Sunday, August 31, 2014


MC34063 is buck boost type of the smps IC . This IC comes in DIP ,SOIC and some other packages and requires minimal circuit for making it work. With just a timing capacitor  and LC external filter.The buck boost is ready to juice up the circuit.
The MC34063A Series is a monolithic control circuit containing the primary functions required for DC−to−DC converters. These devices consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. This series was specifically designed to be incorporated in Step−Down and Step−Up and Voltage−Inverting applications with a minimum number of external components.
Here's the link for the datasheet of the IC. The datasheet includes all the required schematics and values for the IC to operate.

Here's a circuit with external switch with 2n3055 as the external switch as its internal switch can only handle 1.5A of current and limits the current to only 1/2 of 1.5A ie 750mA according to datasheet. 
The following circuit can make it pass about 7 amp output current as 2n3055 output current is 15A. The feed back network will control the output voltage.
This is a online MC34063 calculator.

Here's the 3d of the circuit.

Saturday, August 30, 2014


Here is the circuit for providing the interfacing circuit of RN42 bluetooth module with microcontroller. The DIP switches here is used to configure the device to predefined mode.The data sheet and reference can be found here for RN42.

The PCB for the module is some what like 
The 3D model of the circuit.


Bluetooth are quite popular nowadays. Bluetooth are low powered and are now equipped in every smart phone. Bluetooth is mostly used for wireless audio streaming in music players and headphones and earphones. Bluetooth gives many profiles or services.
One popular service is SPP Serial Port Profile. This serial port profile is mostly used with the microcontrollers and configuring the bluetooth module wirelessly..
Microchip's RN42 device is very low powered about 42uA chip in sleep mode. This gives the serial port profile. Off the box this devices is configured as the 115200 baud rate serial salve device with pairing code of 1234.

  • Fully qualified Bluetooth module
  • FCC Certified
  • Fully configurable UART
  • UART Data rates up to 3Mbps
  • Over air data rate of 721kbps to 2.0Mbps
  • Low power sleep mode
  • Compatible with all Bluetooth products that support SPP
  • Includes support for BCSP, DUN, LAN, GAP SDP, RFCOMM, and L2CAP protocols
  • 3.3V operation
  • Status pin
  • Bluetooth Technology v2.0 compatible
  • Class 2 power output
It will works as a wireless serial pipe.
The RN42 module is quite small in sized 13.4 mm x
25.8 mm x 2 mm.
Here's the interfacing RN42 with devices.

Friday, August 29, 2014


IR4301 is powerful IC with inbuilt power MOSFETS for the class D amplfliers.Many reference designs are available from International Rectifier also using various supplies and also with single supply and also with the dual power supply with both configuration of stereo mode and mono mode. IR4301 is a bit difficult to solder in home with home made PCB but a little effort will make is sound with whole lots of WATTS.

The filter is desingned for about cutoff frequency at around 30KHz and with the ouptut speaker of 4 watts..
With 18-0-18 transformer with 3 amps of current . We can get about 46 volts of output. This circuit can give output to 18*18/4 Watts of power with some lossed in circuit and also in mosfets.

Here's the IR4301 class d amp with single rail power supply .

With some shielded cable as signal source as input and output. This circuit works fine.
Check out the link is you are confused with the terms in class d amplier. 


The barometer designed by freescale is used widely due to its very small miniature size and 8 pin LGA MEMs technology package  with metal casing comes in about size of 3mmx5mm (roughly).
The barometer is available in IIC and SPI protocol and very cheap < 5 dollar in digikey or any other.

This is my first design using the SPI sensor.
The device is now working in 3.3 volt power supply . MIC5225 is SOT23 package 150mA current adjustable LDO regulator.
The final PCB for testing in somewhat like this …

The 3d view is some what like .

The 3d image for the sensor is available in my 3Dcontent central. ..( ).

Thursday, August 28, 2014

Isolated Voltage Monitoring system #1 #5

Isolation is most in some cases. Isolation in electronics requirements  will make the devices safe and also separate the ground. In voltage monitoring systems specially in the battery banks it is important for the signal isoalation.
Isolation can be either galvanic, electromagnetic or optical.
Isolation IC available like of analog devices uses techniques like iCoupler for the isolation.

Isolated Voltage monitoring can be used by isolation the voltage optically like using the linear optocoupler like IL300.

Here is the first circuit for the isolated voltage monitoring.

Wednesday, August 27, 2014


Class D amplifiers have theoretically 100 PERCENT of efficiency. Class D amplifiers are different than other types or class of amplifiers. They are different and we can compare the analogy of class d amplfiers with smps. Class D amplifiers can also be built using the smps controllers like UC3842 or SG3524 smps controllers and PWM generators..
Class D amplifiers first modulated the signal into the PWM and most of them uses sigma delta modulation techniques.
Most of the dedicated class d amplifiers like International Rectifiers' IRS2092 have their dedicated PWM modulator. They also have inbuilt High side And Low Side drivers for Mosfets.
Generally second order LC low pass filter is used for for filtering out the high frequency carrier frequency.
IR4301 is IC >100 watts and have inbuilt mosftest and only outside low pass frequency are required.
Similarly NXP TDA8950 of 340 watts of BTL (Bridge Tied Load)  configuration .

I will be posting circuit using SG3524 and IR4301 and TDA8950.

Sunday, August 24, 2014

Arduino Basic Tutorial (timer interrupt) #3

Atmega328p's got three timers two 8 bit and one 16 bit . This means the timer value can get upto 255 and 65535 for 8 bit and 16 bit timer respectively. We can use this for the generation of the interrupt or many other time related jobs. ..
Here we are using this to toggle the led of arduino.
Since this is basic tutorial we are only using the library file for the timer interrupt which is available at

Thursday, August 21, 2014

Arduino Basic Tutorial SERVO MOTOR #2

This is a simple example of interfacing some extra hardware to the arduino .

Components required
2)Servo motor

Servo motor are popular nowadays and these motor comes with different vareities of sizes and strenghts and function and from different vendors. Servos are dc motors with gears on it and is used for precision control of the position of the motor arm.

These have three pins for power , ground and for signal. 
Servos position is defined by the pulse width of the voltage signal in signal pin. 
But we don't have to worry about the pulse here, arduino servo library will do our work . 

We'll look at the code and interfacing on the next part. 

Wednesday, August 20, 2014

Arduino Basic Tutorial LED Blinking

This is the Basic Introduction and basic tutorial on Arduino. This about how to get started with Arduino ..
For this first tutorial we need
1) Arduino (Any kind of board is OK)
2) PC with Arduino installed.
Here's the Link for The Arduino ""

Generally all arduino is equipped with a LED in pin 13 of it. So we will be using it.