LT1680 Datasheet, PDF (1/16 Pages) Linear Technology – High Power DC/DC Step-Up Controller

LT1680
High Power DC/DC
Step-Up Controller
FEATURES
s _{High Voltage: Operation Up to 60V Max}
s _{High Current: N-Channel Drive Handles Up to}
10,000pF Gate Capacitance
s _{Programmable Average Current Limiting}
s _{5V Reference Output with 10mA External}
Loading Capability
s _{Fixed Frequency Current Mode Operation}
s _{Oscillator Synchronizable Up to 200kHz}
s _{Undervoltage Lockout with Hysteresis}
s _{Programmable Start Inhibit for Power Supply}
Sequencing and Protection
s _{User Adjustable Slope Compensation}
U
APPLICATIONS
s _{High Power Single Board Systems}
s _{Distributed Power Converters}
s _{Industrial Control Systems}
s _{Lead-Acid Battery Back-Up Systems}
s _{Automotive and Heavy Equipment}
DESCRIPTION
The LT^®1680 is a high power, current mode switching
power supply controller optimized for boost topologies.
The IC drives N-channel MOSFET switches for DC/DC
converters in applications up to 60V input. A high current
gate drive output handles up to 10,000pF gate capaci-
tance, enabling the construction of high power DC/DC
converters. Current sense common mode range up to 60V
allows current sensing to be referenced to the input
supply, eliminating the need for sense blanking circuits.
The LT1680 incorporates programmable average current
limiting allowing accurate limiting of DC current in the
magnetics, independent of ripple current . User adjustable
slope compensation provides stable operation at duty
cycles up to 90%.
The LT1680 operating frequency is programmable and
can be synchronized up to 200kHz. Minimum off-time
operation provides switch protection. The IC also incorpo-
rates a soft start feature that is gated by both shutdown
and undervoltage lockout conditions.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
12V to 48V, 250W Boost
C2
1µF
R_CT
C_CT
15k
1nF
C3 2.2nF
C4 0.22µF
C_VC 4.7nF ^1N914
R_VC 4.7k
R7
C6 0.1µF
2k
12V_IN
10V TO 15V
24A (DC)
R_SENSE
0.005Ω
LT1680
1
SL/ADJ
2
C_T
3
I_AVG
4
SS
16
5V_REF
15
SYNC
14
12V_IN
13
GATE
5
12
V_C
6
PGND
11
R9
SGND RUN/SHDN
100k
7
V_FB
8
V_REF
SENSE ^{– 10}
SENSE ^{+ 9}
R6
75k
+ ^CIN
680µF
25V
×4
+
C12
1µF
L1
25µH
M1
IRFZ44
×3
MBR0520
C11 1nF
D1
MBR20100CT
×2
+
L1: Kool Mµ^®, 18T #14 ON 77314-A7
Kool Mµ IS A REGISTERED TRADEMARK OF MAGNETICS, INC.
V_OUT
48V
C_{OUT 5.2A}
680µF
63V
×3
1680 TA01
Efficiency vs Output Power
100
V_OUT = 48V
95
90
85
80
75
0
50 100 150 200 250
OUTPUT POWER (W)
1680 TA02
1