HA13426 Three-Phase Motor Driver with Speed Discriminator Description The HA13426 power IC for driving the three- phase brushless motor of 5.25 inch-HDD (hard disk drive) includes a speed discriminator. It is possible to construct a servo system with by adding a quartz resonator and few external components. Because it uses a voltage drive system, it controls EMI (electro magnetic interference) noise from the motor driver. Features * Single-chip servo system * Large output current (3A) Digital servo system requires no adjustment. * The voltage drive system (not supply voltage control) causes almost no spike voltage at commutation which causes EMI in conventional systems * TFIL-level START/STOP termina] * Load-short brake at STOP mode * Built-in current limiter depresses maximum current at starting. * Frequency divide permits wide selection for quartz resonator. Block Diagram HA13426 (SP-23TA) Pin Arrangement : U Hall + In U Hall In V Hall + In V Hall -In W Hall + In W Hall - In W Out Open V Out Integrator Out U Out Integrator In Current Sense Speed Diseri. Out Filter Internal Reference GND OSC Out Mode Selact C) OSC In Injector START/STOP Ves (Top view) Ordering Information Type No. Package HA13426 SP-23TA HITACH! 72 Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300Table 1 External Components HA13426 Part No. Recommended Value Function Note Rio1, R102 1kQ Hall effect element bias 1 R103, Rio4, Rios 2.2 2 (0.5 W) Stability R106 1.8kOQ OSC bias 6 R107 1.2kQ Speed descrim. bias R108 470 Stability 6 Ri,R2 See functional description Integration constant Rs _ Current sense 3 C101, C102, C103 0.1 pF Stability 2 C104 20.1 pF Vec bypassing C106 10 pF AC coupling OSC Cioa, Cio9, C110 20.01 WF Stability Cin 4700 pF Stability 5 C1,C2 See functional description Integration constant 4 C3 See functional description Filter constant Xtal See functional description Resonator Notes: 1. Set R101 and R102 so that output voltage of more than 50 mVpp is applied to hail- effect elements. 2. Use capacitors for C101 to C103 which cause no 2nd resonance. Connect the common points of C101, C102, and C103 to the most stable of Vcc, GND, on the middle point of the coil (use non-polar capacitor when connecting them to the middle point of the coil). 3. Output current is limited as shown below by Rs value. limit = 0.56 V+10 % Ris(G) For example, output current is limited to 2.55 A+10 % at Rs=0.22 4. 1and C2 must be nonpolar. 5. Determine external components of Oscillator as shown below in accordance with the frequency range. HITACHI Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane. CA 94005-1819 (415) 589-8300 73HA13426 1.0 MHz = fosc <= 4.0 MHz 4.0 MHz < fosc < 8.0 MHz 0 (21%) Crystal 1.0 to 1.8k2 () 10pF | | (41%) Crystal 470Q = 1.0kQ 4,700pF Coane | 777 Functional Description Resonator Selection HA13426: The synchronous oscillating frequency, fosc, and the motor rotation speed N have the relationship; 60 mefosc 512 pm ae aneeeeeenenrreurnera nn era ed (1) where p is the number of motor poles and m is the dividing ratio of the divider. The mode select pin determines m (Table 2). Table 2 Dividing Ratio Mode Select m GND 1/16 Open 1/32 Vec 1/64 Table 3 shows sample values of fosc to rotate a 4- poles motor at 3600 rpm. Table 3 fose Examples Mode Select fose(MHz) GND 1.96608 Open 3.93216 Voc 7.86432 HA13431/432/432MP: The synchronous oscillating frequency fosc, and the FG frequency, {Fc, have the relationship; m*fosc Jong rrr rrrrssrrserrrsserntsssten (2) where m is the dividing ratio of the divider, and determined by one of the mode select pin (Table 4). fFG = Table 4 Dividing Ratio Mode Select m GND 1 Open 1/2 Vec 1/4 Determining Integration Constants Ri, R2, C1, and C2, and Filter Constant C3 Figure 1 is the block diagram showing motor speed control by the HA13426/431/432/432MP. The part enclosed by dotted lines denotes the [C, and Gi (S) and G2 (S) indicate an integrator transfer function and the transfer function from control amp to output, respectively. Since these iCs are driven by voltage, the motor coil impedance and the kick- back voltage are contained in the loop. @ HITACHI 74 Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 * (415) 589-8300HA13426 Load Kj (rpm) 160 { [2 Terque J.S No Error (%) (kg -cm) HA13426/43 1/432/432MP Kr I ' t 1 A Control (A) i Amp Integrator =. tT Gees) eM ai sy bag a4 zm (S) 2 ( 1 ( ) Ky ; Wee eee ee ee ee ee ee eee eee ; (VY) KENo 100 = s[ Kj=Transfer constant, 9.55 Kt=Torque constant (kg.cnvA) Ke=Kick-back constant {V/rppm) Kv=Speed discriminator gain (V/%} J=Moment of inertia (kg cm + sec?) Zm(S)=Motor coil impedance (Q) Gi (S)=Integrator transfer function Ge (S)=Transfer function from control amp to output No=Standard speed of rotation Figure 1 Block oem In Figure 1, when Ke*No = K S$) - _._.... 4 Ki 100 6 B(S) = Fm ay (KveGi(S)-G2xS) 100 (4) Ng rte ttettesseeeeeeesnsrenenee Then Figure 1 can be shown in Figure 2. Load + Torque C (kgeom) A(S) -() Error (%) B(S) -<? Figure 2 Simplified Block Diagram @ HITACHI Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300 75HA13426 On the other hand, Zm(S), Gi(S), and G2(S) are expressed as follows; Zmm(S)=RM(1+S/COM) seovscveveeveessesssssesesseerns (5) Gi(S) = ae a ceccssenessenuneseusnsitn (6) G2(S) = ae cscseuusansesseanareeenuanseseneviens (7) Then, (om = = sssuusaseseseusnsnnscncsasesesevisnnseeeveee (8) 1= aa veageusececcccesessausnteseessssessseeeeceeeosaateas (9) @2 = as ba cseesacceeseaseesssen sees cnceesesacseeraeesees (10) w3 = ae cessssssanesteesstneenecenanesssnsssnese (11) Gct_ and R3 are the internal constant of the IC. Substituting equations (5) to (11) into equation (4), BCS), gives B(S)= KT ( R2KvGcr1(1+@2/S) KENo) "Rm(1+S/am) Ri(1+S/o1)(1+S/w3) 100 _ R2KtTKvGcr 1+24+/S RiRm (1+S/am) (14+S/a1) (1+5/03) R2KvGcrtL > KeENo ) Ri 100 To control speed within a stable fashion, A(S) and BCS) must have the relationship shown in Figure 3. That is, the angular frequency of the crosspoint of A(S) and B(S), wo, should be between the angular frequency of the integrator, @1 and 2. assuming Determining wo: wo uses the value of 1/10 to 1/30 of the wm or the angular frequency of FG, arc, whichever is lower. In the HA13426, the angular frequency of the Hall-effect signal is used for wc, and the o has the value of 1/30 to 1/100 of wre. Calculating Ao from equation(3): Kj 100 we eensseesttetetcene 1 80-90 No (13) Designing Ri and R2 From Figure 3 and equation (12): R2_ Rm Ri KreKveGcr*Ao Each IC is designed with Kv and Gcrz as shown in Table 5. sees sessenseeeseeseeseee ee ( 14) Table 5 Ky and GctL Type Kv(V/%) GcTL(V/V) HA13426 0.03 16 typ HA13431 0.023 16 typ HA13432/MP 0.023 8 typ Smali Ri increases Ci and C2 and large Ri will cause speed error by the cutoff current of the speed discriminator and the input bias current of the integrator. Values of 10-56kQ are recommended. = 1,000b s 100 a z 10+ 1 l 1 10 @ (rad/sec} i 1,000 Figure 3 Stable Relationship of A(S) and 6(S) @ HITACHI 76 Hitachi America, Ltd. Hitachi Piaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300Determining (1,2 and 3: 12300 @2<wo/3 032300 Designing Ci, C2, C3: from equations (9), (10), (11), Ci=l/@1R2 C2=1/anR2 C3=1/w3R3 where the R3 is 22kQ. Using an External Clock As shown in Figure 4 an external clock can be provided at the OSC input pin. But applying too large an input causes mis-operation of the IC. Resistor Rs must be connected in series to control _ the current. HA13426 HA13426: Rs2>2.5(Vin-1.4)-1.5 (kQ) Rss7.5(1.4-Vit)-1.5 (kQ) A speed-up capacitor parallel to Rs should be considered. HA13431/432/432MP: Rs23.7(ViH-1.7}-2 (kQ) Rs$1.0(1.7-Vit}-2 (kQ) The input currents, hy and In, are restricted as follows and the external clock must have a larger driving capacity: Vin-1.4 HH = mH RsaRi (mA) i= 1.4Vit (mA) * RstRi m where Ri, the input resistance of OSC, is 1.5 kQ in HA13426 or 2 kQ in the others. Extermal Clock Vin | i Ra VIL O L. f 100pF OSC Input { VY Output Figure 4 External Clock Producing the Ready Signal As shown in Figure 5, an external comparator can produce the ready signal. Since the DC gain is extremely high (70dB or more), the rotation error, AN, when the ready signal Vr becomes high is determined by the accuracy of the speed discriminator without the influence of the comparator window. Open collector output type comparators are recommended. @ HITACHI Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300 77HA13426 +5 V HAI7903PS V1 10kQ ij_____--- 3.5V pC) , Ready Signal 10k2 VA = : Integrator + Output i V2 28V Figure 5 Ready Signal Table 5 Absolute Maximum Ratings (Ta = 25 C) ttem Symbol Ratings Unit Note Supply voltage Vec 15 Vv 1 Input voltage VIN 0 to Vee V 2 Output current lo 3 A Power dissipation PT 25 Ww 3 Junction temperature Tj 150 C Operating junction temperature range Tjop -20 to +125 C Storage temperature range Tstg 55 to +125 C The absolute maximum ratings are limiting values, to be applied individually, beyond which the device may be permanently damaged. Functionai operation under any of these conditions is not guaranteed. Exposing a circuit to its absolute maximum rating for extended periods of time may atfect the device's reliability. Notes: 1. Recommended operating voltage: Veco = 12 Vt15 % (10.2 to 13.8V) 2. Applied to Hall-effect element amp, mode select input. Maximum input voltage at start/stop is 6 V. 3. Thermal resistance: Gj-1 < 3C/W Oj-a < 40C/W @ HITACHI 78 Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300HA13426 Table 6 Electrical Characteristics (Ta=25C, Vcc=12 V) Item Symbol Min Typ Max Unit Test Condition Total Supply vurrent Iso 50 70 mA S/S=2.0V Is 55 75 mA S/S=0.8 V, Ri=Open Over-temperature Tsd 150 ~ Shutdown protection : Thys 20 C Hysteresis Hall- Input bias current IHB _ 2 10 BA VH=6.0V effect element !nput common mode Vu 20 10 02 amp voltage range Voltage gain Gvk 10 dB Output Quiescent output Va 53 59 65 V stage voltage Phase difference AVa _ _ +03 V Saturation voltage Veesat1 = 24 32 #V lo=2A (Note) Output impedance Ro 02 Q lo=0.4A Control = Internal ref. voltage = Vref 30 32 34 #V am P Voltage gain Geri 21 24 27 dB (CTL amp to output) Difference of gain AG +2 dB Integrator Input bias current ip 40.1 yA Output voltage swing A _ 07 V lo=0.3 mA A _ 07 - V lo=-0.3 mA Speed Qutput voltage swing Von 58 6.1 _ V lo=0.3 mA discrimi- Cutoff current loft _ +0.1 pA Charge pump off Operating frequency _ fe.k 60 _ 250 ~=-kHz Count number N 1024. Start/stop input high voltage Vin 20 V Stop Input low voltage Vib _ 08 V Start Input high current [iH -0.15 -05 mA VWH=2.0V Input low current he -0.2 -05 mA VL=0.8V @ HITACHI Hitachi America, Ltd. e Hitachi Plaza 2000 Sierra Point Pkwy. * Brisbane, CA 94005-1819 (415) 589-8300 79HA13426 Electrical Characteristics (Ta=25C, Vcc=12 V) (cont) Item Symbol Min Typ Max Unit Test Condition Current Reference voltage 0.52 0.56 060 V limiter Mode 1/16 division input Vii16 _ 08 V select voltage 1/32 division input V1132 _ 63 V Open voltage 1/64 division input = Vive4 H2 V voltage 1/16 division input 1116 -0.63 -13 mA Vnn=OV current 1/64 division input 11/64 _ 10 #15 mA Vin=12V current Oscillator Operating frequency _ fosc _ 8.0 MHz Note: Sum of upper and lower transistor saturation voltages U Out V Out W Out Hall-Effect 0 Element Amp Input S< 120] 120|120 .9V 5.9V 5.9V Cace J Figure 6 Timing Waveform @ HITACHI 80 Hitachi America, Ltd. Hitachi Plaza 2000 Sierra Point Pkwy. Brisbane, CA 94005-1819 (415) 589-8300