1.7kV SiC ac-dc converter ICs now in surface mount

Author: EIS Release Date: Jun 24, 2021

Rohm has introduced surface-mount versions of its ac-dc converter ICs that include a 1,700V silicon carbide mosfet – opting for the 10.2 x 4.4 x 15.5mm TO 263-7L package, which can be automatically mounted in production.

 

BM2SC12xFP2-LBZ cct

Rohm SiC ac-dc BM2SC12xFP2-LBZ package

 

Called BM2SC12xFP2-LBZ, the series (table below) implements a quasi-resonant topology and is aimed at industrial auxiliary power supplies – for example 400Vac in, 24V 2A out.

 

“Evaluation board BM2SC123FP2-EVK-001 [below] using our BM2SC123FP2-LBZ IC delivers power up to 48W at 400Vac without any heatsink,” said Rohm.

 

 

Inside, the converter uses PFM (pulse frequency modulation) mode control with optocoupler secondary-side feedback.

 

 

Rohm SiC ac-dc BM2SC12xFP2-LBZ evalThe feedback pin, a third transformer winding and source current are all monitored (top diagram): SiC mosfet turn-off(on width) is controlled by the feedback pin and the source current. Turn-on (off width) is controlled by the third winding voltage.

 

“By setting maximum

frequency, PFM mode will control it to meet noise regulation,” according to Rohm.

 

Burst operation is used at light load stand-by consumption is 19µA.

 

Protections include Vcc under-voltage lock-out, Vcc over-voltage and per-cycle over-current – current detection resistors are external for flexibility. Soft-start is implemented.

 

Rohm SiC acdc BM2SC12xFP2-LBZ partsApplications are foreseen in the auxiliary power supplies within PLCs, inverters, AC servo drives, street lamps and commercial air-conditioning systems.

 

Samples are available now, with production scheduled for October.