2-Phase Stepper-Motor Driver TCA 3727 Overview Bipolar IC Features * 2 x 0.75 amp. / 50 V outputs * Integrated driver, control logic and current control (chopper) * Fast free-wheeling diodes * Max. supply voltage 52 V * Outputs free of crossover current * Offset-phase turn-ON of output stages * Z-diode for logic supply * Low standby-current drain * Full, half, quarter, mini step P-DIP-20-6 P-DSO-24-3 Type Ordering Code Package TCA 3727 Q67000-A8302 P-DIP-20-6 TCA 3727 G Q67000-A8335 P-DSO-24-3 Description TCA 3727 is a bipolar, monolithic IC for driving bipolar stepper motors, DC motors and other inductive loads that operate on constant current. The control logic and power output stages for two bipolar windings are integrated on a single chip which permits switched current control of motors with 0.75 A per phase at operating voltages up to 50 V. Semiconductor Group 1 1998-12-16 TCA 3727 The direction and value of current are programmed for each phase via separate control inputs. A common oscillator generates the timing for the current control and turn-on with phase offset of the two output stages. The two output stages in a full-bridge configuration have integrated, fast free-wheeling diodes and are free of crossover current. The logic is supplied either separately with 5 V or taken from the motor supply voltage by way of a series resistor and an integrated Z-diode. The device can be driven directly by a microprocessor with the possibility of all modes from full step through half step to mini step. TCA 3727 TCA 3727 G 10 1 20 20 11 2 19 21 Phase 1 3 18 Phase 2 OSC 4 17 Inhibit GND 5 16 GND GND 6 15 GND Q11 7 14 Q21 R1 8 13 R2 VS 9 12 VL Q12 10 11 Q22 10 11 Phase 1 OSC GND GND GND GND Q11 R1 + VS Q12 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 20 21 Phase 2 Inhibit GND GND GND GND Q21 R2 +VL Q22 IEP00898 IEP00696 Figure 1 Pin Configuration (top view) Semiconductor Group 2 1998-12-16 TCA 3727 Pin Definitions and Functions Pin No. Function 1, 2, 19, 20 (1, 2, 23, 24) 1) Digital control inputs IX0, IX1 for the magnitude of the current of the particular phase. IX1 IX0 Phase Current Example of Motor Status H H 0 No current H L 1/3 Imax Hold LH 2/3 Imax Set LL Imax Accelerate typical Imax with Rsense = 1 : 750 mA 3 Input Phase 1; controls the current through phase winding 1. On H-potential the phase current flows from Q11 to Q12, on L-potential in the reverse direction. 5, 6, 15, 16 (5, 6, 7, 8, 17, 18, 19, 20) 1) Ground; all pins are connected internally. 4 Oscillator; works at approx. 25 kHz if this pin is wired to ground across 2.2 nF. 8 (10) 1) Resistor R1 for sensing the current in phase 1. 7, 10 (9, 12) 1) Push-pull outputs Q11, Q12 for phase 1 with integrated free-wheeling diodes. 9 (11) 1) Supply voltage; block to ground, as close as possible to the IC, with a stable electrolytic capacitor of at least 10 F in parallel with a ceramic capacitor of 220 nF. 12 (14) 1) Logic supply voltage; either supply with 5 V or connect to + VS across a series resistor. A Z-diode of approx. 7 V is integrated. In both cases block to ground directly on the IC with a stable electrolytic capacitor of 10 F in parallel with a ceramic capacitor of 100 nF. 11, 14 (13, 16) 1) Push-pull outputs Q22, Q21 for phase 2 with integrated free wheeling diodes. 13 (15) 1) Resistor R2 for sensing the current in phase 2. Semiconductor Group 3 1998-12-16 TCA 3727 Pin Definitions and Functions (cont'd) Pin No. Function 17 (21) 1) Inhibit input; the IC can be put on standby by low potential on this pin. This reduces the current consumption substantially. 18 (22) 1) Input phase 2; controls the current flow through phase winding 2. On H-potential the phase current flows from Q21 to Q22, on L potential in the reverse direction. 1) TCA 3727 G only Semiconductor Group 4 1998-12-16 TCA 3727 + VL 12 4 + VS 9 OSC 7 10 1 11 2 Phase 1 3 Inhibit 17 Phase 1 10 Function Logic Phase 1 8 R1 Q21 20 21 19 Phase 2 18 Phase 2 11 Function Logic Phase 2 13 5, 6, 15, 16 GND Figure 2 Q12 Inhibit 14 20 Q11 Q22 R2 IEB00697 Block Diagram TCA 3727 Semiconductor Group 5 1998-12-16 TCA 3727 + VL 14 4 + VS 11 Oscillator D11 D12 T11 10 T12 Q11 1 Phase 1 D13 11 2 Phase 1 3 Inhibit 21 Functional Logic Phase 1 D14 T13 T14 Q12 R1 Inhibit D21 20 12 10 D22 T21 T22 16 Q21 24 Phase 2 D23 21 23 Phase 2 22 Functional Logic Phase 2 T23 D24 T24 13 15 5-8, 17-19 GND Figure 3 9 Q22 R2 IEB00899 Block Diagram TCA 3727 G Semiconductor Group 6 1998-12-16 TCA 3727 Absolute Maximum Ratings TA = - 40 to 125 C Parameter Symbol Limit Values Unit Remarks min. max. VS Logic supply voltage VL Z-current of VL IL IQ Output current IGND Ground current VIxx Logic inputs R1 , R2, oscillator input voltage VRX, VOSC Junction temperature Tj Tj Storage temperature Tstg Supply voltage Semiconductor Group 0 52 V - 0 6.5 V Z-diode - 50 mA - -1 1 A - -2 2 A - VL + 0.3 V - 0.3 VL + 0.3 V -6 IXX ; Phase 1, 2; Inhibit - - - 125 150 C C - max. 10,000 h - 50 125 C - 7 1998-12-16 TCA 3727 Operating Range Parameter Symbol Limit Values Unit Remarks min. max. 5 50 V - Logic supply voltage VS VL 4.5 6.5 V without series resistor Case temperature TC - 40 110 C Supply voltage measured on pin 5 Pdiss = 2 W Output current Logic inputs IQ VIXX - 1000 1000 mA -5 VL V - IXX ; Phase 1, 2; Inhibit Thermal Resistances Junction ambient Rth ja Junction ambient Rth ja 2 (soldered on a 35 m thick 20 cm PC board copper area) Junction case Rth jc - - 56 40 K/W P-DIP-20-3 K/W P-DIP-20-3 - 18 K/W measured on pin 5 P-DIP-20-3 Rth ja Junction ambient Junction ambient Rth ja 2 (soldered on a 35 m thick 20 cm PC board copper area) Junction case Rth jc - - 75 50 K/W P-DSO-24-3 K/W P-DSO-24-3 - 15 K/W measured on pin 5 P-DSO-24-3 Semiconductor Group 8 1998-12-16 TCA 3727 Characteristics VS = 40 V; VL = 5 V; - 25 C Tj 125 C Parameter Symbol Limit Values min. typ. max. Unit Test Condition Current Consumption from + VS from + VS IS IS - - 0.2 16 0.5 20 mA mA Vinh = L Vinh = H IQ1/2 = 0, IXX = L Vinh = L Vinh = H IQ1/2 = 0, IXX = L from + VL from + VL IL IL - - 1.7 18 3 25 mA mA IOSC VOSCL VOSCH fOSC - - - 18 110 1.3 2.3 25 - - - 35 A V V kHz COSC = 2.2 nF Vsense n Vsense h Vsense s Vsense a - 200 460 740 0 250 540 825 - 300 620 910 mV mV mV mV IX0 = H; IX1 = H IX0 = L; IX1 = H IX0 = H; IX1 = L IX0 = L; IX1 = L Threshold VI - - IIL IIL IIH 2.3 (LH) - - 10 V L-input current L-input current H-input current 1.4 (HL) - 10 - 100 - A A A VI = 1.4 V VI = 0 V VI = 5 V Oscillator Output charging current Charging threshold Discharging threshold Frequency - - - Phase Current Selection (R1; R2) Current Limit Threshold No current Hold Setpoint Accelerate Logic Inputs (IX1 ; IX0 ; Phase x) Semiconductor Group 9 - - - 1998-12-16 TCA 3727 Characteristics (cont'd) VS = 40 V; VL = 5 V; - 25 C Tj 125 C Parameter Symbol Limit Values Unit Test Condition min. typ. max. 2 3 4 V - 1.7 2.3 2.9 V - VInhhy 0.3 0.7 1.1 V - VLZ 6.5 7.4 8.2 V IL = 50 mA 0.3 0.5 - 0.9 1 0.6 1 300 1.3 1.4 V V A V V IQ = - 0.5 A IQ = - 0.75 A VQ = 40 V IQ = 0.5 A IQ = 0.75 A Standby Cutout (inhibit) Threshold VInh (LH) Threshold VInh (HL) Hysteresis Internal Z-Diode Z-voltage Power Outputs Diode Transistor Sink Pair (D13, T13; D14, T14; D23, T23; D24, T24) Saturation voltage Saturation voltage Reverse current Forward voltage Forward voltage Vsatl Vsatl IRl VFl VFl - - - - - Diode Transistor Source Pair (D11, T11; D12, T12; D21, T21; D22, T22) Saturation voltage VsatuC - 0.9 1.2 V IQ = 0.5 A; Saturation voltage VsatuD - 0.3 0.7 V IQ = 0.5 A; charge Saturation voltage VsatuC - 1.1 1.4 V Saturation voltage VsatuD - 0.5 1 V Reverse current Forward voltage Forward voltage Diode leakage current IRu VFu VFu ISL - - - - - 1 1.1 1 300 1.3 1.4 2 A V V mA Semiconductor Group 10 discharge IQ = 0.75 A; charge IQ = 0.75 A; discharge VQ = 0 V IQ = - 0.5 A IQ = - 0.75 A IF = - 0.75 A 1998-12-16 TCA 3727 Quiescent Current IS, IL versus Supply Voltage VS Quiescent Current IS, IL versus Junction Temperature Tj IED01655 40 IED01656 40 mA mA S, L S, L T j = 25 C 30 V S = 40V 30 XX = L L 20 XX = H L 20 L XX = L L 10 10 XX = H S S 0 0 10 20 30 V VS 0 50 Output Current IQX versus Junction Temperature Tj QX 0 25 50 75 100 C 150 Tj Operating Condition: IED01657 800 -25 VL VInh COSC Rsense =5V =H = 2.2 nF =1 Load: L = 10 mH R = 2.4 fphase = 50 Hz mode: fullstep mA 600 400 200 0 -25 0 25 50 Semiconductor Group 75 100 C 150 Tj 11 1998-12-16 TCA 3727 Output Saturation Voltages Vsat versus Output Current IQ Forward Current IF of Free-Wheeling Diodes versus Forward Voltages VF F F IED01167 A 1.0 V Fl V Fu 0.8 A V V T j Fl= 25 C Fu 0.8 0.6 T j = 25 C 0.6 0.4 0.4 0.2 0.2 0 0 0 0 0.5 0.5 1.0 1.0 V V VF 1.5 1.5 VF Typical Power Dissipation Ptot versus Output Current IQ (Non Stepping) Permissible Power Dissipation Ptot versus Case Temperature TC IED01660 12 Measured at pin 5. W Ptot 10 P-DSO-24 8 6 P-DIP-20 4 2 0 -25 Semiconductor Group 12 0 25 50 75 100 125 C 175 Tc 1998-12-16 TCA 3727 Input Characteristics of Ixx, Phase X, Inhibit Input Current of Inhibit versus JunctionTemperature Tj IED01661 0.8 mA IXX 0.6 V L = 5V 0.4 0.2 0 0.2 0.4 0.6 0.8 -6 -5 -2 3.9 2 V 6 V IXX Oscillator Frequency fOSC versus Junction Temperature Tj IED01663 30 V S = 40V V L = 5V COSZ = 2.2nF kHz f OSC 25 20 15 -25 0 25 50 75 100 125 C 150 Tj Semiconductor Group 13 1998-12-16 TCA 3727 100 F 220 nF L H 1 10 2 11 3 17 S 12 9 VL 20 19 21 VS Q11 Inhibit Q21 Q22 13 OSC VOSC 8 R2 1 VSense 2.2 nF VSatu - VFu 7 Q - Fu 10 Q12 TCA 3727 Phase 2 OSC 4 100 F 220 nF VS Phase 1 20 18 V L V H L -R Ru VSatl 14 11 - VFl GND 5, 6 15, 16 R1 1 VSense GND IES00706 Figure 4 Test Circuit +5 V +40 V 100 F 1 2 3 Micro Controller 17 20 19 18 10 12 VL 3 VS Phase 1 Inhibit Q12 10 TCA 3727 Q21 20 21 Phase 2 OSC 4 7 Q11 11 2.2 nF 100 F 220 nF 220 nF Q22 13 R2 1 8 R1 1 14 11 M GND 5, 6 15, 16 IES00707 Figure 5 Application Circuit Semiconductor Group 14 1998-12-16 TCA 3727 Normal Mode Accelerate Mode H 10 L t H 11 L t H Phase 1 L t i acc i set Q1 t i set i acc i acc i set Q2 t i set i acc Phase 2 20 21 t H L t H L t H L IED01666 Figure 6 Full-Step Operation Semiconductor Group 15 1998-12-16 TCA 3727 Normal Mode Accelerate Mode 10 H L 11 H L t t H L Phase 1 t i acc i set Q1 t - i set - i acc i acc i set Q2 t - i set - i acc Phase 2 H L 20 H L 21 t t H L t IED01667 Figure 7 Half-Step Operation Semiconductor Group 16 1998-12-16 TCA 3727 Figure 8 Quarter-Step Operation Semiconductor Group 17 1998-12-16 TCA 3727 H 10 L t H 11 L t H Phase 1 L t i acc i set i hold Q1 t i hold i set i acc i acc i set i hold Q2 t i hold i set i acc Phase 2 20 21 H L t H L t H L t IED01665 Figure 9 Mini-Step Operation Semiconductor Group 18 1998-12-16 TCA 3727 V Osc 2.4 V 1.4 V 0 T t GND 0 t V Q12 + VS V FU V sat 1 0 t V Q11 V satu D + VS V satu C t V Q22 + VS 0 t V Q21 + VS t Operating conditions: VS VL L phase x R phase x V phase x V Inhibit V xx = 40 V =5V = 10 mH = 20 =H =H =L IED01177 Figure 10 Current Control Semiconductor Group 19 1998-12-16 TCA 3727 Inhibit L V Osc t 2.3 V 1.3 V 0 Oscillator High Imped. Oscillator High Imped. t Phase Changeover Phase 1 L GND t N 0 t V Fu V Q11 Vsatu C Vsatu D +V S High Impedance V Fl V satl High Impedance t V Q12 +V S High Impedance t Phase 1 Slow Current Decay Operating Conditions: = 40 V VS =5V V L phase 1 = 10 mH R phase 1 = 20 1X = L; 1X = H t Fast Current Decay Slow Current Decay Fast Current Decay by Inhibit IED01178 Figure 11 Phase Reversal and Inhibit Semiconductor Group 20 1998-12-16 TCA 3727 Calculation of Power Dissipation The total power dissipation Ptot is made up of saturation losses Psat (transistor saturation voltage and diode forward voltages), quiescent losses Pq (quiescent current times supply voltage) and switching losses Ps (turn-ON / turn-OFF operations). The following equations give the power dissipation for chopper operation without phase reversal. This is the worst case, because full current flows for the entire time and switching losses occur in addition. Ptot = 2 x Psat + Pq + 2 x Ps where Psat IN { Vsatl x d + VFu (1 - d ) + VsatuC x d + VsatuD (1 - d ) } Pq = Iq x VS + IL x VL V S i D x t DON i D + i R x t ON I N - + ------------------------------ + ----- t DOFF + t OFF P S ------ --------------------T 2 2 4 IN Iq iD iR tp tON tOFF tDON tDOFF T d Vsatl VsatuC VsatuD VFu VS VL IL = nominal current (mean value) = quiescent current = reverse current during turn-on delay = peak reverse current = conducting time of chopper transistor = turn-ON time = turn-OFF time = turn-ON delay = turn-OFFdelay = cycle duration = duty cycle tp/T = saturation voltage of sink transistor (T3, T4) = saturation voltage of source transistor (T1, T2) during charge cycle = saturation voltage of source transistor (T1, T2) during discharge cycle = forward voltage of free-wheeling diode (D1, D2) = supply voltage = logic supply voltage = current from logic supply Semiconductor Group 21 1998-12-16 TCA 3727 +V S Tx1 Dx1 Dx2 Tx2 L Tx3 Dx3 Dx4 Tx4 V sense R sense IES01179 Figure 12 Voltage and Current at Chopper Transistor Turn-ON Turn-OFF iR N iD VS + VFu VS + VFu Vsatl t D ON t D OFF t ON tp t OFF t IET01210 Figure 13 Semiconductor Group 22 1998-12-16 TCA 3727 Application Hints The TCA 3727 is intended to drive both phases of a stepper motor. Special care has been taken to provide high efficiency, robustness and to minimize external components. Power Supply The TCA 3727 will work with supply voltages ranging from 5 V to 50 V at pin Vs. As the circuit operates with chopper regulation of the current, interference generation problems can arise in some applications. Therefore the power supply should be decoupled by a 0.22 F ceramic capacitor located near the package. Unstabilized supplies may even afford higher capacities. Current Sensing The current in the windings of the stepper motor is sensed by the voltage drop across R1 and R2. Depending on the selected current internal comparators will turn off the sink transistor as soon as the voltage drop reaches certain thresholds (typical 0 V, 0.25 V, 0.5 V and 0.75 V); (R1 , R2 = 1 ). These thresholds are neither affected by variations of VL nor by variations of VS. Due to chopper control fast current rises (up to 10 A/s) will occure at the sensing resistors R1 and R2. To prevent malfunction of the current sensing mechanism R1 and R2 should be pure ohmic. The resistors should be wired to GND as directly as possible. Capacitive loads such as long cables (with high wire to wire capacity) to the motor should be avoided for the same reason. Synchronizing Several Choppers In some applications synchrone chopping of several stepper motor drivers may be desireable to reduce acoustic interference. This can be done by forcing the oscillator of the TCA 3727 by a pulse generator overdriving the oscillator loading currents (approximately 100 A). In these applications low level should be between 0 V and 1 V while high level should be between 2.6 V and VL. Optimizing Noise Immunity Unused inputs should always be wired to proper voltage levels in order to obtain highest possible noise immunity. To prevent crossconduction of the output stages the TCA 3727 uses a special break before make timing of the power transistors. This timing circuit can be triggered by short glitches (some hundred nanoseconds) at the Phase inputs causing the output stage to become high resistive during some microseconds. This will lead to a fast current decay during that time. To achieve maximum current accuracy such glitches at the Phase inputs should be avoided by proper control signals. Semiconductor Group 23 1998-12-16 TCA 3727 Thermal Shut Down To protect the circuit against thermal destruction, thermal shut down has been implemented. To provide a warning in critical applications, the current of the sensing element is wired to input Inhibit. Before thermal shut down occures Inhibit will start to pull down by some hundred microamperes. This current can be sensed to build a temperature prealarm. Semiconductor Group 24 1998-12-16 TCA 3727 Package Outlines 8 ma x 7.6 -0.2 1) +0.09 0.35 x 45 0.23 2.65 max 2.45 -0.2 0.2 -0.1 P-DSO-24-3 (Plastic Dual Small Outline Package) 0.4 +0.8 1.27 0.35 +0.15 2) 0.2 24x 24 1 0.1 10.3 0.3 13 15.6 -0.4 1) 12 Index Marking 1) Does not include plastic or metal protrusions of 0.15 max rer side 2) Does not include dambar protrusion of 0.05 max per side Sorts of Packing Package outlines for tubes, trays etc. are contained in our Data Book "Package Information". SMD = Surface Mounted Device Semiconductor Group 25 GPS05144 Dimensions in mm 1998-12-16 TCA 3727 GPD05587 P-DIP-20-6 (Plastic Dual In-line Package) Sorts of Packing Package outlines for tubes, trays etc. are contained in our Data Book "Package Information". Semiconductor Group 26 Dimensions in mm 1998-12-16