Monolithic Power Systems Inc. MP4033GK

Overview

MP4033GK from Monolithic Power Systems is a TRIAC-dimmable, primary-side-control offline LED controller with integrated active PFC, designed for isolated flyback LED drivers up to 50W. It delivers accurate LED current regulation using real-current control from primary-side sensing, operates in boundary-conduction mode (BCM), and supports warm sunset dimming via the DIM pin. Its adaptive phase-cut dimmer detection ensures compatibility with leading- and trailing-edge TRIAC dimmers.

For engineers reviewing the MP4033GK datasheet, MP4033GK pinout, MP4033GK application, or MP4033GK equivalent, key selection considerations include its MSOP-10 package, programmable NTC-based thermal fold-back, ZCD-based zero-current switching, internal 30V/250mΩ MOSFET, and dual-mode dimming (TRIAC + PWM/analog) for residential and commercial solid-state lighting.

Technical Context

The MP4033GK implements a proprietary real-current–control method that derives LED current accuracy from primary-side signals-specifically VREF (0.414 V), MULT pin sinusoidal reference, and S-pin current sense-eliminating optocoupler dependency. Its multiplier circuit shapes the peak primary current to match line voltage phase, achieving >0.9 PF without secondary feedback.

It uses adaptive dimmer detection logic based on VMULT thresholds (e.g., VMULT_LD_LOW = 0.10 V, VMULT_TL_HIGH = 0.45 V) and timing windows (tLEADING = 100 µs, tTRAILING = 450 µs) to auto-identify dimmer type and adjust COMP clamp levels (VCOMPL_LD = 1.88 V, VCOMPL_TL = 1.58 V) and dimming pull-down currents (IDP_STRONG_LD = 35 mA, IDP_TL = 150 mA).

Key Specifications

Pinout & Package

MP4033GK is packaged in a thermally enhanced MSOP-10 (3 mm × 3 mm, 0.5 mm pitch) with exposed pad for improved heat dissipation. The package supports surface-mount assembly and meets JEDEC MO-187 standards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar TRIAC-dimmable offline LED controller applications.

Compared with NCL30000 and AL1676, MP4033GK uniquely integrates adaptive dimmer detection, warm sunset dimming via DIM pin, NTC-based thermal fold-back, and an internal 30 V MOSFET-enabling compact, high-PF, fully featured single-stage LED drivers without secondary feedback.

Availability

MP4033GK is available at Aetrix Electronics and suitable for residential LED lamps, commercial downlights, and industrial high-bay lighting requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP4033GK 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 design centers in the US, China, and Taiwan, and global distribution through authorized partners.

The MP4033 belongs to MPS's LED lighting controller product line, engineered specifically for TRIAC-dimmable, single-stage, isolated offline LED drivers targeting energy-efficient, thermally robust, and dimmer-compatible solid-state lighting systems.

FAQ

What is the function of the DAMP pin on MP4033GK?

The DAMP pin drives an external damping MOSFET to suppress voltage ringing during the main MOSFET's turn-off transition. It activates when VMULT falls below 0.25 V and deactivates above 0.35 V, reducing EMI and preventing false ZCD triggering. Its pull-down current is 370 µA typical, with 15 V clamp protection.

How does MP4033GK achieve primary-side LED current accuracy without secondary feedback?

MP4033GK uses its proprietary real-current–control algorithm, which calculates LED current from primary-side parameters: VREF (0.414 V), transformer turns ratio (N), and sense resistor value (R_s). The formula I_LED ≈ V_REF × N / (2 × R_s) is implemented via internal multiplier and COMP amplifier dynamics, validated to ±3% accuracy across line/load/temperature.

Can MP4033GK support both leading-edge and trailing-edge TRIAC dimmers in the same design?

Yes-MP4033GK performs automatic dimmer-type detection each AC half-cycle using MULT pin voltage thresholds (e.g., VMULT_LD_LOW = 0.10 V, VMULT_TL_HIGH = 0.45 V) and timing windows (tLEADING = 100 µs, tTRAILING = 450 µs). It then configures COMP clamp level, dimming pull-down strength, and ZCD behavior accordingly-no external configuration required.

What protections are included in MP4033GK and how do they recover?

MP4033GK includes output over-voltage (OVP), output short-circuit (SCP), winding short, ZCD short, supply UVLO, and over-temperature protection. All faults trigger auto-restart: the IC enters quiescent mode (IQ_FAULT = 340 µA), waits for VCC to drop below VCCEN (7.0 V), then recharges VCC and resumes switching-no manual reset needed.

Is the internal MOSFET in MP4033GK sufficient for 50 W LED applications?

Yes-the integrated 30 V, 250 mΩ MOSFET supports up to 50 W in flyback configurations with 230 VAC input, as verified on the EV4033-K-00A evaluation board (24 V/420 mA output). Thermal performance is ensured by MSOP-10's θJA = 150 °C/W and internal thermal fold-back triggered at 150 °C junction temperature.

How is analog dimming implemented using the NTC pin?

Analog dimming is implemented by applying a PWM signal (via series 1 kΩ resistor) to the NTC pin, which overrides the NTC thermistor function. The IC interprets the average voltage at NTC as a dimming command: 0.38 V = 0% output, 1.20 V = 100% output. This enables smooth 0–100% brightness control without modifying the main current loop.