Dc-dc converter, driving apparatus having dc-dc converter, and display device having driving apparatus

Abstract

A DC-DC converter includes a main inductor connected to an input voltage, a main switching element connected in series to the main inductor, a main diode connected to the main inductor and a load, and a main capacitor connected to the main diode and the load, the DC-DC converter changing the input voltage to output a changed input voltage as an output voltage. The DC-DC converter further includes an oscillator connected between the main inductor and the main diode, an auxiliary switching element connected to the oscillator, the auxiliary switching element changing an operation state based on an externally applied control signal to control the oscillator, and a diode unit connected to the oscillator and the auxiliary switching element and controlling current flow based on operations of the oscillator and the auxiliary switching element to change the output voltage. The main switching element and the main diode are to be zero voltage switching or zero current switching in accordance with the operations of the oscillator and the auxiliary switching element.

1 - 8 . (canceled)  
   
   
       9 . A driving apparatus of a display device including a light source unit having a plurality of light sources, the driving apparatus comprising: 
 a power supply applying a driving voltage for driving the light sources; and    a control signal outputting a first control signal controlling the power supply and a second control signal controlling the light sources, the driving apparatus controlling operations of the light sources by the driving voltage based on the second control signal,    wherein the power supply comprises a DC-DC converter having a main switching element, operation of the main switching element changed by the first control signal, a main diode connected to the light source unit, an oscillator connected between the main switching element and the main diode, and an auxiliary switching element connected to the oscillator and controlling operation of the oscillator, the DC-DC converter boosting an input DC voltage to the driving voltage by a predetermined magnitude and applying the boosted driving voltage to the light source unit,    wherein the DC-DC converter is to be zero voltage switching or zero current switching of the main switching element and the main diode in accordance with operations of the oscillator and the auxiliary switching element.    
   
   
       10 . The driving apparatus of  claim 9 , wherein the oscillator comprises: 
 a first capacitor connected in parallel to the main switching element;    a first inductor connected to the first capacitor; and    a second inductor connected between the first capacitor and the auxiliary switching element.    
   
   
       11 . The driving apparatus of  claim 9 , further comprising in the power supply a rectifier changing an externally supplied AC voltage into a DC voltage and a smoother smoothing the DC voltage from the rectifier and outputting the smoothed DC voltage as the input DC voltage to the DC-DC converter.  
   
   
       12 . The driving apparatus of  claim 11 , wherein the power supply further comprises a filter filtering noises included in the AC voltage.  
   
   
       13 . The driving apparatus of  claim 10 , wherein the DC-DC converter further comprises: 
 a third inductor connected to the input DC voltage;    a first diode connected to the auxiliary switching element and the first inductor;    a second diode connected to the second inductor; and    a second capacitor connected to the main diode and the second diode.    
   
   
       14 . The driving apparatus of  claim 9 , wherein the main switching element is a semiconductor device of a type different from that of the auxiliary switching element.  
   
   
       15 . The driving apparatus of  claim 14 , wherein the auxiliary switching element is a metal oxide silicon field effect transistor.  
   
   
       16 . The driving apparatus of  claim 9 , wherein the light sources comprise light emitting diodes of at least one red, green, and blue colors.  
   
   
       17 - 22 . (canceled)  
   
   
       23 . A display device including a plurality of pixels, a lamp unit emitting light based on a lamp control signal, and a power supply applying a driving voltage for driving the lamp unit, the display device comprising: 
 a main inductor connected to an input voltage;    a main switching element, the main switching element changing operation based on an externally applied control signal;    a main diode connected to the lamp unit;    an oscillator connected between the main switching element and the main diode; and    an auxiliary switching element connected to the oscillator and controlling the oscillator,    wherein the main switching element and the main diode are to be zero voltage switching or zero current switching in accordance with operations of the oscillator and the auxiliary switching element.    
   
   
       24 . The display device of  claim 23 , wherein the oscillator comprises: 
 a first capacitor connected in parallel to the main switching element;    a first inductor connected to the first capacitor; and    a second inductor connected between the first capacitor and the auxiliary switching element.    
   
   
       25 - 27 . (canceled)