HA16103FPJ Datasheet, PDF (7/19 Pages) Renesas Technology Corp – Watchdog Timer

HA16103FPJ/FPK
Low Voltage Monitoring Function
The system contains a circuit to send a control signal to the microcomputer when the output voltage drops. The circuit
includes the following features.
• Two-point monitoring of output voltage (V_NMI and V_STBY)
• Availability of fine adjustment of Vth1 (V_NMI) and Vth2 (V_STBY)
• Output of control signal in standby mode of microcomputer
Figure 5 shows the timing chart of control signals when the output voltage drops.
If the output voltage drops below Vth1 (4.60 V), the NMI signal rises to request the microcomputer to issue the NMI
interrupt signal. The RES signal falls t_RES seconds after the NMI signal rises. If the output voltage drops further to
below Vth2 (3.2 V), the STBY signal rises to enable the micro-computer to enter standby mode.
V_BATT
V_O
4.70 V
4.60 V
4.70 V 4.60 V
3.20 V
NMI
RES
STBY
Power on reset signal
ton
toff
t RH t RL ^{t RES}
tr
Automatic reset signal
t RES
P-RUN
System runaway
Figure 5 Timing Chart for Low Voltage Monitoring
Rev.3.00 Jun 15, 2005 page 7 of 18