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AssigneeRohm Co., Ltd.
InventorShinichi Miura
Estimating the term…
A back electromotive force monitoring circuit has a speed detection voltage generator which biases a back electromotive force generated by a voice coil motor with a predetermined reference voltage to generate a speed detection voltage, and a calculator which generates a motor control signal in accordance with the speed detection voltage. The calculator includes a subtracter which subtracts the reference voltage from the speed detection voltage prior to generation of the motor control signal.
A back electromotive force monitoring circuit comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Synchronous motors: with four quadrant control
Driving; Starting; Stopping; Control thereof: speed controlling, regulating, or indicating
Driving or moving of heads: raising and lowering; Back-spacing or forward-spacing along track; Returning to starting position otherwise than…
Without separate position detecting elements: using back-emf in windings
About 7 years 2 months of term left · ends 11 Jan 2034 (estimated)
1. Field of the Invention
The invention described in this specification relates to an A/D [analog-to-digital] converter, an operational amplifier, or a back electromotive force monitoring circuit.
2. Description of Related Art
FIG. 1 is a block diagram showing a structural example of a motor drive device.
FIG. 2 is a block diagram showing a structural example of an A/D converter 50.
FIG. 3 is a simplified timing chart showing an example of sequential A/D conversion operation.
<Motor Drive Device>
FIG. 1 is a block diagram showing a structural example of a motor drive device. The motor drive device 1 of this structural example is a monolithic semiconductor integrated circuit device (i.e., a system motor driver IC) which performs drive control of a spindle motor 2 and a voice coil motor 3 used in a hard disk drive: has a spindle motor driver 10; a voice coil motor driver 20; an insulation switch 30; a power voltage monitor 40; A/D converter 50; a logic unit 60; a register 70; and a serial interface 80.
Besides, the motor drive device 1 has various kinds of power supply circuits (step-down / step-up / inverting switching regulators, a positive/negative output charge pump, a series regulator, etc.) to supply electric power to the inside and the outside of devices, and various kinds of sensor detection circuits to monitor an output of an external sensor (a shock sensor, a pressure sensor, a temperature sensor, and so on) except the above-mentioned structural elements. Here, the whole structure of the hard disk drive that incorporates the motor drive device I are illustrated below in detail.