Control circuit for use with switch power converter

A control circuit for use with a switch power converter, said switch power converter including a rectifying circuit, a transformer with a peripheral circuit, a DC output circuit, a controlled switch circuit and a feedback circuit for transforming an AC power to a DC voltage provided to a load, said control circuit comprising:

• a capacitor device electrically connected between a variable resistor of said feedback circuit and ground in series, said variable resistor has a resistance varying with a voltage value of said load;
• a divider resistor electrically connected between said variable resistor and said controlled switch circuit in series;
• and
• a controlled switch electrically connected among said controlled switch circuit, said divider resistor and ground,
• wherein a voltage value of said divider resistor varies with said resistance of said variable resistor to switch said controlled switch for further optionally enabling said controlled switch circuit to allow said transformer with said peripheral circuit to process an energy transformation.

A control circuit for use with a switch power converter, said switch power converter including a rectifying circuit, a transformer with a peripheral circuit, a DC output circuit, a controlled switch circuit and a feedback circuit for transforming an AC power to a DC voltage provided to a load, said control circuit comprising:

• a capacitor device electrically connected between a variable resistor of said feedback circuit and ground in series, said variable resistor has a resistance varying with a voltage value of said load;
• a first divider resistor electrically connected between said variable resistor and said controlled switch circuit in series;
• a second divider resistor electrically connected between said first divider resistor and ground in series;
• and
• a controlled switch electrically connected among said controlled switch circuit, said first divider resistor and ground,
• wherein when an overall voltage value of said first and second divider resistors increases with the decrease of said voltage value of said load, said overall voltage value of said first and second divider resistors decreases to result in turning said controlled switch off and further enabling said controlled switch circuit to allow said transformer with said peripheral circuit to process said energy transformation, and when said overall voltage value of said first and second divider resistors decreases with the increase of said voltage value of said load, said overall voltage value of said first and second divider resistors increases to result in turning said controlled switch on and further disabling said controlled switch circuit to stop said transformer with said peripheral circuit processing said energy transformation.