Harman Kardon AVR 235 Service Manual page 93

×
R 5VL
OPERATION
Ra
+
–
Rb
Rc
Operation Diagram
Released Volage +V
Supply Volage Detected Volage –V
(V )
DD
Minimum Operating Volage
GND
Output Volage
(OUT)
GND
FIG. 2 Operation Diagram
Step 1. Output Voltage is equal to Power Source Voltage (V
Step 2. When Input Voltage to Comparator reaches the state of Vref ≥ V
parator is reserved, so that Output Voltage becomes GND.
Step 3. In the case of CMOS Output, Output Voltage becomes unstable when Supply Voltage (V
case of Nch Open Drain Output, a pulled-up voltage is output.
Step 4. Output Voltage becomes equal to GND.
Step 5. When Input Voltage to Comparator reaches the state of Vref≤V
so that Output Voltage becomes equal to Supply Voltage (V
14
Tr.1
FIG. 1 Block Diagram
1 2 3
DET
A
Detector Threshold Hysteresis
DET
DD
V
DD
Pch
OUT
Nch
GND
4 5
Step
Comparator(+)Pin
Input Voltage
B
Comparator Output
Tr. 1
Pch
Output Tr.
Nch
I.
II.
t
PLH
).
·(Rb+Rc)/(Ra+Rb+Rc)at Point A (Detected Voltage –V
DD
·(Rb)/(Ra+Rb) at Point B (Released Voltage +V
DD
)
DD
× × ×
· In R 5VL A, Nch Tr. drain is con-
nected to OUT pin.
× × ×
· In R 5VL C, Nch Tr. drain and
Pch Tr. drain are connected to
OUT pin.
Step 1 Step 2 Step 3
I II II
H L Indefinite
OFF ON Indefinite
ON OFF Indefinite
OFF ON Indefinite
Rb Rc
+
·V
DD
Ra Rb Rc
+ +
Rb
·V
DD
Ra + Rb
), the output of Com-
DET
) is smaller than Minimum Operating Voltage. In the
DD
), the output of Comparator is reserved,
DET
Step 4 Step 5
II I
L H
ON OFF
OFF ON
ON OFF