LED driver and illumination system related to the same

Abstract

A driver includes a semiconductor chip, a bridge rectifier, and a current driver. The semiconductor chip includes a rectifying diode and a constant current source formed thereon. The bridge rectifier includes the rectifying diode. The current driver includes the first constant current source to provide a constant current.

What is claimed is: 
     
       1. A driver for connecting to a power line and a ground power line, comprising:
 a buffer layer, comprising a GaN based material; 
 a bridge rectifier formed on the buffer layer, comprising a rectifying diode, wherein the rectifying diode comprises a first high electron mobility transistor and a metal strip, wherein the first high electron mobility transistor comprises a gate and a first mesa providing a 2D-electron gas, and the metal strip is in Schottky contact with the first mesa, wherein the gate of the first high electron mobility transistor is electrically connected to the metal strip; and 
 a constant current source formed on the buffer layer, comprising a second mesa providing another 2D-electron gas, wherein the first constant current source is connected between the power line and the ground power line electrically connected to the rectifying diode and configured to provide a constant current. 
 
     
     
       2. The driver according to  claim 1 , wherein the constant current source further comprising comprises a high electron mobility transistor within the constant current source, wherein the high electron mobility transistor has a first arm, having a gate area, a first arm on a side of the gate area and a second arm on a an opposite side of the gate area opposite to the first arm. 
     
     
       3. The driver according to  claim 2 , wherein the first arm, the gate area and the second arm are patterned from a same metal layer. 
     
     
       4. A driver, comprising:
 a bridge rectifier; 
 a first thermistor and a second thermistor, wherein the second thermistor has a temperature coefficient different from that of the first thermistor; 
 a first constant current source electrically connected to the first thermistor in parallel; 
 a second constant current source electrically connected to the second thermistor in parallel; and 
 a third constant current source; 
 wherein the bridge rectifier includes an end connected to the first constant current source, the second constant current source and the third constant current source are connected to the rectifier. 
 
     
     
       5. The driver according to  claim 4 , wherein the first thermistor has a positive temperature coefficient. 
     
     
       6. The driver according to  claim 4 , wherein the first constant source further comprising comprises an enhance mode high electron mobility transistor within the first constant current source, wherein the enhance mode high electron mobility transistor has having a cover layer, an insulation layer, and a modification area. 
     
     
       7. The driver according to  claim 6 , wherein the modification area has a width narrower than that of the insulation layer. 
     
     
       8. The driver according to claim 1, further comprising a base,
 wherein the buffer layer is formed on a base and comprises a continuous surface, and   wherein the bridge rectifier and the constant current source are formed on the continuous surface.   
     
     
       9. The driver according to claim 8, wherein the base comprises a material different from that of the buffer layer. 
     
     
       10. The driver according to claim 9, wherein the constant current source comprises a material same as that of the buffer layer. 
     
     
       11. The driver according to claim 1, wherein each of the first mesa and the second mesa comprises a channel layer. 
     
     
       12. The driver according to claim 11, wherein the 2D-electron gas is formed in the channel layer of the first mesa, and the another 2D-electron gas is formed in the channel layer of the second mesa.