| 摘要 |
A controller used in a switching power supply apparatus and a switching power supply apparatus using the controller are disclosed. The controller comprises a voltage distribution unit(5716,5717) for distributing the voltage of the power supply; an amplifier(5713) for enabling the output voltage to be reduced in case that the input voltage from the voltage distribution unit becomes large, and for enabling the output voltage to become large in case that the input voltage from the voltage distribution unit becomes small; a pulse width modulation unit(5714) for enabling the duty rate of the output pulse signal become large in case that the input signal from the amplifier becomes large, and for enabling the duty rate of the output pulse signal become small in case that the input signal from the amplifier becomes small; a low voltage isolation unit(5712) for providing a control signal which disables the output signal from the pulse width modulation unit in case that the voltage is larger that a high threshold voltage, and for providing another control signal which enables the pulse width signal from the pulse width modulation unit in case that the voltage is larger than a low threshold voltage; an AND circuit(5715) for transmitting or isolating the pulse signal from the pulse width modulation unit according to the enable or the disable; and a oscillator(5711) for inputting the power supply unit to be operated. Since, thereby, the power supply, the feedback function, and a soft start function are established on only one chip, the structure can be simple and the weight of the controller can be reduced.
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