LTC3725 Datasheet, PDF (4/20 Pages) Linear Technology – Single-Switch Forward Controller and Gate Driver

LTC3725
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs V_CC
2.0
TRICKLE CHARGER
1.5
LINEAR REGULATOR
1.0
0.5
0
0
5
10
15
V_CC (V)
3725 G01
Oscillator Frequency
f_OSC vs R_FSET
800
700
600
500
400
300
SECONDARY-SIDE CONTROL
200
100
PRIMARY-SIDE CONTROL
0
0
100
200
300
400
R_FSET (kΩ)
3725 G04
Shunt Regulator Current vs
Temperature
25
24
23
22
21
20
19
18
17
16
15
–60 –40 –20 0 20 40 60 80 100
TEMPERATURE (°C)
3725 G07
UVLO Voltage Threshold vs
Temperature
1.245
1.240
V_UVLOR
1.235
1.230
1.225
V_UVLOF
1.220
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3725 G02
Oscillator Frequency vs
Temperature
203
202
201
PRIMARY-SIDE CONTROL
200
R_FS(P) = 100kΩ
199
198
197
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3725 G05
V_GDUV vs Temperature
14
13
V_CC RISING (TRICKLE CHARGER)
12
11
10
9
8
V_CC RISING (LINEAR REGULATOR)
7
V_CC FALLING (BOTH)
6
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3725 G08
4
UVLO Hysteresis Current vs
Temperature
5.05
5.00
4.95
4.90
4.85
4.80
–60 –40 –20 0 20 40 60
TEMPERATURE (°C)
80 100
3725 G03
Shunt Regulator Current I_CC
vs V_CC
18
15
12
9
6
3
0
14.00
14.25
14.50
V_CC (V)
14.75 15.00
3725 G06
Optoisolator Bias V_FB/IN+ vs
I_FB/IN+
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
0.5
1.0
1.5
2.0
–I_FB/IN+ (mA)
3725 G09
3725f