公开(公告)号：US07598800B2

公开(公告)日：2009-10-06

申请号：US11805523

申请日：2007-05-22

申请人： Gurjit S. Thandi ,  Dilip S ,  Hendrik Santo ,  Kien Vi

发明人： Gurjit S. Thandi ,  Dilip S ,  Hendrik Santo ,  Kien Vi

IPC分类号： G05F1/10

CPC分类号： G05F3/205

摘要： The present invention uses two transistors instead of a sensing resistor to provide a constant current source for a load such as an array of light emitting diodes (“LEDs”). In the present invention, a bias current is applied to a branch of the circuit. The drain-to-source voltages of two transistors are matched. The voltage at the gate of both transistors is controlled based on the bias current and the drain-to-source current of the first of the two transistors. The second of the two transistors is sized such that source current of the second transistor is a multiple of the source current of the first transistor for a given gate voltage. By the techniques of this invention, the load current in a circuit is efficiently kept constant at a multiple of the input bias current.

摘要翻译： 本发明使用两个晶体管代替感测电阻器来为诸如发光二极管阵列（“LED”）的负载提供恒定电流源。 在本发明中，偏置电流被施加到电路的支路。 两个晶体管的漏极 - 源极电压匹配。 基于两个晶体管中的第一个的偏置电流和漏极 - 源极电流来控制两个晶体管的栅极处的电压。 两个晶体管中的第二个的尺寸使得第二晶体管的源电流对于给定的栅极电压是第一晶体管的源极电流的倍数。 通过本发明的技术，电路中的负载电流被有效地保持恒定在输入偏置电流的倍数。

公开(公告)号：US20080170012A1

公开(公告)日：2008-07-17

申请号：US11652736

申请日：2007-01-12

申请人： Dilip S ,  Gurjit S. Thandi ,  Hendrik Santo ,  Kien Vi

发明人： Dilip S ,  Gurjit S. Thandi ,  Hendrik Santo ,  Kien Vi

IPC分类号： G09G3/32

CPC分类号： G09G3/3413 ,  G09G2320/064 ,  H05B33/0815 ,  H05B33/0827 ,  Y02B20/346

摘要： The present invention relates to displays that use LED strings for backlighting. A lead string is provided with continuous drive voltage and the non-lead strings are provided with pulsed drive pulses. The string having the highest forward voltage is selected as the lead string. Feedback information indicative of the currents flowing through the non-lead strings is used to determine the duty cycles of the voltage pulses provided to drive the non-lead strings. The non-lead strings are controlled using pulsed drive voltages to minimize power dissipation in the circuit.

摘要翻译： 本发明涉及使用LED串进行背光照明的显示器。 引线串具有连续驱动电压，非引线串提供脉冲驱动脉冲。 选择具有最高正向电压的串作为引线串。 指示流经非引线串的电流的反馈信息用于确定为驱动非引线串提供的电压脉冲的占空比。 使用脉冲驱动电压来控制非引线串，以最小化电路中的功耗。

公开(公告)号：US20080290933A1

公开(公告)日：2008-11-27

申请号：US11805523

申请日：2007-05-22

申请人： Gurjit S. Thandi ,  Dilip S. ,  Hendrik Santo ,  Kien Vi

发明人： Gurjit S. Thandi ,  Dilip S. ,  Hendrik Santo ,  Kien Vi

IPC分类号： G05F3/02

CPC分类号： G05F3/205

摘要： The present invention uses two transistors instead of a sensing resistor to provide a constant current source for a load such as an array of light emitting diodes (“LEDs”). In the present invention, a bias current is applied to a branch of the circuit. The drain-to-source voltages of two transistors are matched. The voltage at the gate of both transistors is controlled based on the bias current and the drain-to-source current of the first of the two transistors. The second of the two transistors is sized such that source current of the second transistor is a multiple of the source current of the first transistor for a given gate voltage. By the techniques of this invention, the load current in a circuit is efficiently kept constant at a multiple of the input bias current.

摘要翻译： 本发明使用两个晶体管代替感测电阻器来为诸如发光二极管阵列（“LED”）的负载提供恒定电流源。 在本发明中，偏置电流被施加到电路的支路。 两个晶体管的漏极 - 源极电压匹配。 基于两个晶体管中的第一个的偏置电流和漏极 - 源极电流来控制两个晶体管的栅极处的电压。 两个晶体管中的第二个的尺寸使得第二晶体管的源电流对于给定的栅极电压是第一晶体管的源极电流的倍数。 通过本发明的技术，电路中的负载电流被有效地保持恒定在输入偏置电流的倍数。

公开(公告)号：US20080290804A1

公开(公告)日：2008-11-27

申请号：US11805525

申请日：2007-05-22

申请人： Hendrik Santo ,  Gurjit S. Thandi ,  Dilip S ,  Kien Vi

发明人： Hendrik Santo ,  Gurjit S. Thandi ,  Dilip S ,  Kien Vi

IPC分类号： H05B41/36

CPC分类号： H05B33/0854

摘要： The present invention provides a controller for regulating current in LEDs in electronic displays. The controller uses temperature sensing diodes to detect changes in the LED ambient temperature. As the LED ambient temperature changes, the forward voltage of the temperature sensing diode decreases. A signal processor adjusts the current passing through the LEDs based on the temperature induced changes in the forward voltage of the temperature sensing diodes. The present invention can reduce costs over the present methods of regulating current in LEDs and may more easily be integrated into a single integrated circuit chip. The temperature sensing may also be implemented outside the integrated circuit chip.

摘要翻译： 本发明提供一种用于调节电子显示器中的LED中的电流的控制器。 控制器使用温度感应二极管来检测LED环境温度的变化。 随着LED环境温度的变化，温度感应二极管的正向电压降低。 信号处理器根据温度感应二极管正向电压的变化来调节通过LED的电流。 本发明可以降低LED中调节电流的现有方法的成本，并且可以更容易地集成到单个集成电路芯片中。 也可以在集成电路芯片之外实现温度感测。