Freescale Freedom Boards are a series of ultra-low-cost development platforms featuring the Kinetis family of MCUs based on the ARM Cortex M Series Cores. The boards are compact In a size a little bit bigger than a credit card. It can provide easy access to the MCU I/O pins, low-power operation and an open standard embedded serial and debug adapter (Open SDA). Other added features include two USB Mini-B type connectors where one is labeled K20 that acts as a USB host and the other is labeled SDA for a built-in debug interface for flash programming and run-control.
In the video is the K20D50M Evaluation Board that comprises a K20 Processor based on the ARM Cortex-M4 processor. Some other features of the board include an accelerometer, ambient light sensor, RGB LED and a capacitive touch slider. K20D50M I/O pins are also routed out in such a way that it is compatible with Arduino Shields, a third-party expansion board. This also means that K20D50M can be supported by a range of Freescale and third-party development software. Read the rest of this entry »
Modern DC/DC controllers from company Infineon, like TLF51801ELV manage even big challenges.
Perhaps everyone knows, that modern switch-mode power supplies are able to efficiently convert voltage and to replace linear power supplies. Features of ready-made DC/DC modules as well as SMPS controllers themselves are still better and nowadays it´s no problem to construct a 10A power supply on a small area. It is necessary to say, that for the most of applications it´s more advisable to use a ready-made module with proven features, developed by specialists in a given segments, like for example modules from company Traco. Despite this, there are surely many applications, where from several reasons it´s beneficial to use an own design. Offer of controllers for switch-mode power supplies is wide and this time we´d like to introduce you a modern step-down (buck) controller TLF51801ELV from company Infineon.
TLF51801 is interesting mainly by its overall „robustness“, because it´s directly designed for a construction of power supplies with a high output current (up to approx. 10A), what is also reflected in the MosFET drivers sizing, integrated soft start, under- and over-voltage protection, temperature protection, possibility of current limit setting and another features. Very beneficial is also a duty cycle of up to 99% enabling operation with a minimum difference (dropout) between input and output voltage.
TLF51801 is designed as a controller with a voltage feedback requiring 2 external N-FET transistors sized for a desired output current. Current monitoring (via pins SenseLow+SenseHigh) can be done through external sensing (shunt) resistor or with an advantage of a higher overall efficiency even an internal resistance of an FET transistor (RDSon). TLF5180 can operate in a wide range of input voltages 4,75-45V and at frequencies of 100-700kHz, while the clock frequency can be synchronized to an external clock. The circuit can be easily switched off via the “En” pin (enable), when it consumes only 2uA. An integrated thermal protection switches off the circuit at exceeding 175°C and switches on again (+SoftStart) after cooling down to 160°C.
The circuit TLF51801ELV is a brand new type and it will be soon available upon order. Detailed information will provide you the TLF51801ELV datasheet.
10A with 96% efficiency … no problem for TLF51801 - [Link]
Dave assembles his first uCurrent in the SMD reflow oven. With random running commentary while pick and place assembling.
EEVblog #562 – More SMD Oven Reflow - [Link]
by Thomas Mosteller:
Despite the long-predicted demise of the 4- to 20-mA current loop, this analog interface is still the most common method of connecting current-loop sources to a sensing circuit. This interface requires the conversion of a voltage signal—typically, 1 to 5V—to a 4- to 20-mA output. Stringent accuracy requirements dictate the use of either expensive precision resistors or a trimming potentiometer to calibrate out the initial error of less precise devices to meet the design goals.
Convert 1-5V signal to 4-20mA output - [Link]
Invensense MPU6050 is an integrated gyroscope and accelerometer with 16-bit readings. It contains 2 dies, soldered face-to-face in multiple places (that’s what was causing us troubles last time!).
On the overview photo you can see how not-flat they are. On a bigger die MEMS part is 28µm above surface, on smaller die – 100 µm above. Also, there is logic right under MEMS on the bigger die.
Invensense MPU6050 6-axis MEMS IMU die-shot - [Link]
by Aruna Rubasinghe:
The LM317T from National Semiconductor is a popular adjustable-voltage regulator that provides output voltages of 1.25 to 37V with maximum 1.5A current. You can adjust the output voltage with a potentiometer. The circuit in Figure 1 replaces the potentiometer with an analog voltage that you can control from a PWM (pulse-width-modulation) signal. You control this signal with a microcontroller or any other digital circuit. You can use the same microcontroller to dynamically monitor the output and adjust the LM317T.
Control an LM317T with a PWM signal - [Link]
DigiPot is a digital potentiometer using a rotary encoder as input along with a 7 segment display that show the current pot value.
The “potentiometer” is actually a rotary encoder (TW-700198) connected to a microcontroller that reads the signal from it and convert it to a value that is displayed on 7-segment displays. The value also is sent via i2c/spi/serial/usb to the host. Also 3 LED and included for status indication.
DigiPot – Rotary Encoder Potentiometer - [Link]
The PicoBuck is a small and inexpensive 3-channel LED driver. It employs constant-current buck driving which approaches an efficiency of 95% (theoretical). It’s based on AL8805 LED Lighting Buck Driver from Diodes Inc.
PicoBuck – RGB LED Driver - [Link]
This project is an accelerometer data acquisition system for automotive suspension analysis. In other words it’s a low frequency spectrum analyzer based on Lanchpad TIVA Series from Texas Semiconductors. It’ s a spectrum analyzer for mechanical frequencies (max. 50 Hz). In my application I use this analyzer for the signals from a suspension of a car, that contain information about comfort (ride) of a vehicle.
Low Frequency Spectrum Analyzer for Automotive Suspension Analysis - [Link]
This project is car hands free that retransmits the audio signal from a cell phone to the FM broadcast band. By placing the cell phone’s speaker near the microphone, the user can use the phone as a hands-free device while driving.
MAX2606 – Hands-Free Car Kit for Cell Phones - [Link]