Patent Application
20100156314
(1) Field of the Invention
The invention relates to a light source driver circuit, and more particularly to a light source driver circuit, which determines whether to drive a light source or not using at least one switch and a control module.
(2) Description of the Prior Art
In the prior art, a control circuit for controlling a light-emitting diode (LED) includes a controller and an electronic switch Q, as shown in
In view of this, a light source driver circuit is required to eliminate the drawback of the prior art.
The invention provides a light source driver circuit, which determines whether to drive a light source or not using at least one switch and/or a control module.
In addition, the invention provides a light source driver circuit, in which a transformer module drives a plurality of light sources, and a surge voltage protection device is provided to prevent a control module from being damaged so that the surge voltage is only associated with an external element.
Furthermore, the invention provides a light source driver circuit, in which a first switch serves as a starting device, and a signal generator is provided to control a second switch so that the high efficiency driving can be obtained.
In one embodiment, the invention provides a light source driver circuit, which includes a voltage input terminal, a light source module, a transformer module, a voltage regulator module, a first switch and a control module. The voltage input terminal receives an input voltage. The light source module includes a plurality of light-emitting units. The transformer module is electrically connected to the plurality of light-emitting units. The voltage regulator module connected to the voltage input terminal provides a stable output voltage. The first switch electrically connected to the transformer module and the voltage regulator module receives the stable output voltage, and determines whether to turn on the first switch or not. The control module is electrically connected to the first switch. The control module and the first switch are controlled so that the input voltage can drive the light source module.
Further aspects, objects, and desirable features of the invention will be better understood from the detailed description and drawings that follow in which various embodiments of the disclosed invention are illustrated by way of examples.
The invention discloses a light source driver circuit, in which at least one switch and/or a control module may be provided to determine whether to drive a light source or not, a transformer module is provided to drive a plurality of light sources, and a surge voltage protection device is provided to prevent the control module from being damaged so that the surge voltage is only associated with an external element. In order to complete the description of the invention, illustrations will be made with reference to
More particularly, the control of the control module 212 may be implemented by using a lower voltage control device and may further be effectively controlled in conjunction with a second switch (not shown) so that the efficient driving can be achieved. In addition, if the instantaneously too-high voltage is inputted in this embodiment, it is possible to ensure that the control module 212 is free from being damaged.
The input voltage Vi may be generated from the mains, a primary battery or a secondary battery. If the mains (AC power) are rectified by a rectifier circuit, the voltage or the current for driving the light source module 304 can be generated. The divided voltage is generated through the voltage regulator module 308. At the beginning, the regulator device 3086 has not yet entered the breakdown region to generate the breakdown voltage, and the input voltage Vi firstly charges the second capacitor 3084. When the voltage across two ends of the charged second capacitor 3084 is higher than the reverse bias voltage for enabling the regulator device 3086 to work, the regulator device 3086 is held at a certain constant voltage to provide the bias voltage for turning on the first switch 310. When the load needs the higher current, the current flowing through the regulator device 3086 is decreased. On the contrary, when the load needs the lower current, the current flowing through the regulator device is increased. Because the influence of the flowing current on the potential difference between two ends of the regulator device is very small, the voltage regulating effect can be achieved.
Meanwhile, the input voltage Vi is provided to the transformer module 306 and the light source module 304. However, the control module 312 has not yet controlled the second switch 3124 to turn on, so the transformer module 306 and the light source module 304 also have not yet been turned on. When the control module 312 turns on the second switch 3124, the input voltage Vi is provided to the transformer module 306 and the light source module 304. At this time, if the input voltage Vi is at the other half-wave, a doubled voltage (the input voltage Vi plus the back electromotive force generated by the inductor) is generated at the transformer module 306 and the light source module 304. At this time, a surge voltage protection device (the diode 3066) is provided to prevent the control module 312 from being damaged so that the surge voltage is only associated with the light source module 304.
New characteristics and advantages of the invention covered by this document have been set forth in the foregoing description. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention. Changes in methods, shapes, structures or devices may be made in details without exceeding the scope of the invention by those who are skilled in the art. The scope of the invention is, of course, defined in the language in which the appended claims are expressed.
