company blog about Recycle ON AC-DC Power Conversion:Offline Controller,Offline Regulator,Power Factor Controller,Secondary Side Controller

Recycle ON AC-DC Power Conversion:Offline Controller,Offline Regulator,Power Factor Controller,Secondary Side Controller

Shenzhen Mingjiada Electronics Co., Ltd., as a leading enterprise in the electronic component recycling industry, provides comprehensive recycling solutions through professional services, highly competitive prices and standardised operations.

Recycling Advantages:

Pricing and Funding: We offer high-value cash recycling services with competitive quotes and swift settlement, helping customers quickly realise the value of their stock and recover funds.

Valuation System: Our specialist valuation team utilises scientific testing procedures, advanced equipment and experienced engineers to provide rapid and accurate valuations and quotations for chips.

Recycling Scope: We handle an extremely wide range of products, covering virtually all brands and categories. Whether it is popular chips or niche, rare models, we are able to process them.

Network and Services: We have established a global recycling network spanning multiple countries, supporting worldwide distribution and offering flexible transaction methods and convenient services.

Compliance and Guarantees: We strictly adhere to official recycling channels and only accept materials from legitimate sources. Formal contracts ensure that transactions are secure, transparent and compliant.

I. Offline Controllers

Offline controllers are discrete primary-side PWM/PFM controllers that are paired with external, independent high-voltage MOSFETs. They support mainstream isolated topologies such as flyback, forward and LLC resonant, and are categorised into three main types: fixed-frequency current-mode, quasi-resonant (QR) and resonant controllers. They are the mainstream choice for medium- to high-power AC-DC power supplies.

Key Product Features

1. Quasi-Resonant (QR) Flyback Series (NCP1341, NCP1342)

Equipped with valley-locking switching technology to reduce switching losses; features a built-in high-voltage start circuit and integrated X2 capacitor discharge function, easily achieving <30 mW no-load power consumption; Equipped with silent skip-cycle mode and frequency jitter to optimise EMI; integrates overpower compensation, NTC over-temperature protection, output OVP and short-circuit protection, designed for high-density laptop adaptors, TV power supplies and high-power USB-PD fast charging.

2. Fixed-Frequency Current-Mode Flyback Controllers (NCP1250, NCP1239)

Peak current-mode control, supporting frequency folding and skip-cycle energy saving at light loads; configurable adjustable overpower protection (OPP) with built-in leading-edge blanking; compact TSOP-6 package, suitable for 20–65W consumer adapters and IoT device power supplies.

3. LLC Resonant Controller (FAN7688)

Charge-controlled architecture PFM resonant controller, suitable for LLC topologies; supports adaptive dead-time and synchronous rectification co-control, with a wide frequency modulation range; closed-loop soft-start suppresses inrush current, widely used in server power supplies, high-power industrial power supplies, and downstream DC-DC converters in vehicle chargers.

Typical Applications

Laptop adaptors, monitor power supplies, ATX computer power supplies, industrial isolated power supplies, and high-power energy storage auxiliary power supplies.

II. Offline Voltage Regulators

Offline voltage regulators are monolithic integrated switching power supplies (integrated PWM controller + 700V high-voltage SenseFET), offering a high degree of integration to minimise the number of external components. They are designed for low-cost, low-power offline flyback solutions up to 50W.

Key Product Features

Representative Models: NCP1071, FSL136HR

Built-in 700V avalanche-rated high-voltage switching transistor, eliminating the need for an external MOSFET;

Dynamic Self-Supply (DSS) technology; in some designs, this eliminates the need for an auxiliary winding, simplifying transformer design;

Integrated soft start, frequency jittering, cycle-by-cycle current limiting, short-circuit time-out protection and thermal shutdown;

Automatically enters frequency folding and skip-cycle modes when the load decreases, optimising standby power consumption;

Package options include SOT-223 and PDIP-7, with a small PCB footprint and significant BOM cost advantages.

Typical Applications

Smart meters, auxiliary power supplies for household appliances, power supplies for small IoT modules, small chargers (5–30 W), and auxiliary power supplies for lighting drivers.

III. Power Factor Controllers

Active power factor correction (PFC) controllers are positioned downstream of the AC input rectifier stage. They reshape the input current waveform, suppress grid harmonics, improve the power factor, and comply with the IEC 61000-3-2 harmonic standard. They are categorised into two main approaches: traditional Boost PFC and the next-generation bridge-less totem-pole PFC.

Core Product Series

1. Traditional Boost PFC Controllers

These include Critical Conduction Mode (CrM) (NCP1607) and Continuous Conduction Mode (CCM) (FAN9672 interleaved parallel PFC); they support constant conduction time control, feature built-in THD optimisation circuits, and are suitable for television power supplies and general-purpose industrial power supplies.

2. Totem-Pole Bridge-less PFC Controllers (NCP1680, NCP1681)

Onsemi’s benchmark products, which eliminate the traditional diode rectifier bridge to significantly reduce conduction losses; support multi-mode operation (CCM/CrM), and integrate AC phase detection and digital loop compensation; suitable for 300W–3kW server power supplies, 5G communication power supplies, and OBC (on-board chargers) for electric vehicles, with maximum efficiency approaching 99 per cent, and compatible with SiC/GaN wide-bandgap devices.

3. PFC+PWM All-in-One Controller (FAN6921ML, FL7921R)

A monolithic integrated CrM-PFC + QR flyback controller that realises two-stage power control on a single chip, significantly streamlining the BOM; it is the preferred solution for LED drivers and small-to-medium power display power supplies.

Typical Applications

Server power supplies, telecommunications power supplies, high-power LED drivers, automotive OBCs, commercial charging points, and industrial high-power AC-DC front-ends.

IV. Secondary-Side Controllers

Installed on the isolated secondary side of the transformer, these are primarily categorised as synchronous rectification controllers and secondary-side voltage regulators. They are responsible for enhancing rectification efficiency and achieving high-precision output voltage regulation, thereby overcoming the limitations of traditional primary-side optocoupler feedback.

1. Synchronous Rectification Controller (Representative Model: NCP4305)

A dedicated driver IC for SR MOSFETs, compatible with DCM/CCM flyback, QR flyback and LLC resonant topologies;

Precise turn-on/turn-off thresholds and extremely low propagation delay maximise the SR conduction window;

Configurable minimum turn-on/turn-off blanking times to suppress PCB parasitic oscillations;

Supports Kelvin sensing and is compatible with both silicon MOSFETs and GaN devices;

Maintains high efficiency under both high and low loads, replacing the secondary-side rectifier diode to significantly reduce conduction losses.

2. Secondary-Side Closed-Loop Voltage Regulator Controller (NCP4390)

Achieves closed-loop regulation of isolated power supplies by sampling directly at the output, eliminating the need for optocouplers and thereby addressing issues such as optocoupler ageing and transmission delays; significantly improved transient response speed, with an integrated complete protection chain, suitable for high-end 48V server power supplies and high-density energy storage power supplies.

Typical Applications

High-power PD fast charging, server power supplies, LLC resonant power supplies, high-density industrial power supplies.