I am creating a (very small) buck converter for a custom (very bright) flashlight. I need to take the ~7 volt output from 2 LiPOs and drop that down to the point it produces a constant current of 9A across an SST-90 LED (A very powerful 3.6v/9A LED)
The space is limited (this PS has to fit into a cylinder about 10mm tall and 30mm in diameter) AND I need to fit a microcontroller in it as well (I'm using the ATtiny44A) The reason for the uC is to monitor temperature and allow me to program a interface to change the total power to the IC via PWM.
I have found an inductor that fits - 4.7uH at 10A. It takes up about 1/5 of the space. Since space is an issue, I can handle efficiencies of around 80%. I have this thing attached to a fairly large heatsink (the body of the flashlight).
I first thought I can use the ATtiny to handle the switching but soon discovered from reading forums that it can be very difficult to do that. I'm looking for a cheap (and small) IC that can basically take a voltage from a sensor resistor (0.005 ohm) and adjust the duty cycle accordingly. Since I would like to control it via PWM, I will need a way to enable and disable the supply.
Does anyone have any ideas or have advice on what to look for? Any help is greatly appreciated!
The space is limited (this PS has to fit into a cylinder about 10mm tall and 30mm in diameter) AND I need to fit a microcontroller in it as well (I'm using the ATtiny44A) The reason for the uC is to monitor temperature and allow me to program a interface to change the total power to the IC via PWM.
I have found an inductor that fits - 4.7uH at 10A. It takes up about 1/5 of the space. Since space is an issue, I can handle efficiencies of around 80%. I have this thing attached to a fairly large heatsink (the body of the flashlight).
I first thought I can use the ATtiny to handle the switching but soon discovered from reading forums that it can be very difficult to do that. I'm looking for a cheap (and small) IC that can basically take a voltage from a sensor resistor (0.005 ohm) and adjust the duty cycle accordingly. Since I would like to control it via PWM, I will need a way to enable and disable the supply.
Does anyone have any ideas or have advice on what to look for? Any help is greatly appreciated!