Abstract: A high-voltage high-power constant current LED driver device, can drive LED cluster, comprises switch tube, current sensing resistor Rcs and inductor L, particularly, comprises a low voltage control circuit that detects the voltage drop on the said current sensing resistor Rcs to produce a control signal transmitting to the control terminal of the switch tube; the said current sensing resistor Rcs connects with inductor L in series and is positioned between the output terminal of switch tube and the current output terminal of the current driving device in series connection; the input terminal of the said switch tube is connected to a DC voltage source; and also comprises a diode D3 which the cathode is connected to the output terminal of the said switch tube and anti cathode is grounding. The device of the invention has the advantages of constant current, simple driving circuit and low cost under the high-voltage high-power application.

Abstract: A high-voltage high-power constant current LED driver device, can drive LED cluster, comprises switch tube, current sensing resistor Rcs and inductor L, particularly, comprises a low voltage control circuit that detects the voltage drop on the said current sensing resistor Rcs to produce a control signal transmitting to the control terminal of the switch tube; the said current sensing resistor Rcs connects with inductor L in series and is positioned between the output terminal of switch tube and the current output terminal of the current driving device in series connection; the input terminal of the said switch tube is connected to a DC voltage source; and also comprises a diode D3 which the cathode is connected to the output terminal of the said switch tube and anti cathode is grounding. The device of the invention has the advantages of constant current, simple driving circuit and low cost under the high-voltage high-power application.

Abstract: A current mode digital-to-analog converter (DAC) consisting of a bias generator, a current mode scale-down section and a current mode scale-up section is presented which converts an n-bit digital input into an analog output. The bias generator ensures a constant reference current is caused to flow into both scale-down and scale-up sections of the DAC. The scale-down section uses the m lower-order bits of the n-bit digital input to generate a combined fractional current based on the reference current. The (n-m) higher-order bits of the n-bit digital input are used by the scale-up section to generate a multi-unit current based on the reference current. The fractional and multi-unit currents are simultaneously added together onto the output node to generate the desired analog output.