In the last PWM discussion, we devised how is composed the average current, specially when the PWM frequency is faster than it should be, making the period duration comparable with the rise and fall slopes duration of the current. The results were packed up in 2 equations to summarize what is the best choice for … Continue reading Dimming LEDs (part 3/3) – The overlooked boundaries
Dimming LEDs (part 2/3) – Sneaky non-linear events while using the PWM technique
In the previous article we tried to analyze what is the Contrast Ratio in a LED driver and how the non-idealities are giving a boundary on the minimum allowable PWM period. That was quite worth a full article, but a big part was indeed missing. Here we will go through how the PWM period and … Continue reading Dimming LEDs (part 2/3) – Sneaky non-linear events while using the PWM technique
Dimming LEDs (part 1/3) – Analog and digital, not analog vs. digital
While messing around with dimmable DC-DC converters for LED drivers, I had the need to quantify the contrast ratio of a dimmable light. Turns out it is not that trivial, specially when combining switching periods, transients and mixed analog/PWM dimming. Looking for contrast ratio on the internet is only useful if you want to buy a TV, not if you want to build a LED driver. Also, on the web not all information seems to be correct, therefore this article and its possible continuation is the result of long investigations and discussions between engineers.
NTC Measurements (part 2/2)
In the previous NTC Measurements article, was shown the basic approaches and few variations of them in order to use an NTC, by following the suggestions provided in the datasheet and taking the correct assumptions in all the temperature signal processing. These suggestions are usually not provided, because with a bit of math a lot … Continue reading NTC Measurements (part 2/2)
DS1307 RTC Emulator – The Arduino library
Things must come to an end. I decided to make a new library experiment, putting an ending mark to the DS1307 Real Time Clock hacking project, because the project was born as an encapsulation of a real RTC in a PIC microcontroller, wrapping an RTC hardware engine to emulate the DS1307; then a subsequent development on … Continue reading DS1307 RTC Emulator – The Arduino library
HardWire, the enhanced Arduino Wire library
I have spent a lot of time on playing and later working on the I2C buses. I almost always used self developed libraries, both for learning and job requirement purposes. Then, when experimenting with a portability of a project in the Arduino environment, I started to trying the official Wire library, discovering some incompatibilities for my … Continue reading HardWire, the enhanced Arduino Wire library
Lino Project
I am playing with LEDs for few month and during that time some little projects were born, but now I need a system to handle the logical part and the power distribution. I simply just can't use an Arduino board, or any other development board: I need a proper power handling embedded in a small space, … Continue reading Lino Project
Tiny, robust, low cost, fail-safe LED driver: the Glighter-S project
It has been a while since the last LED related article. Was experimented the linear current source, its pros and cons and the field of application. Now arises the need of a small version, handling the same high power, things that are contrapposed in the linear regulator. I need something that I can bring with … Continue reading Tiny, robust, low cost, fail-safe LED driver: the Glighter-S project
Current sources for LEDs – Glighter: a multichannel LED Driver
A power constant current source, high speed, for power LEDs. Taken all the errors made previously, I tried a new linear based current source which should be kept "simple" and "fast".
Current sources for LEDs: firsts DIY impressions
Recently I found that today almost lighbulbs are made with power LEDs. And surprisingly most of them are made so cheap that the controller fails far away before its lifetime. At least for what I've experienced with few models. Most of them seems to work well, and I think that LEDs are the future for … Continue reading Current sources for LEDs: firsts DIY impressions
ALEA 