Ablic Inc.

Sii Semiconductor Corporation

Katsuya Goto

Akihiro Kawano

To provide a bandgap reference circuit capable of shortening a start time at power-on in a circuit lowered in power consumption. There is provided a bandgap reference circuit using an op amplifier to generate a reference voltage, which is equipped with a first current source connected between a power supply terminal and an operating current input terminal of the op amplifier, a second current source having one end connected to the power supply terminal, and a switch connected between the other end of the second current source and the operating current input terminal of the op amplifier, and in which a switch is turned on at power-on and turned off after starting of the reference voltage.

Bandgap reference circuit and DCDC converter having the same

There is provided a DC-DC converter which is safe and secure, but yet with low power consumption. The DC-DC converter is configured such that an overcurrent protection circuit is operated intermittently only for a predetermined period of time based on a signal output from an output control circuit to turn on a switching element.

DC-DC converter including an intermittent overcurrent protection circuit

To provide a switching regulator equipped with an overheat protection circuit small in current consumption. A switching regulator of the present invention is configured to intermittently operate an overheat protection circuit only for a prescribed period based on a signal turning on a switching element, which is outputted from an output control circuit.

Switching regulator

A switching regulator includes a comparator, an on-time control circuit, an R-S flip-flop circuit, and a timer circuit that outputs a count-up signal, where the comparator switches an operation current to a low current consumption mode in response to the count-up signal so as to reduce the operation current in a light load operating mode.

The DC-DC converter includes: a switching element connected between an inductor and a power supply terminal; a pseudo ripple generation circuit configured to generate a pseudo ripple voltage depending on a ripple component that is generated in the output voltage, and a smoothed voltage by smoothing the pseudo ripple voltage; a comparison circuit configured to combine a first comparison result obtained by comparing the pseudo ripple voltage and the smoothed voltage to each other, and a second comparison result obtained by comparing a reference voltage and a feedback voltage obtained by dividing the output voltage to each other, and output a comparison result signal; and an output control circuit configured to control the switching element to be turned on and off based on the comparison result signal. The comparison circuit is configured to output only the second comparison result, as the comparison result signal, when a load becomes lighter.

DC-DC converter with pseudo ripple voltage generation

There is provided a DC-DC converter which is safe and secure, but yet with low power consumption. The DC-DC converter is configured to monitor the output voltage of an error amplifier, and detect that the output voltage of the error amplifier becomes a fixed value or smaller to drive an overheat protection circuit and a supply voltage monitoring circuit intermittently.

DC-DC converter

To provide a soft start circuit capable of obtaining a high-accuracy soft start time. The soft start circuit is equipped with a constant current source, an output terminal which outputs a soft start voltage, a ground terminal, a first transistor which is connected between the constant current source and the ground terminal and has a gate and a drain both short-circuited, a second transistor which is connected between the constant current source and the output terminal and receives a clock signal at a gate thereof, and a capacitor connected between the second transistor and the ground terminal.

Soft start circuit and power supply device equipped therewith

A reference voltage generation circuit includes a bandgap reference circuit, a first resistive element and a second resistive element connected in series between the output node and a ground terminal, a third resistive element, a fourth resistive element, and a first switch connected in series between the output node and the ground terminal, and a second switch having one end connected to a connecting point of the first resistive element and the second resistive element, at which a reference voltage is generated, and the other end connected to a connecting point of the third resistive element and the fourth resistive element. A ratio between resistance values of the first resistive element and the second resistive element is equal to a ratio between resistance values of the third resistive element and the fourth resistive element. The first and second switches are turned on at power-on and turned off after the reference voltage is started.

Reference voltage generation circuit and DCDC converter having the same

To provide a COT-controlled switching regulator capable of preventing an output voltage from excessively exceeding a desired voltage even though a light load is connected to an output terminal. A switching regulator of the present invention is configured to be equipped with a 100% DUTY detection circuit which detects a 100% DUTY at which a high-side switching element continues an on state for a prescribed time or more and outputs a detected signal to an output control circuit and to cause the output control circuit to turn off the high-side switching element when the output control circuit receives the detected signal therein.

To operate a plurality of abnormality detecting functions of a switching regulator with low power consumption and configure an occupied area of a semiconductor device to be reduced. A switching regulator is configured to be equipped with a comparison circuit, switch circuits, and a switch control circuit and to switch the switch circuits by control signals of the switch control circuit and realize a plurality of abnormality detecting functions by the one comparison circuit.

Switching regulator for detecting a plurality of abnormalities using only one comparison circuit

To provide a switching regulator equipped with a power supply monitoring circuit small in current consumption. A switching regulator is configured to intermittently operate a power supply monitoring circuit only for a prescribed period based on a signal turning on a switching element, which is outputted from an output control circuit.

To provide a switching regulator equipped with an on-time control circuit small in power consumption. An on-time control circuit is configured to be equipped with switches each turned on/off by a signal controlling on and off of a switching element and be turned off during an off-time of the switching element.

Provided is a switching regulator configured to suppress noise coupling, which may occur when a comparator is switched between a normal current operation and a low current consumption operation, to thereby operate stably. The switching regulator has a configuration in which switches are connected to input terminals of the comparator, and a feedback resistor having a large resistance value is disconnected from the input terminal of the comparator when switching is performed between the normal current operation and the low current consumption operation.

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Chiba, Japan

Katsuya Goto