Invention Grant
US08203506B2 LED drive circuit 有权
LED驱动电路

LED drive circuit
Abstract:
An LED array includes a plurality of LED segments connected in a common cathode configuration at a common cathode node. A high side driver is operable responsive to segment control signals to selectively supply current to certain LED segments. A low side driver is provided to sink current from the common cathode node. A plurality of selectively actuated current sink paths are provided in each low side driver. A control logic circuit actuates a current sink path within the low side driver for each LED segment that is selectively supplied current by the high side driver. A substantially constant low side voltage drop through these sink paths is provided regardless of the number of LED segments that are supplied current by the high side driver so as to achieve a substantially constant LED segment brightness. A common anode configuration operating in an analogous way is also disclosed.
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