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PowTech |
PT2201
Current Mode PWM Controller
GENERAL DESCRIPTION
PT2201 is a highly integrated current mode PWM controller,
with the features of extreme low start up current, low
operating current plus green mode operation and built-in
protection functions allows the design of SMPS become
easier to meet the high performance, high reliability and low
standby power requirements.
The start-up current is very small typically 3uA so that a large
start up resistor can be used in the start-up circuit to minimize
standby power. Under the light load or no load conditions the
PT2201 automatically decreases PWM frequency and enters
burst mode operation thus the power loss on power MOSFET
is reduced. With a programmable oscillator the PWM
frequency is easily set via an external resistor.
Synchronized slope compensation has been implemented in
the PT2201 to avoid potential sub harmonic oscillation caused
by peak current control mode when operating under
Continuous Conduct Mode. Moreover, the internal LEB on
the current sense input removes the signal glitch due to
snubber circuit diode reverse recovery and greatly reduces the
external component count and system cost in the design.
The PT2201 also features multi-level protections to enhance
SMPS reliability including cycle by cycle Over Current
Protection, Over Load Protection, programmable Over
Temperature Protection, Over Voltage Protection on VDD
and VDD Under Voltage Lock-out. The gate drive output is
clamped at 18V to protect the power MOSFET. The burst
mode frequency is limited above 20 KHz thus the potential
audible noise is avoid while the system is under light or no
load conditions.
The PT2201 is available in SOP8 and DIP8 packages.
FEATURES
z Frequency Jittering For Better EMI Performance
z Frequency automatically decrease to minimize standby
power
z Noise Free Operation
z Programmable PWM Frequency
z Current Mode Operation, Built-in Slope Compensation
z Low Start-up Current
z Constant Power Limit For Universal AC Input
z Leading Edge Blanking on Current Sense
z Gate Output 18V Clamp
z Protection Functions:
Auto Recovery Programmable Over Temperature
Protection(OTP)
Auto Recovery Over Voltage Protection on VDD
(OVP) and UVLO
Line Compensated Cycle By Cycle Current Limit
(OCP)
Locked Over Load Protection (OLP)
APPLICATIONS
z Open-frame SMPS
z Fly-back Switching Power Supplier
z Power Adaptor
z Battery Charger
ORDERING INFORMATION
PACKAGE
SOP-8
TEMPERATURE
RANGE
-40℃ to 85℃
ORDERING PART NUMBER
PT2201BSOH
DIP-8
-40℃ to 85℃
PT2201BDIH
Note:
xxxxxX
Assembly Factory Code
Lot Number
TRANSPORT
MEDIA
Tape and Reel
Tube
MARKING
PT2201
xxxxxX
PT2201
xxxxxX
PT2201_DS_EN2.0
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TYPICAL APPLICATION CIRCUIT
EMI
AC in Filter
PT2201
Current Mode PWM Controller
DC out
VIN
RT
VDD
GATE
RI PT2201
FB SENSE
NTC
GND
PIN ASSIGNMENT
TL431
PIN DESCRIPTIONS
PIN PIN
No. NAMES
DESCRIPTION
1 GND Ground
2
FB
Feedback input pin. PWM duty cycle is determined by voltage level into this pin and
SENSE pin voltage level.
3 VIN Rectified line input for startup and line voltage sensing
4
RI
Internal Oscillator frequency setting pin. A resistor connected between RI and GND sets
the PWM frequency.
5 RT Temperature sensing input pin, connecting to an NTC resistor
6 SENSE Current sense input pin. Connected to MOSFET current sensing resistor node.
7 VDD DC power supply pin.
8 GATE Totem-pole gate drive output for power MOSFET.
PT2201_DS_EN2.0 Tel: 0755-8398 3377 / 135 9011 2223 http://www.gofotech.com
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