LTC4100 datasheet(28/48 Pages) LINER

28 / 48 page

LTC1760

1760fa

This cached bit will remain set if a subsequent AlarmWarn-

ing() fails to respond. The cached alarm will be cleared by

any of the following conditions.

a) Associated battery is removed.

b) A subsequent AlarmWarning() clears all charge

alarm bits for the associated battery.

c) A power on reset event.

d) The SMBus Host asserts

BatterySystemStateCont(CHARGER_POR) high.

7. The SMBus Host asserts

BatterySystemStateCont(CHARGING_INHIBIT) high.

8. Hardware controlled charging inhibit is asserted (MODE

low with VDDS high).

9. The SMBus of the battery being charged has stopped

acknowledging SMBus read commands for longer than

tTIMEOUT.

10. The thermistor of the battery being charged indicates

HOT-RANGE.

11. Any SMBus communication line is grounded for longer

than tQUERY.

12.BatterySystemStateCont(POWER_NOT_GOOD)ishigh.

13. The emergency turn-off feature has been asserted

using the DCDIV input pin.

Whenever changing conditions cause either battery to

stop charging, charging is stopped immediately for all

batteries and the voltage and current algorithms are reset

to zero. Charging is not resumed until all the conditions

for controlled charging are met.

3.6 Controlled Charging Current Programming

The LTC1760 uses a single charger stage to simultaneously

charge up to two batteries. The batteries are connected to

the charger using a charge MUX. The charge MUX allows

the total charger current to be shared by the two batteries

while preventing charge transfer between the batteries.

Refer to “Section 7.1” and “Section 7.2”.

When charging a single battery, the charging algorithm

attempts to adjust the current so as to match the reported

current with the requested current. The LTC1760 continu-

ously adjusts the charging current by the difference between

the actual and requested currents.

When simultaneously charging two batteries, the charging

algorithm attempts to adjust the current so as to match

the reported current with the requested current in both

batteries. The LTC1760 calculates the difference between

the requested and actual current in both batteries and

uses the minimum of these differences to increment or

decrement the total charge current being provided by the

charging stage.

The charging algorithm will not allow the reported actual

current to exceed the requested current in either battery.

For this reason the most efficient charging occurs for

matched batteries at similar charge states.

Whenever changing conditions cause either battery to

stop charging, the current algorithm is reset to zero. The

programmed current is updated every tQUERY.

There are additional safety restrictions that limit the total

output current of the charger. These are detailed in the

following three sub-sections.

3.6.1 Current Limits When Charging A Single Battery

The following additional limits are applied to the charg-

ing current algorithm described in 3.6 when charging a

single battery:

a) The programmed current cannot exceed the requested

current + ILIMIT/32.

b) The programmed current cannot exceed ILIMIT.

3.6.2 Current Limits When Charging Two Batteries

(TURBO Mode Disabled)

The following additional limits are applied to the charging

current algorithm described in 3.6 when charging two

batteries with turbo mode disabled:

a) The programmed current cannot exceed the maximum

of the two requested currents + ILIMIT/32.

b) The programmed current cannot exceed ILIMIT.

3.6.3 Current Limits When Charging Two Batteries

(TURBO Mode Enabled)

The following additional limits are applied to the charging

current algorithm described in 3.6 when charging two

batteries with turbo mode enabled:

OPERATION

LTC4100 Datasheet(PDF) 28 Page - Linear Technology

LTC4100 Datasheet(HTML) 28 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

Datasheet Download

Link URL