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US 2013/0278199 A1Published application
Integration of spindle external sense resistor into servo ic with stable resistance control circuit
AssigneeTexas Instruments Incorporated
InventorsDaijiro Otani, Nakoyuki Tsuruoka, Masaki Yamashita
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Abstract
An apparatus, comprises three driver FETs coupled at their sources; note-driver circuit; a first sense FET coupled to the sources of the three driver FETs; a current mirror having the first sense FET and a mirror FET; wherein the first sense FET is coupled to the mirror FET; a first transconductance amplifier coupled to the first sense FET; a second amplifier coupled to the current mirror, and an output of the first transconductance amplifier is an input to the second amplifier.
Claims18
An apparatus, comprising:
- three driver FETs coupled at their sources;
- a first sense FET coupled to the sources of the three driver FETs;
- a current mirror having the first sense FET and a mirror FET;
- wherein the first sense FET is coupled to the mirror FET;
- a first transconductance amplifier coupled to the first sense FET;
- a second amplifier coupled to the current mirror;
- and
- an output of the first transconductance amplifier is an input to the second amplifier.
5 more elements
An apparatus, comprising:
- a waveshaper that generates a pulse width modulated signal;
- a programmable gain (Cg), coupled to the waveshaper
- three driver FETs coupled at their sources that are drive by the pulse width modulated signal;
- a first sense FET coupled to the sources of the three driver FETs;
- a current mirror having the first sense FET and a mirror FET;
- wherein the first sense FET is coupled to the mirror FET;
- a first transconductance amplifier coupled to the first sense FET;
- a second amplifier coupled to the current mirror, and
- an output of the first transconductance amplifier is an input to the second amplifier
- wherein the overall system gain consistent when the gain of the programmable gain (Cg) and a gain of the selectable sense transistor are changed at substantially the same time.
7 more elements
An apparatus, comprising:
- a waveshaper that generates a pulse width modulated signal;
- a programmable gain (Cg), coupled to the waveshaper
- three driver FETs coupled at their sources that are drive by the pulse width modulated signal;
- a first sense FET coupled to the sources of the three driver FETs;
- a current mirror having the first sense FET and a mirror FET;
- wherein the first sense FET is coupled to the mirror FET;
- a first transconductance amplifier coupled to the first sense FET;
- a second amplifier coupled to the current mirror,
- an output of the first transconductance amplifier is an input to the second amplifier;
- a feedback loop between the sense transistor and a reference resistor coupled to a second input of the second amplifier;
- and
- wherein the overall system gain consistent when the gain of the programmable gain (Cg) and a gain of the selectable sense transistor are changed at substantially the same time.
9 more elements
Dependencies are inferred from the claim text.