Abstract: An inductive current digital-to-analog converter (DAC) includes: a power supply input adapted to be coupled to a power supply; a load terminal adapted to be coupled to a load; an inductor between the power supply input and the load terminal; and inductor current control circuitry. The inductor current control circuitry has: a sense signal input configured to receive a sense signal representative of the inductor current; a control code input configured to receive a control code; a set of switches having respective control terminals; and a set of control circuit outputs coupled to the respective control terminals of the set of switches. The inductor current control circuitry is configured to adjust control signals provided to the set of control circuit outputs based on the sense signal and the control code.

Abstract: One embodiment of the invention includes a current mirror system. The system comprises a master circuit configured to conduct a first current in response to an activation state of an activation signal. The system also comprises a slave circuit configured to generate at least one second additional current in response to the activation state of the activation signal. Each of the at least one additional current can be proportional to the first current. The system further comprises a current path circuit that is configured as a substantial copy of the master circuit, the current path circuit being configured to conduct the first current in response to a deactivation state of the activation signal.

Abstract: An integrated, tuning circuit for tuning a MOSFET-C filter contains a tuning MOSFET and a differential amplifier. A current source is connected to the drain of the tuning MOSFET. The output of the amplifier is coupled to the drain of the tuning MOSFET and to a terminal that connects to the drains of the MOSFETs of the filter, so that the equivalent resistance of the filter is dependant on the current. The current source is coupled to a reference current generator, such that current supplied by the current source to the tuning MOSFET is proportional to the current supplied in the reference current generator, which in turn varies with process and environmental conditions of a capacitance. As a result, changes in process and environmental conditions oppositely affect the capacitance and resistance in the filter, resulting in a fixed RC product and fixed frequency response from the filter.

Abstract: An apparatus for demodulating two pilot tones for use by a servo control for a magnetic read head is disclosed. The apparatus provides positioning information to position the read head adjacent to a desired information track of a magnetic storage medium. The apparatus comprises a first and a second pilot tone demodulation unit. Each pilot tone demodulation unit comprises a band pass filter for providing a first filtered output signal having an amplitude and a phase representative of the first and the second frequency pilot tones, respectively. A delay lock loop receives the first filtered out of the band pass filter and determines a phase of the frequency pilot tone. A multiplier is connected to the output of the band pass filter and the output of the delay lock loop for multiplying the frequency pilot tone with the output signal of the delay lock loop. A low pass filter is connected to the output of the multiplier for filtering out undesired signals and for passing a DC signal.