TC52 Datasheet, PDF (4/10 Pages) Microchip Technology – Dual Channel Voltage Detector

TC52
4.0 APPLICATIONS INFORMATION
Pin 2 (V_IN1) acts as both the input to Voltage Detector
#1, as well as the power supply input for the chip. As
such, always assign V_IN1 to monitor voltages between
1.5V and 10V. Failure to do this will result in unreliable
detector operation due to an out-of-tolerance supply
voltage. In high noise environments, it may be
necessary to install a small input bypass capacitor
(0.01µF to 0.1µF) from V_IN1 to ground to minimize on-
chip power supply noise.
4.1 Battery and Main Supply Monitor
The circuit shown in Figure 4-1 provides both a
processor supply monitor/reset function, as well as a
low battery detect function. As shown, the
TC52N3330ECT (N-Channel outputs) uses Detector 2
to monitor the system power supply rail. When the
power supply is 10% below its nominal output voltage
rating, the V_OUT2 output is driven and held low. When
the power supply voltage is above 3.0V nominal, V_OUT2
is driven to an open circuit and the combination of R₁
and C₁ provides a reset time out delay. Detector 1
monitors the voltage on the main supply battery. A low
battery condition is indicated when the battery voltage
falls to 3.3V, at which time the main processor is
interrupted to initiate a warning or system shutdown.
FIGURE 4-1:
SUPPLY MONITOR AND PROCESSOR SUPERVISOR
+
6V
– _Battery
TC105
Step Down
DC/DC
Converter
System
3.3V
V_IN2 ^VOUT2
GND
TC52N3330ECT
V_IN1 V_OUT1
+3.3V
R₁
47K
+ _C1
– 1µF
RESET
+3.3V
R₂
47K
Processor
INT
DS21430B-page 4
 2002 Microchip Technology Inc.