Jeremy Robert Kuehlwein

6580315, Jun 17, 2003

Apr 4, 2002

10/115654

Jeremy R. Kuehlwein - Woodbury MN

Texas Instruments Incorporated - Dallas TX

H03F 102

330 9, 330 11, 330 51, 327307

A low-power solution for maintaining an amplifier common-mode output voltage, regardless of whether the amplifier is on or off, that does not degrade the performance of the amplifier through the use of a passgate in the signal path.

6696896, Feb 24, 2004

Aug 8, 2001

09/924884

Jeremy Kuehlwein - Woodbury MN
Craig M. Brannon - Maplewood MN

Texas Instruments Incorporated - Dallas TX

H03F 304

330305, 330292, 327359, 360 46

A pole and zero circuit for changing the position of a pole, or a zero, of an amplifier including a capacitor to change the position of the pole or zero for the amplifier, a first current path for the capacitor, a variable impedance device in the first current path to connect the capacitor to the amplifier, and a current source to control the impedance of the variable impedance device.

7023647, Apr 4, 2006

Nov 17, 2003

10/715217

Bryan E. Bloodworth - Irving TX, US
Congzhong Huang - Plano TX, US
Michael Sheperek - Longmont CO, US
Jeremy R. Kuehlwein - Woodbury MN, US

Texas Instruments Incorporated - Dallas TX

G11B 21/02

360 75

A fly height controller (FHC; FHC′) for controlling the fly height of a read/write head assembly () in a disk drive () is disclosed. A heat element resistor () is disposed within the read/write head assembly (). The fly height controller (FHC; FHC′) includes registers (R, W) for storing digital data words corresponding to the desired drive levels to be applied to the heat element resistor () during read and write operations. The registers (R, W) are selectively coupled to a steady-state digital-to-analog converter (DAC) (), depending upon whether a read or write operation is occurring; the output of the steady-state DAC () is applied to a voltage driver (), which in turn drives current into the heat element resistor (). Overdrive and underdrive transistors (P, N) are provided to overdrive and underdrive the input to the voltage driver () in transitions between read and write operations. An initial state register () receives a digital word indicating the desired current for the heat element resistor () when unselected; the output of the initial state register () is applied to an initial state DAC (), which drives an initial state voltage driver ().

7068454, Jun 27, 2006

Dec 30, 2003

10/749088

Jeremy Kuehlwein - Woodbury MN, US
Scott Sorenson - Lakeville MN, US

Texas Instruments Incorporated - Dallas TX

G11B 5/02

360 67, 360 46

A write driver produces balanced voltages across head by using the input write data drive transistors of a slower transistor type (typically PNP) on one half of an H-bridge configuration, while transistors of a faster transistor type (typically NPN) in the other half of the H-bridge configuration are driven indirectly by transistors of the slower type, with a trans-resistance in series with transistors of the faster type. Accordingly, the voltage nodes on either side of the write head are pulled to Vcc and Vee symmetrically. A trans-resistance block () uses current sources to pull current from capacitive nodes for faster switching.

7092189, Aug 15, 2006

Oct 26, 2004

10/973845

Jeremy Robert Kuehlwein - Woodbury MN, US

Texas Instruments Incorporated - Dallas TX

G11B 5/02

360 68

A write driver output circuit having a programmable output impedance. A plurality of amplifiers are disposed in parallel between an input and an output of an impedance matching section of the write driver circuit and can be selectively enabled to correspondingly set the output impedance of the write driver circuit. The amplifiers may be Class AB amplifiers, each of which have a smaller size than an conventional AB used in a single amplifier write driver circuit. Each of the Class AB amplifiers has a corresponding matching resistor, and a current source, each being selectively enabled and disabled by enabling and disabling, respectively, the corresponding current sources, such as through the use of serial interface bits.

7190541, Mar 13, 2007

Mar 14, 2006

11/375513

Jeremy Kuehlwein - Woodbury MN, US
Scott Sorenson - Lakeville MN, US

Texas Instruments Incorporated - Dallas TX

G11B 5/02
G11B 5/09
H03B 1/00

360 67, 360 46

A write driver () produces balanced voltages across head () by using the input write data (WDX and WDY) drive transistors of a slower transistor type (typically PNP) on one half of an H-bridge configuration, while transistors of a faster transistor type (typically NPN) in the other half of the H-bridge configuration are driven indirectly by transistors of the slower type, with a trans-resistance in series with transistors of the faster type. Accordingly, the voltage nodes on either side of the write head are pulled to Vcc and Vee symmetrically. A trans-resistance block () uses current sources to pull current from capacitive nodes for faster switching.

7206155, Apr 17, 2007

Sep 30, 2004

10/955424

Jeremy Kuehlwein - Woodbury MN, US
Raymond E. Barnett - Dallas TX, US

Texas Instruments Incorporated - Dallas TX

G11B 5/02

360 67, 360 66, 360 68, 360 46

A write driver circuit () uses a matching resistors (R, R) to match the impedance of the head () disposed between output nodes (OUTP, OUTN). Control circuitry (Q, Q, Q, Q, R, R, R and R) maintains the voltage at reference voltage nodes (VREFP, REFN) at essentially the same voltage as its corresponding output node. The matching resistor is disposed between the reference voltage node and the output node along with a driver (), which may be implemented as an AB driver. Since the voltage between the reference node and the output node is generally zero, very little current is shunted by the matching resistors, and thus, there is very little power wasted by the matching resistors. In the preferred embodiment, the output transistors of the AB drivers are driven by switched current sources (Q and Q) to provide enhanced current to the bases of the output transistors on an as needed basis.

7450329, Nov 11, 2008

Sep 1, 2004

10/932240

Jeremy Robert Kuehlwein - Woodbury MN, US

Texas Instruments Incorporated - Dallas TX

G11B 5/02

360 68

The present invention achieves technical advantages as a preamplifier write driver () having a varying common-mode output voltage. This varying common-mode output voltage also adjusts the derivative of the common-mode voltage, which is proportional to the amount of current coupled onto the MR head through parasitic capacitance. Currents of a first circuit (Q,Q) and a second circuit (Q,Q) are matched to overcome process variations and modeling errors. A pair of transresistance amplifiers () are driven by control lines () to achieve these matched currents.