Powering Next Generation Cores - ISL6812x/ISL6813x Overview
In this presentation, I will be introducing the ISL6812x and ISL6813x family of digital multiphase controllers targeting infrastructure power applications. This family of devices supports the latest PMBus 1.3 specification.
We have an expanding portfolio of power products, including a complete family of both analog and digital power modules to make it easier for customers to take advantage of the latest advances in power management in their systems. With the launch of our digital multiphase controllers, Intersil offers a full market solution for any processor, SOC, graphics card, and FPGA in the market, backed by a full portfolio of point-of-load and other power management building blocks, which includes DrMOS and Smart Power Stages (SPS).
The latest generation multiphase controllers feature a full digital compensator. This offers power designers unprecedented design flexibility with no external compensation, as device tuning is all managed digitally using our powerful and intuitive PowerNavigator software.
By leveraging Intersil's innovative synthetic current control architecture, the user can quickly realize a complete power solution in under 30 minutes vs. spending days managing complex RC Tables when using competing analog control solutions in the market.
In this presentation, we'll run through the differentiating features of this exciting new family or products, discuss target applications, and showcase the available design materials and collateral.
Benefits of Digital Multiphase
A digital multiphase controller provides an improved system with greater performance and optimization vs. traditional competing analog controller solutions in the market.
Due to the nature of being a full digital implementation, all the device level tuning and configuration is achieved in software using the PowerNavigator software. The highly flexible digital design enables fastest time to market, as an entire power solution can be realized in minutes vs. spending days managing complex RC tables and board re-work.
Power density is increased thanks to the on-chip NVM, non volatile memory, for storing user configuration settings. The Intersil digital multiphase controllers can store up to eight unique configuration settings per device. This allows end users to make changes as needed for deployed systems without recalling back to swap out controllers or hardware.
With full telemetry supported, which includes features like current information per phase, realizing full system control and monitoring has never been easier. Additionally, the power engineer can take advantage of Intersil's unique digital current modulator, which supports lossless input current sensing. This further simplifies the design and minimizes BOM content at the system level.
At the heart of our control loop is our patented synthetic current modulator. In the next few slides we will review the underlying benefits of Intersil's full digital implementation, which leads to fastest transient response and lowest output capacitance vs. the competition.
Digital Multiphase: Complete Solution
The ISL99227 Smart Power Stage consists of integrated drivers and power MOSFETs, and includes integrated differential current and temperature reporting. This eliminates complex DCR sensing networks in the system and achieves a compact design. With multiple interface options supported, a power designer can realize a full system solution anywhere between one phase and 14 phases by leveraging Intersil's full portfolio of power stages and phase doublers.
With full configuration achieved using the PowerNavigator GUI software, the Intersil digital multiphase regulator is able to meet the needs of any modern microprocessor, ASIC, SOC or FPGA design.
ISL681xx Technical Highlights
In the next section, we'll cover the technical highlights of the ISL681xx family of digital multiphase controllers.
ISL681xx Digital Multiphase Controller Block Diagram
This is a platform overview of our family of new generation multiphase controllers. It features a fully digital linear current modulator with up to two outputs, namely X and Y. Two different device configuration options are available, up to seven phases across two outputs in a 48-pin 6mm x 6mm package, and up to four phases across two outputs in a compact 40-pin 5mm x 5mm package.
At the heart of this family of digital multiphase controllers is our patented synthetic current modulation technology. We use the synthetic current that is generated cycle-by-cycle for high frequency current balancing and to support the fastest transient response vs. any competing solution in the market.
With only synthetic current entering the loop, the user can realize a noise-free, full bandwidth linear loop using our digital modulator technology to achieve fastest transient response. Competing current mode enabled solutions rely on a second current loop to support current balancing, which adds latency in the design and subsequently impacts transient response time.
The full digital compensator enables adaptive "on-the fly" loop tuning using the PowerNavigator software, therefore eliminating external RC components typically found in competing designs. With on-chip NVM, the user has the option to store up to eight different device configurations, each accessible via a pin strap resistor.
The full digital controller family of products supports a comprehensive telemetry and fault management system to enable highly reliable designs. Features such as a Black Box to record full telemetry and fault status bits during a catastrophic shutdown enable a user to quickly troubleshoot a deployed system.
The controller family supports the full industrial temperature range, and supports all major standard interfaces to power any microprocessor, SOC or FPGA solution in the marketplace, and is complemented by our growing portfolio of power stages like the ISL99227, which is a 60A Smart Power Stage with integrated current and temperature sense.
Target Applications for Infrastructure Power
Shown here are the target applications for the infrastructure power products. These controllers are targeted at anyone who is using an FPGA, ASIC or network processor. Example vendors include Xilinx, Altera, Broadcom, IBM, Qualcomm, and Cavium. As far as end-market applications, both controllers make excellent fits in wired infrastructure applications, including routers and switches; wireless infrastructure applications, including basestations; and datacenter driven applications like servers and storage.
Digital Multiphase Design Benefits: Flexibility
The multiphase controllers support the latest PMBus 1.3 specifications, this includes AVSBus, known as adaptive voltage scaling bus. The AVSBus is an "open standard" defined by the System Management Interface Forum, for the purpose of adaptive voltage scaling for Non-x86 processor solutions.
The Intersil multiphase controller family offers unprecedented design flexibility, due to the nature of being a full digital implementation. The user has the ability to configure outputs and assign any number of phases across both or single outputs. The truth table on this slide captures just some of the different permutations of phase assignments that are available with this full digital implementation. For example, depending on the power solution need, a user could adopt a 4-phase controller and assign all phases to a single output, namely 4+0, or spread phase assignment in any combination up to four phases across both outputs, all configurable using PowerNavigator software and with zero external components.
Software Defined Everything!
Shown here are example screen shots taken from our PowerNavigator software used to configure and tune the device. Full device configuration is achieved in the software. The controller supports autonomous phase shedding, with adjustable current thresholds, all managed in software. This gives the user complete autonomy to adjust current thresholds to deliver maximum efficiency on their individual board design.
The full digital compensator enables on-the-fly loop tuning. The family of controllers, supports a dual-edge modulation scheme, which implies the controller can modulate both leading and trailing edges of the PWM pulse to respond to any transient event. Additional control knobs are available using PowerNavigator to filter out any noise and even pull in the pulse, with features like pulse advance to respond to a demanding load or transient event.
The variable duty cycle coupled with variable frequency of our digital modulator scheme and synthetic current control architecture enables us to respond to any load transient with precise voltage and current positioning. In short, with just seven simple screens using the PowerNavigator software, a user can realize a complete power solution in minutes and eliminate board re-work associated with managing complex RC tables that is evident in competing solutions in the market today.
Synthetic Current Control Loop
Shown here is the synthetic current control loop diagram unique to Intersil. On the left side is the voltage loop, which supports a front-end ADC. This enables all the loop tuning to take place in the digital domain. The feature that differentiates our controller loop solution vs. all competing solutions in the market is the implementation of synthetic current on a per phase basis. This patented design ensures a single linear feedback loop that is inherently current controlled.
The implementation of a full digital linear loop with zero latency offers tremendous benefits, which includes a noise free, full bandwidth solution delivering fastest transient response. The zero latency loop response, unique to Intersil only, enables power designers to realize lowest total cost of ownership benefits by supporting the lowest output capacitance for any power design.
Synthetic current supports cycle-by-cycle calibration and corrects for removal of error due to component aging and thermal. This ensures precise delivery of voltage and current across the full load. Moreover, with only synthetic current entering the loop and implemented on a per phase basis, this allows robust current sharing per phase. So regardless of the load condition, the phase currents are always balanced.
Synthetic Current Control Loop Advantages
In summary, Intersil's synthetic current control loop architecture implemented on the new generation multiphase controllers offers significant benefits vs. competing solutions.
The linear control loop implementation offers a noise free, full bandwidth implementation with one third lower output capacitance vs the competition. This not only delivers total cost of ownership savings, but offers substantial PCB savings, which is becoming a critical factor in modern space-constrained power designs.
The full digital implementation enables full device configuration and on-the-fly tuning, achieved using the intuitive PowerNavigator GUI design. Leveraging sophisticated control of the loop in software speeds up time to market and eliminates board re-work associated with competing solutions in the marketplace.
Digital Multiphase: Black Box Capability
Black Box is a unique feature available on these controllers. When enabled using the PowerNavigator GUI software, it supports extensive fault logging and captures full telemetry data in the event of a catastrophic shutdown. Black Box, when implemented in fully deployed systems, can help reduce system down-time by aiding the user in troubleshooting the chain of events that caused the entire system to shutdown.
Through PowerNavigator software, the user can implement the Black Box feature either through RAM or NVM. Both options capture full telemetry and fault status information in the event of a shutdown.
Digital Multiphase: Power Density
Intersil's digital multiphase controllers supports OTP or one time programmable NVM memory to store user configuration settings. The family of devices supports up to 8 NVM slots.
It is important to recognize that once an NVM slot is used, it cannot be erased or reprogrammed. Moreover, multiple versions of the same Configuration ID can be stored in NVM; however, the controller will always load the most recent version of the configuration.
At start-up, an external pin strap resistor is used to tell the controller, which Configuration ID to load. The released datasheets contain information on pin strap resistors available for the eight slots.
Example Configuration Stores
This slide illustrates how Configuration IDs are accessed during startup. In this example, two Config IDs are stored in OTP. Namely Config ID 1 and Config ID 4.
A 4+0 design is stored as "Config ID 1" using an 1800Ω pin strap resistor. Moreover, the 4+0 design is then updated, resulting in a new Config ID 1 store. Finally, a 3+1 design configuration is stored in Config ID 3 using a 3300Ω pin strap resistor.
As you can see in the memory allocation diagram in the middle, three OTP slots have been used. Moreover, it is important to recognize that during startup only the latest Config ID 1 value will be loaded if an 1800Ω pin strap resistor is used. Subsequently, a 3300Ω resistor would load the configuration stored in Config ID 4.
Intersil Smart Power Stage Overview
Intersil has developed a full range of power stages supporting various current ratings to meet any ASIC, SOC, FPGA, or graphic card power rail requirements. When designing with Intersil's multiphase controllers, the ISL99227 60A Smart Power Stage is an excellent co-sell opportunity.
Unlike competing solutions that support a 20V lateral FET process that pose a reliability risk, especially in key server and telecom applications, the ISL99227 Smart Power Stage supports a 25V trench FET design to deliver excellent immunity to voltage spikes and mitigate avalanche conditions.
The large Copper pads for GND and Vin result in low thermal resistance vs. competing monolithic designs that support flip chip on lead packages. The dual side cooling package coupled in a proprietary 5mm x 5mm package, designed to minimize packaging parasitics, deliver excellent efficiency across the full load, thus making it ideal for high current applications such as servers and infrastructure power.
With integrated current and temperature sense reporting, with 3% accuracy over line, load and temperature, the ISL99227 simplifies the powertrain design by eliminating complex DCR networks and delivering an ultra-compact power solution for space constrained designs.
What is AVBus?
As highlighted earlier in the presentation, AVSBus or adaptive voltage scaling bus is an extension of PMBus v1.3.
AVSBus is an "Open Power" standard devised by the System Management Interface Forum (SMIF) of which Intersil is a member. With Intel and AMD having their own high-speed interface to connect to their x86 processors, the power community developed AVSBus as a competing proprietary-free open standard to facilitate point-to-point communication between a host processor and a controller at up to a 50MHz bus speed.
AVSBus has now become the de facto standard across many OEM driven microprocessor and network processor designs. By taking advantage of the high-speed bus interface, OEMs can now deliver power efficient processor solutions in the marketplace and minimize wasted energy associated with propagation delays, as illustrated in this slide when using a standard PMBus approach.
Intersil is a market leader with the AVSBus implementation available on the ISL68137 and ISL68134 controllers. As such, the Intersil solution has been implemented exclusively in several reference designs across multiple OEMs, spanning server and network processor designs.
Digital Multiphase Product Matrix
This slide captures the product matrix for infrastructure power products. The ISL68134 and ISL68137 are two controllers available that support AVSBus. The ISL68127 and ISL68124 controllers, support latest PMBus v1.3 specification. All controllers captured in this table support dual outputs and phase assignments are fully configurable using PowerNavigator software.
Example Application FPGA Rails
This design example showcases how the Intersil family of digital power products fits in a Xilinx, Kintex or Virtex class FPGA design. For the high current core rail, Intersil offers digital multiphase controllers that make it an excellent fit. For the other FPGA auxiliary rails, DDR4 memory rails, and system level 3.3V and 5V rails, the ISL68200/01 are excellent solutions.
This next section covers development tools available for our controller family.
Digital Multiphase Development Platform Overview
Intersil has developed a broad range of evaluation boards to facilitate both PMBus and AVSBus testing across both 4-phase and 7-phase controllers.
Development Board Example
Shown here is an example AVSBus evaluation board supporting a 3+1 configuration. All boards are fully compatible with PowerNavigator software and include a built-in load hitter to facilitate transient testing. As shown in the picture, all AVSBus boards come with a PMBus and AVSBus dongle. The AVSBus dongle is used to facilitate AVS testing. All boards including the one shown support ATX supply or separate 12V and 5V bench supply connectivity.
Full AVSBus and PMBus datasheets are available online. Evaluation boards are available for purchase for both up to 4-phase and up to 7-phase controllers, and include the USB to PMBus adapter and USB to AVSBus adapter. Download the PowerNavigator software from our website. All the controllers are offered in bulk and reel options.