Wireless Power Transmitter Analog Front End

Nowadays, wireless power charging has become more and more common among mobile devices. Due to its widespread use, Wireless Power Consortium (WPC) created the Qi standard. This Qi interface standard is created for inductive electrical power transfer over distances of up to 4cm. The Qi system is used by placing the mobile device on top of the power transmission pad. It charges the mobile device via resonant inductive coupling. This project is a design of a wireless power transmitter analog front end. It contains all of the analog components required to implement a WPC compliant 5-V transmitter. Read more

ADA4530 Electrometer-Grade Amplifier

This design is used to evaluate the ADA4530 femtoampere (10^-15 A) level input bias current operational amplifier, suitable to be use as an electrometer. It has an operating voltage range of 4.5V to 16V enabling it to operate in conventional 5V and 10V single supply systems as well as ±2.5V and ±5V dual supply systems. The board also offers low offset voltage, low offset drift, and low voltage and current noise needed for the types of applications that require such low leakages. To maximize the dynamic range of the system, it has a rail-to-rail output stage that can typically drive to within 30mV of the supply rails under a 10kΩ load. Read more

Low-Cost Flexible Voltage Supervisor and Battery Tester

Batteries are common power source for any electronic components. Preventing it from draining too much below its nominal voltage will help to prolong its lifespan. This reference design is low-cost voltage supervisor and battery tester. It implements the monitoring of multiple, user defined voltage rails while reducing the overall system cost. The main component TLV61225 is a single-cell high-efficient step-up converter that provides power supply solution to products that being powered by a dry cell or up to two Alkaline, NiCd, or NiMH cells with a typical terminal voltage from 0.7 V to 3.3 V and can output 3.3-V voltage. The ATL431 is three-terminal adjustable shunt regulator that provides a 2.5 V output for the resistor ladder. The reference design also incorporates the TPD1E10B06 and TPS27081A, which are single channel ESD transient voltage suppression diode and a high-side load switch used also for ESD protection, respectively. The board also had the LM339, a quad differential comparator that is designed for single power supply.Read more

40W Class-D Audio Amplifier with Digital Master Volume Control

The OPA1688 device used in this design belongs to the SoundPlus family of Texas Instruments. It is a low-noise operational amplifier designed for audio applications. It can either operate using a single voltage supply or a split voltage supply. The MAX5486, which is also used in this project, is a dual 40kΩ digital logarithmic potentiometer that has a debounced pushbutton interface ideal to control the volume and balance the left and right channel of this project. It has 32 log-spaced tap points with a buffered wiper. The power amplifier in this design is the TPA3106D1, which is a 40W class-D audio power amplifier with 92% efficiency that eliminates the need for an external heat sink. Read more

6W Inductor Free Stereo BTL Class D Audio Amplifier Circuit Diagram

The circuit is a class-D 6W inductor free audio amplifier for BTL (bridged-Tied Load) stereo speaker at up to 6Ω to 8Ω per channel. The TPA3144D2 has an advance EMI suppression technology with spread spectrum control and 1SPW modulation scheme that enables the use of inexpensive ferrite bead filters at the outputs. The design is applicable in inductor free application with limited distance length of wire between the amplifier and speakers. Read more

High Amperage Power Supply Plugs

The electronic devices become more compact. This is due to the creation of external power supply allowing the devices to require smaller space for its main board. The design is a high amperage power supply that can produce up to 10A current output. It is able to provide more than industry-standard power capability. The removal of cooling system and some internal power apparatus is approved by UL standards. Read more

TMP107 Digital Temperature Sensor

Traditionally, thermistors are used as temperature-sensing element in some applications. Nowadays, digital temperature sensors are widely used and eventually have replaced thermistors due to its high accuracy. This reference design uses TMP107 digital output temperature sensor that supports a total of 32 daisy-chained devices. Each sensor has a unique 5-bit address stored in electrically erasable programmable memory (EEPROM). The TMP107 is capable of reading temperatures with a resolution of 0.015625°C, and is accurate to within ±0.4°C in the range from –20°C to +70°C. Read more