Controller powering
Introduction
The powering circuit provides power to the controller's logic. The KEY input could be internally connected with the battery plus terminal via an internal fuse (if selected). Power to the internal SMPS is controlled by an electronic switch which is commanded through the POWER input.
If flip-flop feature is selected, the powering circuit has a latching functionality, and it is not needed to keep the voltage applied on the power circuit. If flip-flop is not selected, latching is not available and voltage on the POWER pin needs to be kept there for whole period of the controller operation.
The controller is turned ON if the voltage on the POWER pin is higher than 10 V and turned off once the voltage is below 1 V (usually done by connecting the pin to the GND). The flip-flop also enables turning off the controller from the MCU (automatic power off).
The powering circuit has several modifiable solder jumpers (needs to be specified during ordering - not possible to modify it after the manufacturing process) which can modify its functionality (see)
If controller does not turn on and has internal fuse, it is possible that the internal fuse is blown. This can be easily checked by disconnecting the controller from the battery and disconnecting the controller signal wiring. Then, use multimeter to measure resistance between BATT+ terminal and KEY pin. If the value is not near to 0 Ohm, the internal fuse is blown. External 3A slow blow fuse between BATT+ and KEY pin could be used to temporarily fix the problem.
Example connection
Constant ON
Constant on is the simplest powering variant. Controller KEY and POWER pins are connected to the BATT+ terminal via internal fuse. Controller is powered on each time, when voltage is connected to the battery terminals.
Controllers with Activation input can be easily modified to the Constant on just by shorting KEY and POWER pins externally. However, this is not possible for controllers with Flip-flop.
Activation input
With Activation input powering variant is the controller powered on, when voltage on the POWER pin is greater than approx. 10 V (see controller I/O Specification) for details. Controller will remain turned on as long as the voltage on the POWER pin is greater than approx. 10 V. If voltage on the POWER pin is lower than approx. 1 V or pin is left floating, controller is turned off. Connecting voltage between 1 V and 10 V to the power pin is not allowed, since the controller state is undefined and controller could be damaged.
Flip-flop with two buttons
Controller with Flip-flop powering variant is turned on by applying positive pulse (voltage greater than approx. 10 V) to the POWER pin. It is turned on by applying negative pulse (voltage less than 1 V) to the POWER pin. If POWER pin is left floating, controller will stay in the last state.
In the picture below, positive pulse is generated by pressing the ON button and negative pulse is generated by pressing the OFF button. The 22k resistor is used to prevent shortcut, if the both buttons is pressed simultaneously. Alternatively, the on and off pulse could be generated by SPDT switch instead of two buttons.
Controller with Flip-flop powering variant has capability to turn itself off by FW (for example by certain period of time to save energy in the battery).
Flip-flop and precharge
The picture below shows another example of the controller with Flip-flop powering variant. Controller does not have the internal fuse and its control logic needs to be powered externally via the external fuse and ignition switch connected to the KEY pin. This enables the controller to start before the battery is connected to the power stage. After the start-up, controller will precharge the capacitors in the power stage using integrated precharge circuit. If precharge is successfull, line contactor is closed, battery is connected to the powerstage and the controller is ready for the operation.
If needed, start button could be also used. This allows the ignition switch to turn on only vehicle accessory (like DC/DC converter for lights) without turning on the controller. Controller is then turned on by pressing the start button. The ignition switch and the start button could be obtained as one component - key switch with one stable and one momentary position.
Also in this connection, controller has ability to turn itself off by FW (for example by certain period of time to save energy in the battery).
Display and controller with internal fuse
Following schematic shows connection of the siliXcon controller and the siliXcon display. Both, the controller and the display must be in the Flip-flop powering variant. In this connection, controller logic part and the display is powered via controller internal fuse. The whole system is turned on by pressing the button on the display and is powered off by FW (either by long press of the display button or by timeout). It is also possible to use dedicated ON button instead of the display button.
The display connects power GND and communication GND. If display is used together with controller with connected GND and IOGND, do not connect display CANGND to avoid having ground loop.
Display and controller with external fuse
The schematic below shows another connection of the siliXcon display and the siliXcon controller. Both devices must be configured as Flip-flop powering variant. Internal fuse inside the controller is not present. KEY and POWER pins are connected together and via ON/OFF switch and external fuse they are powered directly from the battery. Controller and display turn on, when the ON/OFF switch is turned on, and they are turned off when the ON/OFF switch is turned off. It is also possible to turn off both devices by FW (for example by certain period of time to save energy in the battery).
The display connects power GND and communication GND. If display is used together with controller with connected GND and IOGND, do not connect display CANGND to avoid having ground loop.