CX7131 PSR-precision switching power supply chip overview CX7131 is a high precision off-line switching power supply circuit, used in low-power AC / DC charger and adapter. The maximum output power 5W, using SOP8 / DIP8 package. The use of primary sampling for accurate constant current control, eliminates the need for general application of the optocoupler and TL431. In constant current mode, the output power by CS pin external sense resistor Rs settings. Under constant pressure mode, multiple operating modes of the chip can guarantee higher overall conversion efficiency. In addition, the chip built-in cable drop compensation, thus making good load regulation. In the constant-current mode to PFM state, working in constant voltage mode PWM state, reduced frequency at light loads. Provides a power soft start function and various protection functions can be self-recovery, including by-cycle current limit protection (OCP), VDD over voltage protection (OVP), VDD over voltage clamp, undervoltage protection (UVLO), overtemperature protection and so on. CX7131 has a shake-frequency function, can provide better EMI performance. Features? 5% over the full voltage range constant voltage accuracy of 5% of the current precision? Using primary side feedback control, eliminating the need for an optocoupler and TL431? Externally set current value of the output power? Built PSR constant Flow control? built-in adaptive peak current control? built-in primary inductance compensation? externally adjust the line drop compensation (in the same proportion to raise R5 R6 resistor, improve line up)? a power soft start? built-in cutting-edge consumer Hidden (LEB) function? by-cycle current limit protection (OCP)? undervoltage protection (UVLO), overvoltage protection (OVP), VDD voltage clamping protection applications ?? phone charger ?? PDA, digital camera battery charger? ? TV, PC auxiliary power ?? alternative linear regulators, RCC Power