For help with the bus itself (not a specific product).
1 post • Page 1 of 1
K38 is the marking for BSS138 which is used to level shift voltage for I2C communications. It also works for higher voltages. The control boards have current sources that operate up to nearly the battery voltage (less BJT saturation voltage). The K38 is then used to level shift that down to a voltage that is safe for the MCU, before going into the current protection resistor. The protection resistor is sized to allow the MCU to pull down or sink a single current source. This means the MCU is well protected while gaining the ability to sink a 20mA current source from a 12V battery and therefore light up a string of LED's or a string of optical coupler inputs like found in solid state relays to turn on three phases with one control loop that still has enough voltage drop for an LED, and can be manually open with a switch.
Who is online
Users browsing this forum: No registered users and 1 guest