PURPOSE: To prevent the influence of a fault from extending at the time of the power fault in the printed board adopting the onboard type power supply system with respect to the fault protection circuit for printed board in a device provided with plural printed boards.
CONSTITUTION: A device consists of plural printed boards which perform the inter-package communication by bus connection, and each printed board 12 has an onboard type power source part 4, and power is turned on/off for each printed board in accordance with insertion/extraction of the printed board, and a pull-up resistor 15 is provided in the connection part between the power source part and the bus to keep the input part in a normal level corresponding to no signal at the time of no signal. In this device, a diode 16 is connected in series to the pull-up resistor 15 to prevent the reverse current from the connection part at the time of power-off.
KUSAYANAGI MICHIO
TAKIZAWA YUJI
KONDO RYUICHI
TATEISHI HIROOMI
