DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs General Description Features The AAT1239-1 is a high frequency, high efficiency constant current boost converter capable of driving up to ten (10) series-connected white LEDs or 40V. It is an ideal power solution for backlight applications with up to ten white LEDs in series. The input voltage is 2.7V to 5.5V for single-cell lithium-ion/polymer (Li-ion) based portable devices. • Input Voltage Range: 2.7V to 5.5V • Maximum Continuous Output 40V @ 30mA • Drives up to 10 LEDs in Series ▪Constant LED Current with 3.5% Accuracy Over Temperature and Input Voltage Range • Digital Control with S2Cwire Single Wire Interface ▪ 26 Discrete Steps ▪ No PWM Control Required ▪ No Additional Circuitry • Up to 85% Efficiency • Up to 2MHz Switching Frequency Allows Small External Chip Inductor and Capacitors • Hysteretic Control ▪ No External Compensation Components ▪ Excellent Load Transient Response ▪ High Efficiency at Light Loads • Integrated Soft Start with No External Capacitor • True Load Disconnect Guarantees <1.0µA Shutdown Current • Selectable Feedback Voltage Ranges for High Resolution Control of Load Current • Short-Circuit, Over-Voltage, and Over-Temperature Protection • 12-Pin TSOPJW Package • -40°C to +85°C Temperature Range The LED current is digitally controlled across a 6x operating range using Skyworks’ Simple Serial Control (S2Cwire™) interface. Programmability across 26 discrete current steps provides high resolution, low noise, flicker-free, constant LED outputs. In programming AAT1239 operation, LED brightness increases based on the data applied at the EN/SET pin. The SEL logic pin changes the feedback voltage between two programmable ranges. The AAT1239-1 features a high current limit and fast, stable transitions for stepped or pulsed current applications. The high switching frequency (up to 2MHz) provides fast response and allows the use of ultra-small external components, including chip inductors and capacitors. Fully integrated control circuitry simplifies design and reduces total solution size. The AAT1239-1 offers a true load disconnect feature which isolates the load from the power source while in the OFF or disabled state. This eliminates leakage current, making the devices ideally suited for battery-powered applications. Applications The AAT1239-1 is available in the Pb-free, thermallyenhanced 12-pin TSOPJW package. • • • • • Color Display Backlight Digital Still Cameras (DSCs) Digital Photo Frames PDAs and Notebook PCs White LED Drivers Typical Application L1 2.2µH PVIN Li-Ion: VIN = 2.7V to 4.2V C1 2.2µF VIN DS1 SS16L or equivalent LIN SW R2 374kΩ AAT1239-1 C2 2.2µF M673 OVP Enable/Set Feedback Voltage Select EN/SET R3 12kΩ SEL FB PGND AGND ILED 20mA R1 (RBALLAST) 30.1Ω White LEDs OSRAM LW M678 or equivalent Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 1 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Pin Descriptions Pin # Symbol 1 2 PVIN EN/SET 3 SEL 4 5 6, 7 8 9 10 11 12 VIN N/C SW PGND AGND FB OVP LIN Function Input power pin; connected to the source of the P-channel MOSFET. Connect to the input capacitor(s). IC enable pin and S2Cwire input control to set output current. FB voltage range select. A logic LOW sets the FB voltage range from 0.4V to 0.1V; a logic HIGH sets the FB voltage range from 0.6V to 0.3V. Input voltage for the converter. Connect directly to the PVIN pin. No connection. Boost converter switching node. Connect the power inductor between this pin and LIN. Power ground for the boost converter. Ground pin. Feedback pin. Connect a resistor to ground to set the maximum LED current. Feedback pin for over-voltage protection sense. Switched power input. Connect the power inductor between this pin and SW. Pin Configuration TSOPJW-12 (Top View) 2 PVIN 1 12 LIN EN/SET 2 11 OVP SEL 3 10 FB VIN 4 9 AGND N/C 5 8 PGND SW 6 7 SW Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Part Number Descriptions Part Number AAT1239ITP-1 HIGH SEL Polarity 0.6V ≥ VFB ≥ 0.3V LOW 0.4V ≥ VFB ≥ 0.1V S2C Feedback Voltage Programming See Table 2 Absolute Maximum Ratings1 TA = 25°C unless otherwise noted. Symbol Description PVIN, VIN SW LIN, EN/SET, SEL, FB TJ TS TLEAD Input Voltage Switching Node Maximum Rating Operating Temperature Range Storage Temperature Range Maximum Soldering Temperature (at leads, 10 sec) Value Units -0.3 to 6.0 45 VIN + 0.3 -40 to 150 -65 to 150 300 V V V °C °C °C Value Units 160 625 °C/W mW Thermal Information Symbol qJA PD Description Thermal Resistance Maximum Power Dissipation 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. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 3 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Electrical Characteristics1 TA = -40°C to +85°C unless otherwise noted. Typical values are at 25°C, VIN = 3.6V. Symbol Description Power Supply PVIN, VIN VOUT(MAX) IQ ISHDN IOUT DVLINEREG(FB)/DVIN RDS(ON) L RDS(ON) IN TSS Input Voltage Range Maximum Output Voltage Operating Current Shutdown Current Maximum Continuous Output Current2 Line Regulation Low Side Switch On Resistance Input Disconnect Switch On Resistance Soft-Start Time VOVP ILIMIT TSD THYS SEL, EN/SET VSEL(L) VSEL(H) VEN/SET(L) VEN/SET(H) TEN/SET (LO) TEN/SET(HI) TOFF TLAT IEN/SET Over-Voltage Protection Threshold Over-Voltage Hysteresis N-Channel Current Limit TJ Thermal Shutdown Threshold TJ Thermal Shutdown Hysteresis SEL Threshold Low SEL Threshold High Enable Threshold Low Enable Threshold High EN/SET Low Time EN/SET High Time EN/SET Off Timeout EN/SET Latch Timeout EN/SET Input Leakage Conditions Min Typ Max Units SEL = GND, FB = 0.1V EN/SET = GND 5.5 40 70 1.0 V V µA µA 2.7V < VIN < 5.5V, VOUT = 40V 30 mA 2.7 VIN = 2.7V to 5.5V, VFB = 0.6V From Enable to Output Regulation; VFB = 300mV VOUT Rising VOUT Falling 1.1 0.7 135 % mW 180 mW 400 µs 1.2 100 2.5 140 15 1.3 V mV A °C °C 0.4 V V V V µs µs µs µs µA 1.4 0.4 VEN/SET VEN/SET VEN/SET VEN/SET VEN/SET < > < > = 0.6V 1.4V 0.6V 1.4V 5V VIN = 5V 1.4 0.3 75 75 500 500 1 -1 AAT1239-1 VFB FB Pin Regulation VIN = 2.7V to 5.5V, SEL = GND, EN/SET = DATA16 VIN = 2.7V to 5.5V, SEL = HIGH, EN/SET = HIGH 0.085 0.1 1.115 0.54 0.6 0.66 1. Specification over the -40°C to +85°C operating temperature range is assured by design, characterization, and correlation with statistical process controls. 2. Maximum continuous output current increases with reduced output voltage, but may vary depending on operating efficiency and thermal limitations. 4 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 V DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Typical Characteristics Efficiency vs. LED Current Efficiency vs. LED Current (9 White LEDs; RBALLAST = 30.1Ω) 80 78 78 76 VIN = 5V Efficiency (%) Efficiency (%) (10 White LEDs; RBALLAST = 30.1Ω) VIN = 5V 76 74 72 70 VIN = 3.6V VIN = 4.2V 68 VIN = 3.6V VIN = 4.2V 70 66 2 4 6 8 10 12 14 16 18 2 20 ILED (mA) 8 10 12 14 16 Line Transient (10 White LEDs; RBALLAST = 30.1Ω) Input Voltage (top) (V) Output Voltage (middle) (V) 85°C 0.4 0.2 -40°C 0.0 3.1 3.5 3.9 4.3 4.7 5.1 20 4.2V 3.6V 33.2 33 32.8 0.62 0.6 0.58 Feedback Voltage (bottom) (V) 0.6 18 ILED (mA) (EN = GND) 25°C 5.5 Input Voltage (V) Time (50µs/div) Accuracy ILED vs. Input Voltage Accuracy ILED vs. Temperature (VFB = 0.6V; RBALLAST = 30.1Ω) (VFB = 0.6V; RBALLAST = 30.1Ω) 1.5 2.0 1.5 1.0 Accuracy ILED (%) -40°C 1.0 0.5 0.0 85°C 25°C -0.5 -1.0 -1.5 -2.0 2.7 6 Shutdown Current vs. Input Voltage 0.8 2.7 4 1.0 Shutdown Current (µA) 72 68 66 Accuracy ILED (%) 74 3.2 3.7 4.2 4.7 Input Voltage (V) 5.2 0.5 0.0 -0.5 -1.0 -1.5 -40 5.7 -15 10 35 60 85 Temperature (°C) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 5 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Soft Start (10 White LEDs; VFB = 0.3V) 0V 0.4 0.2 0 2 1 0 Time (200µs/div) 3.3V 0V 0.2 2 0 1 0 Time (200µs/div) 0.4 0.2 0.5 0.0 EnableVoltage (top) (V) Feedback Voltage (middle) (V) 0.6 Time (100µs/div) 3.3V 0V 0.4 0.2 0 0.5 0 Time (50µs/div) Output Ripple VIN = 4.2V (10 White LEDs; VIN = V3.6V; COUT = 2.2µF; ILED = 13mA) IN = 3.6V VIN = 2.7V Output Ripple VIN = 4.2V (10 White LEDs; VIN = V3.6V; COUT = 2.2µF; ILED = 20mA) IN = 3.6V VIN = 2.7V VOUT (AC Coupled) (20mV/div) VOUT (AC Coupled) (20mV/div) VSW (20V/div) VSW (20V/div) IL (500mA/div) IL (500mA/div) 6 Inductor Current (bottom) (A) 0V Inductor Current (bottom) (A) EnableVoltage (top) (V) Feedback Voltage (middle) (V) Shutdown VIN = 4.2V (10 LEDs; VFB = 0.3V) = 3.6V VIN VIN = 2.7V 3.3V Time (200ns/div) 0V 0.4 Shutdown VIN = 4.2V (10 White LEDs; 3.6V VIN = V FB = 0.6V) VIN = 2.7V 0 EnableVoltage (top) (V) Inductor Current (bottom) (A) 3.3V 0.6 Feedback Voltage (middle) (V) Soft Start (10 White LEDs; VFB = 0.6V) EnableVoltage (top) (V) Inductor Current (bottom) (A) Feedback Voltage (middle) (V) Typical Characteristics Time (200ns/div) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Transition of LED Current (10 White LEDs; SEL = Low; ILED = 13mA to 6mA) 34 32 30 28 0.4 0.3 0.2 0.1 34 32 30 0.4 0.3 0.2 0.1 0.0 0.0 Time (50µs/div) Time (50µs/div) Low Side Switch On Resistance VIN = 4.2V 3.6V VIN =Voltage vs. Input VIN = 2.7V 300 260 280 240 100°C 240 220 200 180 85°C 25°C 200 160 140 3.1 3.5 3.9 4.3 4.7 5.1 25°C 80 2.7 5.5 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Input Voltage (V) EN/SET Latch Timeout vs. Input Voltage EN/SET Off Timeout vs. Input Voltage 300 350 EN/SET Off Timeout (µs) EN/SET Latch Timeout (µs) 85°C 100 Input Voltage (V) 300 -40°C 250 85°C 200 25°C 150 100 2.7 100°C 180 120 160 140 2.7 120°C 220 120°C RDS(ON)L (mΩ) RDS(ON)IN (mΩ) Input Disconnect Switch Resistance VIN = 4.2V 3.6V VIN =Voltage vs. Input VIN = 2.7V 260 Feedback Voltage (bottom) (V) Output Voltage (top) (V) Transition of LED Current (10 White LEDs; SEL = Low; ILED = 3mA to 13mA) Feedback Voltage (bottom) (V) Output Voltage (top) (V) Typical Characteristics 3.1 3.5 3.9 4.3 Input Voltage (V) 4.7 5.1 -40°C 250 200 25°C 100 50 2.7 5.5 85°C 150 3.1 3.5 3.9 4.3 4.7 5.1 5.5 Input Voltage (V) Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 7 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Enable High Threshold (VIH) vs. Input Voltage Enable Low Threshold (VIL) vs. Input Voltage Enable High Threshold (VIH) (V) Enable Low Threshold (VIL) (V) Typical Characteristics 1.2 1.1 25°C 1.0 -40°C 0.9 85°C 0.8 0.7 0.6 2.7 3.1 3.5 3.9 4.3 Input Voltage (V) 4.7 5.1 5.5 1.2 1.1 1.0 -40°C 0.9 25°C 0.8 0.7 85°C 0.6 0.5 0.4 2.7 3.1 3.5 3.9 4.3 4.7 Input Voltage (V) 8 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 5.1 5.5 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Functional Block Diagram LIN PVIN VIN OVP EN/SET FB SW Reference Output Select Control SEL AGND Functional Description The AAT1239-1 consists of a DC/DC boost controller, an integrated slew rate controlled input disconnect MOSFET switch, and a high voltage MOSFET power switch. A high voltage rectifier, power inductor, output capacitor, and sense resistors are required to implement a DC/DC constant current boost converter. The input disconnect switch is activated when a valid input voltage is present and the EN/SET pin is pulled high. The slew rate control on the P-channel MOSFET ensures minimal inrush current as the output voltage is charged to the input voltage, prior to the switching of the N-channel power MOSFET. Monotonic turn-on is guaranteed by the integrated soft-start circuitry. Soft-start eliminates output voltage overshoot across the full input voltage range and all loading conditions. The maximum current through the LED string is set by the ballast resistor and the feedback voltage of the IC. The output current may be programmed by adjusting the level of the feedback reference voltage which is programmed through the S2Cwire interface. The SEL pin selects one of two feedback voltage ranges. In the AAT1239-1, the SEL function is inverted in that the FB pin voltage can be programmed from 0.4V to 0.1V with PGND a logic LOW applied to the SEL pin and 0.6V to 0.3V with a logic HIGH applied to the SEL pin. The feedback voltage can be set to any one of 16 current levels within each FB range, providing high-resolution control of the LED current, using the single-wire S2Cwire control. For some applications requiring a short duration of boosting current applying a low-to-high transition on the AAT1239-1’s SEL pin, LED current can be programmed up to 3x. The step size is determined by the programmed voltage at the FB pin where the internal default setting is 1.5x in the AAT1239-1. Control Loop The AAT1239-1 provides the benefits of current mode control with a simple hysteretic output current loop providing exceptional stability and fast response with minimal design effort. The device maintains exceptional constant current regulation, transient response, and cycle-by-cycle current limit without additional compensation components. The AAT1239-1 modulates the power MOSFET switching current to maintain the programmed FB voltage. This allows the FB voltage loop to directly program the Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 9 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs required inductor current in order to maintain the desired LED current. The switching cycle initiates when the N-channel MOSFET is turned ON and current ramps up in the inductor. The ON interval is terminated when the inductor current reaches the programmed peak current level. During the OFF interval, the input current decays until the lower threshold, or zero inductor current, is reached. The lower current is equal to the peak current minus a preset hysteresis threshold, which determines the inductor ripple current. The peak current is adjusted by the controller until the LED output current requirement is met. The magnitude of the feedback error signal determines the average input current. Therefore, the AAT1239-1 controller implements a programmed current source connected to the output capacitor, parallel with the LED string and ballast resistor. There is no right-half plane zero, and loop stability is achieved with no additional compensation components. An increase in the feedback voltage (VFB) results in an increased error signal sensed across the ballast resistor (R1). The controller responds by increasing the peak inductor current, resulting in higher average current in the inductor and LED string(s). Alternatively, when the VFB is reduced, the controller responds by decreasing the peak inductor current, resulting in lower average current in the inductor and LED string(s). Under light load conditions, the inductor OFF interval current goes below zero and the boost converter enters discontinuous mode operation. Further reduction in the load current results in a corresponding reduction in the switching frequency. The AAT1239-1 provides pulsed frequency operation which reduces switching losses and maintains high efficiency under light load conditions. Operating frequency varies with changes in the input voltage, output voltage, and inductor size. Once the boost converter has reached continuous mode, further increases in the LED current will not significantly change the operating frequency. A small 2.2µH (±20%) inductor is selected to maintain high frequency switching (up to 2MHz) and high efficiency operation for outputs up to 40V. Soft Start / Enable The input disconnect switch is activated when a valid input voltage is present and the EN/SET pin is pulled high. The slew rate control on the P-channel MOSFET ensures minimal inrush current as the output voltage is charged to the input voltage, prior to switching of the 10 N-channel power MOSFET. Monotonic turn-on is guaranteed by the built-in soft-start circuitry. Soft start eliminates output current overshoot across the full input voltage range and all loading conditions. After the soft start sequence has terminated, the initial LED current is determined by the internal, default FB voltage across the external ballast resistor at the FB pin. Additionally, the AAT1239-1 has been designed to offer the system designer two choices for the default FB voltage based on the state of the SEL pin. Changing the LED current from its initial default setting is easy by using the S2Cwire single wire serial interface; the FB voltage can be decreased (as in the AAT1239-1; see Table 2) relative to the default FB voltage. Current Limit and Over-Temperature Protection The switching of the N-channel MOSFET terminates when a current limit of 2.5A (typical) is exceeded. This minimizes power dissipation and component stresses under overload and short-circuit conditions. Switching resumes when the current decays below the current limit. Thermal protection disables the AAT1239-1 when internal dissipation becomes excessive. Thermal protection disables both MOSFETs. The junction over-temperature threshold is 140°C with 15°C of temperature hysteresis. The output voltage automatically recovers when the over-temperature fault condition is removed. Over-Voltage Protection Over-voltage protection prevents damage to the AAT1239-1 during open-circuit or high output voltage conditions. An over-voltage event is defined as a condition where the voltage on the OVP pin exceeds the overvoltage threshold limit (VOVP = 1.2V typical). When the voltage on the OVP pin has reached the threshold limit, the converter stops switching and the output voltage decays. Switching resumes when the voltage on the OVP pin drops below the lower hysteresis limit, maintaining an average output voltage between the upper and lower OVP thresholds multiplied by the resistor divider scaling factor. Under-Voltage Lockout Internal bias of all circuits is controlled via the VIN input. Under-voltage lockout (UVLO) guarantees sufficient VIN bias and proper operation of all internal circuitry prior to soft start. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Application Information Assume R3 = 12kW and VOUT(MAX) = 40V. Selecting 1% resistor for high accuracy, this results in R2 = 374kW (rounded to the nearest standard value). The minimum OVP threshold can be calculated: Over-Voltage Protection OVP Protection with Open Circuit Failure The OVP protection circuit consists of a resistor network tied from the output voltage to the OVP pin (see Figure 1). To protect the device from open circuit failure, the resistor divider can be selected such that the over-voltage threshold occurs prior to the output reaching 40V (VOUT(MAX)). The value of R3 should be selected from 10kW to 20kW to minimize losses without degrading noise immunity. R2 = R3 · VOUT(MAX) -1 VOVP = 35.4V To avoid OVP detection and subsequent reduction in the programmed output current (see following section), the maximum operating voltage should not exceed the minimum OVP set point. In some cases, this may disallow configurations with high LED forward voltage (VFLED) and/or greater than ten series white LEDs. VFLED unit-to-unit tolerance can be as high as +15% of nominal for white LED devices. AAT1239-1 R2 COUT R3 AGND R2 +1 R3 VOUT(MAX) < VOUT(OVP_MIN) VOUT OVP VOUT(OVP_MIN) = VOVP(MIN) · OVP Constant Voltage Operation Under closed loop constant current conditions, the output voltage is determined by the operating current, LED forward voltage characteristics (VFLED), quantity of series connected LEDs (N), and the feedback pin voltage (VFB). VOUT = VFB + N · VFLED 1.238V 1.142V 40 30 4 2 0 Time (4ms/div) Figure 2: Over-Voltage Protection Open Circuit Response (No LED). VIN = 4.2V VIN = 2.7V Output Voltage (middle) (V) Over Voltage Protection Pin (top) (V) Inductor Current (bottom)(A) Figure 1: Over-Voltage Protection Circuit. When the rising OVP threshold is exceeded, switching is stopped and the output voltage decays. Switching automatically restarts when the output drops below the lower OVP hysteresis voltage (100mV typical) and, as a result, the output voltage increases. The cycle repeats, maintaining an average DC output voltage proportional to the average of the rising and falling OVP levels (multiplied by the resistor divider scaling factor). High operating frequency and small output voltage ripple ensure DC current and negligible flicker in the LED string(s). The waveform in Figure 3 shows the output voltage and LED current at cold temperature with a ten series white LED string and VOVP = 40V. As shown, the output voltage rises as a result of the increased VFLED which triggers the OVP constant voltage operation. Self heating of the LEDs triggers a smooth transition back to constant current control. VIN = 3.6V Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 11 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Over-Voltage Protection Cold Temperature Apply Self-Recovery VOUT (5V/div) where: VFB(MAX) = 0.4V when SEL = Low VFB(MAX) = 0.6V when SEL = High i.e., for a maximum LED current of 20mA (SEL = High): ILED (200mA/div) RBALLAST = Figure 3: Over-Voltage Protection Constant Voltage Operation (10 White LEDs; ILED = 20mA; R2 = 12kΩ; R3 = 374kΩ). While OVP is active, the maximum LED current programming error (DILED) is proportional to voltage error across an individual LED (DVFLED). ∆VFLED = (N · VFLED(TYP) - VOUT(OVP_MIN) - VFB) N To minimize the DILED error, the minimum OVP voltage (VOUT(OVP_MIN)) may be increased, yielding a corresponding increase in the maximum OVP voltage (VOUT(OVP_MAX)). Measurements should confirm that the maximum switching node voltage (VSW(MAX)) is less than 45V under worstcase operating conditions. VSW(MAX) = VOVP(MAX) · R3 + 1 + VF + VRING R2 VFB 0.6 = = 30Ω ≈ 30.1Ω ILED(MAX) 0.020 Maximum ILED Current (mA) 30 25 20 15 10 5 LED Selection and Current Setting The AAT1239-1 is well suited for driving white LEDs with constant current. Applications include main and sub-LCD display backlighting, and color LEDs. The LED current is controlled by the FB voltage and the ballast resistor. For maximum accuracy, a 1% tolerance resistor is recommended. The ballast resistor (RBALLAST) value can be calculated as follows: RBALLAST = 12 VFB(MAX) ILED(MAX) SEL = Low 20.0 24.3 30.1 40.2 60.4 121.0 13.3 16.2 20.0 26.7 40.2 80.6 Table 1: Maximum LED Current and RBALLAST Resistor Values (1% Resistor Tolerance). Typical white LEDs are driven at maximum continuous currents of 15mA to 20mA. The maximum number of series connected LEDs is determined by the minimum OVP voltage of the boost converter (VOUT(OVP_MIN)), minus the maximum feedback voltage (VFB(MAX)) divided by the maximum LED forward voltage (VFLED(MAX)). VFLED(MAX) can be estimated from the manufacturers’ datasheet at the maximum LED operating current. VOUT(OVP_MIN) = VOVP(TYP) · VF = ‑Schottky Diode DS1 forward voltage at turn-OFF VRING = Voltage ring occurring at turn-OFF RBALLAST (W) SEL = High N= R2 +1 R3 (VOUT(OVP_MIN) - VFB(MAX)) VFLED(MAX) Figure 4 shows the schematic of using ten LEDs in series. Assume VFLED @ 20mA = 3.5V (typical) from LW M673 (OSRAM) datasheet. VOUT(OVP_MIN) = 1.2V · N= 374kΩ + 1 = 38.6V 10.4kΩ 38.6V - 0.6V 3.5V ≈ 10.9 Therefore, under these typical operating conditions, ten LEDs can be used in series. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs DS1 L1 2.2µH VCC JP1 C1 2.2µF D1 LED D6 LED R4 10K 1 2 3 Enable JP2 1 2 3 4 5 6 U1 PVIN EN SEL VIN N/C SW LIN OVP FB AGND PGND SW R2 374K 12 11 10 9 8 7 D7 LED D3 LED D8 LED R3 12K D4 LED D9 LED AAT1239-1 TSOP12JW 1 2 3 D2 LED D5 LED D10 LED R1 Select C2 2.2µF 30.1 C1 10V 0603 X5R 2.2µF GRM188R60J225KE01D C2 50V 1206 X7R 2.2µF GRM31CR71H225KA88 L1 2.2µH SD3814-2R2 or SD3110-2R2 DS1 SS16L D1-D10 LW M673 White LED other alternatives: more stability at 40V: C2 50V 1206 X7R 4.7µF GRM31CR71H475K under 20V application: C2 25V 0805 X7R 2.2µF GRM21BR71E225KA73L Figure 4: AAT1239-1 White LED Boost Converter Schematic. LED Brightness Control 25 LED Current (mA) The AAT1239-1 uses S2Cwire programming to control LED brightness and does not require PWM (pulse width modulation) or additional control circuitry. This feature greatly reduces the burden on a microcontroller or system IC to manage LED or display brightness, allowing the user to “set it and forget it.” With its high-speed serial interface (1MHz data rate), the output current of the AAT1239-1 can be changed successively to brighten or dim the LEDs in smooth transitions (i.e., to fade out) or in abrupt steps, giving the user complete programmability and real-time control of LED brightness. 20 SEL=HIGH Default 15 10 SEL=LOW 5 0 1 4 7 10 13 16 S2Cwire Data Register Figure 5: Programming AAT1239-1 LED Current with RBALLAST = 30.1W. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 13 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Alternatively, toggling the SEL logic pin from low to high implements stepped or pulsed LED currents by increasing the FB pin voltage. Figure 6 illustrates the SELECT pin scaling factor, defined as the LED current with SEL=HIGH divided by the LED current with SEL=LOW. In the AAT1239-1, the possible scaling factors are 3.0x to 1.5x with the internal default setting of 1.5x. edges of the EN/SET input and decodes them into 16 individual states. Each state corresponds to a reference feedback voltage setting on the FB pin, as shown in Table 2. S2Cwire Serial Interface Timing The S2Cwire single wire serial interface data can be clocked-in at speeds up to 1MHz. After data has been submitted, EN/SET is held high to latch the data for a period TLAT. The FB pin voltage is subsequently changed to the level as defined by the state of the SEL logic pin. When EN/SET is set low for a time greater than TOFF, the AAT1239-1 is disabled. When the AAT1239-1 is disabled, the register is reset to its default value. In the AAT1239-1, the FB pin voltage is set to 0.3V if the EN/SET pin is subsequently pulled HIGH. Select Pin Scaling Factor (Low to High) 3. 5 3. 0 2. 5 2. 0 (Default) 1. 5 1. 0 1 4 7 10 16 13 S2Cwire Feedback Voltage Programming S2Cwire Data Register The FB pin voltage is set to the default level at initial powerup. The AAT1239-1 is programmed through the S2Cwire interface. Table 2 illustrates FB pin voltage programming for the AAT1239-1. The rising clock edges applied at the EN/SET pin determine the FB pin voltage. If a logic LOW is applied at the SEL pin of the AAT1239-1, the default feedback voltage range becomes 0.4V to 0.1V and 0.6V to 0.3V for a logic HIGH condition at the SEL pin. Figure 6: AAT1239-1 SEL Pin Scaling Factor: ILED (SEL = High) Divided by ILED (SEL = Low). S2Cwire Serial Interface Skyworks’ S2Cwire single wire serial interface is a proprietary high-speed single-wire interface available only from Skyworks. The S2Cwire interface records rising THI TLO TOFF T LAT EN/SET 1 Data Reg 2 n-1 0 n ≤ 16 n 0 Figure 7: AAT1239-1 S2Cwire Timing Diagram to Program the Output Voltage. 14 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs SEL = Low SEL = High Rising Clock Edges/Data Register Reference Voltage (V) LED Current (mA); RBALLAST = 30.1W Reference Voltage (V) LED Current (mA); RBALLAST = 30.1W 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 0.4 (default) 0.38 0.36 0.34 0.32 0.30 0.28 0.26 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 13.29 12.62 11.96 11.30 10.63 9.97 9.30 8.64 7.97 7.31 6.64 5.98 5.32 4.65 3.99 3.32 0.6 (default) 0.58 0.56 0.54 0.52 0.50 0.48 0.46 0.44 0.42 0.40 0.38 0.36 0.34 0.32 0.30 19.93 19.27 18.60 17.94 17.28 16.61 15.95 15.28 14.62 13.95 13.29 12.62 11.96 11.30 10.63 9.97 Table 2: AAT1239-1 S2Cwire Reference Feedback Voltage Control Settings With RBALLAST = 30.1W (Assumes Nominal Values)*. Selecting the Schottky Diode To ensure minimum forward voltage drop and no recovery, high voltage Schottky diodes are considered the best choice for the AAT1239-1 boost converter. The output diode is sized to maintain acceptable efficiency and reasonable operating junction temperature under full load operating conditions. Forward voltage (VF) and package thermal resistance (qJA) are the dominant factors to consider in selecting a diode. The diode non-repetitive peak forward surge current rating (IFSM) should be considered for high pulsed load applications, such as camera flash. IFSM rating drops with increasing conduction period. Manufacturers’ datasheets should be consulted to verify reliability under peak loading conditions. The diode’s published current rating may not reflect actual operating conditions and should be used only as a comparative measure between similarly rated devices. 40V rated Schottky diodes are recommended for outputs less than 30V, while 60V rated Schottky diodes are recommended for outputs greater than 35V. The switching period is divided between ON and OFF time intervals. 1 = TON + TOFF FS During the ON time, the N-channel power MOSFET is conducting and storing energy in the boost inductor. During the OFF time, the N-channel power MOSFET is not conducting. Stored energy is transferred from the input battery and boost inductor to the output load through the output diode. Duty cycle is defined as the ON time divided by the total switching interval. D= TON TON + TOFF = TON ⋅ FS *All table entries are preliminary and subject to change without notice. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 15 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs The maximum duty cycle can be estimated from the relationship for a continuous mode boost converter. Maximum duty cycle (DMAX) is the duty cycle at minimum input voltage (VIN(MIN)). high efficiency under light load. The rectifier reverse current increases dramatically at elevated temperatures. Selecting the Boost Inductor The AAT1239-1 controller utilizes hysteretic control and the switching frequency varies with output load and input voltage. The value of the inductor determines the maximum switching frequency of the boost converter. Increased output inductance decreases the switching frequency and switching loss, but results in higher peak currents and increased output voltage ripple. To maintain 2MHz maximum switching frequency and stable operation, an output inductor sized from 1.5µH to 2.7µH is recommended. For higher efficiency in Li-ion battery applications (VIN from 3.0V to 4.2V) and stable operation, increasing the inductor size up to 10μH is recommended. Figure 15 and 16 show the special enhanced efficiency application. V - VIN(MIN) DMAX = OUT VOUT The average diode current is equal to the output current. IAVG(TOT) = IOUT The average output current multiplied by the forward diode voltage determines the loss of the output diode. PLOSS(DIODE) = IAVG(TOT) · VF A better estimate of DMAX is possible once VF is known. = IOUT · VF For continuous LED currents, the diode junction temperature can be estimated. DMAX = TJ(DIODE) = TAMB + θJA · PLOSS(DIODE) Where VF is the Schottky diode forward voltage. If not known, it can be estimated at 0.5V. Output diode junction temperature should be maintained below 110ºC, but may vary depending on application and/or system guidelines. The diode qJA can be minimized with additional PCB area on the cathode. PCB heat-sinking the anode may degrade EMI performance. The reverse leakage current of the rectifier must be considered to maintain low quiescent (input) current and Part Number Manufacturer Taiwan Semiconductor Co., Ltd. Diodes, Inc Zetex Rated Forward Current (A) (VOUT + VF - VIN(MIN)) (VOUT + VF) Manufacturer’s specifications list both the inductor DC current rating, which is a thermal limitation, and peak inductor current rating, which is determined by the saturation characteristics. Measurements at full load and high ambient temperature should be completed to ensure that the inductor does not saturate or exhibit excessive temperature rise. Non-Repetitive Peak Surge Current (A) Rated Voltage (V) Thermal Resistance (qJA, °C/W) Size (mm) (LxWxH) Case 60 50 40 45 45 45 3.8x1.9x1.43 3.8x1.9x1.43 3.8x1.9x1.43 Sub SMA Sub SMA Sub SMA SS16L SS15L SS14L 1.1 30 30 30 B340LA 3 70.0 40 25 5.59x2.92x2.30 SMA ZHCS350 0.35 4.2 40 330 1.7x0.9x0.8 SOD523 Table 3: Typical Surface Mount Schottky Rectifiers for Various Output Levels. 16 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs The output inductor (L) is selected to avoid saturation at minimum input voltage, maximum output load conditions. Peak current may be estimated using the following equation, assuming continuous conduction mode. Worst-case peak current occurs at minimum input voltage (maximum duty cycle) and maximum load. Switching frequency (FS) can be estimated from the curves and assumes a 2.2µH inductor. IPEAK = IOUT D · VIN(MIN) + MAX (1 - DMAX) (2 · FS · L) At light load and low output voltage, the controller reduces the operating frequency to maintain maximum operating efficiency. As a result, further reduction in output load does not reduce the peak current. Minimum peak current can be estimated from 0.5A to 0.75A. At high load and high output voltages, the switching frequency is somewhat diminished, resulting in higher IPEAK. Bench measurements are recommended to confirm actual IPEAK and ensure that the inductor does not saturate at maximum LED current and minimum input voltage. The RMS current flowing through the boost inductor is equal to the DC plus AC ripple components. Under worst-case RMS conditions, the current waveform is critically continuous. The resulting RMS calculation yields worst-case inductor loss. The RMS current value Manufacturer Sumida www.sumida.com Cooper Electronics www.cooperet.com Taiyo Yuden www.t-yuden.com should be compared against the manufacturer’s temperature rise, or thermal derating, guidelines. IRMS = IPEAK 3 For a given inductor type, smaller inductor size leads to an increase in DCR winding resistance and, in most cases, increased thermal impedance. Winding resistance degrades boost converter efficiency and increases the inductor’s operating temperature. PLOSS(INDUCTOR) = IRMS2 · DCR To ensure high reliability, the inductor case temperature should not exceed 100ºC. In some cases, PCB heatsinking applied to the LIN node (non-switching) can improve the inductor’s thermal capability. PCB heatsinking may degrade EMI performance when applied to the SW node (switching) of the AAT1239-1. Shielded inductors provide decreased EMI and may be required in noise sensitive applications. Unshielded chip inductors provide significant space savings at a reduced cost compared to shielded (wound and gapped) inductors. In general, chip-type inductors have increased winding resistance (DCR) when compared to shielded, wound varieties. Part Number Inductance (µH) Maximum DC ISAT Current (mA) DCR (mW) Size (mm) LxWxH Type CDRH2D14-2R2 CDRH2D14-4R7 CDRH4D22/HP-4R7 CDRH3D18-100NC SD3814-2R2 SD3110-2R2 SD3118-4R7 SD3118-100 NP03SB-2R0M NR3010T-2R2M NP03SB4R7 NP03SB100M 2.2 4.7 4.7 10 2.2 2.2 4.7 10 2 2.2 4.7 10 1500 1000 2200 900 1900 910 1020 900 1900 1100 1200 800 75 135 66 164 77 161 162 295 32 95 47 100 3.2x3.2x1.55 3.2x3.2x1.55 5.0x5.0x2.4 4.0x4.0x2.0 4.0x4.0x1.0 3.1x3.1x1.0 3.1x3.1x1.8 3.1x3.1x1.8 4.0x4.0x1.8 3.0x3.0x1.0 4.0x4.0x1.8 4.0x4.0x1.8 Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Shielded Table 4: Recommended Inductors for Various Output Levels (Select IPEAK < ISAT). Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 17 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Inductor Efficiency Considerations The efficiency for different inductors is shown in Figure 8 for ten white LEDs in series. Smaller inductors yield increased DCR and reduced operating efficiency. 75 Efficiency (%) CDRH5D16F-2R2 (29mΩ) 72 SD3814-2R2 (77mΩ) 69 66 63 2 5 8 11 14 20 17 LED Current (mA) recommended to ensure good capacitance stability over the full operating temperature range. The output capacitor is sized to maintain the output load without significant voltage droop (DVOUT) during the power switch ON interval, when the output diode is not conducting. A ceramic output capacitor from 2.2µF to 4.7µF is recommended (see Table 5). Typically, 50V rated capacitors are required for the 40V maximum boost output. Ceramic capacitors sized as small as 0805 or 1206 are available which meet these requirements. MLC capacitors exhibit significant capacitance reduction with applied voltage. Output ripple measurements should confirm that output voltage droop and operating stability are acceptable. Voltage derating can minimize this factor, but results may vary with package size and among specific manufacturers. Output capacitor size can be estimated at a switching frequency (FS) of 500kHz (worst case). Figure 8: AAT1239-1 Efficiency for Different Inductor Types (VIN = 3.6V; Ten White LEDs in Series). COUT = Selecting the Boost Capacitors IOUT · DMAX FS · ∆VOUT The high output ripple inherent in the boost converter necessitates low impedance output filtering. To maintain stable operation at full load, the output capacitor should be sized to maintain DVOUT between 100mV and 200mV. Multi-layer ceramic (MLC) capacitors provide small size and adequate capacitance, low parasitic equivalent series resistance (ESR) and equivalent series inductance (ESL), and are well suited for use with the AAT1239-1 boost regulator. MLC capacitors of type X7R or X5R are The boost converter input current flows during both ON and OFF switching intervals. The input ripple current is less than the output ripple and, as a result, less input capacitance is required. Manufacturer Part Number Value (µF) Voltage Rating Temp Co Case Size Murata Murata Murata Murata Murata GRM188R60J225KE19 GRM188R61A225KE34 GRM21BR71E225KA73L GRM31CR71H225KA88 GRM31CR71H475K 2.2 2.2 2.2 2.2 4.7 6.3 10 25 50 50 X5R X5R X7R X7R X7R 0603 0603 0805 1206 1206 Table 5: Recommended Ceramic Capacitors. 18 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs PCB Layout Guidelines Boost converter performance can be adversely affected by poor layout. Possible impact includes high input and output voltage ripple, poor EMI performance, and reduced operating efficiency. Every attempt should be made to optimize the layout in order to minimize parasitic PCB effects (stray resistance, capacitance, and inductance) and EMI coupling from the high frequency SW node. A suggested PCB layout for the AAT1239-1 boost converter is shown in Figures 9 and 10. The following PCB layout guidelines should be considered: 1. Minimize the distance from Capacitor C1 and C2 negative terminal to the PGND pins. This is especially true with output capacitor C2, which conducts high ripple current from the output diode back to the PGND pins. 2. Minimize the distance between L1 to DS1 and switching pin SW; minimize the size of the PCB area connected to the SW pin. 3. Maintain a ground plane and connect to the IC PGND pin(s) as well as the GND terminals of C1 and C2. 4. Consider additional PCB area on DS1 cathode to maximize heatsinking capability. This may be necessary when using a diode with a high VF and/or thermal resistance. 5. To avoid problems at startup, add a 10kW resistor between the VIN, VP and EN/SET pins (R4). This is critical in applications requiring immunity from input noise during “hot plug” events, e.g. when plugged into an active USB port. Figure 9: AAT1239-1 Evaluation Board Top Side Layout (with ten LEDs and microcontroller). Figure 10: AAT1239-1 Evaluation Board Bottom Side Layout (with ten LEDs and microcontroller). Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 19 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs S2Cwire Microcontroller VCC R7 1k R8 330 D12 Red Select Down Up R6 1k R5 1k 1 2 S1 3 4 S2 U2 PIC12F675 VDD VSS GP5 GP0 GP4 GP1 GP3 GP2 8 C3 0.1µF 7 6 R9 330 5 S3 D11 Green JP2 JP3 R4 10k DCC 10µF DC+ VCC 1 2 3 1 U1 AAT1239-1 PVIN EN 3 SEL JP1 2 4 C1 4.7µF 5 6 L1 10µH DS1 Schottky LIN 11 OVP 10 FB R3 12k 9 VIN N/C AGND 8 PGND SW SW VOUT R2 374k 12 AAT1239-1 White LED Driver JP4 D1 WLED C2 2.2µF D2 WLED D3 WLED 7 D4 WLED D5 WLED R1 30.1 D10 WLED D9 WLED D8 WLED D7 D6 WLED WLED Figure 11: AAT1239-1 Evaluation Board Schematic (with ten LEDs and microcontroller). 20 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Additional Applications Efficiency vs. LED Current PVIN Li-Ion VIN = 2.7V to 5.5V C1 2.2µF VIN DS1 Schottky R2 158k LIN SW AAT1239 -1 OVP (4 White LEDs; RBALLAST = 30.1Ω) Up to 17V/ 30mA max C2 2.2µF R3 12k 84 D1 LED 83 D2 LED 82 Efficiency (%) L1 2.2µH D3 LED D4 LED PGND EN/SET SEL FB AGND R1 30.1Ω VIN = 5V 81 80 79 VIN = 3.6V VIN = 4.2V 78 77 76 20mA 75 74 2 4 6 8 10 12 14 16 18 20 18 20 18 20 ILED (mA) Figure 12: Four LEDs In Series Configuration. Efficiency vs. LED Current Li-Ion VIN = 2.7V to 5.5V C1 2.2µF PVIN LIN VIN SW AAT1239-1 DS1 Schottky R2 287k C2 2.2µF SEL D3 LED D5 LED FB AGND R1 30.1Ω D8 LED 20mA D7 LED VIN = 5V 78 D2 LED D4 LED PGND EN/SET 80 D1 LED R3 12k OVP (8 White LEDs; RBALLAST = 30.1Ω) Up to 30V/ 30mA max Efficiency (%) L1 2.2µH D6 LED 76 74 72 VIN = 3.6V VIN = 4.2V 70 68 66 2 4 6 8 10 12 14 16 ILED (mA) Figure 13: Eight LEDs In Series Configuration. Efficiency vs. LED Current PVIN Li-Ion VIN = 2.7 V to 5.5V C1 2.2µF VIN DS1 Schottky R2 324k LIN SW AAT1239-1 OVP SEL 78 VIN = 5V D1 LED C2 2.2µF R3 12k 76 D2 LED D3 LED D4 LED PGND EN/SET (9 White LEDs; RBALLAST = 30.1Ω) Up to 34V/ 30mA max Efficiency (%) L1 2.2µH D5 LED FB AGND R1 30.1Ω 20mA D9 LED D8 LED D7 LED D6 LED 74 72 VIN = 4.2V VIN = 3.6V 70 68 66 2 4 6 8 10 12 14 16 ILED (mA) Figure 14: Nine LEDs In Series Configuration. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 21 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs 90.0 L1 10μH C1 4.7μF VIN R2 374kΩ LIN AAT1239-1 SW R3 12kΩ OVP PGND D1 C2 2.2μF Efficiency (%) PVIN Li-Ion VIN = 3.0V to 4.2V 87.5 DS1 D2 D3 D4 D5 D6 EN/SET FB SEL R1 30.1Ω AGND D10 D9 D8 D7 20mA 85.0 82.5 80.0 77.5 75.0 VIN = 3.0V VIN = 3.6V VIN = 4.2V 72.5 C1 10V 0805 X5R 4.7μF GRM219R61A475KE19 C2 50V 1206 X7R 2.2μF GRM31CR71H225KA88 L1 10μH CDRH3D18-100NC DS1 SS16L 70.0 2 4 6 8 10 12 14 16 18 20 IOUT (mA) Figure 15: Enhanced Efficiency Configuration for Li-ion Battery Ten WLEDs Series-Connected Application. 85.0 L1 4.7μH C1 4.7μF LIN VIN SW R3 12kΩ AAT1239 -1 OVP PGND EN/SET SEL C1 10V 0805 X5R 4.7μF GRM219R61A475KE19 C2 50V 1206 X7R 2.2μF GRM31CR71H225KA88 L1 4.7μH CDRH4D22/HP-4R7 DS1 SS16L FB AGND 82.5 R2 374kΩ R1 15Ω 40mA C2 2.2μF D1 D11 Efficiency (%) Li-Ion VIN=3.0V to 4.2V PVIN DS1 80.0 D2 D12 D3 D13 D4 D14 D5 D15 D6 D16 D7 D17 D8 D18 67.5 D9 D19 65.0 D10 D20 77.5 75.0 72.5 VIN = 3.0V VIN = 3.6V VIN = 4.2V 70.0 5 10 15 20 25 30 IOUT (mA) Figure 16: Enhanced Efficiency Configuration for Li-ion Battery, Two Branch, Ten WLEDs Series-Connected Application. 22 Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 35 40 DATA SHEET AAT1239-1 40V Step-Up Converter for Four to Ten White LEDs Ordering Information Package Marking1 Part Number (Tape and Reel)2 TSOPJW-12 ZLXYY AAT1239ITP-1-T1 Skyworks Green™ products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of Green™, document number SQ04-0074. Package Information TSOPJW-12 2.85 ± 0.20 2.40 ± 0.10 + 0.10 0.20 - 0.05 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 7° NOM 0.055 ± 0.045 0.04 REF 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 generally held on part numbers listed in BOLD. Copyright © 2012 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes. No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale. THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale. Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters. Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference. Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com 202112B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • August 20, 2012 23