Detecting Decrease In Voltage - Sony MZ-E30 Service Manual

5-4.

Detecting Decrease in Voltage

Fig. 5-6. shows a block diagram of the battery voltage monitor circuit. When Pin @§ [UREG CHK CON] in the system controller
becomes to "H," the VOLT CHECK (Q801) turns on. This will cause the voltage at both ends of the battery to be divided or halved
in the R801 and R802. And the voltage so halved is input to Pin 2 [UREG MON] in the system controller, thereby detecting a
decrease in voltage. A battery voltage of 0.8V or less will cause the MZ-E30 to be put into the STOP mode, with Message
"LoBATT" blinking on the remote commander display. In approximately 5 seconds, a sleep signal will be output from Pin !ª
[SLEEP] in the system controller so that the power supply circuit will stop operating. Upon wakeup, meanwhile, Pin @§ in the system
controller will change from "L" to "H" at the timing shown.
1.5[V]
1
from SERVO DRIVER IC551 VC
, pin VB1
2 3
Q801
R801
VOLT CHECK
47k
UREG MON
R802
47k
Q802
2
UREG CHK CON
1
2.8[V](VC) 0
2.7[V]
2
UREG CHK CON
0
8.5[ms]
Fig. 5-6. Battery Voltage Monitor Circuit
— 25 —
22,50,76
2
IC801
SYSTEM CONTROLLER
26
19
TO DC-DC CONVERTER IC901
30 pin SLEEP