DC-DC converter and driving device of light source for display device using the same
View Patent ↗A DC-DC converter includes a plurality of boost circuits and a controller. The boost circuits are coupled to another in parallel. The boost circuits receive a DC voltage and boost the DC voltage. The controller drives the boost circuits with a duty ratio of less than 50% and different phases.
1. A DC-DC converter comprising:
a plurality of boost circuits coupled in parallel with one another, receiving a DC voltage, and boosting the DC voltage; and
a controller configured to drive each boost circuit with a duty ratio of less than 50% and with different phases.
2. The DC-DC converter of claim 1 , wherein a first one of the boost circuits and a second one of the boost circuits are driven with a phase difference of 180 degrees.
3. The DC-DC converter of claim 2 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting a boosted DC voltage, and
the first boost circuit includes:
a first inductor connected to the input terminal;
a first diode having one terminal connected to the output terminal and the other terminal connected to the first inductor; and
a first switching element having an output terminal connected between the first inductor and the first diode, and
the second boost circuit includes:
a second inductor connected to the input terminal;
a second diode including one terminal connected to the output terminal and the other terminal connected to the second inductor; and
a second switching element having an output terminal connected between the second inductor and the second diode.
4. The DC-DC converter of claim 3 , wherein
a first signal having a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal having a duty ratio of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
5. The DC-DC converter of claim 2 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting a boosted DC voltage, and
the first boost circuit includes:
a first inductor connected to the input terminal;
a second inductor connected to the first inductor;
a first diode coupled in series between the output terminal and the second inductor; and
a first switching element having an output terminal connected between the first inductor and the second inductor, and
the second boost circuit includes:
a third inductor connected to the input terminal;
a fourth inductor connected to the third inductor;
a second diode coupled in series between the output terminal and the fourth inductor; and
a second switching element having an output terminal connected between the third inductor and the fourth inductor.
6. The DC-DC converter of claim 5 , wherein
a first signal having a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal having a duty ratio of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
7. The DC-DC converter of claim 2 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting the boosted DC voltage, and
the first boost circuit includes:
a first switching element having an input terminal connected to the input terminal;
a first inductor having one terminal connected to the output terminal of the first switching element and the other terminal connected to the output terminal; and
a first diode having one terminal between the output terminal of the first switching element and the first inductor, and
the second boost circuit includes:
a second switching element having an input terminal connected to the input terminal;
a second inductor having one terminal connected to the output terminal of the second switching element and the other terminal connected to the output terminal; and
a second diode having one terminal connected between the output terminal of the second switching element and the second inductor.
8. The DC-DC converter of claim 7 , wherein
a first signal having a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal having a duty ratio of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
9. A light source for a display device, comprising:
a DC-DC converting unit including a plurality of boost circuits coupled in parallel with one another and receiving a DC voltage for boosting;
a light source unit receiving a power source from the DC-DC converting unit and providing light to the display device; and
a controller controlling the boost circuits to have a duty ratio of less than 50% and different phases.
10. The light source of claim 9 , wherein the controller controls a first one of the boost circuits and a second one of the boost circuits to have a phase difference of 180 degrees.
11. The light source of claim 10 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting a boosted DC voltage, and
the first boost circuit includes:
a first inductor connected to the input terminal;
a first diode having one terminal connected to the output terminal and the other terminal connected to the first inductor; and
a first switching element having an output terminal connected between the first inductor and the first diode, and
the second boost circuit includes:
a second inductor connected to the input terminal;
a second diode including one terminal connected to the output terminal and the other terminal connected to the second inductor; and
a second switching element having an output terminal connected between the second inductor and the second diode.
12. The light source of claim 11 , wherein
a first signal having a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal having a duty of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
13. The light source of claim 10 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting a boosted DC voltage, and
the first boost circuit includes:
a first inductor connected to the input terminal;
a second inductor connected to the first inductor;
a first diode coupled in series between the output terminal and the second inductor; and
a first switching element having an output terminal connected between the first inductor and the second inductor, and
the second boost circuit includes:
a third inductor connected to the input terminal;
a fourth inductor connected to the third inductor;
a second diode coupled in series between the output terminal and the fourth inductor; and
a second switching element having an output terminal connected between the third inductor and the fourth inductor.
14. The light source of claim 13 , wherein:
a first signal with a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal with a duty ratio of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
15. The light source of claim 10 , wherein
the DC-DC converter includes an input terminal receiving a DC voltage and an output terminal outputting a boosted DC voltage, and
the first boost circuit includes:
a first switching element having an input terminal connected to the input terminal;
a first inductor having one terminal connected to the output terminal of the first switching element and the other terminal connected to the output terminal; and
a first diode having one terminal between the output terminal of the first switching element and the first inductor, and
the second boost circuit includes:
a second switching element having an input terminal connected to the input terminal;
a second inductor having one terminal connected to the output terminal of the second switching element and the other terminal connected to the output terminal; and
a second diode having one terminal connected between the output terminal of the second switching element and the second inductor.
16. The light source of claim 15 , wherein
a first signal having a duty ratio of less than 50% is applied to a control terminal of the first switching element,
a second signal having a duty ratio of less than 50% is applied to a control terminal of the second switching element, and
a phase difference between the first and second signals is 180 degrees.
17. A driving device for a light source of a display device, comprising:
a plurality of voltage converters connected in parallel with one another, wherein the voltage converters are one of boost converters, flyback converters, buck converters, forward converter, or buck-boost converters; and
a controller configured to drive each voltage converter with a duty ratio of less than 50% and with different phases,
wherein an output of the voltage converters provides a power source to the light source.
18. The driving device of claim 17 , wherein a first one of the voltage converters and a second one of the voltage converters are driven with a phase difference of 180 degrees.
19. The driving device of 18 , wherein the controller applies a signal having a duty ratio of less than 50% to a control terminal of a switching element of each voltage converter.
20. The driving device of claim 17 , wherein the controller also controls the light source.