily adjusted. Therefore, when a commercial power source is used as the AC power source 1, the period of light emission and the period of quenching can be easily adjusted during the double period (100 Hz / 120 Hz), and the chromaticity and luminous intensity of the white light emitting diode can be easily adjusted.

(Embodiment 8)
FIG. 12 shows a light-emitting diode driving device using the semiconductor device 6H for driving a light-emitting diode in the eighth embodiment of the present invention. This light-emitting diode driving device is different from the seventh embodiment shown in FIG. 11 in the configuration relating to the input voltage detection circuit 21 of the control circuit block 8H as follows.

  The input voltage detection circuit 21 includes two resistors 22 and 23 connected in series between a rectified power supply terminal IN to which a voltage that has been full-wave rectified by the full-wave rectifier circuit 2 is input and a ground terminal of the control circuit block 8H. The DC voltage vin ′ divided by the resistance division is input to one input terminal of each of the first and second comparators 28 and 29, and the other input terminal of the first and second comparators 28 and 29, respectively. It is composed of two external terminals (LOW level input terminal, HI level input terminal) to be connected, and a NOR circuit 27 to which the output terminals of the first and second comparators 28 and 29 are connected.

  The LOW level input terminal INL is connected to the + terminal of the first comparator 28, and the DC voltage Vin 'is input to the-terminal. The HI level input terminal INH is connected to the negative terminal of the second comparator 29, and the DC voltage Vin 'is input to the positive terminal. Output signals of the first and second comparators 28 and 29 are input to the start / stop circuit 12 through the NOR circuit 27. Voltages (VH, VL) divided by three series-connected resistors 30, 31, 32 are input to the input terminals INH, INL, respectively, and there is a relationship of VH> VL.

  The operation of the light-emitting diode driving apparatus according to the present embodiment will be described with reference to FIGS.

  When Vin ′ divided by the two resistors 22 and 23 reaches VL, the input voltage detection circuit 21 sends a start signal to the start / stop circuit 12, and the control circuit block 8H intermittently switches the switching elements 10A and 10B. On / off control is started. When Vin 'reaches VH, the input voltage detection circuit 21 sends a stop signal to the start / stop circuit 12, and the control circuit block 8H keeps the switching elements 10A and 10B in the OFF state.

  That is, as shown in FIG. 13, the switching elements 10A and 10B perform intermittent on / off control during a period in which the Vin ′ voltage is VL or more and VH or less, and the light emitting diode emits light. During a period in which the Vin ′ voltage is not less than VH and not more than VL, the switching elements 10A and 10B are kept off, and the light emitting diode is extinguished.

  Here, the voltages VH and VL are determined by being divided by three series-connected resistors 30, 31, and 32. However, the present invention is not limited to this. Any signal that has a relationship of VH> VL and that can achieve a relationship in which Vin ′ changes from a voltage lower than VL to a voltage higher than VH with respect to a change in the full-wave rectified voltage Vin may be used.

  With the configuration as described above, since the level of the start voltage and the stop voltage in one cycle can be set individually, it is possible to realize a light emitting diode driving device with high power conversion efficiency capable of more complex light intensity adjustment.

(Embodiment 9)
FIG. 14 shows a light emitting diode driving device using the semiconductor device 6I for driving a light emitting diode according to the ninth embodiment of the present invention. In this light emitting diode driving device, except that the high potential side of the series connection resistors 22 and 23 of the input voltage detection circuit 21 in the control circuit block 8I is connected to the low potential side of the junction FET 9 of the switching element block 7C. The configuration is the same as that of the fourth embodiment shown in FIG.

  In this way, the power loss generated in the resistors 22 and 23 can be reduced by dividing the full-wave rectified voltage Vin directly by resistance and by dividing the low potential side voltage VJ of the junction FET 9 by resistance.

(Embodiment 10)
FIG. 15 shows a light-emitting diode driving device using the semiconductor device 6J for driving the light-emitting diode according to the tenth embodiment of the present invention. This light-emitting diode driving device is configured such that the high potential side of the series connection resistors 22 and 23 of the input voltage detection circuit 21 in the control circuit block 8J is connected to the low potential side of the junction FET 9 of the switching element block 7C. The configuration is the same as that of the seventh embodiment shown in FIG. 11, and the obtained effect is the same as that of the ninth embodiment.

(Embodiment 11)
FIG. 16 shows a light emitting diode driving device using the semiconductor device 6K for driving a light emitting diode in the eleventh embodiment of the present invention. This light-emitting diode driving device is configured in such a manner that the high potential side of the series connection resistors 22 and 23 of the input voltage detection circuit 21 in the control circuit block 8K is connected to the low potential side of the junction FET 9 of the switching element block 7C. The configuration is the same as that of the eighth embodiment shown in FIG. 12, and the obtained effect is the same as that of the ninth embodiment.

  In the configuration shown in FIGS. 12 and 16, the levels of the start voltage and stop voltage of the switching elements 10A and 10B are the same. However, the input voltage detection circuit and the start / stop circuit are provided for each of the switching elements 10A and 10B. As a configuration provided, the switching elements 10A and 10B may be controlled to start / stop at arbitrary voltages VH and VL.

(Embodiment 12)
FIG. 17 shows a light-emitting diode driving device using the semiconductor device 6L for driving the light-emitting diode according to the twelfth embodiment of the present invention. This light emitting diode driving device is the same as that of the eleventh embodiment shown in FIG. 16 except that the soft start circuit 33 is provided between the external detection terminal SN and the drain current detection circuit 18 in the control circuit block 8L. It is a configuration.

  The soft start circuit 33 is also connected to the start / stop circuit 12. When the activation signal is input, the soft start circuit 33 outputs the detection reference voltage Vsn so as to gradually increase until reaching a certain value.

  By adopting such a configuration, it is possible to prevent an inrush current that occurs at the time of start-up, and it is possible to gradually increase the forward current flowing through the light-emitting diode and gradually increase the light intensity of the light-emitting diode.

  The present invention can be used for all apparatuses and devices using light emitting diodes, and is particularly useful as an LED lighting device.

1 is a circuit diagram of a light-emitting diode driving apparatus according to Embodiment 1 of the present invention. Waveform diagram showing the operation of the LED driving device of FIG. Waveform diagram for explaining the operation of the junction type FET in the light emitting diode driving device of FIG. Waveform diagram showing the constant current output operation of the LED driving device of FIG. Circuit diagram of light-emitting diode driving apparatus according to Embodiment 2 of the present invention Circuit diagram of light-emitting diode driving apparatus according to Embodiment 3 of the present invention Circuit diagram of a light-emitting diode driving apparatus according to Embodiment 4 of the present invention Waveform diagram showing the constant current output operation of the light emitting diode driving device of FIG. Circuit diagram of light-emitting diode driving apparatus according to Embodiment 5 of the present invention Circuit diagram of light-emitting diode driving apparatus according to Embodiment 6 of the present invention Circuit diagram of light-emitting diode driving apparatus according to Embodiment 7 of the present invention Circuit diagram of light-emitting diode driving apparatus according to Embodiment 8 of the present invention FIG. 12 is a waveform diagram showing the operation of the light emitting diode driving apparatus of FIG. Circuit diagram of a light emitting diode driving apparatus according to Embodiment 9 of the present invention Circuit diagram of a light-emitting diode driving apparatus according to Embodiment 10 of the present invention Circuit diagram of light-emitting diode driving apparatus according to Embodiment 11 of the present invention Circuit diagram of a light-emitting diode driving apparatus according to Embodiment 12 of the present invention The circuit diagram which shows schematic structure of the light emitting diode drive device of a prior art example The circuit diagram which shows schematic structure of the light emitting diode drive device of another prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,204 AC power supply 2,205 Rectifier circuit 3 Choke coil 4A, 4B Diode 5 Light emitting diode block 5A, 5B LED array 6A-6L Semiconductor device 7A-C Switching element block 8A-8L Control circuit block 9 Junction type FET
10A, 10B switching element 11 regulator 12 start / stop circuit 13A, 13B AND circuit 14 ON-time blanking pulse generator 15A, 15B RS flip-flop circuit 16A, 16B, 37A, 37B OR circuit 17A, 17B, 36A, 36B AND circuit 18A, 18B Drain current detection circuit 19, 35 Oscillator 20, 28, 29, 34 Comparator 21 Input voltage detection circuit 22, 23, 26A, 26B, 30, 31, 32 Resistor 24 Capacitor 25A, 25B N-type MOSFET
27 NOR circuit 33 Soft start circuit 100, 201 LED array circuit 101 Current limiting resistor 102, 103 Light emitting diode 104, 121, 131 Bipolar transistor 110 Constant voltage circuit 120 Constant current circuit 130 Switching means 140 Dimming circuit 202 LED series circuit 203 Constant Current circuit 206 Constant voltage regulator 207 Control means 208 Comparison means

Claims (21)

A light emitting diode block having a plurality of light emitting diode arrays formed by connecting a plurality of light emitting diodes in series, a choke coil connected in series to the light emitting diode block, and a counter electromotive force generated in the choke coil A plurality of diodes for supplying to a plurality of light emitting diode arrays, a rectifying circuit for rectifying an AC voltage of an AC power source and applying the rectified voltage to the light emitting diode block and the choke coil, and for supplying a current to the light emitting diode block A light emitting diode driving semiconductor device constituting the switching driving circuit in a light emitting diode driving device comprising a switching driving circuit,
A switching element block and a control circuit block;
The switching element block includes a plurality of main switching elements connected in series for each light emitting diode array;
And at least one junction type FET connected corresponding to the main switching element,
The control circuit block is
An input terminal connected to the other end of the junction FET;
A reference voltage terminal connected to the input terminal and outputting a reference voltage;
An input voltage detection circuit for detecting a voltage obtained by rectifying the AC voltage;
When the output voltage of the input voltage detection circuit becomes equal to or higher than a predetermined value, an on operation based on intermittent on / off control at a predetermined oscillation frequency for the plurality of main switching elements is started, and the output voltage of the input voltage detection circuit is A start / stop circuit that stops when less than a predetermined value;
A plurality of current detection circuits for respectively detecting currents flowing through the plurality of main switching elements;
A light emitting diode driving semiconductor device comprising: a control circuit that controls an off operation so that a current flowing through the main switching element is constant according to a detection signal from each of the current detection circuits. The switching element block has a plurality of control terminals, a plurality of high potential side terminals, and a low potential side terminal,
One output terminal of the main switching element paired with the output terminal of the junction FET is connected,
Each output terminal of the control circuit block and each control terminal of the plurality of main switching elements are connected to the control terminals,
An input terminal of the junction type FET is connected to the high potential side terminal, and an input terminal of the control circuit block is connected to a connection portion of the output terminal of the main switching element paired with the output terminal of the junction type FET,
2. The semiconductor device for driving a light emitting diode according to claim 1, wherein the other output terminal of the plurality of main switching elements and the ground terminal of the control circuit block are connected to the low potential side terminal. The switching element block has a plurality of control terminals, a plurality of high potential side terminals, and a low potential side terminal,
Each output terminal of the control circuit block and each control terminal of the plurality of main switching elements are connected to the control terminals,
One output terminal of the plurality of main switching elements is connected to each high potential side terminal,
The input terminal of the junction FET is connected to one of the high potential side terminals, and the input terminal of the control circuit block is connected to the output terminal of the junction FET,
2. The semiconductor device for driving a light emitting diode according to claim 1, wherein the other output terminal of the plurality of main switching elements and the ground terminal of the control circuit block are connected to the low potential terminal. The switching element block has a plurality of control terminals, a rectified voltage source terminal, a plurality of high potential side terminals, and a low potential side terminal,
Each output terminal of the control circuit block and each control terminal of the plurality of main switching elements are connected to the control terminals,
The output terminal of the rectifier circuit and the input terminal of the junction FET are connected to the rectified power supply terminal, and the input terminal of the control circuit block is connected to the output terminal of the junction FET.
One output terminal of the plurality of main switching elements is connected to each high potential side terminal,
2. The semiconductor device for driving a light emitting diode according to claim 1, wherein the other output terminal of the plurality of main switching elements and the ground terminal of the control circuit block are connected to the low potential terminal.   The light emitting diode driving semiconductor device according to claim 1, wherein the control circuit block has a regulator inserted between an input terminal and a reference voltage terminal.   6. The light emitting device according to claim 1, wherein the plurality of current detection circuits detect a current flowing through each of the switching elements by comparing an ON voltage of the plurality of main switching elements with a detection reference voltage. Diode drive semiconductor device. The plurality of current detection circuits include:
A plurality of sub-switching elements each having a pair of a control terminal and a high-potential side terminal connected in parallel to the plurality of main switching elements;
A resistor connected in series on the low potential side of each of the sub-switching elements,
The current flowing through the sub-switching element is set to be smaller than the current flowing through the main switching element and a constant current ratio with respect to the current flowing through the main switching element,
The semiconductor device for driving a light-emitting diode according to claim 1, wherein the current of each main switching element is detected by comparing a voltage between both ends of each resistor with a detection reference voltage.   An on-period in intermittent on-off control of the main switching element by further including an external detection terminal connected to the plurality of current detection circuits, and changing a value of the detection reference voltage input to the external detection terminal The semiconductor device for driving a light emitting diode according to claim 1, wherein the constant current level flowing through the light emitting diode block can be adjusted.   Each of the external detection terminals connected to the plurality of current detection circuits further includes intermittent detection of the main switching element by changing a value of the detection reference voltage input to the plurality of external detection terminals. 8. The light emitting diode driving device according to any one of claims 1 to 7, wherein an on period in on / off control is configured to be changeable by an external signal, and a constant current level flowing through the light emitting diode array can be individually adjusted. Semiconductor device.   The input voltage detection circuit includes two resistors connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block, and resistance division by the two resistors. The semiconductor device for driving a light-emitting diode according to claim 1, further comprising: a comparator in which the divided DC voltage is input to the + terminal, and a preset reference voltage is input to the − terminal. .   The input voltage detection circuit includes two resistors connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block, and resistance division by the two resistors. Comparing a divided DC voltage to the + terminal and a reference voltage to the-terminal, and adjusting the voltage at which the switching element starts / stops by changing the reference voltage with an external signal The semiconductor device for driving a light-emitting diode according to claim 1, which is possible. The input voltage detection circuit is
Two resistors connected in series between a rectified power supply terminal to which a voltage rectified by the rectifier circuit is input and a ground terminal of the control circuit block;
First and second comparators, each of which receives a DC voltage divided by resistance division by the two resistors and is input to one input terminal;
An HI level input terminal and a LOW level input terminal which are external terminals respectively connected to the other input terminals of the first and second comparators;
A NOR circuit to which output terminals of the first and second comparators are connected,
In the first comparator, the LOW level input terminal is connected to the + terminal, and the DC voltage divided by the resistance division is input to the − terminal to define the lower limit of the start level of the start / stop circuit. Outputs the comparison result for the input voltage VL,
In the second comparator, the HI level input terminal is connected to a negative terminal, and a DC voltage divided by the resistance division is input to a positive terminal to define an upper limit of the starting level of the starting / stopping circuit. Outputs the comparison result for the input voltage VH,
11. The semiconductor device for driving a light emitting diode according to claim 1, wherein start / stop can be controlled by arbitrary voltages VH and VL. The low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block,
5. The LED driving circuit according to claim 4, wherein the input voltage detection circuit includes a comparator in which a low-potential side output terminal of the junction FET is connected to a + terminal and a preset reference voltage is input to a − terminal. Semiconductor device. The low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block,
The input voltage detection circuit is configured by a comparator in which a low-potential side output terminal of the junction FET is connected to a + terminal and a reference voltage is input to a − terminal.
5. The semiconductor device for driving a light emitting diode according to claim 4, wherein a voltage at which the switching element is started / stopped can be adjusted by changing the reference voltage by an external signal. The low potential side output terminal of the junction FET is connected to the input terminal of the control circuit block,
The input voltage detection circuit is
First and second comparators in which the low potential side output terminal of the junction FET is connected to one input terminal;
An HI level input terminal and a LOW level input terminal which are external terminals respectively connected to the other input terminals of the first and second comparators;
A NOR circuit to which output terminals of the first and second comparators are connected,
The first comparator has a + terminal connected to the LOW level input terminal and a − terminal connected to the low potential side output terminal of the junction FET to define a lower limit of the start level of the start / stop circuit. Outputs the comparison result for the input voltage VL,
The second comparator has an HI level input terminal connected to a negative terminal and a low potential side output terminal of the junction FET connected to a positive terminal to define an upper limit of the startup level of the start / stop circuit. Outputs the comparison result for the input voltage VH,
5. The semiconductor device for driving a light emitting diode according to claim 4, wherein start / stop can be controlled by arbitrary voltages VH and VL.   16. The light emitting diode according to claim 12 or 15, comprising the input voltage detection circuit and the start / stop circuit corresponding to each of the light emitting diode arrays, wherein the start / stop can be controlled with arbitrary voltages VH and VL. Driving semiconductor device.   A soft start circuit is provided between the external detection terminal and the current detection circuit, and when the start signal is input from the start / stop circuit, the soft start circuit gradually increases the detection reference voltage until reaching a certain value. The semiconductor device for driving a light-emitting diode according to claim 1, wherein the output is performed as described above.   The semiconductor device for driving a light-emitting diode according to claim 1, further comprising an overheat protection circuit. A light-emitting diode block including a plurality of light-emitting diode arrays formed by connecting a plurality of light-emitting diodes in series;
A choke coil connected in series to the light emitting diode block;
A plurality of diodes for supplying back electromotive force generated in the choke coil to the plurality of light emitting diode arrays;
A rectifying circuit for rectifying an AC voltage of an AC power source and applying the rectified voltage to the light emitting diode block and the choke coil;
A switching drive circuit for supplying current to the light emitting diode block;
The light emitting diode drive device characterized by the said switching drive circuit being comprised by the semiconductor device for a light emitting diode drive of any one of Claims 1-18.   The light emitting diode driving device according to claim 19, wherein a reverse recovery time (Trr) of the diode is 100 nsec or less. The light emitting diode block includes the light emitting diode array of three or more rows in which a plurality of the light emitting diodes having different emission colors are directly connected for each light emitting diode array,
Each light emitting diode array includes an external terminal for controlling an on period in an intermittent on / off control of the main switching element, the current detection circuit, and the main switching element by an external signal, and each light emitting diode array includes The light emitting diode driving device according to claim 19, wherein the chromaticity of the light emitting diode block can be controlled by respectively controlling a flowing constant current level.

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