Rohm Co., Ltd.

Masashi Horimoto

Yoichi Tamegai

YongMoo Heo

A power supply circuit including a DC/DC converter having switching elements and configured to receive an input voltage in an input line and generate an output voltage in an output line; and a linear regulator configured to receive the output voltage and supply a stabilized voltage to a load. The DC/DC converter switches between a switching mode to switch the switching elements and a bypass mode to put a switching element existing on a path from the input line to the output line, of the switching elements, in a full-on state and stop switching of the other switching element.

Power supply circuit, control circuit thereof, and electronic apparatus

A mobile device is configured such that it can be charged using an electric power signal Sreceived from a wireless power transmitter. A wireless power receiver receives the electric power signal S. A charger circuit charges a secondary battery using the electric power received by the wireless power receiver. A sensor detects whether or not the mobile device has been moved from a charging stand after the wireless power receiver transmits, to the wireless power transmitter, an EPT (End of Power Transfer) packet that indicates that charging of the secondary battery has been completed.

Mobile device

A semiconductor device has an IC chip main body including a power transistor and a substrate of BGA type including an insulating substrate. A plurality of external electrodes are formed on a plurality of through holes formed in the insulating substrate so as to individually penetrate from one surface to the other surface and protrude to the other surface. Further, the external electrodes are arranged in a grid pattern. Power pads among IC pads of the IC chip main body are bonded to substrate pads connected to outermost peripheral external electrodes among the external electrodes of the substrate, such that the lengths of the wires become shorter.

Semiconductor device

A multiple-output power device has a plurality of regulators for outputting regulated voltages; a plurality of power terminals for supplying an input voltage to the respective regulators; and a plurality of output terminals for outputting regulated output voltages from the plurality of regulators to the outside.

Multiple-output power device, and mobile device using the same

A semiconductor integrated circuit device has a semiconductor integrated circuit chip, a package enclosing the chip, and a plurality of conductors connecting the bonding pads of the chip to the leads of the package. The chip has an internal circuit, a plurality of bonding pads having signal paths formed between themselves and the internal circuit, and a switching circuit provided in a predetermined signal path so as to perform a switching operation to allow the internal circuit to be connected selectively to one of different bonding pads. The switching circuit is fed with an external signal to perform its switching operation in such a way as to prevent the signals passing through mutually adjacent conductors from affecting each other.

Semiconductor integrated circuit device

An amplifier has a p-type and an n-type difference transistor pairs providing respective outputs, and is adapted to provide the outputs of the pairs in an integrated form. When the level of the input signal is below a predetermined level, only the p-type difference transistor pair is activated, and when the level of the input signal is higher than the predetermined level, the n-type difference transistor pair is also activated. The amplifier has an expanded dynamic range with a suppressed noise level.

Amplifier

A DC-DC conversion type power supply unit has an error amplifier for feeding back the output voltage of the unit to one input terminal of the error amplifier during a startup of the unit. The input terminal is once fixed to a prohibition voltage that prohibits the output of the unit from being outputted therefrom for a predetermined period of time to charge up a feedback condenser. After the period, the feedback condenser discharges its electric charge to gradually raise the voltage of the input terminal to the reference voltage of the power supply unit, thereby allowing a soft start of the power supply unit without changing the reference source voltage of the unit.

Power supply unit having a soft start functionality and portable apparatus equipped with such power supply unit

An A/D conversion device has a signal input terminal for receiving an analog signal, an A/D converter for converting the received analog signal into a digital signal, and a signal output terminal for outputting the digital signal. The A/D conversion device also has a direct-current voltage input terminal for receiving a direct-current voltage from a direct-current voltage source whose output voltage can be varied. To the direct-current voltage input terminal, a first resistor, a second resistor, and a constant voltage source are connected in series in this order. To the node between the first and second resistors, the input terminal of an amplifier is connected. Between the signal input terminal and the A/D converter, an operational amplifier is connected. The operational amplifier has first and second input terminals and an output terminal, with the first input terminal connected to the signal input terminal, and with the second input terminal connected through a third resistor to the output terminal of the operational amplifier itself and connected also to the output terminal of the amplifier.

Analog-to-digital conversion device

A PHS relay station demodulates a digital signal from a received radio-frequency signal by use of a reproduction clock produced from the digital signal. The relay station has an oscillator which generates a clock and a variable-ratio frequency divider for the clock outputted from the oscillator. A bit clock is produced from the output of the divider. A signal processor processes the digital signal by use of the bit clock. A detector detects a specific code in the digital signal in synchronism with the bit clock. The length of time that passes after the specific code detection signal is generated until the reproduction clock changes its level is detected as the phase deviation between the reproduction clock and the bit clock. The phase deviation is eliminated by temporarily changing the frequency division ratio of the divider in accordance with the amount of the deviation.

Receiver circuit for a mobile communications system

A radio communication device and a cordless answer phone including base and hand sets connected with each other by radio and having a message recording and reproducing device is capable of improving sound quality of messages recorded and reproduced. A pair of switches are connected between a radio transmission and receiving device and a compandor having a compressor and an expander for the radio communication between the base and hand sets, and the sound quality improvement function of the compandor is used in recording and reproducing an answer message and a telephone message. When the message is recorded in the message recording and reproducing device, the amplitude of the sound signals is compressed, and after the compressed message is reproduced from the message recording and reproducing device, the amplitude of the sound signals of the message is expanded to enable the improvement of the sound quality.

Growing community of inventors

Kyoto, Japan

Masashi Horimoto