公开(公告)号：EP1759383A4

公开(公告)日：2015-06-10

申请号：EP05753030

申请日：2005-05-23

申请人： TEXAS INSTRUMENTS INC

发明人： EL-SHERIF ALAA Y ,  PLUTOWSKI EUGENE F ,  ZIEMER KEVIN W

IPC分类号： G11B5/596 ,  G11B5/55 ,  H02M7/527 ,  H02M7/5395 ,  H02P25/02 ,  H02P27/08

CPC分类号： G11B5/556 ,  G11B5/022 ,  H02M7/5395 ,  H02M2001/0022 ,  H02M2001/0025 ,  H02P25/034 ,  H02P27/085 ,  H02P31/00 ,  H02P2209/09

摘要： A positioning driver ( 32 ) for a voice coil motor ( 22 ) in a disk drive system ( 10 ) is disclosed. Pulse-width-modulated prestage drivers ( 46 ) are coupled to power transistors ( 50 ) arranged in an "H" bridge for driving the voice coil motor ( 22 ), biased with a power supply voltage (V M ). The pulse-width-modulated prestage drivers ( 46 ) drive the power transistors ( 50 ) according to a comparison between an error signal from an error amplifier ( 36 ) and a ramp clock signal (RMP) generated by a ramp clock generator ( 46 ). The ramp clock generator ( 46 ) includes a control circuit ( 68 ) that modulates the high and low limits of the ramp clock signal (RMP) in response to variations in the power supply voltage (V M ). This modulation of the high and low limits compensates for variations in the gain of the power transistors ( 50 ) resulting from variations in the power supply voltage (V M ). The control circuit ( 68 ) may also modulate the slope of the ramp clock signal (RMP) according to variations in the power supply voltage (V M ), for example to maintain a constant frequency.

公开(公告)号：EP1774518A4

公开(公告)日：2008-09-17

申请号：EP05762226

申请日：2005-05-23

申请人： TEXAS INSTRUMENTS INC

发明人： ZIEMER KEVIN W ,  EL-SHERIF ALAA Y ,  PLUTOWSKI GENE

IPC分类号： G11B5/596 ,  G11B5/55

CPC分类号： G11B5/5547 ,  G11B5/022 ,  G11B5/59605

摘要： A dual-mode positioning driver for a voice coil motor (22) in a disk drive system is disclosed. Linear prestage drivers and pulse-width-modulated prestage drivers (46) are both coupled to power transistors (50PH, 50NH, 50PL, 50NL) arranged in an 'H' bridge for driving the voice coil motor (22). The positioning driver is thus operable to drive the power transistors (50) in either a linear mode or a pulse-width-modulated class D mode. In a transition period, while switching from the pulse-width-modulated mode to linear mode, comparators (56H, 56L) compare the phase voltages in the 'H' bridge with a reference voltage. The outputs of the comparators (56H, 56L) are applied to the PWM output amplifiers (54H, 54L) to drive the power transistors (50), so that the phase voltages are preconditioned toward their linear bias points. Discontinuities in the drive current through the voice coil motor (22) are minimized as a result.