AME AME5142/5142A/5142B n General Description The AME5142/5142A/5142B is a Boost DC/DC converter specifically designed to drive white LEDs with a constant current. The device can drive 1 to 6 LEDs in series or multiple strings from a Li-lon cell. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The AME5142/5142A/5142B switches at 1.2MHz, allowing the use of tiny external components. The input and output capacitor can be as small as 1µF(or 4.7µF), saving space and cost versus alternative solutions. A low feedback voltage minimizes power loss in the current setting resistor for better efficiency. The AME5142/5142A/5142B is available in SOT-26/TSOT-26 & SOT-25/TSOT-25 packages. The only difference between AME5142, AME5142A and AME5142B is feedback trip point. The AME5142 is 0.15V and AME5142A/5142B is 0.104V. n Features l 1.2MHz Fixed Switching Frequency High Efficiency 6 White LED Driver With Open LED Protection n Typical Application L1 10µH VIN 2.7V to 5.5V CIN 4.7µF VOUT IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP GND FB R1 7.5Ω Figure 1: Circuit For Driving 2 White LEDs L1 10µH VIN 2.7V to 5.5V CIN 4.7µF VOUT IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP l 28V Over Voltage Protection l Over Temperature Protection l Under Voltage Lockout Protection GND l Internal Soft Start FB R1 7.5Ω l 30V Internal Switch l Drives Up to 6 LEDs from a 2.7V Supply at 20mA l Only small external Capacitors and Inductor Figure 2: Circuit For Driving 4 White LEDs required l Cycle-by-Cycle Current Limiting l Up to 88% Efficiency l Meet RoHS Standards n Applications l LCD Bias l Hand-held Computers l Battery Backup l Digital Cameras l Personal Navigation Device L1 10µH VIN 2.7V to 5.5V CIN 4.7µF VOUT IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP GND FB R1 7.5Ω l Digital Picture Frame l Smart Phone Rev. C.02 Figure 3: Circuit For Driving 6 White LEDs 1 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection Function Block Diagram EN SW OVP SHUTDOWN CIRCUITRY IN Vref Vref 1.25V UVLO OTP R + R 0.15V * RAMP GENERATOR + R GM Q S - FB DRIVER Rc Oscillator MS CURRENT LIMIT COMP + Soft Start MS1 Cc GND * AME5142 feedback trip point is 0.15V. AME5142A and AME5142B feedback trip point is 0.104V. Figure 4 : AME5142/5142A/5142B Block Diagram 2 Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Pin Configuration SOT-25/TSOT-25 Top View 5 4 SOT-26/TSOT-26 (Recommend) Top View AME5142AEEV 6 5 4 AME5142AAEEV AME5142 AME5142A AME5142AAEEY AME5142BAEEY AME5142 AME5142A AME5142B 1. SW 2. GND 1. SW 2. GND 3. FB 1 2 3 4. EN AME5142AEEY 3. FB 1 2 3 5. IN 4. EN 5. OVP 6. IN (Recommend) Die Attach: Die Attach: Conductive Epoxy Conductive Epoxy n Pin Description AME5142AEEV/AME5142AAEEV Pin Number Pin Name Pin Description 1 SW Power Switch input. This is the drain of the internal NMOS power switch. Minimize the metal trace area connected to this pin to minimize EMI. 2 GND Ground. Tie directly to ground plane. 3 FB Output voltage feedback input. Connect the ground of the feedback network to an AGND (Analog Ground) plane which should be tied directly to the GND pin. 4 EN Enable control input, active high. The enable pin is an active high control. Tie this pin above 1.5V to enable the device. Tie this pin below 0.4V to turn off the device. 5 IN Analog and Power input. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible. Rev. C.02 3 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection n Pin Description AME5142AEEY/AME5142AAEEY/AME5142BAEEY (Recommend) 4 Pin Number Pin Name Pin Description 1 SW Power Switch input. This is the drain of the internal NMOS power switch. Minimize the metal trace area connected to this pin to minimize EMI. 2 GND Ground. Tie directly to ground plane. 3 FB Output voltage feedback input. Connect the ground of the feedback network to an AGND(Analog Ground) plane which should be tied directly to the GND pin. 4 EN Enable control input, active high. The enable pin is an active high control. Tie this pin above 1.5V to enable the device. Tie this pin below 0.4V to turn off the device. 5 OVP 6 IN Over Voltage Protection. Analog and Power input. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible. Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Ordering Information AME5142 x x x x xxx x Special Feature Output Voltage Number of Pins Package Type Operating Ambient Temperature Range Pin Configuration Pin Configuration A (SOT-25) (TSOT-25) A (SOT-26) (TSOT-26) Rev. C.02 1. SW 2. GND 3. FB 4. EN 5. IN Operating Ambient Temperature Range Package Type E: -40OC to +85OC E: SOT-2X Number of Pins V: 5 Y: 6 Output Voltage Special Feature ADJ: Adjustable Y: Lead free & Low profile Z: Lead free 1. SW 2. GND 3. FB 4. EN 5. OVP 6. IN 5 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Ordering Information AME5142A x x x x xxx x Special Feature Output Voltage Number of Pins Package Type Operating Ambient Temperature Range Pin Configuration Note 1. Note 1. AME5142 feedback trip point is 0.15V. AME5142A feedback trip point is 0.104V. Pin Configuration A (SOT-25) (TSOT-25) A (SOT-26) (TSOT-26) 6 1. SW 2. GND 3. FB 4. EN 5. IN Operating Ambient Temperature Range Package Type E: -40OC to +85OC E: SOT-2X Number of Pins V: 5 Y: 6 Output Voltage Special Feature ADJ: Adjustable Y: Lead free & Low profile Z: Lead free 1. SW 2. GND 3. FB 4. EN 5. OVP 6. IN Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Ordering Information AME5142B x x x x xxx x Special Feature Output Voltage Number of Pins Package Type Operating Ambient Temperature Range Pin Configuration Note 2. Note 2. AME5142 feedback trip point is 0.15V. AME5142A and AME5142B feedback trip point is 0.104V. The only difference between AME5142A and AME5142B is the behavior of OVP. Please refer to Output Over-Voltage Protection. Pin Configuration A (SOT-26) Rev. C.02 1. SW 2. GND 3. FB 4. EN 5. OVP 6. IN Operating Ambient Temperature Range Package Type E: -40OC to +85OC E: SOT-2X Number of Pins Y: 6 Output Voltage ADJ: Adjustable Special Feature Z: Lead free 7 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection n Ordering Information Part Number Marking* Output Voltage Package Operating Ambient Temperature Range AME5142AEEYADJZ BJGww ADJ SOT-26 -40OC to +85OC AME5142AEEYADJY BJGww ADJ TSOT-26 -40OC to +85OC AME5142AEEVADJZ BJHww ADJ SOT-25 -40OC to +85OC AME5142AEEVADJY BJHww ADJ TSOT-25 -40OC to +85OC AME5142AAEEYADJZ BVKww ADJ SOT-26 -40OC to +85OC AME5142AAEEYADJY BVKww ADJ TSOT-26 -40OC to +85OC AME5142BAEEYADJZ BYPww ADJ SOT-26 -40OC to +85OC AME5142BAEEYADJY BYPww ADJ TSOT-26 -40OC to +85OC AME5142AAEEVADJZ BVLww ADJ SOT-25 -40OC to +85OC AME5142AAEEVADJY BVLww ADJ TSOT-25 -40OC to +85OC Note: ww represents the date code and pls refer to Date Code Rule page on Package Dimension. * A line on top of the first letter represents lead free plating such as BJGww. Please consult AME sales office or authorized Rep./Distributor for the availability of package type. 8 Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Absolute Maximum Ratings Parameter Symbol Maximum Unit VIN 6 V VEN ,VFB VIN V VSW,VOVP 30 V Input Supply Voltage EN, FB Voltages SW, OVP Voltage B* ESD Classification Caution: Stress above the listed in absolute maximum ratings may cause permanent damage to the device. * HBM B: 2000V ~ 3999V n Recommended Operating Conditions Parameter Symbol Rating Ambient Temperature Range TA -40 to +85 Junction Temperature Range TJ -40 to +125 Storage Temperature Range TSTG -65 to +150 Unit o C n Thermal Information Parameter Thermal Resistance* (Junction to Case) Thermal Resistance (Junction to Ambient) Package SOT-25 TSOT-25 SOT-26 TSOT-26 Die Attach Symbol Maximum θJC 81 Unit o C/W Conductive Epoxy Internal Power Dissipation Solder Iron (10Sec)** θJA 260 PD 400 350 mW o C * Measure θJC on center of molding compound if IC has no tab. ** MIL-STD-202G 210F Rev. C.02 9 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Electrical Specifications VIN = 4.2V, EN = VIN, TA = 25oC, Unless otherwise noted. Parameter Input Voltage Quiescent Current Symbol Test Condition VIN IQ Min Typ 2.7 Max Units 5.5 V Switching, VFB = 0V 0.85 1 mA Not Switching, VFB = 0.2V 180 250 µA Feedback Trip Point (AME5142) VFB 0.137 0.15 0.163 V Feedback Trip Point (AME5142A/5142B) VFB 0.094 0.104 0.114 V FB Pin Bias Current IFB 0.1 1 µA Switch Current Limit ICL 850 1000 mA 0.7 1.4 Ω 1 10 µA 1.5 MHz Switch On-Resistance RDSON VFB = 0.2V 650 ISW = 100mA, VFB = 0.2V SW Leakage Current ISW VSW = 20V Swich frequency fSW VFB = 0.1V 0.9 1.2 Dmax VFB = 0V 88 92 ISD VEN = 0V 0.01 OTP Shutdown, temperature increasing 160 TRS Restore, temperature decreasing 140 Maximum Duty Cycle Shutdown Supply Current % 1 o Over Temperature Protection Over Voltage Protection (AME5142) 10 OVP Rising edge Over Voltage Protection (AME5142A/5142B) OVP Rising edge Input Undervoltage Lockout UVP VIN rising or falling EN Input Low VEL EN Input High VEH EN Input Current IEN 24 26 µA C 28 V 26 28 30 2.35 2.5 2.65 V 0.4 V 1.5 EN = GND or VIN 0.1 2 µA Rev. C.02 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection n Detailed Description n Application Information The AME5142/5142A/5142B is a constant frequency step-up converter with an internal switch. The operations of AME5142/5142A/5142B can be understood from block diagram clearly figure.2. The oscillator triggers the SET input of SR latch to turn on the power switch MS at the start of each cycle. A current sense voltage sum with a stabilizing ramp is connected to the positive terminal of the PWM comparator. When this voltage exceeds the output voltage of the error amplifier, the SR latch is reset to turn off the power switch till next cycle starts. The output voltage of the error amplifier is amplified from the difference between the reference voltage 0.15V and the feedback voltage. In this manner, if the error amplifiers voltage increases, more current is delivered to the output; if it decreases, less current is delivered. A 28V Zener diode connects from OVP pin to FB pin internally to provide an optional protection function which prevents SW pin from over-voltage damage. Especially when the case of the feedback loop broken due to component wear-out or improper connection occurs. Inductor Selection Current Limit Protection Schottky diode is a good choice for AME5142/5142A/ 5142B because of its lower forward voltage drop and faster reverse recovery. Using schottky diode can get better efficiency. The high speed rectification is also a good characteristic of schottky diode for high switching frequency. Current rating of the diode must meet the root mean square of the peak current and output average current multiplication. The AME5142/5142A/5142B has current limiting protection to prevent excessive stress on itself and external components during overload conditions. The internal current limit comparator will disable the NMOS power device at a typical switch peak current limit of 850mA. Output Over-Voltage Protection The AME5142/5142A/5142B contains dedicated circuitry for monitoring the output voltage. In the event that the primary LED network is disconnected the output will increase and be limited to 28V (TYP), which will turn the NMOS off when the output voltage is at 28V (max.) until the output voltage reach 28V (TYP.) or lower. The 28V limit allows the use of 28V 1µF ceramic output capacitors creating an overall small solution for white LED applications. If the output ever exceeds OVP, the AME5142B will shut down. AME5142B will not switch again until the power is recycled. If the output exceeds OVP, the OVP of AME5142/5142A is to clamp the output voltage to 28V typically. The recommended value of inductor for AME5142/ 5142A/5142B applications is 10µH. Small size and better efficiency are the major concerns for portable device, such as AME5142/5142A/5142B used for dual panel mobile phone. The inductor should have low DCR for better efficiency. To avoid inductor saturation, current rating should be at least 1A. The input range is 2.7V to 5.5V. Capacitor Selection 4.7µF input capacitor can reduce input ripple. For better voltage stability, to increase the input capacitor value or using LC filter is feasible, especially in the Li-ion battery application. 1µF output capacitor is sufficient to reduce output voltage ripple. For better voltage filtering, ceramic capacitors with low ESR are recommended. X5R and X7R types are suitable because of their wider voltage and temperature ranges. Diode Selection Duty Cycle The maximum duty cycle of the switching regulator determines the maximum boost ratio of output-toinput voltage that the converter can attain in mode of operation. The duty cycle for a given boost application is defined as: This applies for continuous mode operation. D= VOUT + VDIODE - V IN VOUT + VDIODE - VSW Under Voltage Protection The AME5142/5142A/5142B has an UVP comparator to turn the NMOS power device off in case the input voltage or battery voltage is too low preventing an on state of the power device conducting large amounts of current. Rev. C.02 11 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Calculating Load Current The load current is related to the average inductor current by the relation: ILOAD = IIND (AVG) x (1 - D) Where “ D” is the duty cycle of the application. The switch current can be found by: ISW = IIND (AVG) + 1 /2 (IRIPPLE) Inductor ripple current is dependent on inductance, duty cycle, input voltage and frequency: IRIPPLE = D x (V IN-V SW) / (f x L) Combining all terms, we can develop an expression which allows the maximum available load current to be calculated: I LOAD ( 1-D ) x ( ICL (max) - D ( VIN -V SW ) ) 2fL Thermal Considerations At higher duty cycles, the increased ON time of the FET means the maximum output current will be determined by power dissipation within the AME5142/5142A/5142B switch. The switch power dissipation from ON-state conduction is calculated by: P(SW) = D x IIND(AVE)2 x RDS(ON) There will be some switching losses as well, so some derating needs to be applied when calculating IC power dissipation. Shutdown Pin Operation The device is turned off by pulling the shutdown pin low. If this function is not going to be used, the pin should be tied directly to VIN. If the SHDN function will be needed, a pull-up resistor must be used to VIN (approximately 50k-100k recommended). The EN pin must not be left unterminated. 12 Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Evaluation Board Schematic VDD D1 L1 VLED_Anod 4.7uH 1A 30V_1A C1 C2 U1 6 Enable R1 4 2 IN SW EN OVP GND FB CF 1 5 VLED_cathode 3 AME5142AEEYADJZ R2 Bill Of Materials Location Value Description Part Num. Manufacture Package C1 6.3V/4.7uF Ceramic Capacitor C1608Y5V0J475ZT TDK 1608 C7 25V/1uF Ceramic Capacitor C2012X7R1E105KT TDK 2012 R1 51KΩ Chip Resistor FCR05-F-T-5102 PDC 805 R5 7.5Ω Chip Resistor FCR05-F-T-0750 PDC 805 R3 16.9KΩ Chip Resistor FCR05-F-T-1692 PDC 805 L1 4.7uH Inductor CDRH3D14/HP-4R7 Sumida D1 30V/1A Schottky Rectifier B130 Any Rev. C.02 SMA 13 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Operating Instructions 1. Connect VDD to the power source’ s positive output. 2. Connect GND to supply ground. 3. Applying a logic signal to EN pin will enable the AME5142. Logic high (V EN>1.5V) turns on AME5142, logic low puts it into low current shutdown mode. Application Information Setting Output Current The regulated output current is set with an external resistor divider (R5 in Figure 1.) from the output to the VFB pin and is determined by: I OUT = VFB R5 To prevent stray capacitance and noises, locate resistors R5 close to AME5142. The external resistor sets the output current table as below : 14 I OUT R5 20mA 7.5Ω 40mA 3.75Ω 60mA 2.5Ω 80mA 1.875Ω Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Board Layout Consideration High frequency switching regulators require very careful layout of components in order to get stable operation and low noise. A good PCB layout could make AME5142 work its best performance. PCB Layout Example The PCB layout example of AME5142 for six strings of LEDs to be driven in one parallel application. The placements is suitable and smooth, and follows the layout guide lines. 1. Use a ground plane under the switching regulator to minimize inter-plane coupling. 2. Using 20mil wide track for GND (as wide as possible), and all GND nodes are as close as possible. 3. The SW node, schottky diode and output capacitor C2 signal path should be kept extremely short. 4. The feedback components R1,R2 and CF must be kept close to the FB pin of U1 to prevent noise injection on the FB pin trace and keeping faraway from SW node. VLED _Anode SW D1 Vout GND SW IN L1 IN C1 U1 Vout 1 SW 6 IN GND 2 GND 5 OVP 3 4 C2 CF Vo VLED _Cathode Rev. C.02 FB FB EN EN FB GND R2 EN Enable R1 15 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Dimming Control A. Using a PWM Signal to EN Pin For controlling the LED brightness, the AME5142/5142A/5142B can perform the dimming control by applying a PWM signal to EN pin. The average LED current is proportional to the PWM signal duty cycle. The magnitude of the PWM signal should be higher than the maximum enable voltage of EN pin, in order to let the dimming control perform correctly. L1 22µH VIN 3.3V CI N 4.7µF VOUT IN Dimming Control 150KHz COUT 2.2µF SW AME5142 AME5142A EN AME5142B OVP GND FB R1 7.5Ω Figure 5. PWM Dimming Control Using the EN Pin VFB VS Duty Cycle IOUT VS Duty Cycle 20 150 18 125 16 14 I OUT(mA) VFB(mV) 100 75 50 12 10 8 6 4 25 2 0 0.2 0.4 0.6 Duty Cycle 16 0.8 0 0.2 0.4 0.6 0.8 Duty Cycle Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B B. Using a DC Voltage Using a variable DC voltage to adjust the brightness is a popular method in some applications. The dimming control using a DC voltage circuit is shown in Figure 6. According to the Superposition Theorem, as the DC voltage increases, the voltage contributed to VFB increases and the voltage drop on R2 decreases, i.e. the LED current decreases. For example, if the VDC range is from 0V to 2.8V, the selection of resistors in Figure 6 sets dimming control of LED current from 20mA to 0mA. L1 10µH VIN 2.7V to 5.5V C IN 4.7µF VOUT IN COUT 1µF SW AME5142 AME5142A EN OVP AME5142B R3 5.1K FB GND R4 91K R2 7.5Ω VDC Dimming 0V to 2.8V Figure 6. Dimming Control Using a DC Voltage VFB VS VDC IOUT VS VDC 20 150 125 15 IOUT(mA) VFB(mV) 100 75 10 50 5 25 0 0 0 0.56 1.12 1.68 VDC(V) Rev. C.02 2.24 2.80 0 0.56 1.12 1.68 2.24 2.80 VDC(V) 17 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B C. Using a Filtered PWM Signal The filtered PWM signal can be considered as an adjustable DC voltage. It can be used to replace the variable DC voltage source in dimming control. The circuit is shown in Figure 7. L1 10µH VIN 2.7V to 5.5V C IN 4.7µF VOUT IN COUT 1µF SW AME5142 AME5142A EN OVP AME5142B R3 5.1K FB GND R4 91K R2 7.5Ω CDC 1µF R DC 10K 2.8V 0V PWM Signal 20KHZ Figure 7. Dimming Control Using a Filtered PWM Signal IOUT VS Duty Cycle VFB VS Duty Cycle 20 150 125 15 IOUT(mA) VFB(mV) 100 75 10 50 5 25 0 0 0 0.2 0.4 0.6 Duty Cycle 18 0.8 1 0 0.2 0.4 0.6 0.8 1 Duty Cycle Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Typical Operating Characteristics L1 10µH VIN 2.7V to 5.5V CIN 4.7µF Efficiency Vs IOUT VOUT IN 90 COUT 1µF SW 85 GND Efficiency (%) AME5142 AME5142A EN OVP AME5142B FB R2 7.5Ω VIN = 3.6V VIN = 4.2V 80 VIN = 3.3V 75 VIN = 2.7V 70 65 60 I LED = 20mA 55 Figure 8: Circuit For Driving 6 White LEDs V OUT =18.6V 50 0 5 10 15 20 IOUT(mA) L1 10µH VIN 3.3V to 5.5V CIN 4.7µF Efficiency Vs VIN VOUT IN 100 C OUT 1µF SW AME5142 AME5142A EN AME5142B OVP Efficiency (%) GND 95 FB R2 7.5Ω R2 7.5Ω 90 85 I OUT = 40mA VOUT = 9.3V 80 Figure 9: Circuit For Driving 2 Strings of 3 White LEDs 3 3.5 4 4.5 5 5.5 VIN(v) L1 10µH VIN 3.3V to 5.5V 90 IN C OUT 1µF SW AME5142 AME5142A EN AME5142B OVP GND FB R2 7.5Ω R2 7.5Ω 85 Efficiency (%) CIN 4.7µF Efficiency Vs IOUT VOUT VIN = 3.3V 80 75 VIN = 3.6V 70 65 60 VIN = 4. 2V I LED = 20mA 55 Figure 10: Circuit For Driving 2 Strings of 3 White LEDs 50 0 V OUT = 9.3V 10 20 30 40 I OUT (mA) Rev. C.02 19 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B L1 10µH VIN 3.3V to 5.5V CIN 4.7µF Efficiency Vs VIN VOUT IN 100 COUT 1µF SW GND Efficiency (%) AME5142 AME5142A EN AME5142BOVP FB R2 7.5Ω 95 90 85 R2 7.5Ω IOUT = 40mA VOUT = 12.5V 80 3 Figure 11: Circuit For Driving 2 Strings of 4 White LEDs 3. 5 4 4.5 5 5.5 VIN (v) L1 10µH VIN 3.3V to 5.5V CIN 4.7µF Efficiency Vs IOUT VOUT 90 IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP VIN = 3.3V 80 Efficiency (%) GND 85 FB R2 7.5Ω R2 7.5Ω 75 70 VIN = 3.6V 65 VIN = 4.2V 60 ILED = 20mA 55 VOUT =12.5V 50 Figure 12: Circuit For Driving 2 Strings of 4 White LEDs 0 10 20 30 40 IOUT (mA) L1 10µH VIN 3.3V to 5.5V IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP GND 100 Efficiency (%) CIN 4.7µF Efficiency Vs VIN VOUT FB R2 7.5Ω R2 7.5Ω 95 90 85 IOUT = 40mA VOUT = 15.6V 80 Figure 13: Circuit For Driving 2 Strings of 5 White LEDs 20 3 3.5 4 4. 5 5 5.5 VIN(v) Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B L1 10µH VIN 3.3V to 5.5V Efficiency Vs IOUT VOUT 90 CIN 4.7µF IN SW FB R2 7.5Ω R2 7.5Ω VIN = 3.3V 85 Efficiency (%) AME5142 AME5142A EN AME5142BOVP GND VIN = 3.6V COUT 1µF 80 VIN = 4.2V 75 70 65 60 ILED = 20mA 55 50 Figure 14: Circuit For Driving 2 Strings of 5 White LEDs VOUT =15.6V 0 10 20 30 40 IOUT (mA) L1 10µH VIN 3.3V to 5.5V Efficiency Vs VIN VOUT 100 CIN 4.7µF IN COUT 1µF SW GND Efficiency (%) AME5142 AME5142A EN AME5142BOVP FB R2 7.5Ω R2 7.5Ω 95 90 85 IOUT = 40mA VOUT = 18.6V 80 3 Figure 15: Circuit For Driving 2 Strings of 6 White LEDs 3.5 4 4.5 5 5.5 VI N(v) L1 10µH VIN 3.3V to 5.5V Efficiency Vs IOUT VOUT 90 IN COUT 1µF SW AME5142 AME5142A EN AME5142BOVP GND FB R2 7.5Ω R2 7.5Ω 85 VIN = 3.3V Efficiency (%) CIN 4.7µF 80 75 70 65 60 VIN = 4.2V VIN = 3.6V ILED = 20mA 55 Figure 16: Circuit For Driving 2 Strings of 6 White LEDs Rev. C.02 50 0 VOUT =18.6V 10 20 30 40 IOUT(mA) 21 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Characterization Curves 92.0 91.8 91.6 91.4 91.2 91.0 90.8 90.6 90.4 90.2 90.0 89.8 89.6 89.4 89.2 89.0 88.8 88.6 88.4 88.2 88.0 -25 Oscillator Frequency vs. Temperature 1.50 Oscillator Frequency (MHz) Max Duty Cycle (%) Max Duty Cycle vs. Temperature 0 25 50 75 o 100 125 1.45 1.40 1.35 1.30 1.25 1.20 1.15 1.10 1.05 1.00 0.95 0.90 -25 0 25 50 75 100 Temperature ( C) Temperature ( oC) Switch RDSON Efficiency vs. Load Current Dirving 3 LEDs 125 100 1.80 1.60 90 1.20 Efficiency (%) RDSON (Ω) 1.40 TA = 85oC 1.00 0.80 TA = 25oC 0.60 80 70 60 0.40 3.1 3.5 3.9 4.3 4.7 5.1 3.5 3.9 4.3 4.7 5.1 VIN (V) Efficiency vs. Load Current Dirving 4 LEDs Efficiency vs. Load Current Dirving 6 LEDs 100 100 90 90 80 70 50 2.7 3.1 VIN (V) 60 22 50 2.7 5.5 Efficiency (%) Efficiency (%) 0.20 2.7 5.5 80 70 60 3.1 3.5 3.9 4.3 VI N (V) 4.7 5.1 5.5 50 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 VIN (V) Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B Current Limit vs. VIN VFB vs. Temperature 1000 0.177 0.173 0.169 900 0.165 VFB (V) Current Limit (mA) 950 850 800 0.161 0.157 0.153 750 0.149 0.145 700 0.141 650 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 0.137 -25 25 50 75 100 125 Temperature (oC) Dimming Control for Driving 6LEDs Dimming Control for Driving 6LEDs 2 2 3 3 1 1 1mS / div Rev. C.02 0 VIN (V) 1mS / div VIN = 2.7V; 6 LEDs IOUT = 20mA VIN = 5.5V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200Hz 3) VOUT , 10V / div, DC 1) VSW= 10V / div, DC 2) EN = 1V / div, DC f = 200Hz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC 23 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection Dimming Control for Driving 6LEDs Dimming Control for Driving 6LEDs 2 2 3 3 1 1 4µS / div 4µS / div VIN = 2.7V; 6 LEDs IOUT = 20mA VIN = 5.5V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200KHz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC 2) EN = 1V / div, DC f = 200KHz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC Start-Up / Shutdown Start-Up / Shutdown 1 1 2 2 3 3 200µS / Div 24 200µS / div VIN = 2.7V; 1 LEDs IOUT = 20mA VIN = 2.7V; 6 LEDs IOUT = 20mA 1) EN = 2V/div, DC 2) Inductor Current, 100mA / div, DC 3) VOUT , 2V / div, DC 1) EN = 2V / div, DC 2) Inductor Current, 500mA / div, DC 3) VOUT , 10V / div, DC Rev. C.02 AME AME5142/5142A/5142B High Efficiency 6 White LED Driver With Open LED Protection Start-Up / Shutdown Typical Switching Waveform 1 1 2 2 3 3 1µS / div 200µS / div VIN = 5.5V; 6 LEDs IOUT = 20mA VIN = 2.7V; 6 LEDs IOUT = 20mA 1) EN = 2V / div, DC 2) Inductor Current, 500mA / div, DC 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC 2) VOUT , 20mV / div, AC 3) Input Current, 100mA / div, DC Inductor = 10µH, COUT = 1µF Typical Switching Waveform Start up into Openload AME5142B 1 1 2 3 3 2 1µS / div VIN = 5.5V; 6 LEDs IOUT = 20mA 100µS / div 1) VEN = 2V / div 2) VSW, 10V / div 3) VOUT , 10V / div 1) VSW = 10V / div, DC 2) VOUT , 20mV / div, AC 3) Input Current, 100mA / div, DC Inductor = 10µH, COUT = 1µF Rev. C.02 25 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Date Code Rule Marking Date Code Year A A A W W xxx0 A A A W W xxx1 A A A W W xxx2 A A A W W xxx3 A A A W W xxx4 A A A W W xxx5 A A A W W xxx6 A A A W W xxx7 A A A W W xxx8 A A A W W xxx9 n Tape and Reel Dimension SOT-25 P W AME AME PIN 1 Carrier Tape, Number of Components Per Reel and Reel Size 26 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size SOT-25 8.0±0.1 mm 4.0±0.1 mm 3000pcs 180±1 mm Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Tape and Reel Dimension TSOT-25 P W AME AME PIN 1 Carrier Tape, Number of Components Per Reel and Reel Size Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size TSOT-25 8.0±0.1 mm 4.0±0.1 mm 3000pcs 180±1 mm SOT-26 P W AME AME PIN 1 Carrier Tape, Number of Components Per Reel and Reel Size Rev. C.02 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size SOT-26 8.0±0.1 mm 4.0±0.1 mm 3000pcs 180±1 mm 27 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Tape and Reel Dimension TSOT-26 P W AME AME PIN 1 Carrier Tape, Number of Components Per Reel and Reel Size 28 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size TSOT-26 8.0±0.1 mm 4.0±0.1 mm 3000pcs 180±1 mm Rev. C.02 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Package Dimension SOT-25 Top View Side View SYMBOLS E H D L S1 PIN 1 MAX MIN MAX A 0.90 1.30 0.0354 0.0512 A1 0.00 0.15 0.0000 0.0059 b 0.30 0.55 0.0118 0.0217 D 2.70 3.10 0.1063 0.1220 E 1.40 1.80 0.0551 0.0709 1.90 BSC e 2.60 θ1 0 3.00 o 0.10236 0.11811 0.0146BSC o 10 0 o 10 o 0.95BSC 0.0374BSC MILLIMETERS INCHES S1 A1 A 0.07480 BSC 0.37BSC L Front View INCHES MIN H e MILLIMETERS b TSOT-25 Top View Side View SYMBOLS E H D MIN MAX MIN MAX A+A1 0.90 1.25 0.0354 0.0492 b 0.30 0.50 0.0118 0.0197 D 2.70 3.10 0.1063 0.1220 E 1.40 1.80 0.0551 0.0709 1.90 BSC e L PIN 1 S1 H 2.40 θ1 Front View 0 o 0.1181 0.0138BSC o 10 0.95BSC 0.0945 0 o 10 o 0.0374BSC A1 A S1 3.00 0.35BSC L e 0.07480 BSC b Rev. C.02 29 AME High Efficiency 6 White LED Driver With Open LED Protection AME5142/5142A/5142B n Package Dimension SOT-26 Top View Side View SYMBOLS E H D e MILLIMETERS L MIN MAX MIN MAX A 0.90 1.30 0.0354 0.0512 A1 0.00 0.15 0.0000 0.0059 b 0.30 0.55 0.0118 0.0217 D 2.70 3.10 0.1063 0.1220 E 1.40 1.80 0.0551 0.0709 1.90 BSC e PIN1 S1 H 2.60 A θ1 0.07480 BSC 3.00 0.37BSC L Front View INCHES 0 o 0.10236 0.11811 0.0146BSC 10 o 0 o 10 0.95BSC 0.0374BSC MILLIMETERS INCHES A1 S1 o b TSOT-26 Top View Side View SYMBOLS E H D e L PIN1 MIN MAX MIN MAX A+A1 0.90 1.25 0.0354 0.0492 b 0.30 0.50 0.0118 0.0197 D 2.70 3.10 0.1063 0.1220 E 1.40 1.80 0.0551 0.0709 H S1 1.90 BSC e 2.40 θ1 A 0 o 10 0.95BSC 0.0945 0.1181 0.0138BSC o 0 o 10 o 0.0374BSC A1 S1 3.00 0.35BSC L Front View 0.07480 BSC b 30 Rev. C.02 www.ame.com.tw E-Mail: [email protected] Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. AME, Inc. , April 2009 Document: 1229-DS5142/5142A/5142B-C.02 Corporate Headquarter AME, Inc. 2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989