JP3275214B2 - Discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device for lighting, for example, a discharge lamp, and more particularly to a discharge lamp lighting device capable of outputting a high-frequency voltage having a high input power factor and low power supply harmonics.

[0002]

2. Description of the Related Art FIG. 17 is a circuit diagram of a conventional discharge lamp lighting device, and FIG. 18 is a waveform diagram of an input voltage and an input current of the discharge lamp lighting device. In the figure, 1 is an AC power supply, 2 is a rectifier circuit composed of a diode bridge or the like for rectifying the AC power supply 1, and 3 is a smoothing capacitor 3 connected between output terminals of the rectifier circuit 2. The switching elements 4 and 5 connected in series to each other are connected in parallel to the smoothing capacitor 3. In order to supply a regenerative current to these switching elements 4 and 5, diodes 6 and 7 are equivalently and anti-parallel to each other.
Is connected. A switch control circuit 8 drives the switching elements 4 and 5 alternately at a high frequency. A coupling capacitor 9, a current limiting inductance element 10, and a discharge lamp 12 are connected in series between a connection point of the switching elements 4 and 5 and a ground portion of the rectifier circuit 2. The condenser 11 is connected to the discharge lamp 12 in parallel.

The conventional discharge lamp lighting device is configured as described above. For example, the switching elements 4 and 5 are turned on and off alternately at a certain switching frequency by a switch control circuit 8.
The high-frequency power is turned off from the connection point of the switching elements 4 and 5 via the coupling capacitor 9 and the current-limiting inductance element 10 to the discharge lamp 12 as a load element.
To supply. Then, a series resonance circuit is formed by the capacitor 11, the inductance element 10, and the capacitor 9 connected in parallel to the discharge lamp 12, and a high voltage necessary for discharging is generated from both ends of the capacitor 11, and the discharge lamp 12 is turned on. Let me. Japanese Patent Application Laid-Open No. 58-209896 discloses a technique substantially the same as the above-mentioned conventional example, and Japanese Patent Application Laid-Open No. 3-283297 discloses a circuit using the conventional example as a basic circuit.

[0004]

The conventional discharge lamp lighting device is of the capacitor input type as described above, and the power supply input current has a pulse-like sharp current as shown in FIG. There is a problem that the power factor decreases and the power supply harmonics increase. By the way, there is a method of using a choke input type smoothing circuit to increase the input in the rectifying and smoothing circuit. However, the choke input type requires a large and heavy choke. In addition, there is a new problem that the loss due to the choke is large and is not suitable for increasing the efficiency and reducing the size of the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to increase the input power factor, reduce power supply harmonics, and reduce the size, efficiency and cost. An object is to obtain a discharge lamp lighting device.

[0006]

According to a first aspect of the present invention, there is provided a rectifying circuit for full-wave rectifying an alternating current of an alternating current power supply, a charging capacitor for charging an output of the rectifying circuit via a coil and a separating diode, and a charging capacitor for the charging capacitor. A pair of series-connected switching elements connected in parallel; a switch drive control circuit that outputs a high-frequency drive signal to each of the pair of switching elements; a connection point between the coil and the separation diode; and a negative output terminal of a rectifier circuit. A pair of series-connected coupling capacitors, a discharge lighting load circuit provided between a connection point of the pair of switching elements and a connection point of the pair of coupling capacitors, and the pair of coupling capacitors. One of the coupling capacitors is connected in parallel via an isolation diode and the other is a pair of series-connected diodes connected directly in parallel. The switch drive control circuit has a drive signal whose frequency is changed in accordance with the increase or decrease of the output voltage of the rectifier circuit in each half cycle of the AC power supply, or an amplitude within each half cycle of the AC power supply. It outputs at least one of the drive signals whose width is changed so as to contradict the increase or decrease of the output voltage of the rectifier circuit.

[0007]

[0008]

According to a second aspect of the present invention, there is provided a rectifier circuit for full-wave rectifying an alternating current of an AC power supply, a pair of series-connected coupling capacitors connected in parallel to the positive and negative output terminals of the rectifier circuit, and a positive and negative output terminal of the rectifier circuit. A pair of series-connected switching elements connected in parallel via an isolation diode, a switch drive control circuit that outputs a high-frequency drive signal to each of the pair of switching elements, a connection point of the pair of switching elements, and the pair of switching elements. A discharge lighting load circuit provided between the connection point of the coupling capacitor, a coil connected to a connection point of the pair of switching elements via a diode, and a low potential side of the coil and the switching element. A charging capacitor connected between the switching element and a diode connected between the coil and the high potential side of the switching element. Is shall.

According to a third aspect of the present invention, there is provided a rectifier circuit for performing full-wave rectification of alternating current of an AC power supply, a pair of series-connected coupling capacitors connected in parallel to positive and negative output terminals of the rectifier circuit via a coil, and A pair of switching elements connected in series to a coupling capacitor via a separation diode, a switch drive control circuit for outputting a high-frequency drive signal to each of the pair of switching elements, and a connection point of the pair of switching elements And a discharge lighting load circuit provided between the connection point of the pair of coupling capacitors,
A diode connected to a connection point of the pair of switching elements, a charging capacitor connected between the diode and the high potential side of the switching element, and a diode connected between the coil and the low potential side of the switching element. And a diode connected between a positive output terminal of the rectifier circuit and a connection point of the pair of switching elements.

According to a fourth aspect of the present invention, there is provided a rectifier circuit for full-wave rectifying an alternating current of an AC power supply, a charging capacitor for charging an output of the rectifying circuit via a separation diode, and a pair of serially connected serially connected to the charging capacitor. Switching element, a switch drive control circuit that outputs a high-frequency drive signal to each of the pair of switching elements, a coil connected to a connection point of the pair of switching elements, and a low potential side of the coil and the switching element. A discharge lighting load circuit in which a capacitor provided in series is connected in series, and a capacitor connected between a connection point of the coil and the discharge lighting load circuit and a positive output terminal of the rectifier circuit. It becomes.

According to a fifth aspect of the present invention, there is provided a drive signal in which the switch drive control circuit according to the first to sixth aspects changes a frequency corresponding to an increase or a decrease in the output voltage of the rectifier circuit within each half cycle of the AC power supply. Alternatively, the amplitude is changed so as to contradict the increase and decrease of the output voltage of the rectifier circuit within each half cycle of the AC power supply, and at least one of the drive signals is output.

[0013]

In the first aspect of the invention, the pulsating current output from the rectifier circuit is charged into the charging capacitor via the coil and the separating diode, and when one of the switching elements is turned on by the drive signal of the switch drive control circuit, the charging capacitor is charged. A high-frequency load current flows in the discharge lamp load circuit and the coupling capacitor based on the charging voltage of the rectifier circuit, and when the other switching element is turned on, the coupling capacitor is generated based on the back electromotive force generated in the coil connected to the positive output terminal of the rectifier circuit. Since the high-frequency load current flows through the discharge lamp load circuit and its switching element and the charging capacitor is charged via the separation diode, the back electromotive force generated in the coil causes the coupling capacitor, the discharge lamp load circuit, Each time a high-frequency load current flows through the switching element, The input current flows with respect to the current voltage, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or near the peak value, so that the input current waveform approaches the input voltage waveform and the input power factor is high. And the power supply harmonics decrease.

Further, the switch drive control circuit changes the drive signal or the amplitude of the frequency within each half cycle of the AC power supply corresponding to the increase or decrease of the output voltage of the rectifier circuit within each half cycle of the AC power supply. Since at least one of the drive signals whose width is changed so as to contradict the increase or decrease of the output voltage of the rectifier circuit is output, the frequency of the drive signal is higher when the output voltage of the rectifier circuit is higher, and the drive signal is lower when the output voltage is lower. Since the frequency becomes lower, the amplitude of the drive signal also becomes narrower when the output voltage is higher, or the amplitude of the drive signal also changes in accordance with the level of the output voltage of the rectifier circuit. In addition, the change in load current is kept small, the charging capacitor and the switching element have low withstand voltage, and the ripple of load current is small. It made.

[0015]

[0016]

In the second invention, the pulsating current output from the rectifying circuit is charged by a pair of coupling capacitors, and when one of the switching elements is turned on by a drive signal of the switch drive control circuit, the pulsating current output from the rectifying circuit is turned on. The current is charged to the charging capacitor via the separation diode, its switching element, the series circuit of the diode and the coil, and a high-frequency current flows to the discharge lamp load circuit and the coupling capacitor. Since a high-frequency load current flows through the discharge lamp load circuit and the switching element based on the voltage, each time a high-frequency current flows through the switching element, the discharge lamp load circuit, and the coupling capacitor, an input is made to the AC voltage of the AC power supply. Current flows and the input current is To flow in addition to the vicinity of the peak value,
The input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease. Also, when the charging capacitor is charged, a current flows through the charging capacitor through a series circuit of a diode and a coil in addition to the separating diode and the switching element, so that a large charging current, that is, an inrush current when the power is turned on is suppressed. Is done.

In the third aspect, the pulsating current output from the rectifying circuit is charged by a pair of coupling capacitors, and when one of the switching elements is turned on by a driving signal of the switch driving control circuit, the pulsating current output from the rectifying circuit is supplied. The current flows through the coil, the separation diode, the charging capacitor and its switching element, and the charging capacitor is charged.When the other switching element is turned on, the high frequency is applied to the switching element, the discharge lamp load circuit and the coupling capacitor based on the charging voltage of the charging capacitor. Since the load current flows through the coil, the input current flows with respect to the AC voltage of the AC power supply every time a high-frequency current for charging flows through the coil, the separation diode, the coupling capacitor, and the switching element. When the instantaneous value of the pulsating flow of the rectifier circuit is low or near the peak value To flow to the outside, the input current waveform approaches the input voltage waveform, the power supply harmonic is reduced with the input power factor becomes higher.

In the fourth aspect, the pulsating current output from the rectifier circuit is charged into the charging capacitor via the separation diode, and the charging capacitor is charged when one of the switching elements is turned on by the driving signal of the switching drive control circuit. A high-frequency load current flows through the switching element, the fluorescent lamp, and the coupling capacitor based on the voltage, and when the other switching element is turned on, a high-frequency current flows through the capacitor, the coil, and the switching element based on a pulsating flow from the rectifier circuit, and the fluorescent lamp also emits a fluorescent light. Since the high-frequency load current also flows through the coupling capacitor and the charging capacitor is charged via the isolation diode,
Each time a high-frequency current flows through a capacitor, a coil, a switching element, a fluorescent lamp, and a coupling capacitor, an input current flows with respect to an AC voltage of an AC power supply. Since the current flows other than the vicinity of the value, the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease. Fifth
In the invention of the second aspect, the switch drive control circuit according to the second to fourth inventions changes the frequency of the drive signal or the amplitude of the drive signal in accordance with the increase or decrease of the output voltage of the rectifier circuit in each half cycle of the AC power supply. By outputting at least one of the drive signals that have been changed in width to contradict the increase or decrease in the output voltage of the rectifier circuit within each half cycle of the power supply,
In any of the discharge lamp lighting devices according to the second to sixth inventions, when the output voltage of the rectifier circuit is high, the frequency of the drive signal is high, and when the output voltage is low, the frequency of the drive signal is low. Also, when the output voltage is high, the voltage becomes narrower, or the amplitude of the drive signal changes in accordance with the level of the output voltage of the rectifier circuit. As a result, the charging capacitor and the switching element have low withstand voltage, and the ripple of the load current is reduced.

[0020]

【Example】

Embodiment 1 FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention, FIG. 2 is a circuit diagram showing a configuration of a switch drive control circuit of the device, and FIG. 3 is an operation of the switch drive control circuit of the device. And FIG. 4 is a waveform diagram of a voltage, a current, and a drive signal in each part of the device. In the figure, 21 is an AC power supply, 22 is a filter for removing high frequency components, 23 is a rectifier circuit composed of a diode bridge for full-wave rectification of the AC of the AC power supply 21, and 24 is connected to the positive output terminal of the rectifier circuit 23. This is a step-up coil. 25 is a separating diode connected in series to the coil 24, 26 is a charging capacitor connected to the rectifying circuit 23 via the coil 24 and the separating diode 25, and charges the output of the rectifying circuit 23; A pair of series-connected coupling capacitors provided between the connection point of the diode 25 and the negative output terminal of the rectifier circuit 23.

Reference numeral 29 denotes a diode connected between the cathode of the separation diode 25 and the connection point between the capacitors 27 and 28, and reference numeral 30 denotes a diode connected in parallel to the capacitor 28. 31 and 32 are a pair of series-connected switching elements connected in parallel to the charging capacitor 26;
Is a switch drive control circuit that controls on / off of the switching elements 31 and 32 at a high frequency. And a frequency modulation circuit 33b that outputs a drive signal having a corresponding pulse width. 34, 35 are flywheel diodes connected in parallel to the switching elements 31, 32, respectively.
Reference numeral 40 denotes a discharge lamp load circuit connected between the connection point of the switching elements 31 and 32 and the connection point of the capacitors 27 and 28, and a fluorescent lamp 42 which is a load element connected in series to the coil 41 and the coil 40. And a capacitor 43 connected in parallel to the fluorescent lamp 42. In addition, 3
Reference numerals 7 and 38 denote series-connected voltage-dividing resistors provided between the positive and negative output terminals of the rectifier circuit 23. These connection points are connected to the switch drive control circuit 33 via a connection line 39.

Next, the operation of the above embodiment will be described. The pulsating current rectified from the AC power supply 21 by the rectifying circuit 23 is supplied to the charging capacitor 2 via the coil 24 and the separation diode 25.
6 and a pair of coupling capacitors 27 and 28
Is also charged. Here, when the switching element 31 is turned on by the drive signal of the switch drive control circuit 33, a high-frequency load current flows through the switching element 31, the discharge lamp load circuit 40, and the coupling capacitor 28 based on the charging voltage of the charging capacitor 26. Flows. Also, a high-frequency load current flows through the separation diode 25, the switch element 31, and the discharge lamp load circuit 40 based on the voltage of the coupling capacitor 27. Next, when the switching element 32 is turned on by the drive signal of the switch drive control circuit 33, the coil 2 connected to the positive output terminal of the rectifier circuit 23
4, the coupling capacitor 27,
A high-frequency load current flows through the discharge lamp load circuit 40 and the switching element 32, and the charging capacitor 26 is charged via the separation diode 25. Further, a high-frequency load current flows through the discharge lamp load circuit 40 and the switch element 32 based on the voltage of the coupling capacitor 28. Such an operation is repeated alternately.

Each time a high-frequency load current flows through the coupling capacitor 27, the discharge lamp load circuit 40, and the switching element 32 due to the back electromotive voltage generated in the coil 24, an input current flows with respect to the AC voltage of the AC power supply. Since the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or other than near the peak value, the input current waveform approaches the input voltage waveform, the effective current decreases with respect to the average current, and the input power factor increases. And the power supply harmonics decrease. Since the filter 22 is provided between the AC power supply 21 and the rectifier circuit 23, it is possible to prevent harmonics included in the current output from the rectifier circuit 23 from returning to the AC power supply 21.

In the above description, the frequency of the drive signal for driving the switching elements 31 and 32 of the switch drive control circuit 33 is constant, that is, fixed. Since the connection point of the series-connected voltage dividing resistors 37 and 38 provided between the terminals is connected to the switch drive control circuit 33 via the connection line 39, the output from the rectifier circuit 23 is output to the switch drive control circuit 33. The divided voltage of the pulsating flow shown in FIG. 4A by the voltage dividing resistor 38 is input. Then, the frequency of the drive signal output from the switch drive control circuit 33 fluctuates according to the level of the divided voltage with respect to the predetermined frequency of the oscillation circuit 33a, as shown in FIG. (See FIG. 3), and accordingly, FIG.
As shown in (d) and (e), the amplitude of the drive signal is narrow when the divided voltage is high so as to be contrary to the level of the divided voltage.
Widens when the divided voltage is low. Accordingly, the step-up ratio with respect to the charging capacitor 26 is reduced and the load current is also reduced, so that the charging capacitor 26 and the switching elements 31 and 32 have low withstand voltages, and the ripple of the load current is reduced. FIG. 4F shows the waveform of the input current output from the rectifier circuit 23.

In this embodiment, the switch drive control circuit 3
3, a divided voltage of the output voltage of the pulsating current output from the rectifier circuit 23 is input, and the frequency of the drive signal of the switch drive control circuit 33 is changed according to the level of the divided voltage. Rectifier circuit 23 in switch drive control circuit 35
The same operation and effect can be obtained by inputting the input current output from.

FIG. 5 is a circuit diagram showing the configuration of another switch drive control circuit, FIG. 6 is a graph for explaining the operation of the switch drive control circuit, and FIG. 7 is a lighting of a discharge lamp having the switch drive control circuit. FIG. 3 is a waveform diagram of a voltage and a drive signal in each part of the device. In the switch drive control circuit 133 shown in FIG. 5, the oscillation circuit 133a outputs a drive signal of a predetermined frequency, whereas in the pulse width modulation circuit 133b, as shown in FIG. The pulse width of the drive signal is narrow when the divided voltage is high, and widened when the divided voltage is low so as to contradict the level of the output (see FIG. 6). Accordingly, the step-up ratio with respect to the charging capacitor 26 is reduced, and the load current is also reduced, so that the charging capacitor 26 and the switching elements 31, 3
2 has a low withstand voltage, and the load current ripple is reduced.

FIG. 8 is a circuit diagram showing the configuration of another switch drive control circuit, and FIG. 9 is a waveform diagram of drive signals of the switch drive control circuit. The switch drive control circuit 233 shown in FIG. 8 causes the oscillation circuit 63a to output a drive signal of a predetermined frequency, whereas the frequency modulation circuit 233b changes the output voltage of the rectifier circuit 23 according to the level of the divided voltage, In response to the drive signal from the frequency modulation circuit 233b, the pulse width modulation circuit 233c narrows the pulse width of the drive signal when the divided voltage is high so as to be contrary to the level of the divided voltage of the output voltage of the rectifier circuit 23, Output wide when the divided voltage is low. Therefore, the switch drive control circuit 23
3 outputs a drive signal whose frequency and pulse width are simultaneously varied in accordance with the level of the divided voltage of the output voltage of the rectifier circuit 23, so that the step-up ratio with respect to the charging capacitor 26 is further reduced and the load current is also reduced. The voltage can be kept small, the charging capacitor 26 and the switching elements 31 and 32 have low withstand voltage, and the ripple of the load current is reduced.

Embodiment 2 FIG. FIG. 10 is a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention. In this embodiment, a rectifier circuit 23 that performs full-wave rectification of the AC of an AC power supply 21 via a filter 22 and an output of the rectifier circuit 23 is a booster coil 2.
4, a charging capacitor 26 charged via the separation diode 25, a pair of switching elements 31 and 32 connected in series connected in parallel to the charging capacitor 26, and a high-frequency drive signal output to each of the switching elements 31 and 32. A fixed frequency switch drive control circuit 333;
Flywheel diodes 34 and 35 connected in parallel to switching elements 31 and 32, a pair of coupling capacitors 46 and 47 connected in series to charging capacitor 26, and a pair of switching elements 31 and 3 respectively.
A discharge lighting load circuit 40 provided between the connection point of the coil 2 and the connection point of the pair of coupling capacitors 46 and 47;
4 and a voltage supply line 48 connecting a connection point between the separation diode 25 and the connection point between the pair of switching elements 31 and 32.

In this embodiment, the pulsating current output from the rectifier circuit 23 is charged into the charging capacitor 26 via the coil 24 and the separating diode 25. Further, the pair of coupling capacitors 46 and 47 are also charged. When one of the switching elements 31 is turned on by the drive signal of the switch drive control circuit 333, a high-frequency load current flows through the discharge lamp load circuit 40 and the coupling capacitor 47 based on the charging voltage of the charging capacitor 26. At this time, the switching element 31 is also based on the voltage of the coupling capacitor 46.
, A load current flows to the discharge lamp load circuit 40. Next, when the other switching element 32 is turned on, based on the back electromotive force generated in the coil 24 connected to the positive output terminal of the rectifier circuit 23, the current is not supplied to the discharge lamp load circuit 40 but is supplied through the voltage supply line 48. Lever switching element 32
, And the charging capacitor 26 is charged via the separation diode 25. At this time, the switching element 3 is also based on the voltage of the coupling capacitor 47.
2, a load current flows to the discharge lamp load circuit 40. As described above, every time a high-frequency current flows through the switching element 32 via the voltage supply line 48 due to the back electromotive force generated in the coil 24, an input current flows with respect to the AC voltage of the AC power supply 21, and the input current is rectified. Since the instantaneous value of the pulsating current of the circuit 23 flows when the instantaneous value is low or near the peak value, the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease. The coupling capacitor 4
6 can work without it.

Embodiment 3 FIG. FIG. 11 is a circuit diagram of a discharge lamp lighting device according to a third embodiment of the present invention. This embodiment includes a rectifier circuit 23 for full-wave rectification of an AC power supply voltage of an AC power supply 21 via a filter 22, a partial smoothing circuit 50 for partially charging the output of the rectifier circuit 23 via a coil 49, and a partial smoothing circuit 50. A pair of series-connected switching elements 31 and 32 connected in parallel to the circuit 50; a fixed-frequency switch drive control circuit 333 that outputs a high-frequency drive signal to each of the pair of switching elements;
And a discharge lighting load circuit 40 having one terminal connected to a connection point between the pair of switching elements 31 and 32 and a flywheel diode 34 and 35 connected in parallel to the switching element 32, respectively.
And a coupling capacitor 46 connected between the other terminal of the discharge lighting load circuit 40 and the high potential side of the switching element 31. Note that the partial smoothing circuit 5
0 indicates capacitors 50a and 50b and diodes 50c and 5
0d and 50e.

In this embodiment, the rectifier circuit 23 rectifies the AC power supply voltage of the AC power supply 21, and the pulsating current output from the rectifier circuit 23 is partially charged by the partial smoothing circuit 50 via the coil 49, and the switch is driven. When one of the switching elements 32 is turned on by the drive signal of the control circuit 333, a high-frequency load current flows through the discharge lamp load circuit 40 via the coupling capacitor 46 based on the charging voltage of the partial smoothing circuit 50, and the pulsating current of the coil 49. Is higher than the charging voltage of the partial smoothing circuit 50, a high-frequency load current flows through the discharge lamp load circuit 40 based on the voltage of the coil 49, and charges the coupling capacitor 46 when the other switching element 31 is turned on. The high-frequency current is caused to flow through the discharge lamp load circuit 40 based on the applied voltage. Thus, even when the voltage of the pulsating current of the coil 49 is higher than the charging voltage of the partial smoothing circuit 50, the AC voltage of the AC power supply is changed every time a high-frequency load current flows through the discharge lamp load circuit 40 based on the voltage of the coil 49. On the other hand, the input current flows, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit 23 is low or other than near the peak value, so that the input current waveform approaches the input voltage waveform, and the input power factor increases. Power harmonics are reduced. Further, since the voltage charged in the partial smoothing circuit 50 is １ ／ of the voltage output from the rectifier circuit 23, the withstand voltage of the switching elements 31 and 32 can be low.

Embodiment 4 FIG. FIG. 12 is a circuit diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention. In this embodiment, a rectifier circuit 23 for full-wave rectification of the AC of an AC power supply 21 via a filter 22 and a pair of series-connected coupling capacitors 27 connected in parallel between the positive and negative output terminals of the rectifier circuit 23 are provided.
28, a pair of switching elements 31 and 32 connected in series to the positive and negative output terminals of the rectifier circuit 23 via the separation diode 25, and a pair of switching elements 3
A fixed frequency switch drive control circuit 333 that outputs a high frequency drive signal to each of the switching elements 1 and 32, flywheel diodes 34 and 35 connected in parallel to the switching elements 31 and 32, respectively, and a pair of switching elements 3.
The discharge lighting load circuit 40 provided between the connection point of the pair of coupling capacitors 27 and 28 and the connection point of the pair of switching elements 31 and 32 are connected via a diode 51 to the connection point of the pair of switching elements 31 and 32. A coil 52; a charging capacitor 54 connected between the coil 52 and the low potential side of the switching element 32;
And a bypass capacitor 55 connected in parallel to the pair of switching elements 31 and 32.

In this embodiment, the pulsating current output from the rectifier circuit 23 is charged by a pair of coupling capacitors 27 and 28,
When one of the switching elements 31 is turned on by the driving signal of the switching drive control circuit 333, the pulsating current output from the rectifier circuit 23 is supplied to the charging capacitor 54 via the series circuit of the separating diode 25, the switching element 31, the diode 51 and the coil 52. And the coupling capacitor 28 is charged via the switching element 31 and the discharge lighting load circuit 40. Next, when the other switching element 32 is turned on, a high-frequency load current flows to the discharge lamp load circuit 40 via the switching element 32 based on the voltage of the coupling capacitor 28. Thus, based on the pulsating voltage of the rectifier circuit 23, the switching element 31, the discharge lighting load circuit 40, and the coupling capacitor 2
8, the input current flows with respect to the AC voltage of the AC power supply every time the high-frequency current flows, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit 23 is low or other than near the peak value. Since the waveform approaches the input voltage waveform, the input power factor increases and the power supply harmonics decrease. When the charging capacitor 54 is charged, the charging capacitor 5
Since a current flows through the serial circuit of the diode 51 and the coil 52 in addition to the separating diode 25 and the switching element 31, a large charging current, that is, an inrush current flows when the power is turned on.

Embodiment 5 FIG. FIG. 13 is a circuit diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention. In this embodiment, a rectifier circuit 23 that performs full-wave rectification of an alternating current of an AC power supply 21 via a filter 22 and a pair of serially connected serially connected to the positive and negative output terminals of the rectifier circuit 23 via a boosting coil 24. Coupling capacitors 27 and 28 and a pair of coupling capacitors 2
A pair of serially connected switching elements 31 and 32 connected in parallel to the respective elements 7 and 28 via an isolation diode 25;
A fixed-frequency switch drive control circuit 333 that outputs a high-frequency drive signal to each of the pair of switching elements 31 and 32, and flywheel diodes 34 and 35 that are connected in parallel to the switching elements 31 and 32, respectively.
A discharge lighting load circuit 40 provided between a connection point of the pair of switching elements 31 and 32 and a connection point of the pair of coupling capacitors 27 and 28;
32, a charging capacitor 54 connected between the diode 51 and the high-potential side of the switching element 31, and a diode 51 connected between the coil 51 and the low-potential side of the switching element 32. Diode 5
3, a bypass capacitor 55 connected in parallel to the pair of switching elements 31 and 32, and a diode 56 provided between the positive output terminal of the rectifier circuit 23 and the connection point of the pair of switching elements 31 and 32. It is.

In this embodiment, the pulsating current output from the rectifier circuit 23 is coupled to the coupling capacitors 27 and 28 via the coil 24.
When one of the switching elements 32 is turned on by the drive signal of the switching drive control circuit 333, the pulsating coil 24, the separating diode 25, the charging capacitor 54, the diode 5
1. The charging capacitor 54 flowing through the switching element 32
Is charged, and when the other switching element 31 is turned on, based on the charging voltage of the charging capacitor 54,
A high-frequency load current flows through the discharge lamp load circuit 40 and the coupling capacitor 28 via the switching element 31, and the separation diode 2 is set based on the voltage of the coupling capacitor 27.
5. Discharge lamp load circuit 40 via switching element 31
Current flows through Thus, the coil 24, the separation diode 25, the charging capacitor 54, the switching element 32
Each time a high-frequency current for charging the charging capacitor 54 flows, an input current flows with respect to the AC voltage of the AC power supply,
Since the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or other than near the peak value, the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease. The diode 56 charges the coupling capacitor 27 based on the charging voltage of the charging capacitor 54 when the switching element 31 is turned on.

Embodiment 6 FIG. FIG. 14 is a circuit diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention, and FIG. 15 is a waveform diagram of voltages and currents at various parts of the device. In this embodiment, a rectifier circuit 23 for full-wave rectification of the AC of an AC power supply 21 via a filter 22 and an output of the rectifier circuit 23 are connected to a separation diode 2.
5, a pair of switching elements 31 and 32 connected in series to the charging capacitor 26, and a pair of switching elements 3 connected in parallel to the charging capacitor 26.
A fixed frequency switch drive control circuit 333 that outputs a high frequency drive signal to each of the switching elements 1 and 32, flywheel diodes 34 and 35 connected in parallel to the switching elements 31 and 32, respectively, and a pair of switching elements 3.
A coil 41 connected to connection points 1 and 32;
1 and a low-potential side of the switching element 32, and a discharge lamp 42 in which a capacitor 46 is connected in series, and a connection point between the coil 41 and the discharge lamp 42 and a positive output terminal of the rectifier circuit 23. And a capacitor 57 connected thereto. The discharge lighting load circuit 40 includes the coil 41, the discharge lamp 42, and the capacitor 43 connected in parallel to the discharge lamp 42.

This embodiment is different from the AC power supply 21 shown in FIG.
5 (a) is rectified by the rectifier circuit 23,
The pulsating current shown in FIG. 15B output from the rectifier circuit 23 is charged in the charging capacitor 26 via the separation diode 25. And the switching drive control circuit 33
When one of the switching elements 31 is turned on by the drive signal of No. 3, the switching element 31, the coil 41, the fluorescent lamp 42, and the coupling capacitor 46 are charged to the charging capacitor 26 based on the charging voltage shown in FIG. A high-frequency load current shown in c) flows. Next, when the other switching element 32 is turned on, the rectifying circuit 23 is turned on.
A high-frequency current flows through the capacitor 57, the coil 41, and the switching element 32 based on the pulsating flow from the rectifier circuit 23, and a high-frequency current also flows through the fluorescent lamp 42 and the coupling capacitor 46. 25, the charging capacitor 26 is charged. Thus, when the switching element 32 is turned on, the capacitor 57 and the coil 4 based on the pulsating current from the rectifier circuit 23.
1 and the switching element 32, the input current flows with respect to the AC voltage of the AC power supply 21 each time the high-frequency current also flows through the fluorescent lamp 42 and the coupling capacitor 46. When the instantaneous value of the pulsating flow is low or flows other than near the peak value, the input current waveform approaches the input voltage waveform as shown in FIG. 15E, the input power factor increases, and the power supply harmonics decrease. Become. When a high-frequency current flows through the capacitor 57, the coil 41, and the switching element 32, the capacitor 5
7, the high-frequency current flows even when the voltage of the pulsating current from the rectifier circuit 23 is lower than the voltage of the charging capacitor 26, and the input current waveform becomes closer to the input voltage waveform, so that the input power factor is further increased. Become.

The switch drive control circuit 333 according to the second embodiment shown in FIG. 10 to the sixth embodiment shown in FIG. 14 outputs a drive signal having a fixed frequency.
In each embodiment, the switch drive control circuit 33 shown in FIG. 2, the switch drive control circuit 133 shown in FIG. 5, or the switch drive control circuit 233 shown in FIG. Needless to say, the ratio is reduced and the load current is reduced, the charging capacitor and the switching element need only have low withstand voltage, and the ripple of the load current is reduced. FIG. 16 shows the waveforms of the voltage, current, and drive signal of each part when frequency control is performed on the third embodiment shown in FIG. 11 using the switch drive control circuit 33 shown in FIG. Show. In this case, the frequency of the drive signal output from the switch drive control circuit 33 changes according to the fluctuation of the power supply voltage as shown in FIG. 16C, and the input current has the waveform shown in FIG. Flows in

[0039]

According to the first aspect of the present invention, the pulsating current output from the rectifier circuit is charged into the charging capacitor via the coil and the separating diode. When one of the switching elements is turned on, the discharge lamp is based on the charging voltage of the charging capacitor. When a high-frequency load current flows through the load circuit and the coupling capacitor, and the other switching element is turned on, the coupling capacitor, the discharge lamp load circuit, and the like are generated based on the back electromotive force generated in the coil connected to the positive output terminal of the rectifier circuit. Since the high-frequency current flows through the switching element and the charging capacitor is charged via the separation diode, the high-frequency current flows through the coupling capacitor, the discharge lamp load circuit, and the switching element due to the back electromotive force generated in the coil. The input current flows with respect to the AC voltage of the AC power supply every time, and the input current Since the flow in addition to the vicinity or when the peak value instantaneous value is low pulsating approaches the input current waveform is the input voltage waveform has the effect that the power supply harmonic is reduced with the input power factor becomes higher. Also, the switch drive control circuit changes the frequency of the drive signal or the amplitude of the rectifier circuit in each half cycle of the AC power supply, in accordance with the increase or decrease in the output voltage of the rectifier circuit in each half cycle of the AC power supply. Since at least one of the drive signals that are changed in width to contradict the increase and decrease of the output voltage is output, the frequency of the drive signal is high when the output voltage of the rectifier circuit is high, and the frequency of the drive signal is low when the output voltage is low. Accordingly, the amplitude of the drive signal also decreases when the output voltage is high, or the magnitude of the drive signal changes in accordance with the level of the output voltage of the rectifier circuit. In addition, the change in load current is also kept small, the charging capacitor and the switching element have low withstand voltage, and the load current ripple is small. It has the effect of that.

[0040]

[0041]

According to a second aspect of the present invention, the pulsating current output from the rectifier circuit is charged by a pair of coupling capacitors, and when one of the switching elements is turned on, the pulsating current output from the rectifying circuit is separated by a separating diode, its switching element, A charging capacitor is charged through a series circuit of a diode and a coil, and a high-frequency load current flows through the discharge lamp load circuit and the coupling capacitor, and when the other switching element is turned on, the discharge lamp load circuit based on the voltage of the coupling capacitor.
Since the high-frequency load current flows through the switching element, every time the high-frequency load current flows through the switching element, the discharge lamp load circuit, and the coupling capacitor, the input current flows with respect to the AC voltage of the AC power supply. Flows when the instantaneous value of the pulsating current of the rectifier circuit is low or near the peak value, the input current waveform approaches the input voltage waveform, the input power factor increases, and the power supply harmonics decrease. Also, when the charging capacitor is charged, a current flows through the charging capacitor through a series circuit of a diode and a coil in addition to the separating diode and the switching element, so that a large charging current, that is, an inrush current when the power is turned on is suppressed. It has the effect of being done.

According to a third aspect of the present invention, the pulsating current output from the rectifier circuit is charged by a pair of coupling capacitors via a coil,
When one switching element is turned on, the pulsating current output from the rectifier circuit flows through the coil, the separation diode, the charging capacitor and the switching element, and the charging capacitor is charged. When the other switching element is turned on, the charging voltage of the charging capacitor is charged. The high-frequency load current flows through the switching element, the discharge lamp load circuit and the coupling capacitor based on the following criteria. The input current flows with respect to the AC voltage of the power supply, and the input current flows when the instantaneous value of the pulsating current of the rectifier circuit is low or other than near the peak value, so that the input current waveform approaches the input voltage waveform and the input power factor And the harmonics of the power supply decrease.

According to a fourth aspect of the present invention, the pulsating current output from the rectifier circuit is charged into the charging capacitor via the separation diode, and when one of the switching elements is turned on, the switching element, the discharge lamp, When a high-frequency load current flows through the coupling capacitor and the other switching element is turned on, a high-frequency current flows through the capacitor, coil, and switching element based on the pulsating current from the rectifier circuit, and also a high-frequency load current flows through the discharge lamp and the coupling capacitor. Flows, and the charging capacitor is charged via the separation diode. Therefore, every time a high-frequency current flows through the capacitor, the coil, the switching element, the discharge lamp, and the coupling capacitor, the input to the AC voltage of the AC power supply is performed. The current flows, and the input current is the instant of the pulsating current in the rectifier circuit. Since the flow in addition or when the peak value near lower, closer to the input current waveform is the input voltage waveform has the effect that the power supply harmonic is reduced with the input power factor becomes higher.

In a fifth aspect of the present invention, the switch drive control circuit according to the second to fourth aspects changes the frequency of the drive signal in accordance with the increase or decrease of the output voltage of the rectifier circuit within each half cycle of the AC power supply. Alternatively, by outputting at least one of the drive signals whose amplitudes are changed in a wide and narrow manner in opposition to an increase and a decrease in the output voltage of the rectifier circuit in each half cycle period of the AC power supply, the second to sixth inventions In any of the discharge lamp lighting devices described above, the frequency of the drive signal is high when the output voltage of the rectifier circuit is high, the frequency of the drive signal is low when the output voltage is low, and the amplitude of the drive signal is accordingly small when the output voltage is high. Or the amplitude of the drive signal also changes in accordance with the level of the output voltage of the rectifier circuit. Changes in load current is also kept small,
The charging capacitor and the switching element need only have a low withstand voltage, and have the effect of reducing the ripple of the load current.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a switch drive control circuit of the device.

FIG. 3 is a graph for explaining the operation of the switch drive control circuit of the device.

FIG. 4 is a waveform diagram of a voltage, a current, and a drive signal in each part of the device.

FIG. 5 is a circuit diagram showing a configuration of another switch drive control circuit.

FIG. 6 is a graph for explaining the operation of the switch drive control circuit.

FIG. 7 is a waveform diagram of a voltage and a drive signal in each part of the discharge lamp lighting device having the switch drive control circuit.

FIG. 8 is a circuit diagram showing a configuration of another switch drive control circuit.

FIG. 9 is a waveform diagram of the switch drive control circuit.

FIG. 10 is a circuit diagram of a discharge lamp lighting device according to a second embodiment of the present invention.

FIG. 11 is a circuit diagram of a discharge lamp lighting device according to a third embodiment of the present invention.

FIG. 12 is a circuit diagram of a discharge lamp lighting device according to a fourth embodiment of the present invention.

FIG. 13 is a circuit diagram of a discharge lamp lighting device according to a fifth embodiment of the present invention.

FIG. 14 is a circuit diagram of a discharge lamp lighting device according to a sixth embodiment of the present invention.

FIG. 15 is a waveform diagram of a voltage and a current at each part of the device.

FIG. 16 is a waveform diagram of a voltage, a current, and a drive signal in each part when frequency control is performed in the same device in FIG. 11;

FIG. 17 is a circuit diagram of a conventional discharge lamp lighting device.

FIG. 18 is an input voltage and input current waveform diagram in a circuit of a conventional discharge lamp lighting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 AC power supply 23 Rectifier circuit 24 Coil 25 Separation diode 26 Charging capacitor 27 Coupling capacitor 28 Coupling capacitor 29 Diode 30 Diode 31 Switching element 32 Switching element 33 Switch drive control circuit 40 Discharge lamp load circuit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-54987 (JP, A) JP-A-5-64462 (JP, A) JP-A-4-364371 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 7/5387 H05B 41/24

Claims (5)

(57) [Claims] 1. A rectifier circuit for full-wave rectification of an alternating current of an AC power supply, a charging capacitor for charging an output of the rectifier circuit via a coil and a separating diode, and a pair of series-connected parallel-connected charging capacitors. A switching element;
A switch drive control circuit that outputs a high-frequency drive signal to each of the pair of switching elements; and a pair of series-connected couplings provided between a connection point between the coil and the separation diode and a negative output terminal of the rectifier circuit. A capacitor,
A discharge lighting load circuit provided between a connection point of the pair of switching elements and a connection point of the pair of coupling capacitors, and one of the pair of coupling capacitors is connected in parallel via a separation diode, and One includes a pair of series-connected diodes directly connected in parallel, and the switch drive control circuit changes the frequency corresponding to the increase or decrease of the output voltage of the rectifier circuit within each half cycle period of the AC power supply. A discharge lamp lighting device characterized by outputting at least one of a drive signal and a drive signal whose amplitude is changed in a wide and narrow manner in opposition to an increase and a decrease in an output voltage of a rectifier circuit within each half cycle of an AC power supply. 2. A rectifier circuit for full-wave rectification of alternating current of an AC power supply.
And a pair of serially connected in parallel with the positive and negative output terminals of the rectifier circuit.
Column-connected coupling capacitors and the positive and negative output terminals of the rectifier circuit
A pair of series connected in parallel with the
A connected switching element and the pair of switches
Switch that outputs a high-frequency drive signal to each switching element
A connection point between the drive control circuit and the pair of switching elements
And a connection point between the pair of coupling capacitors.
Discharge lighting load circuit, and the pair of switching elements
A coil connected to the connection point via a diode, and
Connected between the coil and the low potential side of the switching element
The charging capacitor, the coil and the switch
A diode connected to the high-potential side of the
A discharge lamp lighting device characterized by the following. 3. A rectifier circuit for full-wave rectification of alternating current of an alternating current power supply.
And connected in parallel via a coil to the positive and negative output terminals of the rectifier circuit
And a pair of series-connected coupling capacitors
Connected in parallel to a pair of coupling capacitors via an isolation diode
A pair of switching elements connected in series,
Each drive signal of a high frequency to a pair of switching elements
A switch drive control circuit for outputting, and the pair of switches
Connection point of the switching element and the connection point of the pair of coupling capacitors
Between the discharge lighting load circuit and the pair of switches.
A diode connected to the connection point of the switching element and
Between the diode and the high potential side of the switching element.
The charging capacitor connected to the
Diode connected to the low potential side of the switching element
And a positive output terminal of the rectifier circuit and the pair of switches.
And a diode connected between the
A discharge lamp lighting device characterized by the following. 4. A rectifier circuit for full-wave rectification of alternating current of an alternating current power supply.
And charge the output of the rectifier circuit via the isolation diode
The charging capacitor is connected in parallel with the charging capacitor.
A pair of switching elements connected in series,
Output high-frequency drive signals to each switching element
Switch drive control circuit and the pair of switching
A coil connected to the connection point of the element;
Capacitor provided between switching element and low potential side
Is connected in series with the discharge lighting load circuit
The connection point of the lighting circuit and the positive output terminal of the rectifier circuit
And a capacitor connected between
Discharge lamp lighting device. 5. The switch drive control circuit according to claim 1, wherein said switch drive control circuit switches frequencies.
The output voltage of the rectifier increases during each half cycle of the
The drive signal or the amplitude changed in response to the
To increase or decrease the output voltage of the rectifier circuit within each half cycle of the
At least one of the drive signals that have been changed so that they contradict each other
5. The method according to claim 2, wherein the output is performed.
The discharge lamp lighting device as described in the above.