LTC3625-1_15 Datasheet, PDF (7/16 Pages) Linear Technology – 1A High Efficiency 2-Cell Supercapacitor Charger with Automatic Cell Balancing

LTC3625/LTC3625-1
Pin Functions
V_MID (Pin 10): Midpoint of Two Series Supercapacitors.
The pin voltage is monitored and used, along with V_OUT ,
to enable or shut down the buck and boost converters
during charging to achieve voltage balancing of the top
and bottom supercapacitors.
V_OUT (Pin 11): Output Voltage Pin. Connect V_OUT to the
positive terminal of the top supercapacitor. The pin volt-
age is monitored and used, along with V_MID, to enable or
shut down the buck and boost converters during charg-
ing to achieve voltage balancing of the top and bottom
supercapacitors.
SW2 (Pin 12): Switch Pin for the Boost Regulator. External
inductor connects between the SW2 pin and V_MID. If CTL
is logic high, then SW2 must be connected to SW1.
GND (Exposed Pad Pin 13): Ground. The exposed pad
must be connected to a continuous ground plane on
the printed circuit board directly under the LTC3625/
LTC3625‑1 for electrical contact and to achieve rated
thermal performance.
Block Diagram
PFI
7
8 ^PFO
1.20V
BOOST REGULATOR
9 ^PGOOD
4.44V/4.90V (LTC3625)
3.7V/4.16V (LTC3625-1)
SD_BOOST
2A AVG
INPUT CURRENT
SYNCHRONOUS
BOOST CURRENT
REGULATOR
V_OUT
11
D
SW2
12
C
V_SEL
4
V_MID
10
THRESHOLD
DETECTOR
EN
5
CTL
3
MASTER
LOGIC
PROG
6
OVERTEMPERATURE
SHUTDOWN
V_IN
V_OUT
V_MAXER
BUCK REGULATOR
V_{MID_GOOD}
SD_BUCK
REF/R PROGRAMMED
AVG OUTPUT CURRENT
A
SYNCHRONOUS
BUCK CURRENT
REGULATOR
B
1.2V
+
–
V_IN
2
SW1
1
GND
13
3625 BD
3625f