Xysemi XR2201 Schematic [ru]
XR2201
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1.2MHZ，26V Step-up DC/DC Converter
GENERAL DESCRIPTION
The XR2201 is a high frequency, high
efficiency DC to DC converter with an
integrated 2.8A, 0.1Ω power switch
capable of providing an output voltage up
to 26V. The fixed 1.2MHz allows the use
of small external inductions and
capacitors and provides fast transient
response. It integrates Soft start, Comp,.
only need few components outside.
FEATURES
z 2.3V to 6V input voltage Rangel
z Efficiency up to 96%
z 26V Boost converter with 2.8A switch
current
z 1.2Mhz fixed Switching Frequency
z Integrated soft-start
z Thermal Shutdown
z Under voltage Lockout
z ESD 8KV Pass( HBM )
z 8-Pin MSOP Package
APPLICATIONS
• Handheld Devices
• GPS Receiver
• Digital Still Camera
• Portable Applications
• DSL Modem
• PCMCIA Card
• TFT LCD Bias Supply
Figure 1. Typical Application Circuit
XySemi Inc - 1 - www.xysemi.com
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XR2201
A
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ORDERING INFORMATION
PART
NUMBER
XR2201 -40°C to 85°C 1.2MHZ
TEMP RANGE
SWICHING
FREQUENCY
OUTPUT
VOLTAGE (V)
DJ 2.8 MSOP 8
ILIM (A) PACKAGE PINS
PIN CONFIGURATION
Figure 2. PIN Configuration
PIN DESCRIPTION
PIN
NUMBER
1 NC Not use
2 FB Feedback pin
3 EN Shutdown control input., Connect this pin to logic high level to enable the device
4 PGND Power ground
5 SW Switch pin
6 IN Input power supply pin
7 NC Not use
8 NC Not use
PIN
NAME
PIN DESCRIPTION
ABSOLUTE MAXIMUM RATINGS
(Note: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating
conditions for long periods may affect device reliability.)
PARAMETER VALUE UNIT
Supply Voltage VIN -0.3 to 6.5 V
FB, EN Voltage -0.3 to VIN+0.3 V
SW Voltage Vin+0.3 to 28V V
Operating Ambient Temperature
Maximum Junction Temperature 150 °C
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-40 to 85 °C
XR2201
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Storage Temperature -55 to 150 °C
Lead Temperature (Soldering, 10 sec) 300 °C
ELECTRICAL CHARACTERISTICS
(VIN = 3.6V, TA= 25°C unless otherwise specified)
PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT
Input Voltage Range V
2.3 6.0 V
IN
Boost output voltage range Vout 26 V
UVLO Threshold
V
Operating Supply Current
I
SUPPLY
Shutdown Supply Current
Regulated Feedback Voltage V
Peak Inductor Current I
Oscillator Frequency F
UVLO
FB
PEAK
OSC
V
HYSTERESIS
=1.3V，EN=Vin, I
V
FB
=100mV
Load
=0
VEN =0V, VIN =4.2V 0.1 1
1.188 1.2 1.212 V
2.5 2.8 3.0 A
0.9 1.2 1.5 MHz
2.1
2.2
2.3 V
75 135
µA
Rds(ON) of N-channel FET ISW =-100mA 0.1 0.2 Ohm
Enable Threshold VIN = 2.3V to 5.5V 0.3 1 1.5 V
Enable Leakage Current -0.1 0.1 µA
SW Leakage Current
VEN = 0V, VSW = 0V or 5V, VIN = 5V
1 uA
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XR2201
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Figure 3. Functional Block Diagram
FUNCTIONAL DESCRIPTION
NORMAL OPERATION
The boost converter is designed for output
voltage up to 26V with a switch peak current limit of
2.8 A. The device, which operates in a current
mode scheme with quasi-constant frequency, is
externally 1.2MHZ and the minimum input voltage is
2.3 V. To control the inrush current at start-up a softstart pin is available.
During the on-time, the voltage across the
inductor causes the current in it to rise. When the
current reaches a threshold value set by the internal
GM amplifier, the power transistor is turned off, the
energy stored into the inductor is then released and
the current flows through the Schottky diode
towards the output of the boost converter. The offtime is fixed for a certain Vin and Vs, and therefore
maintains the same frequency when varying these
parameters.
drop across the Rdson of the power transistor
which will have an effect on the voltage across the
inductor and thus on
Some slight frequency changes might also appear
with a fixed output load due to the fact that the
output voltage Vs is not sensed directly but via the
SW Pin, which affects accuracy.
Because of the quasi-constant frequency
behavior of the device , the XR2201 eliminates the
need for an internal oscillator and slope
compensation, which provides better stability for the
system over a wide of input and output voltages
range, and more stable and accurate current
limiting operation compared to boost converters
operating with a conventional PWM scheme .The
XR2201 topology has also the benefits of providing
very good load and line regulations, and excellent
load transient response.
T (
T remains fixed).
on
off
However, for different output loads, the
frequency may slightly change due to the voltage
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