SWITCHING CONTROL CIRCUIT AND SWITCHING POWER SUPPLY DEVICE
First Claim
1. A switching control circuit for use in a power conversion circuit in a switching power supply device and includes a semiconductor integrated circuit to control a switching element, the switching control circuit comprising:
- a plurality of external terminals including a feedback signal input terminal arranged to receive a feedback signal that is generated by the power conversion circuit in response to an operation of the switching control circuit;
an output voltage stabilization control unit configured to control stabilization of an output voltage in accordance with a signal input into the feedback signal input terminal; and
a protected operation mode setting unit configured to detect a voltage induced by an external circuit that is connected to the feedback signal input terminal and that includes a resistor element or a semiconductor element, as a determination target signal, and to set one of a hiccup mode in which an oscillation period and a suspension period are repeated and a latch mode in which oscillation is stopped in accordance with the determination target signal in an overload state or an overvoltage output state.
1 Assignment
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Accused Products
Abstract
A switching control IC outputs a rectangular wave signal from an output terminal thereof to a driving circuit. A feedback circuit compares a value of a divided voltage of a voltage across output terminals of a switching power supply device with a reference voltage, generates a feedback signal, and inputs the feedback signal into a feedback terminal of the switching control IC. A capacitor and a Zener diode are connected between the feedback terminal and a ground terminal. The Zener diode is selectively connected, and a voltage at the feedback terminal is changed in accordance with the presence of the Zener diode. A voltage at the feedback terminal is detected, and one of a latch method and a hiccup method is selected as a method for an overcurrent protection operation in accordance with the detected voltage.
28 Citations
13 Claims
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1. A switching control circuit for use in a power conversion circuit in a switching power supply device and includes a semiconductor integrated circuit to control a switching element, the switching control circuit comprising:
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a plurality of external terminals including a feedback signal input terminal arranged to receive a feedback signal that is generated by the power conversion circuit in response to an operation of the switching control circuit; an output voltage stabilization control unit configured to control stabilization of an output voltage in accordance with a signal input into the feedback signal input terminal; and a protected operation mode setting unit configured to detect a voltage induced by an external circuit that is connected to the feedback signal input terminal and that includes a resistor element or a semiconductor element, as a determination target signal, and to set one of a hiccup mode in which an oscillation period and a suspension period are repeated and a latch mode in which oscillation is stopped in accordance with the determination target signal in an overload state or an overvoltage output state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification