© 2002 Microchip Technology Inc.

DS21346B-page 5

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

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 16

µA at 3V. Resistors R5 and R6 provide

hysteresis of 116mV for both comparators.

FIGURE 4-1:

PRECISION BATTERY MONITOR

R2, 430k, 1%

R4, 470k, 1%

R3, 470k, 1%

R1, 300k, 1%

To System DC/DC

Converter

3V

Alkaline

TC1041

BATTFAIL

BATTLOW

CMPTR1

+

–

CMPTR2

+

–

AMP1

+

–

+

TC1034

TC1041

TC1041

HYST

51k

R6

R5

1M