LED backlight driving module
View Patent ↗The instant disclosure relates to a LED backlight driving module. The driving module utilizes a plurality of second power isolation transformers interconnected to each other in series and connected to a secondary winding of a first power isolation transformer in parallel to produce a plurality of second driving signals with uniform current, and driving corresponding LED light bars with uniform brightness. Optionally, a base voltage circuit can be used to provide a base voltage with negative voltage level on the other end of LED light bars, so as to lower the positive voltage level of the second driving signals. Thus, it is beneficial that the LED backlight driving module provides higher power conversion efficiency and has lower design cost.
1. A LED backlight driving module for driving a plurality of LED light bars, comprising:
a main power stage generating a power signal;
a first stage isolation transformer unit coupled to the main power stage for receiving the power signal and outputting a first driving signal;
a second stage isolation transformer unit having a plurality of second power isolation transformers, wherein primary windings of the second power isolation transformers are interconnected in series, and first secondary-windings of the first stage isolation transformer unit and the second stage isolation transformer unit are connected in parallel, and a secondary winding of the second power isolation transformer generates a second driving signal corresponding to the first driving signal; and
a plurality of output rectifiers and filters individually coupled to the secondary winding of the corresponding second power isolation transformer to perform rectification and filtering on the corresponding second driving signal to drive the correspondingly coupled LED light bars;
wherein the first stage isolation transformer unit is composed of a plurality of first power isolation transformers, and primary windings of the first power isolation transformers are connected in series so that the first driving signals of a same current value are induced on secondary windings of the first power isolation transformers respectively corresponding to the primary windings of the first isolation transformers.
2. The driving module of claim 1 , wherein the plurality of the second driving signals have the same current value, which drive the corresponding LED light bars to generate a uniform luminance.
3. A LED backlight driving module, for driving a plurality of LED light bars, comprising:
a main power stage generating a power signal;
a first stage isolation transformer unit coupled to the main power stage for receiving the power signal and using a first secondary-winding to induce a first driving signal;
a second stage isolation transformer unit having a plurality of second power isolation transformers, wherein the first secondary-winding of the first stage isolation transformer unit and the second stage isolation transformer unit are connected in parallel, wherein a secondary winding of the second power isolation transformer generates a second driving signal corresponding to the first driving signal;
a plurality of output rectifiers and filters respectively coupled to the secondary windings of the corresponding second power isolation transformers to perform rectification and filtering on the corresponding second driving signals, wherein each of the corresponding output rectifiers and filters are coupled to a first end of the corresponding LED light bar; and
a base voltage circuit coupled to a second end of the corresponding LED light bar, wherein a negative-voltage terminal of a second secondary-winding of the first stage isolation transformer unit induces a base voltage, and the coupled LED light bars are driven with the corresponding second driving signals.
4. The driving module of claim 3 , wherein each of the LED light bars has a breakover voltage error, and the voltage level of the second driving signal is 1.5 to 2.5 times of the breakover voltage error.
5. The driving module of claim 3 , wherein the base voltage has a negative voltage level.
6. A LED backlight driving module, for driving a plurality of LED light bars, comprising:
a main power stage generating a power signal;
a first stage isolation transformer unit coupled to the main power stage for receiving the power signal and outputting a first driving signal;
a second stage isolation transformer unit having a plurality of second power isolation transformers, wherein primary windings of the second power isolation transformers are interconnected in series and then connected to a first secondary-winding of the first stage isolation transformer unit in parallel, wherein the secondary winding of the second power isolation transformer generates a second driving signal corresponding to the first driving signal;
a plurality of output rectifiers and filters correspondingly coupled to the secondary windings of the second power isolation transformers to perform rectification and filtering on the corresponding second driving signals, wherein each of the corresponding output rectifiers and filters are coupled to a first end of the corresponding LED light bar; and
a base voltage circuit coupled to second ends of the plurality of LED light bars, wherein a negative-voltage terminal of a second secondary-winding of the first stage isolation transformer unit induces a base voltage, and the plurality of LED light bars are driven with the corresponding second driving signals.
7. The driving module of claim 6 , wherein the plurality of the second driving signals have the same current value, which drive the LED light bars to generate a uniform luminance.
8. The driving module of claim 6 , wherein the first stage isolation transformer unit is composed of a plurality of first power isolation transformers, and primary windings of the first isolation transformers are connected with each other in series, and the first driving signals of a same current value are induced on the corresponding first secondary-windings.
9. The driving module of claim 6 , wherein each LED light bar has a breakover voltage error, and the voltage level of the second driving signal is 1.5 to 2.5 times of the breakover voltage error.
10. The driving module of claim 6 , wherein, the base voltage has a negative voltage level.