LED2472GBTR

LED2472G 24-channels LED driver with error detection and gain control Datasheet - production data Description 74)3(3 0/34(3[ Features • 24 constant current output channels • Output current: from 4 mA to 72 mA • 8 x 3 independently controlled channels (RGB) • Current programmable through external resistor • 7-bit global current gain adjustment in two ranges • Error detection mode (both open and shorted LED) • Programmable shorted LED detection thresholds • Auto power-saving / auto wakeup • Gradual output delay (selectable) The LED2472G is a monolithic, low voltage, low current power 24-bit shift register designed for LED panel displays with particular features oriented to indoor and outdoor LED screen billboards. The LED2472G guarantees 20 V of output driving capability, allowing several LEDs to be connected in series. The device is configured in 3 groups (red, green and blue) of 8 independently-controlled channels. The LED current can be separately regulated for each color within the range from 4 mA to 72 mA. This range is divided into two sub-ranges and the current can be adjusted within each range in 64 steps of resolution (6 bits per color). A single external resistor is required. All the controls and the shift register data are accessible via serial interface. A single 24-bit configuration register is used to choose features and settings to fit the application. The LED failure detection circuit checks 3 different conditions that can occur at the output line: short to GND, short to LED power supply rail or open channel. The auto power shutdown and auto power-on feature (selectable) allows the device to save power without any external intervention. Thermal management includes overtemperature flag and the output thermal shutdown (170 °C). The high clock frequency of up to 30 MHz makes the device suitable for high data rate transmission. A selectable gradual output delay reduces the inrush current. The supply voltage ranges from 3 V and 5.5 V. • Supply voltage: 3 V to 5.5 V • Thermal shutdown and thermal flag Table 1. Device summary • Up to 30 MHz CLK 4 wires interface • 20 V current generators rated voltage Applications Order code Package LED2472GBTR TQFP48-EP LED2472GQTR MLPQ40-EP 5x5 Packaging Tape and reel • Full color large displays • LED signage • LED screens for indoor and outdoor billboards July 2021 This is information on a product in full production. DocID024620 Rev 5 1/39 www.st.com 39 Contents LED2472G Contents 1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3 Thermal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5 Switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 6 Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7 Simplified Internal block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.1 8 Equivalent circuits of inputs and outputs . . . . . . . . . . . . . . . . . . . . . . . . . 17 Digital blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8.1 Register access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 8.2 Configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8.3 Current ranges (CFG 0-CFG 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 8.4 Error detection conditions (CFG 3-CFG 5) . . . . . . . . . . . . . . . . . . . . . . . . 21 8.5 Auto power shutdown / wakeup (CFG 6) . . . . . . . . . . . . . . . . . . . . . . . . . 21 8.6 SDO delay (CFG 7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.7 Gradual output delay (CFG 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.8 Data flow management (CFG 9-CFG 11) . . . . . . . . . . . . . . . . . . . . . . . . . 23 8.9 Gain register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 9 Current adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 10 LED error detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 11 Thermal shutdown and thermal alert . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2/39 DocID024620 Rev 5 LED2472G Contents 12 Dropout voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 13 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 DocID024620 Rev 5 3/39 List of tables LED2472G List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. Table 14. Table 15. Table 16. Table 17. 4/39 Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Thermal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Switching characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Digital keys summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Diagnostic thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Gradual output delay values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Gain register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Current adjustment example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Thermal alert status summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Minimum dropout voltage for some current values (only one channel ON) . . . . . . . . . . . . 31 TQFP48-EP mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 MLPQ40-EP 5x5 mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 DocID024620 Rev 5 LED2472G List of figures List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Pinout for TQFP48EP (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pinout for MLPQ40 (top view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Timing for clock, serial-in, serial-out, latch enable and outputs . . . . . . . . . . . . . . . . . . . . . 15 OE and Outputs timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 LED2472G simplified block diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Input terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Data input time diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Digital key timing diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 SDO Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Gradual delay on first four channels of RED color group . . . . . . . . . . . . . . . . . . . . . . . . . 23 Different color sequence in data loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Iout vs. gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 External resistor to connect to ISET pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Error detection process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 LE high for 14 CLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Typical dropout voltage vs. output current (only one channel ON) . . . . . . . . . . . . . . . . . . . 31 TQFP48-EP package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 TQFP48-EP recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 MLPQ40-EP 5x5 package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 MLPQ40-EP 5x5 recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 DocID024620 Rev 5 5/39 Pin description 1 LED2472G Pin description 5 * % 5 * % 5 * % 5 * % Figure 1. Pinout for TQFP48EP (top view)             1&   1& 6',   6'2 /(   52( &/.   *2( 1&   %2( 1&   9'' 1&   *1' 74)3H[SRVHGSDG 1&  1&            % 1&   * 1&  5 ,6(7  % 1&  * 1&  5  %  * 5(6(59(' 5 *1' %  *  5 5(6(59(' $09 5  * 5 % * 5 % * 5 % * Figure 2. Pinout for MLPQ40 (top view)    % 6', 6'2 /( 52( 1& *2( 1& %2( 0/34/[ 1& 9'' *1' &/. 5(6(59(' *1' 5(6(59(' ,6(7   5 % * 5 % * 5 % % *   * 5 $09 6/39 DocID024620 Rev 5 LED2472G Pin description Table 2. Pin description Pin Symbol Name and function 23, 24 GND Ground 2 2 SDI serial data input 3 3 LE Latch enable 8,9 8, 9 Reserved Not used in applications 4 7 CLK Clock 1, 5, 6, 7, 10, 11, 12, 25, 26, 28, 36 4, 5, 6 NC Not connected 31 25 VDD Power supply voltage 13 10 R1 Red output 1 14 11 G1 Green output 1 15 12 B1 Blue output 1 16 13 R2 Red output 2 17 14 G2 Green output 2 18 15 B2 Blue output 2 19 16 R3 Red output 3 20 17 G3 Green output 3 21 18 B3 Blue output 3 22 19 R4 Red output 4 23 20 G4 Green output 4 24 21 B4 Blue output 4 27 22 ISET Current setup 32 26 BOE Blue output enable 33 27 GOE Green output enable 34 28 ROE Red output enable 35 29 SDO Serial data output 37 30 B5 Blue output 5 38 31 G5 Green output 5 39 32 R5 Red output 5 40 33 B6 Blue output 6 41 34 G6 Green output 6 42 35 R6 Red output 6 43 36 B7 Blue output 7 44 37 G7 Green output 7 45 38 R7 Red output 7 46 39 B8 Blue output 8 TQFP48 MLPQ40 29, 30 DocID024620 Rev 5 7/39 Pin description LED2472G Table 2. Pin description (continued) Pin 8/39 Symbol Name and function 40 G8 Green output 8 1 R8 Red output 8 TQFP48 MLPQ40 47 48 DocID024620 Rev 5 LED2472G 2 Absolute maximum ratings Absolute maximum ratings Stressing the device above the ratings listed in the Table 3 may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 3. Absolute maximum ratings Symbol VDD VI OUT Io IGND ESD Parameter Value Unit -0.4 to 7 V -0.4 to Vdd+0.4 V Driver outputs voltage (R, G, B) 20 V Output current 80 mA GND terminal current 1.9 A Electrostatic discharge protection HBM human body model ±2 KV ±200 V Supply voltage Digital inputs voltage Electrostatic discharge protection MM machine model DocID024620 Rev 5 9/39 Thermal characteristics 3 LED2472G Thermal characteristics Table 4. Thermal characteristics Symbol Ta TJ-OPR Tstg Parameter Operative free-air temperature range (1) Value -40 to +85 Operative thermal junction temperature range -40 to +125 Storage temperature range -55 to +150 Junction-ambient thermal resistance; QFN40-EP(2) Unit °C 25.3 °C/W 33 °C/W Rthja Junction-ambient thermal resistance; TSSOP48-EP(1) 1. This data must be considered in adequate power dissipation conditions. The junction temperature must be maintained below 150 °C. 2. In accordance with JEDEC standard 51-7B. The exposed pad should be soldered directly to the PCB to obtain the thermal benefits. 10/39 DocID024620 Rev 5 LED2472G 4 Electrical characteristics Electrical characteristics Vdd = 3.3 V, Tj = 25 °C, GRG = “1” (gain reg), Rext = 13 kΩ, unless otherwise specified. Table 5. Electrical characteristics Symbol Parameter Vdd Supply voltage VOUT Output voltage VIH VIL VOL Test conditions Min. Typ. 3 For all outputs Input voltage Max. Unit 5.5 - - 19 0.7•Vdd - Vdd GND - 0.3•Vdd V Serial data output voltage (SDO) VDD = 3 to 5.5 V I = +/- 1 mA - - 0.4 VDD-0.4 - - IOleak Output leakage current Vo = 19 V, all outputs OFF - - 0.5 uA Vuvlo1 UVLO threshold voltage (rising) 2.7 2.9 V Vuvlo1 UVLO threshold voltage (falling) Hyuvlo UVLO hysteresis VOH 2.2 2.3 V 400 mV Vo = 0.3 V; (Io=5 mA) CFG-0 = CFG-1 = CFG-2 = “0” GRG = “0” - - ±4 Vo = 0.6 V; (Io = 21 mA) CFG-0 = CFG-1 = CFG-2 = “0” - - ±3 Vo = 0.5 V; (Io=15 mA) CFG-0 = CFG-1 = CFG-2 = “1” GRG = “0” - - ±3 ∆IOL4 Vo = 1.2 V; (Io=61 mA) CFG-0 = CFG-1 = CFG-2 = “1” - - ±3 ∆IOL1a Vo = 0.3 V; (Io = 5 mA) CFG-0 = CFG-1 = CFG-2 = “0” GRG = “0” - - ±6 - - ±6 - - ±6 - - ±6 ∆IOL1 ∆IOL3 ∆IOL2 ∆IOL3a ∆IOL2a ∆IOL4a Output current precision channel-to-channel per each color group (all outputs ON)(1)(2) Vo = 0.6 V; (Io=21 mA) Output current error device-toCFG-0 = CFG-1 = CFG-2 = “0” device per each color group Vo = 0.5 V; (Io = 15 mA) (all outputs ON)(1) CFG-0 = CFG-1 = CFG-2 = “1” GRG = “0” Vo = 1.2 V; (Io = 61 mA) CFG-0 = CFG-1 = CFG-2 = “1” DocID024620 Rev 5 % 11/39 Electrical characteristics LED2472G Table 5. Electrical characteristics (continued) Symbol Parameter Test conditions Min. Typ. Max. %/∆VOUT Output current vs. output voltage regulation(3) Vo from 1.2 V to 3 V; (Io = 61 mA) CFG-0 = CFG-1 = CFG-2 = “1” - ±0.2 - %/∆VDD Output current vs. supply voltage regulation(4) Vdd from 3 V to 5.5 V Vo = 1.2 V; (Io = 61 mA) CFG-0 = CFG-1 = CFG-2 = “1” - ±1 - Rup Pull-up resistor for OE pin Rdw Pull-down resistor for LE pin 400 500 650 Rext External current setup resistance %/V kΩ 100 No data transfers, all outputs OFF, CFG-0 = CFG-1 = CFG-2 = “0” GRG = “0”; CFG-6 = “0” 8 IDD2 No data transfers, all outputs OFF, CFG-0 = CFG-1 = CFG-2 = “1” CFG-6 = “0” 16 IDD1 No data transfers, all outputs ON, CFG-0 = CFG-1 = CFG-2 = “0” GRG = “0” - No data transfers, all outputs ON, CFG-0 = CFG-1 = CFG-2 = “1” - All output OFF CFG-6 = “1” - IDD1 Supply current (OFF) Supply current (ON) IDD2 IDD (AutoOFF) SDE1 SDE2 Supply current (autoOFF) LED short detection voltage mA 8 mA 15 200 CFG-3 = CFG-4 = CFG-5 = “0” 2.0 CFG-3 = CFG-4 = CFG-5 = “1” 3.0 ODC LED open detection current 0.5 IOL Tflg Thermal flag 150 Tsd Tsd-hy Thermal shutdown (5) Thermal shutdown hysteresis(5) 15 2. ((Ioutn - Ioutavg1-15)/ Ioutavg1-15) x 100 3. ( Ioutn @ Voutn = 3. 0 V ) − (Ioutn @ Voutn = 1 .0 V ) 100 × ( Ioutn @ Voutn = 1 .0 V ) 3 −1 4. ∆ (% / V) = (Ioutn @ Vdd = 5. 5V) − (Ioutn @ Vdd = 3.0V ) 100 × (Ioutn @ Vdd = 3. 0V) 5. 5 − 3 5. Not tested, guaranteed by design. 12/39 500 DocID024620 Rev 5 µA V 170 1. Tested with just one output loaded ∆ (% / V ) = Unit °C 20 LED2472G 4.1 Electrical characteristics Typical application circuit Figure 3. Typical application circuit DocID024620 Rev 5 13/39 Switching characteristics 5 LED2472G Switching characteristics Vdd = 3.3 V, Tj = 25 °C, GRG = “1” (gain reg), Rext = 13 kΩ, unless otherwise specified. Table 6. Switching characteristics(1)(2) Symbol Parameter Conditions Min. Typ. Max. Unit fclk Clock frequency Cascade operation - - 30 MHz tr(SDO) SDO rise time - 5 - tf(SDO) SDO fall time - 5 - - 70 - - 100 - 8 15 25 - 70 - - 100 - 15 25 - - - - - - tPLH2 LE-OUTn(3) tPLH3 OE-OUTn(3) tPLH CLK-SDO CFG-7 = ‘0’ tPHL2 LE-OUTn(3) tPHL3 OE-OUTn(3) tPHL CLK-SDO CFG-7= ‘0’ tw(CLK) CLK tW(OE) OE tw(L) LE tgr-d Gradual delay Ch to Ch tsu(L) Setup time for LE 5 - - th(L) Hold time for LE 5 - - tsu(D) Setup time for SDI 5 - - th(D) Hold time for SDI 10 - - tor(5) Maximum CLK rise time - - 5 (5) Maximum CLK fall time - - 5 - - 10 % - - 1 µs tof Propagation delay time (“L” to “H”) Propagation delay time (“H” to “L”) Pulse width Rext = 13 kΩ; Iout = 21 mA 8 Vout = 0.6 V VIH = VDD; VIL = GND 20 RL = 56 Ω; CL = 10 pF 150(4) CFG-0 = CFG-1 = CFG-2 = “0” 20 ns 10 Vout = 0.3 to 3 V CL = 10 pF; Iout = 5 to 61 mA µs Iout-ov Output current turn-on overshoot tn-err Normal error detection minimum output ON time tshut-down Auto power shutdown time (autoOFF) From LE falling edge to Rext voltage reference at -10% - 75 - ns twake-up Auto power wakeup time From LE falling edge to Rext voltage reference at 90% - 1 - µs 1. All table limits are guaranteed by design. 2. Not tested in production. 3. CFG-8 = “1” (no output gradual delay) 4. In normal error detection mode must be longer than 1 µs 5. If devices are connected in cascade and tor or tof is large, it may be critical to achieve the timing required for data transfer between two cascaded devices. 14/39 DocID024620 Rev 5 LED2472G 6 Timing Timing Figure 4. Timing for clock, serial-in, serial-out, latch enable and outputs AM13690V1 Correct sampling of the data depends on the stability of the data at SDI on the rising edge of the clock signal and it is assured by a proper data setup and hold time (tSU(D) and th(D)), as shown in Figure 4. The same figure shows the propagation delay from CLK to SDO (tPLH/tPHL). Figure 4 describes also the minimum duration of CLK and LE pulses (tW(CLK) and tW(L), respectively) and the propagation delay from LE to OUTn (tPLH1/tPHL1 and tPLH2/tPHL2, respectively). Finally, Figure 5 also defines the turn-on and turn-off time (tof and tor) of the output voltage. Figure 5. OE and Outputs timing $09 DocID024620 Rev 5 15/39 Simplified Internal block diagram 7 LED2472G Simplified Internal block diagram Figure 6. LED2472G simplified block diagram 16/39 DocID024620 Rev 5 LED2472G 7.1 Simplified Internal block diagram Equivalent circuits of inputs and outputs Input terminals LE and /OE have pull-down and pull-up connections, respectively. CLK and SDI must be connected to external circuits to fix the logic level. Figure 7. Input terminals OE terminal CLK, SDI terminal LE terminal SDO terminal AM13692V1 DocID024620 Rev 5 17/39 Digital blocks 8 LED2472G Digital blocks The data inputs come in through the serial interface at each CLK rising edge and after 24 CLK cycles all data are loaded into the shift register. The LE signal is used to latch the loaded data and also to generate digital keys for CFG management, scrolling, thermal check and LED error detection. When one of the output enable signal (OER, OEB or OEG) is low, the corresponding data are transferred to the relative output drivers. The data flow is “first in, first out”. To latch the data, the LE signal must be high during the last data loading CLK rising edge (Table 7). When one of the output enable signals (OER, OEB or OEG) is at low level, output terminals (R1-R8,G1-G8, B1-B8) respond to the data either ON or OFF. When one of the output enable signals (OER, OEB or OEG) goes to “1”, all outputs switch off all the data on the output terminal. LE and /OE signals are asynchronous with respect to the CLK signal. The time diagram below refers to RGB flow setting. Figure 8. Data input time diagram                         6', &/. /( 2( 5*% 5 2)) 21 5 2)) 21 * 2)) 21 * 2)) 21 * 2)) 21 % 2)) 21 % 2)) 21 ELWGDWD $09 8.1 Register access Access to the different registers of the device (configuration register, gain register, etc.) is achieved by using different digital keys, defined as a number of CLK pulses during which the LE signal is asserted. The available digital keys are summarized in Table 7. 18/39 DocID024620 Rev 5 LED2472G Digital blocks Table 7. Digital keys summary #CLK rising edges with the LE asserted Description 1-2 Data latch 3-4 Write configuration register 5-6 Read configuration register 7-8 Write gain 9-10 Read gain 11 Open detection 12 Short detection 13 Open/short detection 14 Thermal alert reading 15 Reserved 16 Reserved Figure 9. Digital key timing diagram DocID024620 Rev 5 19/39 Digital blocks 8.2 LED2472G Configuration register The configuration register is used to enable or disable some device features, to program some parameters and to change other settings. Access to this register (read or write) is managed as described in Table 8 where a description is provided for each bit. The default value of the configuration register (when the device is switched ON or after a reset) is all bits set to “0”. To change anything in the configuration register, a 24-bit digital word must be sent (CFG-0 represents the LSB, CFG-23 the MSB). Figure 10. Configuration register 6',                         &/. /( ELWGDWD $09 Table 8. Configuration register 20/39 BIT Definition Attribute read/write CFG-0 RED current range R/W ”0” low current range “1” high current range 0 CFG-1 GREEN current range R/W ”0” low current range “1” high current range 0 CFG-2 BLUE current range R/W ”0” low current range “1” high current range 0 CFG-3 RED voltage det. thr. R/W “0” LED short-circuit detection threshold 2 V “1” LED short-circuit detection threshold 3 V 0 CFG-4 GREEN voltage det. thr. R/W “0” LED short-circuit detection threshold 2 V “1”LE D short-circuit detection threshold 3 V 0 CFG-5 BLUE voltage det. thr. R/W “0” LED short-circuit detection threshold 2 V “1” LED short-circuit detection threshold 3 V 0 CFG-6 Auto OFF R/W “0” device always ON ”1” auto power shutdown active (Auto OFF) 0 CFG-7 SDO delay R/W “0” SDO half clock delay disabled “1” SDO half clock delay enabled 0 CFG-8 Gradual output delay R/W “0” gradual outputs delay is applied ”1” all channels switch ON and OFF simultaneously 0 Configuration register function description DocID024620 Rev 5 Default LED2472G Digital blocks Table 8. Configuration register (continued) BIT Attribute read/write Definition Configuration register function description Default CFG9 CFG10 CFG11 CFG-9 CFG-10 Data flow R/W Color data flow management CFG-11 CFG 12 ÷ 23 8.3 0 0 0 RGB 0 0 1 GBR 0 1 0 GRB 0 1 1 BGR 1 0 0 BRG 1 0 1 RBG 0 0 0 Don’t care Current ranges (CFG 0-CFG 2) The output LED currents can be programmed using an external resistor connected to GND from the ISET pin and can be adjusted using 6 bits in a dedicated gain register with two possible current ranges selectable in the configuration register. Each range can be separately selected for each color by the bits CFG-0, CFG-1 and CFG-2, respectively, for the RED, GREEN and BLUE channels. 8.4 Error detection conditions (CFG 3-CFG 5) During error detection phases for each channel, the following are checked: – output current for open circuit detection – output voltage for short-circuit detection The thresholds for the error diagnostics are summarized in the Table 9: Table 9. Diagnostic thresholds Error detection Checked malfunction CFG-x(1) Thresholds Open detection combined mode Open line or output short to GND Don’t care Io < 0.5 x Io_programmed Short detection Short on LED or short to VLED 0 Vo > 2 V 1 Vo > 3 V 1. x=3 for RED, x=4 for GREEN, x=5 for BLUE 8.5 Auto power shutdown / wakeup (CFG 6) This feature reduces the power consumption when all outputs are OFF. It is active when the bit CFG-6 of the configuration register is at “1”. The auto power shutdown (auto OFF) starts when the data latched is “0” for all channels, and the device will be active again (wakeup) at the first latched data string including at least one bit equal to “1” (at least one channel ON). DocID024620 Rev 5 21/39 Digital blocks LED2472G Timings for shutdown and wakeup are present in the dynamic features table. While the auto power shutdown is active, the device ignores any other command except channel power-on. 8.6 SDO delay (CFG 7) Normally, on SDO terminals data is shifted out at the rising edge of the CLK signal with a propagation delay of about 15 ns [signal (1) in Figure 11]. The device provides the possibility to shift data out also at the falling edge of the CLK signal with a propagation delay of few ns [signal (2) in Figure 11]. This feature can be activated by setting to “1” the bit CFG-7 of the configuration register. The default setting for this bit is “0”, hence the SDO delay is not activated by default. This feature is particularly useful when multiple devices are connected in daisy chain configuration with non-matched delays between the CLK and SDO data paths (board routing). Figure 11. SDO Delay 8.7 Gradual output delay (CFG 8) The gradual output delay consists in turning on gradually the current generators, avoiding turning on all channels at the same time. This feature prevents large inrush current and reduces the bypass capacitor values. The fixed delay time can be activated by bit CFG-8 of the configuration register, and the typical delay is 10 ns for each group of 8 outputs R, G, B (e.g. R1, G1, B1 has no delay, R2, G2, B2 has 10 ns of delay and R3, G3, B3, has 20 ns delay, and so on), as described in Table 10. 22/39 DocID024620 Rev 5 LED2472G Digital blocks Table 10. Gradual output delay values R1 R2 R3 R4 R5 R6 R7 R8 G1 G2 G3 G4 G5 G6 G7 G8 B1 B2 B3 B4 B5 B6 B7 B8 CFG-8 = “0” 0 10 20 30 40 50 60 70 CFG-8 = “1” 0 0 0 0 0 0 0 0 Delay time (ns) from the falling edge of xOE Figure 12 shows an example of the effect of the output gradual delay on the RED color group outputs. Figure 12. Gradual delay on first four channels of RED color group 8.8 Data flow management (CFG 9-CFG 11) The 8x3 shift registers have a default RGB sequence serial data flow according to the table shown into the configuration register (bit CFG-9, CFG-10 and CFG-11). Figure 13 shows how serial data are loaded in accordance with the data flow sequence selected through the configuration register. The default sequence is RGB (first bit will be R8, last bit B1 then: R8R1, G8-G1, B8-B1). DocID024620 Rev 5 23/39 Digital blocks LED2472G Figure 13. Different color sequence in data loading JURXS JURXS JURXS &)*    06%ILUVWELW 5*%    5 5 * * % % *%5    * * % % 5 5 *5%    * * 5 5 % % %*5    % % * * 5 5 %5*    % % 5 5 * * 5%*    5 5 % % * * ELWVGDWDVWUHDP  /6%ODVWELW $09 8.9 Gain register The LED current can be programmed using an external resistor connected to GND from REXT pin and can be adjusted using the dedicated bits of the gain register (G-0 to G-17 defines the gain and CFG-0/1/2 the current range within the gain can be adjusted). The device can regulate the current up to 72 mA and down to 4 mA. To change anything in the gain register, a 24-bit digital word must be sent (CFG-0 represents the LSB, CFG-23 the MSB). The accuracy of the LED current depends on the selected range and it is assured only in the ranges indicated in the static electrical characteristics (see Table 5). Table 11. Gain register BIT Definition Attribute read/write Register function description G-0 1 G-1 G-2 G-3 RED current gain adjustment R/W G-4 6-bit DAC allows adjustment of the device output current in 64 steps for each range (defined by CFG-0). default: gain = 1 1 1 1 1 G-5 1 G-6 1 G-7 G-8 G-9 G-10 GREEN current gain adjustment R/W 6-bit DAC allows adjustment of the device output current in 64 steps for each range (defined by CFG-1). default: gain = 1 G-11 24/39 Default 1 1 1 1 1 DocID024620 Rev 5 LED2472G Digital blocks Table 11. Gain register (continued) BIT Attribute read/write Definition Register function description Default G-12 1 G-13 G-14 G-15 BLUE current gain adjustment R/W G-16 1 6-bit DAC allows adjustment of the device output current in 64 steps for each range (defined by CFG-2). default: gain = 1 1 1 1 G-17 1 G-18 to G-23 Don’t care Figure 14. Iout vs. gain 5 UDQJHVHOHFWLRQ5H[W .RU. ϳϬ͘Ϭ ϭϯ