LTC4015_15 Datasheet, PDF (73/76 Pages) Linear Technology – Multichemistry Buck Battery Charger Controller with Digital Telemetry System

LTC4015
DETAILED Register Descriptions
NUMBER OF
CELLS
Invalid
1
2
3
4
5
6
7
8
9
Invalid
Invalid
12*
*Lead-acid only
CELLS2
L
L
L
L
L
L
L
L
L
H
H
H
H
CELLS1
L
L
H
H
L
Z
H
Z
Z
L
L
H
H
CELLS0
L
H
L
H
Z
L
Z
H
Z
L
H
L
H
ICHARGE_DAC (Sub-Address 0x44, Bits 4:0, R)
This register represents the actual charge current setting applied to the charge current reference DAC. ICHARGE_DAC
is ramped up/down to implement digital soft-start/stop. The LTC4015 sets the value of ICHARGE_DAC based on
battery chemistry, charger state (CHARGER_STATE), thermistor reading (NTC_RATIO), and charger settings including
ICHARGE_TARGET, ijeita_n, and TJEITA_n. Recall that the charge current is regulated by controlling the voltage across
an external current sense resistor R_SNSB. The servo voltage is given by (ICHARGE_DAC + 1) • 1mV. The charge current
servo level is thus given by (ICHARGE_DAC + 1) • 1mV/R_SNSB.
VCHARGE_DAC (Sub-Address 0x45, Bits 5:0, R)
This register represents the actual target battery voltage setting applied to the charge voltage reference DAC. The
LTC4015 sets the value of VCHARGE_DAC based on battery chemistry, charger state (CHARGER_STATE), thermistor
reading (NTC_RATIO), and charger settings including VCHARGE_SETTING, vjeita_n, TJEITA_n, VABSORB_DELTA,
VEQUALIZE_DELTA,en_jeita, and en_lead_acid_temp_comp. See also JEITA Temperature Qualified Charging and
Lead-Acid Temperature Compensated Charging.
IIN_LIMIT_DAC (Sub-Address 0x46, Bits 5:0, R)
This register represents the actual input current limit setting applied to the input current limit reference DAC. This
register follows IIN_LIMIT_SETTING.
VBAT_FILT (Sub-Address 0x47, Bits 15:0, R)
Digitally filtered two’s complement ADC measurement result for battery voltage.
ICHARGE_BSR (Sub-Address 0x48, Bits 15:0, R)
This 16-bit two's complement word is the value of IBAT (0x3D) used in calculating BSR.
TELEMETRY_VALID (Sub-Address 0x4A, Bit 0, R)
This bit being set to 1 indicates the output of the LTC4015's telemetry system is valid.
For more information www.linear.com/LTC4015
4015f
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