Microchip Technology ADM00344 Data Sheet
RE46C190 Demo Board User’s Guide
DS51970A-page 14
© 2011 Microchip Technology Inc.
2.4
MODIFYING THE DEMO BOARD
The RE46C190 Demo Board can be modified to include a smoke chamber, or smoke
chamber components. Jumpers R19 and R20 can be removed to allow a photodiode
to be connected to the IRP and IRN pins of the IC, respectively. R17 and R18 can be
removed to allow an infrared LED to be connected to the IRCAP and IRED pins,
respectively.
chamber components. Jumpers R19 and R20 can be removed to allow a photodiode
to be connected to the IRP and IRN pins of the IC, respectively. R17 and R18 can be
removed to allow an infrared LED to be connected to the IRCAP and IRED pins,
respectively.
The removal of jumper R15 will disconnect the smoke chamber emulator from the
VBAT line. This allows the measurement of the smoke detector application average
input current. It is important that the toggle switch SW2 be placed in the OFF position
for this measurement.
VBAT line. This allows the measurement of the smoke detector application average
input current. It is important that the toggle switch SW2 be placed in the OFF position
for this measurement.
TABLE 2-2:
RE46C190 DEMO BOARD TEST POINTS
Test Point
Description
V
BAT
The battery voltage or power supply voltage
GND2
Second connection to V
SS
TEST
Connection to Pin 4 of the RE46C190 device and the push-to-test button
IRED
Connection to the smoke chamber emulator and to Pin 2 of the RE46C190
device
device
TEST2
Connection to Pin 5 of the RE46C190 device
GND
Connection to V
SS
V
DD
Connection to Pin 3 of the RE46C190 device
GLEDR
Connection to the green LED resistor and the green LED anode
IRCAP
Connection to the smoke chamber emulator and to Pin 11 of the RE46C190
device
device
GLED
Connection to the cathode of the green LED and to Pin 9 of the RE46C190
device
device
V
BST
Connection to Pin 15 of the RE46C190 device
RLEDR
Connection to the red LED resistor and the red LED anode
RLED
Connection to the red LED cathode and to Pin 8 of the RE46C190 device
IO
Connection to Pin 12 of the RE46C190 device
FEED
Connection to Pin 10 of the RE46C190 device
LX
Connection to Pin 16 of the RE46C190 device
HB
Connection to Pin 13 of the RE46C190 device
HS
Connection to Pin 14 of the RE46C190 device
WARNING
The input current measurement requires an ammeter setting that can handle the large
current draw of the boost regulator, while resolving microamperes of current. The
effective series resistance of the ammeter can affect the operation of the boost
regulator.
An alternative method for this measurement is to place a 100 µF capacitor between the
terminal VBAT and GND2, and connect one end of a 100
current draw of the boost regulator, while resolving microamperes of current. The
effective series resistance of the ammeter can affect the operation of the boost
regulator.
An alternative method for this measurement is to place a 100 µF capacitor between the
terminal VBAT and GND2, and connect one end of a 100
Ω resistor to VBAT. Connect the
ammeter to the other end of the resistor and then to the positive terminal of the power
supply, or battery. Connect the negative terminal of the battery or power supply to the
terminal GND2. This simple RC filter will smooth out the current peaks. The capacitor
should have a low ESR to minimize the voltage ripple at the VBAT terminal.
supply, or battery. Connect the negative terminal of the battery or power supply to the
terminal GND2. This simple RC filter will smooth out the current peaks. The capacitor
should have a low ESR to minimize the voltage ripple at the VBAT terminal.