TC54_11 Datasheet, PDF(6/20 Page) Microchip Technology – CMOS voltage detectors that are especially well suited for battery-powered

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

TC54_11 Datasheet, PDF (6/20 Pages) Microchip Technology – CMOS voltage detectors that are especially well suited for battery-powered

◁

TC54

4.0 APPLICATIONS INFORMATION

4.1 Modifying the Trip Point, VDET â

Although the TC54 has a pre-programmed VDET â, it is

sometimes necessary to make adjustments during pro-

totyping. This can be accomplished by connecting an

external resistor divider to a TC54, which has a VDET â

lower than that of VSOURCE (Figure 4-1).

To maintain detector accuracy, the bleeder current

through the divider should be significantly higher than

the 1 ÂµA operating current required by the TC54. A rea-

sonable value for this bleeder current is 100 ÂµA (100

times the 1 ÂµA required by the TC54). For example, if

VDET â = 2V and the desired trip point is 2.5V, the value

of R1 + R2 is 25 kï (2.5V/100 ÂµA). The value of

R1 + R2 can be rounded to the nearest standard value

and plugged into the equation of Figure 4-1 to calculate

values for R1 and R2. 1% tolerance resistors are

recommended.

VSOURCE

VIN

TC54

VSS

VOUT

VSOURCE ï´ R----1----R-+---1---R----2- = VDET-

Where:

VSOURCE = Voltage to be monitored

VDET â = Threshold Voltage setting of TC54

Note: In this example, VSOURCE must be

greater than (VDET â)

FIGURE 4-1:

Modify Trip-Point of the

TC54 using External Resistor Divider.

4.2 Other Applications

Low operating power and small physical size make the

TC54 series ideal for many voltage detector applica-

tions, such as those shown in Figures 4-2, 4-3 and 4-4.

Figure 4-2 shows a low-voltage gate drive protection

circuit that prevents the overheating of the logic-level

MOSFET due to insufficient gate voltage. When the

input signal is below the threshold of the TC54VN, its

output grounds the gate of the MOSFET. Figures 4-3

and 4-4 show the TC54 in conventional voltage

monitoring applications.

4.3V

270ï

VIN

TC54VX

VOUT

VCC

MTP3055EL

VSS

FIGURE 4-2:

Protection.

MOSFET Low Drive

VIN

TC54VX

VOUT

BATLOW

VSS

FIGURE 4-3:

Battery Voltage Monitor.

Pwr

Sply

VIN

TC54VX

VOUT

Power Good

VSS

DS21434J-page 6

FIGURE 4-4:

Power Good Monitor.

ï£ 2001-2011 Microchip Technology Inc.

▷