SG6742MR_ML

The highly integrated SG6742MR_ML/MR PWM controller provides several features to enhance the performance of flyback converters.

To minimize standby power consumption, a proprietary green-mode function provides off-time modulation to linearly decrease the switching frequency at light-load conditions.To avoid acoustic-noise problems, the minimum PWM frequency is set above 22KHz. The green-mode function enables the power supply to meet international power conservation requirements.With the internal high-voltage startup circuitry, the power loss due to bleeding resistors is also eliminated. To further reduce power consumption, SG6742MR_ML/MR is manufactured using the BiCMOSprocess, which allows an operating current of only 2.7mA.

SG6742MR_ML/MR integrates a frequency-hopping function that helps reduce EMI emission of a power supply with minimum line filters. SG6742MR_ML's built-in synchronized slope compensation achievesstable peak-current-mode control. The proprietary, internal line compensation ensures constant output power limit over a wide AC input voltage range, from 90V_AC to 264V_AC.

SG6742MR_ML/MR provides many protection functions. In addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety should an open-loop or outputshort-circuit failure occur. PWM output is disabled until V_DD drops below the UVLO lower limit, when the controller starts up again. As long as V_DD exceeds ~26V, the internal OVPcircuit is triggered.

SG6742MR_ML/MR is available in an 8-pin SOP package.