LTC4020_15 Datasheet, PDF (34/42 Pages) Linear Technology – 55V Buck-Boost Multi-Chemistry Battery Charger

LTC4020
APPLICATIONS INFORMATION
LTC4020 Constant-Current/Constant-Voltage (CC/CV) Charging Diagram
START
INDICATE NOT
CHARGING
NO
POWER
AVAILABLE?
YES
BGATE PULLED
LOW
CLEAR LOW BATTERY
AND SAFETY TIMERS
NO
V_FB < 2.5 – ε?
YES
INDICATE CHARGING
TERMINATED
NTC
YES
OUT-OF-RANGE?
NO
INDICATE CHARGING
BGATE PULLED LOW
TRICKLE CHARGE
(7%)
NO
TIMER ACTIVE?
YES
RUN LOW BATTERY
TIMER
YES
V_FB < 1.75?
NO
YES
V_FB > 2.5 – ε?
NO
CHARGE AT
CONSTANT-CURRENT
NO
TIMER AT 1/8
EOC?
YES
STOP CHARGING
YES
V_FB = 2.4375V
NO
BGATE PULLED HIGH
INDICATE BAD
BATTERY FAULT
NO
V_FB > 1.75?
YES
STOP CHARGING
INDICATE NTC
FAULT
ENABLE IDEAL
DIODE FUNCTION
NO
TIMERS ACTIVE?
YES
PAUSE TIMERS
CHARGE TO FIXED
VOLTAGE
NO
I_BAT < C/10?
YES
INDICATE NOT
CHARGING
NO
TIMER ACTIVE?
YES
RUN SAFETY TIMER
NO
I_BAT < C/10?
YES
INDICATE NOT
CHARGING
SAFETY TIMER ^NO
AT EOC?
YES
STOP CHARGING
INDICATE NOT
CHARGING
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For more information www.linear.com/LTC4020
ENABLE IDEAL DIODE
FUNCTION
NO
V_FB = 2.4375?
YES
4020 CD01
4020fb