Low Voltage Start-Up Controller For 4-85V Input DC/DC Power Supply


MORNSUN’s SCM9603B has a built-in 85V high voltage transistor which works over a wide input voltage range from 4VDC to 85VDC and is suitable for wide input voltage DC/DC power supply.

When the VDD voltage is less than 8V, the chip begins to charge the VDD pin bypass capacitance. And Large bypass capacitor charge current is up to 20mA when input/output voltage delta is 1V.When the VDD voltage exceeds 10V, the chip stops charging the VDD pin bypass capacitor. At this time, power is supplied by the auxiliary winding and the chip’s working current is reduced to 150uA. After the controller start-up, the SCM9603B will continue to work for a certain period of time, which is beneficial to improve the capacitive ability of the power supply.
Moreover, the SCM9603B has built-in over-temperature protection which improves its reliability.

Key Features

  • Wide input voltage range, 4VDC to 85VDC
  • Small SOT-23 package, benefits a low-cost design
  • Large bypass capacitor charge current, up to 20mA (input/output voltage delta 1V)
  • Output charge current >2mA at low input voltage (4V)
  • Adjustable start-up time set by VDD bypass capacitor
  • With VVDD output voltage >10V, starter IC is off and with VVDD output voltage <8V, IC restarts.
  • Built-in Over-temperature protection

35-350W Enclosed AC/DC Switching Power Supplies for Industrial Control and IoT


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