L9935 Two-phase stepper motor driver Features ■ 2 x 1.1 A full bridge outputs ■ Integrated chopping current regulation ■ Minimized power dissipation during flyback ■ Output stages with controlled output voltage slopes to reduce electromagnetic radiation '!0'03 PowerSO20 ■ Short-circuit protection of all outputs ■ Error-flag for over load, open load and over temperature pre alarm ■ Delayed channel switch on to reduce peak currents Description ■ Max.
Contents L9935 Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Thermal data . . . . . . . . . . . . . . .
L9935 Contents 5.14 Test condition for all propagation times . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.15 Cascading several devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 5.16 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.17 Electromagnetic emission classification (EME) . . . . . . . . . . . . . . . . . . . . 25 6 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . .
List of tables L9935 List of tables Table 1. Table 2. Table 3. Table 4. Table 5. Table 6. Table 7. Table 8. Table 9. Table 10. Table 11. Table 12. Table 13. 4/29 Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Pin function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . .
L9935 List of figures List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pin connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 General application circuit proposal . . . . . .
Block diagram 1 L9935 Block diagram Figure 1. '.$ Block diagram ^ /54! $2)6%2 ,/')# 3#+ 3$) 3$/ 6## #3. %. /54" /3#),,!4/2 32! /54! . # 63 /3# #/--/. ,/')# $)!'./34)# ")!3).' #$26 $2)6%2 ,/')# '.$ '.$ ^ /54" 32" '.
L9935 2 Pin description Pin description Figure 2. Pin connection (top view) '.$ '.$ /54! 32! 3#+ /54! 3$) . # 3$/ 63 6## /3# #3. #$26 %. /54" /54" 32" '.$ '.$ '!0'03 Table 2.
Electrical specifications L9935 3 Electrical specifications 3.1 Absolute maximum ratings Table 3. Absolute maximum ratings Symbol VS VSPulsed Parameter Value Unit DC supply voltage -0.3 to 35 V Pulsed supply voltage T < 400 ms -0.3 to 40 V internally clamped to VS or GND depending on the current direction VOUT (Ai/Bi) Output voltages IOUT (Ai/Bi) DC output currents Peak output currents (T/tp 10) VSRA/SRB VCC VCDRV 1.2 2.5 A A Sense resistor voltages -0.3 to 6.
L9935 3.3 Electrical specifications Electrical characteristics 8 V VS 24 V; -40 °C Tj 150 °C; 4.5 V VCC 5.5 V, unless otherwise specified. Parameters are tested at 125 °C. Values at 140 °C are guaranteed by design and correlation. Table 5. Electrical characteristics Symbol Parameter Test condition Min. Typ. Max.
Electrical specifications Table 5. L9935 Electrical characteristics (continued) Symbol Parameter Test condition Min. Typ. Max. Unit IHIGH High input current VHigh = VCC -10 0 10 A ILow Low input current VLow = 0 V -3 -10 -30 A 0.17 VCC V Logic outputs (SDO) VCC- VSDO,High High output voltage ISDO = -1 mA VCC-1 VSDO,Low Low output voltage ISDO = 1 mA - 0.17 1 V VOSC, H High peak voltage EN = LOW 2.2 2.46 2.6 V VOSC, L Low peak voltage EN = LOW 1 1.23 1.
L9935 Application hints 4 Application hints Figure 3. General application circuit proposal '.$ ^ '.$ 32! 2 7 /54! $2)6%2 ,/')# /54! . # 3$) ).4%2&!#% 3#+ 3$) 3$/ #3. M# %. 6## /54" 6 63 /3#),,!4/2 #/--/. ,/')# /3# #/3# N& $)!'./34)# ")!3).' #$RIVER N& #$26 # N& 34%00%2 -/4/2 0/7%2 3500,9 # M& N& '.$ $2)6%2 ,/')# ^ /54" 32" '.
Functional description L9935 5 Functional description 5.1 Basic structure The L9935 is a dual full bridge driver for inductive loads with a chopper current regulation. Outputs A1 and A2 belong to full bridge A Outputs B1 and B2 belong to full bridge B. The polarity of the bridges can be controlled by bit0 and bit3 (for full bridge A, bit3, for full bridge B, bit0). Bit5, bit4 (for full bridge A) and bit2, bit1 (for full bridge B) control the currents. Bit3 high leads to output A1 high.
L9935 5.2 Functional description Full bridge function Figure 5. Displays a full bridge including the current sense circuit. 63 - - $ $ $ ! ! BIT BIT $2)6% ,/')# - $ BIT BIT BIT BIT #522%.4 ,/')# ).()")4 /. (( - ,/!$ $ #/-0 T $ $ $ 2 2 %84%2.!, 3%.3% 2%3)34/2 #522%.4 !$*534 '!0'03 5.2.
Functional description 5.2.4 L9935 Reversing phase Suppose the current flowed via M21, the load and M12 before reversing phase. Reversing phase M21 and M12 will be turned off. So now the current will flow through D22, the load and D11. This leads to a fast current decay. 5.2.5 Chopper control by oscillator Both chopping circuits work with offset phase.
L9935 Functional description Figure 7. Pulse diagram to explain offset chopping 6/3# CURRENT THRESHOLD 632! CURRENT THRESHOLD 632" TURN OFF DELAY DUE TO SLOPE VELOCITY CONTROL TOTAL CURRENT CONSUMPTION )63 $) '!0'03 Using offset chopping the changes of the supply current remain half as large as using non offset chopping. Turning off the oscillator for example by shorting pin OSC to ground will hinder turning on of the bridges anymore after the comparators have generated a turn off signal.
Functional description L9935 next data transfer took place. After detection of a short to VS we suggest to turn off the corresponding bridge to reduce power dissipation for at least 1ms. 5.5 Diagnosis of a short to VS During the short current through the sink transistor will rise more rapidly than under normal load conditions. Reaching a peak current of 1.5 times the maximum PWM current between typically 2 µs and 5 µs after turn on will be detected as a short to VS.
L9935 5.6 Functional description Short from an output to ground The current through the short will be detected by the protection of the source transistor. The source transistor will turn off exceeding a current of typically 1.8 A. Minimum overload detection current is 1.2 A. To obtain proper current regulation (by the sink transistors and not by source transistor shut down) the maximum current of the PWM regulator should be set to a maximum value of 1.1 A. 5.
Functional description 5.10.1 L9935 Over temperature pre alarm Typically 20K before thermal shut down takes place an over temperature pre alarm (bit7 and bit6 low) takes place. Typically over temperature pre alarm temperature is between 150 °C and 160 °C. 5.11 Application hints using a high resistive stepper motor The L9935 was originally targeted on stepper chopping stepper motor application with typical resistances of 8..12 .
L9935 5.12 Functional description Limitation of the diagnosis The diagnosis depends on either detecting an overcurrent of more than typically 1.8 A through the source transistor or on not detecting a flyback pulse, or on detecting severe overcurrents of the sink transistor immediately after turn on. ● Small currents bypassing the load will not be detected.
Functional description 5.13.1 L9935 Startup of the serial data interface Falling slope of EN activates the device. After ten.sck the device is ready to work. Falling slope of CSN indicates start of frame. Data transfer (reading SDI into the register) takes place at the rising slopes of SCK. Data transfer of the register to SDO takes place at the falling slope of SCK. Rising slope of CSN indicates end of frame.
L9935 5.14 Functional description Test condition for all propagation times Unless otherwise specified) HIGH 3 V; LOW 0.8 V; tr, tf = 10 ns; Enable: ENN Low < 0.8 V, ENN High > VCC -0.8 V Table 9. Test condition for all propagation times Symbol fSCLK Parameter Test conditions Min. Typ. Max.
Functional description 5.15 L9935 Cascading several devices Cascading several devices can be done using the SDO output to pass data to the next device. The whole frame now consists of n byte. n is the number of devices used. Figure 10. Cascading several stepper motor drivers NO 3$/ 3$) NO 3$/ 3$) NO 3$/ 3$) 3$/ M0 #3. 3#+ 3#+ #3. 3#+ #3. 3#+ #3. '!0'03 Figure 11. Control sequence for 3 Stepper motor drivers %. #3.
L9935 Functional description 5.16 Application information For driving a stepper motor we suggest to use the following codes. The columned ’SDO correct’ shows the data returned at SDO in correct function. The columns presented under ’Error cases’ display the diagnosis bits if errors are detected. Examples of control sequences. Table 10.
Functional description Table 11. L9935 Half step mode control sequences and diagnosis response SDI SDO Error cases and SDObit7, bit6 - - O P E N B O P E N A1 A2 B1 B2 S H O R T S H O R T S H O R T S H O R T VS VS VS VS A1 A2 B1 B2 (1) (1) (1) (1) S H O R T S H O R T S H O R T S H O R T therm. therm.
L9935 5.17 Functional description Electromagnetic emission classification (EME) Electromagnetic emission classes presented below are typical data found on bench test. For detailed test description please refer to ’Electromagnetic Emission (EME) Measurement of Integrated Circuits, DC to 1GHz’ of VDE/ZVEI work group 767.13 and VDE/ZVEI work group 767.14 or IEC project number 47A 1967Ed. This data is targeted to board designers to allow an estimation of emission filtering effort required in application.
Functional description L9935 Figure 14. EMC compatibility for L9935 ( 6BATT N& N& & 6S /UT /UT BIPOLAR STEPPER MOTOR /UT /UT '.
L9935 6 Package information Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 15. PowerSO20 mechanical data and package dimensions $)- MM -). 490 ! A INCH -!8 -).
Revision history 7 L9935 Revision history Table 13. 28/29 Document revision history Date Revision Changes 13-Apr-2003 6 Initial release. 02-Aug-2006 7 Updated at the new corporate template. Corrected the Figure 14. 11-Dec-2008 8 Updated Figure 2: Pin connection (top view) on page 7. Updated Section 6: Package information on page 27. 04-Apr-2011 9 Updated Section 5.10: Open load on page 17. 18-sEP-2013 10 Updated Disclaimer.
L9935 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale.
