75W以下电流模式PWM反激式控制器, 支持 OCP、OTP、UVLO和OVP

PT2201_DS_EN2.3 PT2201 GENERAL DESCRIPTION
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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 lo ad or no load conditions the PT2201 automatically decrease s 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 compensati on has been implemented in the PT2201 to avoid potential sub harmonic oscillation caused by peak current control mode when operating under Continuous Conduct Mode. Moreove r, the internal LEB on the current sense input removes the signal glitch due to snubber circuit diode reverse rec overy 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, Ov er Voltage Protection on VDD and VDD Under Voltage Lock-out . The gate drive output is clamped at 18V to protect th e power MOSFET. The    burst mode frequency is lim ited above 20 KHz thus the potential audible noise is avoid while th e system is under light or no load conditions. The PT2201 is available in SOP8 and DIP8 packages. FEATURES z Frequency Jittering For Be tter EMI Performance z Frequency automatically decr ease to minimize standby power z Noise Free Operation z Programmable PWM Frequency z Current Mode Operation, Bu ilt-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) z RoHS compliant APPLICATIONS z Open-frame SMPS z Fly-back Switchi ng Power Supplier z Power Adaptor z Battery Charger  
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