Hot restrike module for HID lamps (17-Nov-2009)

Hot restrike module for HID lamps

The essential feature(s) of the module

By using a single secondary in the transformer a connection pin of the lamp is also functioning as a switch which enables the high voltage generation only when a lamp is present.

This has the advantage that for safety reasons the mechanical construction can be smaller (asymmetric transformer necessary).

A breakdown switch (here indicated as function 13) in series with the ignition circuit is left out.

Detailed description of how to build and use the module

The driver connected to pins 11a/b produces a high voltage resonant voltage. To be able to rectify that voltage the diodes must be a fast type diode, for instance the commercial available BYV26C (available with several suppliers). The diode BYV26C is not only a high speed diode; it has also an extra function build in. This means that the diode can conduct in the wrong way, but without avalanching and thus destroying itself. This has the advantage that the voltage which can be connected on the pins 11a and 11b may vary in a wide range.

Figure left, the circuit with the lamp in place. The "tri -point connection switch" 11b is connected to 12b (lamp) and 11new (primary part ignitor)

Figure right, the situation when there is n o lamp present. The cho ice can be made to use different diameter s for the lamp connection, so pol...