Introducing Richtek VCORE Solutions

Did you ever wonder what kind of power supply systems are driving the processors in your notebook or desktop PC? VCORE regulators are no ordinary voltage regulators: They have to deliver more current than typical welding equipment, have to deal with huge load transients having extreme dI/dt, they must be able to change the output voltage dynamically and control the CPU voltage within very narrow tolerance bands. At the same time they have to have good efficiency at both high load and light load conditions. VCORE controllers have a direct communication link with the processor and are normally developed to work with specific processor types or families. Richtek has been developing VCORE controllers for over 10 years and has a wide range of VCORE solutions and PMIC’s for CPU, GPU and APU processor families of Intel and AMD. It is quite possible that the Desktop PC or Notebook that you are using is

VCORE Solutions

A typical VCORE regulator application consists of a VCORE buck controller, multi-phase power stages for delivering the high core rail current, CPU core voltage sense, individual phase current sense, temperature sense and a serial interface between the CPU and the VCORE controller. Controller SET pins are used to program preset settings to match the particular CPU platform requirement. The CPU can send serial commands to the controller like core supply voltage changes or different power save states, and can also read controller register values like current consumption and operating temperature.

One of the main challenges of VCORE regulators is the load transient capability. 80% load steps with 100nsec rise times are common and the regulator needs to have excellent transient response to avoid core voltage undershoots or overshoots which could cause CPU crash or damage. Richtek VCORE controllers use several methods to improve output accuracy, achieve excellent transient response and allow easy programming of load line:

CCRCOT topology (Constant Current Ripple Constant On Time) uses the advantages of COT fast response time and at the same time adjusts the on time to achieve constant current ripple over the entire input voltage, output voltage and load range. This system maintains a constant output ripple which improves voltage accuracy, and improves efficiency at lower load and lower input and output voltage conditions.

Programmable QR (Quick Response) helps to improve load transient response by temporarily bypassing the normal voltage regulation loop when a sudden load step is encountered. A QR trigger can instantly activate all phases with a specific (programmable) pulse width, thereby maximizing the energy transfer during a load step, which minimizes the output voltage undershoot.

G-NAVP (Green Native Automatic Voltage Positioning): Automatic Voltage Positioning is also called load line or voltage droop. It basically means that the converter output will automatically reduce its output voltage at higher load current as illustrated below. Although this seems counterproductive to good load regulation, it actually helps to create extra headroom for the output voltage under and overshoots during load transients and reduces CPU temperature at high load.

Load line values are normally dictated by the CPU makers. Richtek uses a proprietary finite gain error amplifier concept to create a natural and easy programmable load line, while at the same time simplifying the error amplifier compensation.

For more information, including an overview of Richtek VCORE design tools and evaluation boards, please read the full application note Introduction to Richtek VCORE solutions.

Which Richtek VCORE controller should I choose?
Richtek VCORE controllers are divided into INTEL and AMD segments, then split into low power and performance groups. From there the parts are subdivided into different platforms. Richtek also provides high integration PMIC solutions, for a complete one-chip power solution for specific INTEL SoC’s. These are especially attractive in small form-factor applications and mobile applications requiring the lowest quiescent current in low power standby mode.

You can find Richtek VCORE parts by entering CPU specification, platform names and sockets on the VCORE selection page. You can also find system block diagrams of different Intel platforms on the Intel VCORE solutions page. For a full overview of Richtek VCORE solutions for Intel and AMD CPUs please download the Richtek VCORE product selection list.

Cannot find a VCORE regulator part? Due to the fact that Richtek VCORE parts are developed in cooperation with INTEL and AMD, some information will not be published on the Richtek website due to confidentiality reasons. If you would like more information on specific Richtek VCORE regulator parts or are looking for VCORE regulators for specific CPU platforms which are not shown on the Richtek website, please contact your nearest Richtek sales office.

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