Week 7: (17/3/14 - 21/3/14)

Simulation Problem

This week I started to construct the buck boost circuit in Proteus. I decided to use MOSFET instead of transistor for switching purpose. I also put volt and amp meter for input and output display. However, the circuit only manage to buck from 0.5V to 11.25V as I increase the Rv; the duty cycle D also increase. It cannot boost the output at all. Supposedly, when the duty cycle is more than 0.5, it should boost the output more than the input. Maybe the value for inductor need to be changed. Furthermore, the output is in negative value.

Week 6: (10/3/14 - 14/3/14)

PWM Simulation 

The PWM need to be fix to a constant frequency. I am using IC 555 timer to produce the PWM.  So I try to put a parallel diode at end of each variable resistor leg, and it proved it can be control. From my research, an astable circuit produces a 'square wave', this is a digital waveform with sharp transitions between low (0V) and high (+Vs). I noticed that the duration's of the low and high states may be different. The value for R1, Rv and C1 can be calculated later on.

Week 5: (3/3/14 - 7/3/14)

Problem with The Main Component

I found that it is very hard for to find the LTC 3115-1. The price show in the online market is too expensive and it come with the the whole test board. I have search all the online company, no one want to take for small amount of order.  So, I decided to redesign my buck boost circuit but still using PWM. This time around, I want to go to the basic of buck boost converter. The basic circuit are easy to find those components such as inductor, capacitor and diode. For switch, I can use transistor or MOSFET.

Week 4: (24/2/14 - 28/4/14)

Component Searching

After coming back from Mecca & Medina, I started to find the main component for my project which is IC LTC 3115-1. From my observation, Malaysia's market doesn't have this kind of IC. I have been searching all electronic shop around Jalan Pasar, and no one can offer me the component. So, I decided to buy it online from http://my.element14.com/ .