TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 HIGH EFFICIENCY CHARGE PUMP FOR 7 WLEDs WITH I2C INTERFACE FEATURES 1 • • • • • • • • • • • • 3.0 V to 6.0 V Input Voltage Range ×1 and ×1.5 Charge Pump Fully Programmable Current with I2C – 64 Dimming Steps with 25mA Maximum (Sub and Main Display Banks) – 4 Dimming Steps with 80mA Maximum (DM5 for Auxiliary Application) 2% Current Matching for Sub LEDs at Light Load Condition (Each 100µA) 750 kHz Charge Pump Frequency Continuous 230mA Maximum Output Current Auto Switching Between ×1 and ×1.5 Mode for Maximum Efficiency Built-in Soft Start and Current Limit Open Lamp Detection 16-Pin 3mm x 3mm QFN TPS60250 (I2C Slave Address: 1110111) TPS60252 (I2C Slave Address: 1110110) DESCRIPTION The TPS60250/2 are high efficiency, constant frequency charge pump DC/DC converters that use dual mode 1× and 1.5× conversions to maximize efficiency over the input voltage range. The devices drive up to five white LEDs for the main display and up to two white LEDs for the sub display with regulated constant current for uniform intensity. By utilizing adaptive 1×/1.5× charge pump modes and very low-dropout current regulators, the TPS60250/2 achieve high efficiency over the full 1-cell lithium-battery input voltage range. Four enable inputs, ENmain, ENsub1, ENsub2, and ENaux, available through the I2C, are used for simple on/off controls for the independent main, sub1, sub2, and DM5 displays, respectively. To lower the operating current when using one sub display LED, the devices provide completely separate operation for the sub display LEDs. The TPS60250/2 are available in a 16-pin 3mm x 3mm thin QFN. APPLICATIONS • • • Main Display Cellular Phones PDA, PMP, GPS (Up To 4 Inch LCD Display) Multidisplay Handheld Devices GND DM4 DM3 DM2 C1DM1 95 4 Main LED - 15 mA, VF = 3.1 V 90 Efficiency - % 85 C2 1mF 80 C3 1mF 75 70 C2+ DS2 C2- DS1 C1+ DM5 VIN SCLK SDAT Sub Display VOUT 65 C4 4.7mF 60 C1 4.7mF 55 I2C Interface On/Off, Digital Dimming 50 3 3.5 4 4.5 5 VI - Input Voltage - V 5.5 Figure 2. Typical Application for Sub and Main 6 Figure 1. Efficiency vs Input Voltage ORDERING INFORMATION (1) PART NUMBER TPS60250RTE TPS60252RTE (1) PACKAGE TA 16-Pin 3 mm × 3 mm QFN (RTE) –40°C to +85°C For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2007–2008, Texas Instruments Incorporated TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) (1) VI Input voltage range (all pins) VALUE UNIT –0.3 to 7 V 650 mA 2 kV 500 V MAX Output current limit HBM ESD Rating (2) CDM ESD Rating (3) MM ESD Rating (4) TA Operating temperature range TJ Maximum operating junction temperature TST Storage temperature (1) (2) (3) (4) 200 V –40 to 85 °C 150 °C –55 to 150 °C Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. The Human body model (HBM) is a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin. The testing is done according JEDECs EIA/JESD22-A114. Charged Device Model Machine Model (MM) is a 200pF capacitor discharged through a 500 nH inductor with no series resistor into each pin. The testing is done according JEDECs EIA/JESD22-A115. DISSIPATION RATINGS PACKAGE THERMAL RESISTANCE, RθJC THERMAL RESISTANCE, RθJA TA ≤ 25°C POWER RATING DERATING FACTOR ABOVE TA = 25°C TA = 85°C POWER RATING QFN 3×3 RTE 74.6°C/W 48.7°C/W 2.05 W 1.13 W 0.821 W RECOMMENDED OPERATING CONDITIONS MIN NOM 3.0 MAX 6.0 UNIT VI Input voltage range V IO(max) Maximum output current 230 mA CI Input capacitor 4.7 µF CO Output capacitor 4.7 µF C1, C2 Flying capacitor TA Operating ambient temperature –40 85 °C TJ Operating junction temperature –40 125 °C µF 1.0 ELECTRICAL CHARACTERISTICS VI = 3.5 V, TA = –40°C to 85°C, typical values are at TA = 25°C (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY VOLTAGE VI Input voltage range 3.0 750 kHz Switching in 1.5× mode (IMAIN_LED = 15 mA × 4, IO = 60 mA) 6.0 V 6.7 mA IQ Operating quiescent current No switching in ×1 mode (IO = 100 µA) 68 µA ISD Shutdown current Enable Control Register has 0x00 1.3 µA VUVLO1 UVLO Threshold voltage1 (1) VI falling 2.2 2.4 2.6 V VUVLO2 UVLO Threshold voltage2 (2) VI falling 1.2 1.3 1.5 V (1) (2) 2 Shut down charge pump and power stage and keep I2C content Shut down completely and come up with all 0's after device restart Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 ELECTRICAL CHARACTERISTICS (continued) VI = 3.5 V, TA = –40°C to 85°C, typical values are at TA = 25°C (unless otherwise noted) PARAMETER Vhys TS TEST CONDITIONS MIN TYP MAX UNIT Under-voltage lockout hysterisis UVLO1 210 mV Soft start time (3) VI = 3 V, CO = 1 µF, IMAIN_LED = 15 mA × 4 0.5 ms CHARGE PUMP Vout Overvoltage limit 6.5 V Fs Switching frequency 750 kHz RO Open loop output impedance ×1 Mode, (VI –VO)/IO 1.2 ×1.5 Mode, (VI × 1.5 – VO)/IO VI = 3.0V (IO = 120 mA) 3.5 5.0 0 ±2% ±0.1% ±5% Ω CURRENT SINK ISUB_LED = 100 µA × 2, VDXX = 0.4 V Km_sub Current matching of sub LEDs at light load condition (4) Km_main LED to LED Current matching (5) IMAIN_LED = 15 mA × 4, 3.0 V ≤ VI ≤ 4.2 V Ka Current accuracy ILED = 15 mA ID_MS Maximum LED current of DM1-4 and DS1-2 Main and Sub Display Current Register = 0×01&2(111111), VDXX = 0.2 V ID_DM5 Maximum LED current of DM5 Aux Display Current Register = 0×03 (XXXX11) VDropOut LED Drop out voltage See VTH_GU 1× Mode to 1.5× mode transition threshold voltage (7) VDXX Falling, 15 mA × 4 measured on the lowest VDXX VTH_GD Input voltage hysteresis for 1.5× to 1× mode transition Measured as VI – (VO – VDXX_MIN), IMAIN_LED = 15 mA × 4 ±7% 25.5 mA 80 (6) 85 mA 80 120 mV 100 120 mV 550 mV SERIAL INTERFACE TIMING REQUIREMENTS fmax Clock frequency twH(HIGH) Pulse duration, clock high time 600 400 kHz twL(LOW) Pulse duration, clock low time 1300 tr DATA and CLK rise time 300 ns tf DATA and CLK fall time 300 ns th(STA) High time (repeated) START condition(after this period the first clock pulse is generated) 600 ns tsu(STA) Setup time for repeated START condition 600 ns th(DATA) Data input hold time 0 ns tsu(DATA) Data input setup time 100 ns tsu(STO) STOP condition setup time 600 ns t(BUF) Bus free time 1300 ns ns ns I2C COMPATIBLE INTERFACE VOLTAGE SPECIFICATION (SCLK, SDAT, VIO) VIL Low-leveI input voltage 3.0 V ≤ VI ≤ 6.0 V 0 VIH High-level input voltage 3.0 V ≤ VI ≤ 6.0 V 1.1 VOL Low-level output voltage ILOAD = 2 mA (3) (4) (5) (6) (7) 0.5 V V 0.4 V Measurement Condition: From enabling the LED driver to 90% output voltage after VI is already up. LED current matching is defined as: (ISUB_LED_WORST – IAVG_SUB) / IAVG_SUB LED to LED Current Matching is defined as: (IMAIN_LED_WORST – IAVG_MAIN) / IAVG_MAIN Dropout Voltage is defined as VDXX (WLED Cathode) to GND voltage at which current into the LED drops 10% from the LED current at VDXX = 0.2 V, WLED current = 15 mA × 4. As VI drops, VDXX eventually falls below the switchover threshold of 100mV, and TPS60250/2 switches to 1.5× mode. See the Operating Principle section for details about the mode transition thresholds. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 3 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com PIN ASSIGNMENTS QFN 16-PIN RTE 3mmX3mm (TOP VIEW) GND DM4 DM3 DM2 C1- 12 11 10 9 13 8 DM1 C2+ 14 7 DS2 C2- 6 DS1 5 DM5 15 C1+ 16 1 2 3 4 VOUT VIN SCLK SDAT TERMINAL FUNCTIONS TERMINAL I/O DESCRIPTION 1 O Connect the anodes of the sub, main, and aux display white LEDs to this pin. 2 I Supply voltage input. Connect to a 3 V to 6 V input supply source. SCLK 3 I I2C Interface SDAT 4 I/O I2C Interface DM5 5 I DS1 6 I DS2 7 I DM1 8 I DM2 9 I DM3 10 I DM4 11 I GND 12 – Ground C1– 13 – Connect to the flying capacitor C1 C2+ 14 – Connect to the flying capacitor C2 C2– 15 – Connect to the flying capacitor C2 C1+ 16 – Connect to the flying capacitor C1 NAME NO. VOUT VIN 4 Current sink inputs. Connect the cathode of the aux display or the 5th main display white LED to this pin. Current sink inputs. Connect the cathode of one of the sub display white LEDs to these pins. Current sink input. Connect the cathode of one of the main display white LEDs to these pins. Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 FUNCTIONAL BLOCK DIAGRAM C 1+ 16 VIN 2 C2- C2+ C1- 15 14 VOUT DM 4 DM 3 DM 2 DM 1 1 11 10 9 8 13 1X, 1.5X CHARGE PUMP GEAR CONTROL & OPEN LAMP DETECTION ENold I2C INTERFACE 7 DS2 6 DS1 5 DM5 12 GND ENmain Main Dimming 6 ENsub 1 ENsub 2 Sub Dimming SCLK 3 ENaux AUX Dimming SDAT 6 6 4 BIAS, TEST, & MONITORING TYPICAL CHARACTERISTICS TABLE OF GRAPHS DESCRIPTION Efficiency Output Impedance of ×1 and ×1.5 Mode Shutdown Current REF Efficiency vs Input Voltage, 4 Main LED - 15 mA, 25 mA Figure 3 Efficiency vs Input Voltage, 2 Sub LED with Light Load Condition, ×1 Mode Operation Figure 4 Switch Resistance vs Free-Air Temperature, ×1 Mode, ILED = 230 mA Figure 5 Switch Resistance vs Free-Air Temperature, ×1 Mode, ILED = 100 mA Figure 6 Switch Resistance vs Free-Air Temperature, ×1.5 Mode Charge Pump Open-Loop , ILED = 230 mA Figure 7 Switch Resistance vs Free-Air Temperature, ×1.5 Mode Charge Pump Open-Loop, ILED = 100 mA Figure 8 Shutdown Current vs Input Voltage Figure 9 Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 5 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com TYPICAL CHARACTERISTICS (continued) DESCRIPTION REF Input Current Input Current vs Supply Voltage, 4 Main LED Figure 10 DM5 with Maximum 80 mA DM5 Current vs Input Voltage, Programmed with 80 mA Figure 11 Current Accuracy WLED Current vs Input Voltage, 4 Main LED with 15 mA Figure 12 EFFICIENCY vs INPUT VOLTAGE (2 Sub LED with Light Load Condition, ×1 Mode Operation) EFFICIENCY vs INPUT VOLTAGE (4 Main LED - 15mA, 25mA) 100 90 0.5 mA, VF = 2.7 V Efficiency - % Efficiency - % 1 mA, VF = 2.8 V 80 25 mA, VF = 3.79 V 80 70 60 0.2 mA, VF = 2.6 V 40 60 15 mA, VF = 3.43 V 20 50 3 4 5 3 6 4 5 VI - Input Voltage - V VI - Input Voltage - V Figure 3. Figure 4. SWITCH RESISTANCE vs FREE-AIR TEMPERATURE (×1 Mode) SWITCH RESISTANCE vs FREE-AIR TEMPERATURE (×1 Mode) 6 1.15 1.10 1.10 ILED = 230 mA ILED = 100 mA VI = 3.3 V 1.05 VI = 3.3 V Switch Resistance - W Switch Resistance - W 1.05 1 VI = 3.6 V 0.95 0.90 VI = 3.9 V 0.85 1 VI = 3.6 V 0.95 0.90 0.85 0.80 VI = 3.9 V 0.80 0.75 0.75 0.70 0.70 -40 -20 0 20 40 60 80 0.65 -40 -20 TA - Free-Air Temperature - °C Figure 5. 6 Submit Documentation Feedback 0 20 40 TA - Free-Air Temperature - °C 60 80 Figure 6. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 SWITCH RESISTANCE vs FREE-AIR TEMPERATURE (×1.5 Mode Charge Pump Open-Loop) SWITCH RESISTANCE vs FREE-AIR TEMPERATURE (×1.5 Mode Charge Pump Open-Loop) 3.8 3.8 ILED = 230 mA ILED = 100 mA 3.6 Switch Resistance - W Switch Resistance - W 3.6 VI = 3 V 3.4 3.2 3 3.4 VI = 3 V 3.2 3 2.8 2.8 -40 -20 40 20 0 TA - Free-Air Temperature - °C 60 2.6 -40 80 0 20 40 Figure 7. Figure 8. SHUTDOWN CURRENT vs INPUT VOLTAGE INPUT CURRENT vs SUPPLY VOLTAGE (4 Main LED) ICC - Input Current - A 8 6 4 TA = 85°C 0.16 0.15 0.14 0.13 0.12 80 25 mA 0.11 0.10 0.09 0.08 0.07 0.06 15 mA 0.05 0.04 0.03 0.02 TA = 25°C TA = -40°C 60 TA - Free-Air Temperature - °C 10 Shutdown Current - mA -20 2 2 mA 0.01 0 3 6 5 4 3 VI - Input Voltage - V Figure 9. 5 4 6 VI - Input Voltage - V Figure 10. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 7 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com DM5 CURRENT vs INPUT VOLTAGE (Programmed with 80 mA) WLED CURRENT vs INPUT VOLTAGE (4 Main LED with 15 mA) 0.08 0.016 IDM2 IDM3 0.07 0.06 0.35 V 0.05 IDM1 0.3 V WLED Current - A DM5 Current - A 0.4 V 0.25 V 0.2 V 0.15 V 0.1 V 0.04 0.03 0.05 V IDM4 0.014 0.012 0.02 0.01 0 2.5 0.010 3 3.5 4 3 4 VI - Input Voltage - V Figure 11. 8 Submit Documentation Feedback 5 6 VI - Input Voltage - V Figure 12. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 APPLICATION INFORMATION APPLICATION OVERVIEW Most of the current handsets fall into one of three categories. First is the clamshell design, with a main display on the inside, a secondary display on the outside and a keypad backlight. Second is the bar design, with a main display and a keypad backlight. Third is the slide type (slide-up and slide-down) design, with a main display and two keypad banks (inside and outside). The TPS60250/2 are well suited for use in these three major phone designs because the devices have 7 individually regulated white LED current paths that drive up to five white LEDs in the main display and up to two white LEDs in sub display with regulated constant current for uniform intensity. The main and sub display LED channels drive up to 25 mA and the auxiliary LED output (DM5) that drives up to 80 mA can be assigned to keypad backlight, torch light, or low cost/weak camera flash application using the I2C interface. The TPS60250/2 circuits use only 4 external components: the input/output capacitors and 2 charge pump flying capacitors. The few external components combined with the small 3mm × 3mm QFN package provide for a small total solution size. By combining independent control of three separate banks of backlight LEDs with low cost and weak flash capability, the TPS60250/2 help designers minimize power consumption especially in the case of a light load condition while reducing component count and package size. OPERATING PRINCIPLE Charge pumps are becoming increasingly attractive in battery-operated applications where board space and maximum height of the converter are critical constraints. The major advantage of a charge pump is the use of only capacitors as storage elements. The TPS60250/2 charge pumps provide regulated LED current from a 3 V to 6 V input source. The devices operate in two modes. The 1× mode, where the input is connected to the output through a pass element, and a high efficiency 1.5× charge pump mode. The IC maximizes power efficiency by operating in 1× and 1.5× modes as input voltage and LED current conditions require. The mode of operation is automatically selected by comparing the forward voltage of the WLED plus the voltage of current sink for each LED with the input voltage. The IC starts up in 1× mode, and automatically transitions to 1.5× if the voltage at any current sink input (DM_or DS_) falls below the 100 mV transition voltage. The IC returns to 1× mode as the input rises. Figure 13 provides a visual explanation of the 1× to 1.5× transition. In 1.5× mode, the internal oscillator determines the charge/discharge cycles for the flying capacitors. During a charge cycle, the flying capacitors are connected in series and charged up to the input voltage. After the on-time of the internal oscillator expires, the flying capacitors are reconfigured to be in parallel and then connected in series to the input voltage. This provides an output of 1.5× the input voltage. After the off-time of the internal oscillator expires, another charge cycle initiates and the process repeats. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 9 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com VA VO VI VF CP WLED Driver VDX VI x1 Operating Area x1.5 Operating Area VHYS VB VC Figure 13. Input Voltage Hysteresis Between ×1 and ×1.5 Mode As shown in Figure 13, there is input hysteresis voltage between 1× and 1.5× mode to ensure stable operation during mode transition. For the 1 cell Li-Ion battery input voltage range, the TPS6025/2 operate in 1× mode when a fully charged battery is installed. Once the battery voltage drops below the VB level, which is the mode transition voltage from 1× to 1.5×, the WLED driver operates in 1.5× mode. Once in 1.5× mode, the battery voltage must rise to the VC level in order to transition from 1.5× to 1×. This hysteresis ensures stable operation when there is some input voltage fluctuation at the 1×/1.5× mode transition. The transition voltage, VB, depends on VDX (the mode transition threshold voltage), VF (WLED forward voltage drop) and VA (the drop out voltage of the charge pump stage) and is calculated as follows: VB = VA + VF + VDX VA = ROUT1X × ILEDTOTAL Where ROUT1X is the 1× mode output impedance of the IC. See the Electrical Characteristics table for output impedance specifications. The TPS60250/2 switch up to 1.5× mode when the input voltage is below VB and remain in 1.5× mode as long as the input is lower than VC. 1.5× Mode is exited when the input voltage rises above VC. VC is calculated as: VC = VF + 550 mV The input voltage mode transition hysteresis voltage (VHYS) between 1× and 1.5× is calculated using the following equation. VHYS = VC – VB = 550 mV – VDX – VA, where VDX = 100mV Note that VA is the key factor in determining VHYS and is dependant on the 1× mode charge pump output impedance and WLED current. 10 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 LED CURRENT SINKS (DM_, DS_) The TPS60250/2 have constant current sinks which drive seven individual LED current paths. Each current sink regulates the LED current to a constant value determined by the I2C interface. The internal register addressing allows the LED main channels DM1~DM5 to be controlled independently from the LED sub channels DS1~DS2. All LED channels sink up to 25 mA of current except DM5 which has an 80 mA maximum current when configured as an auxiliary output. Using the I2C interface, the user may assign DM5 to the main display bank with up to 25 mA current or as an auxiliary output for torch or keypad light or low/weak camera flash with 80 mA current. DM5 has 64 dimming steps; the same as the main and sub display banks when assigned to the main display. However, it has its own current programming register and enable control. When assigned as an auxiliary, DM5 has 4 dimming steps (full scale, 70%, 40%, 20%). These optimized current sinks minimize the voltage headroom required to drive each LED and maximize power efficiency by increasing the amount of time the controller stays in 1× mode before transitioning to 1.5× mode. OPEN LAMP DETECTION In system production it is often necessary to leave LED current paths open depending on the phone model. For example, one phone may use 2 LEDs to backlight the main display while another uses 4 LEDs. Rather than use two different ICs for these different phone applications, the TPS60250/2 may be used in both applications with no additional efficiency loss in the 2 LED applications. In traditional LED driver applications when an LED current path is open, the current sink voltage falls to ground and the current regulation circuitry drives the output to maximum voltage in an attempt to regulate the current for the missing LED path. This severely reduces system efficiency. The TPS60250/2 use 7 internal comparators to detect open lamp condition, when one or more open LED conditions occur, TPS60250/2 prevent activation of 1.5X mode transition due to missing LEDs. Open lamp detection is enabled/disabled using the I2C interface. CAPACITOR SELECTION The TPS60250/2 are optimized to work with ceramic capacitors with a dielectric of X5R or better. The two flying capacitors must be the same value for proper operation. The 750 kHz switching frequency requires that the flying capacitor be less than 4.7 µF. Use of 1 µF ceramic capacitors for both charge pump flying capacitors is recommended. For good input voltage filtering, low ESR ceramic capacitors are recommended. A 1 µF ceramic input capacitor is sufficient for most applications. For better input voltage filtering this value can be increased to 4.7 µF . The output capacitor controls the amount of ripple on the output. Since small ripple is undetectable by the human eye, a 4.7 µF output capacitor works well. If better output filtering and lower ripple is desired, a larger output capacitor may be used. SETTING THE LED CURRENT Figure 14. Dimming Steps for Sub, Main, and Keypad Backlight Figure 14 shows the dimming steps for sub, main, and auxiliary display banks in a 25 mA maximum current Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 11 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com applications. In order to satisfy today's requirements on LED current , the TPS60250/2 cover the low LED current area from 100 µA to 1.5 mA with 100 µA dimming steps (total 16 steps for a 25 mA maximum current) for the new LCD panels which have improved transparency rates. For LED currents in the range from 2 mA to 25 mA, the devices use 48 dimming steps with 0.5 mA steps. Also, DM5 has 4 dimming steps once the current path is assigned for auxiliary applications with a 80 mA maximum current. SERIAL INTERFACE The serial interface is compatible with the standard and fast mode I2C specifications, allowing transfers at up to 400 kHz. The interface adds flexibility to the WLED driver solution, enabling most functions to be programmed to new values depending on the instantaneous application requirements. Register contents remain intact as long as VCC remains above UVLO2 (typical 1.3 V). For normal data transfer, DATA is allowed to change only when CLK is low. Changes when CLK is high are reserved for indicating the start and stop conditions. During data transfer, the data line must remain stable whenever the clock line is high. There is one clock pulse per bit of data. Each data transfer is initiated with a start condition and terminated with a stop condition. When addressed, the TPS60250/2 devices generate an acknowledge bit after the reception of each byte. The master device (microprocessor) must generate an extra clock pulse that is associated with the acknowledge bit. The TPS60250/2 devices must pull down the DATA line during the acknowledge clock pulse so that the DATA line is a stable low during the high period of the acknowledge clock pulse. Setup and hold times must be taken into account. During read operations, a master must signal the end of data to the slave by not generating an acknowledge bit on the last byte that was clocked out of the slave. In this case, the slave TPS60250/2 devices must leave the data line high to enable the master to generate the stop condition. DATA CLK Data line stable; data valid Change of data allowed Figure 15. Bit Transfer on the Serial Interface CE DATA CLK S P START Condition STOP Condition Figure 16. START and STOP Conditions 12 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 SCLK ... SDAT A6 Start A5 A4 ... ... A0 R/W AC K 0 0 R7 R6 R5 ... ... R0 AC K D7 D6 D5 ...D0 0 Slave Address AC K 0 Register Address Data Stop NOTE: SLAVE=TPS60250 Figure 17. Serial I/F READ From TPS60250/2: Protocol A SCLK SDAT ... A6 .. A0 ... R/W AC K 0 0 R7 .. R0 ... AC K 0 A6 .. A0 ... R/W AC K 1 0 Start Register Address Slave Address Slave Address D7 .. D0 Slave Drives the Data Repeated Start NOTE: SLAVE=TPS60250 AC K Master Drives ACK and Stop Stop Figure 18. Serial I/F READ From TPS60250/2: Protocol B Figure 19. Serial I/F Timing Diagram The I2C interface uses a combined protocol in which the START condition and the Slave Address are both repeated. The TPS60250 provides two I2C Slave Addresses using an internal EEPROM in case more than 1 device is used in the system. The TPS60250 primary I2C Slave Address is 1110111 and the TPS60252 primary I2C Slave Address is 1110110. For the alternative I2C addresses, contact the factory. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 13 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com Enable Control Register (Address: 0x00h) ENABLE B7 B6 B5 B4 B3 B2 B1 B0 X ENold ENmain ENsub2 ENsub1 ENaux DM5H DM5L BIT NAME Bit 6 ENold (Enable Open Lamp Detection) 1: Open Lamp Detection Enabled 0: Open Lamp Detection Disabled Bit 5 ENmain 1: Enable Main Display LEDs (DM1-DM4) 0: Disable Main Display LEDs Bit 4 ENsub2 1: Enable Sub Display LED 2 (DS2) 0: Disable Sub Display LED 2 Bit 3 ENsub1 1: Enable Sub Display LED 1 (DS1) 0: Disable Sub Display LED 1 Bit 2 ENaux 1: Enable Aux Display LED (DM5) 0: Disable Aux Display LED Bits 1,0 DM5H, DM5L DM5H (B1) DM5L (B0) 0 0 Shutdown mode. All outputs disabled but keep register values 0 1 Enable the IC and Group DM5 as main display with maximum current of 25 mA 1 0 Enable the IC and set DM5 as Aux output with maximum current of 80 mA. Dimming steps determined by Iaux0 and Iaux1 bits. 1 1 Shutdown mode. All outputs disabled but keep register values DM5 Mode and Shutdown Mode Sub Display Current Control Register (Address: 0x01h) SUB DISP CURRENT B7 B6 B5 B4 B3 B2 B1 B0 BIT NAME X X Isub5 Isub4 Isub3 Isub2 Isub1 Isub0 Bits 5 - 0 Isub5 - Isub0 (total 64 steps) 6-Bit command (64 steps) to these bits sets the current for DS1 and DS2. For LED currents between 0 and 1.5 mA, one step = 0.1 mA increment For LED currents between 1.5 and 25.5 mA, one step = 0.5 mA increment Main Display Current Control Register (Address: 0x02h) MAIN DISP CURRENT B7 B6 B5 B4 B3 B2 B1 B0 BIT NAME X X Imain5 Imain4 Imain3 Imain2 Imain1 Imain0 Bits 5 - 0 14 Imain5 - Imain0 (total 64 steps) 6-Bit command (64 steps) to these bits sets the current for DM1-DM4. For LED currents between 0 and 1.5 mA, one step = 0.1mA increment For LED currents between 1.5 and 25.5 mA, one step = 0.5 mA increment Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 Aux Output Brightness and Operation Mode Control Register (Address: 0x03h) AUX DISP CURRENT B7 B6 B5 B4 B3 B2 B1 B0 BIT NAME Iaux5 Iaux4 Iaux3 Iaux2 Iaux1 Iaux0 Mode1 Mode0 Bits 7 - 2 (DM5 set to Main Display Mode) Iaux5 - Iaux0 (total 64 steps) 6-Bit command (64 steps) to these bits sets the current for DM5. For LED currents between 0 and 1.5 mA, one step = 0.1mA increment For LED currents between 1.5 and 25.5 mA, one step = 0.5 mA increment Bits 7 - 2 (DM5 set to Aux Display Mode) Bits 1,0 Iaux5 (B7) Iaux4 (B6) Iaux3 (B5) Iaux2 (B4) Iaux1 (B3) Iaux0 (B2) Aux Dimming Step X X X X 0 0 20% X X X X 0 1 40% X X X X 1 0 70% X X X X 1 1 100% Mode1, Mode0 Mode1 Mode0 (B1) (B0) TPS60250/2 Mode 0 0 Auto-Switchover Mode. The TPS60250/2 select 1×/1.5× mode as described in the Operating Principle section. 0 1 1× Mode. TPS60250/2 remain in 1× mode regardless of the input voltage. LED current may not regulate at lower input voltages when in this mode. 1 0 1.5× Mode. TPS60250/2 remain in 1.5× mode regardless of the input voltage. 1 1 Auto-Switchover Mode. The TPS60250/2 select 1×/1.5× mode as described in the Operating Principle section. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 15 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com APPLICATION CIRCUITS Main Display GND DM4 DM3 DM2 C1DM1 C2 1 mF C3 1mF C2+ DS2 C2- DS1 C1+ DM5 VIN SCLK SDAT Sub Display VOUT C4 4.7mF C1 4.7 mF I2C Interface On/Off, Digital Dimming Figure 20. The Typical Application Circuit for Sub and Main Display As shown in Figure 20, typical application circuit for a clam shell phone has 5 main LEDs and 2 sub LEDs. Recently, the LCD panel makers have developed a new panel that has an improved transparency rate which makes system efficiency with 100 µA LED current a critical load point. To meet system efficiency requirements with the light load conditions for the new LCD operating panels, the TPS60250/2 have a maximum 55 µA operating current with 100 µA output load condition. In this application, the controller always operates in 1× mode due to the WLED's low forward voltage drop (about 2.6 VF with a 100 µA WLED current). Thus, the total efficiency at the light load condition is determined using Equation 1: IO VF h Light + Vin ǒI O ) I opǓ (1) Where: IO: Output Load (WLED) Current VF: Forward Voltage Drop of WLED Vin: Input Voltage Iop: Operating Current of LED Driver 16 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 TPS60250 TPS60252 www.ti.com............................................................................................................................................................ SLVS769C – APRIL 2007 – REVISED APRIL 2008 Main Display Auxiliary Port for Key Pad or Flash Light GND DM 4 DM3 DM2 C1DM1 C2 1mF C3 1mF C2+ DS 2 C2- DS 1 C1+ DM5 VIN SCLK SDAT Sub Display VOUT C4 4.7 mF 2 C1 4.7 mF I C Interface On/Off, Digital Dimming Figure 21. The Typical Application Circuit for Sub, Main, and Keypad Backlight Figure 21 shows the typical application circuit for sub, main, and keypad backlight. In this application, DM5 is assigned as the auxiliary input for the keypad lighting application. LAYOUT GUIDELINES There are several points to consider when laying out a PCB for charge pump based solutions. In general, all capacitors should be as close as possible to the device. This is especially important when placing the flying capacitors (C2, C3 in Figure 20 and Figure 21). In cases where DM5 is assigned for torch/flash applications, with a maximum 80 mA WLED current, this current path must be kept wide to reduce the trace resistance. Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 Submit Documentation Feedback 17 TPS60250 TPS60252 SLVS769C – APRIL 2007 – REVISED APRIL 2008............................................................................................................................................................ www.ti.com Revision History Changes from Revision B (November 2007) to Revision C ........................................................................................... Page • 18 Added TPS60252 device information .................................................................................................................................... 1 Submit Documentation Feedback Copyright © 2007–2008, Texas Instruments Incorporated Product Folder Link(s): TPS60250 TPS60252 PACKAGE OPTION ADDENDUM www.ti.com 11-Jul-2008 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty TPS60250RTER ACTIVE QFN RTE 16 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60250RTERG4 ACTIVE QFN RTE 16 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60250RTET ACTIVE QFN RTE 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60250RTETG4 ACTIVE QFN RTE 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60252RTER ACTIVE QFN RTE 16 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60252RTERG4 ACTIVE QFN RTE 16 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60252RTET ACTIVE QFN RTE 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS60252RTETG4 ACTIVE QFN RTE 16 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Lead/Ball Finish MSL Peak Temp (3) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. 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Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 11-Jul-2008 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing TPS60250RTER QFN RTE 16 SPQ Reel Reel Diameter Width (mm) W1 (mm) A0 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS60250RTET QFN RTE 16 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS60252RTER QFN RTE 16 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 TPS60252RTET QFN RTE 16 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 11-Jul-2008 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) TPS60250RTER QFN RTE 16 3000 346.0 346.0 29.0 TPS60250RTET QFN RTE 16 250 190.5 212.7 31.8 TPS60252RTER QFN RTE 16 3000 346.0 346.0 29.0 TPS60252RTET QFN RTE 16 250 190.5 212.7 31.8 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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