SIP11205 Datasheet, PDF (1/21 Pages) Vishay Siliconix – Feed-Forward Controller with Primary MOSFET Drivers for Intermediate Bus Converters

SiP11205
Vishay Siliconix
Feed-Forward Controller with Primary MOSFET
Drivers for Intermediate Bus Converters
DESCRIPTION
SiP11205 is a feed-forward controller for the primary side of
a half-bridge intermediate bus converter (IBC). It is ideally
suited for isolated applications such as telecom, data
communications and other products requiring an IBC
architecture and conversion of standard bus voltages such
as 48 V to a lower intermediate voltage, where high
efficiency is required at low output voltages (24 V, 12 V, 9 V
or 5 V).
Designed to operate within the telecom voltage range of
36 V to 75 V and withstand 100 V transients for a period of
100 ms, the IC is designed for controlling and driving both
the low- and high-side switching devices of a half-bridge
converter.
The feed-forward feature is designed to make the converter
output semi-regulated and is beneficial for point-of-load
applications that require narrow input range. SiP11205 has
advanced current monitoring and control circuitry, which
allows the user to set the maximum current in the primary
circuit. This feature acts as protection against overcurrent
and output short circuit. Current sensing is by means of a
sense resistor connected in series with the primary low-side
MOSFET.
TYPICAL APPLICATION CIRCUIT
Vin+
42 V to 55 V
100 V/100 ms
Vin-
1
VINDET
2
VIN
3
VCC
4
COMP
5
CS
6
AGND
7
VREF
8
ROSC
SiP11205
16
BST
15
DH
14
LX
13
DL
12
PGND
11
SS
10
RDB
9
COSC
FEATURES
• 36 V to 75 V input voltage range
• Withstand 100 V, 100 ms transient capability
• Integrated ± 1.6 A typical high- and low-side MOSFET
drivers
• Oscillator frequency is programmable from 200 kHz to
1 MHz (100 kHz to 500 kHz switching frequency) and can
be externally synchronized
• Voltage feed-forward compensation
• High voltage pre-regulator operates during start-up
• Current sensing on primary low-side switch
• Hiccup mode
• System low input voltage detection
• Chip UVLO function
• Programmable soft-start function
• Over temperature protection (160 °C)
• Greater than 95.5 % efficiency for 42 V to 55 V input range
• Better than 2 % line regulation at 9 A
APPLICATIONS
• Intermediate bus architectures
• Telecom and Datacom
• Routers and servers
• Storage area network
• Base station
• 1/8 and 1/4 bricks
Vo+
Vo-
Document Number: 69233
S-81795-Rev. C, 04-Aug-08
www.vishay.com
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