LTC1759 Linear Technology, LTC1759 Datasheet - Page 16

• Manufacturer Part Number: LTC1759
• Description: Smart Battery Charger
• Manufacturer: Linear Technology

OPERATIO
LTC1759
The Charger Controller Block
The LTC1759 charger operations are handled by the
charger controller block. This block is capable of charging
the selected battery autonomously or under host control.
The charger controller can request communications with
the system management host (SMHost) by asserting
INTB = 0; this will cause the SMHost, if present, to poll the
LTC1759.
The charger controller receives SMBus slave commands
from the SMBus controller block.
The charge controller allows the LTC1759 to meet the
following Smart Battery-controlled (Level 2) charger
requirements:
1. Implements the Smart Battery’s critical warning mes-
2. Operates as an SMBus slave device that responds to
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sages over the SMBus.
ChargingVoltage() and ChargingCurrent() commands
and adjusts the charger output characteristics
accordingly.
U
NOTE: NUMBERS REFER TO CONDITIONS AND STATE DESCRIPTION IN TABLE 3
CHARGING_WAKE-UP_STATE
7
0
20
3 OR 4 OR 5
OR 6 OR 16
Figure 3. Charger Controller State Machine
1 OR 2
CHARGING_RESET_STATE
CHARGING_NONE_STATE
15
15
8 OR 9
19
22
CHARGING_CONTROLLED_STATE
The charger controller allows the LTC1759 to meet the
following host-controlled (Level 3) Smart Battery charger
requirements.
1. In a host-controlled system the host is able to operate
2. The host may determine the appropriate charging algo-
3. The host may control charging by disabling the Smart
4. The LTC1759 will still respond to Smart Battery critical
The charger controller block uses the state machine of
Figure 3. The functional features for state transitions and
general control are detailed in Table 3.
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as an SMBus master device.
rithm by querying the battery or providing an alternative
special charging algorithm.
Battery’s ability to transmit ChargingCurrent() and
ChargingVoltage() request functions and broadcasting
the charging commands to the LTC1759 over the SMBus.
warning messages without host intervention.
8 OR 9
21
10 OR 11 OR 12
OR 13 OR 16
14
1759 F03
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