1. Features (see Fig. 1 for outside view, and Table 1 for models) of HVHF28 Series High Reliability  DC/DC Converters

Range of input DC voltage: 18~36V, nominal input DC voltage 28V

Output power: 20W

Operating temperature: -55~+125℃

Input, output and case are isolated mutually

Insulation resistance: R≥100MΩ (DC 500V)

With the function of inhibit and short-circuit protection

Power density: 32W/in3

Function of pins: output voltage is adjustable

Totally sealed metal case

2. Scope of application of HVHF28 Series High Reliability  DC/DC Converters

The high-reliability electronic system for aeronautics and astronautics, etc.

Table1 Product models

Single

Dual

HVHF28S5(F)

HVHF28S12(F)

HVHF28S15(F)

HVHF28S8(F)

HVHF28D12(F)

HVHF28D15(F)

3. Description of HVHF28 Series High Reliability  DC/DC Converters

The HVHF28 series products are designed using forward PWM principle and are new generation 20W series dc dc converter  developed through improvement. After being isolated and coupled through optocoupler isolation, the sampling signal of output voltage of the product and the sampling signal of current in input circuit modulate the pulse width of controller at the same time. Its double-output close-loop control makes the product have stable voltage output and short-circuit protection function. Magnetic reset measures effectively prevent magnetic saturation of converter, thus improving the reliability of the product. In addition, the product also has fine adjustment function for output voltage.

These series products are made by the thick-film hybrid integration process and is totally sealed in a metal case. Both the design and manufacture of the product satisfy the requirements of GJB2438A-2002 “General specification for hybrid integrated circuits” and specific specifications of the products. The connection of input into HFG-CE03 power filter can improve EMC performance of the product.