This booster is designed to power stationary DCC decoders that are often used to control switch machines, signals and other off-track accessories.
The Accessory Booster uses the an SN754410 Quad - Half H-bridge IC. The continous output current rating for this circuit is 1.0 amp. The booster can operate from 12 to 18 volts DC.
The DCC input signal for the booster can be taken directly from the output of another booster or the 5 volt output signal from a DCC controller.
The main reason to use a separate booster for stationary decoders is so that a short circuit that trips the track power booster does not also shut down non track systems which may affect the programming of some stationary decoders.
Also, a separate booster for accessories will free up power from the track booster for locomotives.
The SN754410 driver IC has 4 - Half H-Bridge sections. The sections are used in pairs to form a Full H-Bridge.
The SN754410 was not designed to have the output sections connected in parallel, therefore the maximum current capacity of the device is lees than 2 amps even with a heatsink. However, the SN754410 is relatively inexpensive and does not need any external components.
The following diagram shows the schematic for the circuitboard for the 1 Amp - DCC Accessory Booster.
This circuit is designed to make use of surplus - 15 volt, 3 amp laptop power supplies. One supply can power several Accessory Boosters.
Used laptop power supplies can be can be purchased inexpensively at many computer and electronics recycling facilities. (Have them tested before purchasing.) These supplies are also available through many other sources as well.
The DCC Booster circuit will be damaged if the polarity of the power supply is reversed. Care must be taken when connecting a power supply to the circuit board.
This booster is designed to make use of surplus, 2 and 3 amp - 15 volt, laptop computer power supplies that can be found for low cost at many computer repair or disposal centres.
However, any power supply with an output between 12 to 18 volts DC at 2 amps can be used with this booster.
Power supplies with isolated outputs should be used with this circuit. Isolated means that the output of the supply is not electrically connected to the ground and/or neutral wires of the high voltage, AC supply circuit.
If a power supply has a grounded, 3 prong plug, it might not be suitable for use with DCC boosters as the negative terminal will likely be directly connected to the ground pin of the AC power plug.
If a track booster's DC power supply has sufficient capacity, it could be used to supply this accessory booster.
Power supplies for this booster do not need to be regulated but they should be well filtered.
A 1 amp fuse should be used to protect the booster. Branch output circuits could have their own, lower current, fuses.
The SN754410 driver IC has built-in thermal protection but this cannot be relied on to protect the booster or its power supply.
The accessory booster can be used to drive small motors for animation but should not be used to supply power to the track and locomotives.
The circuitboard for the DCC Accessory Booster is 2.9 inches long by 1.9 inches wide. The board is commercially made but has not been tinned or silkscreened.
1 - DCC Booster circuit board only is 11.50 dollars US, plus postage.
(Aditional circuit boards are 11.00 dollars each.)
1 - DCC Booster circuitboard and a kit with all parts is 22.00 dollars US each, plus postage.
1 - Assembled - DCC Booster circuitboard is 22.00 dollars US each, plus postage.
If you are interested in a printed circuitboard, please send an email to this address: firstname.lastname@example.org
Your message will be answered as soon as possible.
PARTS LIST GOES HERE
The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.
If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.
Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.
18 March, 2011