1/8 L9474 march 2005 1 features high side field driver thermal protection field driver short circuit protection rvc interface overvoltage protection complex diagnostics load response control 2 description the L9474 is a monolithic multifunction generator voltage regulator intended for use in automotive ap- plications. this device regulates the output of an automotive generator by controlling the field winding current by means of a variable frequency pwm high side driver. the setpoint voltage reference is selected by the en- gine control unit via rvc protocol. all silicon voltage regulator figure 2. schematic diagram field (rotor) starter battery stator asvr loads rectifier bridge f m f+ v go p filter c 82nf g to ecm l to ecm to bcm d02at508 fi gure 1. p ac k age table 1. order codes part number package L9474 multiwatt8 multiwatt8 rev. 1
L9474 2/8 table 2. pin description table 3. absolute maximum ratings figure 3. pin connection (top view) table 4. thermal data n pin function 1 p phase sense input 2 l warning terminal output and ecm pwm input 3f m field monitor output 4 reserved reserved 5gnd 6 filter regulation loop filter 7 f+ field high side driver output 8v go generator output sense and voltage supply to L9474 symbol parameter value unit v s transient supply voltage (load dump) 40 v i o output current capability internally limited a p tot power dissipation (@t j = 150c, i field = 6a) 6 w v rev reverse voltage (see fig.1) -2.5 to -6 v symbol parameter value unit t j junction temperature -40 to 150 c t stg storage temperature -50 to 150 c t sd thermal shut down 175 15 c r th j-case thermal resistance junction to case 1.5 c/w 1 2 3 4 5 6 7 d02at509 8 v go f+ filter gnd reserved f m l p
3/8 L9474 table 5. electrical characteristcs (t j -35c to +150c unless otherwise specified) notes: 1. 16 volts is the maximum operating voltage. 2. stand-by current measured with l, fm open; f connected to gnd; p open or tied to gnd. 3. when the voltage sensed at vgo terminal is above vov the minimum field duty-cycle will be 0 %. figure 4. reverse b+ test circuit symbol parameter test condition min. typ. max. unit v os operating supply voltage 8 16 1 v i sb stand-by current 2 v go = 12.6v, t case -35 to +80 c 400 a v go = 12.6 v, 80 25c 850 mv i flim field limit current f shorted to gnd, t case < = 25c 9 a f shorted to gnd, t case = 150 c 6 a v f field discharge rectifier i f =6a, t case = 25 c 1.85 v i r diode reverse current v r = 16 v 1 ma f osc oscillation frequency during lrc operation 340 400 460 hz mfdc minimum field duty-cycle v(v go ) < v ov 3 6.25 % r fm impedance @ f m pin impedance between fm and f+ 0.8 2.5 k ? 1.8 ? field c 82nf asvr f m f lp filter v go f g d02at510 power supply 6v +- power supply 2.5v -+
L9474 4/8 figure 5. setpoint voltage vs. l terminal signal table 6. diagnostic (t j -35c to +150c unless otherwise specified) note: 4. when the vgo voltage overcomes this value the mfdc is cancelled table 7. fault the following table lists the conditions t hat cause the fault driver to function (l terminal now switching be-tween 0v and vlsat. to prevent l flicker, specific faults are required to be present for tdelay seconds be-fore the fault driver is activated. this delay is indicated in the table. symbol parameter test condition min. typ. max. unit v ov overvoltage 4 16.5 22 v v lsat l saturation voltage i l = 50 ma 1.35 v t delay fault indication delay time 0.935 1.1 1.265 s conditions delay 1. key-on (rvc pwm signal acknowledgement) no 2. phase voltage < vp2 and v go < setpoint yes
5/8 L9474 table 8. regulation features notes: 5. a 128hz pwm signal applied to l input, higher than this threshold, will turn on the device. 6. this threshold on the phase signal is used to detect the phase frequency, fifr, for the initiation of field regulation. 7. this threshold on the phase signal is used to sense the presence of the phase for fault detection purposes. furthermore, to prevent the loss of phase signal, a 31.25% duty cycle is applied to field output when phase drops below vp2 and vgo is above setpoint. 8. this is the time duration the L9474 takes to rump up from 0 % to 100% duty cycle in response to an increased load on the gen - erator. the lrc ratio is set 1:4 and the vreg comparator status is latched at foundamental frequency rate. symbol parameter test condition min. typ. max. unit v lon lamp term turn on 5 threshold fl = 128hz +/-5% 0.65 0.9 1.15 v i lon vl = 0.65v 0.3 1.5 ma v p1 initiation of regulation detection phase voltage threshold 6 i p = 1ma (sinking current) 0.35 v v p2 fault detection phase voltage threshold 7 789v i p sinking current @ p terminal v p = 1.5v 0.5 1 1.8 ma f ifr initiation of field regulation frequency 72 hz fsdf field strobe duty factor @ "power up" with f phase < f ifr 12.5 % lrc load response control rate 8 2.125 2.5 2.875 s f lrc lrc transition frequency lrc disabled above this value 263 310 357 hz ? gnd difference between ecm & alternator ground -0.2 0.2 v
L9474 6/8 3 package information figure 6. multiwatt8 mechanical data & package dimensions outline and mechanical data 0043674 f * dim. mm inch min. typ. max. min. typ. max. a50.197 b 2.65 0.104 c1.60.063 e 0.49 0.55 0.019 0.022 f 0.78 0.85 0.030 0.033 f1 0.68 0.75 0.027 0.029 g 2.40 2.54 2.68 0.094 0.10 0.105 g1 17.64 17.78 17.92 0.69 0.70 0.71 h1 19.6 0.772 h2 20.2 0.795 l 20.35 20.65 0.80 0.81 l2 17.05 17.20 17.35 0.67 0.68 0.68 l3 17.25 17.5 17.75 0.679 0.689 0.699 l4 10.3 10.7 10.9 0.406 0.421 0.429 l5 15.45 15.75 0.61 0.62 l5* 15.05 15.35 0.59 0.60 l7 2.65 2.9 0.104 0.114 s 1.9 2.6 0.075 0.102 s1 1.9 2.6 0.075 0.102 u 0.40 0.55 0.015 0.022 z 0.70 0.85 0.028 0.034 dia1 3.65 3.85 0.144 0.152 l5 = with wedged frame std. l5* = with wedged frame anchor holes. multiwatt8 (floating)
7/8 L9474 4 revision history table 9. revision history date revision description of changes march 2005 1 first issue
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