December 2023


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…another watt saved…

A few days ago I posted my driver prototype for a 20 W, 700 mA, 32 V white LED. Under best conditions I reached 85% of power conversion efficiency between the 12 V input and the electrical power delivered to the LED. I was not satisfied and one of my suspicions were substantial losses in the power MOSFET.


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Teaching an old bug new tricks

The 78S40 is not one of the most modern switching regulators, together with its small brother the MC34063 it dates back to the 1990’s. It differs from the 34063 by having an additional, uncommitted operational amplifier inside its 16-pin package. There are many application notes available, since both chips are manufactured by several companies. […]

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LEDs for Christmas

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Knight Rider is back

Now I am completely sold to AVR microcontrollers. ATMEL’s free software seamlessly interfaces to the also free AVR-GCC C compiler and it is really easy to get started with the AVR microcontrollers – both in assembler and in C.

Today I first rewrote yesterday’s assembler code into C in order to get the same […]

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Lights for Energihuset

Today I designed a solar-cell powered LED lighting for a model of the planned energy education centre Energihuset in Uppsala. The model was built by Nyréns Arkitektkontor and equipped with 108 white light-emitting diodes, series connected in groups of three for a common supply voltage of 12 V. The model will be presented at the […]

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