The patent's assignee is
News editors obtained the following quote from the background information supplied by the inventors: "A variety of electronic circuits are used to drive diode loads and, more particularly, to control electrical current through strings of series-connected light-emitting diodes (LEDs), which, in some examples, form an LED display, or, more particularly, a backlight for a display, for example, a liquid crystal display (LCD). It is known that individual LEDs have a variation in forward voltage drop from unit to unit. Therefore, the strings of series-connected LEDs can have a variation in forward voltage drop.
"Strings of series-connected LEDs can be coupled to a common switching regulator, e.g., a boost switching regulator, at one end of the LED strings, the switching regulator configured to provide a high enough voltage to supply each of the strings of LEDs. The other end of each of the strings of series-connected LEDs can be coupled to a respective current sink, configured to sink a relatively constant current through each of the strings of series-connected LEDs.
"It will be appreciated that the voltage generated by the common switching regulator must be a high enough voltage to supply the one series-connected string of LEDs having the greatest total voltage drop, plus an overhead voltage needed for proper operation of the respective current sink. In other words, if four series-connected strings of LEDs have voltage drops of 30 Volts, 30 Volts, 30 Volts, and 31 Volts, and each respective current sink requires at least one volt in order to operate, then the common boost switching regulator must supply at least 32 Volts."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "In one aspect, a circuit includes a switching regulator configured to provide power to a load, a current regulator circuit coupled to the load and a response circuit configured to provide a control signal to the switching regulator in response to electrical changes of the current regulator circuit. The control signal changes non-linearly with respect to the electrical changes at the current regulator circuit.
"In another aspect, a circuit includes a switching regulator configured to provide power to a load, a current regulator circuit coupled to the load and an adaptive response circuit. The adaptive response circuit includes an amplifier configured to provide a control signal to the switching regulator in response to electrical changes at the current regulator. The adaptive response circuit includes a first input and a second input coupled to the current regulator circuit and an adaptive regulation voltage circuit configured to provide a regulation voltage to the first input of the amplifier to maintain operability of the current regulator circuit. The adaptive regulation voltage circuit replicates electrical characteristics of the current regulator circuit.
DESCRIPTION OF THE DRAWINGS
"The foregoing features of the invention, as well as the invention itself may be more fully understood from the following detailed description of the drawings, in which:
"FIG. 1A is block diagram of a circuit to drive a load;
"FIG. 1B is a block diagram of an example of the circuit in FIG. 1A that includes a string of light emitting diodes (LEDs) as the load;
"FIG. 1C is a block diagram of another example of the circuit of FIG. 1A that includes multiple strings of LEDs as the load;
"FIG. 2A is a block diagram of an example of a non-linear response circuit and an example of a current regulator circuit;
"FIG. 2B is a graph of current versus change of current for an exponential inverting transconductance amplifier;
"FIG. 2C is a circuit diagram of an example of a DC-DC converter;
"FIG. 3A is a block diagram of other examples of the non-linear response and the current regulator circuits;
"FIG. 3B is a block diagram of a further example of the non-linear response circuit;
"FIG. 4 is a circuit diagram of a current sink circuit;
"FIG. 5 is a circuit diagram of a current detection circuit;
"FIG. 6A is block diagram of another circuit to drive the load;
"FIG. 6B is a block diagram of an adaptive response circuit; and
"FIGS. 7A and 7B are circuit diagrams of examples of adaptive regulation voltage circuits."
For additional information on this patent application, see: Szczeszynski, Gregory; Szaniawski, Matthew. Circuitry to Control a Switching Regulator. Filed
Keywords for this news article include: Electronics, Light-emitting Diode,
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