DESCRIPTION

SD6834 is current mode PWM+PFM controller with built-in high-voltage

MOSFET used for SMPS.

It features low standby power and low start current. In standby mode, the

circuit enters burst mode to reduce the standby power dissipation.

The switch frequency is 25~67KHz decided by the load with jitter

frequency for low EMI.

Built-in peak current compensation circuit makes the limit peak current

stable even with different input AC voltage. Maximum peak current

compensation during power-on reduces pressure on transformer to avoid

saturation, the peak current compensation will decrease for balance after

power-on. Limit output current can be adjusted through the resistor

connected to CS.

It integrates various protections such as undervoltage lockout, overvoltage

protection, overload protection, leading edge blanking, primary winding

overcurrent protection and thermal shutdown. The circuit will restart until

normal if protection occurs.

FEATURES

 Energy Star 2.0 standard

 Lower start-up current (3μA)

 Various switching frequency following load for the high efficiency

 EMI Frequency jitter for low EMI

 Overvoltage, primary winding overcurrent, overload and over

temperature protections

 External peak current sense resistor

 Undervoltage lockout

 Built-in high voltage MOSFET

 Auto restart mode

 Peak current compensation Maximum peak current

compensation for initialization to realize the soft start function.

 Burst mode

 Cycle by cycle current limit