LV8740V Bi-CMOS LSI PWM Current Control Stepper Motor Driver Application Note http://onsemi.com Overview The LV8740V is a 2-channel H-bridge driver IC that can switch a stepper motor driver, which is capable of micro-step drive and supports Full-step, Half-step (full torque), Half-step, and Quarter-step resolution, and two channels of a brushed motor driver, which supports forward, reverse, brake, and standby of a motor. Function Single-channel PWM current control stepper motor driver (selectable with DC motor driver channel 2) incorporated. BiCDMOS process IC On resistance (upper side: 0.3Ω; lower side: 0.2Ω; total of upper and lower: 0.5Ω; Ta = 25C, IO = 2.5A) Micro step mode can be set to Full-step, Half-step (full torque), Half-step, or Quarter-step mode Excitation step proceeds only by step signal input Motor current selectable in four steps Output short-circuit protection circuit (selectable from latch-type or auto reset-type) incorporated Unusual condition warning output pins Built-in thermal shutdown circuit No control power supply required Typical Applications MFP (Multi Function Printer) PPC (Plain Paper Copier) LBP (Laser Beam Printer) Scanner Industrial Cash Machine Amusement Textile Semiconductor Components Industries, LLC, 2013 December, 2013 1/41 LV8740V Application Note Package Dimensions unit : mm (typ) TOP VIEW SIDE VIEW BOTTOM VIEW 15.0 44 0.5 (3.6) 7.6 5.6 (7.8) 1 2 0.65 0.2 0.22 1.7 MAX (0.68) 0.1 (1.5) SIDE VIEW SANYO : SSOP44J(275mil) Caution: The package dimension is a reference value, which is not a guaranteed value. Recommended Soldering Footprint (Unit: mm) Reference symbol SSOP44J(275mil) eE 7.00 e 0.65 b3 0.32 l1 1.00 X (7.8) Y (3.5) 2/41 LV8740V Application Note Pin Assignment VG 1 44 OUT1A VM 2 43 OUT1A CP2 3 42 PGND1 CP1 4 41 NC VREG5 5 40 NC ATT2 6 39 VM1 ATT1 7 38 VM1 EMO 8 37 RF1 CEM 9 36 RF1 EMM 10 35 OUT1B RCHOP 11 MONI 12 LV8740V RST 13 34 OUT1B 33 OUT2A 32 OUT2A STP/DC22 14 31 RF2 FR/DC21 15 30 RF2 MD2/DC12 16 29 VM2 MD1/DC11 17 28 VM2 DM 18 27 NC OE 19 26 NC ST 20 25 PGND2 VREF 21 24 OUT2B GND 22 23 OUT2B Top view It is short-circuited in IC though there are VM1, VM2, OUT1A, OUT1B, OUT2A, OUT2B, RF1 and RF2 of each of two pins. 3/41 LV8740V Application Note Block Diagram CP2 CP1 VG OUT1A RF1 OUT1B VM1 VM2 OUT2A OUT2B RF2 VREG5 Output preamplifier stage MONI Output preamplifier stage Output preamplifier stage Charge pump PGND Output preamplifier stage VM EMO Output control logic Regulator CEM VREF Attenuator (4 levels selectable) Current selection (full/half-full/ half/quarter) Current selection (full/half-full/ half/quarter) Oscillation circuit TSD LVS RCHOP ST ATT1 ATT2 MD1/ MD2/ FR/ DC11 DC12 DC21 STP/ RST DC22 OE DM EMM CPU Mi-com GND 4/41 LV8740V Application Note Specifications Absolute Maximum Ratings at Ta = 25C Parameter Symbol Conditions Supply voltage 1 VM max Output peak current IO peak tw 10ms, duty 20%, Each 1ch Output current IO max Each 1ch Logic input voltage Ratings VIN MONI/EMO input voltage Allowable power dissipation Operating temperature VMONI/VEMO Pd max * Topr Storage temperature Tstg * Specified circuit board : 90901.6mm3 : 2-Layer glass epoxy printed circuit board with back mounting. Unit 38 V 3.0 A 2.5 A -0.3 to +6.0 V -0.3 to +6.0 V 3.45 W -30 to +85 C -55 to +150 C Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time. Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current, high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details. Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Recommended Operating Conditions at Ta 25C Parameter Supply voltage range Logic input voltage VREF input voltage range Symbol Conditions Ratings min typ Unit max VM VIN 9 35 V 0 5.5 V VREF 0 3.0 V Electrical Characteristics at Ta = 25°C, VM = 24V, VREF = 1.5V Parameter Standby mode current drain 1 Current drain Symbol IMstn IM VREG5 output voltage Thermal shutdown temperature Thermal hysteresis width Vreg5 Conditions Ratings min typ ST = ”L” ST = ”H”, OE = ”L”, no load Unit max 180 250 A 3 5 mA IO=-1mA 4.7 5.0 5.3 V TSD Design guarantee 150 180 210 C TSD Design guarantee 40 Ronu IO = 2.5A, Upper-side on resistance IO = 2.5A, Lower-side on resistance 0.3 0.4 Ω 0.2 0.25 Ω 50 A 1.1 1.3 V 3 8 15 A 48 80 112 A 3 8 15 A 30 50 70 A 0.8 V C Motor Driver Output on-resistance Rond Output leakage current IOleak Diode forward voltage VD ID = -2.5A ISTL VIN = 0.8V VIN = 5V ST pin input current ISTH Logic pin input current IINL (other ST pin) IINH VINH VINL Logic high-level input voltage Logic low-level input voltage Current Quarter-step selection drive Vtdac0_W VIN = 0.8V VIN = 5V 2.0 Step 0(When initialized : channel 1 V 0.290 0.300 0.310 V comparator level) comparator Vtdac1_W Step 1 (Initial state+1) 0.260 0.270 0.280 V threshold Vtdac2_W Step 2 (Initial state+2) 0.200 0.210 0.220 V voltage Vtdac3_W Step 3 (Initial state+3) 0.095 0.105 0.115 V Vtdac0_H Step 0 (When initialized: channel 1 0.290 0.300 0.310 V Vtdac2_H Step 2 (Initial state+1) 0.200 0.210 0.220 V Step 0 (Initial state, channel 1 comparator 0.290 0.300 0.310 V (Current step Half-step drive switch) comparator level) Half-step (full Vtdac0_HF torque) drive level) Vtdac2_HF Full-step drive Vtdac2_F Step 2 (Initial state+1) 0.290 0.300 0.310 V Step 2 0.290 0.300 0.310 V Current selection comparator Vtatt00 ATT1=L, ATT2=L 0.290 0.300 0.310 V threshold voltage Vtatt01 ATT1=H, ATT2=L 0.190 0.200 0.210 V (Current attenuation rate switch) Vtatt10 ATT1=L, ATT2=H 0.140 0.150 0.160 V Vtatt11 ATT1=H, ATT2=H 0.090 0.100 0.110 V Continued on next page. 5/41 LV8740V Application Note Continued from preceding page. Parameter Chopping frequency VREF pin input current MONI pin saturation voltage Symbol Fchop Conditions RCHOP = 20kΩ Iref VREF = 1.5V Vsatmon IMONI=1mA Ratings min typ 45 Unit max 62.5 75 kHz 50 100 mV 28 28.7 29.8 V 0.5 ms 90 125 150 kHz 50 100 mV A -0.5 Charge pump VG output voltage VG Rise time tONG VG = 0.1F Oscillator frequency Fosc RCHOP = 20kΩ Output short-circuit protection EMO pin saturation voltage CEM pin charge current CEM pin threshold voltage Vsatemo Icem Vtcem Iemo = 1mA Vcem=0V 7 10 13 A 0.8 1.0 1.2 V 6/41 LV8740V Application Note 7/41 LV8740V Application Note 8/41 LV8740V Application Note Pin Functions Pin No. Pin Name Pin Function 6 ATT2 Motor holding current switching pin. 7 ATT1 Motor holding current switching pin. 10 EMM Output short-circuit protection mode 13 RST RESET signal input pin 14 STP/DC22 STEP signal input pin (STM) / Channel 2 15 FR/DC21 Equivalent Circuit VREG5 switching pin. output control input pin 2 (DCM). CW / CCW signal input pin (STM) / Channel 2 output control input pin 1 (DCM). 16 MD2/DC12 Excitation mode switching pin 2 (STM) / Channel 1 output control input pin 2 (DCM). 17 MD1/DC11 Excitation mode switching pin 1 (STM) / Channel 1 output control input pin 1 (DCM). 18 DM Drive mode (STM/DCM) switching pin. 19 OE Output enable signal input pin. 20 ST Chip enable pin. GND VREG5 GND 23, 24 OUT2B Channel 2 OUTB output pin. 25, 42 PGND Power system ground. 28, 29 VM2 Channel 2 motor power supply 30, 31 RF2 32, 33 OUT2A Channel 2 OUTA output pin. 34, 35 OUT1B Channel 1 OUTB output pin. 36, 37 RF1 Channel 1 current-sense resistor 38, 39 VM1 Channel 1 motor power supply pin. 43, 44 OUT1A Channel 1 OUTA output pin. 38 39 28 29 connection pin. Channel 2 current-sense resistor connection pin. 43 44 34 35 32 33 23 24 connection pin. 25 42 36 37 30 31 GND Continued on next page. 9/41 LV8740V Application Note Continued from preceding page. Pin No. Pin Name Pin Function 1 VG Charge pump capacitor connection pin. 2 VM Motor power supply connection pin. 3 CP2 Charge pump capacitor connection pin. 4 CP1 Charge pump capacitor connection pin. Equivalent Circuit 4 VREG5 2 3 1 GND 21 VREF Constant current control reference voltage input pin. VREG5 GND 5 VREG5 Internal power supply capacitor connection pin. VM GND 8 EMO Output short-circuit state warning output pin. 12 MONI VREG5 Position detection monitor pin. GND Continued on next page. 10/41 LV8740V Application Note Continued from preceding page. Pin No. 9 Pin Name CEM Pin Function Pin to connect the output short-circuit state detection time setting capacitor. Equivalent Circuit VREG5 GND 11 RCHOP Chopping frequency setting capacitor connection pin. VREG5 GND 22 26, 27 40, 41 GND NC Ground. No Connection (No internal connection to the IC) . 11/41 LV8740V Application Note Description of operation Input Pin Function The function to prevent including the turn from the input to the power supply is built into each input pin. Therefore, the current turns to the power supply even if power supply (VM) is turned off with the voltage impressed to the input pin and there is not crowding. (1) Chip enable function This IC is switched between standby and operating mode by setting the ST pin. In standby mode, the IC is set to power-save mode and all logic is reset. In addition, the internal regulator circuit and charge pump circuit do not operate in standby mode. ST Mode Internal regulator Low or Open Standby mode Standby Charge pump Standby High Operating mode Operating Operating (2) Drive mode switching pin function The IC drive mode is switched by setting the DM pin. In STM mode, stepping motor channel 1 can be controlled by the CLK-IN input. In DCM mode, DC motor channel 2 or stepping motor channel 1 can be controlled by parallel input. Stepping motor control using parallel input is full-step or half-step full torque. DM Drive mode Application Low or Open STM mode Stepping motor channel 1 (CLK-IN) High DCM mode DC motor channel 2 or stepping motor channel 1 (parallel) STM mode (DM = Low or Open) (1) STP pin function The excitation step progresses by inputting the step signal to the STP pin. Input Operating mode ST STP Low * Standby mode High Excitation step proceeds High Excitation step is kept STP input MIN pulse width (common in H/L): 500ns (MAX input frequency: 1MHz) However, constant current control is performed by PWM during chopping period, which is set by the resistor connected between RCHOP and GND. You need to perform chopping more than once per step. For this reason, for the actual STP frequency, you need to take chopping frequency and chopping count into consideration. For example, if chopping frequency is 62.5kHz (16µs) and chopping is performed twice per step, the maximum STP frequency is obtained as follows: f=1/(16µs × 2) = 31kHz. (2) Input timing TstepH/TstepL : Clock H/L pulse width (min 500ns) Tds : Data set-up time (min 500ns) Tdh : Data hold time (min 500ns) 12/41 LV8740V Application Note (3) Positional detection monitor function Positional detection monitor MONI pin is an open drain output. When the excitation position is an initial position, the MONI output becomes ON. Please refer to (example of current wave type in each excitation mode). (4) Setting constant-current control reference current This IC is designed to automatically exercise PWM constant-current chopping control for the motor current by setting the output current. Based on the voltage input to the VREF pin and the resistance connected between RF and GND, the output current that is subject to the constant-current control is set using the calculation formula below: IOUT = (VREF/5)/RF resistance * The above setting is the output current at 100% of each microstep mode. If VREF is open or the setting is out of the recommendation operating range, VREF is set around 5V. As a result, output current will increase and you cannot set constant current under normal condition. Hence, make sure that VREF is set in accordance with the specification. However, if current control is not performed (if the IC is used without saturation drive or current limit) make sure that the setting is as follows: VREF=5V or VREF=VREG5 The voltage input to the VREF pin can be switched to four-step settings depending on the statuses of the two inputs, ATT1 and ATT2. This is effective for reducing power consumption when motor holding current is supplied. Attenuation function for VREF input voltage ATT1 ATT2 Current setting reference voltage attenuation ratio Low Low 100% High Low 66.7% Low High 50% High High 33.3% 50ms/div ATT1 5V/div ATT2 5V/div VM=24V VREF=1V RF=0.22Ω Motor Current Iout1 0.5A/div Iout2 0.5A/div 100% 50% The formula used to calculate the output current when using the function for attenuating the VREF input voltage is given below. IOUT = (VREF/5) × (attenuation ratio)/RF resistance Example : At VREF of 1.65V, a reference voltage setting of 100% [(ATT1, ATT2) = (L, L)] and an RF resistance of 0.22Ω, the output current is set as shown below. IOUT = 1.65V/5 × 100%/0.22Ω = 1.5A If, in this state, (ATT1, ATT2) is set to (H, H), IOUT will be as follows : IOUT = 1.5A × 33.3% = 0.5A In this way, the output current is attenuated when the motor holding current is supplied so that power can be conserved. 13/41 LV8740V Application Note (5) Reset function RST Operating mode Low Normal operation High Reset state When the RST pin is set to High, the excitation position of the output is forcibly set to the initial state, and the MONI output is placed in the ON state. When RST is then set to Low, the excitation position is advanced by the next STEP input. (6) Output enable function OE Operating mode High Output OFF Low Output ON When the OE pin is set High, the output is forced OFF and goes to high impedance. However, the internal logic circuits are operating, so the excitation position proceeds when the STEP signal is input to the STP pin. Therefore, when OE is returned to Low, the output level conforms to the excitation position proceeded by the STEP input. 14/41 LV8740V Application Note (7) Forward/reverse switching function FR Operating mode Low Clockwise (CW) High Counter-clockwise (CCW) The internal D/A converter proceeds by one bit at the rising edge of the input STEP pulse. In addition, CW and CCW mode are switched by setting the FR pin. In CW mode, the channel 2 current phase is delayed by 90° relative to the channel 1 current. In CCW mode, the channel 2 current phase is advanced by 90° relative to the channel 1 current. (8) Setting the chopping frequency For constant-current control, chopping operation is made with the frequency determined by the external resistor (connected to the RCHOP pin). The chopping frequency to be set with the resistance connected to the RCHOP pin (pin 11) is as shown below. Chopping frequency settings (reference data) 100 Fchop – kHz 80 60 40 20 0 0 10 20 30 RCHOP – kΩ 40 50 60 PCA01883 15/41 LV8740V Application Note (9) Blanking period If, when exercising PWM constant-current chopping control over the motor current, the mode is switched from decay to charge, the recovery current of the parasitic diode may flow to the current sensing resistance, causing noise to be carried on the current sensing resistance pin, and this may result in erroneous detection. To prevent this erroneous detection, a blanking period is provided to prevent the noise occurring during mode switching from being received. During this period, the mode is not switched from charge to decay even if noise is carried on the current sensing resistance pin. In this IC, the blanking time is fixed at 1/16 of one chopping cycle. (10) Output current vector locus (one step is normalized to 90 degrees) 100 θ2'(Full-step / Half-step full torque) θ0 θ1 Channel 1 phase current ratio (%) 80 θ2 60 40 θ3 20 θ4 0 0 20 40 60 Channel 2 phase current ratio (%) 80 100 Setting current ration in each microstep resolution STEP Quarter Step (%) Channel 1 Half Step (%) Channel 2 Channel 1 0 100 0 1 90 35 2 70 70 3 35 90 4 0 100 Half Step (full torque) (%) Channel 2 Channel 1 Full Step (%) Channel 2 Channel 1 100 0 100 0 70 70 100 100 0 100 0 100 100 Channel 2 100 16/41 LV8740V Application Note (11) Excitation mode setting function The excitation mode of the stepping motor can be set as follows by setting the MD1 pin and the MD2 pin. MD1 MD2 Microstep Resolution Excitation mode Initial position Channel 1 Channel 2 Low Low Full Step 2 phase 100% -100% High Low Half Step (full torque) 1-2 phase (full torque) 100% 0% Low High Half Step 1-2 phase 100% 0% High High Quarter Step W1-2 phase 100% 0% This is the initial position of each excitation mode in the initial state after power-on and when the counter is reset. (12) Excitation mode switching operation When excitation mode is switched while the motor is rotating, each drive mode operates with the following sequence. Clockwise mode Before the Microstep Resolution changes Microstep mode Quarter Step Position Position after the Microstep Resolution is changed Quarter Step Half Step (full torque) Full Step θ0 θ2 θ2' θ2' θ1 θ2 θ2' θ2' θ2 θ4 θ4 θ2' θ3 θ2 θ2' θ2' -θ2 -θ2' -θ2' θ2' θ2' θ4 θ0 Half Step Half Step θ1 θ2 θ3 θ2' θ2' θ4 -θ3 -θ2' -θ2' θ0 θ1 θ2' θ2' Half Step (full torque) θ2' θ3 θ4 θ2' θ4 -θ3 -θ2 Full Step θ2' θ3 θ4 -θ2' θ4 *As for 0 to 4, please refer to the step position of current ratio setting. If you switch microstep mode while the motor is driving, the mode setting will be reflected from the next STEP and the motor advances to the closest excitation position at switching operation. 17/41 LV8740V Application Note (13) Typical current waveform in each Microstep mode Full Step (CW mode) STP MONI （％） I1 100 0 （％）－100 100 I2 0 －100 Half Step (full torque) (CW mode) STP MONI (%) 100 I1 0 －100 (%) 100 I2 0 －100 18/41 LV8740V Application Note Half step (CW mode) STP MONI (%) 100 I1 0 －100 (%) 100 I2 0 －100 Quarter Step (CW mode) STP MONI (%) 100 I1 0 －100 (%) 100 I2 0 －100 19/41 LV8740V Application Note (14) Current control operation specification (Sine wave increasing direction) (Sine wave decreasing direction) In each current mode, the operation sequence is as described below : At rise of chopping frequency, the CHARGE mode begins.(The section in which the CHARGE mode is forced regardless of the magnitude of the coil current (ICOIL) and set current (IREF) exists for 1/16 of one chopping cycle.) The coil current (ICOIL) and set current (IREF) are compared in this forced CHARGE section. When (ICOIL<IREF) state exists in the forced CHARGE section ; CHARGE mode up to ICOIL IREF, then followed by changeover to the SLOW DECAY mode, and finally by the FAST DECAY mode for the 1/16 portion of one chopping cycle. When (ICOIL<IREF) state does not exist in the forced CHARGE section; The FAST DECAY mode begins. The coil current is attenuated in the FAST DECAY mode till one cycle of chopping is over. Above operations are repeated. Normally, the SLOW (+FAST) DECAY mode continues in the sine wave increasing direction, then entering the FAST DECAY mode till the current is attenuated to the set level and followed by the SLOW DECAY mode. 20/41 LV8740V Application Note (15)Output transistor operation mode Charge increases current. Switch from Charge to Slow Decay Current regeneration by Slow Decay 4. 5. FAST 6. VM VM VM OFF OFF U1 OFF U2 ON ON L2 RF U2 OUTB OUTA OFF L1 L2 OFF OFF L1 RF Switch from Slow Decay to Fast Decay OFF U1 OUTB OUTA OFF L1 OFF U2 U1 OUTB OUTA ON L2 RF Switch from Fast Decay to Charge Current regeneration by Fast Decay This IC controls constant current by performing chopping to output transistor. As shown above, by repeating the process from 1 to 6, setting current is maintained. Chopping consists of 3 modes: Charge/ Slow decay/ Fast decay. In this IC, for switching mode (No.2, 4, 6), there are between the transistors. This off period is set to be constant (≈ 0.5µs) which is controlled by the internal logic. The diagrams show parasitic diode generated due to structure of MOS transistor. When the transistor is off, output current is regenerated through this parasitic diode. Output Transistor Operation Function OUTA→OUTB(CHARGE) Output Tr U1 U2 L1 L2 OUTB→OUTA(CHARGE) Output Tr U1 U2 L1 L2 CHARGE ON OFF OFF ON SLOW OFF OFF ON ON FAST OFF ON ON OFF CHARGE OFF ON ON OFF SLOW OFF OFF ON ON FAST ON OFF OFF ON 21/41 LV8740V Application Note 10ms/div STEP 5V/div VM=24V VREF=1V RF=0.22Ω RCHOP=20kΩ Motor Current 0.5A/div 20µs/div 20µs/div STEP 5V/div Set Current STEP 5V/div Set Current Motor Current 0.5A/div Motor Current 0.5A/div OUTA 20V/div OUTA 20V/div OUTB 20V/div OUTB 20V/div Sine wave increasing direction Sine wave decreasing direction Current mode 5µs/div Motor Current 200mA/div OUTA 20V/div FAST CHARGE OUTB 20V/div SLOW When the motor current reaches to the setting current, it is switched to Slow Decay mode. Motor current switches from Slow Decay mode to Fast Decay mode for 1/16 of one chopping cycle. 22/41 LV8740V Application Note DCM Mode (DM-High) (1) DCM mode output control logic Parallel input Output DC11 (21) DC12 (22) Low High Mode OUT1 (2) A OUT1 (2) B Low OFF OFF Standby Low High Low CW (Forward) Low High Low High CCW (Reverse) High High Low Low Brake When the control input switched from CW mode or CCW mode to standby mode, the current is pulled out with FAST DECAY. Afterwards, when the current becomes 0, the output is forcibly turned off. This forced OFF is released on the following condition. 1) Switched to CW mode or CCW mode. 2) Setting ST to low. Therefore, forced OFF might not be released, If the input signal is followed in order by CW (CCW) mode, standby mode, and brake mode. When the standby mode enters the above-mentioned timing, set the input time of the standby mode less than 0.5µs. (2) Reset function RST Operating mode MONI High or Low Reset operation not performed High output The reset function does not operate in DCM mode. In addition, the MONI output is High, regardless of the RST pin state. (3) Output enable function OE Operating mode High Output OFF Low Output ON When the OE pin is set High, the output is forced OFF and goes to high impedance. When the OE pin is set Low, output conforms to the control logic. 23/41 LV8740V Application Note (4)PWM control You can perform H-Bridge direct PWM control to DC11, DC12, DC21, and DC22 by inputting PWM signal. The maximum frequency of PWM signal is 200kHz. However, dead zone is generated when On-Duty is around 0%. Make sure to select optimum PWM frequency according to the target control range. Input-Output Characteristics of H-Bridge(Reference data) VM=24V,VREF=1.5V Forward/Reverse↔Brake 24/41 LV8740V Application Note Forward↔Brake No load , VM=24V , DC12=10kHz(DC11=H) 20µs/div High High Low High DC11 5V/div DC12 5V/div OUTA 10V/div OUTB 10V/div Forward Brake Forward↔Standby No load VM=24V , DC11=10kHz(DC12=L) 20µs/div High Low Low Low DC11 5V/div DC12 5V/div OUTA 10V/div OUTB 10V/div Forward Standby Motor load VM=24V , DC11=10kHz(DC12=L) 0.5µs/div 20µs/div Forward w/out load (no currnet), even if the counterpart transistor is on, output turns off at a MIN time (≈0.5µs) Standby Current=0A DC11 5V/div Motor Current 200mA/div OUTA 10V/div OUTB 10V/div Counterpart transistor ON Counterpart transistor ON Standby mode turns on the counterpart transistor (synchronous rectification) . After motor current fades off, output turns off. Synchronous rectification reduces heat generation compared to diode regeneration. 25/41 LV8740V Application Note (5) Current limit reference voltage setting function By setting a current limit, this IC automatically exercises short braking control to ensure that when the motor current has reached this limit, the current will not exceed it. (Current limit control time chart) Set current Current mode Coil current Forced CHARGE section fchop Current mode CHARGE SLOW 500µs/div VM=24V VREF=1V RF=0.22Ω ATT1=ATT2=L High DC11 5V/div Low DC12 5V/div Brush noise Current limit Motor Current 0.5A/div Forward Brake The limit current is set as calculated on the basis of the voltage input to the VREF pin and the resistance between the RF pin and GND using the formula given below. Ilimit = (VREF/5) /RF resistance The voltage applied to the VREF pin can be switched to any of the four setting levels depending on the statuses of the two inputs, ATT1 and ATT2. Function for attenuating VREF input voltage ATT1 ATT2 Low Low Current setting reference voltage attenuation ratio 100% High Low 66.7% Low High 50% High High 33.3% The formula used to calculate the output current when using the function for attenuating the VREF input voltage is given below. Ilimit = (VREF/5) × (attenuation ratio) /RF resistance Example : At VREF of 1.65V, a reference voltage setting of 100% [(ATT1, ATT2) = (L, L)] and an RF resistance of 0.22Ω, the output current is set as shown below. Ilimit = 1.65V/5 × 100%/0.22Ω = 1.5A If, in this state, (ATT1, ATT2) has been set to (H, H), Ilimit will be as follows : Ilimit = 1.5A × 33.3% = 0.5A 26/41 LV8740V Application Note (6) Blanking period In this IC, the blanking time is fixed at 1/8 of one chopping cycle. 5us/div Iout 100mA/div 16µs 2µs VOUT 10V/div 27/41 LV8740V Application Note (7) Typical current waveform in each excitation mode when stepping motor parallel input control Full Step (CW mode) DC11 DC12 DC21 DC22 （％） 100 I1 0 （％）－100 100 I2 0 －100 Half Step (full torque) (CW mode) DC11 DC12 DC21 DC22 (%) 100 I1 0 －100 (%) 100 I2 0 －100 28/41 LV8740V Application Note Output short-circuit protection function This output short protection circuit that makes the output a standby mode to prevent the thing that IC destroys when the output is short-circuited by a voltage short and the earth fault, etc. , and turns on the warning output to IC is built into. 1.High current flows if Tr1 and Tr4 are ON. 2.If RF voltage> setting voltage, then the mode switches to SLOW decay. 3.If the voltage between D and S of Tr4 exceeds the reference voltage for 4μs, short status is detected. VM short VM VM Tr1 Tr1 Tr3 ON OUTA OFF OUTA OFF OUTB M Tr2 OFF Tr3 Tr4 Tr2 ON ON OFF OUTB M Tr4 ON RF RF Short-circuit Detection (left schematic) 1.High current flows if Tr1 and Tr4 are ON 2. If the voltage between D and S of Tr1 exceeds the reference voltage for 4μs, short status is detected. GND short Short-circuit Detection VM Tr1 ON OUTA Tr3 M Tr2 OFF RF Load short Short-circuit Detection OFF OUTB VM Tr1 ON OUTA Tr4 Tr2 ON OFF Tr3 M OFF OUTB Tr4 ON RF (right schematic) 1.Without going through RF resistor, current control does not operate and current will continue to increase in CHARGE mode. 2. If the voltage between D and S of Tr1 exceeds the reference voltage for 4μs, short status is detected. 1.Without L load, high current flows. 2. If RF voltage> setting voltage, then the mode switches to SLOW decay. 3.During load short status in SLOW decay mode, current does not flow and overcurrent state is not detected. Then the mode is switched to FAST decay according to chopping cycle. 4. Since FAST state is short (≈1μs), switches to CHARGE mode before short is detected. 5.If voltage between D and S exceeds the reference voltage continuously during blanking time at the start of CHARGE mode (Tr1), CHARGE state is fixed (even if RF voltage exceeds the setting voltage, the mode is not switched to SLOW decay). After 4µs or so, short is detected. 29/41 LV8740V Application Note (1) Detect current (2) Output short-circuit protection operation changeover function Changeover to the output short-circuit protection of IC is made by the setting of EMM pin. EMM State Low or Open Latch method High Auto reset method (3) Latch method In the latch mode, the output is turned off when the output current exceeds the detection current, and the state is maintained. The output short protection circuit starts operating so that IC may detect a short output. When the short-circuit is the consecutive between internal timers (≈4µs), the output where the short-circuit is first detected is turned off. Even if the following time (Tcem) of the timer latch is exceeded, the output is turned ON again, and afterwards, when the short-circuit is detected, all the outputs of correspondence ch side are still switched to the standby mode, and the state is maintained. This state is released by making it to ST ="L". Output ON H-bridge output status Output ON Output OFF Standby state Threshold voltage 4µs CEM Voltage Short-circuit Detection state ShortRelease circuit Short-circuit Internal counter 1st counter 1st counter 1st counter start stop start 1st counter end 2nd counter start 2nd counter end 30/41 LV8740V Application Note (4) Automatic return method In the automatic return mode, the output wave type changes into the switching wave type when the output current exceeds the detection current. The short-circuit detection circuit operates when a short output is detected as well as the latch method. The output is switched to the standby mode when the operation of the short-circuit detection circuit exceeds the following time (Tcem) of the timer latch, and it returns to the turning on mode again after 2ms (TYP). At this time, the above-mentioned switching mode is repeated when is still in the overcurrent mode until the overcurrent mode is made clear. (5) Abnormal state warning output pin When IC operates the protection circuit detecting abnormality, the EMO pin has been installed as a terminal that outputs this abnormality to CPU side. This pin is an open drain output, and if abnormality is detected, the EMO output becomes (EMO="L") of ON. EMO pin enters on a state in the following. When a voltage short, the earth fault or the load is short-circuited and the output short-circuit protection circuit operates, the output pin When the junction temperature of IC rises, and the overheating protection circuit operates Unusual condition Channel 1 short-circuit detected EMO Channel 1 Output Channel 2 Output ON OFF - Channel 2 short-circuit detected ON - OFF Overheating condition detected ON OFF OFF (6) Timer latch time (Tcem) The time to output OFF when an output short-circuit occurs can be set by the capacitor connected between the CEM pin and GND. The capacitor (Ccem) value can be determined as follows: Tcem C V/I [sec] V : Threshold voltage of comparator TYP 1V I : CEM charge current TYP 10µA Timer latch: Tcem Latch type Auto reset type 1ms/div 5us/div OUT 10V/div OUT-GND short 1V st 1 counter 4µs nd 2 counter CEM 0.5V/div 2ms CEM charge EMO 5V/div 31/41 LV8740V Application Note Thermal shutdown function The thermal shutdown circuit is incorporated and the output is turned off when junction temperature Tj exceeds 180C and the abnormal state warning output is turned on. As the temperature falls by hysteresis, the output turned on again (automatic restoration). The thermal shutdown circuit does not guarantee the protection of the final product because it operates when the temperature exceed the junction temperature of Tjmax=150C. TSD = 180C (typ) TSD = 40C (typ) Charge Pump Circuit When the ST pin is set High, the charge pump circuit operates and the VG pin voltage is boosted from the VM voltage to the VM + VREG5 voltage. I will recommend the drive of the motor to put the time of tONG or more after the ST pin is made "H", and to begin because I cannot control the output if there is no pressure voltage of the voltage of the VG pin enough. ST VG pin voltage VM+VREG5 VM+4V VM tONG VG Pin Voltage Schematic View tONG Startup time with different VG capacitor 50µs/div ST 5V/div VM+4V 500µs/div VG 5V/div Vout 10V/div tONG VM=24V CP1-CP2=0.1µF VG=0.1µF 0.1µF/220µs 0.22µF/500µs 1µF/2.4ms VM=24V CP1-CP2=0.1µF VG=0.1µF/0.22µF/1µF 32/41 LV8740V Application Note Application Circuits Stepping motor driver application circuit example (DM=”L”) 0.1µF 1 VG OUT1A 44 2 VM OUT1A 43 3 CP2 PGND 42 4 CP1 NC 41 5 VREG5 NC 40 6 ATT2 VM1 39 7 ATT1 VM1 38 8 EMO RF1 37 9 CEM RF1 36 10 EMM OUT1B 35 0.1µF 0.1µF 24V Short-circuit state detection monitor 47kΩ 100pF 20kΩ Position detection monitor Clock input Logic input 1.5V 11 RCHOP LV8740V 10µF 0.22Ω OUT1B 34 12 MONI OUT2A 33 13 RST OUT2A 32 14 STP/DC22 RF2 31 15 FR/DC21 RF2 30 16 MD2/DC12 VM2 29 17 MD1/DC11 VM2 28 18 DM NC 27 19 OE NC 26 20 ST PGND 25 21 VREF OUT2B 24 22 GND OUT2B 23 M 0.22Ω Each constant setting type in the example of the above-mentioned circuit is as follows. When setting current ratio = 100%, VREF = 1.5V, the following output current flows : IOUT = VREF/5/RF resistance = 1.5V/5 × 100%/0.22Ω=1.36A Chopping frequency setting. 62.5kHz (RCHOP=20kΩ) Time of timer latch when output is short-circuited Tcem = CcemV × tcem/Icem = 100pF × 1V/10µA = 10µs 33/41 LV8740V Application Note DC motor driver application circuit example 0.1µF 1 VG OUT1A 44 2 VM OUT1A 43 3 CP2 PGND 42 4 CP1 NC 41 5 VREG5 NC 40 0.1µF 0.1µF M 24V 47kΩ Short-circuit state detection monitor 6 ATT2 VM1 39 7 ATT1 VM1 38 8 EMO RF1 37 9 CEM RF1 36 10 EMM OUT1B 35 100pF 20kΩ 11 RCHOP 12 MONI LV8740V 13 RST Logic input 10µF 0.22Ω OUT1B 34 OUT2A 33 OUT2A 32 14 STP/DC22 RF2 31 15 FR/DC21 RF2 30 16 MD2/DC12 VM2 29 17 MD1/DC11 VM2 28 0.22Ω M 1.5V 18 DM NC 27 19 OE NC 26 20 ST PGND 25 21 VREF OUT2B 24 22 GND OUT2B 23 Each constant setting type in the example of the above-mentioned circuit is as follows. When setting current LIMIT = 100%, VREF = 1.5V, the following output current flows : Ilimit = VREF/5/RF resistance = 1.5V/5 × 100%/0.22Ω=1.36A Chopping frequency setting. 62.5kHz (RCHOP=20kΩ) Time of timer latch when output is short-circuited Tcem = Ccem × Vtcem/Icem = 100pF × 1V/10µA = 10µs 34/41 LV8740V Application Note DC motor driver parallel connection application circuit example By connecting OUT1A and OUT2A as well as OUT2A and OUT2B, you can double the current capability. However, you cannot use current limit function. (RF=GND) 0.1µF 1 VG OUT1A 44 2 VM OUT1A 43 3 CP2 PGND 42 4 CP1 NC 41 5 VREG5 NC 40 6 ATT2 VM1 39 7 ATT1 VM1 38 8 EMO RF1 37 9 CEM RF1 36 10 EMM OUT1B 35 0.1µF 0.1µF 24V 47kΩ Short-circuit state detection monitor 10µF 100pF 20kΩ 11 RCHOP 12 MONI LV8740V 13 RST Logic input OUT1B 34 M OUT2A 33 OUT2A 32 14 STP/DC22 RF2 31 15 FR/DC21 RF2 30 16 MD2/DC12 VM2 29 17 MD1/DC11 VM2 28 18 DM NC 27 19 OE NC 26 20 ST PGND 25 21 VREF OUT2B 24 22 GND OUT2B 23 Each constant setting type in the example of the above-mentioned circuit is as follows. Chopping frequency setting. 62.5kHz (RCHOP=20kΩ) Time of timer latch when output is short-circuited Tcem = Ccem ×Vtcem/Icem = 100pF×1V/10µA = 10µs 35/41 LV8740V Application Note Allowable power dissipation Substrate Specifications (Substrate recommended for operation of LV8740V) Size : 90mm × 90mm × 1.6mm Material : Glass epoxy Copper wiring density : L1 = 85% / L2 = 90% L1 : Copper wiring pattern diagram L2 : Copper wiring pattern diagram Cautions 1) The data for the case with the Exposed Die-Pad substrate mounted shows the values when 90% or more of the Exposed Die-Pad is wet. 2) For the set design, employ the derating design with sufficient margin. Stresses to be derated include the voltage, current, junction temperature, power loss, and mechanical stresses such as vibration, impact, and tension. Accordingly, the design must ensure these stresses to be as low or small as possible. The guideline for ordinary derating is shown below: (1)Maximum value 80% or less for the voltage rating (2)Maximum value 80% or less for the current rating (3)Maximum value 80% or less for the temperature rating 3) After the set design, be sure to verify the design with the actual product. Confirm the solder joint state and verify also the reliability of solder joint for the Exposed Die-Pad, etc. Any void or deterioration, if observed in the solder joint of these parts, causes deteriorated thermal conduction, possibly resulting in thermal destruction of IC. 36/41 LV8740V Application Note Evaluation board LV8740V (90.0mm90.0mm1.6mm, glass epoxy 2-layer board, with backside mounting) Bill of Materials for LV8740V Evaluation Board Designator Quantity C1 1 C2 1 C3 1 C4 1 C5 1 C6 1 R1 1 R2 1 R3 1 R4 1 R5 1 IC1 SW1-SW11 TP1-TP25 1 11 25 Description Capacitor for Charge pump Capacitor for Charge pump 5VREG stabilization Capacitor Capacitor to set CEM timer VREF stabilization Capacitor VM Bypass Capasitor Pull-up Resistor for for terminal EMO Pull-up Resistor for for terminal MONI Resistor to set chopping frequency Channel 1 output current detective Resistor Channel 2 output current detective Resistor Motor Driver Switch Test Point Value Tolerance 0.1µF, 100V Substitution Allowed Lead Free Manufacturer Manufacturer Part Number ±10% Murata GRM188R72A104KA35* Yes Yes 0.1µF, 100V ±10% Murata GRM188R72A104KA35* Yes Yes 0.1µF, 100V ±10% Murata GRM188R72A104KA35* Yes Yes 100pF, 50V ±5% Murata GRM1882C1H101JA01* Yes Yes ±10% GRM188R72A104KA35* Yes Yes ±20% Murata SUN Electronic Industries 50ME10HC Yes Yes 47kΩ, 1/10W ±5% KOA RK73B1JT**473J Yes Yes 47kΩ, 1/10W ±5% KOA RK73B1JT**473J Yes Yes 20kΩ, 1/10W ±5% KOA RK73B1JT**203J Yes Yes 0.22Ω, 1W ±5% ROHM MCR100JZHJLR22 Yes Yes 0.22Ω, 1W ±5% ROHM SANYO ON semiconductors Semiconductor MIYAMA MAC8 MCR100JZHJLR22 Yes Yes LV8740V MS-621C-A01 ST-1-3 No Yes Yes Yes Yes Yes 0.1µF, 100V 10µF, 50V Footprint SSOP44J (275mil) 37/41 LV8740V Application Note Evaluation board circuit *VM Power supply input terminal 0.1µF 1 VG OUT1A 44 2 VM OUT1A 43 3 CP2 PGND 42 4 CP1 NC 41 5 VREG5 NC 40 (3) 6 ATT2 VM1 39 <4> 7 ATT1 VM1 38 C1 <2> 0.1µF C2 0.1µF C3 *VDD Power supply input terminal for Switch SW1 R1 R2 47kΩ 47kΩ SW2 100pF 10µF 8 EMO RF1 37 9 CEM RF1 36 10 EMM OUT1B 35 11 RCHOP OUT1B 34 0.22Ω R3 C4 SW3 20kΩ R3 12 MONI (2) SW4 (1) SW5 SW6 <1> SW7 SW8 SW9 *VREF Constant Current Control for Reference Voltage SW10 SW11 0.1µF Motor connection terminal C6 LV8740V 13 RST <3> OUT2A 33 OUT2A 32 14 STP/DC22 RF2 31 15 FR/DC21 RF2 30 16 MD2/DC12 VM2 29 17 MD1/DC11 VM2 28 18 DM NC 27 19 OE NC 26 20 ST PGND 25 21 VREF OUT2B 24 22 GND OUT2B 23 0.22Ω R4 (4) C5 【Stepping Motor】 VM=24V,VDD=3.3V,VREF=1.5V ST=H,DM=L EMM=L,RST=L,OE=L ATT1=ATT2=L, FR/DC21=L MD1/DC11=MD2/DC12=H STP/DC22=500Hz(Duty50%) 5ms/div 【DC Motor(OUT1A-OUT1B)】 VM=24V,VDD=3.3V,VREF=1.5V ST=H,DM=H EMM=L,RST=L,OE=L ATT1=ATT2=L, FR/DC21=STP/DC22=L MD1/DC11=H MD2/DC12=100kHz(Duty50%) (1) STEP 5V/div (2) MONI 5V/div (3) (4) Iout1 1A/div Iout2 1A/div 2µs/div <1> DC12 5V/div <2> OUT1A 10V/div <3> OUT1B 10V/div <4> Iout1 1A/div 38/41 LV8740V Application Note Evaluation Board Manual [Supply Voltage] VM (9 to 35V): Power Supply for LSI VREF (0 to 3V): Const. Current Control for Reference Voltage VDD (2 to 5V): Logic “High” voltage for toggle switch [Toggle Switch State] Upper Side: High (VDD) Middle: Open, enable to external logic input Lower Side: Low (GND) [Operation Guide] For stepping motor control 1. Initial Condition Setting: Set “Open” the toggle switch STP/D22, and “Open or Low” the other switches 2. Motor Connection: Connect the Motors between OUT1A and OUT1B, between OUT2A and OUT2B. 3. Power Supply: Supply DC voltage to VM, VREF and VDD. 4. Ready for Operation from Standby State: Turn “High” the ST terminal toggle switch. Channel 1 and 2 are into full-step initial position (100%, -100%). 5. Motor Operation: Input the clock signal into the terminal STP/DC22. 6. Other Setting (See Application Note for detail) i. ATT1, ATT2: Motor current attenuation. ii. EMM: Short circuit protection mode change. iii. RST: Initial Mode. iv. FR/DC21: Motor rotation direction (CW / CCW) setting. v. MD1/DC11, MD2/DC12: Excitation mode. vi. OE: Output Enable. For DC motor control 1. Initial Condition Setting: Set “Open” the toggle switch DM, and “Open or Low” the other switches 2. Motor Connection: Connect the Motor(s) between OUT1A and OUT1B, between OUT2A and OUT2B. 3. Power Supply: Supply DC voltage to VM, VREF and VDD. 4. Ready for Operation from Standby State: Turn “High” the ST and DM terminal toggle switch. 5. Motor Operation: Set MD1/DC11, MD2/DC12 and STP/DC22 terminals according to the purpose. 6. Other Setting (See Application Note for detail) i. ATT1, ATT2: Motor current attenuation. ii. EMM: Short circuit protection mode change. iii. RST: Not performed iv. OE: Output enable. [Setting for External Component Value] 1. Constant Current (100%) At VREF=1.5V Iout =VREF [V] / 5 / RF [Ω] =1.5 [V] / 5 / 0.22 [Ω] =1.36 [A] 2. Chopping frequency setting. 62.5kHz (RCHOP=20kΩ) 3. Short Protection Latch Time Tscp =CEM [pF] × Vt[V] / Ichg [µA] =100 [pF] × 1 [V] / 10 [µA] =10 [µS] 39/41 LV8740V Application Note Warning: ●Power supply connection terminal [VM, VM1, VM2] Make sure to short-circuit VM, VM1 and VM2.For controller supply voltage, the internal regulator voltage of VREG5 (typ 5V) is used. Make sure that supply voltage does not exceed the absolute MAX ratings under no circumstance. Noncompliance can be the cause of IC destruction and degradation. Caution is required for supply voltage because this IC performs switching. The bypass capacitor of the power supply should be close to the IC as much as possible to stabilize voltage. Also if you intend to use high current or back EMF is high, please augment enough capacitance. ●GND terminal [GND, PGND1, PGND2, Exposed Die-Pad] Since GND is the reference of the IC internal operation, make sure to connect to stable and the lowest possible potential. Since high current flows into PGND, connect it to one-point GND. The exposed die-pad is connected to the board frame of the IC. Therefore, do not connect it other than GND. Independent layout is preferable. If such layout is not feasible, please connect it to signal GND. Or if the area of GND and PGND is larger, you may connect the exposed die pad to the GND. (The independent connection of exposed die pad to PGND is not recommended.) ●Internal power supply regulator terminal [VREG5] VREG5 is the power supply for logic (typ 5V). When VM supply is powered and ST is ”H”, VREG5 operates. Please connect capacitor for stabilize VREG5. The recommendation value is 0.1uF. Since the voltage of VREG5 fluctuates, do not use it as reference voltage that requires accuracy. ●Input terminal The logic input pin incorporates pull-down resistor (100kΩ). When you set input pin to low voltage, please short it to GND because the input pin is vulnerable to noise. The input is TTL level (H: 2V or higher, L: 0.8V or lower). VREF pin is high impedance. ●OUT terminal [OUT1A, OUT1B, OUT2A, OUT2B] During chopping operation, the output voltage becomes equivalent to VM voltage, which can be the cause of noise. Caution is required for the pattern layout of output pin. The layout should be low impedance because driving current of motor flows into the output pin. Output voltage may boost due to back EMF. Make sure that the voltage does not exceed the absolute MAX ratings under no circumstance. Noncompliance can be the cause of IC destruction and degradation. ●Current sense resistor connection terminal [RF1, RF2] To perform constant current control, please connect resistor to RF pin. To perform saturation drive (without constant current control), please connect RF pin to GND. If RF pin is open, then short protector circuit operates. Therefore, please connect it to resistor or GND. The motor current flows into RF – GND line. Therefore, please connect it to common GND line and low impedance line. ●NC terminal NC pin is not connected to the IC. If VM line and output line are wide enough in your layout, please use NC 40/41 LV8740V Application Note ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. 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