| 摘要 |
A multi-LED string driving circuit and an LCD backlight unit using the same are provided to detect the abnormality of an LED string unit, cut off the operation of the LED string unit in a converter unit when the abnormality of the LED string unit occurs, and hold the operation cut-off state until the abnormality of the LED string unit is solved or power is reapplied. A plurality of LED(Light Emitting Diode) strings(110b) are connected in parallel in an LED string unit(100b). Plural LEDs(111b) are connected in series in the plurality of LED strings. A converter unit(200) supplies a driving voltage to the LED string unit. An open detecting circuit unit(400b) detects the abnormality of the LED string unit. A protection circuit unit(500b) determines the abnormality of the LED string unit by the abnormality detection of the open detecting circuit unit. A control unit(600) controls the converter unit to cut off the driving voltage supplied to the LED string unit when the abnormality of the LED string unit is determined by the protection circuit unit. The open detecting unit includes an AND circuit(410b) which detects abnormality when at least one LED string in the plurality of LED string is open. |
