Hello,
i am working on a simple project for a table lamp i am designing. The lamp will use a Cree XP-G3 led and i am looking for around 250-300lumens. The power supply will be 2xAAA battery giving 2.4v boosted to 5v. The forward voltage of the led at this lumen will be 2.87v and current will be 775mA. The safe wattage will be 2w and i will need to include an inline 3 ohm x 2w resistor.
I have a Pololu booster that will provide the constant output i need but because i have to include a switch and a resistor as well as two jst connectors for the led and battery i am looking at building my own pcb. I have a prototype i have made from perf board using the breakout but am not happy using a breakout attached to a board come pcb. I am hoping therefore to find a circuit using a commonly available IC that i can use to create my own pcb 5v output so i can build a self contained pcb that doesnt use a manufacturers breakout but does provide the current and voltage required from my power source.
Additionally and eventually i will use a 3.7v Lipo battery to replace the 2xAAA and will want to recharge that battery via an external usb 5v power supply so eventually will want to include a lipo charger in the pcb design - although at this stage that is quite a way off.
i am hoping someone here on aac can point me in the direction of suitable schematics that might help me achieve my lofty goals. I have searched and found some that appeared to achieve some of my requirements but given the very small voltages and currents i am working with they appeared to be more than my project required.
Hope someone can help.
i am working on a simple project for a table lamp i am designing. The lamp will use a Cree XP-G3 led and i am looking for around 250-300lumens. The power supply will be 2xAAA battery giving 2.4v boosted to 5v. The forward voltage of the led at this lumen will be 2.87v and current will be 775mA. The safe wattage will be 2w and i will need to include an inline 3 ohm x 2w resistor.
I have a Pololu booster that will provide the constant output i need but because i have to include a switch and a resistor as well as two jst connectors for the led and battery i am looking at building my own pcb. I have a prototype i have made from perf board using the breakout but am not happy using a breakout attached to a board come pcb. I am hoping therefore to find a circuit using a commonly available IC that i can use to create my own pcb 5v output so i can build a self contained pcb that doesnt use a manufacturers breakout but does provide the current and voltage required from my power source.
Additionally and eventually i will use a 3.7v Lipo battery to replace the 2xAAA and will want to recharge that battery via an external usb 5v power supply so eventually will want to include a lipo charger in the pcb design - although at this stage that is quite a way off.
i am hoping someone here on aac can point me in the direction of suitable schematics that might help me achieve my lofty goals. I have searched and found some that appeared to achieve some of my requirements but given the very small voltages and currents i am working with they appeared to be more than my project required.
Hope someone can help.