Linear Technology 1317A-D Quick Start Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A-D
ACTIVE RESET ISOLATED 18-72V INPUT TO 24V @5A DC/DC POWER CONVERTER
DESCRIPTION
Demonstration circuit 1317A-D is isolated input to
high current output 1/8th Brick footprint converter
featuring the LT ® 1952 switching controller with Ac-
tive Reset circuit. The Active Reset circuit can im-
prove the efficiency in wide input voltage applica-
tions. Also, the Active Reset allows the implementa-
tion of self-driven synchronous secondary rectifiers
in some applications.
The DC1317A-D (Figure 7) converts isolated 18V to
72V input to 24V output and provides over 5A of out-
put current depending on cooling. When determining
the cooling requirements the actual input voltage
range and continuous maximum output current must
be taken into account. The converter operates at
220kHz with the peak efficiency greater than 94%.
The DC1317 can be easily modified to generate out-
put voltages in the range from 0.6V to 48V. The out-
put currents are limited by total output power of up to
150W.
The available versions of DC1317A are:
DC1317A-A, 34-75Vin to 3.3V, 35A
DC1317A-B, 18-72Vin to 5V, 25A
DC1317A-C, 18-72Vin to 12V, 8A-12A
DC1317A-D, 18-72Vin to 24V, 5A
DC1317A-E, 36-72Vin to 5V, 12A
Table 1. Performance Summary
PARAMETER
Minimum Input Voltage
Maximum Input Voltage
V OUT
Typical Output Ripple V OUT
Nominal Switching Frequency
DC1317A-F, 9-36Vin to 3.3V, 22A
* DC1317A-F5, 9-36Vin to 5V, 20A
DC1317A-G, 9-36Vin to 12V, 8A
* DC1317A-G18, 9-36Vin to 18V, 5A
DC1317A-H, 9-36Vin to 48V, 1.5A
* The *DC1317A-G18 is a slightly modified design
featuring 18V @6A output. Please contact the LTC
factory for details.
The DC1317 circuit features soft-start which prevents
output voltage overshoot on startup or when recover-
ing from overload condition.
The DC1317 has precise over-current protection cir-
cuit that allows for continuous operation under short
circuit conditions. The low power dissipation under
short circuit conditions insures high reliability even
during short circuits.
The LT1952 can be synchronized to an external clock
of up to 400kHz. Please refer to LT1952 data sheet for
design details and applications information.
Design files for this circuit board are available. Call
the LTC factory.
LT is a trademark of Linear Technology Corporation
CONDITION
I OUT = 0A to 5A
I OUT = 0A to 5A
V IN = 18V to72V, I OUT = 0A to 5A (7Amax)
V IN = 18V to 72V, I OUT = 0A to 5A
LT1952-1
VALUE
18V
72V
24V ±3%
100mV P–P
220kHz
1