[C] The VOLTAGE_PROT (pin25) is the port to detect abnormalities of the power supply circuit for Digital part.
1. Detection of an abnormality in the +5V-DIG, 33_VCC_USB_B or V+3.3D1.
If the +5V-DIG, 33_VCC_USB_B or V+3.3D1 of power supply is not received.
Q703, Q704 and Q705 will turn on to change the signal from the VOLTAGE_PROT (pin25) to “
Hi
” from “
Lo
”.
If the above abnormality is detected, the signal from the P_ON (pin78) terminal will be changed to "
Lo
" from "
Hi
", the
power relay
S8501
will be turned off and the unit will be shut down. Then, the STANDBY indicator ickers and indicates
that an abnormality has occurred.
This protection operation is intended for a breakdown of the digital power supply circuit and immediately shuts off the
power in order to avoid the risk of damage.
To check if the digital power supply circuit is broken, switch off the power and then switch it on again one minute later. This
action will deactivate the protection operation.
21
To Next Page
Loading...
