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Circuit Applications
1
）
Examples of a common power supply detection reset circuit.
Application examples of BD48
□□
G/FVE series (Open Drain
output type) and BD49
□□
G/FVE series (CMOS output type) are
shown below.
CASE1: the power supply of the microcontroller (VDD2) differs
from the power supply of the reset detection (VDD1).
Use the open drain output type (BD48
□□
G/FVE) attached a
load resistance (RL) between the output and VDD2. (As shown
Figure 15)
CASE2: the power supply of the microcontroller (VDD1) is same
as the power supply of the reset detection (VDD1).
Use CMOS output type (BD49
□□
G/FVE) or open drain output
type (BD48
□□
G/FVE) attached a load resistance (RL) between
the output and Vdd1. (As shown Figure 16)
When a capacitance CL for noise filtering is connected to the
VOUT pin (the reset signal input terminal of the microcontroller),
please take into account the waveform of the rise and fall of the
output voltage (VOUT).
2) The following is an example of a circuit application in which an OR connection between two types of detection voltages resets the
microcontroller.
When there are many power supplies of the system, power supplies VDD1 and VDD2 are being monitored separately, and it is necessary
to reset the microcomputer, it is possible to use an OR connection on the open drain output type BD48
□□
G/FVE series to pull-up to the
desired voltage (VDD3) as shown in Fig. 17 and make the output “High” voltage matches the power supply voltage VDD3 of the
microcontroller.
V
DD2
V
DD1
V
DD3
GND
Microcontroller
R
L
BD48
□□□
BD48
□□□
R
ST
V
DD1
BD48
□□□
V
DD2
GND
Microcontroller
C
L
（
Noise-filtering
Capacitor
）
R
L
Fig.15 Open Collector Output Type
C
L
(Noise-filtering
Capacitor
）
V
DD1
BD49
□□□
Microcontroller
GND
Fig.16 CMOS Output Type
Fig.17
