Monolithic Power Systems Inc. MP150GS-P

Overview

MP150GS-P from Monolithic Power Systems is a primary-side constant voltage (CV) regulator IC with integrated 500V/30Ω MOSFET, supporting Buck, Buck-boost, Boost, and Flyback topologies for offline AC/DC conversion. It delivers up to 2W output power, achieves <150mW no-load consumption, and features green-mode operation with frequency foldback and peak current compression. It targets low-power offline applications including home appliance standby supplies and white goods power rails.

For engineers reviewing the MP150GS-P datasheet, MP150GS-P pinout, MP150GS-P application, or MP150GS-P equivalent, this page provides verified technical context, SOIC8 package details, CV regulation behavior under light load, thermal shutdown (150°C), and protection mechanisms including OLP (170ms delay), SCP (450mA threshold), and open-loop detection (60mV FB threshold).

Technical Context

The MP150GS-P implements primary-side regulation using sampled output voltage via an internal error amplifier and ramp-compensated feedback comparator-eliminating optocoupler dependency. Its control loop adjusts switching frequency and peak current limit dynamically: both decrease under light load to maintain high efficiency, with minimum off-time fixed at 18μs in steady state.

It integrates a 500V vertical DMOS power switch with 30Ω R_DS(on), driven by a self-powered start-up circuit sourcing from the DRAIN pin. Protection logic includes latch-off behavior during sustained faults, with VCC hysteresis (5.1V–5.6V) and automatic restart after VCC discharges to 2.4V under thermal shutdown or SCP.

Key Specifications

Pinout & Package

MP150GS-P is housed in an SOIC8 package with exposed drain pad for thermal enhancement. Pin 1 is VCC, Pin 2 is FB, Pins 3 and 4 are SOURCE (internally tied), Pin 7 is DRAIN, and Pins 5, 6, and 8 are NC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side offline regulator applications.

Compared with MP157GS-Z, MP150GS-P provides lower system cost and simpler layout for ≤2W applications, while LNK304DG delivers tighter regulation at the expense of higher design complexity and reduced light-load efficiency optimization.

Availability

MP150GS-P is available at Aetrix Electronics and suitable for home appliance standby supplies, white goods auxiliary rails, and IoT edge device AC/DC converters requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP150GS-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with over two decades of leadership in DC/DC, AC/DC, and motor drive solutions.

The MP150 product line delivers highly integrated primary-side regulators targeting cost-sensitive, low-power offline applications-designed to replace traditional optocoupler-based feedback architectures with simplified, reliable, and energy-efficient alternatives.

FAQ

What topologies does MP150GS-P support, and which require isolation?

MP150GS-P supports Buck, Buck-boost, Boost, and Flyback topologies. Only Flyback provides galvanic isolation via transformer coupling; the other three operate in non-isolated configurations with direct feedback paths. Flyback is selected when safety isolation (e.g., for user-accessible outputs) or multiple output rails are required.

How does MP150GS-P achieve no-optocoupler constant voltage regulation?

MP150GS-P samples the output voltage indirectly through a capacitor coupled to the secondary winding (in Flyback) or directly across the output (in Buck/Buck-boost/Boost). The FB pin monitors this sampled voltage and compares it to a 2.55V internal reference, adjusting switching timing to maintain regulation without secondary-side components.

What is the role of the minimum off-time limit, and how does it affect power capability?

The 18μs minimum off-time limit constrains the maximum duty cycle and thus the maximum energy transfer per cycle. It directly determines achievable output power: smaller inductors reduce stored energy, risking failure at full load unless inductance is sized per the P_min vs. L curves in the datasheet (e.g., ≥0.6mH for 5V/100mA).

Can MP150GS-P operate with universal AC input (85–265VAC)?

Yes-MP150GS-P's 500V integrated MOSFET and internal HV start-up circuit enable direct operation from universal AC input after bridge rectification. Design examples confirm stable 5V/200mA output across 85–265VAC with appropriate input capacitor selection (e.g., 22μF for 2kV surge immunity).

What protection features are implemented, and how do they behave during fault conditions?

MP150GS-P includes thermal shutdown (150°C), short-circuit protection (450mA), over-load protection (1.7V FB threshold with 170ms timer), and open-loop detection (60mV FB). All protections force latch-off, discharge VCC to 2.4V via 16μA current source, then restart automatically once VCC recharges above 5.3V.

Is MP150GS-P pin-compatible with other MPS primary-side regulators like MP157?

No-MP150GS-P uses SOIC8 with pins 3/4 as SOURCE and pin 7 as DRAIN, while MP157GS-Z has different pin assignments (e.g., DRAIN on pin 8) and added functionality (soft-start, enhanced EMI control). Layout and schematic changes are required for substitution.

What is the recommended feedback resistor range for stable regulation?

R2 should be between 5kΩ and 10kΩ (typical), with R1 calculated to set V_FB = 2.55V at target output voltage (e.g., R1 = R2 × (V_OUT/2.55 − 1)). Values outside this range risk noise sensitivity (too large) or excessive VCC loading (too small), degrading regulation accuracy.