| 摘要 |
An operating circuit applied to a backlight is provided, where the backlight includes a plurality of lighting elements, and the operating circuit includes a plurality of current control circuits, a plurality of switches, a minimum voltage selector, a supply voltage generating circuit and a control unit. The current control circuits are coupled to the lighting elements via a plurality of nodes, respectively. The switches are coupled to the nodes, respectively. The minimum voltage selector is utilized for receiving at least a portion of voltages of the plurality of nodes, and selecting a minimum voltage among the received voltages. The supply voltage generating circuit is utilized for generating a supply voltage of the lighting elements according to the minimum voltage. For each of the switches, the control unit determines an on/off state of the switch by determining whether the corresponding lighting element is an open circuit or not. |
| 主权项 |
1. An operating circuit applied to a backlight, wherein the backlight comprises a plurality of lighting elements, each of the lighting elements comprises at least one lighting unit, and the operating circuit comprises:
a plurality of current control circuits, coupled to the plurality of lighting elements via a plurality of nodes, respectively; a plurality of switches, coupled to the plurality of nodes, respectively; a minimum voltage selector, coupled to the plurality of switches, for receiving at least a portion of voltages of the plurality of nodes, and selecting a minimum voltage among the received voltages; a supply voltage generating circuit, coupled to the minimum voltage selector, for generating a supply voltage of the plurality of lighting elements according to the minimum voltage; and a control unit, coupled to the plurality of switches and the supply voltage generating circuit, wherein for each of the switches, the control unit determines an on/off state of the switch by determining whether the corresponding lighting element is an open circuit or not; wherein the control circuit comprises:
a plurality of second comparators, for generating a plurality of switch control signals by comparing the voltages of the plurality of nodes with a second reference voltage, respectively; anda first comparator, for determining whether to enable the plurality of second comparators or not by detecting if the supply voltage is greater than a first reference voltage, wherein when the supply voltage is greater than the first reference voltage, the second comparators are enabled; and when the supply voltage is not greater than the first reference voltage, the second comparators are disabled;wherein the plurality of switch control signals are utilized for switching on or switching off the plurality of switches, respectively. |
