MP157 Smallest Energy Efficient Off-line Regulator TSOT23

MP157 Smallest Energy Efficient Off-line Regulator TSOT23

MP157 is a primary side regulator providing accurate constant voltage (CV) regulation without the Opto-coupler.

Key Specifications

Features

• Primary side constant voltage (CV) control, supporting Buck, Buck-Boost, Boost and Flyback topologies
• Integrated 500V/10Ω MOSFET
• < 100mW No-load power consumption
• Up to 6W output power
• Maximum discontinuous conduction mode (DCM) output current less than 225mA, maximum continuous conduction mode (CCM) output current less than 360mA
• Low Vcc Operating Current
• Frequency Foldback
• Limited maximum frequency
• Peak Current Compression
• Internal High Voltage Current Source

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