Monolithic Power Systems Inc. MP4033GSE

Overview

MP4033GSE 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, operates in boundary-conduction mode, and supports analog dimming via PWM input or phase-cut dimmers. Its SOIC-14 package includes NTC-based thermal fold-back and warm sunset color/brightness control.

For engineers reviewing the MP4033GSE datasheet, MP4033GSE pinout, MP4033GSE application, or MP4033GSE equivalent, key selection criteria include TRIAC dimmer compatibility, primary-side current sensing accuracy, VCC auto-recharge behavior, ZCD-based zero-current switching timing, and programmable NTC fold-back threshold for thermal derating in enclosed luminaires.

Technical Context

The MP4033GSE implements adaptive dimmer-type detection (leading/trailing edge) using MULT pin voltage thresholds and timing windows (tLEADING = 86–134 µs, tTRAILING = 388–602 µs), enabling deep dimming down to <1% with stable flicker-free operation. Its proprietary real-current control calculates LED output current from primary-side parameters: I_LED ≈ (V_REF × N_sec) / (2 × R_s), where V_REF = 0.414 V ±1.4%.

Boundary-conduction mode operation is enforced by ZCD-triggered MOSFET turn-on after tZCD_LEB blanking (0.95–3.36 µs), minimizing switching losses and eliminating secondary diode reverse-recovery noise. Active PFC is achieved via multiplier-driven sinusoidal current shaping, with VMULT linear range of 0–3 V and gain K = 0.90–1.60 V⁻¹, clamped at VS_CLAMP_H = 1.97–2.17 V to limit peak current.

Key Specifications

Pinout & Package

MP4033GSE is housed in a 14-pin SOIC package (body width 3.9 mm, pitch 1.27 mm) with exposed pad not present; thermal resistance θJA = 86°C/W on 4-layer PCB per JESD51-7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4032GSE, MP4033GSE adds NTC-based thermal fold-back and DIM-controlled warm sunset dimming - critical for residential smart lighting. Versus BP5778E, MP4033GSE eliminates optocoupler dependency and achieves higher power density via integrated MOSFET and primary-side sensing, though with slightly relaxed current regulation tolerance (±3% vs ±2%).

Availability

MP4033GSE is available at Aetrix Electronics and suitable for residential dimmable downlights, commercial office troffers, and industrial high-bay LED fixtures requiring stable component supply, long-lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for MP4033GSE 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 leadership in DC/DC converters, LED drivers, and motor controllers.

The MP4033 product line targets cost-sensitive, high-efficiency TRIAC-dimmable LED lighting systems requiring primary-side regulation, active PFC, and robust fault protection - especially for retrofit and new-build architectural lighting.

FAQ

What is the function of the DAMP pin on MP4033GSE?

The DAMP pin drives an external MOSFET to suppress voltage ringing at the drain node during turn-off transitions. This reduces electromagnetic interference and prevents false triggering of the ZCD comparator. It operates with 290–450 µA pull-down current and 70–110 µA pull-up current, with clamp voltage up to 16.5 V.

How does MP4033GSE achieve TRIAC dimmer compatibility without secondary feedback?

It uses adaptive detection of dimmer type (leading/trailing edge) via MULT pin voltage thresholds and timing windows (tLEADING = 86–134 µs, tTRAILING = 388–602 µs), combined with phase-cut-based dimming control that adjusts current reference in real time. No optocoupler or secondary sensing is needed.

Can MP4033GSE be used in non-isolated buck-derived topologies?

No - MP4033GSE is specifically designed for isolated flyback topologies with ZCD-based zero-current switching. Its real-current control algorithm, OVP sampling from auxiliary winding, and boundary-mode timing rely on transformer-coupled energy transfer and cannot be applied to non-isolated configurations.

What is the minimum off-time (tOFF_MIN) specification and its impact on EMI?

tOFF_MIN is 4–8 µs (10 µs when NTC ≤1.0 V). This internal minimum blanking period limits maximum switching frequency, reducing high-frequency spectral content and easing EMI filter design. It ensures stable operation even at low line voltages where natural frequency would otherwise exceed 500 kHz.

How does the NTC input affect LED current regulation?

The NTC pin accepts a thermistor to scale LED current downward as ambient temperature rises. When NTC voltage falls below VL_NTC (0.70–0.90 V), thermal fold-back begins; at VH_NTC (1.14–1.36 V), full current resumes. This extends LED lifetime by limiting junction temperature in enclosed fixtures.

Is MP4033GSE pin-compatible with MP4033GS or MP4033GK?

No - MP4033GSE (SOIC-14) has different pin count and assignment than MP4033GS (SOIC-8) and MP4033GK (MSOP-10). Key differences include dedicated NTC and DIM pins in SOIC-14, whereas SOIC-8 omits both and MSOP-10 includes NTC but not DIM. Layout and schematic redesign is required for substitution.

What protection features auto-restart after fault clearance?

All protections - output over-voltage, output short-circuit, winding short, ZCD short, supply UVLO, and over-temperature - feature auto-restart. After fault, VCC drops below VCCEN (6.55–7.45 V), triggering internal recharge and resumption of normal operation within 500 ms, provided the fault condition is removed.