Analog Devices,inc.

Analog Devices International Unlimited Company

Analog Devices Global Unlimited Company

Eduardo M Martinez

Santiago Iriarte

Alberto Marinas

Colm Donovan

Christian Jimenez

Jesus Javier Lopez

Jose Ibanez Climent

Jose Ibanez-Climent

The present disclosure provides a feedback control system and method for a bidirectional VCM. The system employs an analog core that is common to both the PWM and linear modes of operation. The analog core includes a feedback mechanism that determines the error in the current flowing through the motor. The feedback mechanism produces an error voltage that corresponds to the current error, and applies the voltage to a control driver. The control driver then controls the motor, based on the error voltage, in either a PWM or linear mode. By sharing a common core, the switching time between modes is improved. Furthermore, the output current error between modes is reduced.

Feedback control system and method

An apparatus and method for determining characterizing attributes of an actuator is provided. An actuator may be moved to a maximum capacitance position. At the maximum capacitance position, an initial measurement of the actuator capacitance is made. The actuator is moved a predetermined increment toward a first extreme position, and the actuator capacitance is again measured. If the capacitance changed by a threshold amount, the signal preceding the signal that caused the actuator to move is recorded as an approximate response curve end point, or the first extreme position. The actuator is again moved a predetermined increment toward a second extreme position. After each move, the capacitance is measured. If it is determined the capacitance did change by a threshold amount from the previously measured capacitance, the signal related to the previously measured capacitance is recorded as an approximate response curve end point, or the second extreme position.

Automatic characterization of an actuator based on capacitance measurement

A reference voltage generator circuit may include at least one MOS transistor and at least one bipolar transistor coupled together to provide an electrical path from an input reference potential to an output of the generator circuit. The electrical path may extend through a gate-to-source path of the MOS transistor and further through a base-to-emitter path of the bipolar transistor. The MOS transistor may be biased by a bias current that is proportional to T&#xb7;&#x3bc;(T), where T represents absolute temperature and &#x3bc;(T) represents mobility of a MOS transistor in the bias current generator. Optionally, the reference voltage generator may include N MOS and M multiple bipolar transistors (N&#x2267;1, M&#x2267;1), and the output reference voltage may be N*V+M*Vas compared to the input reference potential.

Reference voltage generators for integrated circuits

A detection circuit is coupled to an output terminal of a driver circuit. The detection circuit includes a comparator to compare a signal at the output terminal to a reference signal corresponding to a signal that would be generated if a capacitive load having a relatively high capacitance value were connected to the output terminal. Output of the comparator is sampled at a predetermined time after the driver circuit provides the drive signal. An error signal is generated when the sampled output indicates that the capacitive load having the relatively high capacitance value is actually connected to the output terminal.

Protection circuit for driving capacitive loads

A system for a Class AB Amplifier output stage that includes a first push pull system connected to an output terminal including a first driving transistor coupled to the output terminal and a second push pull system connected to the output terminal including a second driving transistor coupled to the output terminal. The amplifier also includes a current mode amplifier where the current mode amplifier's output is coupled to the first driving transistor's gate. The amplifier further includes a pair of resistors, a first resistor coupled to a first input terminal of the current mode amplifier, a second resistor coupled to a second input terminal of the current mode amplifier and coupled to the second driving transistor.

Growing community of inventors

Valencia, Spain

Eduardo M Martinez