| Electronics > Projects, Designs, and Technical Stuff |
| Monolithic Power DC/DC Converter MP2359 |
| (1/2) > >> |
| fossil:
I am newbie and trying to design a dc/dc power supply. Here is a dc/dc converter design for a custom ESP8266 board. The design is based on Monolithic Power Systems MP2359 with 4.5V to 24V input voltage range. The output voltage is 3V3. The reason to choose DC/DC converter instead of an LDO is to provide at least 250mA to any add on board. The minimum input 4.5 voltage for MP2359 is too close to input voltage 5V coming from USB port / mobile charger. The minimum input voltage of MP2359 is well below any droop on input. The attached circuit is based on reference design in datasheet for <5V input voltage. Is there anything else I can do to improve the stability of power supply? Edit: Updated the schematic |
| T3sl4co1l:
What about stability? Like getting desired output (250mA) at lower input (under 4.5V)? Pick a different chip. Tim |
| fossil:
--- Quote from: T3sl4co1l on January 31, 2019, 03:58:07 pm ---What about stability? Like getting desired output (250mA) at lower input (under 4.5V)? Pick a different chip. Tim --- End quote --- I guess the minimum voltage is too close to input. Will select a different chip. |
| mariush:
Just use something else, like for example : AOZ1280 (3.6v min, 26v max, cheap... 60 cents at 25qty, 30 cents at 1k) : https://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AOZ1280CI/785-1277-1-ND/2769845 ^ however be aware that max duty cycle is 87% so you'll need at least 4.2v to get 3.3v stable ... still you should get at least 4.2v from usb, so it should be fine. it's worth knowing if you want to use a lithium (3.7..4.2v battery), you wouldn't get 3.3v quite right. Richtek RT7294C (max 18v in, but 4.3v min, synchronous rectifier so you save on separate diode) : https://www.digikey.com/product-detail/en/richtek-usa-inc/RT7294CGJ6F/1028-1507-1-ND/5724414 RT8299ZQW for 3v..24v in, synchronous : https://www.digikey.com/product-detail/en/richtek-usa-inc/RT8299ZQW/1028-1158-1-ND/3078161 |
| fossil:
--- Quote from: mariush on February 01, 2019, 05:39:42 am ---Just use something else, like for example : AOZ1280 (3.6v min, 26v max, cheap... 60 cents at 25qty, 30 cents at 1k) : https://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AOZ1280CI/785-1277-1-ND/2769845 ^ however be aware that max duty cycle is 87% so you'll need at least 4.2v to get 3.3v stable ... still you should get at least 4.2v from usb, so it should be fine. it's worth knowing if you want to use a lithium (3.7..4.2v battery), you wouldn't get 3.3v quite right. --- End quote --- I had almost decided to use AOZ1280, but later switched to MP2359. I was lazy and wanted to avoid the math needed to design AOZ1280 for 3.3V. MP2359 offered a ready reference design :). I will revisit AOZ1280. --- Quote from: mariush on February 01, 2019, 05:39:42 am ---Richtek RT7294C (max 18v in, but 4.3v min, synchronous rectifier so you save on separate diode) : https://www.digikey.com/product-detail/en/richtek-usa-inc/RT7294CGJ6F/1028-1507-1-ND/5724414 RT8299ZQW for 3v..24v in, synchronous : https://www.digikey.com/product-detail/en/richtek-usa-inc/RT8299ZQW/1028-1158-1-ND/3078161 --- End quote --- I am looking for switching frequency of 1.4MHz or more. Thanks for pointing me to AOZ1280 |
| Navigation |
| Message Index |
| Next page |