3.13 Limitations of Using Battery and External Power Supply

Battery Power:

The battery management circuit is designed for a 4.2V battery going to a downstream 3.3V regulator. When the battery voltage is near to the required minimum input voltage of the regulator, it can affect the regulated output. It is advised to use a fully charged battery for evaluation and to recharge the battery as soon as the low battery output indicator is turned ON.

External Power Supply Header:

The WBZ450 Curiosity Board is designed by default for evaluating the WBZ450PE Module and associated peripherals with an on-board 3.3V regulator. The following limitations apply for the circuitry if the WBZ450PE Module and associated circuitry is powered from external power supply header at other voltages:
  • Temperature Sensor MPC9700A (U16) – Standard operating voltage for the temperature sensor is 2.3-3.6V operation
  • User LED (D4) – Designed for 3.3V operation; LED brightness at lower voltages will be dull or no glow. To increase the emitted light level, the value of the series resistor (R42) can be lowered.
  • RGB Lighting LED (D3) – RGB lightning LED is powered from VBAT net. It requires either USB or battery power supply to be plugged in to be functional.