A4936MET-T

A4936 3-Phase Brushless DC Motor Pre-Driver Features and Benefits • Drives 6 N-channel MOSFETs • Synchronous rectification for low power dissipation • Internal UVLO and thermal shutdown circuitry • Hall element inputs • PWM current limiting • Dead time protection • FG outputs • Standby mode • Lock detect protection • Overvoltage protection Description The A4936 is a complete 3-phase brushless DC motor pre-driver, supplying up to 28 V output for direct, high-current gate drive of an all N-channel power MOSFET 3-phase bridge. The device has three Hall-element inputs, a sequencer for commutation control, fixed off-time pulse width modulation (PWM) current control, and locked-rotor detection. Output current is scaled by the capability of the external MOSFETs. Locked rotor detection delay is set by an external capacitor on the CLD terminal. The PWM, DIR, and BRAKE and STOP inputs can be used to control motor speed, position, and torque. Motor speed can be determined using the FG output from an FG coil amplifier and comparator. The external MOSFETS can be PWMed using an external signal on the PWM input, or using the internal PWM current regulator. In either case, the A4936 synchronous rectification feature reduces power dissipation by turning-on the appropriate MOSFETs during current decay. The Hall elements can be inexpensive types, when used with noise filtering to prevent false commutation signals. The A4936 provides a regulated 7.5 V supply to power the three Hall elements. Package: 32-contact QFN (suffix ET) Not to scale Continued on the next page… Typical Application Diagram V+ System Control Logic BLDC Motor A4936 A4936-DS A4936 Description (continued) 3-Phase Brushless DC Motor Pre-Driver Internal circuit protection includes thermal shutdown with hysteresis, undervoltage lockout, and dead time protection. Special power-up sequencing is not required. Operating temperature range is –20°C to 105°C. The device package is a 32-contact, 5 mm × 5 mm, 0.90 mm nominal overall height QFN, with exposed pad for enhanced thermal dissipation. This small-footprint package is lead (Pb) free, with 100% matte tin leadframe plating. Selection Guide Part Number Packing* Package 32-pin QFN, 5 mm × 5 mm, 0.90 mm nominal overall height A4936MET-T 73 pieces per tube A4936METTR-T 1500 pieces per reel *Contact Allegro® for additional packing options Absolute Maximum Ratings Characteristic Load Supply Voltage Motor Phase Output Hall Input Logic Input Voltage Range Ambient Operating Temperature Maximum Junction Temperature Storage Temperature Symbol VBB Sx VHx VIN TA TJ(max) Tstg Range M tw< 500 ns DC Notes Rating 38 –3 –0.3 to 7 –0.3 to 7 –20 to 105 150 –40 to 150 Unit V V V V °C °C °C Thermal Characteristics may require derating at maximum conditions, see application information Characteristic Package Thermal Resistance (Junction to Ambient) Package Thermal Resistance (Junction to Exposed Pad) Symbol RθJA RθJP Test Conditions* On 4-layer PCB based on JEDEC standard Value 32 2 Unit ºC/W ºC/W *Additional thermal information available on the Allegro website Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 2 A4936 3-Phase Brushless DC Motor Pre-Driver Functional Block Diagram 100 nF CP1 100 nF 100 nF CLD HBIAS 2 kΩ HA+ HA– Communication Logic Control Logic Lock Detect VREG OVP Enable VREG Phase A Gate Drive VCP GHA SA GLA Charge Pump CP2 VCP VBB 100 nF 100 nF VIN Pin-out Diagram HA+ BRAKE STOP PWM DIR CLD FGS SA HALL HALL HB+ HB– HC+ HC– 32 31 30 29 28 27 26 25 HA– HB+ HB– HC+ HC– FG+ FGFB FG– 1 2 3 4 5 6 7 8 9 PAD 24 23 22 21 20 19 18 17 GHA SB GHB SC GHC GLA GLB GLC System Logic BRAKE STOP DIR PWM FGS GND 10 11 12 13 14 15 16 NC GND HBIAS CP1 CP2 VBB VCP SENSE Terminal List Table Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Name HAHB+ HBHC+ HCFG+ FGFB FGNC GND HBIAS CP1 CP2 VBB VCP SENSE GLC Hall input A Hall input B Hall input B Hall input C Hall input C FG input FG amplifier feedback output FG input No internal connection Ground Hall bias power supply output Charge pump capacitor terminal Charge pump capacitor terminal Supply voltage Reservoir capacitor terminal Sense resistor connection Low-side gate drive C Function Number 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 – Name GLB GLA GHC SC GHB SB GHA SA FGS CLD DIR PWM STOP BRAKE HA+ PAD Function Low-side gate drive B Low-side gate drive A High-side gate drive C High-side source connection C High-side gate drive B High-side source connection B High-side gate drive A High-side source connection A FG output Locked rotor detect timing capacitor Logic input: motor direction Logic input: external PWM control Logic input: output disable Logic input: motor brake Hall input A Exposed Thermal Pad – HALL + 200 mV SENSE GHB SB GLB GHC SC GLC FGFB Phase A of three phases shown – + FG– FG+ Allegro MicroSystems, Inc. 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com 3 A4936 3-Phase Brushless DC Motor Pre-Driver ELECTRICAL CHARACTERISTICS1,2 Valid at TA = 25°C, VIN = 24 V; unless otherwise noted Characteristics General Supply Voltage Range Motor Supply Current HBIAS HBIAS Current Limit Control Logic Logic Input Voltage Logic Input Current Input Pin Glitch Reject HBIAS Wake-up Delay, Standby Mode Gate Drive High-Side Gate Drive Output Low-Side Gate Drive Output Gate Drive Current (Sourcing) Gate Drive Pull-Down Resistance Dead Time Current Limit Input Threshold Fixed Off-Time Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis VBB UVLO Enable Threshold VBB UVLO Hysteresis VCP UVLO Lock Detect Duration VBB Overvoltage Threshold Hall Logic Hall Input Current Common Mode Input Range AC Input Voltage Range Hall Thresholds Hall Threshold Hysteresis Pulse Reject Filter IHALL VCMR VHALL Vth VHYS tpulse Difference between Hall inputs at transitions TJ = 25°C TJ = –20°C to 125°C VIN = 0.2 to 3.5 V –1 0.2 60 – 10 5 – 0 – – +10, –10 20 20 2 1 3.5 – – 30 40 – μA V mVp-p mV mV mV μs TJTSD TJTSDhys VBBUV VBBUVhys VCPUV tlock VBBOV Relative to VBB , VCP falling C = 0.1 μF Rising VBB Rising VBB 155 – 6.2 0.4 4.6 1.5 30 170 20 7 0.75 – 2 33 185 – 7.85 1 6 2.5 37.5 °C °C V V V s V VGS(H) VGS(L) IGATE RGATE tDEAD VREF tOFF Relative to VBB, IGATE = 2 mA IGATE = 2 mA GHx = GLx = 4 V 7 7 20 10 700 180 18 – – 30 28 1000 200 25 – – – 40 1300 220 37 V V mA Ω ns mV μs VIN(1) VIN(0) IIN(1) IIN(0) tGLITCH tdHBIAS VIN = 2 V VIN = 0.8 V PWM pin DIR, BRAKE, and STOP pins CHBIAS = 0.1 μF 2 – –1.0 –1.0 350 700 – – –