US5455816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
MOS amplifier with gain control
Assignee: Taiwan Semiconductor Manufacturing Co TSMC Ltd
•
Filing: 1992-05-18
•
Granted: 1995-10-03
•
Expires: 2012-05-18
Abstract
Abstract The invention concerns differential amplifiers for computer disc drives, implemented in Metal Oxide Semiconductor (MOS) technology. The amplifiers are of the controllable-gain type. Gain is controlled by adjusting the channel current which passes through the differential Field-Effect Transistors (FETs) of the amplifier. The channel current can be viewed as having a constant component, to which is added an adjustment component. The adjustment component does not pass through the active loads of the differential amplifier, thereby allowing a larger change in gain to be attained.
Inventors
- 👤 Ricky F. Bitting
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:10
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/02; G11B5/09; H; H03; H03F; H03F3/00; H03F3/45; H03F3/45071; H03F3/45076; H03G; H03G1/00; H03G1/0005; H03G1/0017; H03G1/0029
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
31 words
In a computer disc drive, the improvement comprising: a) an MOS differential amplifier for amplifying signals received from a read/write head; and b) means for adjusting the gain of said amplifier.
Claim 2
Dependent Claim
31 words
In a computer disc drive, the improvement comprising: a) an MOS differential amplifier for amplifying signals received from a read/write head; and b) means for adjusting the gain of said amplifier.
Claim 3
Dependent Claim
22 words
Apparatus according to claim 1, in which the bandwidth remains substantially constant as voltage gain is varied between 5 and 15 dB.
Claim 4
Dependent Claim
34 words
A computer disc drive, comprising: a) an MOS differential amplifier, comprising differential FETs, for amplifying signals produced by a read/write head; b) an auxiliary current source for providing additional currents to the differential FETs.
Claim 5
Dependent Claim
34 words
A computer disc drive, comprising: a) an MOS differential amplifier, comprising differential FETs, for amplifying signals produced by a read/write head; b) an auxiliary current source for providing additional currents to the differential FETs.
Claim 6
Dependent Claim
57 words
A computer disc drive, comprising: a) an MOS differential amplifier, comprising differential FETs and load devices, for amplifying signals produced by a read/write head; b) an auxiliary current source for providing additional currents to the differential FETs; and c) bypass means for allowing the additional currents to reach the differential FETs without passing through the load devices.
Claim 7
Dependent Claim
57 words
A computer disc drive, comprising: a) an MOS differential amplifier, comprising differential FETs and load devices, for amplifying signals produced by a read/write head; b) an auxiliary current source for providing additional currents to the differential FETs; and c) bypass means for allowing the additional currents to reach the differential FETs without passing through the load devices.
Claim 8
Dependent Claim
66 words
In a computer disc drive, the improvement comprising: a) an MOS differential amplifier, including i) differential FETs, ii) a load for each differential FET, each load passing a load current, and iii) a first common current-source for supplying a current which is shared by the differential FETs; and b) a second common current source for supplying a second current which is shared by the differential FETs.
Claim 9
Dependent Claim
66 words
In a computer disc drive, the improvement comprising: a) an MOS differential amplifier, including i) differential FETs, ii) a load for each differential FET, each load passing a load current, and iii) a first common current-source for supplying a current which is shared by the differential FETs; and b) a second common current source for supplying a second current which is shared by the differential FETs.
Claim 10
Dependent Claim
18 words
Apparatus according to claim 5 and further comprising means for shunting load currents away from the differential FETs.
Claim 11
Dependent Claim
52 words
A computer disc drive, comprising: a) an MOS differential amplifier having i) two differential FETs and ii) an active load for each said FET; and b) a shunt FET for increasing the current passing through an active load, without increasing the current passing through the differential FET loaded by said active load.
Claim 12
Dependent Claim
52 words
A computer disc drive, comprising: a) an MOS differential amplifier having i) two differential FETs and ii) an active load for each said FET; and b) a shunt FET for increasing the current passing through an active load, without increasing the current passing through the differential FET loaded by said active load.
Claim 13
Dependent Claim
88 words
In a computer disc drive, an amplifier for amplifying signals received from a read/write head, comprising: a) active load FETs (MP1, MP2); b) differential FETs (MN1 and MN2), for driving the active load FETs; c) a substantially constant current source (MN5), for providing current to the differential FETs; d) a controllable, auxiliary current source (MN6), for providing additional current to the differential FETs; and e) bypass means (MP3, MP4) for allowing the additional current to reach the differential FETs (MN1, MN2) without passing through the active load FETs.
Claim 14
Dependent Claim
88 words
In a computer disc drive, an amplifier for amplifying signals received from a read/write head, comprising: a) active load FETs (MP1, MP2); b) differential FETs (MN1 and MN2), for driving the active load FETs; c) a substantially constant current source (MN5), for providing current to the differential FETs; d) a controllable, auxiliary current source (MN6), for providing additional current to the differential FETs; and e) bypass means (MP3, MP4) for allowing the additional current to reach the differential FETs (MN1, MN2) without passing through the active load FETs.
Claim 15
Dependent Claim
32 words
In a computer disc drive, the improvement comprising: a) an MOS amplifier, which i) receives signals from a read/write head, and ii) has a 3-dB rolloff point at or above 30 MegaHertz.
Claim 16
Dependent Claim
32 words
In a computer disc drive, the improvement comprising: a) an MOS amplifier, which i) receives signals from a read/write head, and ii) has a 3-dB rolloff point at or above 30 MegaHertz.
Claim 17
Dependent Claim
17 words
Apparatus according to claim 9, and further comprising means for adjusting the gain of the MOS amplifier.
Claim 18
Dependent Claim
25 words
Apparatus according to claim 10, in which the MOS amplifier is capable of providing a voltage gain of 15 dB at said 3-dB rolloff point.
Claim 19
Dependent Claim
25 words
Apparatus according to claim 10, in which the MOS amplifier is capable of providing a voltage gain of 10 dB at said 3-dB rolloff point.
Claim 20
Dependent Claim
25 words
Apparatus according to claim 10, in which the MOS amplifier is capable of providing a voltage gain of 5 dB at said 3-dB rolloff point.
References Cited (Backward Citations)
US4184124A
Cited
US4459555A
Cited
US4578723A
Cited
US4622599A
Cited
US4712144A
Cited
US4772964A
Cited
US4667165A
Cited
US4849834A
Cited
US4766394A
Cited
US4849711A
Cited
US4777472A
Cited
US5051847A
Cited
US4973915A
Cited
US5184090A
Cited
US5168395A
Cited
US5124849A
Cited
US5132852A
Cited
US5257146A
Cited
US5319508A
Cited
US5327297A
Cited
US5142238A
Cited
US5280196A
Cited
US5270882A
Cited
US5309298A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-02 | 1999-04-03 | 1999-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-02 | 2003-04-03 | 2003-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-02 | 2007-04-03 | 2007-10-03 | $7700.00 | Window Closed / Lapsed |