Driving circuit for the LED charge pump

Abstract

This invention relates to one method to alternate charge phase and discharge phase with charge pump into input voltage source as drive voltage to supply the light diode, wherein, current set unit determines one reference current; the current adjust unit has current adjust terminal and feedback test end; the current adjust terminal is coupled to light diode to control current in proportion to reference current through light diode; the feedback test end provides feedback signals for one current adjust characteristic voltage.

Description

technical field [0001] The invention relates to a charge pump driving circuit, in particular to a charge pump driving circuit for light emitting diodes. Background technique [0002] FIG. 1( a ) shows a detailed circuit diagram of a known charge pump driving circuit 10 . The charge pump driving circuit 10 converts an input voltage source V in becomes a driving voltage V out , for driving a load 11 . Many times the input voltage source V in may not be suitable for direct use to drive a load11, such as an input voltage source V in When situations such as too high, too low, or too large a disturbance occur, it is necessary to use the charge pump drive circuit 10 to adjust an appropriate and stable drive voltage V out . For example, the known charge pump driving circuit 10 shown in FIG. phase and a discharge phase, resulting in a drive voltage V out equal to the input voltage source V in twice as much. [0003] Specifically, the 2x charge pump 12 shown in FIG. 1( a ) i...

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Problems solved by technology

[0005] Although the known charge pump driving circuit 10 shown in FIG. 1(a) can provide a stably regulated driving voltage V out to the load 11, but in the case of the load 11 belonging to a light emitting diode (LED), the known charge pump drive circuit 10 cannot effectively control the brightness of the light emitting diode, because the brightness of the light emitting diode is determined by the driving current rather than the driving voltage

Moreover, in order to ensure that the LED is turned on, the known charge pump driving circuit 10 usually provides an unnecessarily large driving voltage V out , resulting in the inability to achieve the best driving efficiency

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