TC1041 Datasheet, PDF (5/14 Pages) Microchip Technology – Linear Building Block . Dual Low Power Comparator and Voltage Reference with Programmable Hysteresis

TC1041
4.0 TYPICAL APPLICATIONS
The TC1041 lends itself to a wide variety of
applications, particularly in battery powered systems. It
typically finds application in power management,
processor supervisory and interface circuitry.
4.1 Precision Battery Monitor
Figure 4-1 is a precision battery low/battery dead
monitoring circuit. Typically, the battery low output
warns the user that a battery dead condition is
imminent. Battery dead typically initiates a forced
shutdown to prevent operation at low internal supply
voltages (which can cause unstable system operation).
The circuit in Figure 4-1 uses a TC1034, a TC1041 and
only six external resistors. AMP 1 is a simple buffer
while CMPTR1 and CMPTR2 provide precision voltage
detection using V_REF as a reference. Resistors R2 and
R4 set the detection threshold for BATT LOW while
Resistors R1 and R3 set the detection threshold for
BATT FAIL. The component values shown assert
BATT LOW at 2.2V (typical) and BATT FAIL at 2.0V
(typical). Total current consumed by this circuit is
typically 16µA at 3V. Resistors R5 and R6 provide
hysteresis of 116mV for both comparators.
FIGURE 4-1:
PRECISION BATTERY MONITOR
To System DC/DC
Converter
R4, 470k, 1%
V_DD
TC1034
+
AMP1
–
R2, 430k, 1%
V_DD
+
CMPTR1
–
TC1041
BATTLOW
+
3V
Alkaline
TC1041
R1, 300k, 1%
V_REF
V_DD
–
TC1041
CMPTR2
+
R5 51k
HYST
R6 1M
BATTFAIL
R3, 470k, 1%
© 2002 Microchip Technology Inc.
DS21346B-page 5