LDS8621002-T2-960

LDS8621 200 mA, Dual Output LED Flash/Lamp Driver FEATURES o Multi-mode charge pump: 1x, 1.33x, 1.5x, 2x Ultra low dropout PowerLite™ Current Regulator* Drives two high-current LEDs up to 96 mA each PWM brightness control o o Power efficiency up to 95% Low noise input ripple in all modes o o Low current shutdown mode Soft start and current limiting o o Short circuit protection Thermal shutdown protection o Tiny 3 x 3 x 0.8 mm 16-pin TQFN package o o o mode and ultra low dropout PowerLite™ Current Regulator increases device’s efficiency up to 95%. New mode requires no additional external capacitors. The PWM1/PWM2 logic inputs function as a chip enable and a PWM mode LED brightness control. PWM1 pin controls LED A, while PWM2 controls bank LED B. APPLICATION o LED Light Supply for Smart Phones, PDAs, and Cell Phones o o LED Flashlights LED Flash/Strobe Applications The maximum LEDs current value is factory preset to 96 mA. Other current values are available upon request. Each LED may be programmed separately. Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multifractional charge pump supports a wide range of input voltages from 2.7V to 5.5V. DESCRIPTION The LDS8621 is a high efficiency multi-mode fractional charge pump with ultra low feedback voltage that can drive up to two high-current LEDs. The inclusion of a 1.33x fractional charge pump The device is available in in 16-lead TQFN 3mm x 3mm package with a max height of 0.8mm. TYPICAL APPLICATION CIRCUIT © 2009 IXYS Corp. Characteristics subject to change without notice 1 Doc. No. 8621DS, Rev. N1.0 LDS8621 ABSOLUTE MAXIMUM RATINGS Parameter Vin, LEDx, C1±, C2± voltage Vout voltage EN/SET voltage Storage Temperature Range Junction Temperature Range Soldering Temperature Rating 6 6.5 Vin + 0.7V -65 to +160 -40 to +125 300 Unit V V V °C °C °C RECOMMENDED OPERATING CONDITIONS Parameter Rating Vin 2.7 to 5.5 Ambient Temperature Range -40 to +85 ILED per LED pin 0 to 96 Total Output Current 0 to 192 Typical application circuit with external components is shown on page 1. Unit V °C mA mA ELECTRICAL OPERATING CHARACTERISTICS (Over recommended operating conditions unless specified otherwise) Vin = 3.6V, Cin = Cout = 1µF, C1 = C2 = 0.22 µF, EN = High, T AMB = 25°C Name Quiescent Current Shutdown Current LED Current Accuracy LED Channel Matching Output Resistance (open loop) Charge Pump Frequency Output short circuit Current Limit Input Current Limit 1x to 1.33x, 1.33x to 1.5x, or 1.5x to 2x Transition Thresholds at any LED pin 1.33x to 1x Mode Transition Hysteresis Transition Filter Delay PWM1, Input Leakage PWM2 High Logic Level Pins Low Thermal Shutdown, T SD Thermal Hysteresis, T SD_HS Under Voltage Lockout (UVLO) Threshold Over Voltage Protection PWM frequency PWM duty cycle © 2009 IXYS Corp. Characteristics subject to change without notice Conditions 1x mode 1.33 x mode 1.5x mode@ 3V 2x mode @ 2.7V Min Typ 1.5 3.5 5.5 6.5 Max mA 1 V EN = 0V 1.5 mA ≤Iled ≤96 mA (ILED - ILEDAVG) / ILEDAVG 1x mode 1.33x mode 1.5x mode 2x mode 1.33x and 2x mode 1.5x mode Vout < 0.5V Vout > 1V ±3 ±3 0.7 3.5 5.5 6.5 0.8 1.1 35 450 ILEDA,B = 60 mA Ω MHz mA mA mV 600 800 mV µs µA 1 0.4 150 20 2.1 2 µA % % 50 -1 1.3 100 1 Units V °C 6.2 100000 100 V V Hz % Doc. No. 8621DS, Rev. N1.0 LDS8621 PIN DESCRIPTION Pin # 1 2 3 4- 6 7 8 9 10 11 12 13 14 15, 16 PAD Name NC LEDA LEDB NC V OUT VIN C1+ C1C2+ C2PWM2 PWM1 GND PAD Function No connect LED A cathode terminal LED B cathode terminal No connect Charge pump output connected to the LED anodes Charge pump input, connect to battery or supply Bucket capacitor 1 Positive terminal Bucket capacitor 1 Negative terminal Bucket capacitor 2 Positive terminal Bucket capacitor 2 Negative terminal LEDB PWM brightness control LEDA PWM brightness control Ground Reference, Connect both pins to GND Connect to GND on the PCB Top view: TQFN 16-lead 3 X 3 mm PIN FUNCTION V IN is the supply pin for the charge pump. A small 1μF ceramic bypass capacitor is required between the Vin pin and ground near the device. The operating input voltage range is from 2.5V to 5.5V. Whenever the input supply falls below the under-voltage threshold (1.8V), all the LED channels are disabled and the device enters shutdown mode. LEDA and LEDB provide the internal regulated current source for each of the LED cathodes. These pins enter high-impedance zero current state whenever the device is in shutdown mode. PAD is the exposed pad underneath the package. For best thermal performance, the pad should be soldered to the PCB and connected to the ground plane V OUT is the charge pump output that is connected to the LED anodes. A small 1μF ceramic bypass capacitor is required between the VOUT pin and ground near the device. PWM1, PWM2 are the enable and PWM LED brightness control logic inputs. Guaranteed levels of logic high and logic low are set at 1.3 V and 0.4 V respectively. When any of PWM pins is taken high, the device becomes enabled with maximum LED current at associated LED. To place the LDS8621 into zero current mode, both PWM pins must be held low for more than 30 ms. GND is the ground reference for the charge pump. The pin must be connected to the ground plane on the PCB. C1+, C1- are connected to each side of the ceramic bucket capacitor C1 C2+, C2- are connected to each side of the ceramic bucket capacitor C2 © 2009 IXYS Corp. Characteristics subject to change without notice 3 Doc. No. 8621DS, Rev. N1.0 LDS8621 BLOCK DIAGRAM Figure 2. LDS8621 Functional Block Diagram BASIC OPERATION At power-up, PWM1 and PWM2 pins should be logic LOW. During power-up device performs internal circuit reset that requires less than 10 µs. To start device, either PWM1 or PWM2 pin should be set logic HIGH. The LDS8621 starts operating in 1x mode, at which the output is approximately equal to the input supply voltage (less any internal voltage losses). If the output voltage is sufficient to regulate all LED currents, the device remains in 1x operating mode. If the input voltage is insufficient or falls to a level where Vd ≤50 mV, and the regulated currents cannot be maintained, the low dropout PowerLite™ Current Regulator switches the charge pump into 1.33x mode (after a fixed delay time of about 800 μs). In 1.33x mode, the charge pump’ output voltage is approximately equal to 1.33 times the input supply voltage (less any internal voltage losses). This sequence repeats at every mode until driver enters the 2x mode. The low dropout PowerLite™ Current regulator (PCR) performs well at input voltages up to 50 mV above LED forward voltage significantly increasing driver’s efficiency. The LDS8621 monitors voltage drop Vd across PCR at every channel in ON state. If this voltage falls below 50 mV (typical) at any one channel, (channel with LED with highest forward voltage), the Mode Control Block changes charge pump mode to the next multiplication ratio. If the device detects a sufficient input voltage is present to drive all LED currents in 1x mode, it will change automatically back to 1x mode. This only applies for changing back to the 1x mode. The difference between the input voltage when exiting 1x mode and returning to 1x mode is called the 1x mode transition hysteresis (about 600 mV). LED Current Setting Vd = V IN x M – V F – Rcp x Iout, where Rcp is a Charge Pump Output Resistance at given mode, Iout is sum of all LED currents, and M is a charge pump’ multiplication ratio. © 2009 IXYS Corp. Characteristics subject to change without notice The maximum current value in each of the LED is factory preset. Each LED has independendet current setting that allows use one of the LEDs for flash, while other for a torch mode. If both LEDs should be used in flash mode, or both cannels are connected in 4 Doc. No. 8621DS, Rev. N1.0 LDS8621 5. Input Voltage Under-Voltage Lockout parallel to provide maximum current through one LED in flash mode, the lower average current value in torch mode may be achieved using PWM. PWM signal may be applied to one of the PWM pins, while other channel is off, or to both PWM pins. The average LED current is proportional PWM duty cycle and number of channels that are in ON state. For instance, if both channels are connected in parallel to provide 196 mA through one LED in flash mode, turning one channel of in torch mode redjuces current to 96 mA, while applying PWM signal with 50% duty cycle to this channel reduces average LED current to 48 mA. LDS8621 allows modulation frequiencies in the range from 100 Hz to 100000 kHz with duty cycle from 100% to 1%. Lower than 100 Hz modulation frequiencies is not recommended especialy at short duty cycles because LED flicker may be visible. If VIN falls below 2.2 V (typical value), LDS8621 enters shutdown mode. Device requires restart when input voltage rises above 2.3 V. 6. Low VIN or High LED V F Voltage Detection If, in 2x mode, VIN is too low to maintain regulated LED current for given LED VF, or LED becomes an open circuit, or if any LED at active channels is disconnected, LDS8621 starts subsequently changing modes (2x – 1x – 1.33x -1.5x – 2x -…) in an attempt to compensate insufficient voltage. As a result, average current at all other channels that are ON may be below regulated level. LED Selection LEDs with forward voltages (VF ) ranging from 1.6V to 4.5V may be used. Charge pumps operate in the highest efficiency mode when V F voltage is close to Vin voltage multiplied by switching mode, i.e. Vin x 1, Vin x 1.33 and so on. If the voltage source is a Li-ion battery, we recommend selecting LED with VF = 2.7 – 3.6 V to extend the battery life and achieve highest efficiency. The LDS8621 has follow protection modes: 1. LED short to V OUT protection If LED pin is shorted to V OUT, LED burned out becomes as short circuit, or LED pin voltage is within (VOUT - 1.5V) range, LDS8621 recognizes this condition as “LED Short” and disables this channel with 750 µA control current. If LED pin voltage is less than (Vout – 1.5V), LDS8621 restores LED current at this particular channel to programmed value. External Components The LDS8621 requires two external 1µF ceramic capacitors (X5R or X7R type) for decoupling input, output, and two 0.22 µF capacitors the same type for the charge pump. In all charge pump modes, the input current ripple is very low, and an input bypass capacitor of 1µF is sufficient. 2. V OUT Over-Voltage Protection The charge pump’ output voltage V OUT automatically limits at about 6.2 V maximum. This is to prevent the output pin from exceeding its absolute maximum rating. In 1x mode, the device operates in linear mode and does not introduce switching noise back onto the supply. 3. V OUT Short Circuit Protection If VOUT is shorted to ground before LDS8621 is enabled, input current may increase up to 200 – 300 mA within 20 µs after enable and is limited to 35 – 40 mA after that. Recommended Layout In charge pump mode, the driver switches internally at a high frequency. It is recommended to minimize trace length to all four capacitors. A ground plane should cover the area under the driver IC as well as the bypass capacitors. Short connection to ground on capacitors Cin and Cout can be implemented with the use of multiple via. A copper area matching the TQFN exposed pad (PAD) must be connected to the ground plane underneath. The use of multiple via improves the package heat dissipation. 4. Over-Temperature Protection If the die temperature exceeds +150°C, the driver will enter shutdown mode. The LDS8621 requires restart after die temperature falls below 130°C. © 2009 IXYS Corp. Characteristics subject to change without notice 5 Doc. No. 8621DS, Rev. N1.0 LDS8621 PACKAGE DRAWING AND DIMENSIONS 16-PIN TQFN (HV3), 3mm x 3mm, 0.5mm PITCH SYMBOL A A1 A2 b D D1 E E1 e L MIN 0.70 0.00 0.178 0.18 2.90 1.40 2.90 1.40 0.35 NOM 0.75 0.02 0.203 0.23 3.00 1.55 3.00 1.55 0.50 typ 0.40 MAX 0.80 0.05 0.228 0.28 3.10 1.70 3.10 1.70 0.45 Note: 1. All dimensions are in millimeters 2. Complies with JEDEC Standard MO-220 © 2009 IXYS Corp. Characteristics subject to change without notice 6 Doc. No. 8621DS, Rev. N1.0 LDS8621 ORDERING INFORMATION Part Number LDS8621 002-T2 Notes: 1. 2. Package Package Marking (1) TQFN-16 3 x 3mm 8621 Matte-Tin Plated Finish (RoHS-compliant) Quantity per reel is 2000 EXAMPLE OF ORDERING INFORMATION Prefix LDS Device # Suffix 8621 002 Product Number Optional Company ID Package T2 Tape & Reel T: Tape & Reel 2: 2000/Reel 002: 3x3 TQFN Notes: 1) All packages are RoHS-compliant (Lead-free, Halogen-free). 2) The standard lead finish is Matte-Tin. 3) The device used in the above example is a LDS8621 002–T2 ( 3x3 TQFN, Tape & Reel). 4) For additional package and temperature options, please contact your nearest IXYS Corp. Sales office. © 2009 IXYS Corp. Characteristics subject to change without notice 7 Doc. No. 8621DS, Rev. N1.0 LDS8621 Warranty and Use IXYS CORP. MAKES NO WARRANTY, REPRESENTATION OR GUARANTEE, EXPRESS OR IMPLIED, REGARDING THE SUITABILITY OF ITS PRODUCTS FOR ANY PARTICULAR PURPOSE, NOR THAT THE USE OF ITS PRODUCTS WILL NOT INFRINGE ITS INTELLECTUAL PROPERTY RIGHTS OR THE RIGHTS OF THIRD PARTIES WITH RESPECT TO ANY PARTICULAR USE OR APPLICATION AND SPECIFICALLY DISCLAIMS ANY AND ALL LIABILITY ARISING OUT OF ANY SUCH USE OR APPLICATION, INCLUDING BUT NOT LIMITED TO, CONSEQUENTIAL OR INCIDENTAL DAMAGES. IXYS Corp. products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the IXYS Corp. product could create a situation where personal injury or death may occur. IXYS Corp. reserves the right to make changes to or discontinue any product or service described herein without notice. Products with data sheets labeled "Advance Information" or "Preliminary" and other products described herein may not be in production or offered for sale. IXYS Corp. advises customers to obtain the current version of the relevant product information before placing orders. Circuit diagrams illustrate typical semiconductor applications and may not be complete. IXYS Corp. 1590 Buckeye Dr., Milpitas, CA 95035-7418 Phone: 408. 457.9000 Fax: 408.496.0222 http://www.ixys.com © 2009 IXYS Corp. Characteristics subject to change without notice Document No: 8621DS Revision: N1.0 Issue date: 10/7/2009 8 Doc. No. 8621DS, Rev. N1.0