|
|
PDF LT1680CN Data sheet ( Hoja de datos )
| Número de pieza | LT1680CN | |
| Descripción | High Power DC/DC Step-Up Controller | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT1680CN (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
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
RCT
CCT 15k
1nF
C3 2.2nF
C4 0.22µF
CVC 4.7nF 1N914
RVC 4.7k
C6 0.1µF
R7
2k
12VIN
10V TO 15V
24A (DC)
RSENSE
0.005Ω
LT1680
1
SL/ADJ
2
CT
3
IAVG
4
SS
5VREF
SYNC
12VIN
GATE
16
15
14
13
5 12
VC PGND
6 11
SGND RUN/SHDN
R9
100k
7
VFB
8
VREF
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.
+
VOUT
48V
COUT 5.2A
680µF
63V
× 3 1680 TA01
Efficiency vs Output Power
100
VOUT = 48V
95
90
85
80
75
0
50 100 150 200
OUTPUT POWER (W)
250
1680 TA02
1
1 page  
TYPICAL PERFORMANCE CHARACTERISTICS
LT1680
Error Amplifier Source Current
vs Temperature
350
325
300
275
250
225
200
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G10
RUN/SHDN Threshold Hysteresis
vs Temperature
14
13
12
11
10
9
8
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G13
Sense Amplifier Input Bias
Current (Source) vs Temperature
1200
1100
VCMSENSE = 0V
1000
900
800
700
600
500
400
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G16
SS Output Current
vs Temperature
9
8
7
6
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G11
Average Current Limit Threshold
Sense Voltage vs Common Mode
Voltage
160
FULL OPERATING
150 TEMPERATURE RANGE
140
UPPER LIMIT
130
TYPICAL
120
LOWER LIMIT
110
100
90
80
0 12345
VSENSE(CM) (V)
60
1680 G14
Sense Amplifier Input Bias
Current (Sink) vs Temperature
60
VCMSENSE = 10V
55
50
45
40
35
30
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G17
RUN/SHDN Rising Threshold
vs Temperature
1.26
1.25
1.24
1.23
1.22
1.21
1.20
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G12
UVLO Thresholds vs Temperature
10.00
9.75
9.50 RISING
9.25
9.00 FALLING
8.75
8.50
8.25
8.00
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
1680 G15
RUN/SHDN Input Current
vs Pin Voltage
800
FULL OPERATING
700 TEMPERATURE
RANGE
600
500
400
UPPER
TYPICAL
LIMIT
300
200
LOWER
100 LIMIT
0
0 0.5 1.0 (1.25) 1.5 2.0
RUN/SHDN PIN VOLTAGE (V)
1680 G18
5
5 Page 
LT1680
APPLICATIONS INFORMATION
additional current can be minimized by making the con-
nection through an external resistor (100k is typically used).
When shutting down the LT1680, the RUN/SHDN pin volt-
age must remain between the shutdown threshold (~1.13V)
and a minimum shutdown control limit voltage (see Fig-
ure 4) for a least 25µs. If a digital input or fast moving
clamp is used, this can be achieved by forcing a shutdown
control voltage above the minimum limit or by using a
simple integrator to increase the fall time of the input sig-
nal. A single pole integrator stage must have a
τ ≥ (7)(10 –5).
800
700
600
500
– 40 – 20 0 20 40 60
TEMPERATURE (°C)
80
1680 F04
Figure 4. Minimum Shutdown Control Limit vs Temperature
Figure 5 is an example of a digital control input clamp. A
logic high signal pulls the RUN/SHDN pin above its turn-
on threshold through the diode. When a shutdown (logic
low) signal is received, the RUN/SHDN pin is forced to
0.95V via the resistor divider until shutdown is fully estab-
lished and the 5VREF voltage collapses.
1N914
DIGITAL
INPUT
R1
43k
R2
10k
5VREF
LT1680
RUN/SHDN
1680 F05
Figure 5. Digital Input Shutdown Level Control
Figure 6 is an example of a digital control integration stage
at the RUN/SHDN input. The integrator has a τ = (10)(103)
• (10)(10–9) = (1.0)(10–4). This circuit technique, however,
delays initiation of controller shutdown about 125µs from
the reception of the shutdown signal (5V – 0V transition).
DIGITAL
INPUT
R1
10k
RUN/SHDN
C1
10nF
LT1680
1680 F06
Figure 6. Digital Input Shutdown Integration Control
Figure 7 is an example of an integrator stage coupled with
a 24V input power supply sequencing circuit similar to that
shown in Figure 3. The integrator stage allows use of an
active shutdown clamp for implementation of both user-
controlled shutdown and input power supply sequencing
protection.
R1
VIN 160k
24V
R3
390k
R4
10k
SHDN
R2
10k
5VREF
LT1680
RUN/SHDN
C1
10nF
1680 F07
Figure 7. Input Supply Sequencing with
User-Controlled Shutdown
Oscillator Synchronization
The LT1680 oscillator generates a modified sawtooth
waveform at the CT pin between low and high thresholds
of 0.8V (vl) and 2.5V (vh) respectively. The oscillator can
be synchronized by driving a TTL level pulse into the SYNC
pin. This pin connects to a one shot circuit that reduces the
oscillator high threshold to 2V for about 200ns. The SYNC
input signal should have minimum on/off times of ≥1µs.
SYNC
2.5V (vh)
2V
VCT
0.8V
FREE RUN
SYNCHRONIZED
(vl)
1680 F08
Figure 8. Free Run and Synchronized Oscillator
Waveforms (at CT Pin)
Inductor Selection
The inductor for an LT1680 converter is selected based on
output power, operating frequency and efficiency require-
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LT1680CN.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT1680C | High Power DC/DC Step-Up Controller | Linear Technology |
| LT1680CN | High Power DC/DC Step-Up Controller | Linear Technology |
| LT1680CSW | High Power DC/DC Step-Up Controller | Linear Technology |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |