Patent ID: 8736209
Filing Date: 2014-05-27
Classification: H02P

Abstract:
1. A drive and control circuit for a motor system, wherein the motor system comprises a rotor, a coil and a bridge circuit, the drive and control circuit comprising: a control unit configured to generate a plurality of control signals to control the bridge circuit and to generate a pulse signal indicative of the position of the rotor; a state detecting circuit coupled to the control unit to receive the pulse signal, and based on the pulse signal, the state detecting circuit generates a state detecting signal indicative of the state of the motor system, wherein the state of the motor system comprises a running state and a stop state; a load determining circuit configured to detect an ambient temperature and to generate a load determining signal based on the detected ambient temperature; and a minimum limit circuit configured to generate a minimum signal; a load sensing circuit configured to sense a load of the motor system, and to generate a threshold signal indicative of the load of the motor system; and a first comparator having a first input terminal, a second input terminal, a third input terminal and an output terminal, wherein the first input terminal is configured to receive the threshold signal, the second input terminal is configured to receive the minimum signal, and the third input terminal is configured to receive a sawtooth signal, and wherein based on the threshold signal, the minimum signal and the sawtooth signal, the first comparator generates the load determining signal at the output terminal; and a startup setting circuit configured to receive the state detecting signal and the load determining signal, and to generate a second logic signal based on the state detecting signal and the load determining signal; wherein the control unit receives the state detecting signal and the second logic signal, and generates the plurality of control signals based on the state detecting signal and the second logic signal.