Epson PC AX Technical Manual page 41

RKV.A
2.2.2.4 Overheating Prevention Circuit
PRINCIPLES OF OPERATION
When the temperature rises to a fixed level, switch TH2 is turned on. With
switch TH2 turned on switch TH2, a comparator generates a high level signal
and it results in no pulse output of the output terminal of the HA166654.
+5V
7.5K
~""---GND
82
GND
I
TH2
15Kfi
-12V
FIGURE 2-2-20. OVERHEATING PREVENTION CIRCUIT
2.2.2.5 Power Good Signal Generation Circuit
The
pOvler
good signal generation circuit monitors the +5V line, +12V line ,-
12V line and -5V line of the secondary oscillation circuit.
If there is an abnormality (low voltage) in these lines, the power good signal
changes to low level signal.
Also, it monitors a primary voltage proportion circuit. If there is an
abnormality (low voltage) in the input AC adapter, power good signal changes
to low level signal.
The primary voltage proportion circuit is equipped with the CR circuit. The
CR circuit controls timing of the power good signal.
2-13