Abstract: A quiet motor control system is described. This system digitally determines modulated voltages applied to motor phases in a manner that compensates for winding torque distortions, which reduces acoustic emissions.

Abstract: A quiet motor control system is described. This system digitally determines modulated voltages applied to motor phases in a manner that compensates for winding torque distortions, which reduces acoustic emissions.

Abstract: A retract circuit (40) for retracting a data transducer carriage assembly (17) of a mass data storage device (10) to a retracted position has a digital state machine (55) that is user programmable to operate in a selected retract mode. An analog control circuit (44) is provided for receiving control signals from the digital state machine (55) for providing analog retract signals to move the data transducer carriage assembly (70). The digital state machine (55) is user programmable to operate in constant voltage, velocity detect, float and pulse, and crash stop detect modes. Preferably, the digital state machine (55) is programmed to detect a velocity of the data transducer carriage assembly (17). The digital state machine (55) also is preferably programmed to detect an error velocity of the data transducer carriage assembly (17) from a difference of a measured voltage across the data transducer driver (22) from a predetermined voltage.

Abstract: A hard disk drive energy recovery circuit, a method of recovering energy from a motor of a hard disk drive and a hard disk drive. In one embodiment, the hard disk drive energy recovery circuit includes (1) a spindle resolver that generates transition signals as a spindle motor of the hard disk drive rotates among angular regions, (2) a spindle region state machine, coupled to the spindle resolver, that receives the transition signals and generates rectifier drive signals based thereon and (3) a synchronous rectifier, coupled to the spindle region state machine, that employs the rectifier drive signals to recover electrical energy from the motor.

Abstract: A transconductance circuit (16) and method for protecting an H-bridge power circuit (10) that provides power to a load that includes an inductive component (14) connected between one side of the inductive component (14) and a gate (25) of a low side transistor (24) of the H-bridge (10). The transconductance circuit (16) operates to pull current from the inductive component (14) to ground (30) when the inductive load (14) sources current to a body diode of the high side transistor (20). The transconductance circuit (16) creates a regulated voltage to the gate (25) of the low side transistor (24) to cause the low side transistor (24) to conduct the current away in a regulated manner from the inductor (14) and the high side transistor (20) to ground (30).

Abstract: A retract circuit (40) for retracting a data transducer carriage assembly (17) of a mass data storage device (10) to a retracted position has a digital state machine (55) that is user programmable to operate in a selected retract mode. An analog control circuit (44) is provided for receiving control signals from the digital state machine (55) for providing analog retract signals to move the data transducer carriage assembly (70). The digital state machine (55) is user programmable to operate in constant voltage, velocity detect, float and pulse, and crash stop detect modes. Preferably, the digital state machine (55) is programmed to detect a velocity of the data transducer carriage assembly (17). The digital state machine (55) also is preferably programmed to detect an error velocity of the data transducer carriage assembly (17) from a difference of a measured voltage across the data transducer driver (22) from a predetermined voltage.

Abstract: In a method and circuit for retracting a data transducer carrying assembly (17) in a mass data storage device (10), has the assembly (17) is positioned in response to a voltage applied to a driver mechanism (22), and a crash-stop barrier (21) against which the assembly (17) contacts when the assembly (17) is moved to the retract position (23). When a retract process is initiated, a determination is made whether the assembly (17) has contacted the crash-stop barrier (21). If the determination establishes that the assembly (17) has contacted the crash-stop barrier (21), the retract process is terminated. Determining whether the assembly (17) has contacted the crash-stop barrier (21) may be performed, for example, by determining an instantaneous direction of movement of the assembly (17), which may be determined by determining a sign change in the velocity measurements of the assembly (17).

Abstract: In a method and circuit for retracting a data transducer carrying assembly (17) in a mass data storage device (10), has the assembly (17) is positioned in response to a voltage applied to a driver mechanism (22), and a crash-stop barrier (21) against which the assembly (17) contacts when the assembly (17) is moved to the retract position (23). When a retract process is initiated, a determination is made whether the assembly (17) has contacted the crash-stop barrier (21). If the determination establishes that the assembly (17) has contacted the crash-stop barrier (21), the retract process is terminated. Determining whether the assembly (17) has contacted the crash-stop barrier (21) may be performed, for example, by determining an instantaneous direction of movement of the assembly (17), which may be determined by determining a sign change in the velocity measurements of the assembly (17).

Abstract: A transconductance circuit (16) and method for protecting an H-bridge power circuit (10) that provides power to a load that includes an inductive component (14) connected between one side of the inductive component (14) and a gate (25) of a low side transistor (24) of the H-bridge (10). The transconductance circuit (16) operates to pull current from the inductive component (14) to ground (30) when the inductive load (14) sources current to a body diode of the high side transistor (20). The transconductance circuit (16) creates a regulated voltage to the gate (25) of the low side transistor (24) to cause the low side transistor (24) to conduct the current away in a regulated manner from the inductor (14) and the high side transistor (20) to ground (30).