AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications General Description Features The AAT3129 is a high efficiency charge pump DC/DC converter with tri-mode load switch (1X) fractional (1.5X) and doubling (2X) conversion for color LED applications. A single current source output provides a regulated current to drive R, G, and B LEDs via three internal switches. With a simple single wire serial bus, the RGB module can be easily controlled to display 4096 colors. • • • • • • • • • • • • AnalogicTech's Advanced Simple Serial Control™ (AS2Cwire™) serial digital input is used to enable, disable, and set the duty cycle of each internal MOSFET switch. Low external parts count (two 1μF flying capacitors and two small bypass capacitors at VIN and OUT) makes the AAT3129 ideally suited for small battery-powered applications. ChargePump™ VIN Range: 2.7V to 5.5V Common Anode RGB LED Control 4096 Color with Single Wire Digital Control 40mA to 180mA Fixed Current Source AS2Cwire Digital Brightness Control Low Noise Constant Frequency Operation Small Application Circuit Regulated Output Current No Inductors 1MHz Switching Frequency IQ <1μA in Shutdown 12-Pin TSOPJW Package Applications The AAT3129 has a thermal management system to protect the device in the event of a short-circuit condition on any of the output pins. Built-in softstart circuitry prevents excessive inrush current during start-up. High switching frequency enables the use of small external capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1μA. • • • • • • • • The AAT3129 is available in a Pb-free, 12-pin TSOPJW package. Fashion RGBs Mobile Handsets MP3 Players PDAs Portable Devices RGB Color LEDs RGB Photo Flash Smart Phones Typical Application VIN ISRC C1+ VBAT CP CIN 1μF CCP 1μF AAT3129 C1 1μF R C1C2+ G B C2 1μF C2EN/SET EN/SET DR DG DB GND 3129.2007.01.1.4 1 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Pin Descriptions Pin # Symbol Function 1 C2+ Flying capacitor 2 positive terminal. Connect a 1μF capacitor between C2+ and C2-. 2 CP Charge pump output. Requires 1μF capacitor connected between this pin and ground. 3 C1- Flying capacitor 1 negative terminal. 4 C1+ Flying capacitor 1 positive terminal. Connect a 1μF capacitor between C1+ and C1-. 5 ISRC Current source output. 6 EN/SET 7 DB Open drain switch blue diode cathode. 8 DG Open drain switch green diode cathode. 9 DR Open drain switch red diode cathode. 10 GND 11 IN 12 C2- AS2Cwire control pin. Ground. Input power supply. Requires 1μF capacitor connected between this pin and ground. Flying capacitor 2 negative terminal. Pin Configuration TSOPJW-12 (Top View) C2+ CP C1C1+ ISRC EN/SET 2 1 12 2 11 3 10 4 9 5 8 6 7 C2IN GND DR DG DB 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Absolute Maximum Ratings1 Symbol VIN VCP VEN/SET VEN/SET(MAX) TJ TLEAD Description Input Voltage Charge Pump Output EN/SET to GND Voltage Maximum EN/SET to Input Voltage Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6 -0.3 to 6 -0.3 to 6 0.3 -40 to 150 300 V V V V °C °C Value Units 625 160 mW °C/W Thermal Information Symbol PD θJA Description Maximum Power Dissipation Thermal Resistance 2, 3 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. 3. Derate 6.25mW/°C above 25°C. 3129.2007.01.1.4 3 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Electrical Characteristics1 VIN = 3.5V, CIN = CCP = C1 = C2 = 1μF; TA = -40°C to +85°C. Unless otherwise noted, typical values are TA = 25°C. Symbol Description Input Power Supply VIN Operation Range ICC Operating Current ISHDN ISRC Charge Pump TS FCLK η Switches RDS(ON) EN/SET VEN(L) VEN(H) TEN/SET LO TEN/SET HI MIN TOFF TLAT IEN/SET Shutdown Current Output Current Accuracy Conditions Min Typ Max Units 1 5.5 3 V mA 1 5 μA % 2.7 3.0 ≤ VIN ≤ 5.5, CP = 1.5X, No Load Current EN = 0 3.0 ≤ VIN ≤ 5.5 Start-Up Delay Time Clock Frequency Efficiency VIN = 3.5V Switch On Resistance VIN = 3.5V, TA = 25°C Enable Threshold Low Enable Threshold High EN/SET Low Time Minimum EN/SET High Time EN/SET Off Timeout EN/SET Latch Timeout EN/SET Input Leakage VIN = 2.7V VIN = 5.5V -5 200 1 93 1.4 0.3 μs MHz % 1.5 Ω 0.4 V V μs ns μs μs μA 75 50 VEN/SET = 5.5V, VIN = 5.5V -1 500 500 1 1. The AAT3129 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 4 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Typical Characteristics Turn-On to 1X Mode Turn-On to 1.5X Mode (VIN = 4.2V; ISRC = 60mA) (VIN = 3.6V; ISRC = 60mA) EN/SET (2V/div) EN/SET (2V/div) CP (2V/div) CP (2V/div) IISRC (50mA/div) IISRC (50mA/div) μs/div 100μ μs/div 100μ Turn-On to 2X Mode Turn-Off from 1.5X Mode (VIN = 2.8V; ISRC = 60mA) (VIN = 3.6V; Addr = 2; Data = 16) EN/SET (2V/div) EN/SET (2V/div) VISRC (2V/div) CP (2V/div) IISRC (50mA/div) IISRC (50mA/div) μs/div 100μ 3129.2007.01.1.4 μs/div 100μ 5 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Typical Characteristics Operating Characteristics Operating Characteristics (VIN = 4.2V; DR, DB, and DG in 1X Mode) (VIN = 3.9V; DR and DG in 1X Mode; DB in 1.5X Mode) 4.1V CP (1V/div) CP (1V/div) VISRC (1V/div) VISRC (1V/div) IISRC (50mA/div) IISRC (50mA/div) μs/div 100μ 5.2V 3.8V μs/div 100μ Operating Characteristics Line Response (VIN = 3.6V; DR in 1X Mode; DG and DB in 1.5X Mode) (1X Mode; IISRC = 60mA) 5.3V CP (1V/div) VISRC (1V/div) 3.5V VIN (1V/div) VCP (1V/div) 3.7V 4.2V VISRC (1V/div) IISRC (50mA/div) IISRC (50mA/div) μs/div 100μ 1ms/div Line Response (1X, 1.5X Mode; IISRC = 60mA) VIN (1V/div) VCP (1V/div) 3.5V 3.9V VISRC (1V/div) IISRC (50mA/div) 1ms/div 6 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Typical Characteristics Oscillator Frequency vs. Temperature Shutdown Current vs. Temperature 1 1.5 Shutdown Current (μA) 1.4 FOSC (MHz) 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 -40 -20 0 20 40 60 80 0.1 0.01 0.001 -40 100 -20 0 20 Temperature (°°C) 60 80 100 Temperature (°°C) IISRC vs. VIN IISRC vs. VF (VF = 3.5V) (VIN = 3.5V) 64 64 63 63 +25°C 62 62 61 +25°C 61 IISRC (mA) IISRC (mA) 40 60 +85°C 59 58 57 60 +85°C 59 58 57 -40°C 56 56 55 55 54 -40°C 54 2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 1.0 5.5 1.5 2.0 2.5 VIN (V) 3.0 3.5 4.0 VF (V) TLAT vs. VIN TOFF vs. VIN 450 350 400 -40°C 300 350 TOFF (μ μs) TLAT (μ μs) 300 250 +85°C +25°C 200 150 100 -40°C 250 200 +85°C +25°C 150 100 50 50 0 2.7 3.0 3.3 3.5 3.8 4.1 4.4 Input Voltage (V) 3129.2007.01.1.4 4.7 4.9 5.2 5.5 2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5 Input Voltage (V) 7 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Typical Characteristics Switch Resistance vs. Supply Voltage VIH vs. VIN 1050 1000 1.2 +85°C 950 1.0 VIH (mV) Switch Resistance (Ω Ω) 1.4 0.8 0.6 850 800 750 +85°C +25°C 700 -40°C +25°C -40°C 900 650 0.4 600 0.2 550 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 4.7 4.9 5.1 5.3 5.5 Supply Voltage (V) 2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5 Input Voltage (V) VIL vs. VIN 1050 1000 VIL (mV) 950 900 -40°C 850 800 750 700 +25°C 650 +85°C 600 550 2.7 3.0 3.3 3.5 3.8 4.1 4.4 4.7 4.9 5.2 5.5 Input Voltage (V) 8 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Functional Block Diagram VIN Soft Start 1MHz Oscillator C1+ 1X 1.5X 2X Charge Pump Voltage Reference C1C2+ C2CP ISRC DR EN/SET AS2Cwire Interface DG Control DB GND Functional Description become close to dropout, the charge pump will automatically transition to 2X mode. The AAT3129 is a tri-mode load switch (1X) and high efficiency (1.5X or 2X) charge pump device intended for fashion color LED lighting applications. To maximize power conversion efficiency, an internal sensing circuit monitors the voltage required on the constant current source output and sets the load switch and charge pump modes based on the input battery voltage and the current source output voltage. As the battery discharges over time, the AAT3129 charge pump is enabled when the current source output nears dropout. The charge pump initially starts in 1.5X mode. If the charge pump output drops enough for the current source output to The AAT3129 requires only four external components: two 1μF ceramic capacitors for the charge pump flying capacitors (C1 and C2), one 1μF ceramic input capacitor (CIN), and one 0.33μF to 1μF ceramic output capacitor (CP). 3129.2007.01.1.4 The color and brightness of an RGB color LED is maintained by PWM signals, which are programmed via the AS2Cwire interface. The control block generates three gate drive PWM signals for the N-channel MOSFET switches. Please refer to the interface description and timing in the following section for details. 9 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Applications Information pin has been held high for time TLAT. Address or data is differentiated by the number of EN/SET rising edges. Since the data registers are 4 bits each, the differentiating number of pulses is 24 or 16, so that address 1 is signified by 17 rising edges, address 2 by 18 rising edges, and so forth. Data is set to any number of rising edges between 1 and including 16. A typical write protocol is a burst of EN/SET rising edges, signifying a particular address, followed by a pause with EN/SET held high for the TLAT timeout period, a burst of rising edges signifying data, and a TLAT timeout for the data registers. Once an address is set, then multiple writes to the corresponding data register are allowed. AS2Cwire Serial Interface The Advanced Simple Serial Control digital interface is used to set the color, overall intensity, and method of update for the R, G, and B channels. The intensity for each channel is set by dedicated 4-bit registers giving each channel 16 levels of brightness and resulting in 4096 possible color combinations. In addition to the three color registers, there is an intensity register and a mode register. The intensity register sets the overall intensity and provides 16 global brightness levels. The mode register toggles the method of update between two possibilities. Depending on the mode register setting, the AAT3129 will update the R, G, and B channels immediately or update them only when the intensity register is updated. When EN/SET is held low for an amount of time greater than TOFF, the AAT3129 enters into shutdown mode and draws less than 1μA from the supply. Address 1 is the default address on the first rising edge after the AAT3129 has been disabled. When shutdown mode is entered, the Address and Data registers are reset to 1. AS2Cwire relies on the number of rising edges of the EN/SET pin to address and load the registers. AS2Cwire latches data or address after the EN/SET AS2Cwire Serial Interface Timing Address Data THI TLO T LAT T LAT EN/SET 1 2 17 18 1 2... 1 Address n <= 16 2 G 1 R, B, T, M 1 n AS2Cwire Serial Interface Addressing 10 Address EN/SET Rising Edges Data Register Description 1 2 3 4 5 17 18 19 20 21 R G B T M Red Green Blue Intensity Mode 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Color Registers R, G, and B Intensity Register T The individual color brightness is set using the three R, G, and B registers. The data register contents determine the on-time for each color channel during a PWM cycle. The first level is 0, or off, and is set with a single EN/SET rising edge. This setting eliminates a given color from the spectrum. The remaining 15 levels progressively increase the brightness for a particular color by increasing that channel’s on-time. Using the red channel as an example, the resulting on-time is The overall intensity level is set by the T register. Once a particular mixing of colors is set to produce the desired color, the overall intensity can be adjusted while keeping constant the ratio of colors to one another. The brightest level is set by programming the T register with 1 edge. Programming the T register with 16 edges produces the dimmest setting. The T register adjusts the overall intensity by controlling the PWM off-time. Under the dimmest setting, the off-time is the longest. The offtime that results from the data in the T register is on-time = (R - 1) · 128μs off-time = (T - 1) · 512μs where R is the data setting (from 1 to 16). The same applies to G and B. Diode Current Timing (R - 1) · 128μs Red ISRC 128μs (T - 1) · 512μs ISRC (G - 1) · 128μs Green ISRC 128μs (B - 1) · 128μs Blue Mode Register M The mode register determines the method of update for the R, G, and B channels. When the mode register is set to 1, the addressed color updates immediately. When the mode register is set to 2, the colors will update when the T register is written (synchronized updating). Under immediate updating, an addressed channel will update as soon as new data has latched for it. Under synchronized updating, the channels that have been assigned new data will not update until data for the T register latches. 3129.2007.01.1.4 ISRC 128μs By using synchronized updating, discrete changes in color can be achieved. Synchronized updating allows the intensity for all three colors to be updated simultaneously. All three color registers can be loaded with new data prior to the update. Then, upon loading the T register, all three colors will change to their new states together. This allows a user to transition from one mixed color to another without having to traverse intermediate colors. Under immediate updating color changes can only be achieved serially, or one color at a time. 11 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Mode Register Settings - Address 5 M Setting 1 2 Action R, G, B, T Registers Latched Independently R, G, B Registers Synchronized to T Register Latch LED Current The resulting DC current for each of the R, G, and B channels depends on the overall system settings. Using the overall settings, the current for a particular channel is calculated as R-1 IR = ISRC · 4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ON G-1 IG = ISRC · 4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ON B-1 IB = ISRC · 4 · (T - 1) + (R - 1) + (G - 1) + (B - 1) + CHLS_ON where ISRC is the factory programmed current and CHLS_ON is the number of channels programmed to operate. Whenever a channel is programmed to Data = 1, that channel is programmed to off and must be removed from the CHLS_ON count. Capacitor Selection Careful selection of the four external capacitors CIN, C1, C2, and COUT is important because they will affect turn-on time, output ripple, and transient performance. Optimum performance will be obtained when low equivalent series resistance (ESR) ceramic capacitors are used. In general, low ESR may be defined as less than 100mΩ. For best overall performance, 1μF capacitors are recommended. Depending on ripple requirements, the input and output capacitor values can be increased or decreased accordingly. If lower ripple is desired, increase the capacitor value. The peak-to-peak ripple seen at the input or output increases or decreases with capacitor size. 12 Capacitor Characteristics Ceramic composition capacitors are highly recommended over all other types of capacitors for use with the AAT3129. Ceramic capacitors offer many advantages over their tantalum and aluminum electrolytic counterparts. A ceramic capacitor typically has very low ESR, is lowest cost, has a smaller PCB footprint, and is non-polarized. Low ESR ceramic capacitors help maximize charge pump transient response. Since ceramic capacitors are non-polarized, they are not prone to incorrect connection damage. Equivalent Series Resistance ESR is an important characteristic to consider when selecting a capacitor. ESR is a resistance internal to a capacitor that is caused by the leads, internal connections, size or area, material composition, and ambient temperature. Capacitor ESR is typically measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Ceramic Capacitor Materials Layout Considerations Ceramic capacitors less than 0.1μF are typically made from NPO or C0G materials. NPO and C0G materials typically have tight tolerance and are stable over temperature. Larger capacitor values are typically composed of X7R, X5R, Z5U, or Y5V dielectric materials. Large ceramic capacitors, typically greater than 2.2μF, are often available in lowcost Y5V and Z5U dielectrics, but capacitors greater than 1μF are typically not required for AAT3129 applications. The AAT3129 is a high-performance device that operates with a high switching frequency. To ensure optimal device performance and accommodate the fast transients generated by the AAT3129 special attention should be given to the board layout. The recommended layout is illustrated in Figure 1. The traces connecting C1 and C2 experience fast current transients. As a result, the trace lengths for C1 and C2 should be minimized by placing the components as closely as possible to the IC. This will minimize path resistance and reduce ringing due to the inductance associated with trace length. For best IC performance, CIN and COUT are placed as closely as possible to the IN and CP pins and are connected to a solid ground. Capacitor area is another contributor to ESR. Capacitors that are physically large will have a lower ESR when compared to a smaller capacitor made from an equivalent material. These larger devices can improve circuit transient response when compared to an equal value capacitor in a smaller package size. GND C2 COUT CIN C1 GND Figure 1: Optimal PCB Layout. 3129.2007.01.1.4 13 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications Ordering Information Output Current Package Marking1 Part Number (Tape and Reel)2 60mA TSOPJW-12 NNXYY AAT3129ITP-60-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Package Information 2.85 ± 0.20 + 0.10 - 0.05 2.40 ± 0.10 0.20 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 7° NOM 0.04 REF 0.055 ± 0.045 0.15 ± 0.05 + 0.10 1.00 - 0.065 0.9625 ± 0.0375 3.00 ± 0.10 4° ± 4° 0.45 ± 0.15 0.010 2.75 ± 0.25 All dimensions in millimeters. 1. XYY = assembly and date code. 2. Sample stock is held on part numbers listed in BOLD. 14 3129.2007.01.1.4 AAT3129 High Efficiency 1X/1.5X/2X Charge Pump for RGB Color LED Applications © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737- 4600 Fax (408) 737- 4611 3129.2007.01.1.4 15