ordering number : en4927 d2094th (ot) 5-3438 no. 4927-1/17 overview the STK672-010 is a 4-phase stepping motor driver ic that adopts power mosfet for its output stage and that uses a unipolar fixed-current chopper scheme. since the STK672-010 includes a built-in 4-phase distribution controller, the stepping motor driver circuit and the control scheme can be simplified, and the stepping motor driver circuit structure can be standardized. the STK672-010 provides high torque, low vibration, and rapid response based on a w1-2 phase excitation drive scheme. the motor current is voluntary set from externals. since, compared to the earlier stk6770 series, the STK672-010 has a smaller package size and reduced drive power dissipation (reduced by 70% over previous products), it provides a wider operating power supply voltage range. applications send/receive stepping motors in facsimile equipment stepping motor drive for paper feed and optical systems in copier, and drum drive in laser beam printers pen drive in x-y plotters industrial robots and other stepping motor application products features the STK672-010 can easily implement stepping motor drive applications with the provision of a dc power supply and a clock pulse oscillator. <4-phase distribution controller> the STK672-010 supports four excitation types selected by the excitation mode setting (m1 and m2). 1. 4-phase 1 excitation 2. 4-phase 1-2 excitation 3. 4-phase 2 excitation 4. 4-phase w1-2 excitation schmitt input pins (for a high noise margin) controller inputs are cmos compatible (with built-in pull-up resistors), thus allowing direct control from i/o ports or special-purpose controller lsis. an interval is set up during mutual switching of the aa and bb phase output signals in 4-phase 2 excitation mode. since the STK672-010 is a separate excitation type circuit, it supports a wide operating power supply voltage range. (v cc 1 = 5 to 42 v) current detection resistors are provided within the hybrid ic. drive power reduced by 70% when compared to the stk6770 series (at 1 a drive). can provide a motor drive current of up to 1.7 a without a heat sink. package dimensions unit: mm 4149 [STK672-010] STK672-010 sanyo electric co.,ltd. semiconductor bussiness headquarters tokyo office tokyo bldg., 1-10, 1 chome, ueno, taito-ku, tokyo, 110-8534 japan unipolar fixed-current chopper (separate excitation) type 1.7 a output current stepping motor driver with built-in 4-phase distribution controller thick-film hybrid ic any and all sanyo 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? control systems, or other applications whose failure can be reasonably expected to result in serious physical and/or material damage. consult with your sanyo representative nearest you before using any sanyo products described or contained herein in such applications. sanyo assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all sanyo products described or contained herein.
specifications absolute maximum ratings at ta = 25 c allowable operating ranges at ta = 25 c electrical characteristics at ta = 25 c, v cc 1 = 36 v, v cc 2 = 5 v ac characteristics at ta = 25 c, v cc 1 = 36 v, v cc 2 = 5.0 v, c l = 50 pf note: use a rated power supply. definition of the delay time tpd no. 4927- 2 /17 STK672-010 parameter symbol conditions ratings unit maximum supply voltage v cc 1 max no signal 52 v v cc 2 max no signal 7.0 v maximum phase output current i oh max 0.5 s, 1 pulse 2.5 a repeat avalanche capacity ear max 38 mj input voltage v in max 7.0 v operating substrate temperature tc max 105 c junction temperature tj max 150 c storage temperature range tstg ?0 to +125 c parameter symbol conditions ratings unit operating supply voltage v cc 1 with a signal present 18 to 42 v v cc 2 with a signal present 5 5% v input voltage v ih 0 to v cc 2 v phase drive withstand voltage v dss 120 v phase current i oh max duty: 50% per phase 1.7 a parameter symbol conditions min typ max unit output saturation voltage vst r l = 23 1.1 1.5 v output current (average) ioave load (each phase): r = 3.5 , l = 3.8 mh 0.45 0.50 0.59 a fet diode forward voltage vdf if = 1.0 a 1.2 1.8 v current when stopped icco 36 55 ma on input voltage v ih pins 14, 15, 16, 17, 18, and 19 4.0 v off input voltage v il pins 14, 15, 16, 17, 18, and 19 1.0 v input leakage current i i pins 14, 15, 16, 17, 18, and 19 ?00 +30 a c1 to c3 high level voltage cv oh pins 1, 2, and 3 2.4 v c1 to c3 low level voltage cv ol pins 1, 2, and 3 0.4 v chopping frequency fc r/c: 2.4 k /6800 pf 35 42 50 khz parameter symbol conditions min typ max unit delay time tpd1 for the clock path: clk ? a, a, b, b 2 s tpd2 for the clock path: clk ? c1, c2, c3 2 s output signal interval tin only for 4-phase 2 excitation 20 40 s maximum clock frequency f clk 20 khz
definition of the output signal interval tin function table operating mode excitation mode equivalent circuit no. 4927- 3 /17 STK672-010 cw/ccw start/stop cw l l ccw h l stop 5 h m1 m2 4-phase 1 excitation l l 4-phase 2 excitation h l 4-phase 1-2 excitation l h 4-phase w1-2 excitation h h
sample application circuit (w1-2 phase excitation, motor current: four stage switching) note: 1. see the function tables and the timing chart for details on the i/o port signals. 2. use the sanyo lb1212, lb1214, or equivalent for the tr array. 3. the reset pin should normally be left open. no. 4927- 4 /17 STK672-010
STK672-010 operation fig. 1 STK672-010 driver block basic circuit figures 1 and 2 show the driver block basic circuit and the waveforms in the various blocks. unlike the earlier stk6710 series, which adopted mosfet transistors, the STK672-010 implements a fixed current drive scheme with separate excitation. fig. 2 waveform timing chart thus the chopping operation is partially fixed at the oscillator frequency by the latch function. the STK672-010 repeats the operation of switching the motor current on and off, i.e., fixed current chopping operation, as described above. no. 4927- 5 /17 STK672-010 when the fet is turned on by a high level input on the ? signal in the driver block basic circuit, the comparator + pin goes low and the comparator output goes low. the l1 current i on that flows in the fet at this time is given by the following formula. i on = (1 ? e t ) ..................... (1) l: coil inductance r: the sum of the coil resistance and rs then, when the rs voltage becomes equal to vref, the fet turns off. at this point the energy stored in the inductor l1 induces a current in l2 and the current i off flows. the time that the current i off flows is proportional to the off time set at the oscillator. r l v cc 1 ?vsat r
<4-phase distribution control logic block operation> fig. 3 control logic circuit the control logic ic built into the STK672-010 is a special-purpose ic developed to allow stepping motors to be operated more simply than was possible previously. features one of four excitation types can be selected with the excitation mode setting (m1 and m2). 1. 4-phase 1 excitation 2. 4-phase 1-2 excitation 3. 4-phase 2 excitation 4. 4-phase w1-2 excitation schmitt circuits are provided on all input pins (for a high noise margin). inputs have 10 k pull-up resistors built in so that they are cmos and ttl input compatible. thus the inputs can be driven directly from i/o ports or special-purpose lsis. the aa and bb phases of 4-phase control output at the 2-phase excitation set up the interval times. the minimum pulse width for the control logic is 25 s. the logic operates on pulse falling edges. the following timing charts show the logic in each excitation mode. no. 4927- 6 /17 STK672-010
fig. 4 4-phase 1 excitation timing chart fig. 5 4-phase w1-2 excitation timing chart no. 4927- 7 /17 STK672-010
fig. 6 4-phase 2 excitation timing chart fig. 7 4-phase 1-2 excitation timing chart no. 4927- 8 /17 STK672-010
fig. 8 motor output current waveform fig. 9: vref peripheral circuit the output current range is from 0.1 a of the current caused by the t off time in oscillator to 1.7 a of the allowable maximum current. the STK672-010 provides the control logic circuit to allow the current to be switched over up to four levels by the c1, c2, and c3. a low saturation transistor must be used on the vref voltage switching device in the w1-2 phase excitation circuit. the reason for this is that when the w1-2 phase excitation current is switched over up to four levels, for switching i o at small settings the i o waveform will be displaced from the desired value due to variations in the v ce (sat) voltage drop of the external vref switching device. this can result in increased motor vibrations. therefore we recommend selecting a device with a v ce (sat) of about 10 mv at i c = 100 a for this transistor at the operating conditions used for this circuit. note that although we proposed using the lb1212 or lb1214, this does not necessarily apply to designs that take mass production into consideration. the output current setting ratios for w1-2 phase excitation are 100%, 92%, 70%, and 38% for four-level switching and 100% and 70% for two-level switching. these are target values and precise adjustment should be made in the actual circuit. a description of the w1-2 phase excitation follows. no. 4927- 9 /17 STK672-010 |