AMG-LL9910B Universal High Voltage Single Channel LED Driver 1. Functional Description of the AMG-LL9910B The AMG-LL9910B is a universal high voltage LED driver IC. Both buck and boost topologies are possible. It has one current regulated channel. The AMG-LL9910B controls an external MOSFET at fixed switching frequencies up to 300 kHz. The frequency can be programmed by using a single resistor. The LED string is driven at a constant current rather than a constant voltage, thus providing constant light output and enhanced reliability. The output current to a LED string can be programmed to any value between 0 and 100% by applying an external control voltage at the linear dimming control input. The IC provides a low-frequency PWM dimming input that can accept an external control signal with a duty ratio between 0% and 100% and a frequency of up to a few kilohertz. 2. Features Supply voltage 8VDC … 450VDC >90 % efficiency 8 – 450V input voltage Peak current mode converter Linear and PWM dimming capability Buck and Boost topology Pin compatible with other HV LED drivers SOP8 Package with exposed pad for a lower thermal resistance 3. Application The AMG-LL9910B is suitable for: DC/DC or AC/DC LED driver applications LED backlighting General-purpose LED lighting General-purpose constant current source Battery chargers AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 1 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 3.1. Example Application Drawing Vin DC Vin Vdd LD AMG LL9910B PWMD Gate Rosz CS GND Figure 1: Buck LED Driver AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 2 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver Table of Contents 1.Functional Description of the AMG-LL9910B......................................................................... 1 2.Features................................................................................................................................. 1 3.Application............................................................................................................................. 1 3.1.Example Application Drawing................................................................................................... 2 4.Block Diagram....................................................................................................................... 4 5.Block Descriptions................................................................................................................. 4 6.Pinning................................................................................................................................... 5 7.Absolute Maximum Ratings................................................................................................... 6 8.Electrical Characteristics........................................................................................................ 6 8.1.Operational Range................................................................................................................... 6 8.2.DC Characteristics................................................................................................................... 7 8.3.AC Characteristics.................................................................................................................... 7 9.Application............................................................................................................................. 8 9.1.Example Application Circuit...................................................................................................... 8 9.2.Application Notes..................................................................................................................... 8 9.3.Off Line LED Driver................................................................................................................. 11 9.4.Off Line LED Driver with Digital I/F.........................................................................................11 9.5.Off Line LED Driver with Temp-Protection..............................................................................12 9.6.Battery Powered LED Driver..................................................................................................12 10.Ordering Information.......................................................................................................... 13 11.IC-Package........................................................................................................................ 13 12.IC-Marking......................................................................................................................... 13 13.Notes and Cautions........................................................................................................... 14 13.1.ESD Protection..................................................................................................................... 14 13.2.Storage conditions................................................................................................................ 14 14.Disclaimer.......................................................................................................................... 14 15.Contact Information............................................................................................................ 15 AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 3 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 4. Block Diagram Regulator Vin LD + CS POR + UVLO 1 & Blanking + R Gate Q S - 250mV Vdd Oscillator PWMD GND Rosc Figure 2: Block Diagram 5. Block Descriptions Linear Regulator Generates a stable supply for the logic. May also supply external circuitry. POR + UVLO Power on Reset and Under Voltage lockout. The IC is released from reset, after the Vdd rises above the UVLO voltage. Linear Dimming Comparator Manual setting of the VCS threshold. Current Sense Comparator Current limiting comparator. Blanking Timer Inserts a time delay from CS trip to Gate low, in order to enable100% duty cycle. AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 4 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver RS Flip Flop Enables and disables the gate driver. Set by the oscillator, reset by current limit. Gate Driver Drives external MOSFET. Gated by external PWM or enable signal. Oscillator Determines PWM frequency. 6. Pinning Vin Supply input 2 CS Current Sense 3 GND Ground 4 Gate Driver output for external MOSFET 5 PWMD PMW dimming input 6 Vdd Linear regulator output 7 LD Linear Dimming 8 Rosc Resistor to GND setting Oscillator Frequency EP - Thermal conductive pad on the bottom. Connect this pad to Ground, and provide sufficient thermal coupling to remove heat from the package. D M WP 1 dd V Description DL Symbol cs o R PIN# αLL9910 YYWW XXXX et a G AMG-LL9910B DN G SC ni V 1 Revision: B 09/13/12 © All rights reserved Page 5 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 7. Absolute Maximum Ratings The Absolute Maximum Ratings may not be exceeded under any circumstances. # Symbol Parameter Min Max Unit 1 Vin Supply input voltage -0.5 470 V 2 Vlogic Voltage on CS, LD, PWMD, Gate -0.3 Vdd + 0.3 V 3 Tj Junction temperature 150 °C 4 TS Storage temperature -65 150 °C 5 Vddmax Max. voltage at Vdd -0.3 12 V 6 Rthja Thermal resistance junction ambient 42 K/W 7 Ptot@25°C Total power dissipation 2.5 W Unit Note: All voltages are with respect to GND 8. Electrical Characteristics 8.1. Operational Range (Ta=25°C unless noted otherwise) # Symbol 1 Vin 1) 2 3 Note: Parameter Min Max Supply input voltage 10 450 Ta Operating ambient temperature -40 125 PWM Duty Cycle 1) 100 V 1) 2) °C % Also limited by maximum power dissipation, whichever is lower. 2) Rthja = (Tj –Ta) / Ptot AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 6 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 8.2. DC Characteristics (Ta=25°C unless noted otherwise) # Symbol Parameter Min Typ Max Unit 1 Vdd Regulator output voltage 7.25 7.5 7.75 V 2 Iext 3) 0.7 mA 3 UVLO Undervoltage lockout (Vdd rising) 6.95 V 4 ΔUVLO Undervoltage lockout hysteresis (Vdd falling) 5 Vin low Input voltage logic low (PWMD) 6 Vin high Input voltage logic high (PWMD) 2 7 RPWMD Pull down on PWMD pin 50 100 150 kΩ 8 Vcs Current sense threshold 225 250 275 mV 10 Vgate low Gate driver low output voltage (@10mA) 0 0.3 V 11 Vgate high Gate driver high output voltage (@-10mA) Vdd-0.3 Vdd V 12 Idd Current consumption (shutdown), VPWM =0V 0.5 1 mA Note: 3) Current for ext. circuitry (10V < Vin < 100V) 6.45 6.7 500 mV 0.8 V V Also limited by maximum power dissipation, whichever is lower. 8.3. AC Characteristics (Ta=25°C unless noted otherwise) # Symbol Parameter Min Typ Max Unit 1 fOSC Oscillator frequency @ ROSC=1000kOhm 20 25 30 kHz Oscillator frequency @ ROSC=226kOhm 80 100 120 kHz 2 tblank Minimal gate on time (Current sense blanking time) 150 215 280 ns 3 tdelay Time from CS trip to Gate low 80 150 ns 4 trise Gate driver output rise time (Cgate = 500pF) 30 50 ns 5 tfall Gate driver output fall time (Cgate = 500pF) 30 50 ns AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 7 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 9. Application 9.1. Example Application Circuit Vin DC Vin Vdd LD AMG LL9910B PWMD Gate Rosc CS GND Figure 3: Buck LED Driver 9.2. Application Notes a) Peak Current Regulation The oscillator resistor sets the PWM frequency. After each oscillator period, the gate driver is pulled high and the duty cycle begins. When the current over sense resistor RCS reaches the current limit, the current sense comparator will trip and after blanking time the gate driver output is pulled low and the duty cycle ends. Smaller inductors and lower PWM frequencies will provide for higher current ripple. In the case that the highest light intensity is desired, the ripple should be maximized and the LED driven to it's specified peak current limit. In the case that the highest efficacy and longest LED lifetime is desired, the LED needs to be driven to the optimum current value only. In this situation, the ripple should be kept as low as possible. Bigger inductor values and higher PWM frequencies will help achieve this result. AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 8 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver b) LED Current The maximum LED current is programmed with an external resistor RCS. If peak current for highest light intensity is desired, the resistor value should be calculated as follows: RCS = 250mV/ILED peak If an average current for highest efficacy and longest lifetime is desired, the resistor value should be calculated as follows: RCS = 250mV/[ILED avg + (0.5*ΔIL)] ΔIL = Iripple c) Inductor Value The inductor value depends on the input voltage, output voltage, PWM frequency and the desired current ripple. First , we calculate the ratio between input and output voltage and the voltage over the inductor. The input voltage is the average supply voltage for the IC while the output voltage is the number of LEDs on the string times the LED forward voltage. Vout = n * VF VL = Vin - Vout Please note: that the forward LED voltage is a function of the LED current. The LED data sheet should provide the corresponding forward voltage for a given LED current. D = Vout/Vin For a buck design, D must be lower than 1. Then, the ripple of the LED currents needs to be determined, which will then provide the actual inductor value. For the maximum peak current (highest intensity), a current ripple higher than 50% (0.5) is desirable. ΔIL = ripple * ILED peak Inductor values should be rounded down in this case. For a stable average current (highest efficacy), a current ripple lower than 20% (0.2) is desirable. ΔIL = ripple * ILED avg Inductor values should be rounded up for this case. L= (D/fosc) * (VL/ΔIL) AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 9 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver d) Linear Dimming If the second comparator is provided with a threshold voltage lower than the internal threshold voltage of the first comparator, the current over the LED can be manually adjusted. This can be achieved with any analog voltage between 0 and the internal reference voltage (e.g. with a potentiometer). e) Digital Dimming With an external PWM signal at the PWMD pin, the gate driver can be gated. This means, the LED will light up during the duty cycle of the external PWM signal and vice versa, the LED will be off during the off-time of the external PWM signal. The external PWM frequency needs to be much smaller than the frequency of the AMG-LL9910B. The external PWM frequency should be at least 10x smaller, otherwise fluctuation effects may occur. The PWMD pin may also be used to enable or disable the device. The IC is enabled, when PWMD is pulled to Vcc. It is disabled, when PWMD is pulled to GND: f) PWM Frequency FPWM [kHz] = 25000/(Rosc [kΩ]+22) g) PFC The AMG-LL9910B does not have a PFC integrated stage. As such, a PFC is usually necessary for off line LED drivers. This can be either a passive PFC or even an active one, when the power increases relatively high. AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 10 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 9.3. Off Line LED Driver 10mH 22µF / 400V 325V DC UF4007 350mA Vin Vdd 82k Enable AMG LL9910B LD PWMD e.g.. IRFxxx Gate 3k 4,7 µF Rosc CS GND 0,7R 220k Figure4: Buck topology, linear dimming, enable switch 9.4. Off Line LED Driver with Digital I/F 10mH 325V DC UF4007 22µF / 400V 350mA Vin Vdd Enable LD PWM in AMG LL9910B PWMD 4,7 µF Gate e.g. IRFxxx 10k Rosc CS GND 0,7R 220k Figure 5: Buck topology, digital dimming, enable signal AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 11 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 9.5. Off Line LED Driver with Temp-Protection 10mH 22µF / 400V 325V DC UF4007 350mA Vin Vdd 33k LD AMG LL9910B PWMD Thermally connect to LEDs e.g. IRFxxx Gate 1k NTC Rosc ϑ CS GND 4,7 µF 0,7R 220k Figure 6: Buck topology, with Temp-Protection 9.6. Battery Powered LED Driver 47µF / 16V 12V DC 1mH UF4004 Vin Vdd 10µF / 60V AMG LL9910B LD PWMD Gate e.g. IRFxxx 4,7 µF Rosc CS GND 350mA 0,3R 100k Figure 7: Boost topology AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 12 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 10. Ordering Information AMG-LL9910B-ISO08U SOP8 in tubes AMG-LL9910B-ISO08R SOP8 in tape and reel 11. IC-Package SOP8 with exposed pad 4.90±0.10 6.00±0.20 Exposed Pad 3.90±0.10 Exposed Pad Not connected with any of the leads 1.27 0.42±0.09 0.00 ... 0.10 1.50±0.10 0.22±0.03 All dimensions in mm 12. IC-Marking αLL9910 4 digit date code 4 … 6 digit lot code AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 13 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 13. Notes and Cautions 13.1. ESD Protection The Requirements for Handling Electrostatic Discharge Sensitive Devices are described in the JEDEC standard JESD625-A. Please note the following recommendations: When handling the device, operators must be grounded by wearing a grounded wrist strap with at least 1MΩ resistance with direct skin contact. Operators must at all times, wear ESD protective shoes or the area should be surrounded by ESD protected floor mats. The opening of an EDS protective package or device must only occur on a properly equipped ESD workbench. The tape with which the package is held together must be cut with a sharp cutting tool, never pulled or ripped off. Any unnecessary contact with the device or any unprotected conductive points should be avoided. Only work with qualified and grounded tools, measuring equipment, casings and workbenches. When outside of properly protected ESD-areas, the device or any electronic assembly must be protected and always be transported in EGB/ESD shielded packaging. 13.2. Storage conditions The AMG-LL9910B corresponds to moisture sensitivity classification ML2, according to JEDEC standard J-STD-020, and should be handled and stored according to J-STD-033. 14. Disclaimer Information given in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed for the consequences of its use nor for any infringement of patents or other rights of third parties that may result from its use. The values stated in Absolute Maximum Ratings may under no circumstances be exceeded. No warranty is given for use in life support systems or medical equipment without the specific written consent of alpha microelectronics gmbh. For questions regarding the application please contact the publisher. The declared data are only a description of the product. They are not guaranteed properties as defined by law. Samples are provided without obligation and cannot give rise to any liability. Reprinting of this data sheet – or any part of it – is not allowed without the license of the publisher. Data sheets are subject to change without any notice. AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 14 of 15 AMG-LL9910B Universal High Voltage Single Channel LED Driver 15. Contact Information This data sheet is published by alpha microelectronics gmbh. To order samples or inquire information please contact: alpha microelectronics gmbh Im Technologiepark 1 15236 Frankfurt (Oder) Germany [email protected] www.alpha-microelectronics.de +49-335-557-1750 (telephone) +49-335-557-1759 (fax) © All rights reserved. AMG-LL9910B Revision: B 09/13/12 © All rights reserved Page 15 of 15