LTC2960

13

2960fa

For more information www.linear.com/LTC2960

Typical applicaTions

Figure 8. Configurable Regulator UVLO and Low Battery Indicator

Configurable Regulator UVLO and Low Battery

Indicator

In the circuit of Figure 8, the high voltage open drain

OUT output is used as a configurable UVLO signal for a

switching regulator. A Li-Ion battery can contain protec-

tion circuitry that open circuits its terminals through an

internal switch when it reaches 2.5V. With a threshold of

5.537V the LTC2960 OUT output disables the load before

this occurs in order to prevent damage to the batteries.

In addition to the UVLO signal, the LTC2960 provides a

low battery indicator for the system. Figure 9 shows an

alternative arrangement in which the LTC2960 monitors

the output of the 3.3V regulator to provide a reset signal.

LTC2960-1

LT3991

GND

EN

ADJ

RT

GND

MR

RST

OUT

R3

5.11M*

Li-Ion

4.2V

Li-Ion

4.2V

R2

49.9k

6V TO 8.4V

3.3V

C1

0.1µF

25V

R1

348k

LOW BATTERY

R5

1M

R4

10M

2960 F08

C2

47µF

16V

UVLO FALLING THRESHOLD = 5.537V

RESET FALLING THRESHOLD = 6.33V

NOT ALL LT3991 COMPONENTS SHOWN

BUCK CONVERTER

+

+

*VISHAY-DALE CRCW SERIES 0603 1%

Figure 9. Configurable Regulator UVLO and Supervisor

LTC2960-1

LT3991

GND

EN

RT

GND

MR

ADJ

RST

OUT

R2

6.04M

Li-Ion

4.2V

Li-Ion

4.2V

6V TO 8.4V

3.3V

C1

0.1µF

25V

R1

402k

10k

RESET

R6

1M

R4

2.26M

R3

402k

R5

10M

2960 F09

UVLO FALLING THRESHOLD = 6.410V

RESET FALLING THRESHOLD = 2.649V

*OPTIONAL RESISTOR FOR ADDED ESD PROTECTION

+

+

C2

47µF

16V

NOT ALL LT3991 COMPONENTS SHOWN

BUCK CONVERTER