MP174A 400mA Non-Isolated Off-Line Regulator TSOT23

MP174A 400mA Non-Isolated Off-Line Regulator TSOT23

The MP174A is a primary-side regulator that provides accurate constant voltage (CV) regulation without an 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