Monday, October 18, 2010

1.5V to 5V DC-DC Convertor

I was looking for a simple solution for pumping 1.5 volts to 5 Volts. I have designed various 1.5v- 5V DC-DC Convertors by using special purpose chips. The problem was those chips are very difficult to obtain. Moreover, DC-DC Convertors are mostly required to use coil which is also difficult to get.

Luckily, I found this small breakout board in a local electronics shop (NPE). It was cheap, about USD 10 and small enough to fit in watch case (in the future).
The instruction is very simple, put 1.5 Volt in your will get 5V at the output.

By using this breakout board with my USB battery charger
Attaching this module to my digital wristwatch, then I have a working digital wristwatch. It can be charged via USB. Fully charged batter will make the watch lasts for 10-12 Hours (the display is always on). Now, it needs good case + strap. I have idea but don't have time to continue the project.
I have a plan to disclose the making process and give away the PCBs. But, there are some mistakes in the PCB. The problems can be resolved via firmware. However, I think it's not good to give away the incorrect PCBs. Please wait for the good PCBs and I'll give away some.

Free Circuit Simulator Software

My list of Free Circuit Simulator Software
  • Multisim Free Version
  • Many types of simulators from Linear Technology
    • LTspice IV (Switchercad) is free and powerful. It features all IC chips from Linear Technology. SwitcherCAD™ III is a fully functional Spice III simulator with enhancements and models for easing the simulation of switching regulators. This Spice is a high performance circuit simulator, integrated waveform viewer, which also includes schematic capture. Our enhancements to Spice have made simulating switching regulators extremely fast compared to normal Spice simulators. Included in this download are Spice, Macro Models for 80% of Linear Technology's switching regulators and over 200 op amp models. Furthermore, resistors, transistors and MOSFET models are included as part of this package. With this Spice simulation, viewing of the waveforms of most switching regulators can be achieved in a few minutes on a high performance PC. Also, full circuits using op amps or transistors can easily be simulated.
  • Intusoft ICAP4 Demos : A lot of limitations