Monolithic Power Systems Inc. HF920BGS-P

Overview

HF920BGS-P from Monolithic Power Systems is a monolithic 900V flyback switching regulator IC integrating a 15Ω MOSFET, programmable fixed-frequency control (up to 150kHz), EMI-optimized frequency jittering (±3.5%), and ultra-low standby power (<30mW no-load). It delivers up to 10W output at 230VAC in SOIC14-11 package and targets high-reliability AC/DC conversion in smart meters, industrial controls, and large appliances.

For engineers reviewing the HF920BGS-P datasheet, HF920BGS-P pinout, HF920BGS-P application, or HF920BGS-P equivalent, key selection criteria include its 900V integrated MOSFET breakdown rating, burst-mode light-load regulation, frequency-doubling under overload, VCC UVLO hysteresis (4V), and dual-package availability (SOIC8-7A/SOIC14-11) with validated thermal resistance (θJA = 70°C/W).

Technical Context

The HF920BGS-P implements peak current mode control with internal slope compensation and leading-edge blanking (tLEB1 = 385ns, tLEB2 = 350ns) to ensure stable loop dynamics and prevent false triggering during MOSFET turn-on transients. Its feedback path uses a 3.7× FB-to-current-set-point division ratio (KDIV) and regulates output via optocoupler-coupled voltage sensing on the FB pin.

EMI mitigation is achieved through three concurrent mechanisms: externally programmable switching frequency (via FSET resistor), ±3.5% frequency jittering over 256-cycle carrier, and optional frequency doubling (enabled by 1nF capacitor on FSET) that doubles fSW to 111kHz during overload to maintain regulation despite 50% transformer inductance loss.

Key Specifications

Pinout & Package

HF920BGS-P is available in SOIC14-11 package (14-pin, 0.150" wide body, exposed thermal pad not present). Pin functions are validated per MPS datasheet Rev. 1.0 (2020): pins 1/2/7/8 = GND; pin 9 = S (MOSFET source, current sense input); pin 14 = D (MOSFET drain, HV start-up input); pin 3 = VCC; pin 4 = FSET; pin 5 = PRO; pin 6 = FB; pin 13 = NC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar offline flyback regulator applications.

Compared with MP6004GQ-Z and UCC28881DR, HF920BGS-P uniquely combines 900V ruggedness, programmable EMI suppression, and frequency doubling-enabling single-chip compliance with IEC 61000-4-5 surge immunity and CISPR-11/32 Class B without auxiliary filtering.

Availability

HF920BGS-P is available at Aetrix Electronics and suitable for smart metering, industrial PLC power supplies, large appliance control boards, and building automation gateways requiring stable component supply across global AC grid voltages (85–420VAC).

Supply support for HF920BGS-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 power management ICs, with over 20 years of expertise in monolithic HV integration and EMI-optimized switching architectures.

The HF920B product line was designed specifically for high-voltage offline AC/DC conversion in mission-critical infrastructure applications where reliability, low standby power, and EMI compliance are non-negotiable.

FAQ

What is the maximum continuous output power achievable with HF920BGS-P at 230VAC input?

The HF920BGS-P delivers up to 10W continuous output power at 230VAC ±15% input when packaged in SOIC14-11, validated per Table 1 of the datasheet under TA = 50°C with specified PCB layout (2.5cm² GND copper). This assumes single-output 12.5V/800mA configuration and BCM operation at minimum input.

How does the frequency doubling mode improve system robustness?

Frequency doubling activates when FB voltage reaches 3.65V (OLP threshold), doubling fSW to 111kHz. This allows the converter to maintain regulation even if transformer inductance drops by up to 50% due to external magnetic fields-critical for industrial environments near motors or solenoids where core saturation would otherwise cause output collapse.

Can HF920BGS-P operate without an auxiliary winding?

Yes. The IC incorporates a high-voltage start-up current source (2mA typical) sourced directly from the D pin, enabling initial operation without auxiliary winding. Once VCC reaches 13V, the internal current source disables and the auxiliary winding takes over-ensuring reliable start-up even with poorly coupled transformers.

What is the purpose of the PRO pin, and how is it typically implemented?

The PRO pin provides configurable external shutdown: pulling it above 3.1V (with 0.2V hysteresis) forces immediate IC shutdown and auto-restart upon fault clearance. Typical implementations include input overvoltage detection via resistor divider or thermal cutoff from NTC thermistors placed on critical components like rectifier bridges.

How does the internal leading-edge blanking (LEB) function protect the current-sense path?

HF920BGS-P employs two independent LEB timers: 385ns for normal current limiting and 350ns for short-circuit protection. During these intervals, the S pin signal is ignored to prevent false triggering from MOSFET turn-on current spikes-ensuring accurate peak current detection and preventing premature shutdown during normal switching transitions.

Is HF920BGS-P RoHS-compliant and halogen-free?

Yes. HF920BGS-P is lead-free, halogen-free, and fully compliant with the EU RoHS Directive 2011/65/EU. MPS confirms green status on its official website under Quality Assurance documentation, with material declarations available upon request for full supply chain traceability.