R24C2T25 datasheet(4/9 Pages) RECOM

4 / 9 page

Technical Data Sheet

DC/DC Converter

Rev. 2-2024

Page 4

2W / 21V-27VDC / 36 Pin SSOP Package

RxxC2Txx series / Power Module

www.recom-power.com

TRIM FUNCTION

Setting the main output - Single Configuration

Setting the second output - Dual Configuration

Defining RLIM

The VOUT+ to VOUT- output is the primary module output, regulated by the sensed voltage on FBVOUT+ pin. The VOUT+ to VOUT- voltage is sensed through

a voltage divider (R1 and R2). When FBVOUT+ voltage is below the turn-off threshold (approx. 10mV above the 2.5V reference), the power stage

operates, raising the output voltage. Once the output reaches the turn-off threshold, the power stage turns off, causing the voltage to drop due to

load current. When the output voltage falls below the turn-on threshold (approx. 10 mV below the 2.5V reference), the power stage is reactivated.

Precise voltage reference and hysteresis control ensure accurate regulation. For enhanced noise immunity, add a 330pF capacitor between FBVOUT+

and VOUT- pins, avoiding excessive capacitance to prevent output voltage ripple or stability issues.

For isolated gate drivers, VOUT+ to VOUT- provides the regulated total voltage with the midpoint as the reference. The COM pin regulates the midpoint

voltage for accurate positive and negative outputs based on FBVOUT+ feedback.

In Figure below, COM to VOUT- is monitored through R3 and R4 on FBVOUT-. A 330pF capacitor on FBVOUT- filters noise. Charging resistor activation,

controlled by FBVOUT-, raises COM to VOUT- voltage. After reaching the stop charging threshold, the charging resistor turns off. The discharge resistor,

with a 20mV hysteresis, is then controlled by FBVOUT-.

The COM to VOUT- regulator protects against prolonged high-side FET activation during a COM to VOUT- short. It monitors COM pin voltage, adjusting

the high-side FET duty ratio. If COM pin voltage is below 0.645V while FBVOUT- is under 2.48V, a 20% duty ratio control overrides normal hysteresis.

When COM pin voltage exceeds 0.73V, duty ratio control is disabled, and normal operation resumes.

When the device has been configured to dual configuration, the RLIM resistor is a true current limiting resistor. Set up the RLIM resistor as the maximum

load current (IOUT-_max) needed for VOUT- to COM path using following equation:

*(according to E96)

RLIM_internal = 30Ω

* IOUT-_max = depends on application

* IOUT-_max has been defined as 12mA for the target application

Recommended resistor values for common VOUT+:

Recommended resistor values for common VOUT-:

VOUT+

VOUT-

FBVOUT+

10µF

330pF

VOUT+

VOUT-

COM

FBVOUT-

RLIM

330pF

10µF

33µF

AGND

Calculation

Example

Example RLIM for VOUT-= 5VDC

Setting the main output (Vout+ to Vout-)

��

=(��+−��)

�� ×��2

Setting the dual output

��

=(��−−��)

�� ×��4−��

Setting the dual output

��

= ��−

��−_��−��_��

Example Setting the main output (Vout+ to Vout-)

��

=(18��−2.5��)

(2.5��) ×110��Ω=��Ω

Example Setting the dual output

��

=(5��−2.5��)

2.5�� ×499��Ω−387Ω=��Ω

Example Setting the dual output

��

= 5��12��−30Ω=��Ω

VOUT+ [VDC]

R2 [kΩ]

R1 [kΩ]

110

681

732

768

806

866

909

953

1000

VOUT- [VDC]

R4 [kΩ]

RLIM [Ω]

R3 [kΩ]

499

220

100

301

383

499

715

1300

Note8:

To minimize the power consumption under light loads, it is desirable to choose a resistance value of between 100kΩ and 500kΩ for R4

R24C2T25 Datasheet(PDF) 4 Page - Recom International Power

R24C2T25 Datasheet(HTML) 4 Page - Recom International Power

Html Pages

1 2 3 4 5 6 7 8 9

Datasheet Download

Link URL