UPD784915B Datasheet, PDF (44/86 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784915B, 784916B
(3) CFG amplifier
The CFG amplifier amplifies the capstan FG (CFG) signal that indicates the speed information of the capstan
motor. This amplifier consists of an operational amplifier and a comparator. The gain of the operational amplifier
is set by using an external resistor.
When the gain of the operational amplifier is set to 50 dB, the output duty accuracy of the CFG signal can be
improved to 50.0 ± 0.3%.
Capstan FG signal
Figure 3-21. Block Diagram of CFG Amplifier
VREF
AMPC.3
CFGIN
+ _{CFG amplifier}
-
CFGAMPO
VREF
AMPM0.0
CFGCPIN
AMPC.3
AMPC.3
CFG
-
comparator
1
+
0
CFG signal
(to timer unit)
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