View AL8811M8-13_6583842.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

al8811 document number: ds36090 rev. 2 - 2 1 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 boost/buck/inverting dc-dc converter description the al8811 is a monolithic control circuit containing the primary functions required for dc-to-dc conv erters. these devic es consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. this se ries is specifically designed for incorporating in boost, buck and volt age-inverting applications with a minimum number of external components. features ? operation from 3.0v to 20v input ? low standby current ? current limiting ? output switch current to 1.6a ? output voltage adjustable ? frequency operation to 100 khz ? precision 2% reference ? totally lead-free & fully rohs compliant (notes 1 & 2) ? halogen and antimony free. ?green? device (note 3) ? pin assignments msop-8 applications ? low voltage led lighting such as mr-16 ? general purpose dc-dc converter notes: 1. no purposely added lead. fully eu directiv e 2002/95/ec (rohs) & 2011/6 5/eu (rohs 2) compliant. 2. see http://www.diodes.com/quality/lead_free.html for more in formation about diodes incorporated?s definitions of halogen- a nd antimony-free, "green" and lead-free. 3. halogen- and antimony-free "green? products are defin ed as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total br + cl) and <1000ppm antimony compounds. typical application diagram electronic transformer compatible mr16 lamp simplified schematic ?
al8811 document number: ds36090 rev. 2 - 2 2 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 pin descriptions pin name pin number descriptions current switch+ 1 internal switch tr ansistor collector: connect to inductor for boost converter. connect to v cc for buck or inverting converter current switch- 2 internal switch transistor emitter: connect to gnd for boost converter connect to inductor for buck or inverting converter ct 3 timing capacitor to control the switching frequency gnd 4 feedback 5 feedback pin for inverting input of internal comparator vcc 6 supply voltage pin current sense 7 peak current sense input by monitoring the voltage drop across an external current sense resistor to limit the peak current through the switch current drive 8 current drive collector: normally connected to v cc directly or via a resistor. functional diagram
al8811 document number: ds36090 rev. 2 - 2 3 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 absolute maximum ratings (@t a = +25c, unless otherwise specified.) symbol parameter rating unit v cc power supply voltage 20 v v ir comparator input voltage range -0.3 to +36 v v c (switch) ?current switch +? collector voltage 36 v v e (switch) ?current switch ?? emitter voltage (v pin 1 = 36v) 36 v v ce (switch) ?current switch? collector to emitter voltage 36 v v c (driver) ?current drive? collector voltage 36 v i c (driver) ?current drive? collector current 100 ma i sw ?current switch? current 1.6 a p d power dissipation (note 4) 600 mw ? ja thermal resistance 130 ? c/w t mj maximum junction temperature +150 ? c t stg storage temperature range -65 to +150 ? c esd hbm human body model esd protection 1 kv esd mm machine model esd protection 150 v caution: stresses greater than the 'absol ute maximum ratings' specified above, may cause permanent damage to the device. these are stress ratings only; functional operation of the devic e at these or any other conditions exceeding thos e indicated in this s pecification is not impl ied. device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. semiconductor devices are esd sensitive and may be damaged by exposure to esd events. suitable esd precautions should be take n when handling and transporting these devices. recommended operating conditions symbol parameter min max unit v cc supply voltage 3 20 v t op operating junction temperature range -40 +105 ? c electrical characteristics (@ v cc = 5v, t a = +25c, unless otherwise specified.) symbol parameter min typ max unit oscillator f osc frequency (v pin 5 = 0v, c t = 1.0nf, t a = +25c) 24 33 42 khz i chg charge current (v cc = 5.0v to 20v, t a = +25c) 24 30 42 a i dischg discharge current (v cc = 5.0v to 20v, t a = +25c) 140 200 260 a i dischg / i chg discharge to charge current ratio (pin 7 to v cc , t a = +25c) 5.2 6.5 7.5 ? v ipk (sense) current limit sense voltage (i chg = i dischg , t a = +25c) 300 400 450 mv output switch (note 4) v ce(sat) saturation voltage, darlington connection (i sw = 1.0a, pins 1, 8 connected) ? 1.0 1.3 v v ce(sat) saturation voltage, darlington connection (i sw = 1.0a, id = 50ma, forced ? ? 20) ? 0.45 0.7 v h fe dc current gain (i sw = 1.0a, v ce = 5.0v, t a = +25c) 50 75 ? ? i c(off) collector off-state current (v ce = 20v) ? 0.01 100 a comparator v th threshold voltage t a = +25c 1.225 1.25 1.275 v reg (line) threshold voltage line regulation (v cc = 3.0v to 20v) ? 1.4 6.0 mv total device i cc supply current (v cc = 5.0v to 20v, c t =1.0nf, pin 7 = v cc , v pin 5 > v th pin 2 = gnd, remaining pins open) ? ? 3.5 ma
al8811 document number: ds36090 rev. 2 - 2 4 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 typical performance characteristics figure 1. vce(sat) versus le 0.6 0.8 1 1.2 1.4 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 ie, emitter current (a) vce(sat), saturation voltage (v) 1.24 1.245 1.25 1.255 1.26 0 102030405060708090100 temperature ( o c) reference voltage (v) figure 2. reference voltage versus temp. figure 4. standby supply current versus supply voltage 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 5 10 15 20 25 30 35 40 vcc, supply voltage (v) icc, supply current (ma) 1.4 1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 100 300 500 700 900 1100 1300 1500 i e (ma) v ce ( sat), (v) figure 5. emitter follower configuration output saturation voltage vs. emitter current 0.1 1 10 100 1000 0.01 0.1 1 10 c t , oscillator timing capacitor ( nf) t on-off , output switch on-off time(us) figure 6.output switch on-off time versus oscillator timing capacitor v cc = 5.0v pin 7 = v cc pin 5 = gnd t a = 25 o c t on t off vcc=2~10v pin1,7,8=vcc pin3,5=gnd t a =25 o c pin2=5 figure 3. current limit sense voltage versus temperature 320 340 360 380 400 420 440 0 1020 3040 50 6070 8090100 temperature ( o c) current sense voltage (mv) ? 10w
al8811 document number: ds36090 rev. 2 - 2 5 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 application circuit (1) boost converter test conditions results line regulation v in = 9v to 12v, i o = 200ma 20mv = 0.035% load regulation v in = 12v, i o = 50ma to 200ma 15mv = 0.035% output ripple v in = 12v, i o = 200ma 500mv pp efficiency v in = 12v, i o = 200ma 80%
al8811 document number: ds36090 rev. 2 - 2 6 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 application circuit (cont.) (2) electronic transformer compatible triac dimmable mr16/gu5.3 lamp for 120vac circuit description this design consists of three sections: 1) the input pfc circuit converts the 12v ac input voltage to a dc voltage around 30v (al8811). 2) the output buck led driver drives the three leds in series at a fixed current (al8807a). 3) finally, the phase-detect circuit generates a voltage proportional to the phase of the incoming ac voltage (when triac dimm ing is used). pfc circuit the al8811 boost converter is a simple ?const ant on time controller?. by keeping the same on time throughout the ac cycle, the circuit will draw a current that will closely match the voltage and result in a constant input current. this eliminates the classic peak cu rrent problem with a bridge rectifier and a large input filter capacitor. the pfc circuit includes the input bridge rectifier, emi filter (if needed) and the al8811 boost converter. the ac input volta ge is rectified by the bridge circuit and filtered by c1, r1, c4, and c5. this first filter removes the high frequency that is generated by the elect ronic transformer in the range of 20-30 khz. an additional diode rectifier circuit (d5, c2) is used to generate a voltage that is used to power the cir cuit that will turn on/off the external mosfet of the boost converter. this circuit is very important as the gate drive of the mosfet has to be greater t han 3-4 volts throughout the ac cycle. the external mosfet is used to reduce the heat dissipation in the al8811. the al8811 has a current limit resistor r3 which sets the ma ximum current allowed through the inductor l1. the output voltage is set by the divider r6, r5 to an output of around 35 volts. the output voltage is filtered by the two capacitors c8 and c9. these two cap acitors store energy that will be used when the input voltage is low during the ac cycle.
al8811 document number: ds36090 rev. 2 - 2 7 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 application circuit (cont.) buck led driver the al8807a is a step-down dc-dc converter de signed to drive leds with a constant curr ent. the current through the led is cont rolled by r11. in the present evaluation board, the current is set to around 660ma based on a resistor value of 0.15 ? . the current is set using the ?ctrl? input pin which in this new version of the ic can vary from 0 to 2. 5v, controlling the current from 0ma to the maximum current at 2.5 v. this control input pin is used to lower the led current as the triac dims the led. in this way, the energy stored in the two output capacitors of the pfc circuit will be able to provide current throughout the ac cycle. triac phase detection circuit the phase of the triac is detected by usi ng an additional rectifier circuit that gener ates a voltage in proportional to the pha se of the triac driver. this is done by rectifying the input ac voltage and averaging the en ergy using a resistor to c harge a capacitor. two additiona l resistors in series, r12 and r8, slowly discharge this circuit so it will follow the input phase change. the two resistors, r12 and r8, are used to scale the voltage so the range is from 0 to 2.6v to the buck led driver control pin. a simple transistor emitter followe r circuit is used to drive a 1k ? resistor in the emitter circuit. this low resistance is needed to drive the input control pin of the al8807a led driver becaus e the pin outputs a small current of 50ua, which limits the lowest control voltage to around 50 mv. setting the led output current (al8807a): the led output current is set using resister r11 and the formula: i led = v th / r11 where v th is equal to 0.1v for a current of 660ma, r11 is about 0.15 ? . setting the pfc variables (al8811) the choice for the size of the boost conver ter inductor selected in this design is bas ed on a compromise which it is able to su pport a peak current to around 1.5a since the average input voltage will be around 12-14v. the boost converter (al8811) includes a current limit resistor r3 which will limit the current through the inductor and thus th e power delivered to the output load. the formula for the resistor is: i pk(switch) = 0.33v / r3 for a current limit of 1a, r3 is 0.33 ? . in this evaluation design, this value wa s selected based on having three leds in series drawing about 660ma. it was found that two 68f capacitors mounted in parallel would just fit into the cavity of the mr16 bulb. the important design goal is to have the pfc c ircuit, which is used to always draw current from the electronic transformer.
al8811 document number: ds36090 rev. 2 - 2 8 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 application circuit (cont.) (3) buck converter test conditions results line regulation v in = 12v to 20v, i o = 500ma 20mv = 0.2% load regulation v in = 20v, i o = 50ma to 500ma 5mv = 0.05% output ripple v in = 20v, i o = 500ma 160mv pp efficiency v in = 20v, i o = 500ma 82% 1.25v ref reg i pk c t r s q q2 q1 comp. + _ 8 7 6 5 1 2 3 4 v c c osc + 470 uf v in 20 r sc 0.11 r1 25k 36k r2 + c o 5.0v/500ma v out + 100 v out optional filter c t 470 pf l 100uh b240 470uf 1.0uh
al8811 document number: ds36090 rev. 2 - 2 9 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 application circuit (cont.) (4) voltage inverting converter test conditions results line regulation v in = 4.5v to 6.0v, i o = 100ma 20mv = 0.08% load regulation v in = 5.0v, i o = 20ma to 100ma 30mv = 0.12% output ripple v in = 5.0v, i o = 100ma 500mv pp efficiency v in = 5.0v, i o = 100ma 60%
al8811 document number: ds36090 rev. 2 - 2 10 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 ordering information part number package code packaging tube 13? tape and reel quantity part number suffix quantity part number suffix AL8811M8-13 m8 msop-8 na na 2500/tape & reel -13 marking information (1) msop-8 al8811 ( top view ) y w x part number logo y : year : 0~9 internal code 87 65 1 234 a~z : 27~52 week; z represents w : week : a~z : 1~26 week; 52 and 53 week package outline dimensions (all dimensions in mm.) please see ap02002 at http://www.diodes.com /datasheets/ap02002.pdf for latest version. msop-8 dim min max typ a - 1.10 - a1 0.05 0.15 0.10 a2 0.75 0.95 0.86 a3 0.29 0.49 0.39 b 0.22 0.38 0.30 c 0.08 0.23 0.15 d 2.90 3.10 3.00 e 4.70 5.10 4.90 e1 2.90 3.10 3.00 e3 2.85 3.05 2.95 e - - 0.65 l 0.40 0.80 0.60 a 0 8 4 x - - 0.750 y - - 0.750 all dimensions in mm a a1 a2 e seating plane gauge plane l see detail c detail c c a e1 e3 a3 1 e y x d b 0.25 4 x 1 0 4 x 1 0
al8811 document number: ds36090 rev. 2 - 2 11 of 11 www.diodes.com june 2013 ? diodes incorporated a l8811 suggested pad layout please see ap02001 at http://www.diodes.com/dat asheets/ap02001.pdf for the latest version. important notice diodes incorporated makes no warranty of any kind, express or implied, with regards to this document, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose (and their equivalents under the laws of any jurisdiction). diodes incorporated and its subsidiaries rese rve the right to make modifications, enhanc ements, improvements, corrections or ot her changes without further notice to this document and any product descri bed herein. diodes incorporated does not assume any liability ari sing out of the application or use of this document or an y product described herein; neither does di odes incorporated convey any license under its patent or trademark rights, nor the rights of others. any customer or us er of this document or products described herein in such applica tions shall assume all risks of such use and will agree to hold diodes incorporated and all the companies whose products are represented on diodes incorporated website, harmless against all damages. diodes incorporated does not warrant or accept any liability w hatsoever in respect of any products purchased through unauthoriz ed sales channel. should customers purchase or use diodes inco rporated products for any unintended or una uthorized application, customers shall i ndemnify and hold diodes incorporated and its representativ es harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death a ssociated with such unintended or unauthorized application. products described herein may be covered by one or more united states, international or foreign patents pending. product names and markings noted herein may also be covered by one or more united states, international or foreign trademarks. this document is written in english but may be translated into multiple languages for reference. only the english version of t his document is the final and determinative format released by diodes incorporated. life support diodes incorporated products are specifically not authorized for use as critical component s in life support devices or systems without the express written approval of the chief executive offi cer of diodes incorporated. as used herein: a. life support devices or syst ems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when proper ly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in significant injury to the user. b. a critical component is any component in a life support devic e or system whose failure to perform can be reasonably expect ed to cause the failure of the life support device or to affect its safety or effectiveness. customers represent that they have all necessary expertise in the safety and regulatory ramifi cations of their life support dev ices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-rel ated requirements concerning the ir products and any use of diodes incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or s ystems-related information or support that may be provided by diodes incorporated. further, customers must fully indemnify diodes incorporate d and its representatives against any damages arisi ng out of the use of diodes incorporated pr oducts in such safety-critical, life suppor t devices or systems. copyright ? 2013, diodes incorporated www.diodes.com dimensions value (in mm) c 0.650 x 0.450 y 1.350 y1 5.300 x c y y1

▲Up To Search▲

Price & Availability of AL8811M8-13

	To Download AL8811M8-13 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .