| 摘要 |
PROBLEM TO BE SOLVED: To provide electronic circuits and methods for driving light emitting diode strings without requiring a minimum select circuit to select a minimum voltage appearing at an end of one of a plurality of series-connected LED strings.SOLUTION: A method of driving a plurality of series-connected light emitting diode strings 14, 16, 18 with a controllable DC-DC converter 12a includes attempting to pass a corresponding predetermined current through each one of the plurality of series-connected light emitting diode strings with a corresponding feedback current control circuit, resulting in a corresponding voltage appearing at an end of each one of the plurality of series-connected light emitting diode strings. A control node of the feedback circuit generates a control voltage 162, 164, 166 that changes in a direction opposite to a change of the corresponding voltage. The method also includes detecting 168 the largest one of the control voltages, and generating an error signal 174 representative of said largest one of the control voltages to control the DC-DC converter. |
