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-1- NJU6052 ver.2004-02-26 white led driver with automatic dimming control general description the NJU6052 is a white led driver with an automatic dimming control. it contains an output driver, a pwm controller, a luminance sensor control (power supply for sensor & a/d converter), a step-up dc/dc converter, a serial interface, etc. the output driver ensures a 60ma maximum capability which allows the connection of 12 white leds (4 series x 3 parallels). depending on the ambient light sensed with an external luminance sensor, the pwm controller controls pwm duty in 8 steps preselected out of 64 steps. in addition, the frequency of the dc/dc converter is high so that it permits the use of small, low-profile inductors and capacitors to minimize the footprint in space-conscious applications. all of these benefits make the NJU6052 suitable for the battery-powered portable applications such as a cellular phone, a camcorder, pda, etc. features drives up to 12 white leds (4 series x 3 parallels) v sw = 18.0v(max.), i out = 60ma built-in pwm dimming control (selectable 8 out of 64 steps) built-in luminance sensor control (power supply for sensor & a/d converter) (no mpu-access required after initial setting) built-in temperature compensation circuit to suppress the characteristic degradation of leds uses small inductor and capacitors 1.8v to 3.6v operating voltage for logic circuits (v ddl ) 3.0v to 5.5v operating voltage for step-up circuits (v dd ) cmos technology package : qfn28 / ssop20 preliminary package outline NJU6052kn1 NJU6052 v
- 2 - NJU6052 ver.2004-02-26 qfn20 pin connections (top view) ssop20 pin connections (top view) sw sw sw test nc vdd vddl req dat a sc k vout fb vss ref c x vso sens rstb vss vss test nc vdd vddl req nc nc data sck vso sens rstb nc nc vss vss vss ref c x nc nc sw sw sw vout fb nc nc
-3- NJU6052 ver.2004-02-26 pin description no. qfn ssop symbol type descriptions 4 6 v dd power v dd power supply - power supply for step-up voltage 5 7 v ddl power v ddl power supply - power supply for logic voltage. - relation:1.8v v ddl v dd should be maintained. 25 26 27 1 2 3 sw input switch - all these terminals should be connected together. 10 10 sck input shift clock - serial data is latched on the rising edge of sck. 9 9 data input / output serial data 2 4 test output test - this terminal must be open. 6 8 req input data request ?l? : writing command data ?h? : reading sensor data 12 12 sens input luminance sensor connection 11 11 rstb input reset - active ?l?. 24 20 v out input input - this terminal is connected to led anode. 23 19 fb input feedback 18 19 20 16 17 18 v ss power ground - all these terminals should be connected together. 16 14 cx/tclk input oscillator capacitor connection / external clock input 13 13 v so output v so power supply - power supply for luminance sensor - 2.4v typical 17 15 ref input reference voltage - this terminal must be open. 1 3 7 8 14 15 21 22 28 5 nc - non connection - these terminals must be open.
- 4 - NJU6052 ver.2004-02-26 block diagram sens pwm controller serial interface reset v dd sw v out fb v ss v ddl req sck data rstb osc v ref l1 d1 c1 c2 a1 a2 ref a/d converter register r led regulator v so logic cx/tclk test
-5- NJU6052 ver.2004-02-26 functional descriptons (1) led current control the NJU6052 incorporates the led current control circuit to regulate the led current (i led ), which is programmed by the feedback resistor (r led ) connected between the fb and v ss terminals. the reference voltage v ref is internally regulated to 0.6v typical and connected to the positive input of the built-in comparator a1. formula (1) is used to choose the value of the r led , as shown below. v ref =0.6v (typ.) referring to the block diagram is recommended for understanding the operation of the led current control. the i led is the constant current programmed by the r led . when the feedback voltage on the fb terminal reaches above the reference voltage v ref on the ref terminal (i.e., i led is above the level programmed by r led ), the output capacitor c2 delivers the i led . once the feedback voltage drops below the reference voltage (i.e., i led drops below the level programmed by r led ), the comparator a1 detects it and turns on the internal mos switch, then the current of the inductor l1 begins increasing. when this switch current reaches 720ma and the comparator a2 detects it, or when the predetermined switch-on-period expires, the mos switch is turned off. the l1 then delivers current to the output through the diode d1 as the inductor current drops. after that, the mos switch is turned on again and the switch current increases up to 720ma. this switching cycle continues until the i led reaches the level programmed by the r led , then the i led is maintained constant. when the feedback voltage is less than 1/2*v ref , the current limit of the mos switch is reduced to 500ma typical. this action reduces the average inductor-current, minimizes the power dissipation and protects the ic against high current at start-up. the total forward-voltage of the leds must be greater than the power supply voltage v dd , otherwise the leds remain lighting up, being out of control. (2) oscillator the built-in oscillator incorporates a reference power supply, so its frequency is independent from the v dd . the frequency is varied by the external capacitor cx, as shown in figure 7. (3) luminance sensor control the luminance sensor control circuits consist of the power supply for sensor and the a/d converter. the a/d converter senses the voltage on the sens terminal and selects 1 out of 8 registers (pwm register 0?7). and the data in the selected register is reflected to the pwm duty (pwm dimming control). the contents of the registers can be programmed through the serial interface, in other words, the dimming control is user-settable. the voltage sense and the register selection are updated at regular intervals, and the interval period is set by the ?divide? bits. the selected register is held by setting ?1? at the ?hold? bit of the command data. led ref led i v r = --- formula (1)
- 6 - NJU6052 ver.2004-02-26 (4) pwm dimming control by setting the duty data at ?pwm register? bits, 8 out of 64 registers are assigned to the pwm register 0-7. the pwm duty is changed depending on the register selected by the sens voltage. the relation between the pwm register and its duty is shown below. table 1 pwm duty vs. pwm register register duty register duty register duty register duty 0,0,0,0,0,0 off 0,1,0,0,0,0 26.56% 1,0,0,0,0,0 51.56% 1,1,0,0,0,0 76.56% 0,0,0,0,0,1 3.13% 0,1,0,0,0,1 28.13% 1,0,0,0,0,1 53.13% 1,1,0,0,0,1 78.13% 0,0,0,0,1,0 4.69% 0,1,0,0,1,0 29.69% 1,0,0,0,1,0 54.69% 1,1,0,0,1,0 79.69% 0,0,0,0,1,1 6.25% 0,1,0,0,1,1 31.25% 1,0,0,0,1,1 56.25% 1,1,0,0,1,1 81.25% 0,0,0,1,0,0 7.81% 0,1,0,1,0,0 32.81% 1,0,0,1,0,0 57.81% 1,1,0,1,0,0 82.81% 0,0,0,1,0,1 9.38% 0,1,0,1,0,1 34.38% 1,0,0,1,0,1 59.38% 1,1,0,1,0,1 84.38% 0,0,0,1,1,0 10.94% 0,1,0,1,1,0 35.94% 1,0,0,1,1,0 60.94% 1,1,0,1,1,0 85.94% 0,0,0,1,1,1 12.50% 0,1,0,1,1,1 37.50% 1,0,0,1,1,1 62.50% 1,1,0,1,1,1 87.50% 0,0,1,0,0,0 14.06% 0,1,1,0,0,0 39.06% 1,0,1,0,0,0 64.06% 1,1,1,0,0,0 89.06% 0,0,1,0,0,1 15.63% 0,1,1,0,0,1 40.63% 1,0,1,0,0,1 65.63% 1,1,1,0,0,1 90.63% 0,0,1,0,1,0 17.19% 0,1,1,0,1,0 42.19% 1,0,1,0,1,0 67.19% 1,1,1,0,1,0 92.19% 0,0,1,0,1,1 18.75% 0,1,1,0,1,1 43.75% 1,0,1,0,1,1 68.75% 1,1,1,0,1,1 93.75% 0,0,1,1,0,0 20.31% 0,1,1,1,0,0 45.31% 1,0,1,1,0,0 70.31% 1,1,1,1,0,0 95.31% 0,0,1,1,0,1 21.88% 0,1,1,1,0,1 46.88% 1,0,1,1,0,1 71.88% 1,1,1,1,0,1 96.88% 0,0,1,1,1,0 23.44% 0,1,1,1,1,0 48.44% 1,0,1,1,1,0 73.44% 1,1,1,1,1,0 98.44% 0,0,1,1,1,1 25.00% 0,1,1,1,1,1 50.00% 1,0,1,1,1,1 75.00% 1,1,1,1,1,1 100.00% the relation between the pwm register and sens voltage is reversed by the ?rev? bit, as follows. table 2 rev vs. pwm register rev pwm register pwm register0 pwm register1 pwm register2 pwm register3 pwm register4 pwm register5 pwm register6 0 pwm register7 pwm register7 pwm register6 pwm register5 pwm register4 pwm register3 pwm register2 pwm register1 1 pwm register0 note 1) for the information on the relation between pwm duty and led current (i led ), refer to ?(9-1) pwm duty and led current?. note 2) for the information on the relation between sens voltage and pwm register, refer to ?dc electrical characteristics?.
-7- NJU6052 ver.2004-02-26 (5) serial interface (5-1) serial data write the serial data is latched into the shift register on the rising edge of the serial clock (sck), and determined on the rising edge of the data request (req). the serial data format should be the msb first. for command data transmission, the command data 1 (cmd1) and the command data 2 (cmd2) should be continuous. the cmd1 is first, then the cmd2. if only 1-byte data is transferred, this data is recognized as the cmd1. do not transmit 3 bytes or more, because 3 rd data is used only for maker test and the 4 th and later are ignored. if it's absolute necessary to send the 3 bytes or more in the user's application, the only data (0,0,0,0,0,0,0,0) as the 3 rd data can be accepted. for duty data transmission, 8 bytes for pwm register 0-7 should be continuous. the order is : pwm register 0, 1, 2, 3, 4, 5, 6 and 7. if 7bytes or less are transferred, all bytes are accepted. and if 9 bytes or more, the 9 th and later are ignored. note that the data should be in 8*n bits (n=integer number), otherwise it may cause malfunctions. and the sck should be ?0? when the req is changed. serial data format table 3-1 command data 1 b7 b6 b5 b4 b3 b2 b1 b0 0 soff bright stby hold rev table 3-2 command data 2 b7 b6 b5 b4 b3 b2 b1 b0 0 0 0 0 0 0 divide table 3-3 duty data b7 b6 b5 b4 b3 b2 b1 b0 1 * pwm register figure 1 command data transmission figure 2 duty data transmission b7 6 5 4 3 2 1 0 b7 6 5 4 3 2 1 0 req sck data cmd1 cmd2 b7 6 5 4 3 2 1 0 b7 6 0 b7 6 0 b7 6 req sc k dat a pwm register 0 1 6 7
- 8 - NJU6052 ver.2004-02-26 (5-2) sensor data read the data terminal becomes output state by setting the req terminal to ?1? after the command data transmission. and the sensor data is read out, synchronizing with the sck. the bit number corresponding to a selected register is ?1? and the others are ?0?, as shown below. figure 3 sensor data read (rev=0, pwm register4 selected) req sck data b7 0 1 2 3 4 5 6 7 command data (input) sensor data (output) (5-3) soff and bright by setting ?1? at the soff bit, the luminance sensor control is disabled and the pwm duty is controlled by the bright bits, as shown below. table 4 soff and bright soff bright rev pwm register pwm register0 pwm register1 pwm register2 pwm register3 pwm register4 pwm register5 pwm register6 0 - 0 pwm register7 000 pwm register0 001 pwm register1 010 pwm register2 011 pwm register3 100 pwm register4 101 pwm register5 110 pwm register6 1 111 - pwm register7 note 1) when soff=?0?, luminance sensor control is enabled and pwm register is selected according to sens voltage. note 2) for the information on the relation between sens voltage and pwm register, refer to ?dc electrical characteristics?. (5-4) stby by setting ?1? at the stby bit, the NJU6052 goes into the standby mode, as follows. - dc/dc converter, oscillator, reference voltage generator, and power supply for sensor are halted. - the contents of pwm register are maintained. - luminance sensor control circuit is initialized.
-9- NJU6052 ver.2004-02-26 (5-5) hold by setting ?1? at the hold bit, the selected pwm register is held and the luminance sensor control cannot be used. in other words, this setting works so that the luminance of the leds doesn?t change even if the sens voltage changes. the selection is initialized to the pwm register 0 by the reset. and when the standby is released, the selection is initialized to the pwm register 0 at rev=?0? or the pwm register 7 at rev=?1?. (5-6) rev by setting ?1? at the rev bit, the correspondence between the pwm register and sens voltage is reversed. table 5 rev rev pwm register pwm register0 pwm register1 pwm register2 pwm register3 pwm register4 pwm register5 pwm register6 0 pwm register7 pwm register7 pwm register6 pwm register5 pwm register4 pwm register3 pwm register2 pwm register1 1 pwm register0 (5-7) divide by setting the divide bits, the sensor-sampling-time (t sens ) and pwm frequency (f pwm ) are changed. note that these parameters are varied depending on the oscillation frequency (f osc ). the formula (2) gives the sensor-sampling-time. table 6 sensor sampling time f osc divide n 100khz 200khz 400khz 800khz 00 0 1.311 0.655 0.328 0.164 01 1 2.621 1.311 0.655 0.328 10 2 5.243 2.621 1.311 0.655 11 3 10.486 5.243 2.621 1.311 () (sec) 2 17 osc n sens f t + = --- formula (2) unit : sec
- 10 - NJU6052 ver.2004-02-26 and, the formula (3) gives the pwm frequency. table 7 pwm frequency f osc divide n 100khz 200khz 400khz 800khz 00 0 195.3 390.6 781.3 1562.5 01 1 97.7 195.3 390.6 781.3 10 2 48.8 97.7 195.3 390.6 11 3 24.4 48.8 97.7 195.3 note) pwm frequencies written in bold or neighbors are recommended, otherwise it might cause led flickering. (6) level shifter the level shifter allows the communication with the mpu working at the power supply voltage lower than the v dd . apply the mpu power-supply-voltage on the v ddl terminal. the voltage range is: 1.8v< v dd l< 3.6v . (7) reset by setting the rstb pin to ?l?, the NJU6052 is initialized into the following default status. table 8 reset register data default status rev 0 refer to table 5 hold 0 sensor sampling is enabled stby 0 standby off bright 000 soff 0 luminance sensor control is enabled divide 00 pwm register0-7 000000 pwm duty 0% (led off) (8) temperature compensation the reference voltage (v ref ) generator has temperature compensation, which suppresses the characteristic degradation of leds at high temperatures. refer to ?i led vs. temperature? shown in the ?dc electrical characteristics?. ) ( 2 64 1 ) 3 ( hz f f n osc pwm + ? = unit : hz --- formula (3)
-11- NJU6052 ver.2004-02-26 (9) applications information (9-1) pwm duty and led current the average led current is programmed with the single resistor r led and the pwm duty, as shown in formula (4). (9-2) inductor selection formula (5) is used to choose an optimum inductor, as shown below: : power conversion efficiency (= 0.7 to 0.8) the power supply voltage v in may fluctuate in battery-powered applications. for this reason, the minimum voltage should be applied to the v in in formula (5). the NJU6052 has about 200ns of delay time (t delay ), which is defined as the period from the reach of the current limit 720ma to the mos-switch-off. the t delay may cause an overshoot-inductor-current, which is called the peak current i l,peak , and calculated by formula (6). therefore, it is recommended that an inductor with a rating twice of the i l,peak and a low dcr (dc resistance) be used for high efficiency. vds : drain-source voltage of the mos switch (=i limit *r on ) vin (max) : maximum of v in voltage (9-3) diode selection a schottky diode with a low forward-voltage-drop and a fast switching-speed is ideal. and the diode must have a rating greater than the output voltage and the output current in the system. (9-4) capacitor selection a low esr (equivalent series resistance) capacitor should be used at the output to minimize output ripples. a multi-layer ceramic capacitor is the best selection for the NJU6052 application because of not only the low esr but its small package. a ceramic capacitor as the input decoupling-capacitor is also recommended and should be placed as close to the NJU6052 as possible. led ref r v duty = ? = led(max) led(max) led(avg) i 100 i i --- formula (4) delay ds (max) in limit peak , l t l v v i i ? ? ? ? ? ? ? ? ? ? + = osc limit led in out f i i v v l ? ? ? ? ? ? ? ? ? ? ? = 2 2 --- formula (5) --- formula (6)
- 12 - NJU6052 ver.2004-02-26 absolute maximum ratings ta = 2 5 c parameters symbol conditions ratings unit note v dd power supply v dd -0.3 to +6 v v ddl power supply v ddl -0.3 to v dd v input voltage v in1 cx/tclk, ref, fb, sens terminals -0.3 to v dd +0.3 v input voltage v in2 req, data, sck, rstb te r m i n a l s -0.3 to v ddl +0.3 v switch voltage v sw sw terminal +18.0 v 3 power dissipation pd t.b.d. mw 4 5 operating temperature t opr -40 to +85 c storage temperature t stg -55 to +125 c note1) all voltages are relative to v ss = 0v reference. note2) do not exceed the absolute maximum ratings, otherwise the stress may cause a permanent damage to the ic. it is also recommended that the ic be used in the range specified in the dc electrical characteristics, or the electrical stress may cause mulfunctions and affect the reliability. note3) the switch voltage v sw is the highest voltage in the system. this voltage must not exceed the absolute maximum rating. v sw =v f (led) x n(led) +v f (d1) +v ref v f (led) :forward voltage of led n(led) :the number of leds v f (d1) :forward voltage of diode d1 for instance, when v f (led) = 3.6v, n(led)=4pcs, v f (d1)=0.3v, v ref =0.6v(typ), v sw = 3.6v x 4 + 0.3v + 0.6v = 15.3v. note4) mounted on the glass epoxy board (50mm x 50mm x 1.6mm) note5) mounted on the board specified by eia/jedec (2-layer fr-4, 76.2mm x 114.3mm x 1.6mm)
-13- NJU6052 ver.2004-02-26 dc electrical characteristics v ddl =1.8 to 3.6v, v dd =3.0 to 5.5v, ta=-40 to 85 c ratings parameters symbol conditions min. typ. max. unit note v dd power supply v dd 3.0 5.5 v v ddl power supply v ddl 1.8 3.6 v output current i out 60 ma 1 reference voltage v ref ta = 2 5 c dc/dc converter off 0.558 0.60 0.642 v 2 operating current i opr fosc=350khz 1.0 1.4 ma 3 standby current i stby 1 ua 4 v so power supply v so 2.23 2.40 2.57 v 5 pwm register0 selected voltage v d0 sens terminal, rev=0 0 0.0055v so v pwm register1 selected voltage v d1 sens terminal, rev=0 0.015v so 0.0185v so v pwm register2 selected voltage v d2 sens terminal, rev=0 0.030v so 0.040v so v pwm register3 selected voltage v d3 sens terminal, rev=0 0.060v so 0.090v so v pwm register4 selected voltage v d4 sens terminal, rev=0 0.110v so 0.180v so v pwm register5 selected voltage v d5 sens terminal, rev=0 0.220v so 0.360v so v pwm register6 selected voltage v d6 sens terminal, rev=0 0.440v so 0.720v so v pwm register7 selected voltage v d7 sens terminal, rev=0 0.880v so v so v input ?l? level v il sck, data, req, rstb terminals 0 0.2v ddl v input ?h? level v ih sck, data, req, rstb terminals 0.8v ddl v ddl v output ?l? level v ol data terminals v ddl =1.8v, i ol =0.4ma 0.2v ddl v output ?h? level v oh data terminals v ddl =1.8v, i oh = - 0.04ma 0.8v ddl v oscillation frequency f osc v dd =3v, cx=82pf 210 350 490 khz oscillation duty d osc v dd =3v, cx=82pf 77 82 87 % 6 switch current limit i limit sw terminal, v dd =4.2v v fb >v ref /2, ta=25 c 610 720 825 ma switch on voltage v ds (on) sw terminal, v dd =4.2v i sw =720ma, ta=25 c 1 1.4 v over voltage protection v ovp v out terminal 17.5 v
- 14 - NJU6052 ver.2004-02-26 note1) output current test conditions test command b7 b6 b5 b4 b3 b2 b1 b0 command data 1 0 1 0 0 0 0 0 0 command data 2 0 1 0 0 0 0 0 0 duty data 1 * 1 1 1 1 1 1 *: ?don?t care? test circuit v dd :5v d1 :schottky diode l1 :10uh c1 :4.7uf c2 :1uf r led :30 ? r load :750 ? r1 :100k ? f osc :350khz / duty 82% nc v ss v ss v ss ref cx/tclk nc nc sw sw sw v out fb nc nc test nc v dd v ddl req nc nc v so sens rstb sck data nc c2 c1 controller f osc r led d1 l1 r1 a r load
-15- NJU6052 ver.2004-02-26 note2) temperature compensation the reference voltage (v ref ) generator has temperature compensation, which suppresses the characteristic-degradation of leds at high temperatures. the v ref is regulated to 0.6v typical in the temperature range up to 45c, and gradually decreases as the ambient temperature rises in the range higher than 45c. vref vs temperature 0.0 0.5 1.0 -50 -25 0 25 50 75 100 temperature[ ] vref[v] iled vstemperature 0 10 20 30 -50 -25 0 25 50 75 100 temperature[ ] iled[ma] rled=30 rled=40 figure 4 vref vs. temperature figure 5 iled vs. temperature
- 16 - NJU6052 ver.2004-02-26 note3) operating current test conditions test command b7 b6 b5 b4 b3 b2 b1 b0 command data 1 0 1 0 0 0 0 0 0 command data 2 0 1 0 0 0 0 0 0 duty data 1 * 1 1 1 1 1 1 *: ?don?t care? note4) standby current test command b7 b6 b5 b4 b3 b2 b1 b0 command data 1 0 * * * * 1 * * command data 2 0 1 0 0 0 0 0 0 *: ?don?t care? test circuit (operating current, standby ciurrent) led :v f =3.6v, i led =20ma d1 :schottky diode l1 :10uh c1 :4.7uf c2 :1uf r led :30 ? r1 :100k ? f osc :350khz / duty 82% nc v ss v ss v ss ref cx/tclk nc nc sw sw sw v out fb nc nc tes t nc v dd v ddl req nc nc v so sens rstb sck data nc c2 controller f osc r led d1 l1 r1 a c1
-17- NJU6052 ver.2004-02-26 note5) v so power supply test condition test command b7 b6 b5 b4 b3 b2 b1 b0 command data 1 0 1 1 1 1 0 0 0 command data 2 0 1 0 0 1 0 0 0 test circuit led :v f =3.6v, i led =20ma d1 :schottky diode l1 :10uh c1 :4.7uf c2 :1uf r led :30 ? r1 :100k ? r2 :1k ? f osc :350khz / duty 82% r2 c1 nc v ss v ss v ss ref cx/tclk nc nc sw sw sw v out fb nc nc test nc v dd v ddl req nc nc v so sens rstb sck data nc c2 controller f osc r led d1 l1 r1 v
- 18 - NJU6052 ver.2004-02-26 note6) oscillator the built-in oscillator incorporates a reference power supply, so its frequency is independent from the v dd . the frequency is varied by the external capacitor cx, as shown below. (reference but not guaranteed) fosc vs cx 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 cx(pf) fosc(khz) figure 7 f osc vs. cx
-19- NJU6052 ver.2004-02-26 ac electrical characteristics v ddl =1.8 to 3.6v, v dd =3.0 to 5.5v, ta=-40 to 85 c ratings parameters symbol min. typ. max. unit sck clock cycle t sccy 1.0 - - us ?h? level t wsch 400 - - ns sck clock width ?l? level t wscl 400 - - ns req hold time t reh 800 - - ns data set-up time t dis 400 - - ns data hold time t dih 400 - - ns output data delay time cl=20pf t d0 - - 200 ns req set-up time t res 400 - - ns req high level width t wreh 800 - - ns req,sck,data rising time t r - - 100 ns req,sck,data falling time t f - - 100 ns rstb pulse width t rsl 1.0 - - us serial input timing serial output timing reset input timing t res t wscl t wsch t re h t wreh data t di s t di h b7 b6 bn b5 b0 t sccy sck req 0.3v dd 0.3v dd t rsl rstb t res t wscl t wsc h t re h data t d o b7 b6 bn b5 b0 t sccy sck req
- 20 - NJU6052 ver.2004-02-26 typical performance 1. oscillation frequency figure 8 output voltage vs. frequency @vdd=3v,iload=30ma,duty=82% 0 2 4 6 8 10 12 14 16 18 100 200 300 400 500 600 700 800 frequency[khz] output voltage[v] l=4.7uh l=6.8uh l=10uh @vdd=3v,iload=60ma,duty=82% 0 2 4 6 8 10 12 14 16 18 100 200 300 400 500 600 700 800 frequency[khz] output voltage[v] l=4.7uh l=6.8uh l=10uh @vdd=5v,iload=30ma,duty=82% 0 2 4 6 8 10 12 14 16 18 100 200 300 400 500 600 700 800 frequency[khz] output voltage[v] l=4.7uh l=6.8uh l=10uh @vdd=5v,iload=60ma,duty=82% 0 2 4 6 8 10 12 14 16 18 100 200 300 400 500 600 700 800 frequency[khz] output voltage[v] l=4.7uh l=6.8uh l=10uh
-21- NJU6052 ver.2004-02-26 2. load current figure 9 output voltage vs. load current figure 10 efficiency vs. load current @vdd=3v,l=10uh,duty=82% 0 2 4 6 8 10 12 14 16 18 0 102030405060708090100 load current[ma] output voltage[v] f=210khz f=350khz f=490khz @vdd=5v,l=10uh,duty=82% 0 2 4 6 8 10 12 14 16 18 0 102030405060708090100 load current[ma] output voltage[v] f=210khz f=350khz f=490khz @vdd=3v,l=10uh,duty=82% 0 10 20 30 40 50 60 70 80 90 100 0 102030405060708090100 load current[ma] efficiency[%] f=210khz f=350khz f=490khz @vdd=5v,l=10uh,duty=82% 0 10 20 30 40 50 60 70 80 90 100 0 102030405060708090100 load current[ma] efficiency[%] f=210khz f=350khz f=490khz
- 22 - NJU6052 ver.2004-02-26 3. typical performance test circuit test command b7 b6 b5 b4 b3 b2 b1 b0 command data 1 0 1 0 0 0 0 0 0 command data 2 0 1 0 0 0 0 0 0 duty data 1 * 1 1 1 1 1 1 * :?don?t care? test circuit d1 : schottky diode l1 :10uh c1 :4.7uf c2 :1uf r led :4.2k ? r load :100k ? r1 :100k ? nc v ss v ss v ss ref cx/tclk nc nc sw sw sw v out fb nc nc test nc v dd v ddl req nc nc v so sens rstb sck data nc c2 c1 controller f osc r led d1 l1 r1 r load v
-23- NJU6052 ver.2004-02-26 typical application circuit [caution] the specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. the application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights. nc v ss v ss v ss ref cx/tclk nc nc sw sw sw v out fb nc nc test nc v dd v ddl req nc nc v so sens rstb sck data nc c2 c1 controller r led d1 l1 r1 r2 c3 photo sensor

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