A3930 and A3931: Automotive 3-Phase BLDC Controller and MOSFET Driver
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A3930 and A3931 Description The A3930 and A3931 are 3-phase brushless DC (BLDC) motor controllers for use with N-channel external power MOSFETs. They incorporate much of the circuitry required to design a cost effective three-phase motor drive system, and have been specifically designed for automotive applications. A key automotive requirement is functionality over a wide input supply range. A unique charge pump regulator provides adequate (>10 V) gate drive for battery voltages down to 7 V, and allows the device to operate with a reduced gate drive at battery voltages down to 5.5 V. Power dissipation in the charge pump is minimized by switching from a voltage doubling mode at low supply voltage to a dropout mode at the nominal running voltage of 14 V. A bootstrap capacitor is used to provide the above-battery supply voltage required for N-channel MOSFETs. An internal charge pump for the high-side drive allows for DC (100% duty cycle) operation. Internal fixed-frequency PWM current control circuitry can be used to regulate the maximum load current. The peak load current limit is set by the selection of an input reference voltage and external sensing resistor. The PWM frequency is set by a user-selected external RC timing network. For added flexibility, the PWM input can be used to provide speed and 3930-DS Rev. 4 Features and Benefits High current 3-phase gate drive for N-channel MOSFETs Synchronous rectification Cross-conduction protection Charge pump and top-off charge pump for 100% PWM Integrated commutation decoder logic Operation over 5.5 to 50 V supply voltage range Extensive diagnostics output Provides +5 V Hall sensor power Low-current sleep mode Automotive 3-Phase BLDC Controller and MOSFET Driver Typical Application Continued on the next page… Package: 48 Lead LQFP with exposed thermal pad (suffix JP) Approximate Scale 1:1

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 2 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com torque control, allowing the internal current control circuit to set the maximum current limit. Efficiency is enhanced by using synchronous rectification. The power FETs are protected from shoot-through by integrated crossover control with dead time. The dead time can be set by a single external resistor. The A3930 and A3931 only differ in their response to the all-zero combination on the Hall...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 3 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com P High-Side Drive Low-Side Drive Blanking Charge Pump Regulator Charge Pump Boostrap Monitor +5V Ref OSC R S Q Diagnostics and Protection –UVLO –TSD –Short to Supply –Short to Ground –Shorted Winding –Low Load P RSENSE H1 H2 H3 V5 V5BD CA SA TACHO VBB RC RT CT RDEAD VDRAIN Phase A of three phases VDSTH REF CSOUT Control Logic LSS AGND CSN Pad CSP RESET TEST FF1 PWM FF2 GHA H1 V5 H2 H3 DIR DIRO...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 4 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com ELECTRICAL CHARACTERISTICS at TJ = –40°C to 150°C, VBB = 7 to 45 V, unless otherwise noted1 Characteristics Symbol Test Conditions Min. Typ. Max. Units Supply and Reference VBB Functional Operating Range6 VBB Function correct, parameters not guaranteed 5.5 – 50 V VBB Quiescent Current IBBQ RESET = High, outputs = Low – 11 14 mA IBBS RESET = Low, sleep mode – – 10 ìA V5 Quiescent Current IV5Q...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 5 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com Continued on the next page… Turn-Off Propagation Delay tp(off) From Hall input change to unloaded gate output change 300 500 700 ns From other control input change to unloaded gate output change – 150 200 ns Dead Time (turn-off to turn-on delay) tDEAD RDEAD = 5 kÙƒn – 180 – ns RDEAD = 50 kÙ 835 960 1090 ns RDEAD = 400 kÙ – 3.3 – ìs RDEAD = tied to V5 – 6 – ìs Logic Inputs and Outputs FFx Fault...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 6 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com Supply Rejection PSRR CSP = CSN = AGND, 0 to 300 kHz – 45 – dB Small Signal 3 dB Bandwidth Frequency f3dB VID=10 mVPP – 1.6 – MHz Settling Time tSETTLE To within 10%, VCSOUT = 1 VPP square wave – 400 – ns AC Common Mode Gain ACMac VICR= 250 mVPP, 0 to 1 MHz – –28 – dB Common Mode Recovery Time tCMrec To within 100 mV, VICR= +4.1 to 0 V step – 1 – ìs Output Slew Rate SR 10% to 90% points, VID= 0...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 7 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com Thermal Characteristics Power Dissipation versus Ambient Temperature THERMAL CHARACTERISTICS may require derating at maximum conditions, see Applications Information section Characteristic Symbol Test Conditions* Value Units Package Thermal Resistance RèJA 4-layer PCB, based on JEDEC standard 23 ºC/W 2-layer PCB, with 3 in.2 of copper area each side connected by thermal vias 44 ºC/W...

Automotive 3-Phase BLDC Controller and MOSFET Driver A3930 and A3931 Allegro MicroSystems, Inc. 8 115 Northeast Cutoff Worcester, Massachusetts 01615-0036 U.S.A. 1.508.853.5000; www.allegromicro.com Basic Operation The A3930 and A3931 devices provide commutation and current control for 3-phase brushless DC (BLDC) motors with integrated Hall-effect (HE) sensors. The motor current is provided by an external 3-phase N-channel MOSFET bridge which is controlled by the A3930/A3931, using fixed-frequency pulse width modulation (PWM). The use of PWM with N-channel MOSFETs provides the most...