DC/DC converters with programmable outputs for wide-bandgap applications
The R24C2T25 simplifies selction and evaluation of SiC components
Power Supplies I 25.07.2024
Providing precise gate drive voltages is crucial, especially for the latest generation of SiC devices. The programmable outputs of the R24C2T25 isolated DC/DC converter allow a range of devices to be evaluated and the most suitable voltage levels to be set for the best combination of system efficiency and safety.
The Problem
Broadband technologies such as SiC and GaN are on the rise. With every new generation, however, the demands placed on the components also change. For example, there are first, second and third generation SiC devices on the market from different manufacturers, and each generation requires a different combination of voltages to switch the component on and off. This presents a challenge both for the gate drivers and for the isolated DC/DC converters used to supply them. To ensure isolation, these converters usually use an internal transformer designed with a fixed transformation ratio. This supplies the appropriate bias voltage for the gate driver in use. One DC/DC converter is thus required to supply a SiC component with switch-on and switch-off voltages of +15 V and -8 V, while another is required to supply another SiC component with voltages of +15 V and -3 V. If both combinations are available as standard products, no problem. But if a new design of the DC/DC converter is necessary, this can affect the production schedule and require a new safety certification. Lower production quantities will probably also mean an increase in unit costs
Solution and Advantages
Figure 1: The R24C2T25 isolated 2W DC/DC converter simplifies the design of WBG gate drive bias supplies (source: Recom)
This is where the R24C2T25 isolated DC/DC converter presents a solution, allowing different types of SiC power transistors to be evaluated without having to make costly and time-consuming design changes.
As well as being able to choose between different SiC components, the programmability offers additional flexibility in the development phase. The switching voltage for a selected SiC component can be varied and a decision as to which voltage to use for switching can be made on the basis of empirical tests. By keeping the voltages within +/-1.5%, the risk of overvoltage and damage can be avoided.
Total available power is 2W up to an ambient temperature of 82°C and 2.5W up to 75°C, with derating-reduced power available up to the maximum package temperature of 125°C. The isolation of the R24C2T25 is 3kVAC/1min with ultra-low isolation capacitance of 3.5 pF and CMTI of ±150kV/µs. This makes the components suitable for supplying high-side gate drives with fast dV/dt and dI/dt power switching edge rates.
Additional advantages and features of the R24C2T25:
• Asymmetrically programmable outputs: Via external resistor networks, the outputs can be set to between +2.5 and +22.5VDC / -2.5 and -22.5VDC with a total positive-to-negative voltage of 18 to 25VDC – for example +15/-3V. They are suitable for IGBT, Si, SiC and GaN cascode gate drives.
• Comprehensive protective functions: The R24C2T25 features soft start, overvoltage and undervoltage lockout at the input, thermal shutdown, and overload protection at the output. Overvoltage and undervoltage lockout at the output also ensures that power components are not subjected to improper gate voltages. A power-good signal is provided with the ON/OFF control to put the converter into standby mode with a current consumption of less than 700µA.
• Advantages of surface mount technology: The compact 7.5x12.83mm 36-pin SSO package means higher packing density and correspondingly improved space efficiency on the PCB. Other advantages include greater efficiency and better EMI behaviour.
• Wide range of applications: Areas of application include industrial automation (motor controls and inverters), building and home automation, renewable energy (battery management systems, wind power, photovoltaics), data and telecommunications (computer centres, data centres, wireless data transmission), and infrastructure (traffic control, railways, commercial vehicles).
Providing precise gate drive voltages is crucial, particularly for the latest generation of SiC devices. The programmable outputs of the R24C2T25 isolated DC/DC converter allow customers to evaluate different devices and set optimum voltage levels for the best combination of system efficiency and safety. In addition, the surface mountable package offers several advantages, including optimised EMI behaviour, improved efficiency, and a smaller footprint.
At Schukat
Schukat electronic offers power supplies from a range of manufacturers, including MEAN WELL, RECOM POWER and Self Electronics. Schukat stocks around 6000 different types of power supplies and DC/DC converters in production quantities at its automated central warehouse in Monheim am Rhein, Germany.
As a distributor, they provide fast, competent support with direct contact persons, and also offer an expert field service team for on-site problem solving. Customers benefit from rapid processing of enquiries, availability of data sheets and samples, and variable delivery quantities, from samples to series production.