Wednesday, September 06, 2017

Offline Isolated Flyback LED Controller - LT3799-1

This chip for LED driving has a power factor correction, the critical conduction mode keeps transformer small. A opto-coupler for feedback is avoided by an innovative primary shunt monitor.

Offline Isolated Flyback LED Controller - LT3799-1

The LT3799-1 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part’s internal circuitry and gate driver.

LED Controller - LT3799-1

20 Watt LED Driver using LT799-1

The FAULT pin provides notification of open and short LED conditions. The LT3799-1 offers improved line regulation over the LT3799, but is not designed for use with a TRIAC dimmer.

  • Offline 4W to 100W+ LED Applications
  • High DC VIN LED Applications
  • Gate driver to drive an external high voltage MOSFET.
  • Typical power factors of 0.97.

Tuesday, September 05, 2017

LED Drive using TPS61042

This Chip from TI is simple to integrate into your designs and this solution is good for production of lighting gadgets, here a consistent quality and predictable performance is easily obtained.

TPS61042 30-V, 500-mA Switch Boost Converter  for White LED Applications
LED-driver application that drives four LEDs with 20 mA of forward current and operates from an input voltage range of 1.8 to 6.0 V.

The entire circuit consists of the control IC, two small ceramic caps, an inductor, a diode, and a current sense resistor. The primary power-supply functions and the secondary features such as load disconnect, overvoltage protection, and PWM dimming have been implemented with a control IC and five small surface-mount passive components.

LED Drive using TPS61042

LED-driver considerations - By Michael Day

Many of today’s portable electronics require backlight LED-driver solutions with the following features: direct control of current, high efficiency, PWM dimming, overvoltage protection, load disconnect, small size, and ease of use.

Monday, September 04, 2017

AD636 - True RMS to DC Converter

Working on low signals in the range of 0 mV to 200 mV rms, AD636 makes a precision AC to DC signal conditioner for Instrumentation. DMM, Data Loggers and Process Indicators can use this.

AD636 - True RMS to DC Converter

Using this chip you can make a True RMS Voltmeter for your Lab or Project.

The AD636 is easy to use. The device is factory-trimmed at the wafer level for input and output offset, positive and negative waveform symmetry (dc reversal error), and full-scale accuracy at 200 mV rms. Therefore, no external trims are required to achieve full-rated accuracy.

Some Features and Specs
  • Laser-trimmed to high accuracy
  • 0.5% maximum error (AD636K)
  • Computes rms of ac and dc signals
  • 1 MHz, −3 dB bandwidth: V rms > 100 mV
  • Signal crest factor of 6 for 0.5% error
  • Low power: 800 μA quiescent current

Friday, August 11, 2017


The MOC303XM and MOC304XM devices consist of a AlGaAs infrared emitting diode optically coupled to a monolithic silicon detector performing the function of a zero voltage crossing bilateral triac driver. MOC3041.

They are designed for use with a triac in the interface of logic systems to equipment powered from 115 VAC lines such as teletypewriters, CTRs, solid-state relays, industrial controls, printers, motors, solenoids and consumer appliances, etc

  • Simplifies logic control of 115 VAC power
  • Zero voltage crossing
  • dv/dt of 2000 V/µs typical, 1000 V/µs guaranteed
Motorola used to make these then it was Infineon Technologies now Isocom also makes it

MOC3041 Zero Crossing Triac Output, 6 Pin

See the original Motorola Application below.

MOC3041 Zero Crossing Triac Output, 6 Pin

These were used by me to make solid state relays. Look at the circuits here Power Electronics Circuits. The were used to control Heaters from DC control signal from a Proportional Temperature Controller. The Magnetic Contactors can be avoided for lower powers. At higher powers SCR banks become a bit expensive.

OC3041M: 6-Pin DIP 400V Zero Crossing Triac Driver Output Optocoupler

The SSR has no mechanical wear and tear but heat up at high currents. So if we overrate by 5 Times then it is an excellent solution for lower power controls upto 5 Kilo Watts. The cycle time of Contactors must be 20-60 Seconds to make it last long. In a SSR a one second cycle time is possible as 10-20mS is the switching speed due to zero crossing.

Thursday, August 10, 2017

Precision RMS Value of AC Waveform - LTC1968

"RMS to DC conversion is the truest way to measure the energy contained in an AC waveform."

Linear Technology - RMS-DC Conversion

The accurate measurement of AC for a wide variety of waveforms and noise is difficult. When we make solar systems and inverters, the AC outputs are seldom sinusoidal. The easy method is to use a Precision rectifier/filter, get the average voltage and a RMS calibration/scaling is done for sine is by tweaking a trimpot. This will not show the right values for other waveforms. The other way was, analog computing, with many opamps and a matched pair of transistors; like multipliers and log amps, very cumbersome for manufacturing and testing.

Precision RMS Value of AC Waveform - LTC1968

These single chip solutions like LTC1968 - Precision Wide Bandwidth, RMS-to-DC Converter make it easy to implement an AC Measurement in your embedded, PLC or PC based solution.

LTC1968 - Precision Wide Bandwidth, RMS-to-DC Converter

The LTC1968 is a true RMS-to-DC converter that uses an innovative delta-sigma computational technique. The benefits of the LTC1968 proprietary architecture, when compared to conventional log-antilog RMS-to-DC converters, are higher linearity and accuracy, bandwidth independent of amplitude and improved temperature behavior.

High Linearity: 0.02% Linearity Allows Simple System Calibration

Wide Input Bandwidth:
  • Bandwidth to 1% Additional Gain Error: 500kHz
  • Bandwidth to 0.1% Additional Gain Error: 150kHz
  • 3dB Bandwidth Independent of Input Voltage Amplitude

Friday, August 04, 2017

Texas Instruments - TI Semiconductors

Texas Instruments, better known in the electronics industry (and popularly) as TI, is an American company based in Dallas, Texas, USA, renowned for developing and commercializing semiconductor and computer technology.

Texas Instruments - TI Semiconductors

Chip IC Products include Solutions in Analog, DSP- Digital Signal Processing, Power Management, A/D Converter, Microcontroller based Systems, Mixed Signal Designs, Multiplexers and Thermal Management Solutions.

A Vintage Calculator from TI

Texas Instruments

Texas Instruments - wiki

TI produced the world's first commercial silicon transistor in 1950, and designed and manufactured the first transistor radio in 1954. Jack Kilby invented the integrated circuit in 1958 while working at TI's Central Research Labs.

TI also invented the hand-held calculator in 1967, and introduced the first single-chip microcontroller (MCU) in 1970, which combined all the elements of computing onto one piece of silicon.

Texas Instruments - TI Semiconductors

A Developer Evaluation Embedded System

Texas Instruments Embedded Portfolio Overview is made up of three sub-divisions: Wireless, Microcontrollers, and Processors

Embedded processors are the processing brains of electronics that gather inputs from analog chips and perform computational processing to operate a system.

Wednesday, July 05, 2017

MAX1910 White LED Charge Pumps - Maxim IC

Drives LEDs with a regulated output voltage or current (up to 120mA) from an unregulated input supply (2.7V to 5.3V). These are complete DC-DC converters requiring only four small ceramic capacitors and no inductors. 200mV Current-Sense Threshold Reduces Power Loss.

MAX1910 White LED Charge Pumps - Maxim IC

The MAX1910/MAX1912 are complete charge-pump boost converters requiring only four small ceramic capacitors. They employ a 750kHz fixed-frequency 50% duty-cycle clock.

MAX1910 White LED Charge Pumps - Maxim IC

Figure 4’s circuit improves LED current matching by raising the ballast resistance while maintaining a 200mV VSET. The increased ballast resistance tolerates wider LED mismatch, but reduces efficiency and raises the minimum input voltage required for regulation.

Yet another method of biasing LEDs is shown in Figure 5. In this case, the current through the complete parallel combination of LEDs is set by R5. R1–R4 are only used to compensate for LED variations. This method of biasing is useful for parallel LED arrays that do not allow connection to individual LEDs.

Tuesday, July 04, 2017

MAX1561 - 26V Step-Up Converters - Maxim IC

The MAX1561 and MAX1599 include an internal, high-voltage, low-RDS(ON) N-channel MOSFET switch for high efficiency and maximum battery life. A single DualMode input provides a simple means of brightness adjustment and on/off control.

MAX1561 - 26V Step-Up Converters - Maxim IC

"High-Efficiency, 26V Step-Up Converters for Two to Six White LEDs"

MAX1561 - 26V Step-Up Converters - Maxim IC

Fast 1MHz (500kHz for the MAX1599) current-mode, pulse-width modulated (PWM) operation allows for small input and output capacitors and a small inductor while minimizing ripple on the input supply/battery. Programmable soft-start eliminates inrush current during startup.

Some Features -
  • Accurate Current Regulation for Uniform Illumination
  • High Efficiency Up to 87%
  • 2.6V to 5.5V Input Range
  • 0.3µA Shutdown Current
  • 26V (max) Output with Overvoltage Protection
  • Up to 900mW Output Power with Internal 30V MOSFET Switch
Why Drive White LEDs with Constant Current? - Maxim

Here you can understand how to drive white LED' s for flashlight or Internal lamp. I have tried substituting for tubelights and bulbs. These LED's are amazing. The amount of light at even 100mW is phenomenal. The future is indeed LED Lights. But more Amber component is required in LED to give the warm feeling of an Edison Lamp.

Sunday, July 02, 2017

Cirrus Logic - Analog and Mixed-signal

Cirrus Logic is recognized worldwide for its expertise in developing high-precision analog and mixed-signal integrated circuits (ICs) for a broad range of consumer and industrial markets.

Cirrus Logic - Analog and Mixed-signal

The most respected brands in the audio and industrial markets such as Bose, Harman International, IO, Onkyo, Marantz, Panasonic, Philips, Pioneer, Samsung and Sony rely on Cirrus Logic technology.

Founded in 1984 with headquarters in Austin, Texas, Cirrus Logic is fabless.

CDB5484/80/90 Evaluation Boards

Cirrus Logic - Analog and Mixed-signal

The CDB5484/80/90U boards are designed to evaluate the functionality and performance of the CS5484/80/90 energy measurement IC family. Shunt resistors, current transformers or Rogowski coils can be connected to the analog inputs. Intuitive GUI software provides easy and full access to the on-board CS5484/80/90 device and MCU.

On-board LEDs and LCD displays enable stand alone operation for extended testing. These CDBs enable fast and easy preliminary evaluation of Cirrus Logic's AFE products.

Cirrus Logic, Inc.
800 West 6th Street, Austin, Texas 78701, United States

Thursday, June 08, 2017

IRS2980 - LED Driver Control IC - International Rectifier

A high-voltage buck regulator control IC for LED light bulb replacement, LED tube lighting and other non-isolated LED driver applications.First in a family of high-voltage LEDrivIR ICs, and utilizes hysteretic average current mode control for precise current regulation. EOL

IRS2980 - LED Driver Control IC - International Rectifier

IRS2980 - LED Driver Control IC - International Rectifier

Some of the Features - Dimming LED driver controller, Hysteretic Current Regulation, Closed-loop LED current dimming control, Analog/PWM Dimming Input, Internal High Voltage Regulator.

IRPLLED13 - 90-250VAC Offline LED Driver using LEDrivIR IRS2980

Non-isolated constant current buck regulator,  90-250V AC input voltage, 0-50V DC output voltage, Nominal output current of 350mA.

A simple single st age power converter based around the IRS2980 LED driver IC provides a contro lled current output ov er a wide AC line or DC voltage input range.

The IRPLLED13 evaluation board is an off line non-isolated constant current Buck regulator LED driver designed to supply a nominal 350mA DC output current. The LED output voltage can be up to 90% of the input voltage, operating from an AC line input volt age between 90 and 250VAC 50/60Hz. The IRPLLED13 demo board is not de signed for use with dimmers.

Monday, June 05, 2017

ST7LITE09 and LED driver STP16CP05

A cost effective solution to drive an array of high brightness LEDs, using the LED driver STP16CP05. The Brightness and Color is uniform due to current regulation. High efficiency DC-DC converter. Wide Input voltage range - 5 V to 35 V.



  • DC-DC converter for high efficiency
  • 32 LED matrix driven by STP16CP05
  • LED current regulation
  • Adjustable brightness
  • Animated text capability
  • Adjustable blinking speed
This evaluation board represents a cost effective solution to drive an array of high brightness LEDs, using the LED driver STP16CP05. This driver provides the same constant current for each of its output channels, thus there is no difference in brightness and color between the LEDs.

Friday, June 02, 2017

Constant LED Brightness and LDS8711

The LDS8711 is a fixed frequency current mode boost converter with internal rectifier and cycle-by- cycle switch current limit specifically designed to drive a string of up to 10 White LEDs.

Constant LED Brightness and LDS8711

A Switching Converter Chip with hardly any external components driving a HB LED chain. HB - High Brightness LED. This IC is from IXYS Power Devices.

High efficiency boost converter with the input voltage range from 2.7 to 5.5 V . Drives one LED string with 10 LEDs in series up to 32 mA.
  • 250 mV current sense voltage
  • No external Schottky Required
  • 0.7 MHz Switching Frequency
  • Efficiency greater than 83%
  • PWM LED Brightness Control
  • Low Shutdown Current (<1µA)
LED Current Setting - The maximum current value in the LED string may be factory preset in the range from 10 to 30mAin 0.125mA steps, or set by Smart OneWire interface in the range from 0.125to 32 mA.The average LED string current that determines LED brightness may be controlled applying PWM signal to the EN/PWM pin.

Friday, May 12, 2017

5 Watt LED driver with Zetex - Diodes

The ZXSC400 is a voltage mode boost converter in the SOT26 package. Its low feedback voltage allows the current in a chain of °Cs to be set and accurately monitored with a single resistor giving minimal losses.

ZXSC400 - LED driver boost converter

Shown below is a design from an Application Note of Zetex. Here ZXSC400 drives a Luxeon V Star LED. The input voltage ranges from 4.2V to 5.4 V with a maximum output current of 700mA at 5V input.

5 Watt LED driver with Zetex - Diodes

Voltage mode boost converter in the SOT23-6 package. Its low feedback voltage allows the current in a chain of LEDs to be set and accurately monitored with a single resistor giving minimal losses. Excellent load and line regulation. 1.8V to 8V supply range, regulation of ±1%, 80% efficiency, 4.5µA Quiescent drain.

Zetex range of LED drivers - Diodes Incorporated

LED Drive Solutions and Power Supply Design ideas. Robust and efficient high-brightness LED drivers. Zetex have LED drivers for boost/buck they are cost effective too,

Wednesday, May 10, 2017

SSL2101 SMPS Controller - NXP Semiconductors

The SSL2101 is a Switched Mode Power Supply (SMPS) controller IC that operates in combination with a phase cut dimmer directly from rectified mains. It is designed to drive LED devices..

SSL2101 SMPS Controller - NXP Semiconductors

SSL2101 SMPS Controller - NXP Semiconductors

SSL2101 12W-230V Triac dimmable fly-back demonstration board UM10341

The SSL2101 driver is a solution for a professional application with multiple high power  LEDs that require galvanic isolation and a safe output voltage. It is mains dimmable for  both forward phase (triac) dimmers, and reverse phase (transistor) dimmers.

Triac dimmable fly-back demonstration board UM10341

It can  generate up to 16 W output power, which is equal to a 100 W incandescent lamp (at  63 Lumen/W). Examples are shelf lighting, down lighting and LED lighting for bathrooms  etc. The design demonstrates how to produce a driver that is suitable for small form factor  applications such as retrofit lamps.

Tuesday, May 09, 2017

Solar Cell Voltage Booster with MAX856

This circuit generates an usable power 5V good for charging portables. Even lighting a White LED Array.

A Supercap Flywheel may be good addition to this, these kind of chips can also add supercap power management, as it will take a lot of current to charge up. This will keep power flowing when the sun goes behind the clouds.

Solar Cell Voltage Booster with MAX856

Harnessing Solar Power with Smart Power-Conversion Techniques

"Obtaining all the available energy from a solar panel requires a switch-mode step-up or -down converter and battery charger, in addition to the battery. The converter must ensure that every bit of energy taken from the solar panel is efficiently stored in the battery for future use."

The MAX856-MAX859 are high-efficiency, CMOS, step-up, DC-DC switching regulators for small, low input voltage or battery-powered systems.

Monday, April 03, 2017

Digital Potentiometer - AD5242 - Analog Devices

AD5241 and AD5242 provide a single-/dual-channel, 256-position, digitally controlled variable resistor (VR) device. They have 2-Wire I2C Compatible Digital Interface.

Digital Potentiometer - AD5242 - Analog Devices

They are Analog Semiconductor Replacements for Electromechanical Devices like potentiometer, trimmer or variable resistor.

The Advantage of the latter is low cost and easy to configure and use. The Advantage of the Digital Version is "No moving Parts". hence not limited to things like "10000 operations". Another clear advantage is precision and vibration resistant.

See an Application of this Digipot in a TinyOS hardware magnetometer.. 

Digital Potentiometer AD5242 Magnetometer Application

The temperature stability of 30 ppm/°C and low noise settings is also achieved with SiCr thin film resistor technology. They range from 10K, 100K and 1M Ω End-to-End Terminal Resistances.

Digipots are not for high currents or power, even high voltage and very low resistance values are not for these devices. These are signal control devices. Use it for analog circuits and instrumentation and signal control too.

MAX5160 Digital Potentiometers - Maxim

They are linear-taper digital potentiometers perform the same function as a mechanical potentiometer or a variable resistor.

MAX5160 Digital Potentiometers - Maxim

Three resistance values are available for each part type: 50kΩ,100kΩ, and 200kΩ. A nominal resistor temperature coefficient of 50ppm/°C end-to-end and only 5ppm/°C ratiometric.

MAX5160 Digital Potentiometers - Maxim

This has 32 Tap Positions, 400Ω Wiper Resistance, 3-Wire Serial Data Input . Power-On Reset: Wiper Goes to Midscale (position 16).

See an application circuit of this chip - A solid-state industrial potentiometer simulates an equivalent mechanical potentiometer, and fits in the same space. 

Industrial 0V to +10V Digital Potentiometer

The key to this circuit is a low-power digital potentiometer IC, 100kΩ version (U3). Configured as a voltage divider, this IC provides an output of 32 discrete voltage steps between its minimum and maximum settings (0V and 5V). A low-power linear regulator (U1) provides a +5V supply rail for U2, U3, and a resistor ladder internal to U3 (whose maximum rating is +5V).

Saturday, April 01, 2017

AD8436 - Low Cost RMS to DC Convertor

This chip from Analog Devices  computes a precise dc equivalent of the rms value ac waveforms, including complex patterns such as those generated by switchmode power supplies and triacs.

AD8436 - Low Cost RMS to DC Convertor

There is an evaluation board available to study its performance.

AD8436 - Low Cost RMS to DC Convertor

Delivers true RMS or average rectified value of an AC input and Fast is settling at all input levels.It is an Accurate conversion with crest factors up to 10.

AD8436 - Low Cost RMS to DC Convertor

Typical application for frequencies as low as power line, and above. The recommended averaging, crest factor and LPF capacitor values are 10 μF, 0.1 μF and 3.3 μF.

Other Features
  • Accuracy: ±10 µV ± 0.5% of reading 
  • 100 µV rms to 3 V rms (8.5 V p-p) full-scale input
  • 1 MHz for -3 dB (300 mV) 
  • 65 kHz for additional 1% error 
  • Zero converter dc output offset 
  • Low power: 300 µA typical at ±2.4 V

Sunday, March 05, 2017

TPS65070 Handheld Gadget Power Chip

One chip that takes care of all Power requirements in a Portable Electronic Gadget. Power Management Multi-Channel IC (PMIC) Solutions - PMIC Solutions with and without Battery Charger.

TPS65070 Handheld Gadget Power Chip

A battery charger for single Li-Ion or Li-Polymer cell. The voltages needed for an embedded system. Includes PWM mode using I2C. wLED Boost Converter, Touch Screen Interface. 10 Bit A/D Converter too.

TPS65070 Handheld Gadget Power Chip

Charger/Power Path Management:
  • 2A Output Current on the Power Path
  • Linear Charger; 1.5A Maximum Charge
  • I Limit - 100mA/500mA/ 800mA/1300mA
  • Thermal Regulation, Safety Timers
  • Temperature Sense Input
Battery charging, gauging and protection

"As different battery technologies like Lithium Iron Phosphate (LiFePO4) and Super Capacitor are becoming more popular, TI .........."

Figure below shows a complete application diagram that details how to connect the TPS65070 to power an OMAP-L132/L138 application processor.

TEAC USB Interface

The TPS65070 is a single-chip with multiple voltage outputs. Here it provides the different voltages required by the DSP chip. It is a convenient, integrated solution to provide the power to the main chip instead of using separate regulators.

Saturday, March 04, 2017

LT1510 - CC CV Battery Charger

A Circuit for charging NiCd, NiMH and Lithium-Ion Batteries.PWM 500kHz with Soft Start and Shutdown Control.

Linear Technology - LT1510 - CV CC Battery Charger

The LT1510 can charge batteries ranging from 2V to 20V. Ground sensing of current is not required and the battery’s negative terminal can be tied directly to ground. A saturating switch running at 200kHz (500kHz for LT1510-5) giveshigh charging efficiency and small inductor size

LT1510 - CC CV Battery Charger

Notes -

Some things to know in battery charging. A battery that has drained will almost appear like a short circuit to the charger. A battery is never fully drained, if you want a nice battery life. Overcharging a battery can damage it and is not safe too. We have to charge it with an optimum current, upto a Top up charge voltage only. Then a trickle to compensate for internal leakage on no-load. Float charging and Cyclic charging are some popular methods.

It can charge lithium-ion (Li-Ion), nickel-metal-hydride (NiMH) and nickel-cadmium (NiCd). These require constant-current and constant-voltage charging. A 2A peak current switch for Boost Charging may be helpful for charging Lead Acid Batteries too. A 0.1 ohm current sense shunt makes charging current programmable.

3.6v and 3.7v Lithium Battery Charger

The charger is based on the LT1510IN Constant-Voltage/ Constant-Current battery charger IC from Linear Technology. It can be configured to charge NiCd, NiMH or Lithium-Ion (and Lithium-Polymer) batteries at up to 1.5 Amps.

Thursday, March 02, 2017

Fast-Charge Controllers - MAX712 and MAX713

Uses MAX712/MAX713 fast charge controllers. PCB Design too. The only difference between them is the battery-fully-charged sensing method. The MAX713 is designed for NiCd batteries, while the 712 is for NiMh batteries.

Fast, smart and universal NiCd/NiMh battery charger

This is a project by Roberto Barrios at his Ham Projects EB4EQA Site.

Application Note - The MAX712 terminates fast charge by detecting zero voltage slope, while the MAX713 uses a negative voltage-slope detection scheme.

Fast-Charge Controllers - MAX712

The MAX712/MAX713 are powered by the DC source via an on-board +5V shunt regulator. They draw a maximum of 5µA from the battery when not charging.

Fast-Charge Controllers - MAX712 and MAX713

Some Specs
  • Charge 1 to 16 Series Cells
  • Supply Battery's Load While Charging (Linear Mode)
  • Fast Charge from C/4 to 4C Rate
  • C/16 Trickle-Charge Rate
  • Automatically Switch from Fast to Trickle Charge