This article explores design techniques and challenges for implementing an electronic bike (E-Bike) built using a microcontroller or Programmable System on Chip (PSoC). Current E-Bike systems use a microcontroller with external signal conditioning and comparator circuitry to drive the three-phase motor; external ADC and external amplifiers for different sensor inputs; relay driver circuitry for brake … Read more
Here are the final seven articles and the fourth slideshow highlighting articles on the LED Design Center from its inception to the present day.As you know, this design center is fairly new—yet it is packed with really good how-to articles (and more). Personally, I think that good articles are the heart of the Design Centers … Read more
Wave Motion For simplicity, let's consider one of the waves describing either the electric or magnetic field displayed in Figure 3.1. This wave can be considered as a component of the more complex electromagnetic wave. Figure 3.2a shows this wave separately using x and z coordinates. We will now use this to illustrate some of … Read more
The 100-year reign of the incandescent light bulb will endin 2012 as the Energy Independence and Security Act of2007 mandates the phase-out of most incandescent bulbsin favor of more efficacious forms of lighting. New formsof lighting will also need to meet consumers’ expectationsfor light color, dimming performance, lifetime, and the light patternthat a bulb casts. … Read more
Image courtesy of Mario Sanchez, AP No, Beyoncé’s revival of Destiny's Child did not cause the blackout during this year’s Super Bowl game on February 3, 2013. It was combination of technical and communication failures that contributed to the partial power outage according to an independent analysis. Dr. John Palmer of Palmer Engineering & Forensics … Read more
Figure 1 An inductive voltage booster powers the white LED. Assume that at power-up, Q2 is off and Q1 is on. Under these conditions and with Q2’s collector high, Q3 is turned on via Q2’s collector resistor. With Q3 on, current flows through the first half of the inductor (from terminals 1 to 2). At … Read more
LED drivers have lots of featuresand require plenty of externalcomponents. When your applicationrequires no PWM (pulse-width-modulated)dimming or controlled frequencyoperation, your primary concern may bethat too much current could damage ordestroy your LEDs. In this case, you canmake a simple LED-current limiter froma common low-dropout linear regulator.The circuit in Figure 1 is an LED lightbulb for … Read more
Data sheets of LED driver ICs are normally quite impressive. They promise high performance and a wealth of features at a low price. In practice, there are, however, many stumbling blocks that are not mentioned in the data sheet and can cause serious problems for developers. In addition, the development, testing and certification of LED … Read more
To control their brightness, LEDsneed a constant current; this canbe done with a resistor placed in serieswith the LED string. Both the LED-stringvoltage and the supply voltagecan vary, so a dedicated LED driver is amust to guarantee the current accuracy.Two solutions—each with advantagesand disadvantages—are widely used: alinear constant-current LED driveror a step-down switching converter. Linear … Read more
The IEC (International Electrotechnical Commission)Technical committee TC 34 (lamps and related equipment) published the standard IEC 62493 Edition 1 (Assessment of lighting equipment related to human exposure to electromagnetic fields) in December 2009. Its European counterpart, EN 62493, was published by Cenelec in 2010. As the standard deals with safety aspects, it was also published … Read more
