As I mentioned partly 1, the printed circuit board (PCB) location devoted to power administration is an immense constraint for system developers. Reducing converter losses is a vital requirement to make it possible for a portable awareness in space-constrained applications with restricted PCB property.
The capability to flexibly release a converter at a critical area on the board is also essential– take for instance a high-current point-of-load (POL) module, ideally located adjacent to a lots for smaller sized conduction decline and also far better load short-term performance.
Consider the power stage layout in Number 1 of a miniaturized form-factor dollar converter. As an ingrained POL component application, it uses an all-ceramic capacitor design, an efficient shielded inductor, vertically piled MOSFETs, a voltage-mode controller and a six-layer PCB with 2oz copper.
Figure 1: 25A simultaneous buck converter PCB design with application.
The major tenets of this layout are high power density and also reduced bill-of-materials (BOM) price. It inhabits an overall PCB location of 2.2 cm2 (0.34 in2), yielding a reliable current density per unit location of 11.3 A/cm2 (75A/in2). Power thickness each quantity at 3.3 V output is 57W/cm3 (930W/in3).
The regular strategy to attaining above ground power density is to enhance changing frequency. By contrast, you could attain miniaturization via tactical part option while retaining a fairly reduced switching regularity of 300kHz to decrease frequency symmetrical losses such as MOSFET changing loss as well as inductor core loss. Table 1 lists the necessary components for this layout.
Worth proposition of high-density PCB layouts
Clearly, the PCB is an essential (as well as often most pricey) component in a layout. The worth suggestion of a tactical and also thoroughly performed PCB design for a high-density DC/DC converter depends on:
● A lot more performance in space-constrained styles (lowered option quantity and also footprint).
● Decreased switching-loop parasitical inductance, contributing to:
○ Lower power MOSFET voltage tension (switch-node voltage spike) and also buzzing.
○ Decreased switching loss.
○ Reduced electro-magnetic disturbance (EMI), electromagnetic field combining as well as outcome sound trademark.
○ Bonus margin to endure input rail-transient-voltage disturbances, particularly in wide-VIN-range applications.
● Increased reliability and effectiveness (lower element temperature levels).
● Price financial savings connected to a smaller sized PCB, fewer filtering components and also the removal of snubbers.
● Distinguished styles supply a competitive advantage, capture customer attention, as well as rise profits.
It’s reasonable to state that PCB design specifies the performance inevitably achieved from a switching power converter. Of course, the designer is quite pleased to stay clear of plenty of hours of debugging time for EMI, sound, signal stability, and also various other concerns connected to a bad design.