Introduction

LLC topology, known for its high efficiency, has replaced traditional flyback circuits in many applications, achieving higher efficiency and lower energy consumption in household appliances. LLC topology is not only suitable for traditional household appliances with voltage requirements but is also gradually being used in e-bike chargers.

Due to the fixed input and output voltages required by LLC topology, and considering that applications using this topology are high-power sources, an additional PFC (Power Factor Correction) is needed for LLC. PFC not only corrects the power factor but also stabilizes the DC voltage supplied to the LLC. However, as demonstrated in some teardown videos, early chargers used separate PFC controllers and LLC controllers, leading to a higher component count.

As semiconductor technology has advanced, numerous manufacturers have introduced combined PFC and LLC controllers, integrating the functionalities of two chips into one, and simplifying power supply designs. This integration reduces component count, allows PFC to dynamically adjust its working state based on the LLC load, achieving higher efficiency. Consequently, this integration has become the mainstream solution for high-performance power supplies in recent years.

Why LLC Needs to be Used with PFC

To understand why an LLC controller needs to be paired with PFC, it's essential to comprehend the LLC architecture. Simply put, the LLC architecture refers to a power circuit topology containing inductors (L), capacitors (C), and inductors (L) that achieve efficient DC-DC conversion through a resonant circuit formed by these components. The LLC architecture employs Zero-Voltage Switching (ZVS) soft switching technology, known for its high operating frequency, low losses, high efficiency, and compact size, thereby enhancing the power density of the charger. Its resonant operation allows soft-switching across the entire load range, minimizing switch losses, making it an ideal choice for high-frequency and high-power density designs, especially within a certain range of output voltages with improved EMI characteristics.

Since current after rectification in switch-mode power supplies often passes through large filtering capacitors, resulting in capacitive loads, it generates significant high-order harmonics, leading to pollution and interference. Hence, engineers began incorporating PFC circuits into switch-mode power supplies. Specifically, power supplies exceeding 75-85W are mandated to include PFC to improve power factor and correct load characteristics. PFC is divided into passive and active types. Passive PFC uses a large inductor for series compensation, but its main drawbacks include its large size and low efficiency.

With rapid advancements in semiconductor devices, active PFC has become mainstream. Active PFC utilizes a controller, MOSFET, inductor, and diode to form a boost circuit, known for its small size, wide input voltage, and excellent power factor correction effects. Active PFC achieves power factor correction based on the phase difference between voltage and current by driving the MOSFET to boost and rectify the main capacitor's charge.

Moreover, for LLC architecture to perform ideally, both input and output voltages must be fixed. The PFC circuit can stabilize rectified pulsating DC, supply power to the LLC, and perform power factor correction, meeting the working environment requirements of LLC architecture. In high-power-density adapters, the use of active PFC circuits in combination with LLC can reduce high-voltage filter capacitor sizes, reducing size and improving adapter power density.

ChargerLAB has compiled several popular PFC + LLC combo controllers available in the market, as listed below. Let's now delve into the parameters and features of each controller.

Twenty LLC Controllers for High-Power E-Bike Chargers: ChargerLAB Analysis-Chargerlab

The following manufacturers are listed alphabetically.

Chip Hope

LP9961AA

Chip Hope LP9961AA is an LLC controller with high voltage half-bridge driver. It supports 600V high-voltage gate drive, allowing the use of minimal peripheral components to achieve an efficient and reliable LLC resonant system. Adaptive dead time control can greatly improve system efficiency. It can simultaneously achieve high efficiency under light load and low standby power consumption under no load.

LP9961AA outputs a stable voltage through the internal LDO controller, which can directly power the external PFC controller. It integrates multiple protection mechanisms including input over/under voltage protection, output overvoltage protection, overcurrent protection, and over-temperature protection.

LP9962AA

Chip Hope LP9962AA is a PFC and LLC controller with high voltage half-bridge driver. It supports 600V high-voltage gate drive, allowing the use of minimal peripheral components to achieve an efficient and reliable LLC resonant system. Adaptive dead time control can greatly improve system efficiency. It can simultaneously achieve high efficiency under light load and low standby power consumption under no load.

LP9962AA adopts its patented detection method and algorithm, and the LLC system can achieve both constant voltage and constant current working states. It adopts CCM control mode, fixed frequency working mode when overloaded, and reduced frequency working mode when lightly loaded.

LP9962AA has multiple protection mechanisms integrated inside. The LLC part includes input over/under voltage protection, system output over/under voltage protection, output over current protection, and over temperature protection. The PFC part has inductor over-current protection, over-power limiting, input under-voltage protection, output over/under-voltage protection, over-temperature protection, etc. LP9962AA adopts SOP20 package.

FANTASTICHIP

FAN6899

FANTASTICHIP FAN6899 is a resonant controller chip dedicated to half-bridge LLC topology. It integrates 700V half-bridge driver, has -1.2A/2A current-sinking capability, a built-in high-precision oscillator, and operates at up to 500KHz frequency. It works in Burst mode at light load, which effectively reduces switching loss and improves light load efficiency. It has multiple protection functions, including current hysteresis type BIBO, two-level OCP protection, etc., which can provide more comprehensive overload and protection functions. It adopts SOP-16 package.

FAN6886&FAN6888

FANTASTICHIP FAN6886 & FAN6888 is a high-performance half-bridge LLC resonant controller chip, which adopts hybrid dual-cycle control technology to achieve the simplification of loop compensation and the rapidity of dynamic response. It has an automatic dead-time adjustment function and can achieve zero voltage switching (ZVS) under full load, effectively improving energy efficiency and system stability. FAN6886 & FAN6888 also have capacitive zone protection working function, and intermittent working mode control not only improves light load efficiency but also significantly reduces noise.

The control parameters of FAN6886 & FAN6888 can be programmed through the graphical user interface (GUI), and differentiated parameter control can be performed according to different application scenarios. Its peripheral circuit design is simple, and no Vcr adjustment sampling circuit is required, which simplifies the design process and can effectively reduce development costs. It can easily achieve the current soft start, further ensuring the stable operation of the system. It can easily achieve the current soft start, further ensuring the stable operation of the system.

It integrates 12-bit ADC and 64-byte MTP and has powerful data processing and storage capabilities. It has Brown in/out, output overvoltage protection, output under-voltage protection, and 3-level overcurrent protection. It meets strict energy efficiency requirements such as 80+, Energy Star, and COC V5 Tier2, and is suitable for high-power adapters, TVs, LED street lights, PC power supplies, etc. When used with the FAN663x, the FAN6886 & FAN6888 can even achieve a standby power consumption of less than 100mW without the need for an auxiliary power supply.

Infineon

ICE2HS01G

Infineon ICE2HS01G is a high-performance resonant controller chip designed for half-bridge LLC resonant converters. It is equipped with the synchronous rectification driver.

It adopts 20pin DSO package. It supports a switching frequency range of 30kHz to 1MHz with an adjustable minimum switching frequency and high-accuracy frequency setting.

It has an adjustable high-accuracy dead time, providing excellent stability and reliability to the system. The support of synchronous rectification makes the chip suitable for various half-bridge LLC resonant converter operation modes, while the internal and external disable functions increase the flexible control of the system.

ICE2HS01G has protection functions including main power input under-voltage protection, three levels of overcurrent protection to improve dynamic performance, open-loop/overload protection, etc. Adjustable blank time and restart time, as well as adjustable over-temperature protection with lock-off function, ensure the safety of the system to the greatest extent.

IDP2308

The Infineon lDP2308 is a multi-mode PFC and LLC controller combined with a floating high-side driver and a startup cell. Only a minimum of external components are required with the low pin count DSO-14 package. The integrated HV startup cell and advanced burst mode enable to achieve low standby power.

It supports synchronous PFC and LLC burst mode control, with configurable PFC drivers supporting multiple modes. It boasts higher efficiency and power density, outperforming LLC+traditional MOSFET combinations. Additionally, it supports configurable protection functions, keeping peripheral components minimal.

Infineon IDP2308's built-in processor allows programming via dpVision software through a half-duplex UART interface, configuring PFC and LLC parameters, and storing them in the built-in one-time programming memory.

Kiwi Instruments

KP2591(A)

Kiwi Instruments KP2591(A) is a resonant switching power supply controller based on a half-bridge LLC resonant converter. It integrates a half-bridge driver and can output a complementary drive with a 50% duty cycle to directly drive the power switch tube.

It integrates high voltage startup, AC power failure detection, and X capacitor discharge functions, a built-in high-precision VCO oscillator, and the maximum operating frequency reaches 350kHz. It integrates the function of adaptive dead-time control to ensure zero voltage turn-on (ZVS) of the power switch tube, thus improving the system efficiency. It integrates capacitive zone protection to avoid bridge arm shoot-through and hard switching, improving system reliability. It can also enter low standby mode through external signal control, reducing the standby loss of the system.

KP2591(A) has protection functions, including VDD overvoltage/under voltage protection, VBT undervoltage protection, AC overvoltage and input under voltage protection, overload protection, resonant cavity overcurrent protection, output overcurrent protection, capacitive area protection, SEL pin open short circuit protection, overheat protection, etc. It adopts SOP-16 package.

This is the application circuit diagram of Kiwi Instruments KP2591(A).

MERAKI

MK2199

MERAKI MK2199 is an LLC controller with high voltage half-bridge driver. It can be used with MK1620/1 to achieve efficient and reliable LLC design, and the adjustable dead time increases the flexibility of the system application.

It provides a CSS pin that provides a soft-start programmable function, allowing the user to set the soft-start time by changing an external capacitor.

Under light load conditions, MK2199 will automatically enter burst mode operation to reduce the loss of system switching devices. If the first level of protection is not sufficient to control the primary current, a higher level of over-current protection (OCP) will lock out the chip. The combination of the two provides comprehensive protection against overload and short circuits.

MK2189 Series

MERAKI MK2189/L/D is a half-bridge LLC resonant controller that can be used with LLC SR controller MK1620/1 to achieve high efficiency and high-reliability LLC design.

The MK2189 series achieves output voltage regulation by adjusting the operating frequency. The adjustable dead time increases system flexibility, and the CSS pin provides a programmable soft-start function, allowing the user to set the soft-start time by changing the external capacitor. At startup, the switching frequency starts from a programmable maximum value and gradually decreases until it reaches a steady-state value determined by the control loop. This frequency variation is nonlinear to minimize output voltage overshoot, and its duration is programmable.

Under light load, MK2189/L/D will automatically reduce the switching loss of system equipment and can suppress noise. If the first level of protection is not sufficient to control the primary current, a higher level of over-current protection (OCP) will lock out the chip.

The MK2189 series has a wide VCC voltage range of up to 26V, of which the MK2189D can adjust the dead time from 250ns to 1us. The operating frequency is up to 500KHz, with 0.3A drive current and 0.8A pull-down current, which can meet various power supply requirements. It adopts SOP-16 package. It can be applied to AC/DC adapters, high-power density DC/DC converters, server centers, LCDs, and other fields.

MERCHIP

M3010

MERCHIP M3010 is a bridgeless PFC+LLC controller digital controller chip.

Features:

• Single-channel low inductance, single-channel ripple is large, and the ripple coefficient is less than 0.3 after interleaving

• Single-channel current CBC and OST protection, CBC handles grid anomalies and will not trigger shutdown by mistake. In extreme cases, OST can protect the hardware

• Comprehensive protection for software RMS over-current, RMS over-voltage, RMS over-power, temperature, etc.

• The software introduces feedforward duty cycle and current sampling DCM calibration and independently determines CCM and DCM modes to improve light load THD

• Turn off one phase when the light load is low to improve light load efficiency

• Dynamic current sharing between two phases ensures that the current in both paths is consistent

• The voltage loop fast loop function ensures the stability of the bus voltage after the sudden load

• Switching frequency jitter can reduce EMI spectrum spikes

• Current CBC protection and input feedforward can ensure reliability in the event of power grid anomalies

•Software power frequency notch filter filters out 100hz ripple, which can increase the voltage loop bandwidth

• The control loop is the output voltage loop and output current loop, adopting dual-loop competition mode

• The circuit control adopts PFM+PWM mode, and the hiccup mode is used for extremely light load to improve efficiency

• Use variable dead time to balance reliability and efficiency

• Closed loop slow start to avoid overshoot, good adaptability to different characteristic loads

• Provide multiple protection mechanisms, including over-voltage and under-voltage protection, multi-level over-current protection to improve dynamic performance, overload protection, over-temperature protection, and other protections, and configurable restart time to provide flexible application

• External communication ports use SCI, CAN, SPI, etc.

MPS

HR1200

MPS HR1200 integrates a digital PFC controller and a half-bridge resonant controller. It requires very low power under no-load or ultra-light-load conditions, complying with the energy-using products (EuP) Lot 6 and 5th Edition's Tier 2 specifications.

Its patented average current control scheme for PFC operates in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) based on transient conditions of input voltage and output load. The IC exhibits excellent efficiency and high-power PF under light-load conditions. When operating in CCM, the controller can be used for applications up to 500W. The half-bridge LLC converter achieves high efficiency through zero-voltage switching (ZVS).

It also integrates a high-voltage current source within the IC for startup, eliminating the need for traditional startup resistors or external circuits.

HR1203

HR1203 is another high-performance controller integrating an advanced digital PFC controller and a half-bridge LLC resonant controller. Under no-load or ultra-light-load also meets the energy-using products (EuP) Lot 6 and 5th Edition's Tier 2 specifications.

Its PFC uses an average current control scheme based on transient conditions of input voltage and output load, operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM). Additionally, the IC demonstrates excellent efficiency and high power factor (PF) under light-load conditions.

To enhance immunity to disturbances, HR1203 incorporates multiple programmable digital filters for critical signal filtering. Moreover, it features comprehensive protection functions, including over-temperature shutdown protection, open-circuit protection (OLP), over-current protection (OCP), over-voltage protection (OVP), and under-voltage protection/startup.

HR1211

MPS HR1211 is a multi-mode PFC and current-mode LLC integrated controller. Traditional chips would require 2-3 chips to achieve this function, resulting in significant differences in cost and sophistication. Notably, it can be programmed via the UART interface. Its built-in energy-saving technology optimizes HR1211 efficiency across the entire operating range. Furthermore, it can operate in a hybrid CCM and DCM working mode.

The MPS HR1211 integrates the PFC controller and LLC controller into one package.

HR1211 employs a digital control scheme with multiple independent ADCs for detecting input voltage, PFC output voltage, LLC feedback voltage, and PFC peak switch current. It supports various comprehensive protection measures such as thermal shutdown, PFC open-loop protection, overvoltage protection, overcurrent limitation and protection, and over-power protection, among others. Notably, its standby power consumption is <100mW. Additionally, it supports high-voltage startup and intelligent X-cap discharge, with a PFC operating frequency of up to 250kHz.

NXP

TEA2016AAT

NXP TEA2016AAT comes in a thin and narrow SO16 package, integrating high-voltage startup, LLC, and PFC controllers along with their respective drivers.

The chip employs valley/zero voltage switching to minimize switch losses, maintaining high conversion efficiency across the entire load range while meeting the latest energy-saving standards with standby input power <75mW. TEA2016AAT also features comprehensive protection functions including undervoltage protection, over-power protection, surge protection, and more.

NXP TEA2016AAT is a digitally configurable LLC and PFC combination controller for efficient resonant power supplies. It integrates an LLC controller and PFC controllers operating in DCM and QR modes, enabling the construction of complete resonant power supplies. Furthermore, this chip adopts a digital architecture, allowing adjustments to LLC and PFC controller operation and protection settings during development.

The combination of TEA2016AAT with TEA1995T easily achieves 90-500W power with minimal external components. This comprehensive system maintains very low standby input power (<75mW) across the entire load range and complies with energy efficiency regulations such as Energy Star, the US Department of Energy, the EU Eco-design Directive, and the EU Code of Conduct.

TEA2017AAT

NXP's latest TEA2017AAT is a digitally configurable multi-mode PFC+LLC integrated controller. Compared to TEA2016AAT, its PFC supports CCM operation mode.

The configured PFC can operate in DCM/QR, and CCM fixed frequency mode to optimize PFC efficiency, constructing a complete resonant power supply with simplified power design and minimal component count, housed in a narrow body-width SO16 package.

Its digital architecture is based on a high-speed configurable hardware state machine ensuring very reliable real-time performance. The configurations can be fully secured to prevent unauthorized copying of the proprietary TEA2017AAT configuration content.

In contrast to traditional resonant topologies, the TEA2017AAT shows a very high

efficiency at low loads due to the LLC low-power mode. This mode operates in the power region between continuous switching (also called high-power mode) and burst mode.

TEA1716T

NXP TEA1716T is an integrated half-bridge LLC+boost PFC combination controller featuring intermittent frequency operation mode, compliant with EuP lot 6, suitable for LCD TVs, laptop adapters, desktops, and all-in-one power supplies.

Here is all the information about the NXP TEA1716T.

Powerforest

PF6771

Next is Powerforest's PF6771, a PFC and dual-feedback LLC integrated digital controller capable of outstanding performance and powerful features, meeting the needs of applications with two fixed outputs below 250W.

In the dual-feedback LLC architecture, NMOS and PMOS correspond to different outputs; for instance, in a TV system, PMOS corresponds to the system's 12V/5A switch, while NMOS is the backlight 130V/1A switch. Through their duty cycle ratio variation, PF6771 meets the wattage requirements of two different outputs, reducing efficiency losses in the primary backlight boost and additional power components, enhancing efficiency, and saving costs.

Its PFC operates in BCM mode and employs digital compensation design without external PFC compensation networks, effectivelycompensating for power factor and harmonic distortion. The LLC adopts current mode control. Additionally, it has dedicated pins for standby mode control, providing flexibility and control options.

Silergy

SY5055

Silergy SY5055 is a highly integrated PFC and LLC combined controller, consolidating the functions of separate PFC and LLC devices, reducing component count, and simplifying design.

With a single chip, SY5055 provides PFC and LLC control signals simultaneously.

SY5055 supports high-voltage startup, integrates valley detection, offers PFC undervoltage, overvoltage, and overload protection, supports X-cap discharge, and features compact SOP16 package with various output protections.

ST

STNRG011

STMicroelectronics' STNRG011 is a digital multi-mode PFC+time shift LLC controller, featuring an integrated 800V high-voltage startup circuit, input voltage detection, and X-cap discharge function to reduce standby power consumption. Its built-in PFC controller supports input voltage feedforward, THD optimization, and frequency limitation, operating in enhanced fixed-off-time mode.

It offers a complete set of PFC protection, convenient timing control for resonant half-bridge, enhanced burst mode for quick bursts, and a comprehensive half-bridge protection function. It can be used in open-frame power supplies, flat-panel TV power supplies, PC power supplies, and adapter applications.

STNRG011 uses an SO20 package with a block-oriented pin design that separates high-voltage and drive pins from sampling pins, facilitating circuit optimization. It features an 8-bit digital core control, digital algorithms, and hardware simulation circuits. The chip has built-in ROM memory for algorithm storage and supports UART pin communication for monitoring functions.

This is the application circuit diagram for STNRG011, where a single chip achieves complete PFC+LLC control. The chip is controlled by a digital core, and multiple key parameters are programmable. It features comprehensive built-in protection functions and supports configuration protection through the chip's internal memory. The inclusion of the digital core significantly reduces the difficulty of power supply development and debugging.

TI

UCC29950

TI UCC29950 is a PFC and LLC combined controller that provides comprehensive control functions for AC-to-DC converters with CCM boost power factor correction (PFC) and LLC transformers. The controller is optimized for ease of use. Its proprietary CCM PFC algorithm enables the system to achieve high efficiency, smaller converter size, and high power factor.

It includes a startup control circuit using an internally powered MOSFET in depletion mode to minimize external component requirements and help reduce system implementation costs. To further reduce standby power consumption, it integrates an X-cap discharge circuit. It features a complete set of system protection functions, including AC line dropout, PFC bus under voltage, PFC and LLC overcurrent, and thermal shutdown.

Summary of ChargerLAB

With the increase in fast charging power and the maturity of the secondary synchronous rectification buck converter, the high-efficiency and small-volume LLC architecture has been given the conditions to show its prowess in fast charging. The LLC architecture replaces the PFC+flyback topology in high-power PD fast charging. Combined with GaN and SiC components, the operating frequency is greatly improved, which can achieve higher conversion efficiency and power density.

In addition, the application of LLC architecture is not limited to e-bike chargers, it also has broad application prospects in other fields that require high power density and high efficiency. For example, high-power server power supplies, industrial power supplies, etc. can all benefit from the high-efficiency performance of LLC architecture.

Twenty LLC Controllers for High-Power E-Bike Chargers: ChargerLAB Analysis