Abstract: The present invention provides a switching power supply circuit capable of stabilizing an output voltage as well as increasing a response speed of the output voltage by improving a phase margin of an open loop as a whole of the switching power supply circuit. The switching power supply circuit according to the present invention includes a resistor and a capacitor in addition to a configuration of a conventional switching power supply circuit. The resistor is connected between a node and the capacitor. The capacitor is connected between the resistor and another node. The resistor and the capacitor configure a phase compensation circuit. The phase compensation circuit has a cut-off frequency in accordance with a resonance frequency of an inductor and a capacitor by adjusting a resistance value of the resistor and a capacitance of the capacitor.

Abstract: There is a need for preventing a MOS transistor from being destroyed due to an inrush current from an input terminal when a boost operation starts from a boost disabling state. During the boost operation, a third MOS transistor (M3) turns off and a fourth MOS transistor (M4) turns on to prevent a current leak from an output terminal (Vout) to an input terminal (Vin) due to a parasitic diode of a second MOS transistor (M2). In the boost disabling state, the third MOS transistor turns on and the fourth MOS transistor turns off to prevent a current leak from the input terminal to the output terminal due to the parasitic diode of the second MOS transistor. When the boost operation starts from the boost disabling state, an electrode toward the output terminal of the second MOS transistor is charged before changing a substrate bias state of this transistor. In this manner, an inrush current is prevented from flowing from the input terminal to the output terminal via the parasitic diode of the second MOS transistor.

Abstract: The present invention provides a switching power supply circuit capable of stabilizing an output voltage as well as increasing a response speed of the output voltage by improving a phase margin of an open loop as a whole of the switching power supply circuit. The switching power supply circuit according to the present invention includes a resistor and a capacitor in addition to a configuration of a conventional switching power supply circuit. The resistor is connected between a node and the capacitor. The capacitor is connected between the resistor and another node. The resistor and the capacitor configure a phase compensation circuit. The phase compensation circuit has a cut-off frequency in accordance with a resonance frequency of an inductor and a capacitor by adjusting a resistance value of the resistor and a capacitance of the capacitor.

Abstract: The present invention aims to share a semiconductor chip built-in circuit for a step-down function and a step-up function by or through one semiconductor product used as a DC/DC converter configured in a semiconductor chip. The semiconductor chip includes a switching driver, a first switch element and a second switch element. An output current path of the first switch element and an output current path of the second switch element are connected in series. A common connecting point of the first and second switch elements is connected to one end of a smoothing coil outside the semiconductor chip, and the output current path of the second switch element is connected to a base potential. An input DC voltage is supplied from the first switch element, and a step-down voltage VOUT to a load is outputted from the other end of the coil. When a method of supplying the input DC voltage and a method of performing a connection to the load are changed, a step-up voltage is outputted.

Abstract: The present invention provides a switching power supply circuit capable of stabilizing an output voltage as well as increasing a response speed of the output voltage by improving a phase margin of an open loop as a whole of the switching power supply circuit. The switching power supply circuit according to the present invention includes a resistor and a capacitor in addition to a configuration of a conventional switching power supply circuit. The resistor is connected between a node and the capacitor. The capacitor is connected between the resistor and another node. The resistor and the capacitor configure a phase compensation circuit. The phase compensation circuit has a cut-off frequency in accordance with a resonance frequency of an inductor and a capacitor by adjusting a resistance value of the resistor and a capacitance of the capacitor.