MP174 400mA Non-Isolated Off-Line Regulator TSOT23

MP174 400mA Non-Isolated Off-Line Regulator TSOT23

MP174 is a primary-side regulator that provides accurate constant voltage (CV) regulation without opto-coupler.

Key Specifications

Features

• Primary-side CV control, supporting Buck, Buck-Boost, Boost and Flyback topologies
• Integrated 700V/13.5Ω MOSFET and current source
• <30mW no-load power consumption
• Up to 5W output power
• Maximum DCM output current less than 250mA
• Maximum CCM output current less than 400mA
• Low VCC Operating Current
• Frequency foldback
• Limited maximum frequency
• Peak-current compression

Typical Application Circuit

Applications

• Home appliances, white goods and consumer electronics
• Industrial controls

Design Notes

• The PFC inductor must support the maximum duty cycle at the lowest line voltage, which is where saturation risk peaks.
• High-voltage startup and X-capacitor discharge paths dominate no-load standby loss; verify them against the efficiency target.
• Leakage inductance and the RCD clamp set the turn-off loss — snubber values are a thermal trade-off, not a fixed recipe.
• Synchronous rectification timing must track the primary switching; a mistimed SR FET conducts through its body diode and fails hot.

Common Questions