BD45231 ROHM [Rohm], BD45231 Datasheet - Page 6

• Manufacturer Part Number: BD45231
• Description: Counter Timer Built-in CMOS Voltage Detector IC
• Manufacturer: ROHM [Rohm]

 Circuit Applications
© 2009 ROHM Co., Ltd. All rights reserved.
BD45□□□G, BD46□□□G series
www.rohm.com
1) Examples of a common power supply detection reset circuit.
2) The following is an example of a circuit application in which an OR connection between two types of detection voltages
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 BD45□□□G
series to pull-up to the desired voltage (VDD3) as shown in Fig. 20 and make the output “High” voltage matches the power
supply voltage VDD3 of the microcontroller.
resets the microcontroller.
V
DD1
V
GND
V
DD1
DD1
BD45□□□
Fig.18 Open Collector Output Type
ER
BD46□□□
Fig.19 CMOS Output Type
BD45□□□
No.1
C
（Noise-filtering
R
L
Capacitor）
L
V
OUT
C
（Noise-filtering
L
Capacitor）
V
Microcontroller
DD2
ER
Microcontroller
BD45□□□
Fig.20
No.2
V
GND
6/9
DD2
Application examples of BD45□□□G series (Open Drain
output type) and BD46□□□G 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 (BD45□□□G) attached a
load resistance (RL) between the output and VDD2. (As
shown Fig.18)
CASE2: the power supply of the microcontroller (VDD1) is
same as the power supply of the reset detection (VDD1).
Use CMOS output type (BD46□□□G) or open drain output
type (BD45□□□G) attached a load resistance (RL)
between the output and Vdd1. (As shown Fig.19)
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).
V
OUT
R
L
R
ST
microcontroller
Technical Note
2009.05 - Rev.C
V
GND
DD3