LED power rev 3
jkominek opened this issue · comments
- Need a bit more thermal relief on the passives connected to the top layer copper pour. They're sort of a pain to hand solder.
- C10 (incoming .1uF on the 48V rail) is just a bit too close to J9
- Why did I use different resistor values for R24 (Vref drain) and R9 (/SHDN pullup)? No reason I couldn't just use some arbitrary value in the 2.2k-5k range for both. Pick something I'm using elsewhere (the dividers?) that actually matters and just use that for both, to reduce BOM.
- R0 is unnecessary for draining the big cap now that we've got the voltage divider on +48V, draining 0.5W all the time (huh, maybe i should up the total resistance of the voltage divider)
- Eliminate the need for the +15V supply, by regulating the +48V down to about +24V with an LM317. Should be cheaper than putting the second screw terminal on the board. The op amps can use the +24V directly, and that should be low enough for the 5V regulator feeding the precision voltage reference. Expected current draw on the whole rail is <1mA, as we're just feeding quiescent currents and the op amps are keeping MOSFET gates stable.
- /IRQ line should be pulled down with a transistor, instead of directly attached to a pin.
All of the changes were made in ef2d1cc.
No need to worry about the MCP23017; replaced it with an STM32G0 that has ADC inputs.
Will leave this issue open for the time being, in case I think of anything else I want to change.
Switched to a BJT to pull down the interrupt line in 5b2fe51.
dc4713c marked as rev 3 and ordered