The goal of this project is to demonstrate the design, simulation, and construction of an in-car cellphone charger. The entire process will be recorded on video for educational purposes.
Specifications
Input: Car Battery 12V nominal (11.4V-12.9V)
Output: 5V, ~0.5A cell phone charger
Design Parameters
Vin: 12V +/- 2V
Vout: 5V
Iout: up to 1A; +/- 50mA ripple
f_sw: 500kHz
Component Selection
IC: TPS5410: 1-A Wide Input Range Step-Down Swift Converter from TI
I have listed some possible components to use in the charger.
Another option might be a QFN socket. This is one possible company.
Input: Car Battery 12V nominal (11.4V-12.9V)
Output: 5V, ~0.5A cell phone charger
Design Parameters
Vin: 12V +/- 2V
Vout: 5V
Iout: up to 1A; +/- 50mA ripple
f_sw: 500kHz
Component Selection
IC: TPS5410: 1-A Wide Input Range Step-Down Swift Converter from TI
I have listed some possible components to use in the charger.
- A simple TI controller with integrated switch. The only problem is it has a 1 Amp current limit and we want 0.7 Amp limit. It also has a max switching frequency of 52 kHz.
- Another TI controller with integrated switch. This one allows use to set a peak current limit I think. Its max switching frequency is 100 kHz.
- Another TI controller with integrated switches. This chip has integrated synchronous switches and allows switching up to 1 MHz. I think something like this one will be the best. It comes in a tiny QFN package so we may want to find something a little bit bigger.
- After much searching, this part seems to be the best one: TI TPS62112 I've order 4 free samples from TI. The main problem is that the QFN packaging might be smaller that we want. I think we might just have to learn to live with it though. I couldn't find a suitable replacement that was any larger.
Another option might be a QFN socket. This is one possible company.