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## TLC5957 Datasheet(PDF) 14 Page - Texas Instruments

 Part No. TLC5957 Description TLC5957 48-Channel, 16-Bit ES-PWM LED Driver with Pre-Charge FET, LED OPEN Detection and Caterpillar Cancelling Download 25 Pages Scroll/Zoom 100% Maker TI1 [Texas Instruments] Homepage http://www.ti.com Logo

## TLC5957 Datasheet(HTML) 14 Page - Texas Instruments

 14 / 25 page TLC5957SLVSCQ4 – OCTOBER 2014www.ti.comDevice Functional Modes (continued)Table 1. CC Data vs Current Ratio and Set Current ValueRATIO OF OUTPUTCC DATA (CCR or CCG or CCB)CURRENTOUTPUT CURRENT (mA, RIREF = 7.41 kΩ)TO IolcMax(%, typical)BC = 7hBC = 0hBINARYDECIMALHEX(IolcMax =25mA)(IolcMax=3.2mA)0 0000 00000000000 0000 00011010.20.050.0060 0000 00102020.40.100.013——————1 0000 000025610050.112.521.621(Default)(Default)(Default)——————1 1111 11015091FD99.624.903.2221 1111 11105101FE99.824.953.2291 1111 11115111FF100.0253.2359.3.3 Select RIREF For a Given BCThe maximum output current per channel, IOLCMax is determined by resistor RIREF placed between the IREF andIREFGND pins, and the BC code in FC register. The voltage on IREF is typically 1.209V. RIREF can be calculatedby Equation 2.Riref(kΩ) = Viref(V) / IOLCMax(mA) × Gain(2)Where:VIREF = the internal reference voltage on IREF (1.209V, typical)IOLCMax is the largest current for each output at CCR/G/B=1FFh.Gain = the current gain at a selected BC code (See Table 2 )Table 2. Current Gain Versus BC CodeBC DATARATIO OFGAINGAIN / GAIN_MAX (AT MAX BC)BINARYHEX000 (recommend)0 (recommend)20.012.9%001139.525.6%010258.637.9%011380.952.4%100 (default)4 (default)100.064.7%1015113.373.3%1106141.691.7%1117154.5100%NOTE: Recommend to use smaller BC code for better performance. For noise immunity purposes, suggest RIREF < 60 kΩ.9.3.4 Choosing BC/CC For a Different ApplicationBC is mainly used for global brightness adjustment between day and night. Suggested BC is 4h, which is in themiddle of the range; thus, one can change brightness up and down flexibly.CC can be used to fine tune the brightness in 512 steps, this is suitable for white balance adjustment betweenRGB color groups. To get a pure white color, the general requirement for the luminous intensity ratio of R, G, BLED is 3:6:1. Depending on LED’s characteristics (Electro-Optical conversion efficiency), the current ratio of R,G, B LED will be much different from this ratio. Usually, the Red LED will need the largest current. One canchoose 511d(the max value) CC code for the color group which needs the largest current at first, then chooseproper CC code for the other two color groups according to the current ratio requirement of the LED used.14Submit Documentation FeedbackCopyright © 2014, Texas Instruments Incorporated