Sanyo VHR-H792E - Proposal for Applying Short Protection

1-4
• The Contents of Examination
As all the IC that is applied to VCR is controlled by IIC, mutual communication, if Vcc of IC is short or open
with detecting ‘Acknowledge’ data of the specific IC according to each power(5V, 5VT) µ-COM gets unable to
detect ‘ACK’ data.
µ-COM regards this case as abnormal one and if it can’t detect ‘ACK’ data for a certain time(3.5 sec) the sig-
nal of ‘Power Control’ and ‘Timer Control’ are switched to ‘Low’. As a result POWER Switching TR is kept from
generating heat and fire.
• POWER for each IC
5V POWER Modulator
5VT POWER AVCP IC
*Short protection off mode : DJ01 Diode in
PROPOSAL FOR APPLYING SHORT PROTECTION
IIC BUS
5VT SW
POWER
CONTROL
MASTER
TIMER
CONTROL
5VT SW
SLAVE with 5V
SLAVE with 5V
5.3VA
Timer Control
AVCP IC
TUNER
Conception
BLOCK Diagram
5.2V 5.2VT
• IC to detect ‘ACK’ data is selected as below because IC is different in accordance to region and option
5.3VA
Power Control
Modulator
Hi-Fi IC
NICAM IC
SECAM IC