Part Number: UCC5350-Q1
Other Parts Discussed in Thread: UCC5350, LMG5200
Tool/software:
Hi Team
Customer is planning to develop a GaN-based OBC, and switching frequency will reach to 500Khz,
1. they want to understand if UCC5350 can support 500Khz?
2. Is it the good choice for drive discreated GaN?
3. which parameter decides the highest switch frequency supported for a gate driver.
Hi Harry,
Usually, the switching loss of the FET and its limited heatsinking capacity set the maximum practical switching frequency.
The gate driver itself can switch at almost 25MHz unloaded. However, the D package has a 1W power limit also, and depending on the capacitor load, this too sets an upper switching frequency limit.
1. If the GaN FET can switch efficiently enough that 500kHz * (Eon+Eoff) < Max FET power dissipation, then yes, the UCC5350 will be able to support that output square wave frequency.
2. TI recommends integrating a GaN FET and a gate driver, such as LMG5200. This is due to the improved control over high frequency switching waveforms at the IC level, vs. the discrete level:
3. The limit of 25MHz comes from the propagation delay of the gate driver. If the input pulses are too short, they are filtered out by the on-off keying mechanism of the isolated gate driver. However, this is far beyond the limit at which you will be able to switch a GaN FET at a high current and voltage level.
Best regards,
Sean
