PRODUCT NAME

ICF CP2021

FUNCTIONAL DESCRIPTION

Current Mode PWM Controller

APPLICATIONS

Offline AC/DC flyback converter for

Battery Charger

Power Adaptor

Set-Top Box Power Supplies

Open-frame SMPS

GENERAL DESCRIPTION

ICF CP2021 is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications in sub 30W range.

PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load condition, the IC operates in extended ‘burst mode’ to minimize switching loss. Lower standby power and higher conversion efficiency is thus achieved. VDD low startup current and low operating current contribute to a reliable power on startup design with ICF CP2021. A large value resistor could thus be used in the startup circuit to minimize the standby power. The internal slope compensation improves system large signal stability and reduces the possible sub-harmonic oscillation at high PWM duty cycle output. Leading-edge blanking on current sense(CS) input removes the signal glitch due to snubber circuit diode reverse recovery and thus greatly reduces the external component count and system cost in the design.

ICF CP2021 offers complete protection coverage with automatic self-recovery feature including Cycle-by- Cycle current limiting (OCP), over load protection (OLP), VDD over voltage clamp and under voltage lockout (UVLO). The Gate-drive output is clamped to maximum 18V to protect the power MOSFET.

Excellent EMI performance is achieved with proprietary frequency shuffling technique together with soft switching control at the totem pole gate drive output.

Tone energy at below 20KHZ is minimized in the design and audio noise is eliminated during operation.

FEATURES

l Proprietary Frequency Shuffling Technology for Improved EMI Performance.

l Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design

l Audio Noise Free Operation

l External Programmable PWM Switching Frequency

l Internal Synchronized Slope Compensation

l Low VDD Startup Current and Low Operating Current (1.4mA)

l Leading Edge Blanking on Current Sense Input

l Good Protection Coverage With Auto Self-  Recovery：

Ø VDD Over Voltage Clamp and Under Voltage Lockout with Hysteresis (UVLO)

Ø Gate Output Maximum Voltage Clamp (18V)

Ø Proprietary Line Input Compensated Cycle-by-Cycle Over-current Threshold Setting For Constant Output Power Limiting Over Universal Input Voltage Range.

Ø Overload Protection (OLP)

BLOCK DIAGRAM

ORDERING INFORMATION