ACE714B Step-up DC/DC Converter Backlight Driver Description The ACE714B is a fixed frequency, constant current step-up DC/DC converter ideal for driving LEDs used in backlighting applications on cellular phones, PDAs and digital cameras etc. Output voltage of up to 28V can be derived, and from a 2.5V input three white LED’s can be driven in series. Luminance of the LED’s is controlled by changing the duty cycle of a PWM signal applied to the CE pin. In addition, an internal MOSFET with an Rds-on of 0.3Ω is used. Allow profile and small board area solution can be achieved using a chip coil and an ultra small ceramic output capacitor. Features Input voltage range : 2.5V-5.5V Output voltage range : up to 28V Low 104mV feedback voltage Oscillation frequency : 1.2MHz Typical Efficiency : 88%. Control : PWM control. Stand-by Current : <1μA High Supply Capability: Deliver 10V 300mA from 3.5V supply Lx limit Current : 1.3A Application For White LED Drivers Mobil phones, PHS, PDAs, Digital still cameras Absolute Maximum Ratings Parameter Symbol Value Unit Vin Voltage VIN VSS-0.3~VSS+6 V Output Voltage VOUT VSS-0.3~VSS+30 V LX Voltage VLX VSS-0.3~VSS+30 V FB Voltage VFB VSS-0.3~VSS+6 V CE Voltage VCE VSS-0.3~+6 V OVP Voltage VOVP VSS-0.3~VSS+30 V Power Dissipation PD 600 mW Operating Junction Temperature TOPR -25 to +85 ℃ Storage Temperature Range TSTG -40 to +125 ℃ Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. VER 1.2 1 ACE714B Step-up DC/DC Converter Backlight Driver Packaging Type SOT-23-6L SOT-23-6L Description 6 1 5 2 4 Function 1 LX Switch 2 VSS Ground 3 FB Voltage Feedback 4 CE Chip Enable 5 OVP Over Voltage Protect 6 VIN Power Input 3 Ordering information ACE714B XX + H Halogen - free Pb - free GM : SOT-23-6L Functional Block Diagram VER 1.2 2 ACE714B Step-up DC/DC Converter Backlight Driver Electrical Characteristics VIN=VCE=3.7V, TA=25℃, unless otherwise specified. Symbol Parameter VFB Conditions Min Typ Max Unit FB Control Voltage 94 104 114 mV VIN Operating Voltage Range 2.5 5.5 V ISTB Stand-by Current VCE=0, VIN=5V 1 µA FOSC Oscillation Frequency IOUT=100mA 1.5 MHz MAXDTY Maximum Duty Cycle EFFI Efficiency ILIMIT LX Current Limit VOVP Overvoltage Protection RDS(ON) 1 1.2 85 92 % 88 % A LX On Resistance 1.3 20 28 300 ILVL LX Leak Current 0 VCEH CE “H” Voltage VCEL CE “L” Voltage RLED=5Ω PWM dimming frequency V mΩ 1 µA 1.5 200 V 0.4 V 200K Hz Note: 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. 2. θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of JEDEC51-3 thermal measurement standard. Pin 2 of SOT23-6 packages is the case position for θJC measurement. 3. The device is not guaranteed to function outside its operating conditions. 4. EN pin voltage must be higher than 1.5V. Typical Application Circuit VER 1.2 3 ACE714B Step-up DC/DC Converter Backlight Driver Design Specifications Input Voltage (V) Input Current (A) Output Current (A) 3.7V 0~1.5A 0.2A Test conditions 3PCS LED Series Bom List Reference Designator Description L 4.7~22uH, Inductor C1 47uH/50V,EC C2 4.7uF/25V C3, C4 10uF/50V R2 1Ω, 1%, 0603 R3 2Ω, 1%, 0603 R5 0Ω, 1%, 0603 R6 1M, 1%, 0603 D1 SS34 Packing Information SOT-23-6L Units: mm VER 1.2 4 ACE714B Step-up DC/DC Converter Backlight Driver Notes ACE does not assume any responsibility for use as critical components in life support devices or systems without the express written approval of the president and general counsel of ACE Electronics Co., LTD. As sued herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and shoes failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ACE Technology Co., LTD. http://www.ace-ele.com/ VER 1.2 5