Welcome to CUI's Product Spotlight on high power chassis mount dc-dc converters. Learn about product features, applications and protections, as well as CUI's available product line of high power chassis mount dc-dc converters.
The VHK and VFK series from CUI are a line of rugged chassis mount dc-dc converters ranging in output power from 50 watts to 600 watts. Featuring an integrated heat sink for improved thermal performance, the units are able to operate at higher temperatures with a minimal amount of air flow. The series' chassis mount packaging allows users to install the units in applications where a dedicated circuit board for the power system may not be feasible.
In many applications, the system's input voltage can be unstable or vary over a wide range. Often times, the 2:1 input range seen in many industry standard isolated dc-dc converters is not wide enough to address a fluctuating line voltage. The VHK series and VFK400W series offer an ultra-wide 4:1 input range, making them ideal for applications where the dc voltage rail is variable such as battery-fed equipment. As the battery loses its charge, the voltage will drop accordingly. To continue to feed a stable output voltage to the load, the dc-dc converter's input range must be able to accommodate the voltage drop during discharging conditions and voltage rise during recharging conditions.
The output voltages of the VHK and VFK families are preset to nominal values as indicated by the model table in the previous slide. If desired, the output voltage may be trimmed to + or - 10% with an external potentiometer.
| Logic | Positive | Negative |
| SW Closed (VREM < 0.8V) | Output Off | Output On |
| SW Open (VREM > 2.4V) | Output On | Output Off |
The series' output can be enabled or disabled through the REM (on/off) pin. Standard models default to positive logic although negative logic versions are also available from CUI.
The VHK and VFK series provide regulated outputs at the output terminals. When there is a large current and/or the output cable is of some length, the voltage at the end of the output cable may be noticeably lower than at the terminals. The converter can compensate up to 0.5 V of voltage drop through remote sense terminals. To ensure accurate regulation, users should run two separate wires (twisted) from the desired regulation points to the remote sense terminals. Even if the load current is low, users should still connect +Vo to +S and -Vo to -S.
The VHK and VFK series come with built-in over current, short circuit, over voltage, and over temperature protections. In the event of a fault in any of these areas, the converter's output will shut down, recovering automatically when the fault is removed.
The VHK and VFK series' chassis mount packaging allow users to install the units in applications where a dedicated circuit board for the power system is not feasible or is cost prohibitive. Users are able to secure the VHK or VFK series to a chassis and connect the input and output cables via the module's terminal block connectors.
The VHK and VFK series' rugged packaging and high power output make them ideal for a wide range of applications, including transportation, communications and industrial equipment.
Forklift, bus/automotive, marine
Base stations, mesh networks
Oil drilling, construction, automation equipment
CUI's high power chassis mount family is available in 7 separate series from 50 watts up to 600 watts. Output voltages range from 3.3 Vdc up to 48 Vdc.
| Part Number | Power (W) | Input Voltage (Vdc) | Output Voltages (Vdc) | Size (in) |
| VHK50W | 50 | 9~36, 18~75 | 3.3, 5, 12, 15, 24, 28, 48 | 4.25 x 4.0 x 1.5 |
| VHK75W | 75 | 9~36, 18~75 | 3.3, 5, 12, 15, 24, 28, 48 | 4.25 x 4.0 x 1.5 |
| VHK100W | 100 | 9~36, 18~75 | 3.3, 5, 12, 15, 24, 28, 48 | 4.25 x 4.0 x 1.5 |
| VHK150W | 150 | 9~36, 18~75 | 12, 15, 24, 48 | 4.25 x 4.0 x 1.5 |
| VHK200W | 200 | 10~36, 18~75 | 12, 15, 24, 28, 48 | 4.25 x 4.0 x 1.5 |
| VFK400W | 400 | 10~36, 18~75 | 12, 24, 48 | 7.84 x 4.99 x 1.54 |
| VFK600 | 600 | 10~36, 18~75 | 12, 24, 28, 32, 48 | 7.84 x 4.99 x 1.54 |
