8932-A

8932-A RET REF V FLT V BEMF GROUND UV SET R OUT P OUT SWITCH IN N OUT SW RETRACT FAULT MP RESET SIGNAL SUPPLY 1 2 3 4 5 6 7 8 28 27 RET SET V SENS V LOAD V SENS FB SGND N OUTP LOAD SUPPLY OUT N SGND P ACT FB PWR OFF H GAIN REFERENCE ACT VOICE-COIL MOTOR DRIVER Providing control and drive of the voice-coil motor used for head positioning in 5 V disk drive applications, the second-generation A8932CLWA is a full-bridge driver that can be configured so that its output current is a direct function of an externally applied control voltage or current. This linear current control function is supplemented by additional circuitry to protect the heads and the data disk during system failure or normal system shutdown. The two ±500 mA MOS driver outputs provide very low saturation voltage and minimal power dissipation. Additional headroom is achieved by the sense-FET structure eliminating the need for an external current-sense resistor. Internal circuitry can be configured to provide closed-loop velocity control of the actuator by utilizing the generated back-EMF of the voice-coil motor. Thermal protection and under-voltage lockout disables the system in a controlled sequence if a fault condition occurs. Data Sheet 26300.2A† PROTECT CIRCUIT – 26 + 25 24 23 VDD 22 21 – 9 10 11 12 13 14 + V REF – 2V + 20 19 18 17 PROTECT CIRCUIT + – 16 15 V CC FEATURES I I I I I I I I I I I Class-B, 2 Ω rDS(on) at 500 mA Output Lossless Current Sensing Zero Current-Loop Deadband High Transcon...