Andrew H Crofts

6342817, Jan 29, 2002

Oct 6, 2000

09/684317

Andrew H. Crofts - Chipita Park CO
Michael A. Kultgen - Colorado Springs CO

Linear Technology Corporation - Milpitas CA

H03L 700

331 1R, 331 16, 331 17

A precision oscillator circuit providing a periodic waveform is provided. A periodic waveform is provided by the use of an integrating op-amp circuit in conjunction with a switched capacitor frequency control loop and a user input adapted to be coupled with a frequency-setting resistor. The frequency of the periodic waveform is determined by the values of the switched capacitor and the resistor. The oscillator circuit has an arrangement which minimizes the effect of the op-amp circuits offset voltage. The user input is kept robust against user-introduced capacitance by the use of controllable current sources to bias the op-amp circuit. A linearity correction circuit is also provided to correct for non-ideal op-amp circuits.

6614313, Sep 2, 2003

Nov 21, 2001

09/988930

Andrew H. Crofts - Chipita Park CO
Michael A. Kultgen - Colorado Springs CO

Linear Technology Corporation - Milpitas CA

H03L 700

331 1R, 331 16, 331 17

A precision oscillator circuit providing a periodic waveform is provided. A periodic waveform is provided by the use of an integrating op-amp circuit in conjunction with a switched capacitor frequency control loop and a user input adapted to be coupled with a frequency-setting resistor. The frequency of the periodic waveform is determined by the values of the switched capacitor and the resistor. The oscillator circuit has an arrangement which minimizes the effect of the op-amp circuits offset voltage. The user input is kept robust against user-introduced capacitance by the use of controllable current sources and/or controllable voltage sources to bias the op-amp circuit. A linearity correction circuit is also provided to correct for non-ideal op-amp circuits.

8207773, Jun 26, 2012

Jul 17, 2009

12/863699

Andrew Harvey Crofts - Coppell TX, US

Linear Technology Corporation - Milpitas CA

H03K 3/017
H03K 5/04
H03K 7/08

327175, 327172, 327173

A pulse width modulation circuit may generate an adjustable output signal that periodically transitions between a first and a second state with an adjustable duty cycle. A first pulse generator circuit may be configured to generate a first pulse signal that periodically transitions at an adjustable delay with respect to a periodic reference signal. A second pulse generator circuit may be configured to generate a second pulse signal that periodically transitions at an adjustable delay with respect to the periodic reference signal. A logic circuit may be configured to generate the adjustable output signal based on both the first and the second pulse signals.