CN201174811Y - Lamp tube driving device - Google Patents

Abstract

The utility model discloses a lamp tube driving device, contain transverter, first transformer, second transformer, fluorescent tube, the control unit and third transformer. The converter is used for converting the high-voltage side direct-current voltage into alternating-current voltage. The first transformer is coupled to the inverter and selectively boosts or lowers the alternating voltage to output a first output voltage. The second transformer is coupled to the first transformer and boosts the first output voltage to output a second output voltage. The lamp tube is coupled to the second transformer and is driven by the second output voltage. The control unit is used for outputting a control signal. The third transformer is coupled between the current converter and the control unit, and the control signal is transmitted to the current converter through the third transformer.

Description

Lamp driver

technical field

The utility model relates to a lamp tube drive device, in particular to a closed loop lamp tube drive device with a zero-voltage switching high-voltage converter and a double-stage LC resonance tank.

Background technique

The transformer (transformer) plays the role of power conversion and connection in the power transmission and distribution system. For example, power plants need to transmit power at high voltages (345KV, 161KV, and 69KV, etc.) during power transmission and distribution. 110V, these procedures must be achieved through a transformer. Many electrical appliances used in daily life also have internal transformers, or are equipped with external transformers to convert the 110V AC power supply to an appropriate voltage value, and then obtain a low-voltage DC working power supply through the rectification and filtering circuit. The principle is to use the cooperation of the primary side coil and the secondary side coil to adjust the input voltage to the required output voltage, and then achieve the required voltage for driving. Therefore, for many electrical equipment, the transformer is an indispensable component.

The lamp driving device in the prior art uses a transformer to boost the power signal from 400V on the primary side to 1200V on the secondary side to provide the lamp for use. However, in this configuration, in order to comply with the safety regulations, the driving transformer needs to have a safety distance of at least 18mm between the primary side and the secondary side. Therefore, if one driving transformer is to drive one lamp tube, the area of the driving circuit board composed of several driving transformers will become very considerable, and the cost will also be greatly increased.

However, in order not to expand the installation area of the driving circuit board and avoid cost increase, the lamp must be driven by the low-voltage side DC voltage. Please refer to FIG. 1 , which shows a schematic diagram of a lamp driving device 1 in the prior art. As shown in FIG. 1 , the lamp tube 16 is driven by a low-voltage DC voltage 10 through a low-voltage converter 12 and a driving transformer 14 . In addition, the lamp driving device 1 further includes a control unit 18 and a feedback controller 20 . Through the feedback controller 20, the control unit 18 can transmit a control signal to the low-voltage inverter 12 according to the information received by the feedback controller 20, and then control the lamp 16, wherein the control unit 18 is also coupled to the low-voltage DC voltage.

Due to the inability to effectively isolate the signal and voltage of the DC voltage on the high-voltage side from the DC voltage on the low-voltage side, under the safety regulations, the lamp driving device in the prior art cannot directly drive the lamp tube by the DC voltage on the high-voltage side, and cannot directly drive the lamp tube. The lamp tube of the high-voltage side DC voltage is regulated.

Therefore, the main purpose of the present invention is to provide a lamp driving device to solve the above problems.

Utility model content

An object of the present invention is to provide a lamp driving device, which mainly utilizes a double-stage LC resonance tank to cooperate with a high-voltage converter, which not only achieves the purpose of isolation and transformation, but also achieves the function of zero-voltage conversion. In addition, through signal isolation and voltage transformation, the lamp driving device can be controlled in a closed-loop manner through the control unit.

According to a specific embodiment, the lamp driving device includes an inverter, a first transformer, a second transformer, a lamp, a control unit and a third transformer. The converter is used to convert the DC voltage on the high voltage side into AC voltage. The first transformer is coupled to the converter, and selectively boosts or steps down the AC voltage to output a first output voltage. The second transformer is coupled to the first transformer, and boosts the first output voltage to output a second output voltage. The lamp is coupled to the second transformer and driven by the second output voltage. The control unit is used for outputting control signals. The third transformer is coupled between the converter and the control unit, and the control signal is transmitted to the converter through the third transformer.

Compared with the prior art, the utility model has at least the following advantages in practical application: 1) It achieves the function of isolating and transforming the high-voltage side and the low-voltage side, which complies with safety regulations; 2) It achieves zero-voltage switching of DC to AC, reducing Conversion power loss; 3) Through the design of isolated signal transformation, the control unit can control the lamp drive device in a closed loop under the safety regulations, thereby improving the safety and stability of the device.

The advantages and spirit of the present utility model can be further understood through the following detailed description of the utility model and accompanying drawings.

Description of drawings

Fig. 1 shows a schematic diagram of a lamp driving device in the prior art.

Fig. 2 shows a schematic diagram of the lamp driving device of the first specific embodiment of the present invention.

Fig. 3 shows a schematic diagram of a lamp driving device according to a second specific embodiment of the present invention.

Fig. 4 shows a schematic diagram of a lamp driving device according to a third specific embodiment of the present invention.

Fig. 5 shows a schematic diagram of a lamp driving device according to a fourth specific embodiment of the present invention.

Fig. 6 shows a schematic diagram of a lamp driving device according to a fifth specific embodiment of the present invention.

Fig. 7 shows a schematic diagram of a lamp driving device according to a sixth specific embodiment of the present invention.

Description of reference symbols

1, 3, 3', 5, 5', 7, 7': Lamp driving device

10: Low-voltage side DC voltage 12: Low-voltage converter

18, 38: Control unit 20, 44: Feedback control

30: High voltage converter 42: Capacitor

HD: DC voltage on high voltage side LD: DC voltage on low voltage side

14, 32, 34, 34', 40: Transformer

16, 36a, 36a', 36b, 36b', 36c, 36c', 36d, 36d': lamp tubes.

Detailed ways

Please refer to FIG. 2 . FIG. 2 shows a schematic diagram of a lamp driving device 3 according to a first embodiment of the present invention. As shown in Figure 2, the lamp driving device 3 includes a high-voltage converter 30, a first transformer 32, a second transformer 34, a first lamp 36a, a control unit 38, a third transformer 40, a capacitor 42, and a feedback controller 44.

The high-voltage converter 30 is used to convert the high-side DC voltage HD into an AC voltage. It should be noted that the DC voltage on the high-voltage side is a voltage obtained from the power supply terminal after type rectification and filtering, or a regulated voltage obtained by a power factor correction control circuit, so it is a non-isolated voltage.

The first transformer 32 is coupled to the high voltage converter 30 and can selectively step up or step down the AC voltage to output a first output voltage. In addition, the primary side winding of the first transformer 32 is coupled to the capacitor 42 to form a primary side resonant circuit. With the capacitor 42, the design of the first transformer 32 is relatively simplified, so that the first transformer 32 does not need to take into account the role of the secondary side resonance, and the volume of the first transformer 32 is therefore smaller, thereby reducing the manufacturing cost. .

More importantly, the first transformer 32 is matched with the circuit design of the high-voltage converter 30 after properly adjusting the gain of the resonant tank (for example: transformer leakage inductance, capacitance and turns ratio), when the DC voltage is converted to AC voltage , can achieve the effect of zero-voltage switching, thereby reducing the power loss of the switching transistor (MOSFET).

In addition, the first transformer 32 can achieve the purpose of isolation and transformation. For example, if the primary side input voltage of the first transformer 32 is 400V as an example, the secondary side output voltage of the first transformer 32 will be less than 400V, under the specified safety distance, the distance between the primary side and the secondary side of the first transformer 32 only requires a safety distance of 6 mm. Therefore, with the use of the first transformer 32 , the required safety distance for directly using the driving transformer can be effectively shortened, thereby reducing the installation area of the circuit board and solving the problem of high device cost.

The second transformer 34 is coupled to the first transformer 32 and boosts the first output voltage to output a second output voltage. The first light tube 36a is coupled to the secondary winding of the second transformer 34 and driven by the second output voltage. The first lamp tube 36a cooperates with the secondary side winding of the second transformer 34 to form a secondary side resonant circuit. In addition, after properly adjusting the gain of the resonant tank (for example: transformer leakage inductance, capacitance and turn ratio), the voltage value required for starting and working of the first lamp tube 36a can be obtained, and the optimal balance of the first lamp tube 36a can be adjusted. current, and can be matched with the first transformer 32 to achieve an optimal design.

The control unit 38 is used to output a control signal, which is output to the high-voltage converter 30 through the third transformer 40. The control signal includes a square wave signal of a specific frequency and duty cycle (duty), and can accept dimming control and start frequency conversion Control, lamp current feedback adjustment control and lamp open circuit and short circuit protection control.

In addition, there is a feedback controller 44 between the control unit 38 and the first lamp 36a coupled to the control unit 38 and the first lamp 36a to receive the voltage signal from the first lamp 36a and transmit the voltage signal to the control unit 38. In actual application, the feedback controller 44 can detect the state of the first lamp 36a, and convert and send back relevant information to the control unit 38, so as to implement mechanisms such as open circuit and short circuit protection control of the first lamp 36a.

The third transformer 40 is coupled between the high voltage converter 30 and the control unit 38 for receiving the control signal of the control unit 38 and transmitting it to the high voltage converter 30 through the third transformer 40 . It should be noted that after isolating and converting the control signal sent by the control unit 38 , the third transformer 40 provides complementary driving signals to the high voltage converter 30 , thereby achieving the purpose of signal isolation. More importantly, in this embodiment, the low-voltage side DC voltage LD is only coupled to the control unit 38. Compared with the prior art lamp driving device 1 (as shown in FIG. 1 ), the lamp driving device 3 not only With the function of isolating voltage, it can better achieve the purpose of signal isolation.

In this embodiment, the utility model mainly uses the double LC resonance tank design of the first transformer 32 and the second transformer 34 to cooperate with the high-voltage converter 30, not only to achieve the purpose of isolation and transformation, but also to achieve zero-voltage conversion function, the design can be optimized by properly adjusting the resonance tank gain and circuit design. In addition, with the signal isolation and transformation function provided by the third transformer 40, the lamp driving device 3 can be feedback-controlled by the control unit 38 in a closed-loop manner without violating safety regulations, which can further improve the safety of the device. of stability.

Please refer to FIG. 3 . FIG. 3 shows a schematic diagram of a lamp driving device 3 ′ according to a second specific embodiment of the present invention. As shown in FIG. 3 , the main difference between the lamp driving device 3 ′ and the lamp driving device 3 is that the lamp driving device 3 ′ further includes a second lamp 36 a ′ and a fourth transformer 34 ′. The primary winding of the fourth transformer 34' is coupled to the secondary winding of the first transformer 32, the second lamp 36a' is coupled to the secondary winding of the fourth transformer 34', and is coupled to the feedback control device 44. Thereby, the lamp driving device 3' can simultaneously drive the first lamp 36a and the second lamp 36a'. The working principle of the lamp driving device 3 ′ is the same as that of the lamp driving device 3 , and will not be repeated here.

Please refer to FIG. 4 , which shows a schematic diagram of a lamp driving device 5 according to a third embodiment of the present invention. As shown in FIG. 4 , the main difference between the lamp driving device 5 and the lamp driving device 3 is that the lamp driving device 5 further includes a second lamp tube 36b, and the second lamp tube 36b is connected to the secondary side of the second transformer 34. The winding is coupled to the feedback controller 44 . Thereby, the lamp driving device 5 can simultaneously drive the first lamp 36a and the second lamp 36b. The working principle of the lamp driving device 5 is the same as that of the lamp driving device 3 , and will not be repeated here.

Please refer to FIG. 5 . FIG. 5 shows a schematic diagram of a lamp driving device 5 ′ according to a fourth specific embodiment of the present invention. As shown in Figure 5, the main difference between the lamp driving device 5' and the lamp driving device 5 is that the lamp driving device 5' further includes a third lamp 36a', a fourth lamp 36b' and a fourth transformer 34' . The primary winding of the fourth transformer 34' is coupled to the secondary winding of the first transformer 32, and the third lamp 36a' and the fourth lamp 36b' are coupled to the secondary winding of the fourth transformer 34'. connected and coupled to the feedback controller 44. Thereby, the lamp driving device 5' can simultaneously drive the first lamp 36a, the second lamp 36b, the third lamp 36a' and the fourth lamp 36b'. The working principle of the lamp driving device 5' is the same as that of the lamp driving device 5, and will not be repeated here.

Please refer to FIG. 6 . FIG. 6 shows a schematic diagram of a lamp driving device 7 according to a fifth embodiment of the present invention. As shown in Figure 6, the main difference between the lamp driving device 7 and the lamp driving device 5 is that the lamp driving device 7 further includes a third lamp 36c and a fourth lamp 36d, and the second transformer 34 includes two secondary side winding, the first light tube 36a and the second light tube 36b are coupled to a secondary side winding of the second transformer 34, and are coupled to the feedback controller 44, the third light tube 36c and the fourth light tube 36d are connected to Another secondary winding of the second transformer 34 is coupled to the feedback controller 44 . Thereby, the lamp driving device 7 can simultaneously drive the first lamp 36a, the second lamp 36b, the third lamp 36c and the fourth lamp 36d. The working principle of the lamp driving device 7 is the same as that of the lamp driving device 5 , and will not be repeated here.

Please refer to FIG. 7 . FIG. 7 shows a schematic diagram of a lamp driving device 7 ′ according to a sixth embodiment of the present invention. As shown in Figure 7, the main difference between the lamp driving device 7' and the lamp driving device 7 is that the lamp driving device 7' additionally includes a fifth lamp 36a', a sixth lamp 36b', and a seventh lamp 36c. ', the eighth lamp tube 36d' and the fourth transformer 34'. The fourth transformer 34 ′ includes two secondary windings, the fifth lamp 36 a ′ and the sixth lamp 36 b ′ are coupled to one secondary winding of the fourth transformer 34 ′, and are coupled to the feedback controller 44 , the seventh light tube 36c ′ and the eighth light tube 36d ′ are coupled to the other secondary winding of the fourth transformer 34 ′, and are also coupled to the feedback controller 44 . Thereby, the lamp driving device 7' can simultaneously drive the first lamp 36a, the second lamp 36b, the third lamp 36c, the fourth lamp 36d, the fifth lamp 36a', and the sixth lamp 36b' , the seventh lamp tube 36c' and the eighth lamp tube 36d'. The working principle of the lamp driving device 7' is the same as that of the lamp driving device 7, and will not be repeated here.

Compared with the prior art, the utility model has at least the following advantages in practical application: 1) It achieves the function of isolating and transforming the high-voltage side and the low-voltage side, which complies with safety regulations; 2) It achieves zero-voltage switching of DC to AC, reducing Conversion power loss; 3) Through the design of isolated signal transformation, the control unit can control the lamp drive device in a closed loop under the safety regulations, thereby improving the safety and stability of the device.

Through the above detailed description of the preferred embodiments, it is hoped that the features and spirit of the present utility model can be described more clearly, and the scope of the present utility model is not limited by the preferred embodiments disclosed above. On the contrary, the purpose is to cover various changes and equivalent arrangements within the scope of the patent scope of the utility model. Therefore, the scope of the patent application for the utility model should be interpreted in the broadest way based on the above description, so as to cover all possible changes and equivalent arrangements.

Claims (6)

1. A lamp driving device, characterized in that the lamp driving device comprises: a converter for converting a high voltage side DC voltage into an AC voltage; a first transformer, coupled to the converter, selectively step-up or step-down the AC voltage to output a first output voltage; A second transformer, coupled to the first transformer, boosts the first output voltage to output a second output voltage; at least one lamp coupled to the second transformer and driven by the second output voltage; a control unit outputting a control signal; and A third transformer is coupled between the inverter and the control unit, and the control signal is transmitted to the inverter through the third transformer. 2. The lamp driving device as claimed in claim 1, wherein a capacitor is coupled to a primary winding of the first transformer to form a primary resonant circuit. 3. The lamp driving device as claimed in claim 1, wherein the lamp is coupled to a secondary side winding of the second transformer to form a secondary side resonant circuit. 4. The lamp driving device according to claim 1, further comprising a feedback controller, coupled between the control unit and the lamp, receiving a voltage signal from the lamp, and The voltage signal is passed to the control unit. 5. The lamp driving device according to claim 1, wherein the second transformer comprises a first secondary winding and a second secondary winding, the first secondary winding and The second secondary side windings are respectively coupled to at least one lamp tube. 6. The lamp driving device as claimed in claim 1, wherein the control signal comprises a square wave signal with a specific frequency and duty cycle.

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