Monolithic Power Systems Inc. MP4033GS-P

Overview

MP4033GS-P 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 adaptive dimmer detection enables deep dimming down to 0.5% and high compatibility with leading- and trailing-edge TRIAC dimmers in residential lighting systems.

For engineers reviewing the MP4033GS-P datasheet, MP4033GS-P pinout, MP4033GS-P application, or MP4033GS-P equivalent, key selection criteria include its SOIC-8 package footprint, VCC charging circuit for sub-100ms start-up, programmable NTC-based thermal fold-back, DIM pin support for warm sunset color-tuning, and ZCD-based zero-current switching for low EMI and high efficiency.

Technical Context

The MP4033GS-P implements proprietary real-current control by reconstructing secondary LED current from primary-side signals-using VREF (0.414V), MULT pin sinusoidal line reference, and S-pin current sensing-eliminating optocoupler feedback. Its multiplier block shapes peak primary current to match line voltage phase, achieving >0.95 power factor without external PFC controllers.

Boundary-conduction mode operation is enforced via ZCD pin monitoring of auxiliary winding resonance; turn-on occurs at valley voltage after tZCD_LEB blanking (1.9–3.36 µs), minimizing MOSFET switching loss and secondary diode reverse-recovery loss. Adaptive dimmer detection uses VMULT thresholds (e.g., VMULT_LD_LOW = 0.08–0.12V, tLEADING = 86–134 µs) to auto-identify leading/trailing edge types and configure DP pull-down strength accordingly.

Key Specifications

Pinout & Package

MP4033GS-P is packaged in SOIC-8 with exposed pad (RoHS-compliant, lead-free). The 8-pin layout supports compact, thermally efficient PCB layouts for enclosed LED drivers.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP4032GS-Z, MP4033GS-P adds NTC-based thermal fold-back and DIM-driven warm sunset control; versus BP57728J, it integrates a 30V/250mΩ MOSFET and DAMP driver, reducing component count and board area for ≤50W designs.

Availability

MP4033GS-P is available at Aetrix Electronics and suitable for residential LED lamps, commercial downlights, industrial panel lights, and hospitality ambient lighting requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP4033GS-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 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, compact, and thermally robust solid-state lighting solutions.

FAQ

What dimmer types does MP4033GS-P support?

MP4033GS-P supports both leading-edge (TRIAC) and trailing-edge (MOSFET/transistor) dimmers via adaptive detection using MULT pin voltage thresholds and timing windows (tLEADING = 86–134 µs, tTRAILING = 388–602 µs). It achieves >95% recognition rate across standard household dimmers and enables deep dimming to 0.5% without flicker.

How does the real-current control method eliminate optocoupler dependency?

The real-current control method calculates LED current from primary-side parameters: VREF (0.414V), transformer turns ratio (N_sec/N_aux), and sense resistor value (R_s). By correlating ZCD timing, MULT voltage, and S-pin current slope, it reconstructs secondary current with ±3% accuracy-removing need for optocoupler, TL431, and associated compensation network.

What protections are included and how do they auto-recover?

MP4033GS-P includes output OVP (4.9–5.7V), output short-circuit, winding short, ZCD short (78–122mV for 33ms), over-temperature (150°C), and supply UVLO (6.55–7.45V). All protections force shutdown and enter auto-restart mode: VCC drops below UVLO threshold, then recharges via internal JFET until VCCH (9.5–10.5V) is reached, resuming operation.

Can MP4033GS-P be used without an NTC thermistor?

Yes-NTC is optional. When NTC is unconnected or open, the IC defaults to full-output operation. If a 10kΩ NTC is connected between NTC pin and GND, thermal fold-back activates when voltage at NTC pin falls below VL_NTC (0.70–0.90V), scaling LED current downward to protect LEDs above 60°C ambient. No external biasing is required.

What is the role of the DAMP pin and when is it required?

The DAMP pin drives an external MOSFET in an RC snubber network across the main transformer primary. It activates during MOSFET turn-off to absorb leakage inductance energy, suppressing voltage spikes and EMI. Required in high-power (>30W) or high-leakage-inductance designs; omitted in low-cost, low-power applications where snubbing is handled passively.

Does MP4033GS-P support analog dimming in addition to TRIAC?

Yes-MP4033GS-P accepts PWM input on the DIM pin (IDIM_SOURCE = 2–4mA, IDIM_SINK = 1.5–4mA) for analog dimming. An external RC filter converts PWM to DC voltage, which modulates LED current proportionally. This enables hybrid dimming: TRIAC for coarse adjustment and PWM for fine-tuning or microcontroller-controlled scenes.

What is the minimum off-time (tOFF_MIN) and why is it critical?

tOFF_MIN is 4–8 µs (10 µs when NTC ≤1.0V). It enforces a lower bound on switching period to prevent excessive frequency rise at low line voltages, ensuring stable BCM operation, predictable EMI profile, and reliable ZCD valley detection. Violating this limit risks false triggering and loss of zero-voltage switching benefit.