Power density and efficiency of quarter brick DC/DC converters

As is well known, the Intermediate Bus Architecture (IBA) is enabled in modern servers, workstations and telecommunications equipment by various isolated DC/DC converters called bricks. By providing a lower DC bus voltage, these bricks allow system designers to quickly build high-efficiency, high-density, point-of-load, non-isolated (POL) buck regulators for driving a variety of electronic loads, such as microprocessors, FPGAs. And ASIC's cross-system board. The task of building a POL regulator is simpler because the current step-down ratio is smaller. Recently, in the technical exhibition article "Higher Power, Efficiency and Density One-eighth Brick Converter" it shows that one-eighth brick converter is developing more power from the same standard 2.3 × 0.9 inches (58 × 23 The MM) package has higher efficiency, digital control, and lower cost. As a result, the power of these bricks and the function of the quarter bricks are significantly smaller than the eighth brick profile with a competitive price and higher efficiency and density. At the same time, brick manufacturers have increased the performance and power consumption of a quarter of bricks because the system board requires more power, faster response and higher efficiency. In addition, like the PMBus interface is added as a digital control. In the improvement of manufacturers from manufacturers such as Cui to improve quarter-bricks, GE's key power supply, Murata power solutions, Bühler power solutions, and Vicor, etc., this article will introduce how quarter-brick promotion to handle half-bridges And full brick mission.

Raise the standard

Wai Ge, for example, is pushing the power envelope higher while improving the efficiency bar. Recently, the company has squeezed output power to 850W from the first quarter brick size of > 98% peak efficiency. Part of Vicor's VIBrick® IBC series, the IB050Q096T70N1-00 provides maximum available power with unprecedented efficiency and transient response in the least amount of space. Available as a simple upgrade to an industry standard 5:1 fixed-scale converter, the IBC module operates from an input voltage range of 36 to 60 V with an input voltage range of 2250 VDC isolated from input to output. The module achieves very high peak efficiency at the same time (Figure 1). It is rated for power up to 80 A, but the input voltage range for the 850 W output is 55 to 60V. Similarly, for a 550 W output, the DC input range is 36 to 54 V. According to the supplier, the open frame structure of the 2.30 x 1.45 x 0.42 inch quarter brick module facilitates airflow underneath the module above. To reduce the temperature rise of downstream components. As a result, it produces the maximum available power in thermally limited systems, enabling designers to save valuable board space and achieve full-load operation with only 400 LFM of airflow at 65 °C. Each Vicor product data sheet, the IBC module uses a proprietary sinusoidal amplitude converter topology to switch at higher frequencies to increase power density and efficiency while reducing transient response time by a factor of 10, which saves Goed through the middle bulk capacitor bus.


Figure 1: Vicor's VI BRICK IBC 1/4 brick exhibits 98% peak efficiency at 55 ° C ambient temperature. Combined with its patented Solus power topology, Cui also drives the NQB series of 1/4 bricks designed to meet the power requirements of the rising power requirements of intermediate bus converters used in telecommunications systems and data centers. As part of the company's Novum hotel premium power portfolio, the NQB Series is capable of supporting up to 720W in the input voltage range of 36 to 60 VDC in a quarter brick footprint and 12 VDC output, while providing greater than 96% effectiveness. The NQB product will eventually support a wider input range and an output of 9.6 volts. Other features include the choice of DOSA footprint compatibility, remote on/off and load sharing capabilities.

digital control

For digital control, the vendor offers the NQB-D series, which uses 32-bit ARM microcontrollers with power-optimized firmware to maximize the efficiency curve of load conditions that differ greatly in flat and flat applications. In addition, the PMBus version 1.2 interface can be used for remote control and monitoring, as well as configuring brick output voltage, voltage margin, fault management, precise time delay acceleration, and start/stop. Similarly, GE's key power supplies have been incorporated into the company's high-powered pike line, which provides digital control of the quarter-brick package of the fully regulated DOSA standard. The PMBus Armed Barracuda Brick is designed to provide a 9.6 to 12 VDC intermediate bus voltage driven non-isolated point-of-load converter. With a 36 to 75 volt DC input range, the 12 VDC output QBDW025A0B rated 300 watts (Figure 2) output power. It supports a subset of the commands in the PMBus 1.2 specification. The supported commands are described in the detailed product data sheet. The PMBus programming controller parameters used can be stored as default for later use. The quarter brick QBDW025A0B contains non-volatile memory for storing configuration settings and scale factors.


Figure 2: GE's key power supply DOSA standard quarter brick QBDW025A0B, a member of the Barracuda series, rated at 300 watts of 12 volt DC output power. To achieve 96% or higher efficiency, the pike bricks will be rectified and innovatively packaged. Because the output is completely isolated from the input, it allows for a multi-polar configuration and ground connection. In addition, DC/DC converters reduce external filtering by incorporating input and output filtering. The output of the pike bricks is overcurrent protected, overpressure and overheating. For higher power requirements, the QBDW025A0B power module provides optional features for parallel operation. It provides an accurate, forced output voltage load regulation drop characteristic. According to GE, the output setpoint and droop slope are factory calibrated to ensure the best match of the load regulation characteristics of multiple modules. In order to achieve the load sharing requirements, the data sheet is a good explanation. Other options include thermal management and automatic restart after a base failure shutdown. Substrates used in natural convection and forced convection environments improve heat dissipation. In addition, it also allows the unit to be deployed where the substrate is connected to a large heat sink, or the cold plate conducts cooling applications.

Wider input voltage range

Under normal conditions, the input voltage range is 2:1 for brick converters, which means that the maximum operating voltage is approximately twice minimum. Typical examples are 18 to 36 V and 36 to 75. However, for environments where applications such as Murata Power Solutions and Bell Power Solutions can be deployed, the voltages offered can be quite different, and the manufacturer offers an ultra-wide-model input voltage range. In these products, the input range can be 3:1 or wider. A good example is Murata's quarter-brick converter UWQ-12/20-T48. Designed for wireless backhaul, a wide range of networks, and other telecom applications, it accepts input 18~60 VDC from a DOSA compatible open frame quarter of a quarter brick package only 58.4 x 36.8 Occupy provides 12 VDC at 20 A x 11.7 mm (2.3 x 1.45 x 0.46 inches). Offering precise load and line regulation, the unit ensures that the output voltage does not vary by more than ±1.25% depending on load changes. Typical efficiency is 92%, and up to three units can operate in parallel to provide redundancy or load sharing for higher output power (Figure 3). In addition to on/off control, remote, quarter-quarter brick converters provide overcurrent protection, over temperature, input undervoltage, and output short circuit. In addition, an optional base can be used for conduction cooling.


Figure 3: Murata's isolation of 1/4 brick can achieve a larger output current connection at the same time. In the UWQ series, Murata also added 1/4 brick and 4:1 input function. One such member is the UWQ-12/17-Q48 with a nominal 48 V input input range of 18 to 75 VDC. The fixed-DC output is 12 V at 17 A current. Other features include remote on/off control, DOSA-compatible pinout and form factor, rich self-protection, overvoltage protection, input undervoltage, current limit and thermal shutdown. Similarly, Bühler Power Solutions is ready to specify the UIQ to address 18 V wide DC input 75 V and produce DC output DOSA compatible 240W quarter brick series 12, 5, or 3.3 V UIQ48T20120, for example Provides 12 VDC, 20 A and over 92% efficiency. It is designed for operation in systems with limited airflow and increased ambient temperatures. In addition, the brick module uses a heat sink that provides an effective thermal interface for the cold plate and heat sink options (Figure 4).


Figure 4: Bell Power Solution "The DOSA-compatible quarter brick UIQ48T20120 is equipped with a heat sink to further enhance the thermal performance of the converter. In summary, the new standard power of the quarter brick DC / DC converter Density, conversion efficiency, and thermal performance add more functionality to the board as a result of which they are assigned to half and full bricks before being processed.