LTC3226_12 Datasheet, PDF (6/16 Pages) Linear Technology – 2-Cell Supercapacitor Charger

LTC3226
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C, unless otherwise noted.
Leakage Balancer Source and
Sink Capability
12
V_IN = 3.3V, V_CPO = 5V
10 VMID SHUNT REG OFF
8
VMID
6
SOURCING
CURRENT
4
2
0
90°C
25°C
–45°C
–2
–4
VMID
SINKING
–6
CURRENT
–8
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
VMID VOLTAGE (V)
3226 G10
VMID Shunt Regulator Voltage
vs Current and Temperature
2.70
ONLY LEAKAGE
BALANCER
2.65
ACTIVE
2.60
SHUNT
REGULATOR
2.55
ACTIVE
2.50
2.45
2.40
0.1
V_IN = 3.3V
V_CPO = 5V
90°C
25°C
–45°C
1
10
100
VMID CURRENT (mA)
1000
3226 G11
Ideal Diode Gate Current
vs (V_IN-V_OUT)
5
FAST
4 _OFF
LINEAR
REGION
3
2
1
0
FAST
–1
FORWARD
ON
–2
VOLTAGE
–3
–4
–5
–100
–50
0
50
V_IN – V_OUT (mV)
100
3226 G12
Charge Profile When Top
Capacitor = Bottom Capacitor
6
Charge Profile When Top
Capacitor > Bottom Capacitor
6
5
CPO
4
V_IN
3
V_MID
2
1
0
1x
2x
MODE MODE
R_PROG = 33.2k
C_SC = 1.2F
–1
TIME (5 SECONDS/DIV)
3226 G13
5
CPO
4
V_IN
3
V_MID
2
1
2x ^{VMID CLAMPED}
MODE ^{(SHUNT ACTIVE)}
0
1x
MODE
R_PROG = 33.2k, C_SC = 1.2F
EXTRA 1.5F BETWEEN CPO
–1
AND V_MID
TIME (5 SECONDS/DIV)
3226 G14
Charge Profile When Top
Capacitor < Bottom Capacitor
6
5
CPO
4
V_IN
3
V_MID
2
TOP CAP
1
CLAMPED
R_PROG = 33.2k,
0
1x
2x
C_SC = 1.2F, EXTRA
MODE MODE ^{1.5F BETWEEN}
V_MID AND GND
–1
TIME (5 SECONDS/DIV)
3226 G15
Normal-to-Back-Up Mode
Switching Transient Waveform
4
V_OUT
3
V_IN
2
PFO
(1V/DIV)
1
0
0
100
200 300
TIME (μs)
C_SC = 1.2F
C_OUT = 47μF
I_LOAD = 2A
400 500
3226 G16
3226fa
6