CS3717A

CS3717A CHERRY | Alldatasheet

Document overview

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Technical content

Features

OUTA OUTB VDDBDIRECTIONIN1IN0 VCC VREF Gnd MONO- STABLE 105W 223W 223W 6KW 00 01 10 11 n Full/Half /Quarter Step Operation n Output Current Up to 1 A n Motor Supply Voltage 10V to 46V n Integrated Bootstrap Lowers Saturation Voltage n Built In Protection Diodes n Externally Selectable Current Level n Digital or Analog Control of Output Current Level n Thermal Overload Protection n Minimum External Components Package Options CS3717A 1A H-Bridge Stepper Motor Driver CS3717A

Description

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 cur- rent flow. A monostable, pro- grammed by an external RC net- work, sets the current decay time. 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 inser- tion of a sensing resistor. Two CS3717AÕs and several external components form a complete step- per motor drive subsystem. The recommended operating ambi- ent temperature range is from 0 to 70¡C. The CS3717A is supplied in a 16 lead PDIP. Block Diagram 16L PDIP (Internally Fused Leads) 1OUTB Pulse VDDB Gnd VCC IN1 DIRECTION Sense OUTA VDDA Gnd Gnd VREF Comp In IN0 Gnd CC Lead Temperature Soldering Absolute Maximum Ratings Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com A Company ¨ Rev. 4/29/99

Electrical Characteristics: Refer to the test circuit VDD = 36V, VCC = 5V, TA = 25¡C; unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT CS3717A Supply Voltage 10 46 V Logic Supply Voltage 4.75 5.25 V Logic Supply Current 7 15 mA Reference Input Current V REF = 5V 0.75 1.00 mA n Logic Inputs Input Low Voltage 0.8 V Input High Voltage 2 V Low Voltage Input Current V IN = 0.4V (DIRECTION) -100 µA (IN0, IN1) -400 µA High Voltage Input Current V IN = 2.4V 10 µA n Comparators Comparator Low V REF = 5V IN0 = Low 66 80 94 mV Threshold Voltage IN1 = High Comparator Medium V REF = 5V IN0 = High 236 251 266 mV Threshold Voltage IN1 = Low Comparator High V REF = 5V IN0 = Low 396 416 436 mV Threshold Voltage IN1 = Low Comparator Input Current ±20 µA Cutoff Time R T = 56k½ C T = 820pF 27 37 µs Turn Off Delay 2µ s Output Leakage Current IN0 =IN1 = High 100 µA n Source Diode-Transistor Pair Saturation Voltage I MOTOR = -0.5A conduction period 1.7 2.1 V recirculation period 1.10 1.35 V Saturation Voltage I MOTOR = -1A conduction period 2.1 2.8 V recirculation period 1.7 2.5 V Leakage Current V S = 46V 300 µA Diode Forward Voltage I MOTOR = -0.5A 1.00 1.25 V IMOTOR = -1A 1.3 1.7 V n Sink Diode-Transistor Pair Saturation Voltage I MOTOR = 0.5A 1.20 1.45 V IMOTOR = 1A 1.75 2.30 V Leakage Current V S = 46V 300 µA Diode Forward Voltage I MOTOR = 0.5A 1.1 1.5 V IMOTOR = 1A 1.4 2.0 V

PACKAGE PIN # PIN SYMBOL FUNCTION CS3717A Truth Table IN0 IN1 Output Current H H No Current L H Low Current H L Medium Current L L High Current 16L (Internally Fused Leads) 1 OUT B Output connection with OUTA. The output stage is a ÒHÓ 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 OFF = 0.69 RTCT). 3V DDB Supply voltage input for half output stage. 4, 5, 12, 13 Gnd Ground connection. Also conducts heat from die to printed circuit copper. 6V CC Supply voltage input for logic circuitry.

7 IN1 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.

8 DIRECTION 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 out- put stage short circuits during switching. 9 IN0 See IN1. Comp In Input connected to the three comparators. The voltage across the sense resistor is fed back to this input through the low pass filter R CCC. 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 R TCT, tOFF = 0.69 RTCT.

11 V REF A voltage applied to this pin sets the reference voltage of the

three comparators, thus determining the output current (also dependent on R Sense and the two inputs IN 0 and IN 1). 14 V DDA Supply voltage input for half output stage. 15 OUT A See OUTB.

16 Sense Connection to lower emitters of output stage for insertion of

current sense resistor.

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. Full step operation Both windings of the stepper motor are energized all the time with the same current I MA = 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. Typical Performance Characteristics Source Saturation Voltage vs. Output Current (Conduction Period) Source Saturation Voltage vs. Output Current (Recirculation Period) CS3717A VCE SAT (V) 0.2 0.4 0.6 0.8 I (A) VCE SAT (V) 0.2 0.4 0.6 0.8 I (A) Comparator Threshold vs. Junction TemperatureSink Saturation Voltage vs. Output Current VSAT (V) 0.2 0.4 0.6 0.8 I (A) VCX (%) 40 160 TJ (C) 100 60 80 100 120 14020 The application diagram shows a typical application in which two CS3717A's control a two phase bipolar stepper motor. Programming The amplitude of the current flowing in the motor wind- ing 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 ÒDirectionÓ 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 V CC or (Gnd) as appropriate to avoid noise problems. The current levels can be varied continuously by changing VREF.

Application Information

For rotation in the other direction the sequence must be reversed. The torque of each step is constant in full step operation. Half step operation Power is applied alternately to one winding then both according to the sequence: 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. Quarter step operation It is preferable to realize the quarter step operation at full power otherwise the steps will be of very irregular size. The extra quarter steps are added to the half step sequence by putting one coil on half current 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 over- heating. 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. Application Information: continued IN0A FULL STEP MOTOR DRIVE 1M = 500mA HALF STEP MOTOR DRIVE 1M = 250mA STAND BY WITH HOLDING TORQUE 1M = 80mA IN1A DIRECTIONA DIRECTIONB IN0B IN1B 500 mA IMA 500 mA IMB - 500 mA - 500 mA 12345678 IN OUT Input and Output Sequences for Half Step and Full Step Operation CS3717A L @ L M1 C @ 4 ¥ 1010 L C OUTA CS3717A OUTB L MOTOR WINDING M, RM)

+36V VCC Logic Supply +5V VREF Reference Voltage +5V 1kW RC RSENSE VRSVC CC 820 pF56kW RTCT 820 pF Gnd SenseComp InGndPulse DIRECTION IN0 IN1 VDDA OUTA OUTB Logic Control Inputs CS3717A Motor WindingL L @ 10mH R @ 13W VDDB Waveforms with MA Regulating (Phase = 0) VMOTOR TON TOFF t VCC VOUT B VOUT A t VDD VComp In t VCX VSENSE t VCX TD VF VSAT VSAT REC VSAT COND CS3717A

(Internally Fused Leads) D Lead Count Metric English Max Min Max Min 16L PDIP 19.69 18.67 .775 .735 (Internally Fused Leads) 8Rev. 4/29/99

16 Lead PDIP

Thermal Data (Internally Fused Leads) RQJC typ 15 ûC/W RQJA typ 50 ûC/W Package Specification PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA

Ordering Information

© 1999 Cherry Semiconductor Corporation Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. Plastic DIP (N); 300 mil wide 0.39 (.015) MIN. 1.14 (.045) D Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. .203 (.008) .356 (.014) REF: JEDEC MS-001 3.68 (.145) 2.92 (.115) 8.26 (.325) 7.62 (.300) 7.11 (.280) 6.10 (.240) .356 (.014) .558 (.022)