8
CY3280-MBR CapSense Express with SmartSense Auto-Tuning Kit Guide, Doc. # 001-64772 Rev. **
Kit Operation
2.1
Power Supply
CY3280-MBR kit can be powered from two different power sources: external power supply and on-
board battery power. External power supply can be provided from two connectors: J5 and J2.
External power supplied through J2 is gated by the CapSense based power button; however, exter-
nal power supplied through J5 is not gated.
■
On-board battery power supply (place AAA batteries in the battery holder)
■
External supply (use pin #41 and pin #39 of Header J2 to connect VDD and GND, respectively)
■
External supply (use pin #1 and pin #2 of Header J5 to connect VDD and GND, respectively)
While the external power option supports all operating power supply from 1.71 V to 3.6 V, the on-
board battery power supply provides only 3 V operation.
For the kit to work, at least one source of power should be active. The CY8CMBR2044 CapSense
controller is powered 200 mV less than what is supplied to the power supply connector J2 due to
voltage drop across regulator circuitry. External supply to be used should be greater than 2.0 V and
lesser than 3.8 V to provide 1.71 V to 3.6 V supply to the CapSense controller.
2.2
System Block Diagram and Operation
shows the block diagram of the CY3280-MBR kit. The block diagram has two main
sections, power supply and CapSense controller sections. The power supply section is based on the
external and on-board battery power. Power on and off control is implemented using a CapSense
based power button, which is activated every time the kit is powered. Demo CapSense controller is
powered only if the CapSense power buttons is touched to turn on the kit.
Figure 2-2. Block Diagram of CY3280-MBR Kit
CY8CMBR2044
CapSense Controller
(Demonstration)
On board
Battery Power
Supply
External
Power Supply
Through
Connector J2)
Short Circuit
Protection
Series pass
Controlled Switch
CapSense power
button
(CY8CMBR2044)
Four CapSense
buttons
Power
LED
Four Output LED
Power Through
Connector J5
without protection
Outputs and Hardware
Strapping input
connected to J1 and J2
