CS3717A DE SI GN CS3717A 1A H-Bridge Stepper Motor Driver Description NE W The power section is a full H-bridge driver with four internal clamp diodes for current recirculation. An external connection to the lower emitters is available for the insertion of a sensing resistor. Two CS3717A’s and several external components form a complete stepper motor drive subsystem. The recommended operating ambient temperature range is from 0° to 70°C. The CS3717A is supplied in a 16 lead PDIP. RE CO MM EN DE D AR CH IF V OR E The CS3717A controls and drives one phase of a bipolar stepper motor with chopper control of the phase current. Current levels may be selected in three steps by means of two logic inputs which select one of three current comparators. When both of these inputs are high the device is disabled. A separate logic input controls the direction of current flow. A monostable, programmed by an external RC network, sets the current decay time. Absolute Maximum Ratings Power Supply Voltage (VDDA, VDDB)............................................................50V Logic Supply Voltage (VCC) .............................................................................7V Logic Input Voltage (IN0, IN1, DIRECTION) ...............................................6V Comparator Input............................................................................................VCC Reference Input Voltage..................................................................................15V Output Current (DC Operation)...................................................................1.2A Storage Temperature .................................................................–55°C to +150°C Operating Junction Temperature ............................................–40°C to +150°C Lead Temperature Soldering Wave Solder(through hole styles only) ...........10 sec. max, 260°C peak Block Diagram IN1 NO T IN0 VCC VREF 01 10 DE VI CE 00 6KΩ 223Ω 223Ω DIRECTION VDDA OUTA OUTB VDDB 11 + Features ■ Full/Half /Quarter Step Operation ■ Output Current Up to 1 A ■ Motor Supply Voltage 10V to 46V ■ Integrated Bootstrap Lowers Saturation Voltage ■ Built In Protection Diodes ■ Externally Selectable Current Level ■ Digital or Analog Control of Output Current Level ■ Thermal Overload Protection ■ Minimum External Components Package Options 16L PDIP (Internally Fused Leads) OUTB 1 Sense Pulse OUTA VDDB VDDA Gnd Gnd Gnd Gnd - VCC VREF + IN1 Comp In - DIRECTION + IN0 MONOSTABLE - 105Ω THERMAL SHUTDOWN Gnd Comp In Pulse Sense ON Semiconductor 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885–3600 Fax: (401)885–5786 N. American Technical Support: 800-282-9855 Web Site: www.cherry–semi.com December, 2001 - Rev. 4 1 CS3717A Electrical Characteristics: Refer to the test circuit VDD = 36V, VCC = 5V, TA = 25°C; unless otherwise specified. PARAMETER Supply Voltage Logic Supply Voltage Logic Supply Current Reference Input Current TEST CONDITIONS MIN TYP MAX UNIT 7 0.75 46 5.25 15 1.00 V V mA mA 0.8 V (DIRECTION) -100 V µA (IN0, IN1) -400 10 µA µA 10 4.75 VREF = 5V ■ Logic Inputs Input Low Voltage Input High Voltage Low Voltage Input Current High Voltage Input Current 2 VIN = 0.4V VIN = 2.4V ■ Comparators Comparator Low Threshold Voltage Comparator Medium Threshold Voltage Comparator High Threshold Voltage Comparator Input Current Cutoff Time VREF = 5V RT = 56kΩ Turn Off Delay Output Leakage Current IN0 =IN1 = High VREF = 5V VREF = 5V IN0 = Low IN1 = High IN0 = High IN1 = Low IN0 = Low IN1 = Low 66 80 94 mV 236 251 266 mV 396 416 436 mV CT = 820pF 27 ±20 37 µA µs 2 100 µs µA ■ Source Diode-Transistor Pair Saturation Voltage IMOTOR = -0.5A conduction period recirculation period IMOTOR = -1A conduction period recirculation period VS = 46V 1.7 1.10 2.1 1.7 2.1 1.35 2.8 2.5 300 V V V V µA IMOTOR = -0.5A IMOTOR = -1A 1.00 1.3 1.25 1.7 V V Saturation Voltage IMOTOR = 0.5A IMOTOR = 1A 1.20 1.75 1.45 2.30 V V Leakage Current VS = 46V 300 µA Diode Forward Voltage IMOTOR = 0.5A IMOTOR = 1A 1.5 2.0 V V Saturation Voltage Leakage Current Diode Forward Voltage ■ Sink Diode-Transistor Pair 1.1 1.4 2 IN0 IN1 Output Current H H No Current L H Low Current H L Medium Current L L High Current Package Pin Description PACKAGE PIN # PIN SYMBOL FUNCTION 16L (Internally Fused Leads) 1 OUT B Output connection with OUTA. The output stage is a “H” bridge formed by four transistors and four diodes suitable for switching applications. 2 Pulse A parallel RC network connected to this pin sets the OFF time of the lower power transistors. The pulse generator is a monostable triggered by the rising edge of the output of the comparators (tOFF = 0.69 RTCT). 3 VDDB Supply voltage input for half output stage. 4, 5, 12, 13 Gnd 6 VCC Ground connection. Also conducts heat from die to printed circuit copper. Supply voltage input for logic circuitry. 7 IN1 8 DIRECTION 9 IN0 10 Comp In 11 VREF A voltage applied to this pin sets the reference voltage of the three comparators, thus determining the output current (also dependent on RSense and the two inputs IN 0 and IN 1). 14 VDDA Supply voltage input for half output stage. 15 OUT A 16 Sense This pin and IN0 are logic inputs which select the outputs of the three comparators to set the current level. Current also depends on the sensing resistor and reference voltage. See truth table. This TTL-compatible logic input sets the direction of current flow through the load. A high level causes current to flow from OUTA (source) to OUTB (sink). A Schmitt trigger on this input provides good noise immunity and a delay circuit prevents output stage short circuits during switching. See IN1. Input connected to the three comparators. The voltage across the sense resistor is fed back to this input through the low pass filter RCCC. The lower power transistors are disabled when the sense voltage exceeds the reference voltage of the selected comparator. When this occurs the current decays for a time set by RTCT, tOFF = 0.69 RTCT. See OUTB. Connection to lower emitters of output stage for insertion of current sense resistor. 3 CS3717A Truth Table CS3717A Typical Performance Characteristics Source Saturation Voltage vs. Output Current (Conduction Period) 4 4 3 3 VCE SAT (V) VCE SAT (V) Source Saturation Voltage vs. Output Current (Recirculation Period) 2 1 2 1 0 0.2 0.4 0.6 0 0.8 0.2 0.4 0.6 0.8 I (A) I (A) Sink Saturation Voltage vs. Output Current Comparator Threshold vs. Junction Temperature 3 100 2 VCX (%) VSAT (V) 4 1 80 60 40 20 0 0 0.2 0.4 0.6 0.8 20 40 60 80 100 120 140 160 TJ (C) I (A) Application Information The application diagram shows a typical application in which two CS3717A's control a two phase bipolar stepper motor. Control of the motor The stepper motor can rotate in either direction according to the sequence of the input signals. It is possible to obtain a full step, a half step and quarter step operation. Programming The amplitude of the current flowing in the motor winding is controlled by the logic inputs IN0 and IN1. The truth table (page 3) shows three current levels and an off state. A high level on the “Direction” logic input sets the direction of that current from OUTA to OUTB; a low level from OUTB to OUTA. It is recommended that unused inputs are tied to VCC or (Gnd) as appropriate to avoid noise problems. The current levels can be varied continuously by changing VREF. Full step operation Both windings of the stepper motor are energized all the time with the same current IMA = IMB. IN0 and IN1 remain fixed at whatever torque value is required. Calling A the condition with winding A energized in one direction and A in the other direction, the sequence for full step rotation is: AB→AB→AB→AB etc. 4 For rotation in the other direction the sequence must be reversed. The extra quarter steps are added to the half step sequence by putting one coil on half current according to the sequence. The torque of each step is constant in full step operation. B A A AB→ B→B→ B→ AB→ A → A etc. 2 2 2 Half step operation Power is applied alternately to one winding then both according to the sequence: Motor selection As the CS3717A provides constant current drive with a switching operation, care must be taken to select stepper motors with low hysteresis losses to prevent motor overheating. AB→B→AB→A→AB→B→AB→A etc. Like full step this can be done at any current level; the torque is not constant but is lower when only one winding is energized. A coil is turned off by setting IN0 and IN1 both high. L-C filter To reduce EMI and chopping losses in the motor, a low pass L-C filter can be inserted across the outputs of the CS3717A as shown in the following diagram. Quarter step operation It is preferable to realize the quarter step operation at full power otherwise the steps will be of very irregular size. Input and Output Sequences for Half Step and Full Step Operation L OUTA CS3717A MOTOR WINDING (LM, RM) C OUTB L≅ C≅ 1 LM 10 STAND BY WITH HOLDING TORQUE 1M = 80mA HALF STEP MOTOR DRIVE 1M = 250mA 1 2 3 4 5 6 IN0A IN1A IN DIRECTIONA DIRECTIONB IN0B IN1B 500 mA IMA OUT - 500 mA 500 mA IMB - 500 mA 5 7 8 4 • 1010 L FULL STEP MOTOR DRIVE 1M = 500mA CS3717A Application Information: continued CS3717A Test Circuit Reference Voltage +5V IN1 Logic Control Inputs Logic Supply +5V VREF Motor Supply +36V VDDB VDDA VCC L ≅ 10mH R ≅ 13Ω OUTA CS3717A IN0 DIRECTION Pulse Gnd OUTB Comp In Sense VC CT CC RT 820 pF 820 pF 56kΩ Motor Winding L RC 1kΩ VRS RSENSE 1Ω Gnd Waveforms with MA Regulating (Phase = 0) VCX VSENSE 0V VCX t TD VComp In 0V t VDD VOUT A VF VSAT 0V VSAT REC VCC VOUT B VMOTOR t VSAT COND TON TOFF t 0V 6 CS3717A Application Circuit - Two Phase Bipolar Stepper Motor Driver VSS 0.1µF C3 VS C1 100µF C2 0.1µF VREF IN1 VDD VCC B VDD MAA A OUTA CS3717A CS-3717A IN0 DIRECTION Gnd Pulse Gnd MBA OUTB Sense COMP IN RC 1kΩ FROM µ PROCESSOR 820pF 1Ω RSense 820pF CT RT 56kΩ CC CT RT 56kΩ CC 820pF 1Ω RSense 820pF RC IMA IMB 1kΩ Gnd Gnd Pulse STEPPER MOTOR Sense Comp In Out B DIRECTION CS3717A IN1 IN0 VREF VDD VCC B OutA VDD A Mounting Instructions (see fig. 1). In addition, it is possible to use an external heatsink (see fig. 3). During soldering the pins temperature must not exceed 260°C and the soldering time must not be longer than 12 seconds. The external heatsink or printed circuit copper area must be connected to electrical ground. The RΘJA of the CS3717A can be reduced by soldering the Gnd pins to a suitable copper area of the printed circuit board or to an external heatsink. The diagram of fig. 2 shows the maximum dissipated power Ptot and the RΘJA as a function of the side “l ” of two equal square copper areas having a thickness of 35µ Ptot (W) COPPER AREA 35µ THICKNESS Rθ JA (˚C/W) 80 4 Rθ JA 3 l 60 40 2 Ptot (Tamb = 70˚C) 1 20 l 0 P.C. BOARD 0 10 20 30 0 I(mm) 40 “l” Figure 1 - Example of P.C. Board Copper Area Which is Used as Heatsink with 16 lead fused package. Figure 2 - Max. Power Dissipation And Junction To Ambient Thermal Resistance vs. Size “l” for 16 lead fused package. Ptot (W) 170mm HE IN AT - TH 4 WI 5 FIN SIN ITH R th = 50 100 K 0 SIN E AIR AT Figure 3 - External Heatsink Mounting Example (Rth = 30°C/W) for 16 lead batwing package. /W FRE 1 0 -50 25 ˚C 2 38.0mm HE 11.9mm ITE KW 3 Tamb (C) Figure 4 - Maximum Allowable Power Dissipation vs. Ambient Temperature for 16 lead batwing package. 7 PACKAGE THERMAL DATA PACKAGE DIMENSIONS IN mm (INCHES) D Metric Max Min 19.69 18.67 16L PDIP (Internally Fused Leads) 16 Lead PDIP Thermal Data RΘJC typ RΘJA typ English Max Min .775 .735 Plastic DIP (N); 300 mil wide 1.77 (.070) 1.14 (.045) AR CH IF V OR E 8.26 (.325) 7.62 (.300) 3.68 (.145) 2.92 (.115) °C/W °C/W 2.54 (.100) BSC 0.39 (.015) MIN. RE CO MM EN DE D .356 (.014) .203 (.008) 15 50 NE W 7.11 (.280) 6.10 (.240) (Internally Fused Leads) DE SI GN Lead Count .558 (.022) .356 (.014) D Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. NO T REF: JEDEC MS-001 DE VI CE CS3717A Package Specification ON Semiconductor and the ON Logo are trademarks of Semiconductor Components Industries, LLC (SCILLC). ON Semiconductor reserves the right to make changes without further notice to any products herein. For additional information and the latest available information, please contact your local ON Semiconductor representative. Ordering Information Part Number CS3717AGNF16 Description 16 Lead PDIP (Internally Fused Leads) 8 © Semiconductor Components Industries, LLC, 2000