Abstract: A DC to DC converter circuit includes circuitry for generating a PWM waveform signal at a phase node of a DC to DC converter responsive to an input voltage and a monitor output voltage. The circuitry further includes a high side switching transistor connected between the input voltage and a phase node and a low side switching transistor connected between the phase node and ground. An output filter is connected to the circuitry for generating the PWM waveform signal. The output filter includes an inductor having a first side connected to the phase node and a second side connected to an output voltage node. Detection circuitry detects zero current crossings in the inductor responsive to a voltage across the high side switching transistor and a voltage across the low side switching transistor.

Abstract: Managing temperature of a read/write head (120) in a disk drive system in which there is a power variance due to different operation modes. A circuit device (100) determines and delivers additional power needed for compensating for the temperature variance due to different operational power requirements. The power is delivered to a resistive heater (Rheat) associated with the head (120). The compensating power is based on the delivery voltage, delivery current, and resistance of the resistive heater (Rheat). The delivery current is varied to account for changes in the resistance of the resistive heater (Rheat) since it can vary with temperature. By sensing the current with a sensor (13), the resistance is determined via the sensed current and the delivery voltage. The current is adjusted for maintaining the compensating power.

Abstract: Managing temperature of a read/write head (120) in a disk drive system in which there is a power variance due to different operation modes. A circuit device (100) determines and delivers additional power needed for compensating for the temperature variance due to different operational power requirements. The power is delivered to a resistive heater (Rheat) associated with the head (120). The compensating power is based on the delivery voltage, delivery current, and resistance of the resistive heater (Rheat). The delivery current is varied to account for changes in the resistance of the resistive heater (Rheat) since it can vary with temperature. By sensing the current with a sensor (13), the resistance is determined via the sensed current and the delivery voltage. The current is adjusted for maintaining the compensating power.

Abstract: A fly height controller (10FHC; 10FHC?) for controlling the fly height of a read/write head assembly (15) in a disk drive (20) is disclosed. A heat element resistor (30) is disposed within the read/write head assembly (15). The fly height controller (10FHC; 10FHC?) includes registers (32R, 32W) for storing digital data words corresponding to the desired drive levels to be applied to the heat element resistor (30) during read and write operations. The registers (32R, 32W) are selectively coupled to a steady-state digital-to-analog converter (DAC) (36), depending upon whether a read or write operation is occurring; the output of the steady-state DAC (36) is applied to a voltage driver (40), which in turn drives current into the heat element resistor (30). Overdrive and underdrive transistors (44P, 44N) are provided to overdrive and underdrive the input to the voltage driver (40) in transitions between read and write operations.

Abstract: Managing temperature of a read/write head (120) in a disk drive system in which there is a power variance due to different operation modes. A circuit device (100) determines and delivers additional power needed for compensating for the temperature variance due to different operational power requirements. The power is delivered to a resistive heater (Rheat) associated with the head (120). The compensating power is based on the delivery voltage, delivery current, and resistance of the resistive heater (Rheat). The delivery current is varied to account for changes in the resistance of the resistive heater (Rheat) since it can vary with temperature. By sensing the current with a sensor (13), the resistance is determined via the sensed current and the delivery voltage. The current is adjusted for maintaining the compensating power.

Abstract: Managing temperature of a read/write head (120) in a disk drive system in which there is a power variance due to different operation modes. A circuit device (100) determines and delivers additional power needed for compensating for the temperature variance due to different operational power requirements. The power is delivered to a resistive heater (Rheat) associated with the head (120). The compensating power is based on the delivery voltage, delivery current, and resistance of the resistive heater (Rheat). The delivery current is varied to account for changes in the resistance of the resistive heater (Rheat) since it can vary with temperature. By sensing the current with a sensor (13), the resistance is determined via the sensed current and the delivery voltage. The current is adjusted for maintaining the compensating power.

Abstract: A fly height controller (10FHC; 10FHC?) for controlling the fly height of a read/write head assembly (15) in a disk drive (20) is disclosed. A heat element resistor (30) is disposed within the read/write head assembly (15). The fly height controller (10FHC; 10FHC?) includes registers (32R, 32W) for storing digital data words corresponding to the desired drive levels to be applied to the heat element resistor (30) during read and write operations. The registers (32R, 32W) are selectively coupled to a steady-state digital-to-analog converter (DAC) (36), depending upon whether a read or write operation is occurring; the output of the steady-state DAC (36) is applied to a voltage driver (40), which in turn drives current into the heat element resistor (30). Overdrive and underdrive transistors (44P, 44N) are provided to overdrive and underdrive the input to the voltage driver (40) in transitions between read and write operations.

Abstract: The present invention relates to a trimmable oscillator circuit which comprises a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto. The oscillator circuit further comprises an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit, and the oscillator circuit also comprises a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor. The charge/discharge circuit is operable to charge or discharge the output capacitor based on the control signal, wherein a rate of charge or discharge is dictated by one or more user selectable control signals. Thus an oscillation frequency of the oscillator circuit may be trimmed.

Abstract: The present invention relates to a trimmable oscillator circuit which comprises a comparator circuit operable to compare an output voltage of the oscillator circuit to a reference voltage and output a control signal in response thereto. The oscillator circuit further comprises an output capacitor, wherein a voltage at a node of the capacitor comprises the output voltage of the oscillator circuit, and the oscillator circuit also comprises a selectively trimmable charge/discharge circuit coupled between the comparator circuit and the output capacitor. The charge/discharge circuit is operable to charge or discharge the output capacitor based on the control signal, wherein a rate of charge or discharge is dictated by one or more user selectable control signals. Thus an oscillation frequency of the oscillator circuit may be trimmed.

Abstract: A system and method is provided for monitoring a voltage level of a charge pump device. The system and method employ a first charging device that is coupled to an output of a charge pump through a switching system. The first charging device is then decoupled from the output of the charge pump device and coupled to a second charging device. The charge on the first charging device is then redistributed between the first charging device and the second charging device. The output of the second charging device is a reduced voltage (e.g., below 5 volts) based on the ratio of the charge distribution between the first and second charging devices. The output of the second charging device can then be compared to a reference voltage to determine if the voltage of the charge pump device is at an adequate voltage level.

Abstract: A system and method is provided for monitoring a voltage level of a charge pump device. The system and method employ a first charging device that is coupled to an output of a charge pump through a switching system. The first charging device is then decoupled from the output of the charge pump device and coupled to a second charging device. The charge on the first charging device is then redistributed between the first charging device and the second charging device. The output of the second charging device is a reduced voltage (e.g., below 5 volts) based on the ratio of the charge distribution between the first and second charging devices. The output of the second charging device can then be compared to a reference voltage to determine if the voltage of the charge pump device is at an adequate voltage level.