The nucon DCDC converter principle:

The nucon DCDC converter principle combines the function of different converter principles with relatively little components required. In the following drafts the normally used converter principles are shortly described first:

The flyback converter charges up an iron core or reaspectively the magnetic field inside a transformer. When switching off the transistor the temporarilly stored magnetic energy is discharged over the diode into the charge capacitor CCharge. There is no continuous energy transformation.

LED Step down principle including patent applied temperature protection

The buck regulator is like the flyback storing energy inside an inductor. Because there is no transformer with two wirings there can be always an non interrupted current flow over the choke. It can be operated in two modes the interrupted (like flyback) and the continious mode. The example shows that a micro controller can be applied to drive an LED buck directly with all features required: The controller tests if an LED is connected, shuts down if not or if a short is detected, calculates current and the temperature of the LED.

The micro controller can replace special ICs if the software is done right, which is our special know-how. The micro controller is in the design phase an embedded measurement instrument. Information can be send by serial interface for that purpose or later it is easy to make a wire less application with it.

The forward converter transfers energy directly over the transformer when the transistor is switched on. When switching it off the remaining magnetic field of the transformer is discharged over an extra wiring w3. On the secundary side the pulsed current into the charging capacitor CCharge is smoothed by a choke which needs another free wheeling diode.

The push pull converter transfers energy directly by mutual conductive transistors switch1 and switch2 over the transformer. An addtitional wiring is not needed to discharge the magnetic field of the transformer, because the magnetic field of the transformer is used in both directions. Due to the PWM regulation the transferred current flux is still not continuous.

The push pull principle is realized in different ways. Different from case to case this takes a lot of effort to control and a huge amount of components. The picture shows an example with 4 wirings, 2 diodes and 2 transistors. It's also possible to apply the transformer with only two wirings having 4 transistors on the primary side und 4 diodes on the secundary in a full bridge arrangement also. A lot of effort is needed to drive the iron of the transformer symmetrically. But using the full magnetic stroke of the iron leads to a higher energy flux through the transformer.

NUCON DCDC converter principle:

The Nucon DCDC converter principle operates with only one transistor on the primary side as a forward as well as a blocking converter, where Cboost in combination with the wiring w3 allow symmetrical usage of the transformer iron. Cboost causes very fast changes of the magnetic flux inside the transformer, so that high output voltages can be achieved. With the full bridge rectifier there is a continuous energy flux through the transformer. Depending on the PWM ratio the ratio of forward mode energy transfer to blocking mode energy transfer is changing, because there is no interrupt in between two modes of operation and a continuous output, while using the full magnetic stroke, higher harmonic interferences can be kept low and high efficiences can be achieved. The converter is ideal to generate high voltage out of low voltage, especially to the repetitive charging of a capacitor (i.e. in photo flash lights). The principle works as if a variable transformation ratio of the transformer would adjust itself to the secondary load condition. As a meaning for limiting peak inrush currents through main power switch the C buffer cap is a smaller ceramic capacitance which is capable of delivering big current bytes while being emptied without bearing losses because of it's very small ESR. The other current limiter is the secondary inductor L2. This inductor can be selected also quite small it is just ment to break down an initial peak current. Actualy the digital software PWM control of the converter is the key of technology to prevent over currents and to keep the components within their maximum limits. Even their is today the patent rights timed out, the know-how is protected by software.

In our current designs the hardware is further improved and we use on the secondary side just two diodes !