GENERAL DESCRIPTION
PT2202 is a highly integrated current mode PWM controller ， providing low standby power and cost effective system solution for the sub 30W flyback converter applications. PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load condition, the IC enters ‘Green Mode’ operation to minimize switching loss and low standby power and high efficiency is thus achieved. PT2202 also features low VDD startup current which also contributes to low standby power. The built in LEB on the current sense input removes the signal glitch due to snubber circuit diode reverse recovery and will greatly reduce the external component count and system cost in the design.
Rich protection is implemented in PT2202 including cycle-by-cycle current limiting (OCP), over load protection (OLP), VDD over voltage clamp and under voltage lockout (UVLO). Gate drive output is clamped at 18V to protect the power MOSFET. By limiting the minimum frequency above 22 kHz eliminates the potential audible noise when the system works under light or no load conditions.
Excellent EMI performance is achieved with C.R.PowTech proprietary frequency Jittering technique together with soft driving control at totem pole gate drive output.
The PT2202 is available in SOT23-6, SOP-8 and DIP-8 packages.
FEATURES
l Frequency Jittering for Improved EMI Performance
l Green-Mode PWM for Improved Efficiency and Minimum standby power design
l Low start up current 20uA ( Typ. 3uA) and Low operation current 2mA (Typ. 1mA)
l Current mode operation
l Leading-edge blanking on current sense input
l Programmable PWM frequency
l Constant output power limit for universal AC input
l Built-in power limit control (OLP)
l Cycle-by-cycle current limiting (OCP)
l Under voltage lockout (UVLO)
l GATE output maximum voltage clamped at 18V
l Totem pole output includes soft driving for better EMI
APPLICATIONS
Offline AC/DC flyback converter for
l Power Adapter
l Open-frame SMPS
l Battery Charger Adapter
PDF文档下载