Abstract: A drive and control circuit for motor system and the method thereof are disclosed. The motor system could be applied in a cooling device, wherein the motor system comprises a rotor, a coil and a bridge circuit. The drive and control circuit comprises a control unit, a state detecting circuit, a load determining circuit, and a startup setting circuit. The startup setting circuit makes the motor run with the maximum torque, thus to make the motor system start up easily and quickly. The load determining circuit detects the load of the motor system, thus to generate a load determining signal to determine the speed of the motor system. The control unit could be realized with few components so as to save the costs.

Abstract: The embodiments of the present circuit and method disclose a bridge rectifier and a driving circuit. The bridge rectifier having a first input, a second input, a first output, and a second output may comprise two high side diodes and two low side switches. The driving circuit may be coupled to the first input of the bridge rectifier and the second input of the bridge rectifier, and the driving circuit may be configured to provide a first driving signal and a second driving signal. The first driving signal may be coupled to a first low side switch and the second driving signal may be coupled to a second low side switch. The first driving signal may be limited to less than a first predetermined driving voltage and the second driving signal may be limited to less than a second predetermined driving voltage.

Abstract: The present disclosure discloses a voltage regulator comprising a trimming circuit. The present disclosure also discloses a method for trimming an output voltage of a voltage regulator. In one embodiment the voltage regulator may comprise a power conversion module, a feedback and trimming module and a control module. The voltage regulator may be able to provide an output voltage that could be regulated to a plurality of output values, the feedback and trimming module may be able to trim the plurality of output values to their desired values successively and independently.

Abstract: A DC brushless motor system is disclosed. When a rotor of the DC brushless motor is close to an aligned position, there will be current spike in the coil and voltage spike in an input capacitor. By decreasing the peak current limit of the current in the coil when the rotor is close to the aligned position, the current spike and the voltage spike are reduced.

Abstract: A frequency limitation method used in a quasi-resonant controlled switching regulator is disclosed. The switching frequency is limited by setting a minimum time period, such as a minimum switching period or a minimum OFF time period. The minimum time period is varying according to the difference between the minimum time period of the previous cycle and an offset value, so as to eliminate the audible noise caused by the frequency hopping when the minimum OFF time period is close to the valley of a quasi-resonant signal.