User manual

Board Technical Information
 2010 Microchip Technology Inc. DS51662C-page 49
A.14 POWER SUPPLY
There are four ways to supply power to the PICDEM LCD 2:
• A 3V button cell (CR2032) can be plugged into BT1.
• A 9V, 100 mA unregulated AC to DC supply can be plugged into J5. A
power supply can be purchased through Microchip Technology
(Part Number AC162039).
• A 100 mA regulated DC supply of maximum +5V can be connected to the hooks
provided.
MPLAB ICD 2 users may use the ICD to power the target board to 5V, up to 200 mA,
for the following devices only: PIC18F8490, PIC16F/LF/1946/7, PIC16F946 and
PIC16F916. The PIC18F85J90 and PIC18F87J90 families of devices do not support
this capability.
The default power on the board is 5V. The board voltage can be varied based on
resistors populated on the PIM in conjunction with the processor being used.
FIGURE A-11: J15 POWER SUPPLY CIRCUIT SETTING EXAMPLES
Note: There is one J15 jumper associated with the power supply circuit. This
jumper must be correctly connected to select the required power supply.
Refer to Figure A-11 for jumper setting examples.
1
3
5
2
4
6
J15
VLCDBIAS = Battery
1
3
5
2
4
6
J15
1
3
5
2
4
6
J15
VLCDBIAS = VCC
a) External Supply with
VLCDBIAS Regulated
(Default): This is the recom-
mended jumper setting to
operate when using external
supply. This configuration
allows the VLCDBIAS to be
regulated to 3V even if the V
DD
of the board is higher than 3V.
VLCDBIAS = 3V, External Power
b) Battery Operation: This is the
recommend jumper setting
when operating on a battery. In
this configuration, VLCDBIAS is
directly connected to the battery
voltage.
c) External Supply with VLCDBIAS
Unregulated: This is not recom-
mended to use with on-board glass
as voltage higher than 3V may
damage the glass.
If an external glass is connected to
J2 and is capable of handling
higher voltages, then this jumper
setting allows V
CC to connect
directly to the VLCDBIAS when an
external power supply is used.
EXAMPLE A EXAMPLE B EXAMPLE C
Note: For all examples shown above, the voltage regulation on the VLCDBIAS for 3V is not required for the
regular operation of the module or device. It is added here for additional protection for the glass since
the board is capable of generating 3.3V or 5V depending on the PIM being used.