tech.support@psbel.com

belfuse.com/power-solutions

BCD.00791 Rev. AN, 10-Aug-2021

Page 3 of 18

RCM Series

150 / 300 W DC-DC Converters

© 2021 Bel Power Solutions & Protection

Product Marking

Type designation, applicable safety approval and recognition marks, CE mark, pin allocation, and product logo.

Input voltage range and input current, nominal output voltage and current, degree of protection, batch no., serial no., and data code

including production site, version (modification status) and date of production.

Functional Description

The converters are designed as active clamp forward converters with a switching frequency of approximately 120 kHz. The built-in

diode acts as reverse polarity protection together with the external circuit breaker or fuse.

The circuitry providing the interruption time (opt. M) is located after the input filter.

The rectification on the secondary side is provided by synchronous rectifiers, in order to keep the losses as low as possible. The

output voltage control logic is located on the secondary side and influences the primary logic through magnetic feedback.

An auxiliary converter supplies all circuits with a stable bias voltage.

An output ORing FET is available (option Q) and allows for a redundant power supply system. If there are no external circuit

breakers, it is possible to order the converter with incorporated fuse (opt. F). Because this fuse is not accessible, a serial diode

provides reverse polarity protection (only with option F or M).

Opt. D encompasses an additional auxiliary connector and allows for output voltage adjust and a primary shutdown. An output

voltage monitor controls a relay with a change-over contact.

Vi–

Vi+

Vo–

JM194f

Auxiliary connector (only with option D)

Vo+

Auxiliary

converter

SD0

SD

PE

Opt. Q

Fuse

(option F)

OK0

+

Opt. M

Input

filter

Primary

control logic

¹ Series diode, only fitted with opt. F or M

² Bipolar suppressor diode with opt. F or M

³ Relay contact shown under normal operating conditions

and output voltage under regulation

1

Output

filter

OK2

Secondary

control logic

R–

R R

R+

Isolated

driver

NTC

OK1

2

3

Fig. 1

Block diagram