SMPS controller. MD1801 Datasheet
High performance primary side regulator (PSR) offline switch
power supply (SMPS) controller
MD180X is high performance primary sensing regulator (PSR) and monolithic switch power controller which is designed for
small-power supply equipment with current mode control. Built-in accurate CV/CC control circuit, eliminates optocoupler, TL431
and its related loop devices. High integration design, a high performance power BJT and PFM controller and all kinds of
protection circuits in one chip, to minimize the peripheral components to save the cost greatly.
MD180X can be simply designed a typical flyback switch converter, the unique driving technology promotes the characteristics
of withstand voltage and achieves excellent converting efficiency.
◆ Built-in 700V@MD1800; 810V@MD1801 power BJT.
◆ PSR control, eliminates optocoupler and TL431
◆ Accurate CV/CC control
◆ Hysteresis over-temperature protection (OTP) circuit
◆ Higher efficiency and meet Level 6 efficiency standards
◆ Output voltage protection (OVP/UVP)
◆ < 100 mW no-load consumption
◆ Auto-Restart function
◆ Ultra-low start-up current
◆ Good EMC characteristic allows the simple EMC circuit
◆ Intelligent mobile phone/small size tablet computer
◆ Digital cameras and other small digital products
◆ Power adapters for network products etc.
◆ RCC solutions Replace.
S Packge(SOIC-7 )
Output Power Table
MD1800 S 4W
MD1801 S 5W
1. Continuous maximum output power is tested in typical non-ventilated closed adapter
measured at environment temperature + 40 ℃.
2. The biggest actual continuous output power is tested in the condition of that peripheral
circuit is designed properly and enough space for heat dissipation.
◆ Package: S: SOP - 7; P: DIP-8
Output CC/CV VI Characteristic
PIN Function Description
Conntect external primary current sensing resistor RCS, the controller can detect the
CS primary current through the external sens resistor. When the voltage on the resistor
achieves the maximum value, the internal power BJT will be turn off immediately.
to connect with a 100+nf capacitor, the pin will become output cable drop
Power supplying pin of the controller, In order to let the controller gain more stable
supply voltage, the external filter capacitor must use low equivalent impedance (Low
ESR) of the electrolytic capacitor.
Output feedback pin, to detect the output condition through the auxiliary winding voltage
of the transformer.
To connect the collector of internal power BJT
The referring grounding pin of the controller
FUNCTIONAL BlOCK DIAGRAM