Fujitsu Corporation

Ricoh Company, Ltd.

Koichi Kawano

Mark Friesen

Kensuke Iizuka

Hisao Morooka

Nobutsugu Fujino

Shinichiro Mori

Kiyohito Hara

Lihsuan Chou

Arithmetic and control unit for data processing

In a switching regulator, a low voltage malfunction prevention circuit controls operations of a PWM comparator and a output buffer circuit, such that when a power source voltage is lower than a predetermined value, a switching transistor is forcibly turned off, and when the power source voltage is greater than or equal to the predetermined value, the switching transistor is turned on/off in accordance with pulse signals from the PWM comparator. Furthermore, the low voltage malfunction prevention circuit generates a second reference voltage that is lower than a first reference voltage and that rises quickly in accordance with the rise of the power source voltage. The state of the power source voltage inside an IC is detected by comparing the first reference voltage with the second reference voltage.

Switching regulator and operation control method

Mobile computer

Charger for mobile terminal device

Mobile phone

Growing community of inventors

Kawasaki, Japan

Koichi Kawano