TWI418248B - Delay start circuit for high frequency generator of electrodeless discharges lamp and high frequency generator using the same - Google Patents

Description

Delay start circuit of induction lamp high frequency generator and high frequency generator using same

The present invention relates to a delayed start circuit for an induction lamp high frequency generator and a high frequency generator using the same. More particularly, it relates to a delay start circuit for an induction lamp high frequency generator which slows down the impact of a power supply power switch and enhances the reliability of the high frequency generator when the high voltage generator of the induction lamp is started, and a high frequency generator using the same.

In recent years, the industry has developed a new generation of lighting devices: the electrodeless lamp (also known as the magnetic lamp) is mainly operated by the basic principle of electromagnetic induction and gas discharge, and the energy is coupled into the bulb by high-frequency electromagnetic induction technology. Electromagnetic induction is generated inside, so that the ions in the bulb oscillate to emit visible light. Since the electrodeless lamp does not have the tungsten filament and the electrode of the conventional bulb, there is no traditional loss, and the utility model has a long service life (up to 100,000 hours or more) and high luminous efficiency. It has the advantages of good electricity, good color rendering, no flickering, soft light, no vibration, no voltage fluctuation, less heat dissipation, etc. It is impossible for old fluorescent lamps, power-saving lamps and other lighting devices, and energy-saving and high efficiency. Under the mainstream demand, the electrodeless lamp has the potential to replace the mainstream LED lamp to become the lighting mainstream of the next generation.

The electrodeless lamp can be mainly divided into three parts, a power supply circuit, a high frequency generator, and a bulb coated with three primary color phosphors. The principle of operation is to first convert the mains (ie, alternating current) into direct current, and then boost the direct current town to a predetermined specification of high-frequency electric energy, so that the high-frequency electric energy generates a strong magnetic field through the induction coil (coupler) at the center of the bulb. The avalanche ionization of the low-pressure mercury and the inert gas pre-filled in the bulb is plasma, and the excited mercury atoms in the plasma radiate ultraviolet rays of 254 nm in the ground state, the lamp The fluorescent powder on the inner wall of the gun is converted into visible light by ultraviolet radiation.

The high frequency generator is generally composed of a power factor correction circuit and a high frequency oscillation circuit. The former main function is to provide a stable voltage to the latter and reduce harmonic interference of the alternating current. The high frequency oscillating circuit is composed of a filter circuit, a high frequency self-oscillation circuit and a bootstrap floating voltage starting circuit. The high-frequency self-oscillation circuit provides a high-frequency voltage of the coupled inductor inside the lamp, and a high magnetic field is generated by the coupled inductor to excite the fluorescent gas discharge to cause the bulb to emit light.

However, before the output voltage of the power factor correction circuit reaches a predetermined set value, a high peak current surge occurs and a burst current occurs. If the electrodeless lamp is activated before the output voltage of the power factor correction circuit is established, the operation mode is started. The power device MOSFET (Metal Oxide Semiconductor Field Effect Transistor) tube of the power correction circuit generates a larger peak current, a longer boost time, damages the power supply switch, and reduces the high-frequency generator of the electrodeless lamp. reliability. Moreover, the fuse of the electrodeless lamp may be easily melted due to excessive instantaneous current, which affects the stability and reliability of the operation of the electrodeless lamp.

Accordingly, there is a great need for a high frequency generator for an electrodeless lamp that overcomes the above disadvantages.

As a result of extensive research on the high-frequency generator of the electrodeless lamp, the inventors have found that the above problem can be overcome by designing a delay starting circuit in the high-frequency generator, and thus the present invention has been completed.

The main object of the present invention is to provide an induction lamp high frequency generator delay for an induction lamp high frequency generator which can slow down the impact on the power switch of the power source, enhance the reliability of the high frequency generator, and make the electrodeless lamp operate more stably. A startup circuit and a high frequency generator having the delayed startup circuit.

A first object of the present invention is to provide a delay start circuit for use in a high frequency generation of an electrodeless lamp including a filter rectifier circuit, a power factor correction circuit, an inverter circuit, and a resonant circuit connected in series in series. The delay starting circuit is characterized in that a voltage dividing circuit electrically connected to the output power terminal of the power correcting circuit and having a grounding function is electrically connected to the output terminal of the voltage dividing circuit and the resonant circuit. The first capacitor.

According to the delay start circuit of the present invention, the method further includes a capacitor protection circuit including a first resistor and a diode, wherein the first resistor is connected in series with the diode and then connected in parallel with the first capacitor.

According to the delay start circuit of the present invention, the voltage dividing circuit further includes a second resistor and a third resistor sequentially connected in series between the positive terminal of the power factor correction circuit and the ground, and the first capacitor is connected to the first capacitor A connection point between the two resistors and the third resistor.

According to the delay starting circuit of the present invention, the power switch of the power factor correction circuit of the induction lamp high frequency generator can be slowed down during startup, thereby improving the working stability and reliability of the electrodeless lamp.

A second object of the present invention is to provide a high frequency generator for an electrodeless lamp, comprising: a filter rectifier circuit, a power factor correction circuit, an inverter circuit, and a resonant circuit of the electrodeless lamp high frequency generator, characterized in that Between the power factor correction circuit and the inverter circuit, the delay start circuit of the present invention is provided, and the delay start circuit includes a voltage dividing circuit electrically connected to an output power terminal of the power correction circuit and having a ground function. An electrical connection is coupled between the output of the voltage dividing circuit and the first capacitor between the resonant circuits.

The high-voltage generator of the electrodeless lamp according to the present invention, wherein the input end of the filter rectifier circuit is electrically connected to the outside, and the output end thereof is electrically connected to the input end of the power factor correction circuit, and the output end of the power factor correction circuit and the inverse The output end of the variable circuit is electrically connected, and the output end of the inverter circuit is electrically connected to the input end of the resonant circuit.

According to the electrodeless lamp high-frequency generator of the present invention, the delay-starting circuit further includes a capacitor protection circuit including a first resistor and a diode, wherein the first resistor is connected in series with the diode, and is connected in parallel to the first capacitor end.

According to the high-voltage generator of the electrodeless lamp of the present invention, the voltage dividing circuit in the delay starting circuit further includes a second resistor and a third resistor sequentially connected in series between the positive terminal of the power factor correcting circuit and the ground. The first capacitor is connected to a connection point of the second resistor and the third resistor.

The high-voltage generator of the electrodeless lamp according to the present invention further includes a high-frequency electromagnetic interference filter circuit connected between the power factor correction circuit and the inverter circuit.

An electrodeless lamp high frequency generator according to the present invention further includes a driving circuit connected between the high frequency electromagnetic interference filter circuit and the inverter circuit, and the driving circuit includes a transistor at the transistor The external resistive capacitor (RC) and a voltage regulator.

According to the electrodeless lamp high frequency generator of the present invention, the power factor correction circuit further includes a power factor controller, a peripheral RC element, a field effect transistor, a step-up transformer, a Zener diode, and a capacitor. The anode of the voltage regulator tube is respectively connected to the step-up transformer and the drain of the field effect transistor, the cathode is connected to the capacitor and grounded, and the gate of the field effect transistor is connected to the power factor controller. Its source is grounded.

A third object of the present invention is to provide an electrodeless lamp comprising a bulb and a high frequency generator coupled to the bulb, characterized in that the high frequency generator is a high frequency generator of the present invention as described above.

According to the delay start circuit of the high-voltage generator of the electrodeless lamp of the present invention, since the bypass delay start circuit is included in the high-frequency generator, the transient current can be prevented from being excessive, and the reliability of the high-frequency generator can be increased, thereby increasing the electrodeless lamp. Stability of operation.

The present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic view showing the electrodeless lamp of the present invention. As shown in FIG. 1, the electrodeless lamp 100 of the present invention includes a bulb (including a coupler) 20 and a high frequency generator 10 electrically connected to the bulb 20.

As for the high frequency generator 10 of the present invention, more specifically, as shown in FIG. 2, it includes: a filter rectifier circuit 11, a power factor correction circuit 12, an inverter circuit 13, and a resonance circuit 14. An input end of the filter rectifier circuit 11 is electrically connected to an external power source, and an output end thereof is electrically connected to an input end of the power factor correction circuit 12; and an output end of the power factor correction circuit 12 is further connected to the inverter circuit 13 The input end is electrically connected, the output end of the inverter circuit 13 is connected to the input end of the resonant circuit 14, and the output end of the resonant circuit 14 is electrically connected to the bulb 20 through a coupler (not shown). In addition, a protection circuit 15 and a driving circuit 18 are bypassed between the inverter circuit 13 and the resonant circuit 14, and the inverter circuit 13, the resonant circuit 14, the protection circuit 15, and the driving circuit 18 are formed into a A circuit loop, and between the power factor correction circuit 12 and the resonant circuit 14, is further bypassed with a delay start circuit 16.

Accordingly, in addition to protecting the circuit by the protection circuit 15 bypassed, the delay start circuit 16 can be provided, and the delay start circuit 16 can be passed before the voltage of the power factor correction circuit 12 is established. The voltage of the power factor correction circuit 12 is prevented from entering the working mode immediately, and the high peak current can be avoided, and the inverter circuit 13 can be started after the voltage of the power factor correction circuit 12 is established, thereby increasing the stability of the electrodeless lamp 100. Sex.

In the present invention, the filter rectifier circuit 11 further includes a filter circuit and a rectifier circuit; the filter circuit can use an electromagnetic interference (EMI) filter circuit and is connected to an external power source, the purpose of which is to prevent power noise from entering the circuit and interfering with Other electrical equipment blocks the noise input circuit in the circuit and affects the normal operation of the lamp. The rectifying circuit can use a general-purpose rectifying circuit, which is not limited in the present invention. For example, a bridge rectifier or the like can be used, and the bridge rectifier can rectify the alternating current to obtain a pulsed direct current power supply for the circuit operation. As for the rectifier circuit and the mechanism of its function, it is well known to those skilled in the art, and thus will not be described herein.

Furthermore, the power factor correction circuit 12 in the present invention can be an active power factor correction circuit (APFC), which can realize high power factor values and low harmonics, and reduce product interference to the commercial power. Make the product meet the requirements of the relevant harmonic standards.

As for the circuit diagram of the power factor correction circuit 12 of the high frequency generator of the present invention, as shown in FIG. 3, mainly by the power factor controller chip IC1, the MOSFET power tube Q1, the step-up transformer T4, and the ultra-high speed rectifier diode D2. The output capacitor C7 and the feedback loop are composed. The mode of action is as follows: When the MOSFET power tube Q1 is turned on, the ultra-high speed rectifier diode D2 is turned off, and the output capacitor C7 is discharged through the load. When the MOSFET power transistor Q1 is turned from on to off, the abrupt electromotive force generated by the transformer T4 turns on the ultra-high speed rectifier diode D2, and the energy storage in the transformer T4 is discharged through the ultra-high speed rectifier diode D2 to charge the output capacitor C7. Since the MOSFET power transistor Q1 and the ultra-high speed rectifier diode D2 are alternately turned on, the output current of the rectifier circuit continuously flows through the transformer T4. The double loop feedback control scheme is adopted in the present invention. The function of the inner loop feedback is to output the full-wave rectified output to the DC pulse voltage, and output it to the third pin of the power factor controller IC1 chip through the voltage divider composed of R2 and R10 to ensure the current through the transformer T4. The trajectory of the input voltage is changed according to the sinusoidal law. The outer loop feedback is used as feedback control for the output DC voltage of the APFC transformer. The DC output voltage is sampled by a voltage divider composed of R12, R3, and R9 and input to the first leg of the MC33262. The power factor controller IC1 outputs pulse width modulation (PWM) pulse-modulated MOSFET power tube. The conduction of Q1 is such that the product satisfies the requirements of THD while stabilizing the output voltage.

The power factor control circuit IC1 of the present invention can use a CRM controlled type MC33262 wafer. The MC33262 chip system controls the turn-on or turn-off of the MOSFET power tube by testing the input/output conditions and the inductor current zero-crossing test to achieve high PF value and low THD (Total Harmonic Distortion). In order to make the product produce as low a harmonic as possible to meet the requirements of UEC61000-3-2. Due to the control of the MC33262 chip, the input current changes closely following the input voltage, resulting in a smooth sine wave with almost no phase shift to ensure that the product power factor is higher than 0.98.

The high-voltage generator 10 of the present invention, as shown in FIG. 4, further includes a high-frequency EMI filter circuit 17 connected to the output positive terminal of the power factor correction circuit 12 and the inverse Between the variable circuits 13, the high frequency EMI filter circuit 17 includes capacitors C11, C12, inductors L1, L2, and an inductor coil T6. However, this structure of the high frequency EMI filter circuit 17 is merely illustrative and not limiting. In the present invention, various general purpose filter circuits can be used.

In addition, the delay starting circuit included in the electrodeless lamp high frequency generator 10 of the present invention, as shown in FIGS. 4 and 5, includes a voltage dividing circuit 161 and a first capacitor C17, and the voltage dividing circuit 161 is connected. A grounding function is provided between the output end of the high frequency EMI filter 17 and the ground, and the first capacitor C17 is connected between the output end of the voltage dividing circuit 161 and the resonant circuit 14. Through the delay starting circuit 16, the current impact on the power switching element of the power supply APFC circuit when the induction lamp high frequency generator 10 is started can be slowed down, thereby protecting the power factor correction circuit 12 and improving the operational stability and reliability of the electrodeless lamp 100.

Preferably, the delay starting circuit 16 further includes a capacitor protection circuit 162. The capacitor protection circuit 162 further includes a first resistor R17 and a diode D5. The first resistor R17 is connected in series with the diode D5, and the first capacitor C17 Parallel. The capacitor protection circuit 162 can shunt the peak current of the capacitor when an abnormal spike current surge occurs at the access point of the harmonic circuit to prevent the capacitor from being broken down and increase the reliability of the circuit.

Specifically, the voltage dividing circuit 161 includes a second resistor R15 and a third resistor R16 which are sequentially connected in series between the positive terminal of the output of the high frequency EMI filter circuit 17 and the ground. The first capacitor C17 is connected to the second capacitor. A connection point between the resistor R15 and the third resistor R16.

Next, the inverter circuit 13 included in the electrodeless lamp high-frequency generator 10 of the present invention will be described. The inverter circuit 13 can be a half bridge conversion circuit. Specifically, the half-bridge conversion circuit includes coupled coils T5A, T5B, T5C, MOSFET power transistors Q2, Q7, voltage regulators D11, D12, D14, D15 and their peripheral RC components, the coils T5A and T5C Connected through the inductor L7, the coil T5A is connected in parallel with the reverse-connected Zener diodes D11 and D12 and the series resistors R20 and R21, and is disposed between the source and the gate of the MOSFET power tube Q2; the coil T5C and the reverse The connected Zener diodes D14 and D15 and the series resistors R22 and R23 are connected in parallel between the source and the gate of the MOSFET power transistor Q7. The source of the MOSFET power transistor Q2 is connected to the drain of the MOSFET power transistor Q7, the gate is opposite to the driving circuit 18, the drain is connected to the output of the power factor correction circuit 12, and the gate of the MOSFET power transistor Q7 is connected. It is connected to the input terminal of the abnormality control circuit U52, and its source is grounded.

Specifically, the resonant circuit 14 includes an inductor L7 and a capacitor C20 connected in series, and one end of the inductor L7 is connected to the output end of the delay start circuit 16, and the other end is connected to the capacitor C20. The other end of the capacitor C20 is connected to the lamp. The tubes 17 are connected.

Preferably, the resonant circuit 14 further includes a resistor R26 that is coupled in parallel with the capacitor C20. When the power is off, the resistor R26 can assist the capacitor C20 to discharge, thereby protecting the capacitor C20.

The protection circuit 15 included in the electrodeless lamp high frequency generator 10 of the present invention further includes an open circuit protection circuit and an open circuit protection circuit for protecting the circuit when the bulb 20 is open and open. It can stop the MOSFET power tube by the half bridge conversion circuit to stop the alternate conduction, so that the resonance circuit 14 stops oscillating, thereby stopping the operation of the electrodeless lamp 100.

Preferably, the driving circuit 18 included in the electrodeless lamp high frequency generator 10 of the present invention further includes transistors Q4 and Q6 and their peripheral resistive capacitance elements C25, C26, R18, R19 and a Zener diode D4. The driving circuit 18 The input terminal is connected to the positive terminal of the power factor correction circuit 12 through the resistor R15, and the output terminal is connected to the gate of the MOSFET power transistor Q2 through the diode D9. The relatively stable DC signal outputted by the power factor correction circuit 12 causes the Zener diode D4 to be turned on, and the circuit composed of Q6 and Q4 and its surrounding RC components is quickly turned on from left to right, thereby accelerating the startup of the MOSFET power transistor Q2, reducing Switching loss.

When the electrodeless lamp 100 is in operation, the power source forms a pulsed direct current to the power factor correction circuit 12 via the filter rectifier circuit 11, and then the direct current first passes through the delay start circuit 16, and the delay circuit acts to cause the drive circuit 14 to The voltage across C17 gradually increases. When the voltage reaches the breakdown voltage of the voltage regulator D4, the circuit enters the startup mode, so that the driving circuit composed of the transistors Q6, Q4, the voltage regulator D4 and the surrounding RC components Fast turn-on from left to right, so that the MOSFET power tube Q2 is quickly started, and the MOSFET power tubes Q2 and Q7 are alternately turned on to form a high-frequency alternating current signal, which is resonantly outputted to the coupling electrode via the inductor L7 and the capacitor C20, and the coupled electrode generates a magnetic field to excite The fluorescent gas discharge causes the bulb 20 to emit light. At this time, the drive circuit 18 stops operating. After the delay circuit is activated 16 , the induction lamp 100 avoids the immediate start to enter the operating mode before the voltage of the power factor correction circuit 12 is established, so that the output of the power factor correction circuit 12 can be avoided before the output voltage is established to the set value. The higher peak current, that is, the peak current on the power device MOSFET power tube of the power factor correction circuit 12 is not too large, the duration is not too long, and the MOSFET power tube does not need to have a larger margin to prevent overcurrent. When burned, the possibility of the fuse being broken due to excessive current is reduced, thereby ensuring that the inverter voltage 12 is started after the voltage of the power factor correction circuit 12 is established, so that the product working stability is increased.

It should be understood that the drive circuit 18 and the protection circuit 15 of the electrodeless lamp of the present invention are non-essential circuits, but circuits that can be selected as appropriate, and the scope of the present invention is not limited to the two circuits.

The invention has been described in terms of a preferred embodiment of the invention, but the invention is not limited to the specific embodiments described above, and all modifications and changes may be made without departing from the scope of the invention.

10. . . High frequency generator

11. . . Filter rectifier circuit

12. . . Power factor correction circuit

13. . . Inverter circuit

14. . . Resonant circuit

15. . . protect the circuit

16. . . Delayed start circuit

161. . . Voltage dividing circuit

162. . . Capacitor protection circuit

17. . . Inductor

18. . . Drive circuit

20. . . light bulb

100. . . Lamp

Fig. 1 is a schematic view showing the electrodeless lamp of the present invention.

Fig. 2 is a schematic view showing the operation of the high frequency generator of the present invention.

Fig. 3 is a circuit diagram of a power factor correction circuit of the high frequency generator of the present invention.

Fig. 4 is a circuit diagram showing the operation of the high frequency generator of the present invention.

Figure 5 is an enlarged schematic diagram of the delayed start circuit of the present invention.

10. . . High frequency generator

11. . . Filter rectifier circuit

12. . . Power factor correction circuit

13. . . Inverter circuit

14. . . Resonant circuit

15. . . protect the circuit

16. . . Delayed start circuit

Claims (9)

A delay start circuit for: comprising: a filter rectifier circuit, a power factor correction circuit, an inverter circuit, and a resonant circuit high frequency generator connected in series, in series, the delay start circuit The method includes a voltage dividing circuit electrically connected to the power supply correcting circuit, and a voltage dividing circuit having a grounding function and a first capacitor electrically connected between the output end of the voltage dividing circuit and the resonant circuit. The delay start circuit of claim 1, further comprising a capacitor protection circuit including a first resistor and a diode, wherein the first resistor is connected in series with the diode, and then connected in parallel with the first capacitor. The delay start circuit of claim 1, wherein the voltage dividing circuit further comprises a second resistor and a third resistor sequentially connected in series between the positive end of the power factor correction circuit and the ground, and the first capacitor Connected to a connection point of the second resistor and the third resistor. A high frequency generator for an electrodeless lamp, comprising: a filter rectifier circuit, a power factor correction circuit, an inverter circuit, and a resonant circuit high frequency generator, wherein the power factor correction circuit and the Between the inverter circuits, there is a delay start circuit according to any one of claims 1 to 3, and the delay start circuit includes a positive end of the output power source electrically connected to the power correction circuit and has a grounding function. The voltage dividing circuit and a first capacitor electrically connected between the output end of the voltage dividing circuit and the resonant circuit. The high frequency generator of claim 4, wherein the input end of the filter rectifier circuit is electrically connected to the outside, and the output end thereof is electrically connected to the input end of the power factor correction circuit, and the output end of the power factor correction circuit is An output end of the inverter circuit is electrically connected, and an output end of the inverter circuit is electrically connected to an input end of the resonant circuit. The high frequency generator of claim 4, further comprising a high frequency electromagnetic interference filter circuit connected between the power factor correction circuit and the inverter circuit. The high frequency generator of claim 4, further comprising a driving circuit connected between the high frequency electromagnetic interference filtering circuit and the inverter circuit, wherein the driving circuit comprises a transistor A RC component (RC) and a Zener diode on the periphery of the transistor. The high frequency generator of claim 4, wherein the power factor correction circuit further comprises a power factor controller, a peripheral RC component, a field effect transistor, a step-up transformer, a Zener diode, and a capacitor. The anode of the Zener diode is respectively connected to the step-up transformer and the drain of the FET, the cathode is connected to the capacitor and grounded, and the gate of the FET is connected to the power factor controller and The source is grounded. An induction lamp comprising a bulb and a high frequency generator coupled to the bulb, characterized in that the high frequency generator is a high frequency generator according to any one of claims 4 to 8.