How to Resolve the “Heat and Frequency” Conflict in Modular Telecom Power Supplies? Engineering Selection Answer for 62mm SiC Modules

      Modular telecom power supplies require a single module to output 3kW~5kW within 1U/2U height. Conventional silicon-based IGBT modules usually have switching frequencies below 20kHz, making magnetic components bulky, and turn-off tail current causes significant losses. Chaoxing Semiconductor's 62mm standard package SiC MOSFET modules (1200V/200~600A, 1700V/200~400A) have mounting holes fully identical to those of mainstream IGBT modules. During upgrades, there is no need to redesign the heatsink flow channels or busbar structure; only the gate resistor and gate voltage need to be adjusted to raise the switching frequency from 20kHz to above 50kHz, greatly reducing the output filter inductor.

Why must modular telecom power supplies resolve the conflict between “heat” and “frequency”?

      The core conflict of modular telecom power supplies is that operators require high power density (3kW~5kW output within 1U/2U), while the low-frequency characteristics of silicon-based IGBTs force magnetic components to occupy a large amount of space; at the same time, hot-swap and redundant parallel architectures make the ambient temperature inside the cabinet as high as 90℃, leaving extremely limited thermal margin. The value of SiC modules is not simply to “replace” IGBTs, but to release frequency space and thermal margin at the same time.

Although conventional silicon-based IGBT modules have strong current-carrying capability, their switching frequency is usually below 20kHz, making it difficult to compress the size of PFC inductors and LLC transformers. Turn-off tail current further exacerbates switching losses, forcing thermal design to increase margins. As telecom power supplies evolve from “single large power supplies” to “modular, hot-swappable, redundant parallel” systems, these two constraints tighten simultaneously.

The engineering logic of 62mm SiC modules is to keep the package unchanged and change the physical characteristics of the device. Mounting dimensions are the same as those of mainstream IGBT modules, meaning telecom power supply manufacturers do not need to redesign heatsink flow channels or busbar structures, and the engineering risk of the upgrade path is controllable. The reduction in magnetic components brought by higher frequency directly serves the power density target within 1U height.

Which parameters of Chaoxing 62mm SiC modules directly address telecom power supply selection requirements?

      Three engineering characteristics correspond to the core demands of modular telecom power supplies—standard 62mm compatibility reduces upgrade and retrofit costs, low parasitic inductance design combined with laminated busbars suppresses high-frequency switching voltage overshoot, and SiC die high-temperature characteristics combined with a low thermal resistance package support continuous full-load output at 90℃ case temperature. Taking CG600F120MBX100 as an example, the 1200V/600A/2.7mΩ parameter combination targets rectification and bidirectional inversion scenarios in high-power centralized telecom power supplies.

Selection quick reference:

Representative model parameter comparison:

• CG200F120MBX100: 1200V/200A/8mΩ, for 3kW~5kW modular rectifiers, applications listed include UPS and inverters
• CG300F120MBX100: 1200V/300A/5.3mΩ, Rth(j-c) is only 0.12℃/W, suitable for bidirectional conversion in medium-power telecom power supplies
• CG600F120MBX100: 1200V/600A/2.7mΩ, for centralized high-power telecom power supplies and HVDC architectures

What can be gained at the telecom power system level when upgrading from silicon-based IGBTs to 62mm SiC modules?

      Three quantifiable system benefits—frequency increase reduces magnetic component size, efficiency improvement lowers heat generation and thus simplifies thermal design, and bidirectional conversion capability supports telecom base station “PV overlay + energy storage” scenarios. In a PV overlay power supply system, during the day PV supplies the load through module rectification and charges the battery; at night or during an outage, the battery discharges through the same module's inversion. Overall system conversion efficiency is improved by more than 2% compared with conventional silicon solutions.

Benefit in the frequency dimension: the upper limit of switching frequency for silicon-based IGBTs is about 20kHz, while 62mm SiC modules can raise it to above 50kHz. For a 3kW telecom rectifier, the core size and winding turns of the PFC inductor and LLC transformer decrease as frequency increases, and the overall volume of magnetic components can be reduced by about 30%. This is the physical basis for achieving 3kW output within 1U height.

Benefit in the thermal dimension: SiC modules have no tail current, and turn-off losses are significantly lower than those of IGBTs. At the same output power, the module's own heat generation is reduced, and the heatsink thermal resistance requirement is relaxed accordingly. For outdoor telecom power supplies designed to be fanless or use low-speed fans, this means increased margin for shell heat-dissipation fin height and thermal interface material specifications, while reducing dependence on cabinet air-conditioning cooling.

Benefit in the bidirectional conversion dimension: the trend of “PV overlay + energy-storage backup” in telecom base stations requires power supplies to have bidirectional energy flow capability. The high-frequency and high-efficiency characteristics of SiC modules allow the same power stage to switch between rectification and inversion modes without adding extra power conversion units. In conventional silicon-based IGBT solutions, this capability is limited by switching losses and topology complexity, making it difficult to implement economically.