diff --git a/README.md b/README.md index 1b5d387fcecfa912a1a0241deda022175fff81a5..890aa95f9cd477ea2dde539feae6becc44ad93b4 100644 --- a/README.md +++ b/README.md @@ -1,11 +1,10 @@ -Hello! This is my first attempt at a circuit board. It shall hold an H-bridge for motor control, current sensing, and SPI pins for encoder implementation. It is a board that revolves around the DRV8701 (http://www.ti.com/product/DRV8701) gate driver chip. The DRV8701 is capable of driving a varied set of MOSFETS. Chosen here are the AON7410 MOSFETS. -Design Rules: +## Design Rules: -5A continuous/10A peak rating -0-10A to 0-1.5V mapping current sensing -12V Motor @@ -13,7 +12,7 @@ Design Rules: -Not hotter than 70C -DRV8701 Rules: +## DRV8701 Rules: Vgs(voltage applied to MOSFET gate) = 9.5V Ivcp(current capable of being applied to MOSFET gate - dependent on Vm) = 12mA 20v/v conversion for current sense - for 0-10A to 0-1.5V mapping, you need a ~7 mOhm resistor rated for >=2watts @@ -22,13 +21,13 @@ Lots of passive components need to be around the IC. Here is board version 2.0 -TOP +##TOP ![routedTop](media/circuitV2Top.png) -BOTTOM +##BOTTOM ![routedBottom](media/circuitV2Bottom.png) @@ -38,7 +37,7 @@ BOTTOM A few concerns here arise with v2.0 that need to be addressed by checking some parameters in person, which I shall do tomorrow. -Problems +#Problems The fill for GND that goes towards the Motor GND has a choke point at the corner due to the headers for uploading code being right next to the power and GND sources. @@ -54,7 +53,7 @@ shunt resistor. Right now it is set to 7mOhm, which would return to the ADC 150mV/A -Solved Problems/Interesting Challenges +#Solved Problems/Interesting Challenges Due to the way the PWR and GND are conected, I had to get creative with the GND planes. With the limited knowledge I have gathered. I limited the motor GND to the TOP plane, and kept the Bottom ground plane as clear as possible for the Gate Driver @@ -66,7 +65,7 @@ TOP plane, and kept the Bottom ground plane as clear as possible for the Gate Dr -Basic definitions I learned in the process- +##Basic definitions I learned in the process- Bulk Capacitor - Capacitor used to be capable of taking over battery in certain sags. It is set as close to the input as possible. In this case an electrolytic >=10uF. @@ -87,7 +86,7 @@ Net Ties- Just like a trace, except its meant to be isolated from other traces o Kelvin Connection- Way of connecting traces to Rsense. It just makes sense Take it for granted. Google how to do it. It's very simple. -PCB guides: +#PCB guides: 45 degree traces only Kelvin Connection for Rsense @@ -99,7 +98,7 @@ Many many more to be copied from my notebook soon. -Sources: +#Sources: MOSFET: https://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AON7410/785-1581-1-ND/3621507