SP6699EK-L/TR

SP6699 30V Step Up White LED Driver January 2020 Rev. 3.0.1 GENERAL DESCRIPTION APPLICATIONS The SP6699 is an inductor-based DC/DC converter designed to drive up to six white LEDs in series for LCD modules and keypad backlighting functions. • LCD Modules Only one feedback resistor is needed to control the LED current and obtain the desired brightness. A 1.2MHz constant frequency PWM control scheme is used, enabling the usage of small external components. A typical application needs a 1mm tall inductor and a 0.22μF output capacitor. Additionally, the boost circuit Schottky diode is integrated, further reducing the overall foot print. • GPS Receivers • Keypad Backlighting • Digital Cameras • Portable Media Players FEATURES • High Output Voltage: Up to 30V − Drives 2 to 6 LEDs @ 20mA − High Efficiency up to 84% A logic controlled enable pin allows this device to be placed in a low current consumption mode of a few microamps. Furthermore, the SP6699 is equipped with an over voltage output protection circuit which clamps the output voltage to 30 volts when any LED fails or in other abnormal conditions. • Integrated Schottky Diode The SP6699 is offered in a small lead free, RoHS compliant 6-pin SOT23 package. • Internal Soft Start Circuit • Fast 1.2MHz Switching Frequency • 200mV Feedback Voltage • PWM Dimming Capability up to 2KHz • Over Output Voltage Protection • Small SOT23-6 Package TYPICAL APPLICATION DIAGRAM Fig. 1: SP6699 Application Diagram 1/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver ABSOLUTE MAXIMUM RATINGS OPERATING RATINGS These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. Input Voltage Range VIN ................................ 2.7V to 16V Operating Temperature Range ................... -40°C to 85°C CTRL Voltage VCTRL .................................................. 16V Thermal Resistance (Junction to Ambient) RθJA .....265°C/W Thermal Resistance (Junction to case) RθJC ........... 60°C/W Input Voltage VIN .................................................... 20V SW Voltage ............................................................ 38V FB Voltage ............................................................. 20V CTRL Voltage ......................................................... 20V Operating Junction Temperature............................ 150ºC Storage Temp. Range TSTG ....................... -65ºC to 150ºC Lead Temperature (sold. 10s) TLEAD ..................... 260ºC ESD Ratings – Human Body Model ......................... 2000V ESD Ratings – Machine Model .................................250V Moisture Sensitivity Level (MSL) ................................... 3 ELECTRICAL SPECIFICATIONS Specifications with standard type are for an Operating Junction Temperature of TA = 25°C only; limits applying over the full Operating Junction Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TA = 25°C, and are provided for reference purposes only. Unless otherwise indicated, VIN = 3V, VCTRL = 3V, TA= 25°C. Parameter Min. Operating Voltage 2.5 Feedback Voltage VFB 188 FB Pin Bias Current IFB Typ. Max. Units 16 V 200 212 mV 35 100 nA Conditions • IOUT=20mA, 4 LEDs Supply Current ICC 1.5 2.5 3.2 mA VFB = VIN, not switching Supply Current IQ 2.0 4.0 6.0 µA VCTRL = 0V Switching Frequency f 0.9 1.2 1.5 MHz Maximum Duty Cycle DMAX 90 Switch Current Limit ILIMIT Switch VCE Saturation Voltage VCESAT % mA TA=25°C, D=40% 550 mA TA=25°C, D=80% 360 mV ISW=250mA µA VSW=5V 0.01 Switch Leakage Current CTRL Pin Voltage VCTRL - High 93 550 5 V 1.8 0.5 CTRL Pin Voltage VCTRL – Low V CTRL Bias Current ICTRL 100 µA Schottky Forward Drop VDROP 0.7 V OVP Trip Point 30 V Schottky Leakage Current Soft Start Time t 0.1 ID=150mA 4 µA VR=23V 150 µA VR=27V 300 µs 2/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver BLOCK DIAGRAM Fig. 2: SP6699 Block Diagram PIN ASSIGNMENT Fig. 3: SP6699 Pin Assignment PIN DESCRIPTION Name Pin Number Description SW 1 Switch pin. Connect external inductor GND 2 Ground signal pin FB 3 Voltage Feedback. Reference voltage is 200mV CTRL 4 Shutdown and dimming pin. Connect to 1.8V or higher to enable device; Connect to 0.5V or less to disable device; Connect to a PWM signal of 2kHz or less to achieve LEDs brightness dimming VOUT 5 Output pin. Connected to the cathode of the internal Schottky diode. VIN 6 Input supply pin. Must be locally bypassed. 3/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver ORDERING INFORMATION(1) Part Number SP6699EK-L/TR SP6699EB Temperature Range -40°C ≤ TA ≤ +85°C Package Packing Method Tape & Reel SOT-23-6 SP6699 Evaluation Board Lead Free(2) Yes Notes: 1. Refer to www.maxlinear.com/SP6699 for most up-to-date Ordering Information. 2. Visit www.maxlinear.com for additional information on Environmental Rating. Note that the SP6699 series is packaged in Tape and Reel with a reverse part orientation as per the following diagram 4/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver TYPICAL PERFORMANCE CHARACTERISTICS All data taken at VIN = 3.6V, EN= VIN, RSET=24kΩ, TA = 25°C, unless otherwise specified - Schematic and BOM from Application Information section of this datasheet. Fig. 4: Efficiency vs. Junction Temperature Fig. 5: Efficiency vs. Input Voltage Fig. 6: Efficiency vs. Number of LEDs Fig. 7: Schottky Forward Current vs Schottky Forward Drop Fig. 8: Shutdown Quiescent Current vs Input Voltage Fig. 9: Supply Current vs Input Voltage 5/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver Fig. 11: Input Current in Output Open Circuit vs Input Voltage Fig. 10: Current Limit vs. Duty Cycle Fig. 12: Switching Frequency vs Junction Temperature Fig. 13: Feedback Voltage vs Junction Temperature Fig. 14: Schottky Forward Drop vs Junction Temperature Fig. 15: Schottky Leakage Current vs Junction Temperature 6/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver Fig. 17: Switch Saturation Current vs Switch Current Fig. 16: CTRL Pin Voltage vs. Junction Temperature 7/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver THEORY OF OPERATION LED CURRENT CONTROL DETAILED DESCRIPTION Refer to Figure 18; the LED current is controlled by the feedback resistor R1. LEDs' current accuracy is determined by the regulator's feedback threshold accuracy and is independent of the LED's forward voltage variation. So the precise resistors are preferred. The resistance of R1 is in inverse proportion to the LED current since the feedback reference is fixed at 200mV. The relation for R1 and LED current can be expressed as below: The SP6699 is a boost DC-DC converter which uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the Figure 1 on the first page or Figure 18 below. At the start of each oscillator cycle, the SR latch is set and the switch Q1 turns on. The switch current will increase linearly. The voltage on sense resistor is proportional to the switch current. The output of the current sense amplifier is added to a stabilizing ramp and the result is fed into the non-inversion input of the PWM comparator A2. When this voltage exceeds the output voltage level of the error amplifier A1, the SR latch is reset and the switch is turned off. It is clear that the voltage level at noninversion input of A2 sets the peak current level to keep the output in regulation. This voltage level is the output signal of error amplifier A1, and is the amplified signal of the voltage difference between feedback voltage and reference voltage of 200mV. So, a constant output current can be provided by this operation mode. R1=200mV/ILED OVER VOLTAGE PROTECTION The SP6699 has an internal open-circuit protection circuit. When the LEDs are disconnected from the circuit or fail open, the output voltage is clamped at 30V. The SP6699 will switch at a low frequency, and minimize input current. SOFT START The SP6699 has an internal soft start circuit to limit the inrush current during startup. The startup delay is controlled by internal soft start capacitor. Please refer to Figure 19. Fig. 18: R1 Selection Typical Application Circuit Fig. 19: Soft Start Waveform VIN=3.6V, 5 LEDs, ILED=20mA 8/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver DIMMING CONTROL Two typical types of dimming control circuit are present. First, is providing a PWM input into the CTRL Pin. This is typically preferred in that this will result in constant color from the LED while changing the brightness. Second, changing the feedback voltage to get appropriate duty and luminous intensity is also possible. Fig. 21: Dimming Control using a DC Voltage Second, using a filtered PWM signal can do it. The filtered PWM signal can be considered as a varying and adjustable DC voltage. Adding a control signal to CTRL pin First, adding a PWM Signal to the CTRL pin directly. The SP6699 is turned on or off by the PWM signal when it is applied on the CTRL pin. The typical frequency of this PWM signal is 200Hz to 2KHz. Please refer to figure 20. SP6699 Fig. 22: Dimming Control using a Filtered PWM Voltage Third, is using a logic signal to change the feedback voltage. For example, the FB pin is connected to the GND through a MOSFET and a resistor. And this MOSFET is controlled by a logic signal. The luminous intensity of LEDs will be changed when the MOSFET turns on or off. Fig. 20: Dimming Control using a PWM Signal on CTRL Pin Changing the effective feedback voltage There are three methods effective feedback voltage. to change the First, adding a constant DC voltage through a resistor divider to FB pin can control the dimming. Changing the DC voltage or resistor between the FB Pin and the DC voltage can get appropriate luminous intensity. Comparing with all kinds of PWM signal control, this method features a stable output voltage and LEDs current. Please refer to figure 21. Fig. 23: Dimming Control using Logic Signal 9/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver TYPICAL APPLICATION CIRCUITS 4 White LEDs Driver C: X5R or X7R Dielectric L: Sumida CDRH5D28R-100NC or equivalent For use over the full operating temperature range 5 (or 6) White LEDs Driver C: X5R or X7R Dielectric L: Sumida CDRH5D28R-220NC or equivalent For use over the full operating temperature range 10/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver PACKAGE SPECIFICATION 6-PIN SOT23 Unit: mm (inch) 11/12 Rev. 3.0.1 SP6699 30V Step Up White LED Driver REVISION HISTORY Revision Date Description E 01/21/08 Initial Data Sheet 2.0.0 04/27/09 Reformat of Datasheet Corrections of typographical errors 2.1.0 10/01/2011 3.0.0 04/06/2014 3.0.1 01/24/2020 Inclusion of Tape and Reel part orientation and MSL level information Eliminated analog dimming function on CTRL pin and improved logic level low compatibility for PWM inputs. Increase maximum switch voltage allowing more LEDs in series. Current limit now constant across duty cycle. Shutdown and non-switching Iq slightly changed. Nominal operating frequency increased to 1.2MHz. Reference voltage over temp improved. Recommended maximum PWM dimming frequency increased from 1kHz to 2kHz. Updated to MaxLinear logo. Updated Ordering Information. CORPORATE HEADQUARTERS: 5966 La Place Court Suite 100 Carlsbad, CA 92008 Tel.: +1 (760) 692-0711 Fax: +1 (760) 444-8598 www.maxlinear.com The content of this document is furnished for informational use only, is subject to change without notice, and should not be construed as a commitment by Maxlinear, Inc. Maxlinear, Inc. Assumes no responsibility or liability for any errors or inaccuracies that may appear in the informational content contained in this guide. Complying with all applicable copyright laws is the responsibility of the user. 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