Dual Full Bridge PWM Motor Driver

EN1 om .c 4U et he aS at .D w w w SENSE 1 PHASE 1 VREF 1 ENABLE 1 2 91 7 DUAL FULL-BRIDGE PWM MOTOR DRIVER The UDN2917EB motor driver is designed to drive both windings of a bipolar stepper motor or bidirectionally control two dc motors. Both bridges are capable of sustaining 45 V and include internal pulse-width modulation (PWM) control of the output current to 1.5 A. For PWM current control, the maximum output current is determined by the user’s selection of a reference voltage and sensing resistor. Two logic-level inputs select output current limits of 0, 33%, 67%, or 100% of the maximum level. A PHASE input to each bridge determines load current direction. Active-low ENABLE inputs control the four drivers in each bridge. The bridges include both ground clamp and flyback diodes for protection against inductive transients. Internally generated delays prevent cross-over currents when switching current direction. Special power-up sequencing is not required. Thermal protection circuitry disables the outputs if the chip temperature exceeds safe operating limits. The UDN2917EB is supplied in a 44-lead power PLCC for surfacemount applications. Its batwing construction provides for maximum package power dissipation in the smallest possible construction. The UDN2917EB is provided for operation over an ambient temperature range of -20°C to +85°C. Data Sheet 29319.22A GND 7 8 9 10 11 12 13 14 15 16 2 1 GND 17 ABSOLUTE MAXIMUM RATINGS at TJ ≤ +150°C Motor Supply Voltage, VBB .................... 45 V Output Current, IOUT (tw ≤ 20 µs) ..... ±1.75 A (Continuous) ............................... ±1.5 A Logic Supply Voltage, VCC .................... 7.0 V Logic Input Voltage Range, VIN ................................ -0.3 V to +7.0 V Output Emitter Voltage, VE ................... 1.0 V Package Power Dissipation, PD ......................................... See Graph Operating Temperature Range, TA .................................. -20°C to +85°C Storage Temperature Range, TS ................................ -55°C to +150°C Output current rating may be limited by duty cycle, ambient temperature, and heat sinking. Under any set of conditions, do not exceed the specified peak current rating or a junction temperature of +150°C. m o .c U t4 e e h S ta a .D w w w θ 1 43 42 41 44 VCC 40 2 1 39 38 37 36 35 34 33 32 31 GND PWM 1 PWM 2 30 29 GND 6 5 4 3 VBB θ2 ENABLE 2 27 PHASE 2 26 EN 2 RC1 E1 LOAD SUPPLY 22 OUT 2B 21 OUT 2A 18 SENSE 2 20 V REF 2 25 RC 2 28 E2 19 I20 23 I21 24 LOGIC SUPPLY OUT 1A OUT 1B I10 I11 Dwg. PP-021 Dwg. PP-021 FEATURES s 1.5 A Continuous Output Current s 45 V Output Sustaining Voltage s Internal Clamp Diodes s Digital Control of Output Current om .c 4U et he aS at Always order by complete part number: UDN2917EB . .D w w w s Internal Thermal Shutdown Circuitry s Similar to Dual PBL3770 2917 DUAL FULL-BRIDGE PWM MOTOR DRIVER PWM CURRENT-CONTROL CIRCUITRY CHANNEL 1 PIN NUMBERS SHOWN. VBB 22 OUT B 6 3 OUT A V REF 44 20 kΩ ÷10 40 kΩ 10 kΩ I0 2 I1 1 R S 5 E SENSE – 4 + ONE SHOT 41 RC SOURCE DISABLE RC C C R T C T Dwg. EP-007-2A ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS TRUTH TABLE 12.5 Enable R θJ Phase H L X OutA H L Z OutB L H Z 10 L L H X = Don’t care Z = High impedance T /W °C =6 7.5 5.0 2.5 R θJA = 3 0° C/W 0 25 50 75 100 TEMPERATURE IN °C 125 150 Dwg. GP-020B 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright © 1991, 2001 Allegro MicroSystems, Inc. 2917 DUAL FULL-BRIDGE PWM MOTOR DRIVER ELECTRICAL CHARACTERISTICS at TA = +25°C, VBB = 45 V, VCC = 5.0 V, VREF = 5.0 V (unless otherwise noted). Limits Characteristic Output Drivers (OUTA or OUTB) Motor Supply Range Output Leakage Current VBB ICEX VOUT = VBB VOUT = 0 Output Sustaining Voltage Output Saturation Voltage VCE(sus) VCE(SAT) IOUT = ±1.5 A, L = 3.5 mH Sink Driver, IOUT = +1.0 A* Sink Driver, IOUT = +1.5 A* Source Driver, IOUT = -1.0 A* Source Driver, IOUT = -1.5 A* Clamp Diode Leakage Current Clamp Diode Forward Voltage Driver Supply Current IR VF IBB(ON) IBB(OFF) Control Logic Input Voltage VIN(1) VIN(0) Input Current IIN(1) IIN(0) Reference Voltage Range Current Limit Threshold (at trip point) VREF VREF /VSENSE All Inputs All Inputs VIN = 2.4 V VIN = 0.8 V Operating I0 = I1 = 0.8 V I0 = 2.4 V, I1= 0.8 V I0 = 0.8 V, I1 = 2.4 V Thermal Shutdown Temp. Total Logic Supply Current TJ ICC(ON) ICC(OFF) I0 = I1 = VEN = 0.8 V, No Load I0 = I1 = 2.4 V, No Load 2.4 — — — 1.5 9.5 13.5 25.5 — — — — — <1.0 -3.0 — 10 15 30 170 90 10 — 0.8 20 -200 7.5 10.5 16.5 34.5 — 105 12 V V µA µA V — — — °C mA mA VR = 45 V IF = 1.5 A Both Bridges On, No Load Both Bridges Off 10 — — 45 — — — — — — — — — <1.0 <-1.0 — 0.5 0.8 1.8 1.9 <1.0 1.6 9.0 4.0 45 50 -50 — 0.7 1.0 1.9 2.1 50 2.0 12 6.0 V µA µA V V V V V µA V mA mA Symbol Test Conditions Min. Typ. Max. Units Negative current is defined as coming out of (sourcing) the specified device pin. Typical Data is for design information only. * Pulse test (<10 ms). www.allegromicro.com 2917 DUAL FULL-BRIDGE PWM MOTOR DRIVER APPLICATIONS INFORMATION PWM CURRENT CONTROL The UDN2917EB dual bridge is designed to drive both windings of a bipolar stepper motor. Output current is sensed and controlled independently in each bridge by an external sense resistor (RS), internal comparator, and monostable multivibrator. When the bridge is turned on, current increases in the motor winding and it is sensed by the external sense resistor until the sense voltage (VSENSE) reaches the level set at the comparator’s input: ITRIP = VREF /10 RS The comparator then triggers the monostable which turns off the source driver of the bridge. The actual load current peak will be slightly higher than the trip point (especially for low-inductance loads) because of the internal logic and switching delays. This delay (td) is typically 2 µs. After turn-off, the motor current will normally decay, circulating through the ground clamp diode and sink transistor. The source driver’s off time (and therefore the magnitude of the current decrease) is determined by the monostable’s external RC timing components, where toff = RTCT within the range of 20 kΩ to 100 kΩ and 200 pF to 500 pF. When the source driver is re-enabled, the winding current (the sense voltage) is again allowed to rise to the comparator’s threshold. This cycle repeats itself, maintaining the average motor winding current at the desired level. Special circuitry has been included to prevent runaway current control when the fixed off time (toff) is set too short. This circuitry prevents the source driver from being re-enabled until the load current has decayed to below the ITRIP level. RS td t off Dwg. WM-003-1A PWM OUTPUT CURRENT WAVEFORM V PHASE + I OUT 0 – I TRIP LOAD CURRENT PATHS V BB BRIDGE ON SOURCE OFF ALL OFF Dwg. EP-006-1 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 2917 DUAL FULL-BRIDGE PWM MOTOR DRIVER CURRENT-CONTROL TRUTH TABLE I0 L H L H I1 L L H H Output Current VREF /10 RS = ITRIP VREF /15 RS = 2/3 ITRIP VREF /30 RS = 1/3 ITRIP 0 Loads with high distributed capacitances may result in high turn-on current peaks. This peak (appearing across RS) will attempt to trip the comparator, resulting in erroneous current control or high-frequency oscillations. An external RCCC low-pass filter may be needed to delay the action of the comparator. LOGIC CONTROL OF OUTPUT CURRENT Two logic level inputs (I0 and I1) allow digital selection of the motor winding current at 100%, 67%, 33%, or 0% of the maximum level per the table. The 0% output current condition turns off all drivers in the bridge and can be used as an output enable function. These logic level inputs greatly enhance the implementation of µP-controlled drive formats. During half-step operations, the I0 and I1 inputs allow the µP to control the motor at a constant torque between all positions in an eightstep sequence. This is accomplished by digitally selecting 100% drive current when only one phase is on and 67% drive current when two phases are on. The logic control inputs can also be used to select a reduced current level (and reduced power dissipation) for ‘hold’ conditions and/or increased current (and available torque) for start-up conditions. GENERAL To avoid excessive voltage spikes on the LOAD SUPPLY pin (VBB), a large-value capacitor (≥47 µF) should be connected from VBB to ground as close as possible to the device. Under no circumstances should the voltage at LOAD SUPPLY exceed 45 V. The PHASE input to each bridge determines the direction motor winding current flows. An internally generated deadtime (approximately 3 µs) prevents crossover currents that can occur when switching the PHASE input. All four drivers in the bridge output can be turned off (VEN ≥ 2.4 V or I0 = I1 ≥ 2.4 V), resulting in a fast current decay through the internal output clamp and flyback diodes. The fast current decay is desirable in half-step and high-speed applications. All logic inputs float high; the ENABLE input must be tied low if it is not used. Varying the reference voltage (VREF) provides continuous control of the peak load current for micro-stepping applications, within the specified limits for VREF. Thermal protection circuitry turns off all drivers when the junction temperature reaches +170°C. It is only intended to protect the device from failures due to excessive junction temperature and should not imply that output short circuits are permitted. The output drivers are re-enabled when the junction temperature cools to +145°C. www.allegromicro.com 2917 DUAL FULL-BRIDGE PWM MOTOR DRIVER UDN2917EB Dimensions in Inches (controlling dimensions) 28 18 29 0.319 0.291 0.021 0.013 0.695 0.685 0.656 0.650 0.319 0.291 0.050 BSC INDEX AREA 17 0.032 0.026 39 7 40 0.020