LTC4101EG Просмотр технического описания (PDF) - Linear Technology

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LTC4101EG

Smart Battery Charger Controller

Linear Technology 

LTC4101

OPERATION

table defines the maximum permissible value of CHARG-

ING_VOLTAGE that will not set the VOLTAGE_OR in the

ChargerStatus() function for a given value of RVLIM:

RILIM

Short to GND

10kΩ ±1%

33kΩ ±1%

100kΩ ± 1%

Open (or short to VDD)

Maximum ChargingVoltage()

0x1090 (4240mV)

0x10D0 (4304mV)

0x1150 (4432mV)

0x11A0 (4512mV)

0x1580 (5504mV)

AlarmWarning() ('h16)

Description: The Smart Battery, acting as a bus master

device, sends the AlarmWarning() message to the LTC4101

to notify it that one or more alarm conditions exist. Alarm

indications are encoded as bit fields in the Battery’s Status

register, which is then sent to the LTC4101 by this func-

tion.

Purpose: The LTC4101 will use the information sent by

this function to properly charge the battery. The LTC4101

will only respond to certain alarm bits. Writing to this

function does not necessarily cause an alarm condition

that inhibits battery charging.

• SMBus Protocol: Write Word.

Input: Only the OVER_CHARGED_ALARM, TERMINATE

_CHARGE_ALARM, reserved (0x2000), and OVER

_TEMP_ALARM bits are supported by the LTC4101.

Writing a one to any of these specified bits will inhibit

the charging by the LTC4101 and will set the ALARM_

INHIBITED bit in the ChargerStatus() function. The

TERMINATE_DISCHARGE_ALARM, REMAINING_

CAPACITY_ALARM, REMAINING_TIME_ALARM, and the

ERROR bits are ignored by the LTC4101.

LTC0() ('h3C)

Description: The SMBus Host uses this command to

determine the version number of the LTC4101 and set

extended operation modes not defined by the Smart Bat-

tery Charger Specification.

Purpose: This function allows the SMBus Host to deter-

mine if the battery charger is an LTC4101. Identifying the

manufacturer and version of the Smart Battery Charger

permits software to perform tasks specific to a given

charger. The LTC4101 also provides a means of disabling

the LOWI current mode of the IDAC.

• SMBus Protocol: Write Word.

Input: The NO_LOWI is the only bit recognized by this

function. The default value of NO_LOWI is zero. The

LTC4101 LOWI current mode provides a more accurate

average charge current when the charge current is less

than 1/16 of the full-scale IDAC value. When the NO_LOWI

is set, a less accurate IDAC algorithm is used to generate

the charging current, but because the charger is not pulsed

on and off, it may be preferred.

• SMBus Protocol: Read Word.

Output: The NO_LOWI indicates the IDAC mode of opera-

tion. If clear, then the LOWI current mode will be used

when the charging current is less than 1/16 of the full-

scale IDAC value.

The LTC Version Identification will always be 0x4040 for

the LTC4101.

Alert Response Address (ARA)

Description: The SMBus system host uses the Alert

Response Address to quickly identify the generator of an

SMBALERT# event.

Purpose: The LTC4101 will respond to an ARA address

0x18 if the SMBALERT signal is actively pulling down the

SMBALERT# bus. The LTC4101 will follow the prioritiza-

tion reporting as defined in the System Management Bus

Specification, Version 1.1, from the SBS Implementers

Forum.

• SMBus Protocol: A 7-bit Addressable Device Re-

sponds to an ARA.

Output: The Device Address will be sent to the SMBus

system host. The LTC4101 Device address is 0x12.

The following events will cause the LTC4101 to pull-down

the SMBALERT# bus through the SMBALERT pin:

• Change of AC_PRESENT in the ChargerStatus() func-

tion.

• Change of BATTERY_PRESENT in the ChargerStatus()

function.

• Setting ALARM_INHIBITED in the ChargerStatus()

function.

• Internal power-on reset condition.

4101fa

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