Monolithic Power Systems Inc. MP44011HS-LF

Overview

MP44011HS-LF from Monolithic Power Systems is a boundary-conduction-mode (BCM) active power-factor correction (PFC) controller with integrated harmonic injection, designed for pre-regulation in two-stage LED lighting drivers. It operates from 13.4V to 22V supply, delivers precise output over-voltage protection (2.2V–2.4V static threshold), and reduces bus capacitance and transformer size via harmonic-injection functionality. Confirmed in 8-pin SOIC package with 70kHz typical switching frequency.

For engineers reviewing the MP44011HS-LF datasheet, MP44011HS-LF pinout, MP44011HS-LF application, or MP44011HS-LF equivalent, key selection criteria include harmonic-injection capability for THD reduction, ZCS-triggered MOSFET turn-on timing, internal current-sense filtering, ultra-low 40µA start-up current, and compatibility with flyback/boost PFC topologies requiring <1.5A peak primary current.

Technical Context

The MP44011HS-LF implements boundary-conduction-mode control using zero-current sensing (ZCS) on pin 5 to trigger MOSFET turn-on at inductor current zero-crossing, with 2.1V rising-edge and 1.35V falling-edge thresholds. Its multiplier block (pin 3) injects constant-ratio harmonics into the line-voltage reference, generating a choppy sinusoidal current envelope that lowers peak primary current by ~13% versus non-harmonic BCM controllers.

Internal functions include a 2.5V ±15mV precision error amplifier (FB pin), COMP pin clamping (2.2V–6.6V), gate driver with 600mA sink/350mA source capability, and dual OVP: static (2.2V COMP clamp) and dynamic (35–40µA COMP current detection). The on-chip CS filter suppresses high-frequency noise without external RC components.

Key Specifications

Pinout & Package

MP44011HS-LF is housed in an industry-standard 8-pin SOIC package (JEDEC MS-012, variation AA), with 1.27mm pitch, 3.9mm width, and 4.9mm length. Thermal resistance θ_JA = 90°C/W on 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boundary-mode PFC controller applications.

Compared with MP44010HS-LF, MP44011HS-LF delivers measurable reductions in transformer size and bus capacitance without changing layout or control loop design; versus UCC28051DR, it offers simpler implementation and lower BOM cost but trades off fixed-frequency EMI predictability for variable-frequency efficiency optimization.

Availability

MP44011HS-LF is available at Aetrix Electronics and suitable for LED lighting drivers, two-stage AC/DC adapters, industrial boost PFC pre-regulators, and low-THD consumer power supplies requiring stable component supply across extended temperature ranges.

Supply support for MP44011HS-LF 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 20 years of expertise in DC/DC converters, LED drivers, and power-factor correction solutions.

The MP44011 belongs to MPS's boundary-mode PFC controller product line, engineered specifically for cost-sensitive, space-constrained LED lighting and universal-input AC/DC systems where harmonic injection improves system-level efficiency and component sizing.

FAQ

What is the purpose of the harmonic injection function in MP44011HS-LF?

The harmonic injection function modifies the multiplier output to generate a "choppy sinusoidal" current reference, reducing peak primary current in flyback PFC topologies. This allows smaller transformer cores and lower bus capacitance-confirmed in MPS design example where 47µF capacitor replaces 68µF, and EE25 core replaces EE30-without compromising power factor or THD compliance.

How does the ZCS pin enable boundary-conduction-mode operation?

Pin 5 (ZCS) senses the falling edge of auxiliary winding voltage to detect inductor current zero-crossing. When voltage drops below 1.35V, the internal comparator triggers MOSFET turn-on; hysteresis (2.1V rising / 1.35V falling) prevents chatter. Internal 175µs re-start timer ensures reliable startup even without ZCS signal during initial power-up.

Can MP44011HS-LF be used in boost PFC configurations?

Yes-MP44011HS-LF supports both boost and flyback PFC topologies. In boost mode, the MULT pin still injects harmonics to shape input current, and ZCS pin remains unused (tied to GND per MPS layout guide). Design Example section confirms functional validation in boost configuration with 85–265VAC input and 400VDC output.

What is the maximum gate drive current capability of MP44011HS-LF?

The GATE pin provides 600mA sink and 350mA source current, verified under load conditions in Electrical Characteristics table. This drives standard 800V MOSFETs like FQPF8N80C directly without external buffer, with VOL = 1.5V and VOH = 5.4V at 200mA sink/source, ensuring robust turn-on/turn-off in high-noise environments.

How does the dual OVP scheme improve system reliability?

MP44011HS-LF implements static OVP (2.2V COMP clamp) for sustained overvoltage during light-load conditions and dynamic OVP (35–40µA COMP current detection) for fast transients. Static OVP enters idle state until regulation resumes; dynamic OVP triggers immediate shutdown and 80–280µs restart delay, preventing capacitor overvoltage and MOSFET avalanche failure in both steady-state and fault scenarios.

Is the FB pin compatible with standard optocoupler-based feedback networks?

Yes-the FB pin accepts standard 2.5V-referenced optocoupler feedback circuits. MPS Application Note AN-103 confirms use with PC817 and TL431, where COMP pin connects to optocoupler cathode and FB pin ties to TL431 reference. Layout guidance emphasizes short traces to FB and local ceramic decoupling to maintain regulation accuracy within ±1%.

What thermal derating applies to MP44011HS-LF in SOIC-8 package?

With θ_JA = 90°C/W on 4-layer PCB, maximum continuous power dissipation drops from 1.4W at 25°C ambient to 0.89W at 85°C ambient (calculated as (150°C − T_A) / 90). Internal thermal shutdown activates above 150°C junction temperature, protecting the device during overload or poor heatsinking conditions.