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| ta8473f/fg/fn/fng 2006-3-2 1 toshiba bipolar linear integrat ed circuit silicon monolithic ta8473f/fg,ta8473fn/fng fan motor driver ic the ta8473f/fg and ta8473fn/fng are fan motor driver ics. the output current is 0.4 a (ave. ) and all functions needed for fan motor driving have been incorporated into 1 chip. these are provided with the functi on to automatically change the motor speed by detecting ambient temperature through the externally mounted thermistor. furthermore, the ta8473f/fg and ta8473fn/fng are provided with the noise reduction terminal , the fg terminal to output pulses proportional to the moto r speed and the rd terminal to detect the motor status. features z built ? in automatic self rotation recovery circuit after release of motor locking. z thermal shutdown circuit incorporated. z operating voltage : 6~13.8 v z 2 kind of speed of full ? speed and half ? speed are variable according to ambient temperature. z speed change point temperatur e is externally settable. ta8473f/fg ta8473fn/fng weight: ssop16-p-225-1.00a: 0.14g (typ.) ssop16-p-225-0.65b: 0.07g (typ.) ta8473fg/fng: the ta8473fg/fng is a pb-free product. the following conditions apply to solderability: *solderability 1. use of sn-37pb solder bath *solder bath temperature = 230c *dipping time = 5 seconds *number of times = once *use of r-type flux 2. use of sn-3.0ag-0.5cu solder bath *solder bath temperature = 245c *dipping time = 5 seconds *the number of times = once *use of r-type flux
ta8473f/fg/fn/fng 2006-3-2 2 block diagram pin function pin no. symbol functional description 1 v cc power voltage supply terminal. 2 b1 noise reduction capac itor connection terminal. 3 out1 output terminal. 4 gnd gnd terminal. 5 gnd gnd terminal. 6 out2 output terminal. 7 b2 noise reduction capac itor connection terminal. 8 th thermistor connection terminal. 9 rd rotation detect output terminal. 10 fg rotation speed output terminal. 11 sc lock protect time constant determined terminal. 12 hs half ? speed determined terminal. 13 r ref reference resistor connection terminal. 14 h ? hall input terminal. 15 h + hall input terminal. 16 nc non connection. ta8473f/fg/fn/fng 2006-3-2 3 half ? speed system to lower the motor speed, ta8473f/fg and ta8473fn/fng set the off ? time during the output timings (fig.1). starting the mult ivibrator (mmv) enables the off ? time. the off ? time is set by the time constant of capacitor ch connected to the hs terminal and ic internal resistor rh. a thermistor can also be used to control off ? time depending on the temperature. (1) determining ch the mmv operation can be monitored through the hs terminal. about 100 k ? rh is connected between v cc and hs, generating a transient with the external ch. the maximum peak level value is set to about 5 v and the bottom level to about 1 v. the off ? time is determined as follows : 1 5 1 v og chrh = t cc - - l for example, at ch = 0.1 f, rh = 100 k ? , and v cc = 12 v, off ? time is about 4.4 ms. since rh is an internal resistor, a fluctuation of 30% is permitted. the temperature characteristic is 0.5% / c. (2) determining off ? time if approximately the same off ? time (1~1.3) is set for the on timing when the motor is running at full speed, a number of rotations decreases to about half. as the coefficient depends on the motor, determine the off ? time value by experimenting. the number of rotations can be set to any value. howe ver, if the value is too low, the motor can be started but not run stably. (3) detecting temperature and controlling rotations ta8473f/fg and ta8473fn/fng compare the th terminal thermistor and the value of the resistor externally connected to the r ref terminal, and alters the off ? time. changes in off ? time can be made by altering the peak operation level of mmv. that is, ta8473f/fg and ta8473fn/fng internally apply a reference current of 100 a to the r ref terminal and generate at the th terminal a reference voltage of 1 v at r ref = 10 k ? . the peak level of mmv is controlled using the difference between th e current at the th terminal determined using the thermistor resistance, and another internal reference current. fig. 1 ta8473f/fg/fn/fng 2006-3-2 4 the peak level can be represented as follows : v peak = 5 ? 240 k ? (1 ref1 r ref / r vr ? 1 ref2 ) here, 1 ref1 = 1 ref2 = 100 a typ. r vr = r th + r a in addition, only positive values within parentheses ( ) are valid. the value of v peak is between 1 v and 5 v. the thermistor resistance, r th , is generally shown as follows : r th (ta) = ro expb (1 / ta ? 1 / to) ro : resistance ( ? ) when reference temperatur e to (normally, 25c= 298k) ta : ambient temperature (k) b : characteristic temperature (k) as the above equation shows, the thermistor has a negative temperature characteristic for ambient temperature, ta. the resistance drops at high temp erature. using this charac teristic, lowering the v peak value at high temperature runs the motor at full speed ; raising the value at low temperature reduces the number of fan rotations with the maximum off ? time. the number of rotations begins to increase from the minimum when r vr r ref , reaching the motor?s full speed when r vr is about 0.85 r ref . ta8473f/fg/fn/fng 2006-3-2 5 fg and rd outputs both the fg and rd outputs ar e the open collector outputs. the fg output is pulse proportional to the number of re volutions (the cycle is the same as out b) and the rd output is at the gnd level (actually, at vsat (rd) level) when the motor is being dr iven and the rd output at the potential level that is to be applied to the rd termin al as shown in fig.2 is outp ut when the motor is kept restrained. automatic self rotation recovery circuit if the rotation of the fan motor is forced to stop by any physical power, the driving coil may be burnt as inducing voltage caused when the motor is running di sappears and large current flows to the driving coil. therefore, it becomes necessary to pr ovide the fan motor with a circuit to prevent the drivin g coil from being burned by detecting the forced stop of the motor rotati on from the outside by some method and a circuit to automatically rotate the motor when it is released from the restraint. the ta8473f/fg and ta8473fn/fng are ics that have cleared the above problems by the burning preventive automatic return circuit. fig. 2 ta8473f/fg/fn/fng 2006-3-2 6 this operation is shown in fig.2. the capacitor csc connected to the csc terminal is charged by the charging current isl and its potential rises as shown below : dt i c 1 = v sl sc when the motor is rotating, it is charged and discharged repeatedly by trigger pulse bu t if the motor rotation is physically restrained, csc discharge by trigger pulse is stopped and the potential further increases. during this period, current flows continuously to the motor. if vsc (osc potential) reaches vscu, discharge starts slowly and at the same time, the outp ut is turned off to cur off current flowing to the motor. when the vsc potential reaches vscl, the output is turned on to allo w current flow to the motor and torque is generated. as long as the motor rotation is kept restrained, this operation is repeated and the output is turned on / off at a ratio of nearly 1 : 5. by this operation, the motor is heated and cooled and its temperature rise can be suppressed to a certain level. if the motor is released from the above restraint, the motor is started to run again by the generated torque and is continuously rotated by the generated trigger pulse. function input output mode h + (15) h ? (14) out1 (3) out2 (6) mode 1 h l on off mode 2 l h off on ta8473f/fg/fn/fng 2006-3-2 7 absolute maximum ratings (ta = 25c) characteristic symbol rating unit output terminal breakdown voltage v cer 30 v operating supply voltage v cc (opr.) 13.8 v ave. i o (ave.) 0.4 output current peak i o (peak) 1.2 (note 1) a rd output current i rd 10 ma fg output current i fg 10 ma hall input voltage v hm 300 (note 2) mv f/fg 800 (note 3) power dissipation p d fn/fng 735 (note 3) mw operating temperature t opr ? 30~85 c storage temperature t stg ? 55~150 c note 1: t = 0.1 s note 2: t j = ? 25~150 c note 3: this value is obtained by 50 50 1.6 mm pcb mounting occupied in excess of 40% of copper area. electrical characteristics (ta = 25c, v cc = 12 v) characteristic symbol test cir ? cuit test condition min typ. max unit supply current i cc D v cc = 12 v, out1 ?on? D 7.0 12.0 ma v sat1 D i o = 0.2 a, t j = 25c D 0.9 1.1 output saturation voltage v sat2 D i o = 1.0 a, t j = 25c D 1.3 1.8 v discharge current i sl D D 0.2 0.5 1.0 a charge current i su D D 1.4 2.0 3.0 a discharge voltage v sl D D D 1.5 D v charge voltage v su D D D 4 D v time constant t sc D c = 0.22 f, on time D 0.25 D s automatic self rotation recovery circuit duty dr D D 3 5 8 hall input voltage v hm D D 10 50 300 mv hysterisis ? v h D D D 8 D mv offset voltage v ho D D D 0 D mv opereating dc potential cmr D D 0 D v cc ? 2 v hall amp. input bias current i in D D D 1 3.0 a rd output saturation voltage v sat (rd) D i rd = 5 ma D 0.2 0.4 v fg output saturation voltage v sat (fg) D i fg = 5 ma D 0.2 0.4 v terminal voltage v th D r th = 10 k ? 0.7 1 1.5 v full speed r th (fs) D r ref = 10 k ? D 6 D k ? variable speed half speed r th (hs) D r ref = 10 k ? D 10 D k ? termal shutdown operating temperature t sd D D 150 D D c ta8473f/fg/fn/fng 2006-3-2 8 application circuit ta8473f/fg/fn/fng 2006-3-2 9 package dimensions weight : 0.14 g (typ.) ta8473f/fg/fn/fng 2006-3-2 10 package dimensions weight : 0.07 g (typ.) ta8473f/fg/fn/fng 2006-3-2 11 notes on contents 1. block diagrams some of the functional blocks, circuits, or constants in the block diagram may be omitted or simplified for explanatory purposes. 2. equivalent circuits the equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory purposes. 3. timing charts timing charts may be simplified for explanatory purposes. 4. application circuits the application circuits shown in this document are provided for reference purposes only. thorough evaluation is required, especially at the mass production design stage. toshiba does not grant any license to any industrial property rights by providing these examples of application circuits. 5. test circuits components in the test circuits are used only to obtain and confirm the device characteristics. these components and circuits are not guaranteed to prevent malfunction or failure from occurring in the application equipment. ic usage considerations notes on handling of ics [1] the absolute maximum ratings of a semiconductor de vice are a set of ratings that must not be exceeded, even for a moment. do not exceed any of these ratings. exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result injury by explosion or combustion. [2] use an appropriate power supply fuse to ensure that a large current does not continuously flow in case of over current and/or ic fa ilure. the ic will fully break down when used under conditions that exceed its absolute maximum ratings, when the wiring is routed improperly or when an abnormal pulse noise occurs from the wiring or load, caus ing a large current to continuously flow and the breakdown can lead smoke or ignition. to minimize the effects of the flow of a large current in case of breakdown, appropriate settings, such as fuse ca pacity, fusing time and in sertion circuit location, are required. [3] if your design includes an inductive load such as a motor coil, incorporate a protection circuit into the design to prevent device malfunction or breakdown caused by the current resulting from the inrush current at power on or the negative current resulting from the back electromotive force at power off. ic breakdown may cause injury, smoke or ignition. use a stable power supply with ics with built-in protection functions. if the power supply is unstable, the protection function may not operate, causing ic breakdown. ic breakdown may cause injury, smoke or ignition. [4] do not insert devices in the wrong orientation or incorrectly. make sure that the positive and negative terminals of power supplies are connected properly. otherwise, the current or power consumption may exceed the absolute maximum rating, and exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result injury by explosion or combustion. in addition, do not use any device that is applied the current with inserting in the wrong orientation or incorrectly even just one time. ta8473f/fg/fn/fng 2006-3-2 12 points to remember on handling of ics (1) thermal shutdown circuit thermal shutdown circuits do not necessarily prot ect ics under all circumstances. if the thermal shutdown circuits operate against the over temperature, clear the heat generation status immediately. depending on the method of use and usage conditions, such as exceeding absolute maximum ratings can cause the thermal shutdown circuit to not operate properly or ic breakdown before operation. (2) heat radiation design in using an ic with large current flow such as power amp, regulator or dr iver, please design the device so that heat is appropriately radiated, not to exceed the specified junction temperature (t j ) at any time and condition. these ics generate heat even during normal use. an inadequate ic heat radiation design can lead to decrease in ic life, de terioration of ic characteristics or ic breakdown. in addition, please design the device taking into considerate the effect of ic heat radiation with peripheral components. (3) back-emf when a motor rotates in the reverse direction, stops or slows down abruptly, a current flow back to the motor?s power supply due to the effect of back- emf. if the current sink capability of the power supply is small, the device?s motor power supply and output pins might be exposed to conditions beyond maximum ratings. to avoid this problem, take the effect of back-em f into consideration in system design. ta8473f/fg/fn/fng 2006-3-2 13 |
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