by Susan Nordyk @ edn.com
Based on a four-switch single-inductor architecture, the LT3790 synchronous buck-boost DC/DC controller from Linear Technology accommodates an input of 4.7 V to 60 V and delivers up to 250 W of continuous power for use in a variety of automotive and industrial applications. The device operates from input voltages above, below, or equal to the output voltage, making it well-suited for automotive designs where the input voltage can vary dramatically during stop/start, cold crank, and load dump.
LT3790 – 60V Synchronous 4-Switch Buck-Boost Controller – [Link]
Hey, sorry everyone, I know it’s been a while. But I hope this post will make up for that! Anyone who has done embedded programming knows that an easy way for microcontrollers (like arduino) to connect to a PC is through a serial connection. Unfortunately, not many computers have a serial port these days, and while are a lot of chips that will act like a usb-serial converter, they tend to be somewhere in the $3-5 range. However, I found one chip, the CH340G, that only costs 40 cents!
CH340G – alternative USB to serial IC – [Link]
by jmacarthur @ github.com:
The Zeta is a minimal Z80 toggle-switch computer. It has a Zilog Z80 microprocessor, 256 bytes of RAM and the only interface is the front panel which directly sets and reads the address and data buses.
At the moment, there is only one real source file in this repository, an Inkscape-produced SVG which contains the stripboard layout and lasercut paths along with the image for the box top. In the future I’ll try to add a KiCad circuit diagram. This file doesn’t preview well in github because there are some very thin and zero-width lines – turn on outline mode (View -> Display mode -> Outline) in Inkscape to view it.
The Zeta minimal Z80 toggle-switch computer – [Link]
The LTC®3807 is a high performance step-down switching regulator DC/DC controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz.
The 50μA no-load quiescent current extends operating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3807 features a precision 0.8V reference and power good output indicator. A wide 4V to 38V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. The output voltage of the LTC3807 can be programmed between 0.8V to 24V.
LTC3807 – 38V Micropower Synchronous Buck Controller with VOUT to 24V – [Link]
by Michael Dunn @ edn.com:
When we first encountered the offspring of this Digi-Key/Mentor CAD collaboration, it was still in beta, and the pricing model was unclear. Now that it’s here for real, let’s take a quick look.
Mentor meets Digi-Key, low-cost CAD results – [Link]
Kerry Wong writes:
Hysteresis can be added to a comparator circuit to improve its stability, especially when the input signal is noisy. In this post, we will examine the hysteresis characteristics of some common comparator and Op Amps using an oscilloscope.
Perhaps the most intuitive way to visualize the hysteresis in a circuit is to plot the input signal (x axis) against the output signal (y axis). So, if we sweep the input voltage we should be able to see the characteristics of the transitioning of the output voltage due to hysteresis.
Visualizing comparator and Op Amp hysteresis – [Link]
The LTC2983 measures a wide variety of temperature sensors and digitally outputs the result, in °C or °F, with 0.1°C accuracy and 0.001°C resolution. The LTC2983 can measure the temperature of virtually all standard (type B, E, J, K, N, S, R, T) or custom thermocouples, automatically compensate for cold junction temperatures and linearize the results. The device can also measure temperature with standard 2-, 3-, or 4-wire RTDs, thermistors, and diodes. It has 20 reconfigurable analog inputs enabling many sensor connections and configuration options. The LTC2983 includes excitation current sources and fault detection circuitry appropriate for each type of temperature sensor. The LTC2983 allows direct interfacing to ground referenced sensors without the need for level shifters, negative supply voltages, or external amplifiers. All signals are buffered and simultaneously digitized with three high accuracy, 24-bit ΔΣ ADC’s, driven by an internal 10ppm/°C (maximum) reference.
LTC2983 – Multi-Sensor High Accuracy Digital Temperature Measurement System – [Link]
RTC or real-time clock is a kind of computer clock for keeping track of the recent or most current time. Commonly, RTCs are present in almost all or any device, which are electronic in nature that needs to keep time accurate. Meanwhile, temperature sensors are devices that gather data concerning the temperature from a source and convert it to a form that can be understood either by an observer or another device. These sensors can be in various forms and are used for a wide variety of purposes, from simple home use to extremely accurate and precise scientific use. They play a very important role almost everywhere that they are applied; knowing the temperature helps people to pick their clothing before a walk outside just as it helps chemists to understand the data collected from a complex chemical reaction.
The circuit uses a PCA8565 CMOS real time clock and calendar optimized for low power consumption. A programmable clock output, interrupt output and voltage-low detector are also provided. All address and data are transferred serially via a two-line bidirectional I2C-bus with a maximum bus speed of 400kbit/s. The built-in word address register is incremented automatically after each written or read data byte. It also includes a MCP9801 digital temperature sensor capable of reading temperatures from -55°C to +125°C. Temperature data is measured from an integrated temperature sensor and converted to digital word with a user selectable 9 to 12 bit Sigma Delta Analog to Digital Converter. The MCP9801 notifies the host controller when the ambient temperature exceeds a user programmed set point. The ALERT output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupts. Communication with the sensor is accomplished via a two-wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the set point and hysteresis and configuring the device. Address selection inputs allow up to eight MCP9801 sensors to share the same two-wire bus for multizone monitoring. Small physical size, low installed cost and ease of use make the MCP9801 an ideal choice for implementing sophisticated temperature system management schemes in a variety of applications.
The board is basically a carrier for the two IC’s that make up the Real Time Clock (RTC), PCA8565 and the Digital Temperature Sensor, MCP9801. It conveniently combines the two for applications that require RTC and temperature sensing. A particularly useful feature of this RTC is that it can detect power down and record the time at that event. This is ideal for connecting to a microcontroller that does not have an RTC.
I2C Temperature Sensor & Real Time Clock – [Link]
By Eric Mack @ gizmag.com:
There’s another promising contender in the race to supplant the dominance of lithium-ion and metal-hydride based batteries in the world of energy storage. New research from the Karlsruhe Institute of Technology’s (KIT’s) Helmholtz Institute Ulm (HIU) details the development of an electrolyte that can be used in new magnesium-sulfur battery cells that would be more efficient and inexpensive than the dominant types of batteries in use today.
New electrolyte to enable cheaper, less toxic magnesium-sulfur-based batteries – [Link]
This blog post is about my adventures in implementing a stupidly simple way of transferring data over audio to AVR (and why not other embedded chips too), reaching speeds up to 12kbps with really tiny code and memory footprint, using the internal oscillator of Tiny AVR, with hardware parts that cost next to nothing.
12kbps simple audio data transfer for AVR – [Link]