MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER DESCRIPTION PIN CONFIGURATION (TOP VIEW) The M54640P is a semiconductor IC to drive a stepper motor by the bipolar method. FEATURES ● Bipolar and constant-current drive M54640P Output MB ← 1 One-shot-multi T→ 2 time constant Output power VMM 3 supply 4 ● Wide current control rage (20 – 800mA) GND 5 ● Wide supply voltage drive range (10 – 40V) Power supply VCC ● Built in flywheel diodes Output current value setting Output current direction switching ● Current level can be changed by steps or continuously. ● Built in a thermal shutdown circuit I1 16 → E Current sensor 15 → MA Output 14 power VMM Output supply 13 GND 12 6 11 ← VR 7 10 ← C Ph → 8 9 Io Comparator reference input Comparator input Output current setting Outline 16P4 APPLICATION Printer, FDD, HDD, Fax FUNCTION each comparator, and then each comparator output triggers The M54640P drives a stepper motor by the bipolar drive method to monomulti and the current is cut for a certain time (tOFF) by utilizing change the current direction of a single coil and controls the current the inductance of the coil. direction with PHASE input pin. In order to obtain higher efficiency, Also, diodes needed for choppering and a thermal shutdown circuit the constant current drive system to control the coil current is as a countermeasure against overvoltage are built in this circuit. introduced. The current value can be selected among four levels (0 to max.) by selecting the combination of three internal comparators by logic input. It also can be continuously changed by controlling the reference voltage. Conversion to voltage is conducted by the current value sensing resistor (Rs) and the voltage is sensed with BLOCK DIAGRAM Comparator reference input VCC VR 11 6 Output MA 15 1 Output MB Schmitt trigger Cutput current Ph 8 direction switcing Output current value setting 1 1 1 >1 >1 I1 7 I0 9 00 01 10 11 VKH VKM Monostable tOFF = 0.69 • RT CT VKL 4 GND Current sensor 5 12 13 10 2 16 C Comparator input T One-shot-multi time constant E Current sensor 3 VMM 14 Output power supply MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER ABSOLUTE MAXIMUM RATINGS (Ta=25°C, unless otherwise noted) Symbol VCC VMM VL VC VR IL IC IMM Pd Topr Tstg Parameter Conditions Supply voltage Output supply voltage Logic input voltage Analog input voltage Comparative input voltage Logic input current Analog input current Output supply current Power dissipation Operating temperature Storage temperature Mounted on a board Ratings Unit -0.3 – 7 -0.3 – 45 -0.3 – 6 -0.3 – VCC -0.3 – 15 -10 -10 ±1000 1.92 -20 – 75 -55 – 125 V V V V V mA mA mA W °C °C Note. Every voltage value is measured when the voltage at GND pin is 0V. The maximum and the minimum of each voltage value are shown in absolute values. Regarding current directions, inflow current is shown in a positive value and outflow current is shown in a negative value. The maximum and the minimum of each current value are shown in absolute values. RECOMMENDED OPERATING CONDITIONS (Ta=25°C, unless otherwise noted) Symbol VCC VMM IO tPLH tPHL TON Parameter Min. Supply voltage Output supply voltage Output current Logic input rise time Logic input fall time Thermal shutdown temperature 4.75 10 20 Limits Typ. 5 Max. 5.25 40 800 2 2 175 Unit V V mA µs µs °C ELECTRICAL CHARACTERISTICS (VCC=5V, Ta=25°C, unless otherwise noted) Symbol Parameter VIH VIL VCH VCM VCL ICO IOFF Comparator input current Output cutoff current Vsat Saturation voltage tOFF td ICC IIH IIL Cutoff time Turnoff delay Supply current Logic input voltage Test conditions “H” “L” VR=5V, I0=I1=0 VR=5V, I0=1,I1=0 VR=5V, I0=0, I1=1 Comparator threshold Logic input current VCC=5V Min. 2.0 0 400 240 75 -20 Limits Typ. 430 260 90 I0=I1=1(Ta=25°C) The voltage at the sensing resistor is not included. IO=500mA “H” “L” VMM=10V, tON≥5µs Ta=25°C, dVK/dt≥50mV/µs VCC=5V VI=2.4V VI=0.4V 25 30 1.6 Max. Unit VCC 0.8 450 280 100 20 100 mV 4.0 V 35 2.0 25 20 -0.4 µs µs V µA µA mA µA mA MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER SWITCHING CHARACTERISTICS Test circuit Switching waveforms VMA – VMB or VMB – VMA tOFF = 0.69RTCT 1 CT 1 MB E 16 1/2 MA 15 2 T VMM 14 3 VMM RT 4 tON tOFF RS CV VCC 13 GND GND 12 5 td RC VR 11 6 VCC C 10 7 I1 8 Phase I0 9 CC VCH VCM VCL RS :1Ω RC : 1kΩ RT : 56kΩ CC : 820pF CT : 820pF CV : 47µF APPLICATION DESCRIPTION • Current sensor When the voltage fall at the current sensing resistor and the selected current level becomes of the same level, the comparator • PHASE INPUT Phase input decides the output mode. triggers the monostable. Then, the output stage is cut off for a certain time (tOFF). During this cutoff time, the current volume PHASE MA H H L L L H MB decreases slightly and falls short of the comparison level. After the cutoff time (tOFF), the output stage is in ON state again. This operation is repeated. • Single pulse generator • I0, I1 I0 and I1 fixed based on the comparison voltage VR decide the output current level. The current level can be continuously changed by changing the voltage at VR continuously. At the comparator output rise edge, the monostable is triggered. The pulse width of the monostable at the external timing Rt and Ct is as follows. tOFF = 0.69 x RtCt Retrigger during tOFF is neglected. I0 I1 Current level H H 0 L H Low H L Average L L High • Analog control The output current level can be continuously changed by changing the voltage at VR or the feedback voltage to the comparator. MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER TIMING CHART 2-phase excitation Phase A Phase B I0, 1 = (A) = 0 I0, 1 = (B) = 0 1-2-phase excitation Phase A Phase B I0, 1 = (A) I0, 1 = (B) Microstep (divided into six) Phase A Phase B I0 (A) I1 (A) I0 (B) I1 (B) MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER TYPICAL CHARACTERISTICS (Absolute maximum ratings) Safety operating temperature 1.0 A : Recommended Output current Io (A) 0.8 B : Schottky diodes should be externally connected between output pins and power supply pins. B 0.6 C : Schottky diodes should be externally instaalled between output pins and power supply pins and between output pins and GND pin. 0.4 A C 0.2 0 0 10 20 30 40 45 50 Output VMM (V) Thermal derating 10.0 Allowable power dissipation (W) θj-c = 10°C/W A : Mounted on a 25cm2 glass epoxy board which is coated with copper on one side. θc-a = 45°C/W B : 10cm2 aluminum heat sink (1t) is used. θc-a = 25°C/W C : 100cm2 aluminum heat sink (1t) is used. θc-a = 10°C/W Tj(max) = 150°C 8.0 6.0 C 4.0 B A 2.0 0 0 25 50 Ambient (°C) 75 100 MITSUBISHI <CONTROL / DRIVER IC> M54640P STEPPER MOTOR DRIVER APPLICATION EXAMPLE 1Ω 820pF 1kΩ 16 15 14 13 12 5V 11 10 9 6 8 M54640P 1 2 3 4 5 7 820pF Phase A 56kΩ I0A I1A 1Ω 820pF 1kΩ 24V 47µF 16 15 14 13 12 11 10 9 Stepper motor M54640P 1 2 3 4 5 6 7 8 Phase B 820pF I0B I1B 56kΩ PRECAUTIONS FOR USE (3) Thermal shutdown function (1) When the whole output current changes by a large margin (for • The state of thermal shutdown operation may differ according to example, when overheat protection operation causes intermittent the way of wiring within a board. Therefore, sufficient board flow of output current), the supply voltage may undergo a evaluation should be conducted before use. When the board is change. Therefore, selection and wiring of power supply should changed, operation on the replacing board should be evaluated. be conducted cautiously to avoid such a situation that the supply • The circuit board on which this IC is mounted is designed to voltage exceeds the absolute maximum ratings. realize low impedance between power supply and output pin. (2) When the supply voltage changes by a large margin, the Therefore, it is desirable to take a safe measure such as fixing a operation of this IC may become unstable. In this case, the fuse to avoid such a situation that the board is damaged by a fire change of supply voltage can be controlled by connecting a when output pin is internally short-circuited by excessively capacitor at the point near to IC pin between Vcc pin and GND applied surge voltage by accident. pin. (See above application example.)