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n0106hkim b8-9151 no.a0089-1/11 LC410591FN overview the LC410591FN is a power supply ic for white leds. it incorporates a charge pump-t ype dc/dc converter circuit and has four constant-current outputs. the input voltage ranges from 2.7v to 5.5v. the maximum value of the current flowing to the leds can be determ ined by the resistance value of the ex ternal resistors. the LC410591FN can supply a total current of 105ma for one to four white leds. a maximum current of 26ma can be supplied to one white led when driving four leds, and a maximum curr ent of 35ma can be supplied to one white led when driving three leds. the ic operates at a fixed frequency of 600khz without using an in ductor, resulting in very low emi noise. the led brightness is adjusted by a pwm pulse signal to the brgt pin. when a low level is applied for 22ms or longer to the brgt pin, the ic enters the shutdown mode. this ic comes in the vqfn 16 package (4mm 4mm). features ? built-in low-noise and high-efficiency cmos charge pump ? built-in constant-current generating circuit ? input voltage range of 2.7v to 5.5v ? driving of 1 to 4 white leds at a total current of 105ma ? automatic switching of charge pump voltage step-up ratio ( 1, 1.5) ? 1.5% (typ) led to led current matching ? soft start for preventing rush current ? charge pump frequency of 600khz ? brightness adjustment control with a pwm signal ? 1 a maximum shutdown current applications ? white led display backlights ? white led keypad backlights ? pdas, cell phones, fpds, and ot her equipment that operate with a single lithium-ion battery ordering number : ena0089 cmos ic power supply ic with built-in white led charge pump any and all sanyo semiconductor products described or contained herein do not have specifications that can handle applications that require extremely high levels of reliability, such as life-support systems, aircraft's control systems, or other applications whose failure can be reasonably expected to result in serious physical and/or material damage. consult with your sanyo semiconductor representative nearest you before usingany sanyo semiconductor products described or contained herein in such applications. sanyo semiconductor assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated val ues (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all sanyo semiconductor products described or contained herein.
LC410591FN no.a0089-2/11 specifications absolute maximum ratings at ta = 25 c parameter symbol conditions ratings unit maximum supply voltage v dd -0.3 to +7.2 v maximum supply voltage v ss -0.3 to +0.3 v storage temperature tstg -55 to +125 c allowable operating range at ta=-40 c to 85 c (unless otherwise specified, ta=25 c) supply voltage (v in )=3.6v, r set =3.2k ? , led forward voltage (v f )=3.2v, input bypass capacitor (c in )=2.2 f, output smoothing capacitor (c cp )=2.2 f ratings parameter symbol conditions min typ max unit supply voltage v in 2.7 5.5 v maximum output current ta=25 c 105 ma ta=25 c, 4 leds lit 26 ma maximum led current (per 1 led) ta=25 c, 3 leds lit 35 ma v in =4.1 to 5.5v ( 1 mode) 2 ma no-load supply current ( 100% i led ) v in =2.7 to 4.1v ( 1.5 mode) 5 ma charge pump frequency 600 khz charge pump mode-switching supply voltage when switching from 1 to 1.5 4.1 v charge pump mode-switching supply voltage hysteresis 0.5 v reference voltage output 1.2 v iset bias 1.2 v led current absolute accuracy 3 % led to led current matching 1.5 % shutdown time supply current v in =2.7 to 5.5v,ta=25 c 1 a input signal frequency (pwm) brgt input 100 50k hz ta=25 c,v in =4.5 to 5.5v 3 v brgt signal high threshold value ta=25 c,v in =2.7 to 4.5v 2.5 v brgt signal low threshold value ta=25 c,v in =2.7 to 5.5v 0.5 v brgt input current (h level) ta=25 c 1 a brgt input current (l level) ta=25 c -1 a (note 1) electrical characteristics at ta=-40 c indicate design guaranteed values.
LC410591FN no.a0089-3/11 package dimensions unit : mm (typ) 3316 application example ilc01756 2.2 f 2.2 f 1 f 1 f 1nf vcp v in c1a c1b c2a c2b brgt vref iset led_in1 led_in2 led_in3 led_in4 gnd sanyo : vqfn16(4.0x4.0) side view side view top view bottom view 4.0 4.0 3.75 3.75 0.9 max (0.85) 0.01 0.6 0.28 0.65 (1.025) (2.50) (2.50) exposed die-pad do not connect 1 1 4 5 8 912 13 16 4 5 8 9 12 1 3 1 6
LC410591FN no.a0089-4/11 pin assignment pin functions pin name pin no. pin description v in 2 power supply input pin. connects a capacitor of 2.2 f between the v in pin and gnd pin. c1a 4 flying capacitor (1)+ c1b 7 flying capacitor (1)- c2a 6 flying capacitor (2)+ c2b 3 flying capacitor (2)- brgt 15 led brightness adjustment signal input. led current is adjusted by pwm signal (max. 50khz). the led current changes linearly with respect to the pwm signal duty ratio and the brightness changes. when the low level continues for 22ms or longer, the LC410591FN enters the shutdown mode, and the led turns off. iset 13 external resistor pin. the maximum led current is determined by i led (ma)=48/r set (k ? ). vref 16 internal reference voltage output (standard 1.2v). connect a capacitor of 1nf between the vref pin and gnd pin. the vref pin must always be set to a high impedance state. gnd 8 power supply gnd. the switching current of the charge pump flows to this pin. led_in1 to 4 9-12 connect leds between the vcp pin and led_in1 to in4. if not connected, set these pins to open or connect to g nd. vcp 5 charge pump output. c onnect a capacitor of 2.2 f between the vcp pin and gnd pin. test 14 not used. always set to open. ilc01757 12 11 10 9 1234 5 6 7 8 16 15 14 13 led_in1 led_in2 led_in3 led_in4 nc** v in c2b c1a top vie w iset test* brgt vref gnd c1b c2a vcp
LC410591FN no.a0089-5/11 block diagram ilc01758 2.2 f 2.2 f 1 f 1 f 1nf vcp v in brgt vref r set iset current mirror soft start circuit charge pump boost mode selector oscillator clock generator brightness controller band gap reference led_in1 to 4
LC410591FN no.a0089-6/11 standard electrical characteristics unless otherwise specified, supply voltage (v in )=3.6v, r set =3.2k ? , led forward voltage (v f )=3.2v, ta=25 c, 4-light control input bypass capacitor (c in )=2.2 f, output smoothing capacitor (c cp )=2.2 f, flying capacitor (c1,c2)=1 f led current - supply voltage 20 15 10 5 0 3.0 3.5 4.0 4.5 5.0 ilc01759 led current - ma supply current - supply voltage supply current - ma supply voltage - v v f =3.2v v f =3.4v v f = 3 . 6 v v f = 3 . 6 v v f = 3 . 2 v v f = 3 . 2 v v f = 3 . 4 v v f = 3 . 4 v led current - supply voltage 20 15 10 5 0 3.0 3.5 4.0 4.5 5.0 ilc01760 led current - ma supply voltage - v led efficiency - supply voltage 100 80 60 40 20 0 3.0 3.5 4.0 4.5 5.0 ilc01761 led efficiency - % led efficiency - supply voltage led efficiency - % supply voltage - v 100 80 60 40 20 0 3.0 3.5 4.0 4.5 5.0 ilc01763 supply voltage - v supply current - supply voltage supply current - ma 100 80 60 40 20 0 3.0 3.5 4.0 4.5 5. 0 ilc01764 supply voltage - v 80 60 40 20 0 3.0 3.2 4.0 4.2 3.4 3.6 3.8 4.4 5.0 4.8 4.6 ilc01762 supply voltage - v 60c 25c 6 0 c 2 5 c 6 0 c 2 5 c
LC410591FN no.a0089-7/11 unless otherwise specified, supply voltage (v in )=3.6v, r set =3.2k ? , led forward voltage (v f )=3.2v, ta=25 c, 4-light control input bypass capacitor (c in )=2.2 f, output smoothing capacitor (c cp )=2.2 f, flying capacitor (c1,c2)=1 f charge pump efficiency - supply voltage 3.0 3.5 4.0 4.5 5.0 ilc01765 charge pump efficiency - % led current - supply voltage led current - ma supply voltage - v led current - duty ratio of brgt signal led current - brgts duty ratio 6 3 4 5 2 1 0 6 3 4 5 2 1 0 3.0 3.5 4.0 4.5 5.0 ilc01766 current of 4 leds - ma led current - ma duty ratio - % duty ratio - % 120 100 80 60 40 20 0 100 80 60 40 20 0 0 20 40 60 100 80 0 20 40 60 100 80 ilc01767 30 25 20 15 10 5 0 3.0 3.5 4.0 4.5 5.0 ilc01769 supply voltage - v output voltage - supply voltage output voltage- v supply current - supply voltage supply current - ma 3.0 3.5 4.0 4.5 5.0 ilc01770 supply voltage - v supply voltage - v 50 40 30 20 10 0 ilc01768 60c 25c 6 0 c 2 5 c 6 0 c 2 5 c 6 0 c 2 5 c r s e t = 2 k ? r s e t = 3 k ? r s e t = 2 k ? r s e t = 3 . 3 k ?
LC410591FN no.a0089-8/11 functional description circuit description the LC410591FN is a white led driver that uses a li-ion ba ttery as its power supply. the output voltage range of the li-ion battery is approximately 2.7v to 5.5v, and a typical white led forward voltage (v f ) is approximately 3.6v. therefore, when the supply voltage is 3.6v or less, the voltage must be stepped up internally. the LC410591FN incorporates a charge pump that steps up the supply voltage 1.5 times. this charge pump automatically switches to the optimum step-up mode. the 100% led current is determined by th e resistance values of the external re sistors. in other words, the internal reference voltage (v ref 1.2) is applied precisely to the external resistor s by the internal op amplifier, and the current flowing to the external resistors (i rset ) becomes i rset =v ref /r set . the led current (i led ) is regulated by a current mirror circuit so that 40 times the i rset current flows. for example, if v ref =1.2v and r set =2k ? , then i rset =0.6ma, and i led =i rset 40=24ma. in this case, for 4-light control, the total current flowing to the led is 24ma 4=96ma. however, this formula does not include the varia tion in the resistance values of the external resistors. if accurate led current is required, high-precision resistors (with a variation of 1% or less, for instance) may be required. the led brightness is adjusted by a serial signal to the brgt pin. shutdown mode the LC410591FN enters a shutdown mode when the low level is applied to the brgt pin for 22ms or longer. in the shutdown mode, the leds turn off, and the supply current is reduced to 1 a or less. soft start the LC410591FN performs a soft start to prevent rush curre nt, and then 100% current flows to the leds. a rush current is generated if the charge pump is activated when the flying capacitor is discharged. if the impedance of the capacitor is low, an excessive current will flow in from the battery. soft start is performed to reduce the stress on the battery and external components. during the soft start, the resistance of the switch connected to the flying capacitor and output smoothing capacitor is adjusted to prevent a rush current. brightness adjustment led brightness can be adjusted by controlling the current to the led with the pwm signal supplied to the brgt pin. the average current flowing to the leds depends on the pwm signal. [led average current=i led duty ratio] ?(fig. 2) the current flowing to the led (average value) changes in a nearly linear fashion with respect to the duty ratio of the pwm signal input to the brgt pin. ?(fig. 3) the upper limit of the pwm signal frequency is 50khz. fix the brgt signal to the low level for at least 22ms from power supply (v in ) rising.?(fig. 4) led current t t duty ratio=t/t frequency=1/t (fig. 2) i led 22ms or longer v in brgt (fig. 4) (fig. 3) iled - brgt duty iled - ma brgt duty - % 0 20 40 60 100 80 70 60 50 40 30 20 10 0 ilc01771 v in =3.6v,rset=3.3k ? brgt=1khz,4leds
LC410591FN no.a0089-9/11 selection of ext ernal capacitors low esr capacitors are recommended for the input bypass cap acitor, output smoothing cap acitor, and charge pump flying capacitor. also, ceramic capacitors are recommended for their low fluctuations due to temperature (such as x5r or x7r). adding leds for driving shown in figures 5 and 6 are sample circuit diagrams illustra ting the use of output voltage (vcp) of this ic when an led is added. note that the ic may not be able to conform to its specifications if the total led current exceeds 105ma. to limit the amount of current to the additional led, or to c ontrol the on/off switching of the current, it is necessary to connect a resistor or switch in series with the added led. (fig. 5) ilc01772 2.2 f 2.2 f 1 f 1 f 1nf vcp v in c1a c1b c2a c2b brgt vref iset led_in1 led_in2 led_in3 led_in4 gnd
LC410591FN no.a0089-10/11 the connection shown in the figure below is also possible. (fig.6) however, in the case of the above connect ion, led current differences due to the characteristic differences of the leds connected to the same led_in by the cathode (fig. 7) are not adjusted. (fig.7) ilc01773 2.2 f 2.2 f 1 f 1 f 1nf vcp v in c1a c1b c2a c2b brgt vref iset led_in1 led_in2 led_in3 led_in4 gnd ilc01774 vcp led_in1
LC410591FN no.a0089-11/11 ps this catalog provides information as of november, 2006. specifications and information herein are subject to change without notice. specifications of any and all sanyo semiconductor pr oducts described or contained herein stipulate the performance, characteristics, and functions of the described products in the independent state, and are not guarantees of the performance, characteristics, and functions of the described products as mounted in the customer's products or equipment. to verify s ymptoms and states that cannot be evaluated in an independent device, the customer should always evaluate and test devices mounted in the customer's products or equipment. sanyo semiconductor co., ltd. strives to supply high- quality high-reliability products. however, any and all semiconductor products fail with some probabi lity. it is possible that these probabilistic failures could give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire, or that could cause damage to other property . when designing equipment, adopt safety measures so that these kinds of accidents or events cannot occur. such measures include but are not limited to protective circuits and error prevention circuits for safe design, redundant design, and structural design. in the event that any or all sanyo semiconductor produc ts (including technical data,services) described or contained herein are controlled under any of applicable local export control laws and regulations, such products must not be exported without obtaining the export license from the authorities concerned in accordance with the above law. no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording , or any information storage or retrieval system, or otherwise, without the prior written permission of sanyo semiconductor co., ltd. any and all information described or contained herein are subject to change without notice due to product/technology improvement, etc. when designing equipment, refer to the "delivery specification" for the sanyo semiconductor product that you intend to use. information (including circuit diagrams and circui t parameters) herein is for example only; it is not guaranteed for volume production. sanyo semicondu ctor believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties.

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