Voltage detectors bd52xxg/fve bd53xxg/fve – Rainbow Electronics BD5323G_FVE User Manual
Page 8
For applications that voltage divided by resistance is inputted to input pin (V
DD
) of the IC if BD53XXG/FVE with
CMOS output is used, the feed through current is flowed instantly and it may cause malfunction (Oscillation at
output etc.) when output goes "H" "L". (Feed through current is the current flowed from V
DD
into GND instantly
when output goes "H" "L". )
Voltage drop ([Feed through current I1] X [ Input resistor R2]) is occurred by the feed through current when
output goes "L" to "H", and input voltage is decreased. When input voltage is decreased and become to be lower
than detection voltage, output goes "H" to "L". At this time, no feed through current flows for output L and no
voltage drop occurs. And output goes "L" to "H" again, feed through current flows and voltage drop is occurred.
This operation is repeated. This means oscillation.
2)Application circuit when microcontroller is reset with OR connection of the two types of the detection voltage
is shown below.
When there is more than one system power supply and it is necessary to individually monitor the power supply
(V
DD1
, V
DD2
) to reset the microcontroller, open drain output type BD52XXG/FVE series can be connected to form
an OR circuit as shown in Fig.19 for pulling up to an arbitrary voltage (V
DD3
) to adjust the H voltage of the output
to the microcontroller power supply (V
DD3
).
Fig.19
Fig.20
CMOS output circuit
Fig.21
Current consumption Vs. power supply voltage
8/15
Voltage detectors
BD52XXG/FVE
BD53XXG/FVE
Micro
controller
BD52XXX
NO.1
V
DD2
V
DD1
C
T
C
T
V
DD3
R
L
GND
R
ST
BD52XXX
NO.2
Micro
controller
R1
OUT
R2
V1
CT
I1
V
DD
GND
BD53XXG/FVE
V
OUT
V
DD
GND
0
V
DD
V
DET
I
DD
Feed through current
Feed through current
Rev.A