AM2916

AM2916 AMTEK | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 9

Technical content

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 1 - Dual Full-Bridge PWM Motor Driver AM2916 The AM2916 motor driver is designed to drive both windings of a bipolar stepper motor or to control bidirectionally two DC motors. Both bridges are capable of sustaining 45V and include internal pulse-width modulation (PWM) control of the output current to 750mA. The outputs have been optimized for a low output saturation voltage drop (less than 1.8V total source plus sink at 500mA). For PWM current control, the maximum output current is de termined by the user’s selection of a reference voltage and sensing resistor. Two logic-level inputs select output cu rrent limits of 0, 33%, 67%, or 100% of the maximum level. A PHASE input to each bridge determines load current direction. The bridges include both ground clamp and fly-back diodes for protection against inductive transients. Internally generated delays prevent cross-over currents when switchi ng current direction. Special power-up sequencing is not required. A thermal protection circuitry disables the outputs if the chip temperature exceeds safe operating limits. The AM2916 is supplied in a 24-lead surface-mountable SOIC. Its batwing construction provides for maximum package power dissipation in the smallest possible construc tion. Also, Pb free product is available ( Please refer to Marking Identification ). z Applications Scanner z Features 1) 750mA continuous output current 2) 45V output sustaining voltage 3) Internal clamp diodes 4) Internal PWM current control 5) Low output saturation voltage 6) Internal thermal shutdown circuitry z Absolute Maximum Ratings at TJ ≤ 150℃ Parameter Symbol Limits Unit Motor supply voltage V BB 45 V Peak +1.0 A Output current Continuous IOUT +750 mA Logic supply voltage V CC 7.0 V Logic input voltage range V IN -0.3 ~ +7.0 V Output emitter voltage V SENSE 1.5 V Operating temperature range T A -20 ~ +85 ℃ Storage temperature range T S -55 ~ +150 ℃ *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℃.

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 2 - z Thermal Data Description Symbol Value Unit Thermal Resistance Junction-case Rthjc 20 ℃/W Thermal Resistance Junction-ambient R thja 76 ℃/W *With minimized copper area. z Block Diagram VBB VCC OUT 1A OUT 2A SENSE 2 E 2 OUT 2B GROUND GROUND I 02 I 12 PHASE 2 VREF 2 RC 2 LOAD SUPPLY SENSE 1 OUT 1B I 01 GROUND GROUND I 11 PHASE 1 VREF 1 RC 1 LOGIC SUPPLY PWM1 PWM2

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 3 - z PWM Current-Control Circuitry Channel 1 terminal numbers shown OUT A +10 20KΩ 40KΩ 10KΩ VBB 17 14 OUT B 16 E SENSE RC RS CC ONE SHOT SOURCE DISABLE 9 RC 13I0 10V REF RT CT TRUTH TABLE PHASE OUT A OUT B H H L L L H

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 4 - z Electrical Characteristics ( Unless otherwise specified, Ta = 25℃, Tj ≤ 150℃, VBB = 40V , VCC = 4.75V to 5.25V , VREF = 5.0V ) Limit Unit Parameter Symbol Conditions Min Typ Max ＜Output Drivers (OUTA or OUTB)＞ Motor supply range V BB 10 - 40 V VOUT = VBB - < 1.0 50 μA Output leakage current ICEX VOUT = 0 - < -1.0 -50 μA Output sustaining voltage V CE(sus) IOUT = ±750mA, L = 3.0mH 45 - - V Sink driver, IOUT = +500mA - 0.4 0.6 V Sink driver, IOUT = +750mA - 1.0 1.2 V Source driver, IOUT = -500mA - 1.0 1.2 V Output saturation voltage V CE(SAT) Source driver, IOUT = -750mA - 1.3 1.5 V Clamp diode leakage current I R V R = 45V - < 1.0 50 μA Clamp diode forward voltage V F I F = 750mA - 1.6 2.0 V IBB(ON) Both bridges ON, no load - 20 25 mA Driver supply current IBB(OFF) Both bridges OFF - 5.0 10 mA ＜Control Logic ＞ VIN(1) All inputs 2.4 - - V Input voltage VIN(0) All inputs - - 0.8 V VIN = 2.4V - < 1.0 20 μA Input current I IN(1) VIN = 0.8V - -3.0 -200 μA Reference voltage range V REF Operating 1.5 - 7.5 V I0 = I1 = 0.8V 9.5 10 10.5 - I0 = 2.4V , I1 = 0.8V 13.5 15 16.5 - Current limit threshold (at trip point) VREF/ VSENSE I0 = 0.8V , I1 = 2.4V 25.5 30 34.5 - Thermal shutdown temperature T J - 170 - ℃ ICC(ON) I 0 = I1 = 0.8V , No load - 40 50 mA Total logic supply current ICC(OFF) I 0 = I1 = 2.4V , No load - 10 12 mA

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 5 - z Application Information

• PWM Current control The AM2916 dual bridge is designed to drive both windings of a bipolar stepper motor or to control bidirectionally two DC motors. The output current of each part is sensed and controlled independently in each bridge by external sense resistors (RS), internal comparator, and monostable multivibrator. When the bridge is turned ON, current increases in the motor winding and it is se nsed by the external sense resistor until the sense voltage (VSENSE) reaches the level set at the comparator’s input: ITRIP = VREF / 10RS The comparator then triggers the monostabel that turns O FF 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 (t d) is typically 2 µs. After turn-off, the mo tor current decays, 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 t off = RTCT within the range of 20kΩ to 100kΩ and 100pF to 1000pF. When the source driver is re-enabled, the winding curre nt (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. Loads with highly distributed capacitances may result in hi gh turn-ON current peaks. This peak (appearing across R S) will attempt to trip the comparator, resulting in err oneous current control or hi gh-frequency oscillations. An external R CCC time delay should be used to further delay the ac tion of the comparator. Depending on load type, many applications will not require these external components (SENSE connected to E). Load Current Paths VBB RS BRIDGE ON SOURCE OFF ALL OFF PWM Output Current Wave Form V PHASE I TRIP t offt d I OUT

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 6 -

• 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 (see table). The 0% output current conditio n turns OFF all drivers in the bridge and can be used as an OUTPUT DISABLE function. Current – Control Truth Table I0 I 1 Output Current L L V REF / 10RS = ITRIP H L V REF / 15RS = 2/3 ITRIP L H V REF / 30RS = 1/3 ITRIP H H 0 These logic level inputs greatly enhance the implementation of µP-controlled drive formats. During half-step operations, the I0 and I1 allow the µP to control the motor at a constant torque between all positions in an eight-step sequence. This is a accomplished by digitally selecting 100% drive current when only one phase is ON and 67% drive current when two phases are ON. Logic highs on both I 0 and I 1 turn OFF all drivers to allow rapid current decay when switching phases. This helps to ensure proper motor operation at high step rates. The logic control inputs can also be us ed 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 The PHASE input to each bridge determines the direction of current flow in the motor winding. An internally generated deadtime (approximately 2µ s) prevents crossover currents that can occur when switching the PHASE input. All four drivers in the bridge output can be turned OFF between steps (I 0 = I 1 ≧ 2.4V) resulting in a fast current decay through the inte rnal output clamp and flyback diodes. The fast current decay is desirable in half-step and high-speed applications. All inputs float high. Varying the reference voltage (V REF) provides continuous control of the p eak load current for microstepping applications and DC motor control. Thermal protection circuitry turns OFF all drivers when the junction temperature reaches +170℃. 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℃. The AM2916 output drivers are optimized for low output saturation voltages – less than 1.8V total (source plus sink) at 500mA. Under normal operating conditions, when combined with the excellent thermal properties of the batwing packing design, this allows continuous operation of both bridges simultaneously at 500mA.

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 7 - z Typical Application μP FROM VBB VBB VCC PWM1 PWM2 + 5V RC CC RS RC CC RS Stepper Motor C TR T C TR T VREF VREF μP FROM μP FROM

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 8 - z Package Outline SOP24 MILLIMETERS INCHES SYMBOL Min. Max. Min. Max. A 2.36 2.64 0.093 0.104 A1 0.10 0.30 0.004 0.012 D 15.21 15.60 0.599 0.614 E 7.39 7.59 0.291 0.299 H 10.01 10.64 0.394 0.419 L 0.41 1.27 0.016 0.050 θ° 0° 8° 0° 8°

AAMMtteekk sseemmiiccoonndduuccttoorrss NNoovv.. 22000044 VV11..44 - 9 - z Marking Identification AMtek Row II Row III Row I Row I AMtek Row II Part number (Pb) Part number L/F (Pb free) Row III Lot number