Sony Corporation

Tokio Kobayashi

Toshiya Nakabayashi

A power supply device has a pulse width control circuit for controlling voltage converting operation of a voltage converting circuit by changing a pulse width. A momentary interruption detecting circuit detects a change in an output voltage when the output voltage suffers a momentary interruption over a short period of time. A full short-circuit detecting circuit detects a change in the output voltage when the output voltage suffers a short circuit over a very short period of time. A short-circuit control circuit stops a pulse width changing control process of the pulse width control circuit a predetermined period of time after the momentary interruption detecting circuit has detected that the output voltage suffers a momentary interruption, and stops the pulse width changing control process of the pulse width control circuit immediately when the full short-circuit detecting circuit detects that the output voltage suffers a short circuit.

Power supply device

A microcomputer outputs a command to a control IC to operate first and second loads. The control IC sets first and second DC/DC converters' on-state to operate the first and second loads. The first DC/DC converter converts a voltage of power supplied from a power supply from 8.4V to 1.5V and supplies it to a constant current circuit. The constant current circuit calculates a current value of a load current to be consumed in the first load and the second load to which power is supplied via the second DC/DC converter and compares it with an electrical current value at which the utmost conversion efficiency is achievable in the first DC/DC converter. If the load current is smaller than that value, the constant current circuit supplies a surplus power to a charging battery, and if the load current is greater than that value, it receives a deficient power from the charging battery.

Growing community of inventors

Kanagawa, Japan

Tokio Kobayashi