Rohm Co., Ltd.

Masaru Sakai

Kiyotaka Umemoto

Takuya Okubo

Shogo Hachiya

An output monitoring comparator outputs an ON signal when an output voltage becomes lower than a reference voltage. A pulse modulator generates a pulse signal at a predetermined level, an ON time-period from when the ON signal is outputted. A driver circuit alternately turns ON, after a dead time, a switching transistor and a synchronous rectification transistor, based on the pulse signal. A light load mode detector compares a switching voltage at a connection point of the switching transistor and the synchronous rectification transistor, and ground potential, and at timing at which the ON signal is outputted from the output monitoring comparator, when the switching voltage is higher than the ground potential, nullifies the ON signal.

Control circuit for synchronous rectification type step-down switching regulator

Step-down switching regulator

A control signal generating circuit () comprises a comparator () for comparing an output voltage Vwith a reference voltage outputted from a reference voltage source (), a flipflop () set by the output of the comparator (), and a pulse control circuit () which receives an input voltage V, a reference voltage V, and the inverted output of the flipflop (), sets the on time in accordance with the ratio between the input voltage Vand the reference voltage V, and resets the flipflop () when the on time elapses after the output pulse of the flipflop () rises. The output pulse of the flipflop () is outputted as a control signal into a driver logic circuit (). The driver logic circuit () performs on/off control of NMOSs () according to the control signal. Thus, a switching regulator capable of operating at high speed can be realized.

Switching regulator

The present invention provides a power supply device which can suppress a voltage drop of the input power supply immediately after recovery from shutdown status. The power supply device comprises a reference voltage generation circuit for generating reference voltage (VREF), a transistor for feeding disposed between an input terminal (VTT_IN) and an output terminal (VTT output terminal), a transistor for discharging disposed between a ground potential and a VTT output terminal, a first and second differential amplification circuits for controlling the transistors for feeding and discharging respectively by inputting the output power supply voltage (VTT) as feedback and comparing it with VREF, and a shutdown recovery circuit for generating voltage that gradually starts up by a constant current source and a capacitor, wherein the first differential amplification circuit compares VTT with the voltage (SR) of the shutdown recovery circuit instead of VREF, for a certain period from the point of recovery from shutdown status.

Power supply device and electronic equipment comprising same

A semiconductor integrated circuit comprises a semiconductor substrate, a heat-producing circuit element formed in a multi-layer structure on the semiconductor substrate and performing a predetermined operation while producing heat of a relatively high temperature, a plurality of temperature-dependent circuit elements, each formed in a multi-layer structure in a predetermined location on the semiconductor substrate, performing a predetermined operation depending on temperature of the heat-producing circuit element, and each having a constant relationship in temperature-related properties with each another, and a heat conductive layer having a heat conductivity higher than a heat conductivity of the semiconductor substrate, and covering at least a heat-producing portion of the heat-producing circuit element and the plurality of temperature-dependent circuit elements continuously so as to conduct the heat produced by the heat-producing circuit element to the plurality of temperature-dependent circuit elements. With this structure, the semiconductor integrated circuit can maintain its intended operating accuracy regardless of changes in temperature.

Growing community of inventors

Kyoto, Japan

Masaru Sakai