ZHCSLW9 November 2022 ISOW7741-Q1 , ISOW7742-Q1
PRODUCTION DATA
The integrated isolated DC-DC converter uses advanced circuit and on-chip layout techniques to reduce radiated emissions and achieve upto 46% typical efficiency. The integrated transformer uses thin film polymer as the insulation barrier. Output voltage of power converter can be controlled to 3.3 V or 5 V using VSEL pin. The DC-DC converter can be switched off using the EN/FLT pin to save power. The output voltage, VISOOUT , is monitored and feedback information is conveyed to the primary side through a dedicated isolation channel. VISOOUT needs to be connected to VISOIN to ensure the feedback channel is properly powered to regulate the DC-DC converter. This can be achieved by connecting the pins directly or through an LDO that remains powered up at all times. A ferrite bead is recommended between Visoout and Visoin to further reduce emissions. See the Section 10.2 section. The duty cycle of the primary switching stage is adjusted accordingly. The fast feedback control loop of the power converter ensures low overshoots and undershoots during load transients. Undervoltage lockout (UVLO) with hysteresis is integrated on the VIO, VDD and VISOIN supplies which ensures robust fails-safe system performance under noisy conditions. An integrated soft-start mechanism ensures controlled inrush current and avoids any overshoot on the output during power up.