资料介绍
Photo sensors bridge the gap between light and elec-
tronics. Microchip’s Programmable Gain Amplifiers
(PGAs) are not well suited for precision applications
(such as CT scanners), but they can be effectively used
in position photo sensing applications minus the head-
aches of amplifier stability. When the two, six or eight-
channel PGA is used in this system, the other channels
can be used for other sensors or an array of photo sen-
sors without an increase in signal conditioning hardware
or PICmicro
®
microcontroller I/O pin consumption. The
multiplexer and high-speed conversion response of the
PGA / Analog-to-Digital (A/D) conversion allows the
photo sensor input signal to be sampled and quicklyM AN865
Sensing Light with a Programmable Gain Amplifier
converted to the digital domain. Switching from chan-
Author: Bonnie C. Baker
nel-to-channel is then easier with the Serial Peripheral
Microchip Technology Inc.
Interface (SPI) from the PICmicro microcontroller to
the PGA.
INTRODUCTION