Bcd Semiconductor Manufacturing Limited

Shanghai Sim-bcd Semiconductor Manufacturing Limited

Zhihong Zhang

Xujiang Huang

Food sealed storage bag

The present invention relates to a system and method controlling motor rotation speed and provides a cooling system and method configured to control a temperature associated with an integrated circuit. The cooling system includes a brushless motor, a temperature monitoring input, a clock input, and a motor controller. The motor controller is configured to control the rotational speed of the motor using at least a speed control method by comparing the environmental temperature signal to a predetermined threshold: if the environmental temperature signal is less than the predetermined threshold Tor higher than T, controlling the rotational speed of the motor uses the speed control method and only one of the environmental temperature signal and the clock signal; and if the environmental temperature signal is greater than the predetermined threshold Tand less than T, controlling the rotational speed of the motor uses the speed control method and both of the environmental temperature signal and the clock signal.

System and method for regulating motor rotation speed

A pulse width modulated (PWM) controller includes a triangle wave generation circuit generating a triangle wave signal to oscillate between an upper limit voltage and a lower limit voltage. The upper limit voltage and the lower limit voltage are adjustable in response to changes in the power supply voltage. A pulse generation circuit is coupled to the triangle wave generation circuit and a minimum duty cycle setting voltage, and is configured to generate a PWM pulse signal with a minimum duty cycle determined by the relative magnitude of the triangle wave signal and the minimum duty cycle reference voltage. In an embodiment, the minimum duty cycle is increased when the power supply voltage is lower than a predetermined reference voltage.

PWM control circuit having adjustable minimum duty cycle

A pulse width modulated (PWM) controller has an input terminal for receiving a pulsed input signal having a first duty cycle, a power supply terminal for receiving a power supply voltage. a minimum duty cycle reference voltage signal, and a control circuit for providing a pulse-width-modulated (PWM) output signal having a second duty cycle related to the first duty cycle of the pulsed input signal. The PWM output control signal having a minimum duty cycle that is adjustable in response to a change in the power supply voltage. In an embodiment, the second duty cycle and the first duty cycle are correlated in a substantially linear relationship. In an embodiment, the PWM control circuit also has a triangle wave generation circuit for generating a triangle wave signal configured to oscillate between an upper limit voltage and a lower limit voltage, which are adjustable in response to a change in the power supply voltage.

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Shanghai, China

Zhihong Zhang