description the A4937 is a 3-phase controller for use with n-channel external power mosfets and is specifically designed for automotive applications. a unique charge pump regulator provides full (>10 v) gate drive for battery voltages down to 7 v and allows the A4937 to operate with a reduced gate drive, down to 5.5 v. a bootstrap capacitor is used to provide the above battery supply voltage required for n-channel mosfets. full control over all six power mosfets in the 3-phase bridge is provided, through an spi compatible serial interface, allowing motors to be driven with block or overlap commutation. power output can be regulated by one or both of the pwm inputs. the power mosfets are protected from shoot-through by integrated crossover control and programmable dead time. integrated diagnostics provide indication of undervoltage, overtemperature, and power bridge faults, and can be configured to protect the power mosfets under most short circuit conditions. detailed diagnostics are available as a serial data word. the A4937 is supplied in a 28-pin tssop power package with with exposed pad for enhanced thermal dissipation (package type lp). this package is lead (pb) free, with 100% matte-tin leadframe plating. A4937a-ds features and benefits ? high current 3-phase gate drive for n-channel mosfets ? spi compatible serial control ? cross-conduction protection ? programmable dead time ? 5.5 to 50 v supply voltage range ? ttl inputs compatible with 3.3 v and 5 v logic ? extensive diagnostics output ? low current sleep mode applications automotive 3-phase mosfet driver package: 28-pin tssop with exposed thermal pad (suffix lp) functional block diagram not to scale A4937 3-phase bldc motor A4937 v bat spi a8450 regulator micro- controller v bat pwm reset diagnostics ? electronic power steering (eps, ehps, eas) ? hydraulic pumps ? gearbox actuator
automotive 3-phase mosfet driver A4937 2 allegro microsystems, llc 115 northeast cutoff worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com absolute maximum ratings* characteristic symbol notes rating unit load supply voltage v bb ?0.3 to 50 v logic supply voltage v dd ?0.3 to 6 v terminal vreg v reg ?0.3 to 16 v terminal cp1 v cp1 ?0.3 to 16 v terminal cp2 v cp2 v cp1 ? 0.3 to v reg + 0.3 v logic inputs v i strn, sck, sdi, pwmh, pwml ?0.3 to 6 v resetn; can be pulled to v bb with >22 k
automotive 3-phase mosfet driver A4937 worcester, massachusetts 01615-0036 u.s.a. 1.508.853.5000; www.allegromicro.com functional block diagram charge pump regulator vbat cp2cp1 diag lss gla gha sa ca vreg battery + vreg phase a vbb pwml phase c phase b c boota c reg c p pwmh vbrg bootstrap monitor vds monitor vds monitor gnd strn sck sdi sdo vdd control logic diagnostics and protection serial interface resetn one of three phases shown r gate r gate high side drive low side drive allegro microsystems, llc 3 115 northeast cutoff
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