Monolithic Power Systems Inc. MP4653GY-Z

Overview

MP4653GY-Z from Monolithic Power Systems is a secondary-side CC/CV mode LLC controller for large-size TV LED backlighting, supporting 9–30V input and delivering two 180° phase-shifted gate drive signals (GL/GR) to external MOSFETs via gate-drive transformer. It integrates dual control loops-constant current (IFB feedback, 0.2V reference) and constant voltage (VFB sampling, 2.4V OVP threshold)-to regulate both LED string current and DC bus voltage (e.g., 400V bus), enabling system power generation (12V/5V) with auxiliary DC/DC converters. Used in 4-string LED TV backlights with analog/PWM dimming.

For engineers reviewing the MP4653GY-Z datasheet, MP4653GY-Z pinout, MP4653GY-Z application, or MP4653GY-Z equivalent, key selection considerations include its real LIPS architecture, audible-noise-free PWM dimming (continuous GL/GR drive during PWM on/off), integrated hiccup-mode fault recovery, and SOIC20 package compatibility with high-voltage LED string protection (open/short-to-GND, overvoltage, overcurrent).

Technical Context

The MP4653 employs frequency-modulated LLC control where operating frequency (35.6–2.8 kHz range) is dynamically set by the larger of two compensation outputs-ICOMP (current loop) and VCOMP (voltage loop)-enabling seamless CC/CV mode transition synchronized to PWMIN duty cycle. At PWM high, ICOMP regulates LED current via IFB feedback; at PWM low, VCOMP regulates bus voltage using sampled VFB as reference.

Its protection architecture uses dedicated sensing pins-VOCP (bus overcurrent, -100 mV threshold), SSD (LED short detection, -200 mV), and four VLEDx inputs (differential OVP, 2.4 V threshold)-with independent hiccup timers (ICOMP/VCOMP charge/discharge currents: 2 µA typ) and blanking delays (100–350 µs) to distinguish transient faults from steady-state conditions.

Key Specifications

Pinout & Package

MP4653GY-Z is housed in a 20-pin SOIC package with exposed thermal pad (pin 19 = GND). Pin functions are validated per MPS MP4653 Rev 1.01 datasheet and confirmed on official Monolithic Power Systems product page.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CC/CV LLC LED driver applications.

Compared with MP4655GY-Z, MP4653GY-Z offers superior low-frequency stability for large-panel bus regulation and simpler layout due to secondary-side sensing; versus UCC25710DWR, it eliminates optocoupler drift and enables faster transient response for dynamic dimming in premium TVs.

Availability

MP4653GY-Z is available at Aetrix Electronics and suitable for large-panel LCD TV backlighting, commercial video wall power systems, and outdoor digital signage requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP4653GY-Z 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 MP4653 belongs to MPS's Real LIPS™ LED driver product line, engineered specifically for secondary-side-controlled, high-efficiency LLC resonant converters in large-format TV backlight systems demanding ultra-low audible noise and robust fault tolerance.

FAQ

What is the purpose of the SS and FSET pins working together?

The SS (Soft Start) and FSET (Frequency Set) pins jointly determine the MP4653GY-Z's operating frequency and startup behavior. A resistor network (RSS_FSET in parallel with Rss–Css series) connects to SS, setting both soft-start timing and minimum frequency; FSET, tied to ground via RFSET, adjusts frequency range. Their combined sourcing current defines the LLC tank's resonant frequency-ensuring controlled inrush and stable regulation from first power-on.

How does the MP4653GY-Z eliminate audible noise during PWM dimming?

Unlike conventional LED drivers that halt switching during PWM off periods, the MP4653GY-Z maintains continuous GL and GR gate drive signals across both PWM on and off intervals. This keeps the LLC resonant tank energized and prevents mechanical vibration in transformers and inductors-directly eliminating coil whine while preserving bus voltage regulation in CV mode.

Can the MP4653GY-Z support fewer than four LED strings?

Yes. When using fewer than four LED strings, the unused VLEDx pins (e.g., VLED3 and VLED4 for a 2-string design) must be tied together with the active VLED pins (VLED1/VLED2). This ensures proper differential voltage monitoring and avoids false OVP or short-detection triggers-confirmed in the MP4653 Rev 1.01 datasheet Section "PIN FUNCTIONS".

What protection features activate during an LED string open fault?

During an LED string open fault, the IFB pin voltage drops below 0.1 V, triggering immediate ICOMP-based hiccup mode: the internal current source charges ICOMP to 3 V, then discharges it to 0.45 V, repeating until fault clears. Simultaneously, VLEDx pin voltages diverge, activating differential OVP detection-both mechanisms are fully integrated and require no external components.

Is the 9 V gate drive sufficient for driving 600 V GaN FETs?

Yes-the MP4653GY-Z's 9 V GL/GR outputs are designed to drive gate-drive transformers feeding high-side/lower-side GaN or SiC FETs in LLC half-bridges. Its 2 Ω pull-down and 7.5 Ω pull-up ensure fast edge rates (600–900 ns dead time), and the 1 A peak source/sink capability supports typical gate-charge requirements for 600 V devices up to 150 mΩ Rds(on).

How does the VFB sampling mechanism prevent regulation errors during PWM transitions?

The MP4653GY-Z samples VFB only during the PWM high interval-when LED current is actively regulated-and holds that sampled value as the CV reference during PWM low. This decouples bus voltage regulation from LED current ripple and dimming transients, ensuring stable 400 V bus control even at 2 kHz PWM frequencies with <±0.5% error.

Does the MP4653GY-Z require external compensation components?

Yes-external compensation networks are mandatory: a capacitor (or RC network) from ICOMP to GND for the current loop, and another from VCOMP to GND for the voltage loop. These set loop bandwidth and phase margin; typical values are 1 nF + 10 kΩ for ICOMP and 2.2 nF + 4.7 kΩ for VCOMP, per the MP4653 evaluation board design example.