ROHM COMPANY, LTD.
|ROHM COMPANY, LTD. Patent applications|
|Patent application number||Title||Published|
|20090021970||DC-AC CONVERTER, CONTROLLER IC THEREFOR, AND ELECTRONIC APPARATUS UTILIZING THE DC-AC CONVERTER - An inverter controls the power supplied to a load such as a CCFL connected to a secondary winding of a transformer by means of pulse width modulation (PWM) control of the switches of a semiconductor switching circuit connected to the primary winding of the transformer. The current and voltage supplied to the load are fed back to the inverter in the form of a current error signal and a voltage error signal, respectively, from which a feedback signal is formed in accordance with the magnitudes of these signals. Thus, when the DC supply voltage of a DC power supply sharply rises, the inverter changes the feedback signal directly, that is, without waiting for the changes to occur in the load current and load voltage, so as to reduce the power supplied to the load. Thus, over-current and resultant viewer's discomfort is suppressed. Sudden shut down of the inverter are also prevented from occurring.||01-22-2009|
|20080218107||Motor Drive Unit and Electric Apparatus Having a Motor - A motor drive unit capable of detecting the position of a stationary rotor of any type of sensorless motor, determining a proper startup logic for the rotor, and starting up the motor in a stable condition. To do this, multiple stator coils of the sensorless motor are supplied with rotor-position detecting drive voltages that are adapted to vary the middle point voltage of the multiple stator coils but do not rotate the motor. The middle point voltage of the stator coils is compared with a detection reference voltage. When the result of the comparison matches one of predetermined detection logic patterns, a proper startup logic is generated in accordance with the position of the rotor specified by the matching detection logic pattern to start up the motor. Otherwise, the detection reference voltage is changed in level, and a new rotor-position detecting signal is generated to repeat the procedure for detecting the rotor position.||09-11-2008|
Patent applications by ROHM COMPANY, LTD.